924Board.org

[der uber]

Would a very small vacuum leak become more noticable under hard accelleration?

Sometimes when I push around 3500-4000rpm I get a small but noticeable power loss but everything fires. Seems like the fuel cuts back some. But it otherwise rides great - it is just when I "get on it." and doesn't always do it.

Everything I have read so far is all about vacuum.

I plan to replace the fuel filter once the part arrives, since it woudn't hurt to replace that anyway.

PO rebuilt the car with a non turbo motor. There is nothing else special or upgraded about the engine or other areas of the vehicle.
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1980 931 converted to n/a
My first project

[Rasta Monsta]

[Ozzie]

Check your timing and your distributor.
My vacuum advance diaphragm was shot and a spring was off the centrifugal advance- making both incorrect or inoperative.
Ended up replacing the whole lot.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[Rasta Monsta]

Here's a cheap dist on Ebay. . .
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[bruce76-924]

Double check your ignition leads, my old car had a power drop under hard acceleration and I traced it to bad leads. You can see if they are arcing out if you look at them in the dark, if they are bad you get pretty sparks dancing around the engine bay!!
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1976 924 LHD, full cage, semi tube chassis, 951 brakes, lightweight 951 body panels.
1.8t engine conversion with Holset turbo and 6 speed Audi gearbox.

[der uber]

Awesome - I will check those areas out.
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1980 931 converted to n/a
My first project

[gohim]

A small vacuum leak would not become more evident at 3500-4000rpm.

An pressurize intake or an exhaust leak would. You could have a broken or missing fastener/s in the pressurized track between the turbo output and cylinder head, OR an exhaust leak between the cylinder head, and turbo.

It is very common for the 931s to lose fasteners in the turbo piping, and leak pressure, causing a loss of hp.

[Rasta Monsta]

Gohim, its a 931 converted to N/A.

(*thud*) <- gohim fainting
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[gohim]

thud is right....

why does he still call it a turbo?

[der uber]

I still call it a turbo because I'm literally an idiot about this. I ask sincerely and humbly... what would you recommend as my description.

Should Turbo not even be in there at all?

[D Hook]

I'd love to see pics of the engine and see how he did the that.

Is the fuel distributor still on the passenger side? (LHD)

I'd look hard at the distributor. Sounds like that might be the culprit.
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'80 924 n/a SOLD

[der uber]

Sounds like some real consensus on the distributor. I will post pics asap, this evening at the earliest. I'm thinking of doing an animated gif of the engine and exterior, a la ideola.
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1980 931 converted to n/a
My first project

[!tom]

Sounds like fuel filter to me.

A couple months ago, mine was running fine, except it would sometimes have a bit of a miss when cold right after starting. I figured that was due to a weak spark, so I replaced the cap and rotor. That fixed the miss when cold problem, but then it ran like crap over 3000 RPM. It was being starved of fuel, so I replaced the fuel filter, and everything was great. It had more power than before.

I figured the weaker spark from the bad cap and rotor was preventing it from producing enough power to demand more fuel than the filter could flow. Replacing the cap and rotor gave it a hotter spark, so it was now able to demand more power than the old filter could flow, resulting in fuel starvation.

At least that's what I've convinced myself.
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78 924 NA
5-lug