i finally had a chance to tune my boost on the new selenoid, coming from MBC i decided to use the GM Boost Selenoid instead, but cant stop the boost from tapering up top. I decided to run 25psi of boost on my 100oct setup but no matter what i do it kept tapering from 25 to 21psi up top.... pls let me know where to make adjustments from here.....




MODS:

Ported Head
Ported Exhaust Manifold
Titek 02 housing
Stock VIII Turbo with 10.5 hotside
Turbo Back Exhaust with Test Pipe
Weapon R Upper/Lower Intercooler Pipings
Spearco FMIC
K&N Open Filter
RC 750 cc Injectors
Walboro Fuel Pump
Okada Coilpacks
NGK 1 Step Colder Spark Plug
100 oct fuel





or is my VIII turbo max out??


TIA

 

Nature of the turbo plus the ported head and cams as well.

 

When my wastegate hose was off last year on my car (TBE + bushcur header + K&N drop-in etc.) the stock 05 turbo would max around 29psi and taper to about 21/22 psi according to the JDM map. So if you want to hold 25 looks like you need to get a different turbo.

 

its that mean stock turbo is really max out? so is time time to get a bigger turbo?

 

21psi @ redline is really the limit of the turbo.

and even then its out of its efficiency range.

if you want more than 20psi @ redline, get another turbo.

 

LIES!!!

 

ok first time ive seen anyone make more than 21ish...

how?

 

Evo 8
Stock cams
Ported to hell turbo
GM 3 port
3" exhaust no muffler
(track car)

With cams and more flow the turbo won't hold that much.

 

oh well, ported turbo...

 

so to hold more boost, instead of going to a different turbo, just get it ported and should hold atleast my boost all the way?

 

He's on stock cams + FP Green turbo. Guarantee if he throws on some cams he wont hold that boost. I hold 24-25psi @ redline from a 30psi spike(stock cams)

 

It is not a green, it is a stock turbo that has been ported. Why would I post a boost plot of a green when we are talking about a stock turbo?

 

You have cams and a ported head, I doubt it will hold that kind of boost.

It's not a bad thing, boost isn't everything and doesn't tell the complete story.

 

in fact it tells none of the story. mass flow rate is the only story. no matter what the point is to get more air into the motor. I know I'm not telling you anything razor, but sometimes it needs to be said that explicitly to everyone.

 

not really...

what about air temps?