As I get closer to finalizing the plumbing for my 8v-71T install in my MC-5C, I realize that I could very easily add a charge-air cooler to the turbo. It would involve adding the intercooler, and the tubing from the turbo and back to the intake on top of the engine. I would use 3.5" diameter tubing, since that is the size of the turbo outlet and the manifold inlet. What else is involved? Is it as simple as just adding the cooler? is there a better way to pick a unit than just finding one that fits the space and has the in/out in the right locations? It adds horsepower, from what I understand, but is there a way to estimate the effect? does it make the engine run noticeably hotter or cooler?
Rule #1...If you cool the air going into the engine that alone will have the effect of cooling the engine so, to some small degree, you reduce the load on the rad. That is a MUST HAVE, way way good idea and worth ??????? But only if you are cooling the air because of some other reason. Water injection only serves to "cool" the combustion temp to allow running a more advanced timing without "ping" and that system works well. I have used it on two engines and I am a strong proponent for power and $ reasons.
Rule #2... Intercoolers don't increase the potential engine horsepower a single one or even a fraction. If you make 300HP with a Intercooler you will only make 300 with one. NO GAIN. Not one. Nada. Zip. The intercooler will only prevent you from loosing HP due to induction air temp. That adds up to 300 HP at the bottom of the hill and 300HP at the top of the hill. Without the IC you will start off with 300 at the bottom but as you pull harder your turbo will work harder and get hotter, as it should, and your intake air temp will start to climb. By the time you reach the top of the hill you may find that your "adjusted" HP has fallen to 200. Just a swag but you get the point.
Rule#3...By adding "volume"the intake air passage you will delay the intake air coming up to the air pressure that you should have with the turbo spooling at a given speed. Call this "turbo lag". Very annoying in a car but in keeping with the neck snapping throttle response you have come to know and love in a D pushing a bus. In short, things haven't changed much, but you can certainly tell the difference at the top of the hill. All those added pipes and the volume of the IC will combine to delay throttle response. The lower the temp of the charge air the better so a bigger IC is better in every regard but in a car it becomes maddening waiting for the power to "happen". Bigger is better. It's like .....well it's like lots a stuff. So fit in the biggest unit you can in that space and that you can afford. Call a IC manufacturer and learn the "ideal" size from a cost trade-off point. Then start looking hard for a used item that will give you some return on your labor investment. Maybe Clifford has the exact item you need in his back yard.......he has most everything else.
The benifit of an IC is huge and I think, personally, that you should make a serious effort, time and money, to include it in your design.
Brian, they really need a deflector under the blower for a air to air tough to find but you can build one with you skills and it will run cooler with more power and better fuel economy,not disputing John Ed but on a 8v92 air to air increases the hp around 8 % so says the DD bible cool air makes hp
good luck
Brian
An intercooler will decrease air charge temp. In a gas engine that means denser air and more oxygen to burn so you can add more fuel and get more output. With an old diesel (non DDEC) it will as JohnEd stated help it keep cooler and improve combustion due to more O2 but do not see much of an HP gain. Either reason in its own is a good reason to go with the air charge cooler both for your engine and the environment.
Brice
What is the deflector under the blower, and what does it do?
Brian
Brian, keep in mind the air to air on a 2 stroke requires a 2.59 or better A/R on the turbo for full benefit check section 14 of the DD bible it will show the changes in hp and torque with air to air with lower rpms and different injectors.
On TA engines the cooler is the deflector they distribute the air more even almost a must for bypass blowers with a turbo.
I always use one when I remove the after coolers some don't your call
good luck
Quote from: JohnEd on July 22, 2011, 09:18:25 AM
Rule#3...By adding "volume"the intake air passage you will delay the intake air coming up to the air pressure that you should have with the turbo spooling at a given speed. Call this "turbo lag". Very annoying in a car but in keeping with the neck snapping throttle response you have come to know and love in a D pushing a bus. In short, things haven't changed much, but you can certainly tell the difference at the top of the hill. All those added pipes and the volume of the IC will combine to delay throttle response.
Maybe I'm not reading this right, but how can a diesel's turbo lag be blamed on the length of its intake manifold and pipework? Diesels don't have throttles, so they are essentially working at WOT all the time - it's the quantity of fuel injected that determines their power output. In this sense, I suppose a diesel is rarely ever stoichiometric (sp?), unlike a gasoline engine. Is there any appreciable intake manifold vacuum with a diesel, and if so is there any difference between a non-turbo and a turbo diesel? Also, just to complicate matters, when we have a scavenge blower after the turbo in our 2-strokes, wouldn't that influence any turbo lag issues caused by intercoolers or aftercoolers?
Ow, my brain hurts.
Thanks, John
I think what happens is we ask for more fuel, more fuel is injected at that time, there isn't enough air to combust all the fuel, we get a little smoke, the added fuel that is burnt spools up the turbo, air catches up with fuel, no more smoke, lots of power. The lag is more in getting the turbo spooled up than the length of the intake. How important is instant throttle response anyway? My engine has one of the rack delay dohickeys on it to reduce smoke. But what do I know (not much!)
