Wastegate sizing...

[nsngarage]

Is there a certain way to figure out what size wastegate you would want on your car?... I know it is different with different turbos and such... but is there a general "guide" to sizing them?

I know how they work and all, just dont really understand how to match them up with a turbo..

I've searched the forums and can't find the actual answer im looking for lol...

If anyone is well versed please teach me!

thanks!

 

[pln]

I havnt seen any certain way to calculate this, only roughly what determins wastegate size. Differences between compressor and turbine, like if you have compressor thats big in relation to turbine you will faster build more pressure in exhausts. Exhaust house design on turbo matters.. small a/r will build upp more pressure and need bigger w-gate to evacuate gases. But all this is very depending on what boostlevel you are planning. More boost=more exhaust gases.

This is just my conclusions. Im no expert so everyone else feel free to fill in. I could see my boost taking off at 6000rpm with gt35 1.3bar(not sure of a/r),, and it could be other things that caused the problem but i decided to play it safe and go for 50mm w-gate.
If you are uncertain... just go for the bigger w-gate.

 

[IJ.]

The bigger the AR on the turbine the less gate size is needed

Opposite if you're trying to run low boost on a bit turbo with a normal AR.

 

[foreverpsycotic]

Is there a point that is too big, and will hinder performance?

 

[X-man]

I run a 44 mm Tial gate with my GT42 with a 1.01 a/r on the turbine side, I ran a 40 mm HKS gate on my 67 mm turbo with both a .68 and a .81 a/r turbine housing and a p trim wheel. I have run boost levels on both set ups as low as 13 psi to as high as 30 psi with no creep or control issues. There is a 15 psi spring in the Tial gate and was a 10 to 11 psi spring in the HKS gate.

As a side note I run a 60 mm gate on our turbocharged S10 with a 383 CID and an 80 mm turbo with a 1.30 a/r on the turbine side with a 96 mm wheel and have run as low as 6 psi on it to as high as 18 psi.

 

[Nick 95 6sp]

Is there a point that is too big, and will hinder performance?

as a "data point" that might reflect a larger than usual wastegate with a smallish turbo, my PHR Stg1 turbo, which is a 60-1, on my modified Turbonetics cast manifold, uses the HKS 60mm GT wastegate. It controls boost perfectly anywhere from wastegate spring boost of 17 psi to over 30 psi.

I think the type of boost controller also plays a role...what I mean is that some boost controllers can pulse the signal to the wastegate which helps in controlling it to what amounts to modulated flow rather than just open and closed. I think my Blitz SBC-iD which has two quick acting solenoids helps control boost better than some other ebc's for that reason.

 

[leecheater]

http://www.supraforums.com/forum/showthread.php?t=565111

 

[nsngarage]

good info, i kinda knew about the a/r being bigger means less of a wg.. Just wasn't sure exactly how to calculate it all... But appreciate all the info! I'm going to do some more research on the spring parts and all just to know that I know what im doing lol...