sillbeer

I received my car today. It's an 86 951. The car was recently repainted silver and it looks very nice but the engine bay is gold. Is that normal or was the car repainted a different color than stock? Anyways overall i'm pretty happy with it. It's very clean inside and out. Seems to run well at partial throttle however full throttle is a different story. I only ran full throttle in 1st and 2nd gear then let off. Anything over 5,000rpms it starts to cut out. It still accelerates just not like it should and it's very apparent that it's cutting out. The car has 2 power adders. Porsche cup chips and a manual boost controller set to 1bar. Any ideas? TIA.


-Destin

lart951

Welcome to rennlist, if the engine bay is a different color than the car it has been repainted with the wrong color. In regards to the cut off at high rpm's it sounds like the overboost protection. Does the car back fire when the hesitation occurs? does it happen at certain rpm range regardless of speed? how do you monitor your air/fuel ratio? also do you have another boost gauge besides the stock one?

Luis

RT930turbo

The gold engine bay suggests that the car has been repainted, I would pull up the rear mat and see what color the trunk floor is, most likely it will be gold.

As for the cutting out, I would check your cap, rotor, plugs and wires, in my experience these cars can be quite sensitive to worn ignition parts. It doesn't sound like you are hitting overboost protection ( if cup chips even have that feature???) that is a much more violent shut down.

The boost with a stock turbo should continue to fall off as the revs increase, the capacity of the #6 hotside just can't maintain a full 1 bar at redline.

RT930turbo

Luis beat me too it! Congrats on the new purchase by the way

sillbeer

It's not boost cut. When i've hit boost cut in other cars it's very apparent. Like hitting a brick wall. Also no back firring. I don't have a boost gauge for this car yet but plan on buying one soon. Also no way to keep track of the A/F as of now. I'll look into the ignition stuff.

-Destin

hally

Could be knock detection, & timing retard. How much boost are you running (need an aftermarket gauge) and how is your a/f? What fuel pressure do you run with cup chips, to run 1 bar boost safely on stock injectors you need a 3 bar fpr setup with matching chips.

gregeast

I'll second Artie's recommendation for replacing the cap and rotor. Might also be a vacuum/boost leak, which can also cause a hesitation, although in my experience that usually occurs more at the transition onto boost rather than the 5k rpms you're seeing. The boost/vacuum gauge will help you diagnose that one.

ttwitc9516

"if the engine bay is a different color than the car it has been repainted with the wrong color" Maybe it was like mine and was the wrong color in the first place, and now the engine compartment is the only place with the wrong color.

sillbeer

Yea. I like the new color alot more than the original gold. One more thing. I also noticed a vaccum line not hooked up. I think it's a vaccum line. It's just behind the air box. I'll take a picture of it when I get home.

-Destin

sillbeer

I don't think this is a vaccum line. Not sure what it is. Any ideas?

-Destin

hally

its your cycling valve - its been bypassed, no longer in use. A stock setup would have that red hose connected to that open metal cycling valve signal line. The other end of the cycling valve then is connected to the wastegate. So in the stock setup, the cycling valve controls boost. In your setup either a boost controller on that red hose, or purely your wastegate spring is managing boost.
hth

sillbeer

Thanks.

-Destin

black944 turbo

That cloth line also should be blocked that is going to the other metal line. That is another line running to the cycling valve. I don't know whether that would cause a vacume leak or not, but I would bypass it.

daniel951

i say rip all the venturi lines and cycling valve since u are running a MBC plus it helps clean up under the intake manfiold

dime1622

I second Daniel's opinion. It's cheap and easy and a good way to start getting intimate with your car. Because you will have to at some point