Brian
Quote from: Iceni John on July 22, 2011, 12:18:53 PM
Quote from: JohnEd on July 22, 2011, 09:18:25 AM
Rule#3...By adding "volume"the intake air passage you will delay the intake air coming up to the air pressure that you should have with the turbo spooling at a given speed. Call this "turbo lag". Very annoying in a car but in keeping with the neck snapping throttle response you have come to know and love in a D pushing a bus. In short, things haven't changed much, but you can certainly tell the difference at the top of the hill. All those added pipes and the volume of the IC will combine to delay throttle response.
Maybe I'm not reading this right, but how can a diesel's turbo lag be blamed on the length of its intake manifold and pipework? Diesels don't have throttles, so they are essentially working at WOT all the time - it's the quantity of fuel injected that determines their power output. In this sense, I suppose a diesel is rarely ever stoichiometric (sp?), unlike a gasoline engine. Is there any appreciable intake manifold vacuum with a diesel, and if so is there any difference between a non-turbo and a turbo diesel? Also, just to complicate matters, when we have a scavenge blower after the turbo in our 2-strokes, wouldn't that influence any turbo lag issues caused by intercoolers or aftercoolers?
Ow, my brain hurts.
Thanks, John
John,
You have it all pretty much correct as Brian pointed out. Regardless of whether you have the air being metered, the manifold pressure DOES fluctuate and there is a lag between the fuel delivery and the fuel/air delivery. The turbo "spools" up with the throttle demand. That spooling is one source of "lag". The other is that as the spooling takes place there is a lag in manifold pressure associated with the volume of the "tank" that is being brought to pressure. The "tank" in this example is the total volume of all the plumbing and the intercooler itself. My point here is that if you use a HUGE intercooler you will certainly get better cooling of the charge air but you will also be adding to the "lag" but in a D that isn't any concern. The cost goes up breathtakingly as you reach for those big intercoolers. No matter, you will get more performance regardless of the size so my rule is to go as large as you can fit/afford.
According to the DD rep I spoke with years ago..."the cooler the better. 400 degrees is the max charge air temp that a D will ruin on. Power drops quickly with any increase in charge air temp". Soooo get all the "chill" you can afford and lag be darned.
I have heard it said before that the "aftercooler", the water to air heat-exchanger that sits under the blower, can be eliminated without consequence. That isn't true. No more so than an intercooler contributes nothing. If you have one then keep it. If you have a "A" (for aftercooler) block then install one if you can find one and it is affordable. Here's the logic: The intercooler dumps the heat caused by the turbocharger compressing the charge air. That "cooled" air then feeds the blower/compressor that sits on top of the engine (V). That blower then further compresses the charge air and in so doing the compressor adds heat to the charge air. The "AFTER-COOLER" is intended to dump that heat into the coolant with the result being that the charge air temp increase attributable to the blower is reduced. Result is greater HP and efficiency.
As to the 8%.....that was negligible in that that power wasn't the justification for installing the IC. Rather, the IC prevents a much larger % of loss in HP due to charge air heat build-up and HP loss due to altitude. That figure does serve to prove the value of the IC if it also adds a smidge ta boot...LOL
I am pretty sure that the A functions as the Deflector also. It seems to me logical that in that small space above the intake manifold there would be a lot of turbulence at the outlet from the compressor. I don't know if you need to install a deflector if you remove the A or if you no longer need the deflector if you up-grade to a A. Either way.
I understand that "Don The Fairchild" has a 8V92 TA with IC that gets 9 mpg at 70 MPH in an aerodynamic( humor)Eagle or Prevost. I never heard Don say any such a thing and I have wondered how he did that....if the report was true. Eliminated the A? Big IC? Port and relieve? Headers? Injectors made from unobtainium? No muffler? Water injection? WHAT? There has to be an explanation. Wish I knew....folks....wish I knew.
John
Ok, is your 8V-71 T or TA?? Mine is a TA, another person that did an upgrade to a turboed engine, he started with a 8-71T and made it a 8-71TA. When I started looking I wanted a TA..
How much does the cooler under the blower do compared non cooler there?
Ralph, air from the turbo through the blower is over 300 degrees after the cooler in the block drops to 200 degrees to the air box lot of difference in the after cooler temps and the air to air charger temps about 1/2 for the air to air,the latter brings a 2 stroke to life just like it does on a Cat or Cummins that was equipped with a after cooler
good luck
JohnEd,
Thanks for that explanation. Now I know! This forum is amazing - there's not much that someone here doesn't know about.
John
Brian, as I recall, you are not going for big manifold pressure, but never-the-less, I would roll beads on all the tubing. The hoses are silicone and do not hold well. I used exhaust tubing and formed bends on mine (4 inch) and it went well.
The big item you will have to deal with is moving air across the cooler. That turbo puts a lot of heat into the air and you need to move a lot of air across the exchanger. If you put it in front of the radiator and use the bus fan, you will move air, but you will also add heat to the cooling system (less delta T).
