ohshixgoat

iTrader: (14)

Hey whats up guys just bought a turbo kit and it came with a 38mm ultra gate (turbo smart) waste gate. My turbo is a Precision 80mm gts, I think that I might have to upgrade to a 48mm or 50mm waste gate. Im open for anyone's expertise in this area. Its going to be pushed extremely hard with a forged bottom end 346 ls1. It came with 3 springs
andie

Bird-Of-Prey

iTrader: (23)

Hello neighbor. I think the 38mm is gonna be a little small regardless of how much boost you are gonna run. If you plan on "pushed extremely hard" you will definately need to upgrade to either the 48mm or 50mm Progate. The 50mm Powergate is an option as you can never have too big of a wategate. There is one for sale in the classifieds right now for a reasonable price.

goodol'93z

iTrader: (14)

I used a turbosmart 38mm wastegate, I have not finished my build but only time will tell. I too will be using a precision pt80 on a 347

Cmarsh

pushed hard? Does that mean high boost? If so, you should be fine. You need a larger wastegate when you are trying to run lower boost levels...for higher boost pressure, you don't need as much wastegate

Grr

iTrader: (2)

38mm should be fine with that turbo over 10-12psi

Bird-Of-Prey

iTrader: (23)

It's true that the more boost you are running the less gate you will need. If running low boost a larger gate is needed. Higher boost levels require a larger gate to bleed of excess pressure. Regardless of engine size or turbo size, if your going all out, get a high performance reputable gate and don't look back.

* When talking about something that could be the difference in blowing you motor, loss of power and/or causing a safty factor what does a $100 difference mean to you?

kbracing96

iTrader: (25)

Ya, a big turbo (especially on the exhaust side) and high boost, doesn't need a big WG. I'm running a 38mm Tial on a 346 with a small P-trim .96 A/R and having no trouble holding it down to 6-7 PSi to 6200

kbracing96

iTrader: (25)

That doesn't make since The reason you have high back pressure is cus your forcing ALL the exhaust thought the turbine to get the high boost. Very little if any exhause is going though the WG... The WG flows the most ONLY during low boost and high RPM.

Bird-Of-Prey

iTrader: (23)

Kbracing, are you sure? "The WG flows the most ONLY during low boost and high RPM"
I beleive you can't have too big of a WG. Big won't hurt ya here. If your WG is to little or cheap (Ebay) you might have boost creep problems. Or it may hang open causing all kinds of driveability problems (bin there, know that). Also if he is truly going to push extreme to the max, why wouldn't you want the best possible parts available?

Grr

iTrader: (2)

actually he is correct, using a smaller gate on high boost applications is just fine. The smaller valve reacts much quicker and will give a more consistant boost reading. You need a bigger gate to attain a lower boost, but a 38mm will be just fine over 10psi. I ran a 60mm gate and if i took the spring out i would only make .5-1psi.

jfg455

iTrader: (5)

But on the other end if your wastegate is to small then it will not be able to exhaust enough pressure and you will see boost creep. Turbo buick guys see this all the time unless they open up the wastegate area.

TiAL

i'd go with a 60mm so you can control low boost launching and high boost down track

if you don't ever need to control low boost, go with a 44mm

TiAL

take the gate off, i bet you make the exact same boost with no wastegate at all

kbracing96

iTrader: (25)

Remember, we had this discussion before and I posted pics and screen shots of logs to prove my setup and that was with a MasterPower T70 turbo (.68 turbine A/R) and 38mm waste gate on this same motor. And now I have a bigger turbo. I have no need to run less then 6 psi of boost

ohshixgoat

iTrader: (14)

so are you going to stay with the same 38mm gate..

and your planning on running 10+ psi?

That is what I am planning on doing. I m plan on having a nice boost controller were I can program 8-9 psi in 1st gear then like 12-13 in 2nd then Im hoping for 18-20+ in 3-4-5-maybe 6 gears.
I just dont want the gate to blow up on me...lol

kbracing96

iTrader: (25)

I plan to keep the 38mm gate unless for some reason, I start getting boost creep. I have ran as much as 15psi on the T70 turbo. Waiting for spring to get here before beating on the T76 to much.

For what you want to do, I see no reason why a 38mm gate wouldn't do what you want. The bigger turbo you run and the more load and boost you run, the less WG you need cuz your wanting to force more exhaust THOUGH the turbo, and not dumping it. That my thinking any way...

ohshixgoat

iTrader: (14)

yea I think so too, If I can sell it and get a bigger one I will, Intill then Im just going to keep it on there.

ohshixgoat

iTrader: (14)

sent you a pm

TiAL

was backpressure in those logs?

Louis

iTrader: (7)

Surely you understand the concept of a wastegate and how its surrounding settings have a very large impact on how it performs.

I could run around the internet and tell people that a 38mm gate would work on my PT88.....

but would those people who saw, and copied my setup, realize that I had a STOCK catback muffler? And that when I failed to mention that when I opened the 3" cutout in the mid pipe I picked up 4 psi, and that when I opened the 4" cutout on the down pipe itself, I picked up another 4 psi? Gee, now all of a sudden Im running 12 psi..... where did all of that boost come from? I didnt change turbos!!??

I run the BIGGEST gate I can physically fit. The days of blowing open gates really are not an issue with todays boost controllers and gate designs, but its up to YOU to figure out what YOU need. Sure, If your setup is poorly matched, you might have a severe back pressure issue, but that is where it goes beyond just bolting on parts.

I like to control boost So I run a big gate. If you need more boost, add a bigger spring Its much easier to swap springs, than swap gates.