tial 38mm or 40mm? with GT-13....

[v8s_are_slow]

i bought leon reitman's GT-13 not long ago and almost to the point that i'm ready to throw it on (dang tranny problems....ugghhh!!!). anyway, i'm buying an external gate next week and was wanting a tial 40mm. i noticed that sbr took them off of their site so i e-mailed to ask if they were still selling them. they said they had 10 left (well, 8 now) and that a 38mm would do fine unless i wanted to try and snag one of the last few remaining 40mm's.

i'm gonna weld it to the manifold and dump to atmosphere. don't plan on running lower than 15 psi. does anyone see any problems with running a 38mm and creeping? that's my only concern. i'd like to get a 38mm if i save money but not if it's gonna creep on me and give me a headache in the long run.

incase ya'll need a brief listing of the mods i'll be running, here ya go:

sbr GT-13 turbo
dejontool race front mount
3 inch gm maf and translator
sard bov
full 3 inch atr exhaust with test pipe
255 pump
afpr
660 injectors
fidanza
act2600 pp
6 puck disc
4 inch intake pipe and filter
gauges and other supporting mods....blah blah blah.

thanks for any info or opinions.
scott

 

[GRNDSM]

Scott,

As you know, I ran a 40mm WG with this turbo and had no problems keeping the boost down. Of course, I never had a need to keep it under 18psi or so .

I have used Turbonetics DeltaGate, which is 35mm with OK results before, this was on 60-1 Garret. Depending on the rest of your set-up. You should be able to do get away with a 38mm TiAl, in ether case, you are not taking a big gamble.

BTW, a little back ground as to what is going on with TiAl. You know how last spring they went from 35mm to 38mm for their entry level WG? Well, the 40mm was supposed to be replaced with a 44mm model. But for one reason or another, they delayed the release of 44mm WGs. It appears that they are finally (a year later) converting to the 44mm WGs.

Frankly, I have been so happy with my 40mm, that I am not sure if they even need to convert it to 44mm. So I wouldn’t wait for the 44mm WG just to get a bigger valve. But that explains why there are so few 40mm TiAl WG’s on the market, right now.

Leon
RR

 

[v8s_are_slow]

thanks man, yeah i don't plan on ever running below 15 psi. i'd like to get the 38mm since it's so much cheaper and more money for me. but just wanted to make sure it's not gonna be a problem.

anyone think a manifold mounted gate would make a difference on creep issues? it's definately dumping to atmosphere. just wondering since i guess the exhaust in a sense would have to move back up and then outta the wastegate versus the O2 mount. and it's gonna be off one runner instead of getting it all. just trying to make sure. leon, not that i'd doubt ya at all, but just that we're setting it up differently since you had the O2 dump. thanks!

scott

 

[v8s_are_slow]

oh and just curious but does anyone know if the 38mm (or even the 40mm for that matter) comes with a flange to be able to weld it onto the manifold? or is that something i have to buy as well? do these things come with a bunch of difference springs so i can change em out to where i want it to open? or do i have to order it ahead of time? thanks!

 

[candela]

I think the dumped manny gate will be fine as far as having issues creeping with a 38mm. Yes it should come with a flange, but it does NOT come with a bunch of spring rates. You usually choose which setting you want and that is the only spring supplied... I have never inquired about purchasing another spring so I cant tell you how much they are. But if you know you aren't going to be running LESS than 15psi I would be getting a least a 1 bar spring so you can actually use it later on when you crank the boost up (anything less than that and it may be very hard to go past about 28psi or so)...

Good luck!

 

[Chrono]

hmm you know, even running only 15 lbs you could possibly go to a 35mm. However, if you do have future plans go with the 38 leave room for growth

 

[hostile]

Buy the 38mm and spend the money you save for an o2 housing gate instead of one from the manifold.

 

[v8s_are_slow]

so just to get this straight, are bigger wastegates for low boost applications and smaller one's for high boost? guess if you run high boost, you don't have to worry about venting off as much exhaust. this correct? the GT-13 is probably as big as i plan to run on my car and i already have the turbo. just checkin....

 

[hostile]

It really depends on the setup. Most people will be fine with a tial 38mm gate.

If you have a really big turbo and are pusing a lot of boost your motor is going to make more exhuast energy to spool the turbo.

You would need to bypass more exhuast to keep the boost down the higher the boost goes and the more airflow you have.

So that is why you see some of the higher HP guys using the bigger gates.