dyno'd the 2.7i

[briansjacobs]

yes you can, but that's not what he was saying. he's saying you couldn't do it at 5000rpm.

well not without a 100 shot anyways;)

[nando]

yes you can, but that's not what he was saying. he's saying you couldn't do it at 5000rpm.

[briansjacobs]

you can make 205RWHP in a 2.8 without ITB's

You need 12.5 compression and larger valves and a nasty cam running on 100oct. We are seeing 190 RWHP out of a 2.5L with the same set up. I would imagine the car is undrivable on the street but it is a great race car.

[nando]

Torque/L is very closely related to volumetric efficiency

I came to this realization when learning about compressor maps. A torque curve is nearly the same thing as your engine's VE curve. more VE at a specific RPM = more torque = more power.


And yeah, it would be very hard to have that sort of VE at a low RPM. Especially with things like "OMG ITBS!!!111" that are meant for high RPM use...

[digger]

you guys missed the point of my post, i said that power at that rpm! Because a 2.7/2.8L M20 won't make that torque (on a dyno that reads sensibly, I laugh at some of the dynojet numbers i see).

Lets look at it this way assume its a 2.8L: 215wtq = say 250tq (assuming typical losses people claim!!!) which is near enough to 90ftlb/L look at some of the best tuned engines and do the same calculation (Torque/L). 911GT3 RS = 83ftlb/L; E46 M3 CSL = 84ft/L.

Torque/L is very closely related to volumetric efficiency

What this means is to make 205whp from a 2.8L you'd be making peak power at 6500-7000rpm almost certainly and not 5000rpm (2.8L aint enough cc's). I have no doubt you could make more than this but you need more rpm and to be still making torque in those high rpm.

[brody]

Built, tuned, cammed and with ITB's even?

I know that power can be made.

[nando]

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

that's about what my motor seems to like best.

[nando]

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.

what's the point of quoting reverse-calculated BHP #s at all? Just for bragging rights that your 150whp engine is "actually" 220bhp?

[ForcedFirebird]

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.

Built, tuned, cammed and with ITB's even?

[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%

[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.

[ForcedFirebird]

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

[Good & Tight]

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

[ForcedFirebird]

Quick vid of current AFR's

[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.