MFI tuning: space cam adjustment?

[majordad]

Could it be the Throttle Bodies ?

[RSTarga]

have you done a leak down test?
Checked Distributor advance curve?

[frederik]

Thanks, leak down test and distributor advance were both OK. What could be wrong with the throttle bodies? They don’t have excessive play and don’t seem to leak air.

[62S-R-S]

..Unfortunately, although he has lots of experience with MFI (Bosch, Kugelfischer, Spica, etc) and has modified Kugelfischer space cams, he has never modified a Bosch space cam before so it will be a first for him, and he doesn't think it will be ready before Spring 2024. The process he envisions is to take out the engine, put it on a dyno (which he owns), map it completely with the current space cam to find out exactly what modifications are needed, and CNC mill a new space cam based on that.

Anything we can try?

Obviously your car was intended to run with MFI, but with all the steps taken and gone through to this point, facing the prospect of an engine removal for quite a bit of time and trouble, that running some tests with Webers would provide a pretty good baseline on whether your engine is in good form or not.

[frederik]

It was actually running (un)reasonably well with a broken pump. Going to Webers… I don’t see myself doing that anytime soon since I specifically wanted the 2.2S experience. It’s only physics, we’ll get there eventually!

[frederik]

Update: it turned out that the exhaust -- while looking stock -- was actually from Ansa and the heat exchangers were an unknown brand (also looking stock). Replacing it with a Porsche Classic exhaust in combination with SSI heat exchangers made all the difference and finally she's running well! Hopefully this will help someone else in the future.

[SFE]

Amazing !
Thanks for the update

[edmayo]

Very interesting, thanks for the report. What led you to the exhaust? It appears that this came to you with that exhaust already on so you didn't get to notice the difference when all that was installed.

[cbpiii]

Curious, was the diameter smaller? What aspects of the exhaust setup differed from factory?

[frederik]

I think, different internals. From the outside it looks completely factory. If it were a dual-exit exhaust or something sporty, we would have suspected it immediately. I still have it and are planning to sell it (it sounds good) so I can take some pictures if anyone is interested.

Ed, it was on the car when I purchased it last year.