AaronZ34

So 8psi is the same airflow no matter what engine it's on?

busa4

8 psi is a measurement of pressure, not volume of airflow. dont confuse pressure with volume. two different things.

AaronZ34

But if boost is volumetric efficiency, then boost is a measurement of airflow in an engine.

busa4

cfm is a measurement of airflow in an engine. VE is a measurement of cylinder fill and its measured in %. boost is a measurement of air pressure and its measured in psi.

VE goes above 100% as the boost comes in. its just a calculation. all the math in the world is not going to give you exact numbers. it gives you an idea of what you can expect. there are too many variables, it will never be exact.

VICTORY_OR_BUST

well i guess im gonna be looking for a t3 what trima and such do you recommend and where is a good place to get em? im new to this so i dunno but t3 seems to be large to me but i could be wrong?

busa4

you have a massive engine. 1640cc to be exact. go on the garrett site and look at different compressor maps on all the turbos they have available. whats your bore and stroke? 3.87" x 4.25"?

VICTORY_OR_BUST

101 mm bore and 102 mm stroke with an 8.7:1 compression ratio. now ive looked at a few t3's they look to all be rated for like 350HP now im going to try and attatch a few images of two currently marketed turbo systems on bikes similar to mine, black bike is mine exactly, silver bike is same motor but different body style, like i said im new, but those t3's look massive compared to these little guys, and it was my understanding that the smaller it is the quicker it will spool. my objectives and reasons for this project are 1) wheelies on a v-twin, not all the time everyday but i would love seing someone ---- when i do one 2) i wanna wax a couple rockets in the 1/4 i have the bottom end and i have low end high lift cams in the bike so the grunt is there its the top end holy ---- im FLYING ability to break tire loose a 70 mile an hour that i want, on to the pics of these bikes, fyi they get 5k for these setups, and the trask is ------ ugly as hell and i wanna set mine up like the aerocharger

busa4

i cant tell there size from the pic but they do look like t3 turbos. you stated you were looking for power above 3k rpm. i checked garretts site and they had a perfect smaller turbo for your setup. the gt25. it uses the smaller t2 inlet flange but boost will spin up at ~2000 rpm and it will be at its best efficiency range at 6000 rpm which is what you were looking for. there gt28 series turbos will be very efficient at 6000rpm as well but they wont produce boost till ~3000 rpm.

check out the site and see which turbo works for you.
i calculated your pressure ratio is 1.44 at 6 psi boost and your air flow(lbs/min) is

2000 rpm 4.5
3000 rpm 6.7
4000 rpm 10.5
5000 rpm 12.7
6000 rpm 15.2


plot these numbers on compressor maps on the garrett site and see what works for you.

VICTORY_OR_BUST

---- man you have done this before, i was looking at the t25's initially as well so its good to know i was ballpark anyway, so your thinking i should be at 6psi rather than 8 huh? fair enough you know more than me now i dont have my rev extender yet but when i do the safest you can go is 6400 so do you think it is efficeint to run a turbo that boosts at 200rpm when all i have is 6400 to work with? i mean i think it is cause i realy dont wan the thing boosting when im just cruisin through down but when i bounce on that thing i want it to take the ---- off

busa4

the turbo will be most efficient at 6000 rpm. i wouldnt boost it anymore than 6 psi as you will need an intercooler or meth injection after that boost level.
boost from 2000 - 6000 rpm will be fun. you probably will never reach high rpm boost since it will scare the ---- out of you at low rpm boost.

there is no load on the engine while cruising so there will be no boost.

engine life all depends on how your tune is.