MatraSport Forum

General Matra related => Anders Dinsen's Weber Blog => Topic started by: Anders Dinsen on June 25, 2009, 11:04:10 pm

Title: On the rollers
Post by: Anders Dinsen on June 25, 2009, 11:04:10 pm
The scheduled rolling road session in April didn't work out, and then I found out that the rear shocks were gone, so I had to postpone it until they came back from refurbishment, but yesterday the 24th of June, it finally happened: I had the car on the rolling road with F. T. Tuning in Svedala near Malmö:


We spent about two hours mapping it, trying different jets, both in the idle (low speed) circuit, and the main circuit. It was too rich when we started, much better when we finished, but unfortunately we didn't have a small enough main jet to make it work perfectly, so this is only an intermediate result:


This cam should go far beyond 5000 rpm for max power, so the result of 130 hp on the top is not final at all. The max torque at 3300 is 198 Nm, and that is quite okay and 5% more than an S-cam is spec'ed at.

The jetting we have arrived at so far is

Mains: 140 (too large!)
Airs: 200
Emulsion tube: F9
Idle: 50F9

Ignition was advanced well beyond the 12 degree mark on the clutch housing.

Next step is to buy a set of new jets and do another session.


Title: Re: On the rollers
Post by: Jon Weywadt on June 28, 2009, 12:48:14 pm
Hi Anders.

That is a pretty serious tuning effort, but it appeals to my perfectionist side. Are you sure you are not a bit of one yourself?  ;)

Tell me how you arrange this, do you just call them up for an appointment, or do you have to "know" someone? Also, is it expensive? It sounds like you test it, change settings test again, etc. until you get it right. that could take all day, or ??? ???

Title: Re: On the rollers
Post by: Anders Dinsen on June 28, 2009, 08:43:29 pm
I think it's pretty much standard to set up the car on a rolling road if you're tuning the engine. Exception is for the few carburettor experts who prefer using ears and nose to do it, or if you're building a fuel injected system and fit a wide band lambda sensor in the exhaust.

On the rolling road you can run the engine at any revs under full load. In practice, he floored it at low revs and the let it slowly climb up to the max. The computers the measured the power output made by the engine.

I called Fredrik at F. T. Tuning for an appointment. Or rather, I sent him an e-mail. I've also been in touch with two other companies here in Denmark, but I ended up choosing the swedish solution because of the price, and it was also slightly closer to me.

It can take all day depending on how many parameters you want to play with. We only played with a few jets and the static ignition advance and it only took two hours including getting the car strapped down and measurement devices attached.

Yes, I am a perfectionist, but with my limited time, I try to focus on one thing at a time and also try to keep the project as simple as possible. I've spent countless hours on these carbs since I started fiddeling with them almost a year ago, but it's been fun all the way, and I'm now beginning to enjoy the result. It's very rewarding to have them running so well now. And also to be looking forward to perfection, which is just 'round the corner (so to speak).