As I seek the plumbing to put a turbocharged engine in an MC5c – with its low-clearance engine compartment – I'm trying to identify rigs that arrived from the factory with a low-profile turbocharger on a 6V71TA (maybe turbo-6V92 instead). A little research leaves me with the impression that these buses were available, at some point, powered by a 6V71TA:
• GMC RTS II (slope back)
• Blue Bird "City Bird" (1985 & 1986)
• Flxible Metro (model 40102-6TL ?)
• Gillig Phantom (1980 to 1994)
• Grumman 870 (model 40102-6-1 ?)
I am, however, unable to find where the turbo was located in any of these applications. Top? Side? Front? Back?
Somewhere I saw mention of V-6 DD engines in Eagle buses having a lower profile than those in MCI buses.
Perhaps somebody out there knows of a truck that carried a DD V-6 with a low-slung turbo -- and how to connect with a parts supplier or salvage yard that might have the turbo & plumbing in inventory.
Again, what I need is the plumbing to mount a turbocharger low on the engine. If it comes bundled with the turbo, that's okay. If one is available attached to the engine, I would consider it – if I can use that engine.
Whether their response is, "yeah, the engines in a [make, model] had a low-slung turbo" or "I know where you can get that hardware. Give these folks a call", any help folks could give me in this scavenger hunt would be appreciated.
They mount on the passenger side not a easy task but doable,there is no kit I know of I have the top air horn and y but no manifolds or piping.Eagle used a front mounted turbo but they didn't have a belt drive going from the crank to the blower fan like a MCI
Quote from: Craig R on September 29, 2015, 07:59:26 PM
As I seek the plumbing to put a turbocharged engine in an MC5c – with its low-clearance engine compartment
I'm looking for the same plumbing for the same project.
I have a 6V92TA available to me, just need the plumbing to hang the turbo off the side of the engine.
Shall keep an eye on this thread!
;)
I talked to a guy in NYC about 15 years ago with a 5C and a turboed 6/71. The engine was out and rebuilt. He wanted to sell, I bought another 5c. Then I saw he was giving the bus away or he was scrapping it. That engine may still be there, but where? He was north of the city, 30-40 minutes from ground zero. He was not junking it, but I have no contact info. Sorry
Why not just use your original manifold and weld up the mount you want out of stainless? Then it will go anywhere. rdw
Check Brian Evans posts he did all his own fab work on his system for a turbo 8v71 in a MCI 5.when I did my 6v92 in our 5 most of my parts came from Pedco in Ca,you need straight exit manifolds or the middle exit for easier installation
My 5C has a 6V92TA. The turbo is on the driver's side. I did not do the installation. A PO had it done. I don't know of any source for the plumbing and parts. You probably have to custom fabricate everything, which is what I did when I turboed the 4-71 in my Courier 96.
JC
Here, for the idea, is an off-the-shelf turbo install for an 8V-71. It is out of an M109 self propelled howitzer, and if it's still tuned stock has N80 injectors and 400 hp. It is a slightly different version of the one I installed in my MC-5C, but I really think this turbo mount would fit in a 5C. You'd still have to demilitarize it, but the exhaust manifold is perfect.
http://www.flanderstechsupply.com/gallery/engines/Motor%20M109%20detroit%20diesel%208V71T.cfm (http://www.flanderstechsupply.com/gallery/engines/Motor%20M109%20detroit%20diesel%208V71T.cfm)
Brian
I think Pedco did yours JC,I don't see wasting the money turboing a 6V71 but it is his dime
I can tell you from my experience that turboing the 8V-71 REALLY wakes it up. If you rebuild to turbo specs, you can get 400hp with 1200lb/ft torque with 80 injectors. MTU still makes the 8V-71 for military use (as also the 8V-92TA and 6V-53TI for the M113 [over 80,000 built!]). I use only 7G75 injectors since I still have high compression pistons with boost being at 15psi using a 12.7 liter Series 60 turbo with waste gate. Have had no problems in the 20,000mi I've driven it. Good Luck, TomC
You really push a 6v71 over the edge trying to get 280 hp from one they don't last.
