rayfinkel

My question for the guru's here is what is in your opinion the maximum horse power and torque the 928 drive train can handle.

Also what would be the max for a daily driver.

For my car which is a 89 5 spd lsd.
also what would it be for a 77.

Also if you where going to increase the Hp and Tq would there be anything that you would beef up or replace.

thanks

89 928 5speed
77 928 5speed

hacker-pschorr

Depends on how you drive. I can break a 100% stock 928 at the drag strip if I wanted to

Two people in Green Bay have been pushing the limits for a couple of years now. Tim has a 5-speed car pusing over 550rwhp. He has tried very hard with drag radials to break something in the drivetrain. He is using a GTS transmission, the strongest 5-speed available for the 928. I'll go out on a limb here and say his next dyno day will yield 600+rwhp.

Down the road, Todd has an automic with over 640rwhp. So far no drivetrian issues to speak of. Todd will be over the 700rwhp very soon.

My 81 is making just over 400rwhp right now, so far so good with the drivetrain. The earlier transmissions are not a strong as the later ones (85+) so it will not suprise me if I pretzel this one.

If you are talking about a full out race car, all bets are off. Buy a few spares and learn how to rebuild the transmission.

mark kibort

i always get a little nervous when I select 1st on the race track!

5th always takes the beating of what ever the engine can produce, when you start doubling the forces on the drive shaft, i would get a little nervous. That poor 5th gear and input gear at the flywheel sure looks small to be handling 600ft-lbs of torque!

Im also wondering if the new generation of racing clutches are extra hard on the diveline as well. (shock loads)

mk

BIG 928

i have broke 3 early gearboxes fitted in my gts race car over the last two years. the gts boxes are definetly very strong and take a lot of abuse.

FlyingDog

How much money are you willing to throw at the car?John V broke his tranny (diff or pinion I think) the first time out in his 550rwhp/505rwtq race car and Mark A has broken a few GTS trannies. They aren't even the most powerful 928s out there. Nothing is bulletproof, but later parts are generally stronger.

shmark

Turning on the wayback machine, didn't DeVore's original ORR car put down over 700hp? I'm not sure if anyone has done it since. And where is that car today?

hacker-pschorr

atb

Any chance of posting pics of the '77 on another thread?

Vilhuer

I think DeVore engine had 709 hp, Kelly Moss has 711 in shelwed 944 racer. Factory had M28/70 twin turbo 750 hp boat engine in S4 back around '88. It was driven on the streets of Stuttgart. Then there was someone in Florida I think who had even more in turbo GT years ago when GT was almost new IIRR. 800+ or something like that and he went through several gearboxes and torque tubes.

AO

OK... what are you planing?

SwayBar

That is simply a fairy tale since no one has come forward with a dyno sheet backing up that 'claim'. So no, DeVore's car did not put down those numbers.

Brett928S2

Hi

For what its worth, my opinion is that the autobox will break at somewhere between 700 and 800 hp..

When I got to over 500 hp with my Nitrous system the autobox fluid started overheating and I had to change to Synthetic fluid...

Later this month I will hopefully have my new 1000 hp system fitted and once fitted I will SLOWLY increase hp through a controller....

So I may well be able to provide an exact listing of when 928 parts break....

Like.....750 hp autobox...850 hp,,,half shafts.....1200 hp....torque tube breaks...etc...etc

I will even be able to be pretty exact as I will know precise hp figures through the controller percentages..

To answer the second part of your question.....considering the handling on mine.....on a road car (not race) around 450 hp is around the maximum you would want....maybe 500 hp if you are feeling brave...anything more is suicidal....

All the best Brett

928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS,
KICKDOWN SWITCH - K&N FILTER - WIZARDS OF NOS - NITROUS KIT 150 HP - 505 HP/500 FT LBS TORQUE -
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

hacker-pschorr

The Kelly-Moss numbers are from their engine dyno, not rear wheel. It was never quite "finished". I see the car form time to time when I'm in Madison.

FlyingDog

Isn't that the engine that's in Tim's ORR car? I thought there was mention of it being the same engine converted from 16V to 32V.

IcemanG17

No.....Tim has the later motor from the Devek white car that went 209-210mph back in 1999......his motor makes more power now then it did back then too.......

the highest dyno recently is Todd's supercharged stand alone EFI 928 with over 600whp......the highest normally aspirated is Louie Otts at 584whp 6.5L stroker....I'm sure the records will be broken by a substantial margin this year....

the question of how much power can a given tranny handle.....all comes down to

"for how long"....for a short dyno run....almost any tranny will last....but for repeated laps of the racetrack like Anderson-Fan-Veniger with their strokers....even GTS trannies don't last that long....clutches are another issue.....once above about 450ftlbs all of the stock clutches will not last long either......but there are several stronger clutches out there....