Sick of boost creep - what to do?

[bison]

UPDATE! THINK I have things under control now. Put a 7 lb spring in the wastegate and actually can now turn the boost down. Slowly turning it back up. Can only bring the car over 100mph in so many places around here.

No real lag issues either though I am sure the car will benefit from a converter change. 12" 2800 stall right now.

Good news. Now you may get drop off up top if you try to run around 30psi. Dont think you will be going that high though

 

[Bent6]

My experience has been that the external gates off the turbine housing just don't work very well with the new billet wheels. The problem isn't the gate or the hole size as much as the location of the exit. The exhaust gas is still partially entering the housing before it gets to the hole.

I went throught the same thing as you using the lighter spring - it would control when just rolling into the throttle but would overrun the gate when nailing it from a standstill. The lighter spring can also slow spoolup. Rule of thumb is to always run the heaviest spring you can for the best spoolup.

I'm sure you don't want to go this route but my solution was running the gate off the header and plumbing it back into the DP. Matter of fact, I used one of YOUR 3.5" dps with no wastegate provision along with some slicing, dicing, and welding with a 40mm gate. I can now control it as low as I want. PITA to fab but is the best setup for boost control going forward.

 

[protracracing]

How did you port the inside of the turbine housing around the wastegate hole?You have to port a wall at the top of the hole to help it turn.
I draw a pic of what I am talking about.I will try and post it.

Hope this helps
Dennis

 

[Otto J]

My experience has been that the external gates off the turbine housing just don't work very well with the new billet wheels. The problem isn't the gate or the hole size as much as the location of the exit. The exhaust gas is still partially entering the housing before it gets to the hole.

I went throught the same thing as you using the lighter spring - it would control when just rolling into the throttle but would overrun the gate when nailing it from a standstill. The lighter spring can also slow spoolup. Rule of thumb is to always run the heaviest spring you can for the best spoolup.

I'm sure you don't want to go this route but my solution was running the gate off the header and plumbing it back into the DP. Matter of fact, I used one of YOUR 3.5" dps with no wastegate provision along with some slicing, dicing, and welding with a 40mm gate. I can now control it as low as I want. PITA to fab but is the best setup for boost control going forward.

Nice job Wil,this is by far the BEST way to install an external gate

 

[ta88gta]

Thought id add to this post after finally getting my new setup running.

Im running a pte6265DBB turbo with a 3inch BGC downpipe(two piece/internal gate). I ported the housing hole to alittle over 1.25 of an inch but radiused the crap of it on the inside the whole way around the hole. And im able to get boost down to 13psi with a non hd actuator. Ill never run it that low but i guess it can be done. Only creep at that level was about 3/4 of a pound and at 20psi where it sits now creep is non existing, its ramps to 20 and sits there rock steady using an old nxs style boost controller.

 

[bison]

Thought id add to this post after finally getting my new setup running.

Im running a pte6265DBB turbo with a 3inch BGC downpipe(two piece/internal gate). I ported the housing hole to alittle over 1.25 of an inch but radiused the crap of it on the inside the whole way around the hole. And im able to get boost down to 13psi with a non hd actuator. Ill never run it that low but i guess it can be done. Only creep at that level was about 3/4 of a pound and at 20psi where it sits now creep is non existing, its ramps to 20 and sits there rock steady using an old nxs style boost controller.

The critical component is the non HD actuator. You could have gone smaller on the hole and still not had problems. You need a lighter spring to be able to adjust boost lower. You will run out of room if you try to turn it up much over if you crank it later. Back pressure will start to push it open on an application with cam and heads over 5500 rpm and you will get boost loss at rpm

 

[ta88gta]

i agree with you on that. But i also think that the way people are porting the wg hole has a large effect on boost controll aswell. I went with the non hd actuator because i knew there more than a few people having issues controlling the boost with the billet wheel turbo. As someone stated earlier JayC ran one with the gate rod disconnected and still ran up over 20psi. So in his sitution the spring pressure was irrelevent and getting the exhaust moving through the wg hole was the issue.

 

[cchilly]

ta88gta-

Glad to hear this. I'm looking at getting the 6265 and was worried I would have to get rid of my new internal gated downpipe.

Do you plan to bring it to the track with the new turbo?

Thanks for the info.

 

[ta88gta]

i do plan on getting the car to the track but not this year. The track up here closed for the season as of last friday, so i wont have any times untill next season.

 

[bison]

i agree with you on that. But i also think that the way people are porting the wg hole has a large effect on boost controll aswell. I went with the non hd actuator because i knew there more than a few people having issues controlling the boost with the billet wheel turbo. As someone stated earlier JayC ran one with the gate rod disconnected and still ran up over 20psi. So in his sitution the spring pressure was irrelevent and getting the exhaust moving through the wg hole was the issue.

I run a .110 hole that is radiused as you described and i have solid control with an HD actuator up to about 750 hp. Beyond that i lose boost over 5800rpm because of backpressure. Ive also used the same actuator on 2 other cars which were GTQ's/S's and had the same results. I never tried to run below 17psi though. If your running a 6262 or larger you arent gaining anything over even a TE44 on a 231ci unless you are well over 6k rpm at 17psi. GTQ's are useless under 600hp too. Just require more stall that will eat up performance and drivability.

