rb92673
racecar
- Joined
- Jan 17, 2017
- Location
- San Clemente
I just got back from racing Lemons in Sonoma and have a problem I cannot figure out.
We raced Buttonwillow in September and car ran very well, it maxed out about 12-13 PSI with the stock actuator T3/T4 turbo. It would build to 10:1 AFR as it reached max boost. We did have problems with the turbo studs/nuts backing off on the 89+ manifold and eventually two busted. I had another 89+ manifold and had Yoshifab do the conversion service for T3. I did swap LH 2.2 distributors, but I did not change anything else on the car. It is running Microsquirt and I did not change the tune.
When we started at Sonoma Saturday morning, it was raining hard so we were short shifting. When it started drying up, one of my drivers said it was boosting to 20 psi and would not rev past about 4500 RPM. Sure enough when I got in it, it was boosting way faster than normal and going to full rich on the AFR gauge. I confirmed the boost readings from the MAP sensor.
Thinking wastegate flapper was stuck closed or actuator wasn't working, I wired the wastegate flapper open. I did not notice any change, it still was at 20 psi by 4500 RPM. I am going to take the wastegate off later this week to see if I notice anything.
Any suggestions on other things to look for?
B230FT in 745
T04E 50 trim
2.5" exhaust
no cat
single muffler
DEKA 80# injectors
Walbro HP pump in tank
pretty much everything else stock except for microsquirt using LH2.2 dizzy
We raced Buttonwillow in September and car ran very well, it maxed out about 12-13 PSI with the stock actuator T3/T4 turbo. It would build to 10:1 AFR as it reached max boost. We did have problems with the turbo studs/nuts backing off on the 89+ manifold and eventually two busted. I had another 89+ manifold and had Yoshifab do the conversion service for T3. I did swap LH 2.2 distributors, but I did not change anything else on the car. It is running Microsquirt and I did not change the tune.
When we started at Sonoma Saturday morning, it was raining hard so we were short shifting. When it started drying up, one of my drivers said it was boosting to 20 psi and would not rev past about 4500 RPM. Sure enough when I got in it, it was boosting way faster than normal and going to full rich on the AFR gauge. I confirmed the boost readings from the MAP sensor.
Thinking wastegate flapper was stuck closed or actuator wasn't working, I wired the wastegate flapper open. I did not notice any change, it still was at 20 psi by 4500 RPM. I am going to take the wastegate off later this week to see if I notice anything.
Any suggestions on other things to look for?
B230FT in 745
T04E 50 trim
2.5" exhaust
no cat
single muffler
DEKA 80# injectors
Walbro HP pump in tank
pretty much everything else stock except for microsquirt using LH2.2 dizzy