Hey guys quick question. I just put together manifold with 6466 single scroll turbo and 38mm wasegate recirculated back to the downpipe. I have a crazy boost creep, yes I know wasegate is too small and location of the wasegate etc. Is it better to add another 38mm on another side or just re-do the piping for bigger size and install 1x 44mm wasegate? Which option will give better results. It will never be on low boost but to start tuning I have to start with around 25-30psi and right now boost controller is set to 25psi and creeping right away to the moon so I had to abort the tuning. Thanks!!!!

 

A single 44 will creep about 7-10psi over spring.

Dual 38's will creep about 3-5psi over spring. Recirculating on a big turbo isn't helping you either. Need to vent the gates man.

 

Yea I know recirculating is not helping. I absolutely hate vent gates. So better option would be 2x 38's I think. It will be run at 40+ psi but to get there I have to control the boost somehow. My first thought was to do single 44mm but I am not sure at what boost level it will stop creeping. If I install 22psi spring on 44mm gate will it still creep over that spring another 7-10psi? Thanks

 

I would say if your driving it on the street the 38s will be fine. And I agree with Sean vent them babys as well. I know on my car with the power it makes my twin 38s only creep like 2 psi at most but I am divided t4. If it were me I would set the 38s up with 26 lbs springs and call it a day. That is what I will be running with my hpt 6466 that is currently on my car. I think more spring pressure will help but so will venting unfortunately.

 

Thanks a lot for your help. I will most likely weld in another 38mm. I will recirculate this one into the downpipe also, for me the sound of vented gate is like old Camry with leaking exhaust I absolutely hate it. I know vented to atmosphere has better flow and I know recirculating is taking some of the hp but I just have to recirculate it. There is a lot less work to just install 44mm but I am worried that it will be not enough. Current single is hitting 25psi at 5200rpm and is at 35psi at 7800rpm that's where I abort the tune because at 9500rpm I would be at 45 or more hehe.

 

Instead of doing all that extra work why not just add stiffer springs to your existing wastegate? I mean unless your twin scroll there is no need to add another wastegate. and if your creeping that much then its definately a stiffer spring issue. What spring is in the wastegate now? And unless your running extremely large cams and super stiff springs why are you trying to rev out to 9500? Most cars wont make any power past 8000 in 80% of the time.

 

I did installed the stiffest springs you can buy to this wasegate which is 1.6 bar I believe 22 or 23 psi. About rev it that high I do have gsc s3 cams and gsc conical springs shimmed to 120lbs intake seat and 125lbs exhaust install height seat pressure. It will be shifted at around 8800-9300 area. Rev limiter is set to 9700rpm. If I can only have at least 30psi boost steady with not a lot creep at my starting point it would be perfect but look like it wont happen on this wasegate. It will never be run on less than 30psi boost that's why I welded in single 38mm in the first place but look like I was wrong.

 

Ok let's start over which wastegates do you have? I run tiall mvs with 26 lbs of spring pressure and I held 62 lbs of boost no problem with no creep with my s372. I run wastegate pressure as my low and 62 lbs of boost on e85. My next question would be which turbo and in what configuration is it in that way I have the total picture. As far as the springs go idk if 120 and 125 lbs of seat pressure will hold . I know kiggly race only springs are for high boost applications and to rev way out and I know those are in the 130 plus range.

 

Ok lets start from the beginning. Turbo is precision single scroll 6466 new gen,(1000hp turbo) manifold t3 and single tial F38 wasegate with highest springs 1.6 bar so around 23-24psi. Those gsc conical valve springs are good for 50+psi boost and 10,500rpm's from factory with 115lbs intake and 120exhaust with no shimming. Mine are shimmed and are 120/125 so valve springs are good for 55psi boost and 10,500+ rpms, so nothing to look there. The issue is even on spring pressure it does hit around 25psi boost at 5200rpm and I have 35psi boost at 7800rpm ( I did boost cut for 35psi for a reason for now) so it does have crazy boost creep, wasegate is too small. Now I am considering to cut out pipes for wasegate and weld in thicker pipes to accept tial mvr 44mm or just add another tial F38 on the other side of the manifold. Faster would be to cut out and install single mvr 44mm but not sure if its going to be enough to control the boost at 30psi range for the start. The location of the wasegate is not the best because it is in manifold ofcourse but at around 90 degree angle like most of the manifolds for evo but all of them are with 44mm wasegate running such a big turbo.

 

Different turbos creep different amount. Precisions definitely creep the most. Where a Garret will only creep 2-4psi, a precision will creep 6-8.

 

Ok thanks for all the info. That helps alot honestly.next question is going to be what is the lowest psi you plan to run on that turbo? That is where that 44mm wg will hurt you. It is made for high boost applications and if you run say 30 psi I am sure it would do that but nothing below that to start.I am starting to think its not so much wastegate as it is possibly the turbo like Sean said. I don't have really any experience with the Percision stuff but I will take his word on it lol. It is really hard to say at this point what s going on. I am not sold on the wg being the issue though.

 

True, I have noticed that before also on Garret turbos, Would adding another 38mm wasegate or changing current one to 44mm and thicker pipes be a better idea or that's really don't matter? Thanks!

 

The lowest will be run at 30psi, and only so I can tune it, than will go higher boost to 40-45psi. Not sure if I should do another 38mm wasegate so twin 38's or just one 44mm. I have a feeling like it is pointless of doing 2x 38's if it is going to run on 40+ psi boost. This 1x 38mm is for sure too small as well as piping for this wasegate 1.50 OD . That's why I am leaning towards the single 44mm but I am more the engine builder that turbo set up guy that's why I am asking here.

 

2x 38's flow more than single 44. You should do to 2x 38's.

We do it on ETS kits all the time because it's what they come with. Depending on the turbo, 20-24psi of springs will get you 30-32psi of boost on wastegate pressure.

 

Thanks a lot for help!!!