more boost with each gear

[89mulletbird]

I logged several runs this weekend at a roll-on race event. My first run I had the boost set low and I got the following boost levels in each gear:

2nd 15psi
3rd 17psi
4th 19psi

I gave about 1 twist on my Hallman boost controller on each run, I ended up with this boost:

2nd 15
3rd 18
4th 25

It seems like my boost controller is only affecting 4th gear, and I"m not building up in the lower gears. What could be going on here?

 

[blackgn1]

What turbo is on the car? Looks like possible boost creep.

 

[89mulletbird]

What turbo is on the car? Looks like possible boost creep.

It's a 6152S with a THDP.

 

[TurboBuRick]

I would ditch the air regulator boost control and get a rjc.

 

[89mulletbird]

I was thinking about going to the SD2 chip anyways, which I could use to regulate the boost, or is RJC still better option?

 

[pacecarta]

i

 

[89mulletbird]

Are you meaning to remove the turbo housing and port the hole to 0.95" ? I never touched the turbo when I bought it so I'm not sure what size the hole is.

 

[pacecarta]

p

 

[89mulletbird]

So you think the boost may be creeping up in the higher gears? I still don't understand though why I'm only making 15PSI in 2nd gear no matter what I do with the boost controller.

 

[we4Mateo]

So you think the boost may be creeping up in the higher gears? I still don't understand though why I'm only making 15PSI in 2nd gear no matter what I do with the boost controller.

Higher gear = more load = more boost if the energy can't escape past the exhaust hole. It's a trick getting it to all work right. And if you get it to 15psi, you may have a hard time getting 25psi down the road when you want it and vice versa. You def can't leave it like it is.

 

[89mulletbird]

I'm not quite following what you are saying "if the energy can't escape past the exhaust hole".

I'm wondering if my puck isn't sealing properly? My spool seems quite laggy, I wonder if I have a small leak on the puck.

 

[89mulletbird]

I checked my puck, it looks well centered. The puck is 1 3/8" diameter and the wastegate hole is 1". I'm going to bypass the boost controller and connect my HD actuator directly to the turbo fitting and log the data in each gear. Also, I will sand the puck and turbo housing with some 400# to get the carbon off.

 

[we4Mateo]

Radius the inside turn of the wastegate hole in the exhaust housing. You may have a leak, but that has nothing to do with the high boost on the top gear. The boost can't be lowered because it can't let enough exhaust energy bypass the turbine, so it overboosts; I'm sure the puck is wide open in 3rd. The rest of the gears are different b/c the wastegate setup either isn't sealing, opening too soon, or can't relief enough energy at partial puck opening or a combo of all three. When you get it steady at 15psi in all gears, then everything is working correctly. To then run 25psi, you'll most likely need an HD gate to keep the puck shut as the porting you do to get to 15psi will make it that much harder to make 25+psi. Like most things with these cars, you have to choose.

 

[89mulletbird]

I did notice it was a sharp edge. I'm going to go drive my car right now without the controller and just see what it does with the actuator only. I really never want to run less than 19psi, I'm just trying to figure out first why I have a 10psi difference between 2nd gear and 4th gear.

 

[we4Mateo]

I did notice it was a sharp edge. I'm going to go drive my car right now without the controller and just see what it does with the actuator only. I really never want to run less than 19psi, I'm just trying to figure out first why I have a 10psi difference between 2nd gear and 4th gear.

Makes sense. If you leave the hole the same size and just radius the inner art of the hole, that should at least keep it stable within a certain range. May be 20+psi or 15-22psi, but that alone will help quite a little. Depending on results and wants, you can then make the hole bigger if need be.

 

[89mulletbird]

I just clean the puck, put everything back together and did a test run bypassing the boost controller, hooking the turbo outlet directly to the actuator. At WOT in 2nd and 3rd gear it was a pretty solid 12 psi maximum. Looks like I have a stock actuator? Should I buy an HD actuator? Also, I don't have the factory Y connector, I'm normally going straight from the turbo to the Hallman controller.

 

[we4Mateo]

I just clean the puck, put everything back together and did a test run bypassing the boost controller, hooking the turbo outlet directly to the actuator. At WOT in 2nd and 3rd gear it was a pretty solid 12 psi maximum. Looks like I have a stock actuator? Should I buy an HD actuator?

If you want more boost. You def need to port the WG hole if a standard WG produces 24psi. You'll need a HD WG to run above 18-20psi and control it up towards 30psi. HD gate is good if you plan to stay 18-30+psi.