dyno'd the 2.7i

[briansjacobs]

Physics does not lie.

physics do not lie, but statics do!

[nando]

all I'm saying is if the e30 has a 28% drivetrain loss, and my ix is even higher with the awd, my m20 must be making more at the crank than most built S52s (which I know it doesn't, not by a longshot).

[LowR3V'in]

When I first got into cars, I'd see dynos that were pretty amazing
compared to dynos here in the US.
"This guy is making 120hp in the uk with his 2.0 VW, wow!"

Then I learned they convert to brittish horse power, and that's why they
ran slower times with "bigger" numbers. Just rambling don't mind me

Also wondering what is the acceptable rang of drivetrain loss for our cars
and what is it based on (who tested and what did he test?).

Do heavy wheels play into this?

If it does, does this mean I can get more HP from a chassis dyno if I just got lighter wheels (same size tire/rim)?
Same with lighter flywheel. More HP at the chassis dyno?

[nando]

the only real way to know would be to dyno an engine on an engine dyno and get a directly flywheel #, and then dyno the same engine in a car on a chassis dyno, which eta said.

the thing is - at the end of the day, the only thing that really matters is wheel horsepower, and how fast your car goes (or doesn't go) down a track.

[LowR3V'in]

I think the same.
Inflating your numbers with fake made up drivetrain % loss
to Brittish HorsePower is bull shit, and just a big guess.

[StereoInstaller1]

Then I learned they convert to brittish horse power

Uh, no.

BHP is short for Boiler Horse Power, Brake HP or British HP...but British is the same as US.

Check it: http://en.wikipedia.org/wiki/Horsepower

[nando]

I think the same.
Inflating your numbers with fake made up drivetrain % loss
to Brittish HorsePower is bull shit, and just a big guess.

lol

[clarkson]

My stock M20B25

Hi guys, new here, just came across this thread and it is interesting to see modified M20's (ok using basically a mix and match of stock BMW parts) and what they are doing on a dyno. I just bought a 1988 325i manual coupe, and went through it back to front with a big service incl dist. cap, rotor button, timing belt, waterpump, radiator, all the hoses and the usual service stuff too. Plus a rebuild 3.91 LSD. And then it was down to the local dyno for five runs using premium fuel.
I bought the car after looking for 6 months, it is incredibly original and never been modified in any way. It has 190,000 kms and has had mainly dealer servicing. Attached is the dyno result. The first run produced 138hp ATW, and the second from last run produced the attached 146hp ATW. So from I can gather, you have to be careful not to backwards when modifying these engines. To me, a lot has to do with the compression ratio and pistons. The ETA engine was always originally designed as a high torque economy engine.
The ETA crank can be used, but the best result is with custom pistons. A friend has just done a run in dyno at 5000 rpm producing 205hp ATW, using the ETA crank, 11.1 JE pistons, and a baby Schrick cam, and stock computer and intake.

http://www.r3vlimited.com/board/attachment.php?attachmentid=33118&stc=1&d=1284891195

[ForcedFirebird]

Well borrowed a wbo2 stand alone from a friend to get the fueling dialed in after my guage took a crap. WOW! Is all I can say. The 2.7i seems to like it a little leaner than I'm used to, got the AFR nailed at 12.8 WOT and mid 14's for idle and cruise. Gave it a couple more degrees of advance on the whole map (up from what we already had) and this car scoots now - still conservative compared to the turbo maps in the sticky, though. Can't wait to get back to the dyno and see what the tuning did to gather numbers. While there I will flash the stock tune for one of the pulls to show a back-to-back comparison. :D

Also started on the headers, once they are finished, the car will get yet another tune, then back to back results again, stock tune and my tune.

[eta]

Sorry to resurect old post but I have not looked here for a while. Those folks who are talking about british horesepower numbers had better read my post a bit more carefully.

I clearly say that wheel horsepower is real and all the sum I do are based on that. My comments about drive train loss are estimates and I clearly say that are their basis. Nowhere do I inflate any numbers. The basis for drivetrain loss may be shakey, I admitted that already but at least the number has a basis. The other drivetrain loss numbers quoted have no reference quoted, they are mearly the same information that I have seen quoted elsewhere repeated again, again without basis. Is that real???? If the 28% turns out to be wrong so what. I use wheel numbers anyway.

I do get the feeling that I post, those posts are read but only half of what I say is taken in and the posts are made slating my posts but if the whole of my post was read then those comments above would be seen to be without justifyable basis.

I give up on here.

[ForcedFirebird]

Quick vid of current AFR's

[Good & Tight]

Nice solid afr's John! Lean is mean though, have you tried leaning it out a bit?

[ForcedFirebird]

Not really. It seems to really like mid to high 12's at WOT.

[digger]

Hi guys, new here, just came across this thread and it is interesting to see modified M20's (ok using basically a mix and match of stock BMW parts) and what they are doing on a dyno. I just bought a 1988 325i manual coupe, and went through it back to front with a big service incl dist. cap, rotor button, timing belt, waterpump, radiator, all the hoses and the usual service stuff too. Plus a rebuild 3.91 LSD. And then it was down to the local dyno for five runs using premium fuel.
I bought the car after looking for 6 months, it is incredibly original and never been modified in any way. It has 190,000 kms and has had mainly dealer servicing. Attached is the dyno result. The first run produced 138hp ATW, and the second from last run produced the attached 146hp ATW. So from I can gather, you have to be careful not to backwards when modifying these engines. To me, a lot has to do with the compression ratio and pistons. The ETA engine was always originally designed as a high torque economy engine.
The ETA crank can be used, but the best result is with custom pistons. A friend has just done a run in dyno at 5000 rpm producing 205hp ATW, using the ETA crank, 11.1 JE pistons, and a baby Schrick cam, and stock computer and intake.

http://www.r3vlimited.com/board/atta...1&d=1284891195

I highly doubt that a 2.7/2.8 M20 can make 205whp @ 5000rpm, that works out to be 215wtq and is waht S50/S52 with 3L+ make.

[digger]

Sorry to resurect old post but I have not looked here for a while. Those folks who are talking about british horesepower numbers had better read my post a bit more carefully.

I clearly say that wheel horsepower is real and all the sum I do are based on that. My comments about drive train loss are estimates and I clearly say that are their basis. Nowhere do I inflate any numbers. The basis for drivetrain loss may be shakey, I admitted that already but at least the number has a basis. The other drivetrain loss numbers quoted have no reference quoted, they are mearly the same information that I have seen quoted elsewhere repeated again, again without basis. Is that real???? If the 28% turns out to be wrong so what. I use wheel numbers anyway.

I do get the feeling that I post, those posts are read but only half of what I say is taken in and the posts are made slating my posts but if the whole of my post was read then those comments above would be seen to be without justifyable basis.

I give up on here.

15-20% mark would justified by data from newer vehicles where the BHP is actually known. Different machines produce different results. On a Dyno dynamics it is about 20%