I mounted mine on the opposite side of the radiator and tried electric fans. Never did work well. Finally made a deflector box so that I was not fighting the radiator fan and now have a hydraulic fan. That works OK, but I have to use misters to keep the intake temperature below 160* on the big hills.
Most "experts" say that the air temperature entering the engine should not be more than 50* above ambient in a system with a charge air cooler. I take a bit of liberty with that and say that I could hit 110* ambient, so I keep my max air temp at 160*
Jim
I think my project will be an iterative process, gradual upgrades. I'm sure that my first install will be simple - the turbo I have, which isn't the ideal one, and a straight shot into the manifold on top of the blower. Steps in future would be the right turbo and the intercooler, since I do believe that the gains are there to be had. My engine does not have an aftercooler or a bypass blower, so there is only so much I can get to.
But I have to say thanks for the support from the forum and the members on this. Clifford's sometimes cryptic comments take a little thinking about, but what help! Don Fairchild in particular has helped me understand the point of what I am trying to do.
Last weekend I finished fabricating the manifold for the top of the blower - I modified a cast DD manifold so that it suited the turbo being hung just off and below the drivers side valve cover instead of directly behind the engine where my air compressor lives. Welding that dirty cast aluminium was not my finest hour, but it's done. I have the exhaust manifold about half done, tomorrow's job is mitering in the cross pipe from the passenger side into the pipe on the drivers side towards the turbo flange. I am adding in several vee band clamps so that the whole thing can actually come off the engine once it's all done and finish-welded... My pressure side is going to be all beaded tubing, you bet! I'll post pictures in a week or so, my camera got left in Nova Scotia last time I visited down there.
Hot here, around 115 today heat index... I last about 6 minutes in the shop before my eyes are filled and stinging!
Brian
When you install that air to air cooler like stated roll those connectors for those silacone tube connectors and get the spring loaded screw hose clamps and wire that goes around the tubes. If you get a hole 1/4in in the system air loss you loose hugh HP.
Thanks Luvrbus, I did not the actual ##'s.
If you added a water to air Intercooler as shown in the detroit picture, would it work as well as a air to air?
Wouldn't have to add a lot of piping or extra fan as long as your existing radiator could handle it.
Anyone have or seen this application? Good topic as I am in the planning stages of a 6v92Ta for the old Eagle.
Build it big as long as I can get 100k out of it!!!
Thanks ED
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fi733.photobucket.com%2Falbums%2Fww340%2Fepbrenner%2F020.jpg&hash=ea5234520e5f5314f7b9b79ca1080bdb8f5bb32a)
Quote from: Ed Brenner on July 22, 2011, 07:06:31 PM
If you added a water to air Intercooler as shown in the detroit picture, would it work as well as a air to air?
Wouldn't have to add a lot of piping or extra fan as long as your existing radiator could handle it.
Anyone have or seen this application? Good topic as I am in the planning stages of a 6v92Ta for the old Eagle.
Build it big as long as I can get 100k out of it!!!
Thanks ED
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fi733.photobucket.com%2Falbums%2Fww340%2Fepbrenner%2F020.jpg&hash=ea5234520e5f5314f7b9b79ca1080bdb8f5bb32a)
Ed,
My man. Yes....many times over. The air to water exchanger can be made much smaller and it will drop the temp as much as you want to design. This is why a 8V71 can put out 700HP in a boat. They use the ocean as a heat sync. No HP used for a monster fan.....just pump water thru the IC for the chill. Now in tanks, I am told by Don. the radiator is 4 feet tall and stretches across the entire rear of the tank and has blowers that will blow your mind. BUT, they can get and maintain 700HP and Don told me long ago that 1,000 was doable from a 8V71 if I could dump the intake air temp and get rid of the engine heat. Simple, huh? Just a 3 inch water line and a water pump instead of all that pesky radiator and fan and shroud and...... The 1000 item would reliably run for a shorter period than a 250 HP tuned engine. Much shorter.
Most of what i am sharing is what have picked up listening to professionals and reading and cross pollinating from automotive topics I have worked with for many years. Be it me or anybody here I think it is incumbent on you to verify with professional sources for your sake and share your finding with us for ours.
John
Quote from: bevans6 on July 22, 2011, 03:34:43 PM
I think my project will be an iterative process, gradual upgrades. I'm sure that my first install will be simple - the turbo I have, which isn't the ideal one, and a straight shot into the manifold on top of the blower. Steps in future would be the right turbo and the intercooler, since I do believe that the gains are there to be had. My engine does not have an aftercooler or a bypass blower, so there is only so much I can get to.
But I have to say thanks for the support from the forum and the members on this. Clifford's sometimes cryptic comments take a little thinking about, but what help! Don Fairchild in particular has helped me understand the point of what I am trying to do.
