Hey guys, is there any sort of general idea as to what size of wastegate should be used for various sizes of turbo? (i.e. is there a cfm or boost level relation?)

In my specific case, I'm getting a GTX3582R Billet turbo and I'm concerned that a Tial 44mm might not flow enough. I know manifold has a lot to do with it as well, I'm just wondering if there's a generally accepted way of knowing what I might need...

 

well. 44mm isn't enough, next step is 50mm but that isn't really a step.
so the real question comes down to 60mm or dual 44mm?

https://www.rx7club.com/single-turbo-rx-7s-23/tial-60mm-941654/

 

lol any size WG will work..... :P its going to depend on the boost you run will determine the WG size.

If you only running 12-14 psi on that turbo Id say your 44mm is going to struggle.

 

I would agree with Havoc.

I have put some of the 44 TIAL's on customer cars and them are OK for 1 BAR (about 14 PSI) of boost, even on a big blower. If you go above that, it will be a different story!

REgards
Iwan

 

You mean below that. You can get away with a smaller gate if you run higher boost = less exhaust flow out the gate, more being used to generate boost/going out the turbo.

I believe Havoc was alluding to this when he said, "you'll have issues if you ONLY run that much boost."

OP: a 44mm is a decent sized gate. I don't know of any hard and fast rules, but if you intend to match the boost to what the turbo is made for and your manifold doesn't suck, I think it could work. Now if you're asking a question for a gate you have not purchased yet, always buy big.

 

I been thinking about the same thing. I am gonna run the new efr 9180 with the Full-Race twin scroll manifold and for porting i am just doing a large street port and not so clear on what wastegate size I should go with. I was thinking two 44 mm.

 

why not dual 38mm? Less cost, flow more than a single 50mm but less than a 60mm

 

yes an no. to create more boost, more exhaust gas will have to go through the turbine. but now the compressor is putting out more CFM. and even more exhaust gas is produced thus you'll need a larger wastegate.
yes you can turn up the boost until the you reach the compressors max efficiency and it stops increasing CFM, but your already loosing horsepower at this point.

point in fact. i had a 44mm tial wastegate
TO4E 12psi = zero creep
TO4E 15psi = 1psi creep

TO4S 12psi = zero creep
TO4S 15psi = 2psi creep

 

I won't argue with experience, but conventional wisdom recommends big WG's to people that have dual maps and run low boost on a big compressor around town. But again, as I said, experience trumps all.

 

i second this!

 

44mm will do just fine! Just put your perferd choice of spring into it and you'll be okay. Although sometimes going bigger is better but clearance will be the next thing to think about.
G/L

 

i'd say why risk being too small? go bigger, no harm in that.
plus if you ever go with a bigger turbo, you won't have to buy another wastegate.

my 60mm is going to be way overkill. which is another rule of thump. if you build the motor to handle must more then you can throw at it. it'll be less likely to fail with a smaller load.

 

i have a tial 46mm gate im selling if ur interested lol

 

Generally speaking the smaller the turbine housing (higher EMP) the smaller the gate you can get away with. Also the higher the boost the smaller the wastegate you can run. Big turbines and low boost take a lot of wastegate flow. I am running dual 44s and i can't get any less than 22 psi of boost.

 

On our FD we were running a 44mm Tial and we had uncontrollable boost. The turbo was a Garret GT35R with the Tial 1.0 hotside. We found that it would boost up above 20 lbs regardless of the spring in the wastegate. This was with a 4" unobstructed exhaust.
The new setup uses a Tial 60mm and the boost is solid at the spring pressure. If you ensure you have a good, unobstructed flow and a large enough wastegate (60mm) you should have no problem.

-Trent

 

Manifold is the biggest influencing factor here!

Too small runners and your boost will be out of control. The bigger the pipe the more control you have with a smaller wastegate. I use our own 60mm Raceonly gates and regardless of manifold never had a car overboost and any boost level. Cant beat a good gate.