Quote from: luvrbus on September 30, 2015, 06:36:29 AM
I think Pedco did yours JC. . .
Clifford -
Is Pedco still doing two-strokes? Or, for that matter, are they still around?
RJ
They are still around just that Virgil sold out to the Ironman group the Santa Fe Springs shop is still there and Virgil hangs out there sometimes and they still sell new and used parts for the old engines
I always thought the 6v71's were just as tough as the 6v53's.. I compound turbocharged the one in my 72 f350..drove the wheel's off it ..Didn't know the 71's were weaker. rdw
hi
my 1978 5c has a 692 turbo. The pervious owner installed it. It appears the only thing he did was raise the blower deck about 4 inches. I can send pics if you'd like
Chris
Does anybody know how one set of the hardware for a 12V71TA -- one of the two manifolds connected to one of the two turbo's that is powered by one of the two cylinder banks :D :). I recall having heard that the 12V71 is two 6V71's put together. It seems like, if the intake manifold for the front OR rear 6 cylinders would fit on the Roots, the turbo would end up hanging off the near side and fabricating pipe from the far exhaust manifold would finish the job. :) :D
The 12v71 used a one piece block, unlike the 12v92.
RJ,
American Fleet Inc in Springfield Missouri has 2 cycles cores in stock. Place a order and the engine usually ships out 3-4 days later ready to just drop in and go. Give me a call and i can quote you whatever you need.
... with a low-slung turbo, Detroitenginespecialist ?
So, could one of the two manifolds from a turbocharged 12V92 be used on a 6V71, chessie4905? ... and the 12V71TA still looks like it has two manifolds.
The 12v71 does use 4 manifolds or 2 singles either one all turbo models including the 92 series use the same 2-1/2 in ID manifolds not the 3in ID from a N/A engine.
You can buy what ever you want from Diesel Pro new but at a cost.I don't quite figure this out surely you know one just doesn't slap a turbo on a 6v71 and call it good
:o :-[ Tell me more, Luvrbus ! I mean about "one just doesn't slap a turbo on a 6V71 & call it good". I was looking at an industrial 6V71TA for sale (with the turbo on the top, of course). The local mechanic I've been talking to leans toward converting my naturally aspirated engine. Either way, I need to push the turbo down over the side. Can one use a 12V* manifold and/or ducting to move the turbo from the top of a 6V71 to the side? If so, and if you start with a 6V71TA, do you need to replace the manifold ... or just the ducting? I'll be very grateful for any insight you can offer.
Top mounted turbos drain the oil back through the blower you will need a different air horn and plug the oil drain hole then you need the drain adapter for the turbo to drain into the engine , some how I missed the buying of a industrial 6v71T engine. Finding a 2 piece manifold off a 12v71 is going to be nearly impossible there was only a hand full of 4 turbos 12v71 ever made
Quote from: luvrbus on October 01, 2015, 07:34:38 PM
there was only a hand full of 4 turbos 12v71 ever made
We had a few of them on 48" hydro-static test back in 1974-75..iirc ???
Nope, luvrbus. You didn't miss it; I didn't mention it.
The local mechanic wants to start with the N/A that's in the bus now and I was focusing on the locating of the turbo on the side -- whether it was relocating one on a TA or hanging a new one on a former N/A.
I'm gathering from your reaction that trying to convert a naturally aspirated engine into a turbocharged one ain't the way to go.
Do you know how I can identify the stock parts and where I can get the specialized parts needed to relocate the turbo to where it hangs on the 12V71 or 92?
Being on the side, Do the 12V turbos have that drain adaptor you spoke of?
Thanks!
4-turbo 12V71's sounds like two turbos per bank or one turbo for each three cylinders. The one I saw being fired up on a U-Tube video had one turbo hanging off each side -- one appearing to pressurize the front six cylinders (front three of each bank) and the other appearing to pressurize the back six (back three of each bank). I wonder if a person could bolt one of the air horns from a two-turbo 12V71TA to the intake manifold of a 6V71TA to mount one turbo beside the V6 engine.
