924Board.org

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Hi all,

I always felt that my 924 turbo has a slowish throttle response. What I mean is the engine doesn't rev up very fast, even in neutral. And there seems to be some sort of delay when you first press on the accelerator, and again at ~3000rpm. In contrast I remember testing a 911 (964) which would spin up like crazy.

Is it all down to the engine design (eg. 6cyl vs 4 cyls) or is it because of the EFI/engine management?

I'm actually wondering if the engine response will improve if I convert it to EFI. Can anyone who has done the conversion share your experience with it?

Thanks!

[flosho]

I believe EFI will improve throttle response a noticable amount. It will also be smoother as well.
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[This Space For Rent]

[Smoothie]

It's tough to tell from here if what you're experiencing is abnormal for a 931. If it is, it could be a timing, vacuum leak, or A:F mix problem. What's your vacuum reading at idle? -And what's the model year?
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Min]

[endwrench]

Your ignition advance curve has a lot to do with also.

Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!....

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Thanks for your replies guys!

Smoothie,
My car (its a series 1 1980 ROW model) runs well as far as I know. My vacuum at idle is ~18inHg. I have no problems starting, engine pulls well through the rpms except my turbo isn't at its best, full boost comes in above 3000rpm. Only recently installed a wideband AF gauge so still learning how it behaves. It idles ~13.8-14ish and normally stays within 12 and 15 during driving except for initial throttle input. The only thing I've never been happy about (other than the transmission) it is that the response is somewhat slow compared to the newer cars. I figured its because of the mechanical metering of the fuel. The fuel only gets metered after the throttle (input) is given and the air starts to flow in, hence the delay. Am I correct on this?

Todd,
I've never fully appreciated the potential of digital ignition. Always thought that a distributor was enough...as long as the spark happens "around there". Does it really make all the difference?

I've been having second thoughts about my 924 and this EFI project as I've recently got a newer car (a Volvo S60 T5) and its so nice to drive! The power delivery is addictive! But I still love the way the 924 handles! Do you think an old engine can ever be tuned to spin like a new one?

[Smoothie]

I usually see 20"hg at idle, but I don't know - maybe splitting hairs with that.. 18"hg is more in line with what most others report.
Yes, there's some delay inherent in the CIS design, but I don't have the same slowish throttle response problem you have - maybe just because I don't drive any newer cars. I say don't drive newer cars and the problem disappears.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Rasta Monsta]

I think you should consider refreshing every piece of rubber in your intake. My car had similar issues which I eventually concluded were related to vacuum/boost leaks - the before and after difference after the refresh was huge, and many of the rubber joints and hoses didn't show any visible problems until they were in my hand and I could really look closely at them.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

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