'87 325e - 327i Dyno results

[JA1991]

Wow soo good, i can't wait to do a head swap.

[/quote]

[nando]

nice! actually, that's one of the better HP/torque curves i've seen from a 2.7/head swap. perhaps the 323i head is a better match than the 885 to the flat-topped pistons - those always end up being a bit down on power compared to a stock M20B25, just more torque. yours is about dead even on power and definitely more torque.

~178HP @ Crank

Very respectable.

I'm donig an 885 head onto an 86 325e bottom end. Thinking of building the head up some, to get ~ 200HP @ crank ideally.

what the hell sort of drivetrain loss are you using? there's no way it's 178bhp.

[nando]

After planning this conversion for a year, I just had to see what the final results were. Wish a baseline 325e pull had happened, but from what I can find, looks like about 75-80 rwp? Is there a common formula for our cars to roughly determine crank output from rwp? I guessed seat of pants, a 60hp increase over the eta.

stock eta should be more like 105-110bhp, not 80..

here's one that put down 112whp at 3900rpm:


it's definitely a big improvement over a stock eta, but it's certainly not a 60hp increase.

[Gary Horneck]

Just going by the few assorted youtube videos showing a 325e on a dyno. Still think it was worth the conversion. Amazing that a 121hp engine only lost 9hp in frictional losses though.

[nando]

it was probably underrated like many BMW engines

anyway, even if you use a pretty standard HP loss (~15%) it still ends up at ~105whp.

[rodpaine]

it was probably underrated like many BMW engines
anyway, even if you use a pretty standard HP loss (~15%) it still ends up at ~105whp.

Yup, my stock 1983 528e freshly tuned produced the following on the York Automotive dyno in Mt. Airy, MD:

- 106.5 RWHP with stock ECU
- 122.3 RWHP with E.A.T chip

I talk about involving various ECU chips here and my experience with chips on other M20 engines in poor states of tune.
-Rod

[e30trooper]

Just going by the few assorted youtube videos showing a 325e on a dyno. Still think it was worth the conversion. Amazing that a 121hp engine only lost 9hp in frictional losses though.

LOL that was my old eta
Had 88 rwhp @ 4950 rpms , no chip just cone filter and cheap axle back muffler. Had tons a intake leaks. This was 3rd gear pulls
This dyno read low #s so maybe on others might be around 95ish whp

[iXe<30]

ok ill be that guy.... how does this effect the awesome efficiency of the eta.... you guys probaby are having to much fun to care but im interested in a stroker for my ix esp if i can get better mpg and keep similar power/more torque.

[e30trooper]

With the 2.93 i still get great MPG. Even with the 2.93 the car still flys, however there's plenty of room for improvement

1st and 2nd gear pull , eta block with refreshed/decked 885 head full 1.3 swap , ebay b3 chip copy. open 2.93 diff

[iXe<30]

[quote=e30trooper;3232318]With the 2.93 i still get great MPG. Even with the 2.93 the car still flys, however there's plenty of room for improvement

1st and 2nd gear pull , eta block with refreshed/decked 885 head full 1.3 swap , ebay b3 chip copy. open 2.93 diff


cool thanks man. any approx numbers for gas mileage?

[e30trooper]

[QUOTE=iXe<30;3232499]

With the 2.93 i still get great MPG. Even with the 2.93 the car still flys, however there's plenty of room for improvement

1st and 2nd gear pull , eta block with refreshed/decked 885 head full 1.3 swap , ebay b3 chip copy. open 2.93 diff


cool thanks man. any approx numbers for gas mileage?

no idea, my odo. doesn't work

[iXe<30]

bummer.... i think im gona go ahead with this instead of pulling my i motor for a refresh. thanks for the thread guys. Anyone close to pa have an eta block fs?...

Edit: woah sorry for the thread jack ill stop now..

[ÜberslowETA]

This is great to hear! I have been staring at a complete lot of parts for a 731 head based swap. Im feelin motivated to jump on it.

OP...did you ever consider 19# injectors or an MAF?

[Gary Horneck]

Two AutoX's later, and making quite an impression on the Street Prepared class. I now run in DSP, and have taken class twice, and a FTD in SP Sunday. Second run of the day on Sunday...

[e30trooper]

A small update on my car. Installed a 3.73 lsd last week and tracked the car on Sunday.

WOW , after all that work and then installing a proper gear ratio the car pulls great. With all season tires I can chirp 3rd gear all day long. On the track I couldn't get grip due to the tires. However on a uphill pull ( top of 2nd and mid 3rd gear ) i pulled about a car and half on a s2k. So mid range power is where its at. Im lovin it!