Pizza

Is the factory horse power and torque numbers from the crank or the rear wheels? My auto has 288 HP and 302 TQ from the factory. The 5-spd has the same. I'm assuming this is crank numbers. I noticed a Rennlister with Supercharged 312 RWHP. Doesn't seem like much increase for the money and the effort if the factory numbers are RWHP.

Thanks

hacker-pschorr

Starting in the mid 70's every car I know of was rated at the crank quoting net horse power.

IcemanG17

The factory HP numbers are from the crank and typically are SAE net numbers, not the old gross numbers of the muscle car era. Rear wheel HP is typically about 15% less for manuals and 17-20% less for automatics. So your car should be about 250rwhp, so a similar car with 312rwhp is a HUGE improvement!

Rob Roy

Factory numbers are at the crank. So if someone was putting down 312 hp at the wheels, using the commonly used factor of a 15% drivetrain loss, the car would be at approx. 367 hp at the crank

GoRideSno

Factory # are CHP.
RWHP for an 85-86 5 speed = 288X.85=244.8
RWHP for an 85-86 automatic = 288X.80=230.4
The car in question is a 5 speed. 312/.85= 367CHP (not other mods to this car at time of dyno) This car also does 4.9sec 0-60.
367CHP-288CHP = a gain of 79CHP at a cost of $3495.00. For $250 more it could be increased to around 400 CHP. For $1035.00 more it could be increased to 500CHP. The Jag/Eaton M112 system is the best (big) bang for the (big) bucks upgrade that can be done for a 32V 928.

Andy K

GlenL

The generally accepted fudge factors is that an automatic transmission loses 20% of the power and a manual transmission loses 15%. So your car can do about 230rwhp.

Also, Porsche numbers are quoted in DIN horsepower while American cars are given according to the SAE standards. for the same output, DIN is a bit, like 2%, higher. This can lead to horsepower angst.

Tres

Thats really kinda depressing when you have a 16 valve car like some of us do, and to think that you are not even putting 200 RWHP to the ground...... I need a SUPERMODEL.......HURRY ANDY!!!!!

Jim bailey - 928 International

Yes Tres ,the old very brown 1980 puts down 188-194 HP at the wheels about 220-225 ft lbs torque at the Streets of Willow it runs just fine. much to the embarrassment of a lot of other cars Andy Keel can attest to that !

Green Goblin

Then why call it bhp, which stand for brake horse power?????? Just wondering


Andy

GlenL

BHP is a term derived from engine dynomometers where the output is measured by a "brake."

Tres

Jim, This is true however when looking at what the newer 32 Valve cars put out it is kinda a low number. Even still, I do love my 81 and wouldnt trade it for the world. Besides I have put to much time into it to get rid of it, I now consider it as one of my children.

I just wish it had some more power to it like the Euro S does, 310 HP seems to make me feel all excited when I think of it.

I see my parts will be here tomorrow, thanks for sending them so fast.

Tres

Green Goblin

GlenL If you look in the owners manual it says BHP???????

Abby Normal

Who can do an engine dyno for a 928 motor?

Jim bailey - 928 International

I doubt anyone other than the Porsche factory has the engine management set up , fuel pump ,coils starter motor and fixture to hold the engine to run the engines outside of the car.

Pizza

Thanks for all of the replies. Andy I need a supercharger!

Thanks