Waste Gate Suggestions

[GTP091]

i'm in the process of gathering parts for a turbo system for my 91 dohc gtp. my next purchase will be the wastegate. what size would be good for this setup? 50mm 40mm 35mm?? i imagine that the larger diameter allows better response in the turbo system but is to large a backpressure problem with the drop that would happen when the waste gate opens?? I can't seem to find much discussion about this. any insight is appreciated>.

I will be using a T04E .85 turbine 60 trim in a twin scroll (maybe a B but not likely)- HKS blowoff valve - intercooler - catch can - and FMU.

thanks,

[timg]

A 38mm wastegate is probably enough (it's what I used), but if you can afford it, larger ones are a good idea. I've been pretty tempted by the new Borg Warner EFR turbos that have built in BOVs and wastegates. If you add in the cost of those components separately, they're actually a pretty good deal.

Tim

[GTP091]

That's kinda what I figured. I was going to go with some OBX stuff and found a few 40mm that look decent. thanks!

Completely off my own topic but are you happy with the t04e?? or wish you had gone with the 'B' ??? I'm still stuck on that one..

E spools faster? and I like that idea. B has a better powerband? also nice to balance out tourque

[RedZMonte]

I also have a 38mm gate on mine (Tial) and run the same T04e "60" as timg (bought them at the same time actually). I could not be happier with the turbo.... OK maybe a GT BB would make me happier.... ive got 60-70,000 miles on my turbo setup with no issues, no shaft play. Good turbo for a LQ1. with my OBDII setup, '96 Intakes im 331hp and ~355tq on 7psi, timg is in the same hp/tq range as i am with his setup.

S

[Mars]

I had a cheap ebay 44mm one for my first setup. Worked flawless with Greddy ProfecB boost controller. Now I have dual 38mm gates (also cheap ebay ones) that are working perfectly ! Have just been using the 6 psi spring with them though.

If you ebay one, I don't think you'd be too dissapointed.

They wanted 700+$ here for a 44mm Turbonetics, I got the ebay one for under 90$ I think...

Oh, come to think of it, I still have that 44mm gate, I can ship it to you for dirt dirt cheap.

[GTP091]

Do you have the springs, and flanges for it still? how dirty cheap?

[Joseph Upson]

Low boost = large gate, high boost = small gate, I have a 35mm wastegate with a 4.5 psi spring and still hit just over 8 psi with a boost signal directly from the turbo to the wastegate on the 3.9L. The only way I was able to limit it to just over 4psi was to take the spring out completely.

[Mars]

Pfft, 20$ + ship.

[dskopek]

If GTP091 passes on the gate i will take it for that.

[timg]

I like the T04E. I've bought a T67 DBB turbo to replace it, but it's still in an E cover because I wanted a smaller compressor cover. There's not enough room in the engine bay for much else.

Tim

[RedZMonte]

Low boost = large gate, high boost = small gate

Yes and no.... if you read Tial's site they say the same thing... but seems like everyone does it backwords (4cyl race motors run BIG gates and low boost street cars run small gates)... Tial recommends large gates on low boost apps so that you don't geet boost creep (cant divert enough gasses to keep boost at the spring level), hense the reason for needing a larger gate, allows more gasses to be diverted and regulate the boost properly. IF installed in the proper location a 38mm should suffice but if you have a 44mm gate it won't hurt anything.. you sould feed the gate to both front and rear banks so you can regulate the boost correctly... if you run it off just the front the rear can still spool the turbo and create boost creep/spiking and vice versa.

My T04E on my DOHC has a 38mm and i dont have any boost spike/creep issues. My turbo flange is not divided and my wastegate is run slightly more off the front bank, not ideal but works just fine.

[RedZMonte]

I like the T04E. I've bought a T67 DBB turbo to replace it
Tim

Your such a Baller.... Twin scroll?

[Driver_10]

I did pretty good with my JAZ 44mm on my s256 t3 turbocharged 3400 swap. (At least before I overreved the thing and the valvetrain let go)

I had no complaints otherwise.

[Joseph Upson]

Yes and no.... if you read Tial's site they say the same thing... but seems like everyone does it backwords (4cyl race motors run BIG gates and low boost street cars run small gates)... Tial recommends large gates on low boost apps so that you don't geet boost creep (cant divert enough gasses to keep boost at the spring level), hense the reason for needing a larger gate, allows more gasses to be diverted and regulate the boost properly. IF installed in the proper location a 38mm should suffice but if you have a 44mm gate it won't hurt anything.. you sould feed the gate to both front and rear banks so you can regulate the boost correctly... if you run it off just the front the rear can still spool the turbo and create boost creep/spiking and vice versa.

My T04E on my DOHC has a 38mm and i dont have any boost spike/creep issues. My turbo flange is not divided and my wastegate is run slightly more off the front bank, not ideal but works just fine.

Most probably do it backwards due to lack of knowledge, like me for instance. My wastegate is located properly about 1.5 inches from the undivided turbine inlet flange centrally exposed to exhaust gas from every cylinder. The rule is dynamic however, in that the size of the wastegate is relative to exhaust volume in general and boost level vs. displacement specifically. My 35 mm wastegate would be great for a 2.0 L running the same boost level that I'm running for example, but obviously through testing can't flow enough exhaust to allow its minimum spring rated boost pressure of 4.5 psi on my engine which is about 4.2L. So a 4 cyl race motor making 8 cyl power would certainly need an appropriately sized wastegate to avoid overboosting.

[Mars]

k no one has PM'd me about the gate, PM me if you want it...