Effects of camshaft timing on turbo spool-up

[Camden Lindsay]

<<the turbo may be shot-- but it doesn't leak/burn any oil or make strange 
noises...  I should mension, though, that the boost coming so late may have 
to do with load on the engine, as the motor is in a 4k with the 4.11 gears 
(rather than the 3.89 or whatever of the 5kt and ur)
--when i start in second instead of first, the boost does come on a bit 
quicker--

>
>When you say that you have retarded the cam I think that you mean that the
>valves opens a bit later in the stroke then they did before,

--correct that is what i meant by retarded....--

>but other
>things in your explaination lead me to think that you have advanced the
>cam(the valves open earlier in the stroke then before).

--I'm sorry that i don't remember which i did-- it was about a year ago, in 
the winter time outside.  The car's been sitting in a field, only to be 
started occasionally since then...

>The later will
>release hotter exhaust gas to the turbo and it will spool quicker and >at a 
>lower rpm.

<<allright

>
>But you should check your cam timing! I don't think that your car is
>performing very good if you have retarded the timing 16º from the stock
>setting. It will probably not work very well if it is 16ºadvanced either.

--I haven't really driven it much as it is.  perhaps 200 miles, not hard.  
Right now i dont' have an intercooler set up either, so everythings kindof 
wacked.  I take it pretty easy on it...


>models use the distributor for ignition
>timing. That will ,definately let turbo spool quicker, but it will >cost 
>you huge amounts of power and will most likely damage a thing or >two if 
>you give it the time.

<<it is the stock 4k ignition, albiet with a different vacuum advance setup 
(from a 89 saab 900T), and after i changed the cam i re-timed the motor---

>BTW, it is VERY important that you don't have a leaky
>exhaust manifold. Turbo Audis are extremely sensitive to this.

<<yeh, already had the cracked manifold welded-- hasn't had much mileage on 
it since then so should be good...

>Please let me know the model of the car.

<<so, here's the deal-- it's an 84 4ksq with an 8? turbo block (definitely 
KH, not sure which... think 83), a 87 MC head/cam/manifolds
and not sure which turbo... it does have the water cooled turbo though...
right now just running the stock 4k fuel system, soon to be Megasquirt!
so, really it isn't running "as it should"-- i just was interested in the 
why the advance/retard effected the spool-time....

Thanks for the reply,
Camden

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