Great info Howard! Thank you.

Quick question, are compressor maps a function of only the compressor wheel? What I mean is, if I took a GT4082 and put a GT4088 compressor wheel on it, could I assume that the turbo should flow the same as a GT4088?

 

compressor maps are a function of a particular compressor wheel and compressor housing A/R.

how the compressor wheel is driven relates to the hotside of the turbo and the engine exhaust flow characteristics.

both sides of the turbo need to be properly balanced as to size of wheel and housing. the housing sizing is as important as the wheel sizing.

there is a wealth of info on this site to help guide you as well as some excellent vendors and tuners but it is extremely important to make all the right decisions as to the components that make up your turbo.

howard coleman

 

Howard coleman i am a little confused here a larger turbo then the 1 that i am running made less power with more boost and then Pluto says this turbo is to small to make the 400hp mark!
My R-85 has a 61.5 inducer and an 84mm compressor wheel compared to the gt 40s 64 mm inducer and 88 mm compressor it should have no problem making the 400 mark
mine hit 417@15 on 93 octane with a restrictive 2.5 inch exhaust id amagine its a little more now that i have a 4inch downpipe and 3 inch exhaust can you clear this up for me my afrs were also in the low 11's

 

please ignore my previous post just realized i was looking at the wrong gt 40

 

the R85/HT300 is an interesting turbo as it has a 1 to 1 cold to hot area ratio.

the compressor is 6.92 sq inches and the turbine is 6.92 sq inches... comparatively a large hot side... i think that tends to be a good thing for the rotary. the to4r has a cold side 1.18 times the hotside and the gt4088 is 1.13 for example.

on my twin TO4 setup i run a 1.10 ratio and at one bar of boost i have only 17 psi of exhaust back pressure. big exhausts work well on the rotary.

as far as your r85 making 417 at 15 psi.... that's right on the money near the max at that boost level.

the r85 makes 56 lbs/min at 15 psi. 56 lbs/min X 14.471 = 810 cfm/ 1.92 = 422 rwhp.

max is 64 lbs/min at 33 psi. 64 lbs/min X 14.471 = 926/ 1.92 = 482 rwhp.

howard coleman

 

Nice number Moehler!!

Howard, thanks for posting up the info and the formulas for figuring hp levels.

Zach

 

Here's another interesting tidbit... according to measurements I got off my 87 TII wheels, the ratio of the small side of the turbine to the small side of the compressor is 1.25. (the ratio of the big sides is 1.00).

I know that the puny stock 87 wheels might not be directly applicable to running 15 PSI and making 400 rwhp, but it's still interesting

 

nice

 

i had this turbo but with a 1.0 hotside i never ran it as i sold the turboand car but i got the car back would i expect the same numbers if i went with this turbo again

 

looks good

 

3 years ago

 

 

http://www.youtube.com/watch?v=jooJc...eature=related