Hello,

I have read on how A/R's can effect the boost threshold / spool response / flow and what not, but I have not found anything online with a similar setup to mine to reference how x y z will react. So I ask for your experience / expertise to help me out here.

What I have:
K20 with Prayoonto stg 3 cams
EG
GTX3076R Gen 1 .63, Ext Gate, sidewinder manifold
Aim for 500whp

I want to change the rear housing because gut feel the .63 will be way too small - especially when this motor pushes a lot of air and breathes a lot better at higher RPMs (however a 3076 might run out of puff, I am not sure on this?).
Garret offer .61, .83, 1.01 A/R rear housings (Vband). Based on my limited knowledge, 1.01 would be ideal for the motor to rev harder, but will it compromise everything else? (or will I not even notice it)

Any advice as to .83 or 1.01? How will each react?

I dont want any comments as to why I did "x" to the motor, or "that turbo is way too small for that motor". Its what I have. Will I move onto a bigger turbo later? Do I even need a bigger turbo? I'll let you know once I drive the car and enjoy it.

Thanks in advance!

 

Also, I might have kicked myself in the nuts with the big cams, we will see how I go with them, and then will decide if I put K20A/2 cams back in...

 

Id' change the exhaust manifold before the turbine housing. (to a tubular, longer runner manifold)

 

Woops, I may have got mixed up with the terminology. Its a sidewinder. Mate fabricated it based on his JDL side winder..
Looking at google images, that means its a tubular? :D

 

High VE engines have a lot of wastegated gas. Id say if you allready have the .63 try to max it first. I have a feeling it will max the same time with the turbine wheel on a K20A2.
Other than that if you REALLY want to have best results without changing turbo you must halp that turbine wheel extracting every last % of its efficiency via adding flow. And that only the 1.01 housing can give among with the obvious lazy lag- on/off situation.

 

Looks like the A/R choices you're using are all Ni-Resist, also. I agree with. Balor_Gr. Stay with the .63A/R right now. That is hard to max out the turbine gas flow amount with that turbine wheel in that sized housing.

If you're trying to go offer 600whp, you are at a point where you need a different turbocharger entirely, anyway

 

Not too crazed about having the best results as I just want the car on road with minimal money. But if I can change something small to improve the result, then I'll do it. But if 1.01 will be noticeably lazy then I think I'll pass.

Well that is surprising to me.. I shall just use it as is then!

Will not be going over 600, especially on this turbo as I know 600 is right at the top of its "rated" power. 600 is getting out of hand on a street fwd anyways

Thanks for comments so far

 

Plenty of people are using .63 up to about 700whp. I believe ~1050whp is the highest I've seen with .82.

And no, you won't be struggling with the top end whatsoever.

 

By the way id easily swap that gtX3076 G1 compressor for a gtx3071 one. Maybe a compressor backplate and compressor howsing Paired with the correct G1 or G2 GTX3071 compressor. Perfect combo with the gt30 turbine wheel and .63 housing

 

I would also agree with this. I've been able to change those relatively easily to better combination of backplate, compressor cover & compressor wheel for a more responsive system, using that great turbine wheel.