TA-49 Boost Creep

[mgmshar]

I guess I'm just looking for an affirmation here...

My combo is stock engine, TA-49 with Garret housing, CAS-V2, THDP, and ATR 2.5" exhaust. When I put the ATR system on (replacing the stock exhaust system), I noticed that my boost went up a lot. With no other changes, I went from about 16psi to about 18-19psi.

I have since burned a chip that commands the wastegate at a very low level (like 30-10% duty cycle as rpm increases), and I've replaced my HD actuator with a stock one. I just went for a drive, and I noticed that the boost is creeping up with RPM. During a second gear pull, the boost started at about 14psi, and crept upward until it hit about 16psi at the shift into third. Similar situation in third gear, except the numbers were a bit lower.

Is it time to port my wastegate hole? Has anybody out there with a similar combo had to port their wastegate hole?

Thanks,

 

[mgmshar]

ttt

(what does "ttt" mean, anyway?)

 

[turbot2112]

ttt means to the top. as far as your boost creep problem, i would start by finding out if the puck in your downpipe is covering the entire wastegate hole.

 

[mgmshar]

Everything was great, until I installed the ATR system. I could run 17psi nice and stable. Now things are flowing so well that I think my wastegate can't handle it. My best guess, anyway.

I'll probably dykem the wastegate hole with the puck soon. I was hoping that somebody else with a TA-49 could tell me if they've had similar problems.

Later,

 

[Will Rhoades]

-I am having a similar problem with a Ta-49. What was your solution?

 

[mgmshar]

Very old post, but after I wrote the above, I ported the waste gate hole to be almost as big as the puck on my THDP. I also radiused the wastegate area inside the exhaust housing to improve waste gate flow. I did NOT radius the outlet of the hole where the puck contacts the hole. This solved the creep problem.

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[Will Rhoades]

Thanks for getting back to me. I know this is an old thread. I have an 3inch rjc dp. It has a very healthy puck on it. One problem I keep hearing with porting the exhaust hole is most people have to replace the actuator with a hd one, especially with high boost levels. Any problems sound familiar in your case?

 

[mgmshar]

Right now, I am running a regular duty actuator with a check ball style boost controller. I can get the boost down to less than 12 psi if I want. I'm currently running about 17 psi just fine.

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[Will Rhoades]

Thanks for the info!

 

[Joel A. Russo]

Right now, I am running a regular duty actuator with a check ball style boost controller. I can get the boost down to less than 12 psi if I want. I'm currently running about 17 psi just fine.

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What boost controller are you using?

 

[mgmshar]

Just a simple check back type that I think I found on the internet many years ago. I remember paying extra for a ceramic ball at the time, but I can't say whether it has really done any good. It does do a good job of spooling the turbo quickly and holding boost steady.

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[we4Mateo]

I ported my TE44 exhaust port and even with HD actuator, I can get it down to 14psi if I run it tuner style from turbo to actuator. I run a rjc boost controller too and it'll keep it anywhere from 17psi to 26psi rock steady. To get 30psi, I have to wire my wastegate shut.

 

[Dwilc47]

I ported my TE44 exhaust port and even with HD actuator, I can get it down to 14psi if I run it tuner style from turbo to actuator. I run a rjc boost controller too and it'll keep it anywhere from 17psi to 26psi rock steady. To get 30psi, I have to wire my wastegate shut.

I'm running the Same turbo and rjc boost controller. I'm trying to adjust the boost past 26 with the controller but the boost won't seem to go up with each quarter turn. Am I at my limit? I didn't think I would. If I get it on it steady from an on ramp it'll spike to 28 then settle to 26 but if I do a wide open pull and punch the gas at 55 the boost will hit 26 but not spike. I turned it down a full turn and it was still at 26 pounds. I pull the controller out to adjust it felt hard to turn and now when I got home after messing around I pull it out and it turns easier. Can't explain it at all Any ideas?

 

[we4Mateo]

I'm running the Same turbo and rjc boost controller. I'm trying to adjust the boost past 26 with the controller but the boost won't seem to go up with each quarter turn. Am I at my limit? I didn't think I would. If I get it on it steady from an on ramp it'll spike to 28 then settle to 26 but if I do a wide open pull and punch the gas at 55 the boost will hit 26 but not spike. I turned it down a full turn and it was still at 26 pounds. I pull the controller out to adjust it felt hard to turn and now when I got home after messing around I pull it out and it turns easier. Can't explain it at all Any ideas?

You're maxxed. If you want more boost, wire the wastegate shut and make sure your headers are in good shape as backpressure will be high!

 

[mgmshar]

FWIW, the compressor wheel on this turbo is pretty much maxed out around 26 to 27 psi. Yes, you can get the boost higher, but the compressor is so inefficient that the mass flow gain through the engine is minimal. You might be better off trying to run a little leaner or more spark timing advance if you're looking for more power.

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[Dwilc47]

You're maxxed. If you want more boost, wire the wastegate shut and make sure your headers are in good shape as backpressure will be high!

Thanks again for the advice. 26 isnt bad though. But I don't have a stock waste gate. I attached a picture. I actually have a manual boost controller, I believe a turbonetics. Looked on the web, looks like there are two types one for up too 25# and another up to 50#. I think I'm stopped by my manual boost controller.

 

[KEVINS]

26psi was the limit on mine also so in order to run more boost I had to run an extra spring alongside the actuator. The first spring I ran was good enough to hold more boost but b/c it was so close the exhaust housing it would get hot then soften and loose spring pressure until it cooled off. I just put on an even shorter and heavier one on and connected it to a bracket that is close to the exhaust housing and that appears to be working better.

ks

 

[we4Mateo]

FWIW, the compressor wheel on this turbo is pretty much maxed out around 26 to 27 psi. Yes, you can get the boost higher, but the compressor is so inefficient that the mass flow gain through the engine is minimal. You might be better off trying to run a little leaner or more spark timing advance if you're looking for more power.

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That's not true. It's the exhaust turbine that will hold you back with a TA49 or a TE44 or any of the other turbos that use that exhaust wheel. The compressor is hardly out of steam yet though. I pick up another 20+rwhp going from 25psi to 28 which holds to the roughly 10rwhp/psi on my combo. Unless you are trapping 122mph in a full weight car, there is more compressor to use there yet.