Here is a pic of how I did the manifolds on my 8V-71T to put it in my MC-5C. You could do the manifolds on your 6V-91 exactly the same if you wanted to. FWIW the blower intake cover I "cut-and-shut" from the stock one that came with the engine, and Tig welded it together. I got the height wrong by 1/4" which I discovered when I first tried to install the engine, I had to take it off and take a bit off the top... ;D
I bought tube bends from a specialty racing supply house that did the tight radius mandrel bent bends (constant diameter in the tube, no wrinkles), I used 16 gauge tube, and I bought the stainless steel vee band clamp fixtures to join the pieces together. Material cost was around $800 delivered to my shop in Hamilton Ontario at the time. I added a slip joint in the section that goes across the front of the engine, it wanted to move too much with heat cycles. I built it to fit together with perfected fit, the first time I took it off after running the engine it had moved a bit and wouldn't go back on!
Cheers, Brian
The military 8V71t I started with. Note turbo is hung off the back, where the accessories attach on an MCI engine. The military engine had no accessory drives at all, just covers over the holes.
Brian
So, these are before & after pictures, bevans6 ?
Thanks :D :)
Yes, the first set of pictures are during the conversion process, when I had just finished roughing in the intake and exhaust manifolds. The second two are when I was picking it up from a farmer's shed, where it had been stored for many years. It was a NOS rebuild, zero miles on it, originally a NATO engine for a M110 self propelled howitzer or a variant thereof. The story is here: http://www.busconversions.com/bbs/index.php?topic=21836.0 (http://www.busconversions.com/bbs/index.php?topic=21836.0)
Brian
Well, fellas, a funny thing happened on the way to enlightenment! I took my little flashlight and peered into the engine compartment of my MC5c at what i believed to be a stock naturally aspirated 6V71; staring back at me was an air shut-down housing with an inlet fitting pointing toward the side. A guy recently told me that the shut-down housing on every V71 has the same bolt pattern. Maybe I'm well on my way to hanging the turbo off the side of the 6V71TA I'm trying to replace the NA engine with ... what do you fellas think? What does any of you know about this?
I don't how well that will work out for you the air horn on 6v92TA is only 3 inches O.D with 2.5 turbo I.D it's only 3.5 inches for 500 hp 8v92 I seriously doubt you can get boost using that big of a inlet
I'm confused by your observation, luvrbus. what I'm looking at in my engine bay is a naturally aspirated 6V71 hooked to an air shut-down housing with an inlet fitting pointing toward the side. The fella I was talking to indicated that the air shut-down housing & blower on a V92 have a different bolt pattern that won't fit on a V71.
I don't where he is getting that from the blowers are tapped for different bolt patterns is yours 4 bolts? ,on the blower there are 2 rows of tapped holes the inside row is for a 71 series the out side row which has more tapped holes are for the 92 series
I use the high capacity blower with a bypass off the 92 series on a V71 all the time even being a 1/4 inch larger they work. I never remember seeing a bypass blower made for a 6V71 either we always used one from a 6v92 so I don't know really what he is saying
what's a bypass blower? ??? :-[
Quote from: Craig R on October 10, 2015, 01:42:44 PM
what's a bypass blower? ??? :-[
one with a hole in it ;D
(https://www.powerlinecomponents.com/catalog/img/PCI/pgid/305/V71_mini_bypass_pg110.jpg)
(https://busconversionmagazine.com/forum/proxy.php?request=http%3A%2F%2Fdieselpro.com%2Fmedia%2Fcatalog%2Fproduct%2Fcache%2F1%2Fimage%2F9df78eab33525d08d6e5fb8d27136e95%2Fd%2Fe%2Fdetroit_diesel_6v92_12v92_blower_by_pass_blow_6v92_bp_soplador.jpg&hash=992672485fad9ac36e2668e20cb835e8049a7d6e)
You might have two air intakes on that blower top, around 4" diameter, going over to the stock air cleaner array (plus the air compressor draws clean air from the air cleaner before the blower top). To be honest, the air intake is not a big problem, a fabricator can make you one in a day. The large size of the intake, or even the two intakes, is an issue in that the air from the turbo needs to keep all of it's velocity, and the larger than ideal size slows the air down and that kills boost. The turbo to intake tube on my 8v-71T is a single 3" tube. You can take that air intake, cut off the air intake tubes and weld on a 3" one where you want it. That is what I did on my engine.
