Hello

I just moved to Santa Monica to start a new job with Audi (i design cars) this past week. All is great except the 'Fix Daily.'

So I'm on these mountain roads on a hot day (~85-95 F) and on the uphill sections after 15 min of hard driving, the boost starts to drop slowly until there is no boost at all. After the car cools a bit, then the problem goes away.

Mods;
boost, egt, water guages
ast
downpipe

 

Could you hear any air ? and if you were moving the whole time I wouldn't suspect heat soak (generally a byproduct of the car sitting still) I would expect a coupling letting go or a solenoid starting to fail.

 

check valves? I replaced them with viton ones from Dale Clark, and no problems at all so far.

 

Those would be the first things that I would check.

 

Solenoids or Check Valves. Then, since I didn't see you list silicone vacuum lines, I would check to see if any of those rubber vacuum lines are cracked or split...even if they are not they could be so worn that they collapse and suck themselves together.

 

Hmm. My mechanic seems to think that the stock rubber hoses from the intake box to the turbo are getting too hot, softening, and collapsing under boost. (william from c2- been racing and working on FDs for 10 yrs) Could this be the problem? I think the vaccuum hoses are fine since i just replace the motor and they seemed fine at the time.. (though i should really replace them..)

Solenoids and check valves, huh? haven't checked them yet.

I didn't hear any air escaping nor were any couplings loose.

Oh, i forgot to put in my mods list the brand new 99+ stock twins. (but I wouldn't think that really would affect it) and koyo radiator.

thanks for all you help!