 

[John Wilde]

I run a .110 hole that is radiused as you described and i have solid control with an HD actuator up to about 750 hp. Beyond that i lose boost over 5800rpm because of backpressure. Ive also used the same actuator on 2 other cars which were GTQ's/S's and had the same results. I never tried to run below 17psi though. If your running a 6262 or larger you arent gaining anything over even a TE44 on a 231ci unless you are well over 6k rpm at 17psi. GTQ's are useless under 600hp too. Just require more stall that will eat up performance and drivability.

I really hope you are wrong, I have a 6265BB a stock cam coming up...

 

[ta88gta]

Ill have to wait till next season to see how the standard actuator treats me when i try to go over 20lbs but i think ill be ok. all of my boost so far has been achieved by turning in the actuator rod. i havent even started playing with the controller and if it doesnt get to where i want it ill just swap in my spare hd actuator. i dont plan on goin over 24 25lbs on my stock bottom end.

 

[bison]

I really hope you are wrong, I have a 6265BB a stock cam coming up...

You will need to really crank it to see any gain John. Last year a friends car only picked up marginally with the 6262 and unopened engine compared to a 3255 and the 6262 runs were at a sea level track. Boost was high 20's. Id go with as much valve spring as you can stand and shoot for 30psi.

 

[marleyskater420]

I run a .110 hole that is radiused as you described and i have solid control with an HD actuator up to about 750 hp. Beyond that i lose boost over 5800rpm because of backpressure. Ive also used the same actuator on 2 other cars which were GTQ's/S's and had the same results. I never tried to run below 17psi though. If your running a 6262 or larger you arent gaining anything over even a TE44 on a 231ci unless you are well over 6k rpm at 17psi. GTQ's are useless under 600hp too. Just require more stall that will eat up performance and drivability.

well that stops any want I have of getting a 6265. Thank you for saving me $1,500.

 

[John Wilde]

You will need to really crank it to see any gain John. Last year a friends car only picked up marginally with the 6262 and unopened engine compared to a 3255 and the 6262 runs were at a sea level track. Boost was high 20's. Id go with as much valve spring as you can stand and shoot for 30psi.

Brian,

I am going from a stock turbo to the 6265BB, so I am sure I will see an improvement. Like you said it may not be any faster than if the car had a 44 around town. With the DBB Center Section I really don't need any more converter than a 44, so for me is no downside with drive-ability IMO. On a standard center section I see your point. However after spending money upgrading things in the past multiple times I bought this turbo to have room to grow for heads and a cam later. The same school of thought brought me to buying the 60lbs injectors when I needed to replace the stockers.
I really don't need them, but it is the max I will want to use on a daily driver with the stock computer.

If you want to shoot me a PM with more details I would appreciate hearing your first hand experience.

 

[leophious]

FYI There are fast stg II cars that use 4 Racegates.

 

[JayC]

We've reached the limit of what can be passed through the stock turbine housing wastegate hole.

External gates off the header are the way to go.

P.S. We build downpipes that incorporate them. Just send in your passenger side header

 

[bison]

Brian,

I am going from a stock turbo to the 6265BB, so I am sure I will see an improvement. Like you said it may not be any faster than if the car had a 44 around town. With the DBB Center Section I really don't need any more converter than a 44, so for me is no downside with drive-ability IMO. On a standard center section I see your point. However after spending money upgrading things in the past multiple times I bought this turbo to have room to grow for heads and a cam later. The same school of thought brought me to buying the 60lbs injectors when I needed to replace the stockers.
I really don't need them, but it is the max I will want to use on a daily driver with the stock computer.

If you want to shoot me a PM with more details I would appreciate hearing your first hand experience.

The 6265 should be ok with a 2800 zero boost/vacuum converter. How well the converter will work up top will depend on how hard you run it. If it were me id order a $595 old school Precision journal turbo with a .85 ex. and get a 9.5" converter from PTC and crank the boost upwards of 30psi and hold on. Should be low 11's with foot brake launches and blast to drive on the street. You would be in it for $1500 and be getting a converter that could be easily adjusted if needed later. Thats if your goal is to really haul ass with $1500 cash out lay. You will still have to run the 6265 hard to get some big gains. I probably am this way because i never had the $ when i was young to grow into parts. I was always the other way around running the hell out what i had because i couldnt afford to buy a bunch of matching components and i still found that i was faster than 90% or more of those guys when we raced each other even though they had $1000's more invested. I always tuned high boost with zero detonation. I might do a comparison on my blue car really soon. I have an old school AC converter in it with a 72 p-trim BB. Im thinking i can get the performance i have with it now by using an old TE 44 journal and a 9.5" PTC. The spoolup would be insane and the coupling efficiency would be at least 8% better with the PTC converter. Th dual nozzle alky will cover the smaller compressor wheel loss. Im thinking high 10 sec power at 26psi. Coupled with a tall tire it should be a real animal on the street. That is a total 93 pump gas application.

 

[2QUICK2B6]

The 6768 billet turbo i have on the GN is holding 13 psi fine with a THDP an HD actuator ? Its a bone stock engine with better springs. Going to be installing a CAM and GN1's later

 

[JP112_89]

I really hope you are wrong, I have a 6265BB a stock cam coming up...

IMO the 6265BB would be a better choice than an older 44. The 6265BB has the ball bearing option so IMO it's a better turbo. Plus, the turbo should be more efficient than a 44 at high boost. I have no facts to back my post however.

Just run a tight converter John. 26-2800