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Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 11:32 am
by clarko74
I've always been keen to find out how many horses my 325 has left after 22 years and 180k miles so yesterday I finally took it down to Surrey Rolling Road and had it dyno'ed. The only modification that's been done to it is the addition of an A-Tech chip. Here's the graph:
Considering the chip should give an improvement of 8-14hp, it looks like it's lost a few horses, not a bad preformance though. Charlie at Surrey Rolling Road said that m20's often lose many more than that and thought it was a pretty good effort.
All was going well until the final run on the rollers when there was an odd noise from under the bonnet. Charlie stopped the car and we investigated, it turned out the alternator belt had snapped

. Spent the rest of the day waiting to be recovered then being towed home. Charlie's a top bloke though and I highly recommend Surrey Rolling Road.
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 11:39 am
by pnd
cheers for posting these are always interesting but what was peak torque and is it a high or low compression 2.5?
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 11:53 am
by Jesus325iTouring
Pretty good result IMO,my original 230,000+ engine was running 130bhp

My replacement engine (out of a 525i) is from memory about 165bhp at about 150,000.Both later low comp motors.
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 12:22 pm
by darren1200
I took my e30 3.5 M30 conversion up there about 3 weeks ago, with a loads of 500/600hp toyota supras
It made 199.9bhp lol couldn't get it over 200 and 210 torque!
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 12:27 pm
by gareth
0.1bph off the magic figure? how frustrating!

Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 12:32 pm
by E30Gheko
How much did it cost u to get it on the rollers if u don't mind me asking?
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 4:07 pm
by clarko74
It's a high comp early engine. I didn't get a figure for the torque but from the graph it looks like about 172lbft @ 4300.
There were a couple of really beefed up new mustangs that were done just before mine, I don't know what power they were putting down but they sounded fierce.
Cost is £50, their website is here:
http://www.surreyrollingroad.co.uk/
Re: Dyno'ed my 325 yesterday
Posted: Sun May 24, 2009 4:19 pm
by E30Gheko
Cheers! It's a bit far away but I wanted a ball park figure.
Found a local one so I'll give em a call Tuesday.

Re: Dyno'ed my 325 yesterday
Posted: Mon May 25, 2009 10:30 am
by pnd
[quote="clarko74"]It's a high comp early engine. I didn't get a figure for the torque but from the graph it looks like about 172lbft @ 4300.
THATS INTERESTING a high comp early engine should do 170 + but your torque is up i have suspected for a while that the a tec chip gains torque but looses absolute power at the top end your graph goes some way to confirming this.
Re: Dyno'ed my 325 yesterday
Posted: Mon May 25, 2009 12:39 pm
by bss325i
Thats not a bad result Adrian for the mileage anyway.
I have also had mine on surrey rolling roads dyno so for comparison, my sport with 51000 (at the time) miles and a low comp B25 with the only mod being a BTB2 manifold and scoprion

exhaust made this,
182bhp and over 185lbft
The same day i drove up to Evolve in luton and it did this,
185bhp and over 190lbft.
I put the diference down to Evolve having a bigger fan. The both use DynoDanamics dynos.