My M20B25 running the ole 1320.

[rwh11385]

1990 325is, JC Chip, M30AFM, 19#. 142.7rwhp, 143rwtq. 1245XX miles.
No spare, no jack, no trunk pad covering spare.
1/2 tank of gas, pretty cleaned out car.
Rough guibo, treading dwindling 195/65-14 tires on stock 'weaves.

First time drag racing......possibly last time, in this car.

[cahomey]

1990 325is, JC Chip, M30AFM, 19#. 142.7rwhp, 143rwtq. 1245XX miles.

Im confused. Didn't Chapels stock m20 with only a chip and 200xxx+ miles get 148rwhp on a dyno a while back?

[Jand3rson]

142 rwhp? 148 rwhp?

That seems pretty low for a 325i. Why such low numbers?

[rwh11385]

1990 325is, JC Chip, M30AFM, 19#. 142.7rwhp, 143rwtq. 1245XX miles.

Im confused. Didn't Chapels stock m20 with only a chip and 200xxx+ miles get 148rwhp on a dyno a while back?

Every engine is different. So comparisons are going to be pretty much worthless.

Plus, it was 80 degress and 80% humidity on my dyno day. They may have been different types of dynos, too.

But that is what the computer said when my runs were done. 142.7rwhp.

[Stu]

142 rwhp? 148 rwhp?

That seems pretty low for a 325i. Why such low numbers?

Both of those numbers are over 170 crank horsepower (assuming a Dynojet). 325i was rated at just under 170.

You don't use dyno numbers to evaluate a cars performance, do you?

[Jand3rson]

Both of those numbers are over 170 crank horsepower (assuming a Dynojet). 325i was rated at just under 170.

You don't use dyno numbers to evaluate a cars performance, do you?

OK... I don't know how it works exactly.

Maybe you should explain it to me, rather than making me feel stupid about it.

[Skafrog]

And the tables are turned ;-)

[E30godz]

hell i made 135

[rwh11385]

Well, Spaz made 15.5sec quarter on a completely stock 325 or was it 325is.
I made 15.6, so maybe his car was better.......or he had less gas in it.
or maybe it was a different year and lighter.....or the climate was different, or he just had a lower R/T. If I shorted my reaction by .2 sec, I would have done much better, but first time at the drags.

Just take my dyno runs for what they are, a dyno of MY engine, and no one else's. ;)

[e30Matt]

Yeah, the only dyno I care about in my car is the butt dyno. Prolly cause if I took it to a real dyno, I'd be embarassed by the low number.

[BS87]

Hell, my old eta is so beat up, i'd be surprised if it still had triple digit rwhp. But it's good on gas and the torque is nice ;)

[Rob]

[quote="Stu Mc"]

You don't use dyno numbers to evaluate a cars performance, do you?

unfortunately, this gem of information has been all but lost. Dyno's are a tuning device, not a drag strip. Their main purpose is to evaluate individual engine performance for tuning purposes, not performance purposes. There are so many variables that affect dyno numbers, ambient temperature, elevation, etc, etc, etc, that comparing dyno numbers is inaccurate to say the least. A car may put down peak numbers that differ by 10rwhp on the same day on two different dyno locations, even if the dyno is the same brand.


Besides, peak numbers are truly useless, that 142whp e30 is gonna be a lot faster than a 142whp civic (in most cases), even the they "have the same horsepower" , its all about area under the curve.



back on topic, good numbers for a ~15 year old car built for turns!

[cheades]

When I put mine on the dyno I got like 139.x with a JC chip, intake, and exhaust with 165k miles on the car. Rob is definitely right about area under the curve and the other thing is look at how flat the torque curve is.

[KenC]

Both of those numbers are over 170 crank horsepower (assuming a Dynojet). 325i was rated at just under 170.

You don't use dyno numbers to evaluate a cars performance, do you?

OK... I don't know how it works exactly.

Maybe you should explain it to me, rather than making me feel stupid about it.

The 168hp rating of the M20b25 is hp at the crank. But that hp from the crank has to be transfered through the transmission, down the driveshaft, into the rear differential, and out to the wheels. Along the way you'll lose ~30hp or so. Thus 142 rear-wheel horsepower, is roughly 172 bhp (higher than the stock rating from the factory).

[Spaz]

Well, Spaz made 15.5sec quarter on a completely stock 325 or was it 325is.
I made 15.6, so maybe his car was better.......or he had less gas in it.
or maybe it was a different year and lighter.....or the climate was different, or he just had a lower R/T. If I shorted my reaction by .2 sec, I would have done much better, but first time at the drags.

Just take my dyno runs for what they are, a dyno of MY engine, and no one else's. ;)

i alwasy race with a half tank of gas.....best mix between traction gain and weight....here is my spec sheet

R/T... .655
60... 2.282
330... 6.505
1/8... 9.982
MPH... 71.31
1000... 12.965
1/4... 15.511
MPH... 88.81

edit:

Car mod's:

stock height
no spare tire, jack, wheel chock, or trunk linning.
on stock weaves with 195/60/r14 toyo proxes tpt about 25 psi
kn filter (drop in)

having a lowered car will slow you down drasticly