Last weekend I finished fabricating the manifold for the top of the blower - I modified a cast DD manifold so that it suited the turbo being hung just off and below the drivers side valve cover instead of directly behind the engine where my air compressor lives. Welding that dirty cast aluminium was not my finest hour, but it's done. I have the exhaust manifold about half done, tomorrow's job is mitering in the cross pipe from the passenger side into the pipe on the drivers side towards the turbo flange. I am adding in several vee band clamps so that the whole thing can actually come off the engine once it's all done and finish-welded... My pressure side is going to be all beaded tubing, you bet! I'll post pictures in a week or so, my camera got left in Nova Scotia last time I visited down there.
Hot here, around 115 today heat index... I last about 6 minutes in the shop before my eyes are filled and stinging!
Brian
Brian,
My first upgrade would be the "Aftercooler" that sits under the blower/compressor. That is the item that Clifford says dumps 100 degrees form the intake charge air. DD gets by without a IC and dumps the superheated turbo compressed air into the blower. Even with this power robbing heat load the A seems to get everything to a safe temp. If you add a turbo to a block that isn't equipped with "anything" to lower charge air temp, I think you might be tempting fate and probably missing HP at the least. Just food for thought my friend.
My very best wish for your success and amusement throughout this adventure,
John
Question for Jim and Brian why the beaded pipe with silicone turbo hoses ? never saw that before on factory installs
good luck
Quote from: luvrbus on July 23, 2011, 05:45:33 AM
Question for Jim and Brian why the beaded pipe with silicone turbo hoses ? never saw that before on factory installs
good luck
Lvrbus
I haven't had any experience with DD turbo setups but in other turbos that run higher manifold pressures the Beaded pipe helps keep the hose from blowing off the pipe. Put your foot down hard feel the boost then everything goes away. You have blown a hose off.
Brice
Brice,thanks I was asking because the source (turbo) doesn't have a bead and reading the paper work on the silicone turbo hoses I have here it states not for use on beaded pipe I can see where rubber would be a problem but I never had a hose or pipe blow off with silicone hoses
good luck
John, adding an aftercooler isn't a bolt on accessory, it's a fundamental redesign of the engine intake system down to the block. Ain't going to happen after this engine is in the bus. If I was doing a high-bucks build of an ultimate engine instead of just trying to get some reliable rolling stock under me, then sure...
Clifford, the stock pressure side turbo tubing and hoses on my engine are all beaded including the turbo, it's not silicone hose though. I have a love/hate for silicone hose, I find it cold leaks with coolant. About the only good thing about it (aside from temperature resistance, longevity and all that technical stuff) is that it's a pretty blue colour. If I can buy high quality rubber hose in the appropriate size I use that every time.
Brian
Can you post a photo of the bead on the turbo I have never saw one and would like to see how they do that
After the 1st of the year we are going to build Van a 400-425 hp 8v92 high torque engine (8-9mpg) for his Eagle he is pretty good with a camera sure there will be lots of photo then some of the guys here can understand it not all that easy to just add things to a 2 stroke like a after cooler,already told him the gear driven 50D is history lol with me involved
good luck
Clifford, I can only speak to the turbos on Series 60 (I did not document, nor do I remember much about the 6V92 turbo). Those turbos have what I call a saddle clamp that clamps around a flange on the turbo and the flange on the adapter. That adapter has a bead on every one that I have seen. In addition, all of the stock Series 60 tubing has a bead on it as well. I have attached a photo of the tubing I made for my conversion.
I used a standard bead roller that is used in automotive fabrication (rolling beads in flat panels). It absolutely worked great. I did have to make a simple flange to seat the tubing against to get the bead started.
Even with the beads, I blew the hose off at least twice. You really have to stay on top of even the spring clamps until the silicon material stops "flowing". Those blow offs occurred during the period when I was not monitoring the air temperature and I suspect that one blew off when the air temperature was over 200*. The other one occurred on a flat road and should not have been caused by high air temperature.
I have never seen a rubber air to air hose. Everyone I have seen is silicone. And for good reason. There is no kind of rubber compound that would withstand the high temperatures in the system.
On water to air coolers, the one shown in the picture is most likely for a boat application where the cool water would take the air down to a reasonable level (probably less than 120*.
On the DD 2-stroke water inner-cooler, I always scratch my head. When you need the cooling the most - lots of turbo boost, the water will be at it's highest. Even if you use water right out of the radiator (cooler), it is probably at least 160* and the cooler is pretty small for the air flow. I can't imagine that the air entering the engine is less than 180 degrees. That is much higher than is considered acceptable - at least for 4-strokes.
Brian, I would be extremely concerned if you add a turbo and do not use either an air to air, or the DD water heat exchange. You need one or the other, or you will be introducing very high air temperatures to the engine.
Jim
Jim, I hear you on the intercooler, hence this thread, but remember I'm not "adding" a turbo, I'm simply changing the location of the stock turbo. The result is going to be pretty exactly the same as Detroit built it in the first place, it's a legit 8v-71T.
Clifford, the bead on the turbo outlet is simply a raised ring around the exit point of the pressure side, about 1/4" wide and 1/16" tall. The hose slips over it and the band clamp goes behind it, towards the turbo side. It isn't much.
