Boost problems

[supermario300hp]

ok so after my recent 20g upgrade, im having a problem with boost. i have it set at 16psi for right now until i have time to tune it properly. meanwhile, while driving at full throttle yesterday in 5th gear the turbo would spool hit 16psi, hold until 5k rpm, than slowly creep up all the way to 30psi! im sure i have my boost controller hooked up correctly. its a hallman bottom nipple to source in compressor housing, side nipple to wastegate. what could be causing this?!

Come on nobody has any ideas?!!!!i need help here!

 

[95dsm4g63]

a bad wastegate on the turbo perhaps?

 

[MemphisGSX]

are you runnin the stock wastegate or do you have an external?

 

[supermario300hp]

possibly, i just dont think so because its basicall brand new.....is there anything else that would cause these symptoms.

 

[GRAVEDIGGER]

Just answer the question... Are you using an internal wastegate with an actuator rod on the turbo, or do you have an external wastegate on the manifold or o2 housing? I am willing to bet that you have an internal wastegate on the turbo and because you are running such low boost pressure it is unable to bypass enough of the exhaust gasses and is causing a spike up in the high rpm's.

 

[supermario300hp]

are you runnin the stock wastegate or do you have an external?

stock wastegate

so your saying id be better off running the boost up over 20? and that could potentially solve my problem?

 

[cliffkemp]

If you car is not properly tuned, how can you 'slowly' creep to 30 psi and not have any issues or sputtering....30 psi is a good bit off of a 20g and is about the time you would be blowing hot air. If using the stock WG, that would basically answer your own question. There is a big difference between 16psi and 30psi.!!!

 

[GRAVEDIGGER]

Either tune it properly for higher boost and go from there, or quit driving it WOT, especially in 5th gear.

 

[supermario300hp]

If you car is not properly tuned, how can you 'slowly' creep to 30 psi and not have any issues or sputtering....30 psi is a good bit off of a 20g and is about the time you would be blowing hot air. If using the stock WG, that would basically answer your own question. There is a big difference between 16psi and 30psi.!!!

Well since i cant get the car tuned until at least next week, i figured id set the boost low and just cruise around until i can. I dont know why im not having any sputtering, but it slowly creeps up to 30 and i obviously let off the throttle.What do you suggest i do? go external?

Either tune it properly for higher boost and go from there, or quit driving it WOT, especially in 5th gear.

That would be an easier soulution. but do you think i should stay internally gated? and get it tuned. or swap now before i go?

 

[cliffkemp]

Well since i cant get the car tuned until at least next week, i figured id set the boost low and just cruise around until i can. I dont know why im not having any sputtering, but it slowly creeps up to 30 and i obviously let off the throttle.What do you suggest i do? go external?



That would be an easier soulution. but do you think i should stay internally gated? and get it tuned. or swap now before i go?

Externally gated turbos can usually take more boost before creep depending on the size of the hole. I have no creep on my laser with a 38mm WG that is external. My talon has no creep with the stock wg for the 16g on it either. It sounds like your set up is not working as it should and now is the time to decide if you want to go external or not. You can port the internal gate but, it will do just so much. If you plan on running a larger turbo or high boost, do it all now and go external and solve the future problems with creep.

By the way, I have not had any creep with an SC61 or a Green on my laser with the 38mm WG.

 

[GRAVEDIGGER]

I would just stay with what you've got now and see what happens. If you go to an external gate you will have to adapt your exhaust manifold to mount one on there and the flapper door will have to be welded shut, or you will have to get a different o2 housing able to accept an external gate, but that way you will have to remove the flapper door and leave it open. So you see it's not super quick and easy to add an external wastegate.

 

[cliffkemp]

I would just stay with what you've got now and see what happens. If you go to an external gate you will have to adapt your exhaust manifold to mount one on there and the flapper door will have to be welded shut, or you will have to get a different o2 housing able to accept an external gate, but that way you will have to remove the flapper door and leave it open. So you see it's not super quick and easy to add an external wastegate.

True...I just got a gasket that does not have a hole on the WG side and, there you go, dont have to weld anything shut. I also, got a mani with the external provision already done. All he will have to do is get an EWG/piping to divert the gases. As you said, it will not be that cheap but, no more creep.

Depending on how he wants to do it, it would be cheaper to just get a manifold that has an EWG provision as mine did. If he has stock fans, that will be another issue as well.

 

[supermario300hp]

i know its not easy thats why i didnt do it in the first place not to mention the cost of nice wastegate.thanks for your help. guess ill just limp it around until i can get it tuned.

Externally gated turbos can usually take more boost before creep depending on the size of the hole. I have no creep on my laser with a 38mm WG that is external. My talon has no creep with the stock wg for the 16g on it either. It sounds like your set up is not working as it should and now is the time to decide if you want to go external or not. You can port the internal gate but, it will do just so much. If you plan on running a larger turbo or high boost, do it all now and go external and solve the future problems with creep.

By the way, I have not had any creep with an SC61 or a Green on my laser with the 38mm WG.

See i tried to make provisions to eliminate boost creep. im running an open dump o2 housing and its still doing it. id really like to keep my car internally gated. as money flow is limited right now.