waste gate size

[somedude_001]

on a local racing forum someone is selling a (see below)

Tial 38mm WG
wastegate is brand spankin new 175 obo
polished stainless (no color). spring should be .5 bar

although .5 bar is not enough, i could just change out the spring right, and is 38mm big enough?

 

[UnderPSI]

I think TiAL is the only way to go as far as wwastegates. Have had a lot of trouble with other 'gates. 0.5 bar is 7psi, not too bad. You can either change the spring or just buy a boost controler. A brand new TiAL is worth every bit of $175.

 

[somedude_001]

ok i'll get it i just wantewd to make sure that 38mm was large enough.

i was origionaly planning on a 9psi wastegate spring but i was to have 9-12psi at teh manifold so i have to account for the pressure drop from the inter cooler and piping... my point is i'll need another spring. thanks.

 

[UnderPSI]

If you use a boost control, you won't need a spring. You can run from 7psi to as high as your turbo will put out with the turn of a ****, or push of a buttom, depends on what type of boost control you buy.

 

[somedude_001]

can you give me a quick lesson on boost controlers? how do they work, i know mechanical ones are very popular in my area and I have herd that electronic ones are expensive and i don't like expensive and i'm thinking i want full boost all the time and that i'm not going to want to dum it down.

 

[UnderPSI]

You have to understand how a wastegate works. Boost from the motor enters the port of the boost controller, this signal forces the diaghram to open the actual valve. By limiting the amount of boost signal to the 'gate, it opens later giving you a higher boost level. All boost controlers do is bleed off soem of the signal pressure to get the psi you want. While a manual boost controller is cheaper it will make less power, because it will let the wastegate start to open earlier, bleeding of a little pressure until it gets to the pre desired actual boost pressure. The electronic boost control keeps the wastegate shut until you hit the pre set boost pressure. There by giving you a little better torque curve.

There are benefits to turning it down. Can run a higher setting for race gas and a lower setting for pump gas.

 

[somedude_001]

won't using a spring keep wastegate closed untill the desired pressure? maby open up a bit earlier but wouldent it still be perfectly safe? all i'm thinking is if i can save a few hundred bucks it would help out a lot.

 

[SHO--ripper]

Just as long as you have a spring in your wastegate that is less than the desired level of boost, and you have a boost controller you'll be all set.

 

[somedude_001]

that is my question i guess is do i need a boost controller

 

[UnderPSI]

No you don't. However, you can get a manual controler for not much more than $20.

 

[somedude_001]

ok so that explains why this wastegate has such a small spring in it, the spring in the wastegate is you base PSI that your setup runs and a boost controller will let you go above that... i understand now thankyou for your help!

 

[UnderPSI]

You can by a spring for almost any psi. They work fine, the controler is a little more user freindly to adjust boost with. Hey, no problem.

 

[somedude_001]

i woudl like to just go balls to the walls and run like 12psi and have it tunned for that and leave it be, my thoughts are that 12psi is enough power to feed my adiction for a while.

 

[UnderPSI]

LMAO! It's never enough when you start talking boost, ands it's so easy to get more boost. I always get out of hand.

 

[Toolman]

FWIW, I am running a 38mm Tial with a 0.5 bar spring. With my Greddy Profec A, it is no problem hitting 15psi, without my overboost button. I would not want a higher rate spring myself. This one allows for some pretty fine tuning of the boost curve, and with the touch of a button I can go back down to 9psi, where the motor will live happily for a very long time.

 

[somedude_001]

i understand you toolman but i doidn't budget this project to have a boost controller, i'm turboing this car on $280 a week from my work, i love this part i've got something in the mail every week and almost everything is shiny! *clears throat* i mean vital to the project.

 

[Toolman]

The Profec A is no longer offered, so you will only see used versions. You can get one for less than $200. Or you can step up to a Profec B for around $270 new. But in the meantime, just using the WG alone will suffice. Get the basics down, you can always add more later.

 

[MerkXRTurbo]

I would reccomend a boost controller either way. When the boost starts to approach the wastegate's limit it will start to bleed open a little. The MBC prevents the WG from seeing any boost at all until it reaches your predetermined boost setting.

 

[Toolman]

The WG is always 'seeing' boost. It is in the path of the air charge.