Brian
The saddle clamps and flange I buy Jim I just have never saw a bead on a 2 stroke turbo or a saddle clamp always a spring loaded clamp and silicone hose on the cold side even when they change sizes as some do it is a molded silicone hose with 2 different sizes of ends not trying to start a argument here just want to make sure my eyes are not lying to me, cold side connection not the hot housing connection
good luck
Quote from: bevans6 on July 23, 2011, 08:57:16 AM
Jim, I hear you on the intercooler, hence this thread, but remember I'm not "adding" a turbo, I'm simply changing the location of the stock turbo. The result is going to be pretty exactly the same as Detroit built it in the first place, it's a legit 8v-71T.
Clifford, the bead on the turbo outlet is simply a raised ring around the exit point of the pressure side, about 1/4" wide and 1/16" tall. The hose slips over it and the band clamp goes behind it, towards the turbo side. It isn't much.
Brian
We have a disconnect.....on my end...at least. Someone with a "book" should be able to answer this: I thought that the A(aftercooler) was an option on the "N" engine. I read once that the N without a A option didn't have the machine work done to allow it to accept a After-cooler....missing casting components or perches or something. Tearing down your 8V71N to install the spendy aftercooler you bought and finding out that you can't install one in your block would meet my definition of a bad day. Concerns such as these drive some of my questions and pedestrian comments.
Secondly; I thought that ALL "T" designated engines came with a After-cooler featured block. Obviously I don't have the books to research the authoritative answers.
Third: You are right about my missing some of your points. That comment about not having the correct turbo led me to believe that the engine was not originally turbo equipped. If it is a fully equipped turbo engine then I can't see for a minute why you couldn't install a turbo with somewhat less capacity. Getting the temp of the charge air lower than the original spec without a IC wouldn't require any mod to the engine in the least in regards to "accommodating" that lower temp. Lower is better...withing reason.
Anybody have a set of DD manuals that I could have or buy cheap? Even armed, as it were, with a complete DD library, Clifford has been corrected for missing a table or dropping a stitch or getting crossed up with the line. Hey, if it can happen to "The Clifford"...well? Just not saying that having a manual would make me bulletproof and a source that could not be challenged cause that would run right into my humility "fire wall".
John
I thought you guys may get a laugh from this but I am into a 8v71T in 4905A this bus has flexible aluminum dryer duct from the turbo to the intake about 3 ft no after cooler or inter cooler and this bus has ran for 20 years without a hiccup lol just now separated a liner that I told him would happen 20 years ago so here I am with egg on my face repairing a engine that I thought would last maybe 6 months.Jim old Don Gourley has a 71 turbo in his Eagle without a aftercooler or inter cooler
good luck
Clifford, yes they had that type turbo aftercooler,forgot about it.
The engine must have the correct water ports, N and T engines do not normally have them.
8-71T engines highest safest, HP 350.-- 8-71TA --- 400 HP ------- Mine about 375 HP and with good radiators gets HOT on I-81 hills,,,, and I have not learned to slow down and down shift soon enough, it is a 740 auto with air only oil cooler.
Clifford, the person here has an Eagle that they took a 8-71T military, had water ports so they added the aftercooler, moved the side turbo. He had a bad radiator so replaced it at the same time with a new radiator. The Eagle has a standard trans. On the first tirp
Don't know ??? but will try to finish....
On his first trip after install , some distance tween Pa. an Los Vages it ran warm, maybe he ran slower after that. It was the fall of 2009 cause I ran to N.M.- Az. also.
So my ???? on 8-92 cooling, is/will the temp. guage be telling the right foot to lighten???
Yep Ralph you can dress these old girls or guys about anyway you choose too they are not the best looking at the party but will stay till the party is over with a little TLC
good luck
Quote from: Ralph7 on July 23, 2011, 11:44:52 AM
Clifford, yes they had that type turbo aftercooler,forgot about it.
The engine must have the correct water ports, N and T engines do not normally have them.
8-71T engines highest safest, HP 350.-- 8-71TA --- 400 HP ------- Mine about 375 HP and with good radiators gets HOT on I-81 hills,,,, and I have not learned to slow down and down shift soon enough, it is a 740 auto with air only oil cooler.
Clifford, the person here has an Eagle that they took a 8-71T military, had water ports so they added the aftercooler, moved the side turbo. He had a bad radiator so replaced it at the same time with a new radiator. The Eagle has a standard trans. On the first tirp
Ralph,
Thanks for that info. Three versioins of the 8V71 block...as I understand you.
Set at 375 HP what are you getting for MPG?
Thanks,
John
What a good thread, I am glad I asked the original question, whatever that was.
My new engine has the aftercooler port hole in the block but it has a pre-heater in it, kind of a diesel blow torch to warm up the air inside the engine so it will start in those cold cold winters... so I could add an aftercooler, but I won't. I have no intention of taking off that blower until needs force me to...
So I looked in my book. In the 1980 V71 manual there were 8V71N's, 8V71E's, 8V71T's 8V71TA's. 8V71TTA's, 8V71TTE's, and a sub-class with a C suffix for California... There were 8V71N blocks with no after cooler port, and blocks with that port machined in (it's on the flat block surface kind of between the fuel pump and the governor, space for a hose fitting to the cooling system). There are at least 5 different turbo's. This leads to many many different combinations.
