Trying to get an idea of how much boost I need to pull out of this turbo to achieve 350-400whp on a built 2 liter.

Please post your build as well, dyno charts are a bonus

Also tell me how you like the turbo and what your impressions of it are.

 

It's about 50lbs/min, so about 16-18psi of boost pressure assuming a good volumetric efficiency of a VTEC head in order to get about 350-400whp.. So a bit better than a T3/t04 50 "trim" turbocharger. Not many use that turbocharger on this forum. Sadly, people look at peak power and go straight to a GT3076R.

 

I was afraid you'd say that, about this forum I mean. I don't want to be like everybody else and buy the biggest, baddest, most popular turbo just to say that I have it and make 1,000,000 whp. I am trying to really do my research and not just depend on whatever everyone else says but actually LEARN why and what kind of turbo I need for my horsepower and driving style goals.

That said, my real question is whether the gt2871r or the gt3071r is better suited to my build. I realize that these are relatively small turbos compared to what people are putting on their cars these days, but that's by design. I want a broad powerband from mid-range pulling nicely through the top end to see between 350-400whp. I'm afraid the 28 series will "run out of breath" by the time I hit 8-9k but I will lose responsiveness with the 30 series or surge at lower rpms. Any ideas? I should mention that I am new to boosting so forgive me if what I say seems stupid.

 

you are probably right about the 28r falling off up top at 400whp. if it will even reach it. the spool time between the two turbo's you mentioned are probably only a couple hundred rpms.

 

The GT2871R is pressed for 400whp on that setup. Your initial thought process is correct. The GT28R could only do about 300whp, but the GT3071R could do more and with better powerband.

 

I laid down 353 on a gt2860rs. This is maxed out. Go with the gt3071r.

I just picked up a GTX3071r .62 A/R. Haven't gotten it on the car yet but I am excited :D

 

That's good to know, I feel better now lol.

I bet! That is an AWESOME turbo from the research I've done, I just dont have the stones to buy one. Hey, let me know what its like when you do get it installed, if you convince me, I might just change my mind.

I had a better feeling about the 30, thanks. I was also wondering if it was worth adding the ported shroud compressor housing option, does this actually help prevent surge, or is it all for show?

 

It helps with overspeed past the surge line, not surge from a malfunctioning Blow Off Valve

 

Ok, thank you for letting me know.

 

How much of a difference is there in spool when comparing the gt3071r and the gt3076r?

 

i think my friend made around 425 on a 30r with a built 2.0 and 91 octane

 

I am contractually obligated to reply to any and all GT30 threads. Check out the GTX3071.

 

I went with the GT3076R cause it will make the power I want now, and the power I want to make later.