Thread: Turbo size help

i personally think its worth it and its more then 300rpm difference

Soooo where does it spool? (RPM)

I'm making 400hp with a hks gt2835r and spools quick

on what motor?

I'm all about the sc6262's after seeing what they did on my builds

Its a bluebird block bored to 87mm, Wiseco pistons, eagle rods, knife edge crank, greddy 1.8mm headgasket, 3 angle valve job, port and polish, shaved head, hks 264/264 cams, etc... Running 20 lbs of boost

interesting

Does it sound off. 399whp / 365tq. That's what the dyno said. Lol

i wouldnt waste my time with a 2871r but every one this forum like small frame turbos, if i am looking to make 400 i wouldnt want to be squeezing the life out of my turbo to do it.

with that being said a 30r isnt a bad place to start if you want a t2 sized turbo, otherwise i would go straight for a t3 t4 based turbo and make that 400 easily without running the turbo on the edge of its efficiency range



precisions 6262 is a real nice turbo for around the same price as a 2871r, older sc61s are just as capable,

garret make decent t3/t4s and t3 60-1 turbos


idk why these guys like playing with small turbos its not like our engines cant spool a mid large frame turbo easily

i spool a hx40w no problem what so ever, every since i walked away from small frame turbos i walked away from alot of problems

This is not how turbo bearings work.

Spool time is based on exhaust energy, weight of the shaft its having to turn and restriction in the shaft.

At any given rpm the exhaust energy is the same given a journal bearing vs BB turbo of the same size.

So take two identical sized turbos one journal one bb, The bb shaft is only going to take very very slightly less energy to turn the shaft compared to the journal bearing.

Here is where the bb shines. Gear changes and respool as the journal bearing shaft will slow down significantly faster while the bb will retain alot of its shaft speed during shifts making respool very quick compared to the journal bearing.

Thats about the only advantage to a BB turbo really.

Its been dyno proven that there is only a 2-300rpm difference in spool time given the same size turbo just one being a journal and one a bb. Again proven.