JDM evo 8 GSR
-stock turbo and bottom end
-evo 9 BOV
-GSC s2s with hi rev springs and ti retainers
-ets 3" front mount
-tomei catback
-PTE 1200cc
-walbro 255
-dc turbo downpipe
-ets licp
-EBC
-arp headstuds
-cop kit ( what gap should i set my plugs to with a cop kit?)

will get tuned on 94oct

 

Place your bets:

The stock turbo is really holding the no.s back

I say: 335 DynoJet WHP at 25 PSI

 

The general gasoline formula used for centuries (decades?) has been:

cidxrpm/3456 = cfm * .069 = lb/min corrected
lb/min * pressure ratio = total lb/min * 10 = bhp

ex,
122cidx8000rpm/3456 = 282cfm * .069 = 19.4lb/hr * 2.0 = 38.9lb/min = 389 brake horsepower with a pressure ratio of 2:1 (14.5psi of boost)
If we multiply by .88 (12% drivetrain loss) we get 342rwhp
more boost:
122cidx8000rpm/3456 = 282cfm * .069 = 19.4lb/hr * 2.4 = 46.5lb/min = 465 brake horsepower with a pressure ratio of 2.4:1 (20.3 psi of boost)
If we multiply by .88 (12% drivetrain loss) we get 409rwhp

The equation assumes 100%VE ('big' enough cam/head) and that the turbo is not running off it's map to the right (out of breath)
I notice you are using an OEM turbo so likely it will run out of breath before hitting anywhere close to those numbers at 8k rpm,
The correct way to compensate for that is to find out how many lb/min your turbo flows, and integrate that into the formula.

 

+1, I think your right on the money.

 

Is your turbo the 9.8T or 10.5T version?
Are you using a cat or test pipe?

 

Stock evo turbos won't hold more than 21 psi up top. They can be forced to boost more with stiffer WGA but the added heat won't let it make any extra power.

 

Don

We need your WHP bet please

Heres a thread where guys were stating their 8 pressure settings:

https://www.evolutionm.net/forums/ev...o-8-turbo.html

 

My guess would be 300whp with HFC on 9.8T
315whp on 10.5T

 

from what i remember, it says 9.8 on the rating plate of the turbo and im running a test pipe

 

damn i was hoping id get 350hp at the minimum thats why i went with the big boy parts. All that reading that i did about on how to mod an evo and i spent the less amount of time on the turbo topics LMAO

question is though... fp green, evo 9 or tomei arms, which turbo do you guys recommend?

 

You have a lot of choices. Many of us running the stock block keep things super simple.
Theres a whole group of us running the stock 9 hot side w/the FPHTA71. This setup w/S2's gets us into the mid 400's on E85 (Dynojet)
Unfortunately FP really raised the price on the HTA71 unless you can find a used one?

A Green would be the winner setup for sure

 

If you are going to run turbos from manufacturer, FP Green is best on your list. I will be upgrading a Tomei with an aggressive 20G in a few weeks. I like how beefy the Tomei hotside volute divider is.

 

Tomei from factory uses a cast 20G, so it's not any better than FP 71hta. But an aggressive billet 20G will give FP Green a run for the money.
For reference, left is oem IX and right is cast 20G..

 

Here's the aggressive billet 20G (right) vs Black HTZ (left).

 

With cams and 94 octane it should make ~375whp.