well i broke the original engine.so now im swaping out the 2.8 for a bored 3.1
,my original turbo was a t3/t4 hybrid to4e stage 3 57 trim .63/.50.well with the new motor i wanna do twins and ordered a second matching turbo.but i was just thinking about the ar on the hot side, should i have gone with .42's on the hotsides with the twin setup?vs the .63 i used on the single setup.btw i will be spinning this motor to aprox 7k like i did with the 2.8

 

why go to 7k if you dont need too?

Im not really a turbo genious, but on a v6, one turbo would be plenty if properly sized.

 

well for one the v6 likes to rev high,yeah i could stick with the single turbo,but **** it i wanna stick 2 on it this time,besides twins should alow me to run higher boost and keep the charge cooler

 

I can understand the cool factor of twins, but you will probably want to use smaller turbine housings, and maybe even a smaller compressor. What trim are the turbine wheels? What HP are we shooting for here?

FWIW, I have a 3400V6 in my Z24 which produces 328HP/352TQ to the wheels with a single TO4B/T3.63 remote mount turbo. Peaks were quite low at 5000 and 5500 respectively.

How'd the 2.8 perform on boost for ya? (before it broke )

 

they are to4e's stage 3 57 trim,the 2.8 was a blast,never had time to have it dynoed or run it,what happened was the flywheel cracked and i quess from the vibrations,or just when the flywheel finaly broke all the way,it hurt the back of the crankshaft,,im trying to go big with this,ive already invested in custom forged pistions,and the 327 smal journal rod swap,and acording to gm the stock crank is good for 400+,i still have to make the switch to sd from my maf setup.but im looking to throw 18#+ at this new motor,along with a 35 shot of nitrous,and methanol injection

 

Sounds like a nice project.
I would also say the hot sides might be a bit on the large side for 1.55-1.6L and 7k. My 2.0 has the same hotside but with a T04E 50 trim and it hits ~20psi by 3500rpm and makes decent power to 7500 easy (which of course has a lot to do with the rest of the engine, but that is to say it's not a restriction at 7500 by any means on my car). Yours in that config might not hit full boost until much later. Lots of B16 (1.6) Civics run that size turbo up to ~8500.
I'm sure yours would make good power as is, but .48 housings would probably give you a more usable RPM band.

A single 57 trim wheel will easily support 500hp, so you also might be better off with smaller cold sides too, unless you want to go all out later on and don't feel like upgrading again.

BTW, if you went with one 'equivalently' larger single, it wouldn't make any more heat at the same boost and power level than the two.

Good luck with it.

 

thnx man,well i relized soomething a bit ago i can run the twins until i convert to sd anyway.well im not getting my donor car for prolly another week,so im just tossing the single back on,which really sux cause i had already mounted the dual inlet fmic and started to plumb the pipes.atleast all the **** for the single setup is already fabed,and will pretty much bolt back into the car for now.except for the fmic to tb pipe which i am rerouting.ill post up pics tom of it,caus eim staying late at my shop tonight to try to get most of the work done,so that i can take the car out late tom afternoon,as long as it isnt raining anyways