Brian
I get 5.5--7.2mpg.,the old engine had 70 injectors and was tired, it is a 8-71N and sits in my shed. My driving is 55-60, but drifts to 65. Full speed on level 71, all according to GPS, speedo not good.
I replaced the 4 worn throtle ball joints and now have about 1 1/4 in. peddle to full throttle.
Also I have 1 ea 12V. 50A alt., and 1ea 24V. 50A alt. .... My soon replace the 12V-50A with a 12V 160A alt.
My latest addition 4 ea 210 watt solar panels, on roof, so how will this affect??
I am glad you did also ????E ----TT are 2 turbos.
I thought I would bring this to the top again, as my mind can't grasp not having some kind of air cooling system when a turbo is involved.
Clifford, I want to make sure that you are saying that both the GM you are working on and Don's engines do not have any mechanism/system to cool the incoming air.
If that is the case, then the air entering the engine is well above 250 degrees and probably often above 300 degrees. I arrive at those numbers through my experience. My intake manifold air temperature will easily get to 200 degrees - after my charge air cooler. Admittedly my charge air cooler is not as efficient as some, but I have seen 240 degrees on my first Series 60 engine.
If the air entering the blower is hot, then it will get a bit hotter going through the blower (even with the bypass).
If the air temperature is over 300 degrees on a long hill (I think that might be low with no means of cooling the air), that is huge when you consider that temperature occurs before the combustion process.
As I say, my mind can't grasp that those temperatures will not do some long term damage to an engine. On the other hand, there appears to be evidence that the engine can and does do OK
So, is the ability to deal with the high intake temperatures unique to the two stroke?
Anyone got a technical explanation why the engines live under these conditions.
Obviously I am asking because I have become anal about keeping my intake air temperature below 160 degrees in my Series 60.
Jim
Jim, DD had the 8v71T no type cooler what so ever DD could get outside the box with their coolers like ALCC shown in the photos,but all engine manufactures CAT,Cummins,DD whoever had engines with just turbos no air cooling that came later with the aftercooled and they all used that also.
Just to be clear I prefer a cooler of some type after or inter I think air to air is the best they need some type cooler JMO,the little aftercooler the DD uses does help with dropping the temps
good luck
Clifford, thanks. Now that you mention it, I have been to a couple of AHTS shows and see old engines with turbos and no air to air.
Now the question becomes, what is acceptable intake temperature for more modern 4-stroke engines (some of the older 4-stoke engines did not use air to air per the above). I did a ton of looking a couple of years ago and could not find much. I did find that the charge air coolers are designed for the 50* over ambient, but even the references I found were vague.
The SilverLeaf VMSpc air inlet temperature gauge has an optional bar graph that shows the red area at about 140-150 degrees as I recall. I asked Martin where he came up with that value and he said that he was guessing ::)
In lieu of better data, I guess I will stay with the 160* and hit the misters to keep it at that max value.
Jim
Jim, I just got off the phone with Cole he said 165 max for the non EGR series 60, 172 for the EGR 12.7 or 14 L he going to send me the chart on flows and temps then I'll forward it to you he told me your DD dealer should have the chart.
Fwiw he said the flow is the most important part of the system they spent tons of money for research on the flow and temp he got too technical for me on the rest lol your type guy
good luck
I have a feeling, unsubstantiated by anything in particular, that one reason 2 strokes might get away with a higher intake charge temperature is that the 2 stroke engine is so inefficient, relative to a 4 stroke. Given that we have twice as many combustion events per rotation compared to a 4 stroke, we don't get even half as much power per combustion event. That means that we don't generate as much heat and our exhaust gas temps are a lot lower. Maybe a little extra heat helps a bit, who knows? I have heard that the blower alone heats the intake air charge to over 200 degrees.
Brian
Brian a turbo charged 2-stroke engine is twice as efficient as a 4-stroke. You can get more power per cu in to weight ratio then with a 4-stroke. you have half the parasite loss of a 4-stroke.
Don
Have you considered going to a DEDICATED SEPARATE RADIATOR just for the intercooler WATER going thru the air to water DD intercooler under the blower? Also a dedicated SEPARATE air to air intercooler radiator location that keeps the extra heat from the water engine radiator?
Also consider a much bigger, lower resistance intake air filture? Finally, have you considered going to 5" intake turbo plumbing with gentle SWEEPS instead of the abrupt tight bend 3" to 4" typical on most installations? Finally finally, a low resistance LOUD exhaust system that sounds bitchin'?
