Why Am I not Building Boost

[supraguy31]

Ok all, Here is something that I cant figure out and Its making me think about selling....

Right now, I have a 57 Trim CT26, RC 550s, Lexus AFM, Megan Racing AFPR, MKIV Fuel Pump, SAFC, Wideband with a HKS FCD.

If Im out just doing my daily driving around and i boost in any gear, I can hold 17psi in any gear without a Problem. If I decide to go out to the track at any given time and Launch from the tree, 1st and 2nd will give me 15psi, 3rd about 11psi and 4th-5th wont let me get anything about 10psi reguardless of how hard im on the throttle.

With Stock everything, I was running High 14s, At this point with all the Upgrades, I still cant get out of the 14s... Best time as of not is a 14.093. Im about to just give up on this car unless someone can give me a Idea on what the hell is going on here. HKS EVCIV high boost is set for 1.2 bar. Cant even think about getting there on the track but no Problems during Normal driving.

Help or Im selling
Robert

 

[boost fiend]

what kind of exaust do you have? any fuel controlers? any mill work dont to the heads?

 

[robeats91t]

That's an odd issue, could be many things, first things that pop into my mind are boost leak, slipping clutch, or loose/faulty wastegate. Something on your car is not liking the harsh environment of the strip...

Just a quick thought...when you had your turbo rebuilt, did you check your wastegate actuator? They typically get weaker the older they get, and have trouble holding the wastegate closed, especially at higher-than-stock levels. This would affect your peak boost regardless of how you're controlling your boost levels.

If you want to test and see if it's the wastegate causing an issue, maybe slip a washer or two underneath each side of the wastegate where it mounts to the compressor housing to stretch out the diaphragm a little more. You may find that you get better peak boost on the top end.

It's something easy to check...if you do try this, be sure to double check the boost settings on your controller before you take the car out and romp on it--I know on cars without boost controllers, this "shimming" of the wastegate raises the peak boost level.

 

[supraguy31]

Well, I can say after going out today and resetting everything that its looking like a wastegate Issue.

I reset the Boost Controller and did the Inital setup. Odcourse, I only got 7 psi for low and High boost Setting. Now after setting up the Hight boost, I started as I would be at the Strip and what I noticed is that when the car starts to make alot of boost, Something seems to just let go. Im assuming that this is the Actuator door opening up and letting boost Pressure by. Its pulls hard, Boost starts pretty quick and all of a sudden you get that drop in pull feeling and the boost drops off.

Im shimming the wastegate to see if that help. Going to reset the Boost Controller again and reset inital boost, Go from there. Will let you all know what the outcome is.

Robert