Why does British e30 appear to have more power?

[brahbarian]

http://www.e30zone.net/e30zonewiki/index.php/E30_Dyno_Graphs#M20

Ran into a discussion on another forum. I'm curious on why "british" e30 have a. Bit more power. Reading the other thread the op posted his Dyno number on a completely stock m20 and pulled a high of 145hp and 146 max torque.

[frankenbeemer]

Wheel HP or engine HP, that is the question.

[brahbarian]

Anyone familiar with these Dyno machines and how they measure hp?

[TSI]

No cats.

[jlevie]

An inertial chassis dyno is great for tuning, but not so good for absolute numbers. Different brands of dyno, ambient conditions, tires, how the car is placed on the dyno, and operator skill can all affect the numbers.

[redsubdivisions]

No cats.

[ELVA164]

Well, the Euro-spec cars had 9.7:1 compression and ran no catalytic converter. Also, in Britain, I've heard vague stories about a special "325iS" that was UK-only and had more power than a standard M20-powered car. Something about taxes and the M3 and a workaround....

[redlightpete]

It's actually surprising that almost a full point of compression yields such a small increase. It's like 3 hp more, right?

[digger]

Europeans use flywheel hp not whp.

basically depending on dyno type they take wheel hp and attempt to measure coastdown losses to give flywheel hp (can never be correct no matter what anyone tells you) or apply a fixed correction to whp to give flywheel hp.

dynodynamics apply ~20% correction when used to give flywheel numbers. dastek gives coastdown estimations

[digger]

the higher CR never made much more than the lower compression engines due to the tune not being as close to optimal according to some people in the UK.

the higher comp engines dont loses as much hp with age as the lower comp ones so they often dyno better but fresh vs fresh not much in it

[ForcedFirebird]

http://www.e30zone.net/e30zonewiki/i...yno_Graphs#M20

Ran into a discussion on another forum. I'm curious on why "british" e30 have a. Bit more power. Reading the other thread the op posted his Dyno number on a completely stock m20 and pulled a high of 145hp and 146 max torque.

Europeans use flywheel hp not whp.

basically depending on dyno type they take wheel hp and attempt to measure coastdown losses to give flywheel hp (can never be correct no matter what anyone tells you) or apply a fixed correction to whp to give flywheel hp.

dynodynamics apply ~20% correction when used to give flywheel numbers. dastek gives coastdown estimations

Those graphs clearly state BHP which would be at the crank (or a guesstimate as Digger said).

M20's with some mileage make mid-140's at the wheels with all stock equipment in place.

[digger]

some of the coastdown losses are wildly silly and why some garbage numbers are out there. you be struggle to find anyone who has had an M20 on an actual engine dyno

[ForcedFirebird]

you be struggle to find anyone who has had an M20 on an actual engine dyno

Would be neat, but not so many people care about the m20 as they do the chassis of the e30 - and now the 12v is a dying breed. Very fortunate to have a close chassis dyno with reasonable rates, thanks to them I have been able to compile quite a collection of graphs. I just bring a flash drive and save them all. Would be fun to make a single graph for them all, but the WinPEP program only allows 12 overlays and typical fine tuning takes several pulls for one car :(

[digger]

Same i know a place i just rock up to and they will usually have me on the dyno for a few power runs within an hr provided they arent in the middle of a full tune for another car.

collected my runs into a single PDF just recently got 22 pages worth of graphs and that's only the most significant ones with their latest windows interface

[ForcedFirebird]

Nice! My friend is more annoyed with the hook up. Some cars saw 50+ pulls. It's funny because if I make 3 pulls each on 2 cars, cost just as much as sitting for hours with one. Insurance requires him to hook the car up, then he hands me the brake release remote and keyboard for the PC and walks away to take care of other clients. Pretty much the same situation, as long as I go in off peak hours the rollers are open.