SAMCRO08

Im in the process of putting together my setup for my built B18c1 and need alittle advice on proper wastegate selection. I have a mini ram manifold to where the wastegate flange is welded 90 degrees right above the turbo flange. The flange is a 38mm. I was looking at TIAL wastegates and want to run about 22 pounds and need something with proper flow. The car will back track driven only.
Would a 38mm be too small or should I go bigger? I'd like to put a stiffer spring in there to maybe run off just wastegate pressure or maybe use a boost controller if thats a better option. I did research on here but I read different things, like using a bigger wastegate for lower boost pressures. These kind of things I'm not to familiar with on why you would choose that.

Thanks!

ricetastic

if u plan on running 22 psi, then a 38mm should be fine, larger WG is needed for lower boost levels..but another factor needed, is what turbo are you running?

SAMCRO08

im running a t3t4 60 trim garrett

ricetastic

38mm should be fine..if u had a larger turbo and were running a bit lower boost u might see some spike issues...but i think u should be ok

TheShodan

iTrader: (14)

38mm should be fine. Running wastegate pressure actually means it will open up slightly early than the 22psi you're looking for (like 21.8psi or so). A manual boost controller would take care of the rest. No need for anything complicated. Though at 22psi, you're getting close to past its efficiency range on a T3/T04E 60 "trim".

Turbo-LS

iTrader: (4)

What brand mini ram are you running ? Do you know what exhaust wheel is on the turbo ? I have seen the mini rams creep quite a bit with rpm on smaller gates. I would imagine with a 60 trim you should be ok but if you experience creep you'll need to step up to a 44mm or larger

TheShodan

iTrader: (14)

Not at these pressures , Turbo-LS. "Creep" is much more than some exhaust manifold design. Over the last 7-9 years that each of these manifolds have been developed I've found that many of these same manifolds that work just fine without "spike" or "creep" issues, only to have someone with the wrong electronic boost control setting cause a low boost application to spike higher than its target boost.

90% of the time its because of the fact that they're trying to run too low of a target boost pressure in the name of "traction control" only to "creep" past his target boost pressure from the way the solenoid was operating, not from the design of the manifold whether its "teardrop" or not. Yes, a "teardrop" collector is optimal, but I don't get how those that weren't could control boost soo effectively with the right sized wastegate, then all of a sudden , 5 years down the road, same setup, but different boost control, the manifold is now responsible for boost creep. Makes no sense.

I'm sorry but at 22psi of boost pressure as his target, he's more than fine on a 38mm. Going 44mm would only bleed too much boost, and transient response would suffer. Stick a manual boost controller as part of the target, with a boost reference source that isn't too strong (like the intake manifold or vacuum block with the brake booster as a primary source) and you'll be fine.

Freemananana

iTrader: (3)

My understanding is that you should be just fine with the 38mm waste gate. When people use big turbos and a low amount of boost pressure, there is excess pressure in that system. That is when you need a larger wastegate. If you are running the turbo close to it's efficiency, you should be fine with a smaller wastegate since you won't be using the wastegate as much. TheShodan also brought up the point that you could bleed too much boost with the 44mm, which makes sense.

OP, 38mm should work fine for you.

SAMCRO08

The manifold i have is a goautoworks miniram and i was also considering a jgs 40mm wastegate. I read good reviews on that wastegate and they come with a 38mm flange