3.2 Dyno Day at Weltmeister Silverstone NOW MOVED to 20th August

IanHighfield · Sep 14, 2005

Ordered my custom chip today, so will be ready for the next dyno day.

SW says it should make 5+ extra BHP and lots of improved throttle response - cannot wait !

Guest · Sep 14, 2005

Ian,

You are becoming obsesses with horsepower !

IanHighfield · Sep 14, 2005

Richard,

I can understand BHP. It is AFR I haven't a clue about.

Can you decipher in simple terms what LAMBDA is for me :-

Guest · Sep 15, 2005

I think SW explained it pretty well. The lambda is just another way of showing the air-fuel ratio. So your lambda is about 0.75-0.80 which equates to 11.2-11.8:1 AFR.. This indicates that you are a little rich. For max hp you want to be stoichometric (spelling?) which is essentially the 12.8-13.1:1 that SW refers to. Its pretty simple really, too lean or too rich and you don't make all the hp you could be making. However, you really want to be a tiny bit rich rather than a tiny bit lean in order to allow a little leeway for lower octane fuel. This is why your std chip is programmed to be a little rich when you are under load from 4000rpm up. As insurance for when you have to put something less than Optimax in the car, you could always keep a bottle of octane booster in the car.

RB

Steve Murley · Sep 15, 2005

Hi Richard B,
I would appreciate your diagnosis of my AFR reading, I was told it was rich at the top end, Its looks richer at lower revs to me though.
Comparing with Ian Highield's AFR reading graph, his S_HP figures (eg 120.0) on the left side vertical relates to LMBDA figure of 0.8 on right side vertical, on mine, 160.0 relates to 0.8, do you know why this is different.

Cheers

Steve

ClubSport 911 · Sep 15, 2005

Steve - the graphs are both correct. - don;t worry about trying to tie up the HP / AFR because if you look at Ian's plot, he has a different scale to your on the HP axis anyway !.

The HP and Lambda do not need to be read together...what is important is the relationship with engine RPM and Lambda.

Your car is definately rich at the higher RPM's - the graph shows a decline in the AFR, so that means for a given amount of fuel, you have less air. This is "rich". Actually - engines rarely run at Lambda = 1, but for most power you need to be slightly rich 0.88 - 0.9, and this is where Steve Wong tends to drive his chips.

Guest · Sep 16, 2005

Steve - Steve D beat me to it. Your lambda curve looks a lot like Ian's. As SW says with regards to Ian's car, there is maybe 5hp left on the table. Nice to have but less than you can feel with the old butt-dyno. Maybe he can get you more part throttle and midrange as well which would be more noticeable.

Steve Murley · Sep 16, 2005

Steve D and Richard B,

Thanks very much for your input, SW chip is something to think about for the future.

Cheers

Steve

ClubSport 911 · Sep 19, 2005

What exhaust system you going for?

Hi Shirish.

Well, I have been in discussion with a bunch of folks about exhaust tuning and have the aim of working out which ones work best on the 3.2 motor.

Although an old engine, the 3.2 does respond to some tweeks, but not in the radical way some advetising might have you believe. [

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I'm not going to promote one co. against another until I have the data to support that recommendation - sure you understand why.

Please PM me if you are interested in following the debate

Kind Rgds

STEVE