Background:

I autox my (completely stock, with a tune) Evo regularly and this past weekend, in the middle of the day, the car went way down on power. I quickly realized that the turbo wasn't spooling up properly and parked the car for the rest of the day. The car runs smoothly at idle, part, and full throttle, it just isn't making that much power. I drove the car 90 miles home with no issues. Further investigation has reveled that the car is making ~7psi of boost (I understand that is wastegate pressure?). I am guessing the BCS is toast, there is a problem with the wastegate, or some vacuum hose between the two is not sealed up properly. I haven't had much time to investigate the problem yet, and hopefully will have some time on Saturday to go through it.

Dilemma:

My next points event is on Sunday, on a relatively slow course where the extra power doesn't really do anything for me. Would I be stupid to run the car at this event? Given that the car is running smoothly and I don't believe there is a boost leak, all the air going thru the MAF is going into the engine and consequently the AFRs will be right, is there any (engine) safety issue I am not considering?

The points are not worth blowing up the motor for, however if there is no risk, I have a reasonable shot at a championship and I'd like to keep that dream alive. Unfortunately both my other cars are on all-seasons right now and would not be competitive.

Thank you for reading my novel, I appreciate any enlightenment you can bestow upon me.

-Bryan

 

Why not do a boost leak test on the car and check the car over. It is probably something stupid.

WG pressure is more like 11 psi

 

The simple answer to that is time.

I intend to do whatever it takes to figure out what is going on with the car, but I have about 3 hours free between now and Sunday morning, I will be going back under the car tomorrow afternoon, i am hoping to find a loose vacuum hose somewhere, but in all likelihood I would be racing it in its current condition on Sunday if I choose to race it.

 

I would do my best to find the leak before tracking it again. If you have large boost leak, then your turbo is basically running at terrible efficiency. It is pushing really hard (that's what she said) to achieve its 26psi target, but it never reaches it. So instead of slowly tapering it will keep boosting at a high rate of RPMs. This can lead to problems such as over spinning the turbine and with journal bearing turbos it can cause serious issues.

Don't be lazy. Find the leak and fix it.

 

Run it!

Engine can handle any AFR at 7psi


but
Just make sure the turbo isn't sending bearing material into oil first

 

I assure you it is not laziness preventing me from doing the leak check. I have almost no free time between now and autox on Sunday AM between work and other commitments.

I'll spend my free time on Saturday running a boost leak check rather than trying to determine if there is a bad connection between the BCS and the wastegate. If the system is tight I think I am going to chance running the car since I won't be getting above 45 in second gear (will only rev the engine high when shifting from first to second at the start).

Thanks for the input I have received so far. It is much appreciated.

-Bryan