The bypass blower thing is a different question. I personally do not have a bypass blower on my engine, and it did not come with one stock as a military turbo engine, so I am certain that it is not actually needed. What the bypass does is pass air from the intake side to the air box side of the blower to equalize the pressure from the turbo on both sides of the blower, effectively stalling the blower. A stalled blower takes only mechanical effort to turn since it is doing no work, so you save the 10 or maybe 15 hp it would normally take to generate the 5 - 6 psi of boost that it normally produces. My engine, it needs all the boost it can get, other engines have different turbo's that create all the boost desired on their own so they can save some of the HP to turn the blower with the bypass. The blower is un-stalled at low rpm and during start-up, since the turbo doesn't do anything to speak of at those times, so the blower still creates the couple of PSI of boost to run the engine at idle and startup.
Many things to thing about with a turbo conversion. Hanging the turbo and running plumbing to it is perhaps the most obvious but not the least of the issues.
Brian
The air shut-down housing on my NA engine is wedge shaped -- left side 3 or 4 inches tall, right side ~1 inch tall. It appears to be torqued down onto the top of the blower by six bolts; I'm not able to see another row of tapped holes in the top of the blower. The air inlet hose is clamped onto a round fitting that's part of that housing -- rather than onto a seperate air inlet housing that bolts to the tall side of the air shut-down housing. figure 2 on page 3 of section 3.5.2 of the March '91 revision of the DD V71 service manual shows an intercooler equipped 12V71 with a pair of wedge-shaped air shut-down housing, each hooked to a seperately-cast side-mounted air inlet housing.
It maybe a revision manual in 1991 with a old illustration the 71 never used a air shut off since 1985 till they left the market in 1995
:-[ Sorry; it was a March '81 revision -- and page 3 of section 3.5.2 had "December 1980" on the bottom margin. ;D
I'm getting confused by advice about air horn or air intake tube diameters. Is the tube on a naturally aspirated air intake housing larger than the one on an intake that connects to a turbo? Can somebody tell me what the I.D. & O.D. are for the intake on a V71na and a V71TA?
Dimensions are "about", since the NA MC-5C intake left my hands about 4 years ago and the turbo intake is outside in the shed on the bus, and it's dark and cold out... NA 8V-71 in my MC5C had two 4" tubes from the air cleaners. Turbo intake has a 5" intake from the air cleaner and around a single 3" pressurized tube from the turbo to the blower top. NA engine had 4" exhaust from the manifolds to the Y-pipe into the exhaust, which was a 5" input to the muffler. The turbo exhaust is 3.5" from the manifold to the turbo and a 4.25" output (ish) from the turbo which is routed to the same 5" input to the muffler with a 5" pipe all the way.
The point is that Bernoulli's law says that increase in volume creates a reduction in velocity of an air flow. To keep the highest energy in the air intake and in the exhaust to the turbo, smaller tubes make the gas flow retain higher velocity and energy, resulting in higher boost. In a natural engine, large volumes reduce "friction" and let the air flow more freely, both on the intake and the exhaust.
So to summarize - NA engine had two 4" diameter tubes from air cleaner to blower, while the turbo engine has one 3" tube from the turbo to the blower. NA engine had 4" exhaust from manifold to the Y-pipe, and 5" into the muffler, while the turbo has 3.5" from the manifolds to the turbo, and 5" from the turbo to the muffler.
Brian