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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: CrabbyMilton on September 11, 2015, 05:08:06 AM

Title: RTS 8V-71 vs. 6V-62 question
Post by: CrabbyMilton on September 11, 2015, 05:08:06 AM
Back in the '80's yours truly rode on many RTS's when MCTS(Milwaukee) had 150 of them. 144 of them had the 8V-71 while 6 had the 6V-92TA both will the V730. I noticed that the 6V-92 versions shifted out of first much quicker than their 8V-71 partners. Was this to due to more HP and torque from one of the engines? They both seemed to both have about the same acceleration. These buses were 1980 model years and were I think among the last to have the 8V-71's and a few of the first with the 6V-92 transit version otherwise the buses were identical.
Title: Re: RTS 8V-71 vs. 6V-62 question
Post by: Bill Gerrie on September 12, 2015, 11:25:15 AM
There is two different torque convertors available for the V730. You would need the transmission part numbers to know the difference. One is 2.51 to 1 and the other is a 3.25 to 1.
Title: Re: RTS 8V-71 vs. 6V-62 question
Post by: CrabbyMilton on September 13, 2015, 08:52:44 AM
I should have worded it better but what were the HP and torque ratings for those two engines for transits back then? I know the 6V-92 from what I saw was 253HP but I don't know the ratings of the 8V-71. I forgot that there were different torque converters available for the V730.
Title: Re: RTS 8V-71 vs. 6V-62 question
Post by: TomC on September 13, 2015, 10:43:20 AM
8V-71 used either N60 injectors (280hp @ 740lb/ft torque) or N55 injectors (257hp @ 680lb/ft torque).

I don't know about the way they shifted, but with my 8V-71 turbo with 7G75 injectors (375hp @ 1125lb/ft torque), my V-730 will shift at 1600rpm on partial throttle (going down to 1,100rpm) or at 1950rpm on full shifts. Turbocharging with air to air intercooling REALLY wakes up the 8V-71. I have been very pleased with my performance. While the fuel mileage is about the same (5-6), the performance and lack of black smoke pulling a hill is well worth it. Good Luck, TomC