Like already said, the whole shebang must be designed to come apart into separate pieces soss it can be installed and removed while your mighty Detroit is installed in your Bus Conversion. Sounds like a whole bunch of fun and games figuring out all of this. Lower temps, more boost, lesser increased fuel= high power, lower EGT, no smoke, long life. HB of CJ (old coot)
Don, I was thinking purely on a per combustion event basis, disregarding the other inefficiencies, in order to translate combustion efficiency into exhaust temperatures. I was thinking that the intake/exhaust events could be more optimized in a 4 stroke, hence more efficient. Also the intake porting could be better than dumping air into the air box then through the intake slots in the cylinder. On the other hand, getting twice as many events/rotation is a handy advantage. I recall the two stroke motorcycle engines of my youth, expansion chambers on a buddies RD350, and my own Kawasaki 500cc triple that would wheelie at 60 mph in third gear if you weren't careful... Mind you, it got 25 mpg, had a three gallon tank, and got around 500 miles per spark plug. It came stock with a set of three spare spark plugs...Ah youth - that seemed so logical at the time!
What is your thought on the charge air cooler debate? I would love to know what your research has shown!
Brian
Difference between an air to air intercooled 8V-71 turbo and just a straight 8V-71 turbo-with the same 75 injectors, the turbocharged 8V-71 will put out 350hp and 1,035lb/ft torque. With my setup of the 9G75's and a custom made air to air intercooler with 4" hoses to properly flow, my engine on the dyno put out 375hp and 1125lb/ft torque. This is why virtually all pickup and big rig trucks have air to air intercooling-makes for the densest air possible coming into the engine. And as you can see, there is a difference in power with the same injectors. Good Luck, TomC
I turboed the 4-71 in my Courier 96 a couple years ago. I built a air to air intercooler for it. I was only getting 8 to 10 lbs of boost with it. I quit fooling around with it and removed it after I noticed the pictures of the 4-71T engines in my DD manual without air coolers. The turbo is plumbed straight into the blower. So that is what I did. I now get 15 lbs of boost and it still works very well after 20 000 miles. I don't have overheating issues.
JC
JC,
That seems to make sense to me. You compressed the air and heated it up. Then when you cooled that air and it shrank and that registered as a drop in pressure. The air also became more dense and oxygen rich by weight/mass. By removing the intercooler you increased the pressure but you also increased the temp of the charge air. The temp bump cost you power and efficiency and the pressure you picked up is only "hot air"....no pun intended nor sarcasm. I think the solution you might have been looking for would have been a turbo that was sized for your system design considering that you would cool the air. The "stock" system assumes that you will be dumping that hot air into the blower. I think cool air at 15 psi would net you better all around performance than the hot air design you have arrived at.
Can't argue with success, however.....if you have the power you want then you have arrived. Did you keep your Inter-Cooler? That you have no heating problems follows as you now seem to have a "stock" DD designed system. If you cooled the charge air on you current system you would get a cooler exhaust and I guess cooler is better. (Fonze quote)
Thanks,
John
JC, you cannot take a standard turbo on a DD and make it work on a air to air changes need to be made like a different turbo with different A/R or you will have low boost
good luck
I remember getting the turbo that is specified for the stock 4-71T. (I don't remember the numbers for it). I just built a basic engine, and am happy with a great increase in power and it runs well.
The 6V92 in my 5C could use some tweeking as well, such as different injectors, different turbo, etc, but it runs well as is, so I will leave it alone for now, at least until I have a really slow winter, ;)
The moral of the story is that there are many factors involved in building an engine to achieve a desired result, such as port hole size, injector size, std versus advanced timing, size of turbo, etc, etc. As well as tuning like injector height, valve clearances, etc, etc.
The DIY care and maintenance of the bus is what makes this hobby so much fun for me.
JC
Yep and if you start with the wrong blower drive ratio and blower you are screwed to start with lol
good luck
On the subject of turbochargers, on my setup, Don Fairchild used a turbo from a 12.7 Series 60 that has a waste gate to keep the boost below 15psi since I still have the high compression pistons. It works well with virtually no smoke on a pull. The only draw back is the long exhaust run where Don had to mount the turbo (above the engine and behind the top valve cover on a V drive). It takes a couple of minutes to warm up with a bit of smoke-once warm-no smoke. If you open the engine compartment, you can really feel the difference between the hot side and cool side of the intercooler. Good Luck, TomC
Quote from: lostagain on July 26, 2011, 08:32:52 PM
I turboed the 4-71 in my Courier 96 a couple years ago. I built a air to air intercooler for it. I was only getting 8 to 10 lbs of boost with it. I quit fooling around with it and removed it after I noticed the pictures of the 4-71T engines in my DD manual without air coolers. The turbo is plumbed straight into the blower. So that is what I did. I now get 15 lbs of boost and it still works very well after 20 000 miles. I don't have overheating issues.
JC
JC, something is not right here. You should not have lost half of your boost through the air to air if everything was sealing properly and the air to air was properly sized. There will be flow loses, but that could not begin to account for your huge pressure loss. All modern trucks use air to air and the boost is not drastically reduced by the cooler circuit.
