low dyno numbers

[CorvallisBMW]

I recently did some dyno runs on my '88 325iS, 204K miles. I have new injectors, plugs, wires, cap & rotor, exhaust including cat, basically everything on the outside of the motor. They did A/F during the runs, and it was damn near perfect. Yet i only got 108 whp and 110 wtq. Accounting for a 25% driveline loss, that's 135 crank hp, 30 below where it should be. Any ideas? this really sucks!!!!

Darin

[Jarvis]

Re: low dyno numbers

I recently did some dyno runs on my '88 325iS, 204K miles. I have new injectors, plugs, wires, cap & rotor, exhaust including cat, basically everything on the outside of the motor. They did A/F during the runs, and it was damn near perfect. Yet i only got 108 whp and 110 wtq. Accounting for a 25% driveline loss, that's 135 crank hp, 30 below where it should be. Any ideas? this really sucks!!!!

Darin

Actually it's probably worse than you think...
25% driveline loss? Maybe in an AWD automatic. Figure 15% for stick, 20% for automatic in an E30.

[CorvallisBMW]

reallly, only 15%? shit, that means 125 crank hp. WTF?!?!? please help me get to the bottom of this!

[CorvallisBMW]

btw, compression test came up 165-165-163-173-165-165. And burns almost no oil, less than 1 quart synthetic between changes.

[RobertK]

Are you absolutely sure it's an iS and not an eta?

[CorvallisBMW]

Yes, positive.

[gstuning]

Yes, positive.

What where comparative numbers from other cars getting dyno runs?

[CorvallisBMW]

on that same dyno, you mean? well, i can't remember exactly, but a turbo E30 325i on 7lbs boost got 153 whp and 224 wtq, and a euro motor Z3 M got around 300 whp. But they didn't happen while i was there, i heard those through word of mouth. So they could be totally off. When i drove an auto iX that belonged to a friend of mine, it felt a little slower than mine, and it was in impeccable shape at only 75K miles. I wish i had driven more e30's to compare it too, but i havn't. Could operator or dyno error really account for a 50 hp loss? i figure with the chip, this engine should be making around 170-175 at the crank.

[UNHCLL]

Its not operator error.

Every Dyno reads differently. Dyno numbers are worthless anyways, they are only good for e-bragging and arguments.


And no, you arent making 175 crank with a chip.
200k+ M20... no surprise its low.

[Digitalwave]

With a 200k M20 and a chip I would wager you are still making less than stock factory HP, although 108whp is a joke. And 153whp for a 7psi turbo is very low too, I have seen stock M20s make that but just like Chris said the numbers mean nothing and can't really be compared.

[CorvallisBMW]

well, like i said, those were numbers i heard through word of mouth. no telling if they are actually right. I guess what i need is a seasoned e30 expert to drive my car and tell me if it feels like 165 hp or 108 hp.

[DarkWing6]

or look in the want ads and call up a few people and test drive a few cars. test what you feel in those and compare them to each other and your car. fun and informative.

[Mystikal]

Grab a friend with a stopwatch, do a rolling 5-60 run. Should be ~8-8.5 if your car is healthy.

[CorvallisBMW]

not a bad idea to do the rolling test. maybe a dyno run on a different dyno at a different place would produce better results, if the one i was on was all wacked?

[Mystikal]

Dynos are for relative tuning, not comparing with internet stories.