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911 Turbo (930) Forum 1975-1989

Turbo lag?

Old 08-08-2008, 10:56 PM
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lemonade
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Default Turbo lag?

I have a 1980 Euro Turbo with a freshly rebuilt 3.3 and SC cams with no other modifications.. The car pulls hard from low rpms, but never delivers the sudden hard, and temporary rush of power that I expected.

I have owned many turbo charged cars and my 930 seems oddly linear in the power delivery. What can I do (inexpensively) to compliment the SC cams and bring back the whooooshh?

I am not worried about huge horsepower I just want a harder hit from the horsepower I have. I hope the SC cams weren't a mistake.

Best,

David
CT
Old 08-08-2008, 11:18 PM
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Stratman
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K-27HF-S
Old 08-08-2008, 11:55 PM
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356-930
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Originally Posted by lemonade
The car pulls hard from low rpms, but never delivers the sudden hard, and temporary rush of power that I expected.
Stratman is correct in suggesting the K-27HF-S will add power to your engine but based on your above statement, a new/different turbo is most likely not the answer to your problem.
A 3.3 liter 930 with SC cams shouldn't pull hard from low rpm. These engines are dogs when not in boost. Near 3000 rpm, you should see a Huge gain in power, the 'rush' you expect. No 'rush', no or low boost. And the rush should not be temporary, it should stay to peak near 5,500 rpm and hold well beyond.
I suspect you have a major boost leak, defective turbo, timing issue, ignition issue, fuel issue or some combination of all. Time to instrument the engine so you can diagnose the problem.
Old 08-09-2008, 08:46 AM
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Vifa
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Turbo lag is great!
Old 08-09-2008, 09:53 AM
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lemonade
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By low rpm's I meant 3,000+. The turbo spools and the car pulls very hard. I am just looking for more turbo lag, I guess.

D
Old 08-09-2008, 10:29 AM
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Vifa
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I think it is hard to describe how much power you get from the Turbo. But, to describe what it feels like in my 965: it starts to kick in at 3000 +, yes, but I will not describe it as the car pulls very 'hard', but more like an ekstra power, and a more exponential increase of the acc.
Old 08-09-2008, 12:25 PM
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YYC930
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K27 HFS and 964 cams

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Old 08-09-2008, 01:59 PM
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356-930
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Originally Posted by lemonade
my 930 seems oddly linear in the power delivery.
I run a '79 3.3 liter, SC cam engine no intercooler and a smaller than the stock KKK-3LDZ turbo (Garrett GT3082R).
RWHP is linear from 100-hp @ 3000 rpm to 300-hp @ 6000 rpm.
Torque is non-linear, 170-ft lbs @ 3000 rpm, 230-ft lbs @ 3500 rpm, 240-ft lbs @ 5000, 255-ft lbs max.
If you sense power is linear, suspect a timing or fueling issue.
Old 08-09-2008, 07:25 PM
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Olli
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Agree with all of the above. In fact maybe I'd throw in the idea of swapping your exhaust headers as well so they are not the constricting factor.
But that's how one starts on that slippery slope. Next thing that happens is that you can't get your AFRs right and you blow your piston rings (ask how I know). Then you start hearing that little voice whispering EFI in your ear...and so it goes on....

I would vote for having someone diagnose your car for the issues 356-930 listed in post #3 before changing anything else.
Old 08-11-2008, 10:52 AM
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Arnies
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Obviously you have a grey market car. Does it have a cat added to be EPA certifiedf? If it has a cat check to see if it is clogged. Mine was and I had the exact same issue. Took the cat and hold on.


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