Quote from: JohnEd on July 26, 2011, 09:12:01 PM
That seems to make sense to me. You compressed the air and heated it up. Then when you cooled that air and it shrank and that registered as a drop in pressure. The air also became more dense and oxygen rich by weight/mass. By removing the intercooler you increased the pressure but you also increased the temp of the charge air. The temp bump cost you power and efficiency and the pressure you picked up is only "hot air"....no pun intended nor sarcasm. I think the solution you might have been looking for would have been a turbo that was sized for your system design considering that you would cool the air. The "stock" system assumes that you will be dumping that hot air into the blower. I think cool air at 15 psi would net you better all around performance than the hot air design you have arrived at.
Can't argue with success, however.....if you have the power you want then you have arrived. Did you keep your Inter-Cooler? That you have no heating problems follows as you now seem to have a "stock" DD designed system. If you cooled the charge air on you current system you would get a cooler exhaust and I guess cooler is better. (Fonze quote)
JohnEd, it sounds like you are citing Boyle's Law (http://en.wikipedia.org/wiki/Boyle%27s_law (http://en.wikipedia.org/wiki/Boyle%27s_law) ) but that is for a closed system. This system is definitely not a closed system. There is just no way that a properly designed and installed air to air cooler will drop the boost by half.
Jim
Jim is correct. Considering the new trucks have boost pressures up towards 50psi. And that's after the air to air. My guess is that the plumbing was either leaking or wasn't big enough to flow the air properly. I use 4" hoses for my air to air and 5" exhaust for the 8V-71. Good Luck, TomC
A older DD turbo will not supply enough volume with a air to air to make much boost DD is very specific on what turbo and blower to use for air to air on a 92 series don't think you will find any info for air to air on a 4-71 engine lol you guys are leaving the blower out of the loop for some reason that thing sucks a lot of air away from a turbo that is why DD mounted those on top of the blower or as close as they could get it for the after cooled engines
good luck
Quote from: rv_safetyman on July 27, 2011, 07:46:23 AM
Quote from: lostagain on July 26, 2011, 08:32:52 PM
I turboed the 4-71 in my Courier 96 a couple years ago. I built a air to air intercooler for it. I was only getting 8 to 10 lbs of boost with it. I quit fooling around with it and removed it after I noticed the pictures of the 4-71T engines in my DD manual without air coolers. The turbo is plumbed straight into the blower. So that is what I did. I now get 15 lbs of boost and it still works very well after 20 000 miles. I don't have overheating issues.
JC
JC, something is not right here. You should not have lost half of your boost through the air to air if everything was sealing properly and the air to air was properly sized. There will be flow loses, but that could not begin to account for your huge pressure loss. All modern trucks use air to air and the boost is not drastically reduced by the cooler circuit.
Quote from: JohnEd on July 26, 2011, 09:12:01 PM
That seems to make sense to me. You compressed the air and heated it up. Then when you cooled that air and it shrank and that registered as a drop in pressure. The air also became more dense and oxygen rich by weight/mass. By removing the intercooler you increased the pressure but you also increased the temp of the charge air. The temp bump cost you power and efficiency and the pressure you picked up is only "hot air"....no pun intended nor sarcasm. I think the solution you might have been looking for would have been a turbo that was sized for your system design considering that you would cool the air. The "stock" system assumes that you will be dumping that hot air into the blower. I think cool air at 15 psi would net you better all around performance than the hot air design you have arrived at.
Can't argue with success, however.....if you have the power you want then you have arrived. Did you keep your Inter-Cooler? That you have no heating problems follows as you now seem to have a "stock" DD designed system. If you cooled the charge air on you current system you would get a cooler exhaust and I guess cooler is better. (Fonze quote)
JohnEd, it sounds like you are citing Boyle's Law (http://en.wikipedia.org/wiki/Boyle%27s_law (http://en.wikipedia.org/wiki/Boyle%27s_law) ) but that is for a closed system. This system is definitely not a closed system. There is just no way that a properly designed and installed air to air cooler will drop the boost by half.
Jim
Jim,
That was my point. His system was NOT properly sized. He took a design that did not include a intercooler and added one. The pressure MUST go down if the turbo is NOT waste-gated due to his cooling the charge air.. Now "how much" it should have gone down is the sticky wicket. I sure dunno. But, at least part of what JC experienced should have been anticipated. Maybe not by him, and for sure not by me, but in retrospect and having the question it clears up. I asked if JC still had that IC for two reasons: One is that it is a valuable item and secondly he might pressure test it for additional info.
Jim,
Boyle's law? Naw, way to brainiac for this kid. I took High School Physics and have found it to be the most useful course of my entire life....bar none, and I have 4 degrees and a MBA. I am pretty sure the teacher mentioned "Boyle's Law", or should have, but you can't prove it by me. I just know that if you heat air it expands and if you chill it it contracts. Actually Boyle's Law does not apply because in that Law the temp is held
constant. That is exactly not what I was saying. It is Charle's Law (AKA Chuck) that draws the relationship of volume and pressure being affected by temperature and how. The "hole" thing gets tied together by the "Combined Law", appropriately monicker, that does what you might expect. Now don't get me wrong....I am not pulling rank on you, Jim. I never heard of those laws till I read your Wikipedia reference that you kindly included in your reply. Great info and thanks. ;D 8)
John the enlightened