alperx

The Turbo is a Garrett T3/T4 with brand new internals.
The company that built my turbo is my friend's.
He couldn't find a bigger exhaust turbine for the moment
and it's now built with .48 a/r.





Will be running around 15 psi. Intercooler is 7 Liters.

The problem is :

What will be the effects of the .48 A/R on the motor ?
Won't it be effective around 7000 rpm ?
Will it cause any backpressure disadvantages for tuning ?
Fuel is 97 octane.

My config is :

EUDM b18a2 block (upgraded sleeves - darton spec)
JDM b18c1 head (stock)
stock polished p72 intake manifold
stock type-r throttle body
wiseco pistons
eagle rods
arp head studs
OEM head gasket
custom ramhorn exhaust manifold
3" downpipe & complete exhaust
neptune rtp
compression ratio is 9:1

TheShodan

iTrader: (14)

Its not just the housing that may become an issue, its the wheel inside of it. For most B-series VTEC engines, for the 76 trim 64.9mm (Stage III), a .64A/R is best to use. a .48A/R for lower and power on a Non-vtec engine or SOHC would be a bit more proper.

Depending upon the HP goal, it would be more prudent to bump up a size to .63A/R, so that you can eliminate backpressure

alperx

my trim is 69..

TheShodan

iTrader: (14)

So its even smaller, like stage II turbine wheel size. In that case, it won't matter at this point, as the turbine may create a lot of backpressure from such a small exhaust wheel on a B-series VTEC such as the one you're building.

alperx

well, so do you think it will be OK if I only change the turbine to .64 a/r ?
or do you think I SHOULD change the wheel too ?

TheShodan

iTrader: (14)

Yes, on both. Going to a 76 Trim stage III and a .63A/R is the best option for an LS/VTEC.

Now if I only knew what the compressor wheel is. Looks a bit out of place considering an eyeball's look at the compressor inducer. But that's just an eyeball's look on a screen

alperx

so next question is : How much boost would be safe with this .69 trim turbo , do you think according to your experiences ?

Turbo-LS

iTrader: (4)

its not the boost pressure realy thats the problem its the small wheel accompanied byt the small turbine housing thats going to cause alot of back pressure nd choke out the engine higher in the rpm range. if your going to stick with that turbo it will just be a restriction, That being siad it will still make power just wont be a beast in the top rpm range. I personally would swap it out otherwise wouldnt run more then 8-10 pounds of boost even then probably be a restriction.

AlexDphoto

glad you posted this up on here after your thread got deleted on TI because people were trying to tell some dunce that PSI wasnt really the proper way to set your goals.


I agree that this turbo with the .48ar is best suited for a non-vtec application. Im sure as the rpms climbed you would see this thing choke up top

Turbo-LS

iTrader: (4)

PSI isn't the proper way to set you goals. You can make 300whp on a small turbo at 20 psi or 300whp on a properly sized turbo on 10 psi. The amount of boost you run isnt your goal unless you just want to say you are running 20 psi for the heck of it. the goal is the torque and hp you want to make and where in the rpm range you want to make the power

alperx

thanks for the help. so I won't make a mistake, and I'm sending it back.

will try to get something else..

AlexDphoto

know how many times we tried to tell this guy that and he came back with more elaborate reasons why psi matters and how two turbos at 10psi no matter how different will yield the same power?

some people

alperx

eheh

how about GT2876R ? with .86 a/r

TheShodan

iTrader: (14)

What are your power level goals? use of the car? type of driving you do?
Instead of just throwing out turbochargers to get an election-polled opinion, it would be easier to state what it is your REALLy want to do.

(Not to mention a .86A/R uses a T2 flanging system for an internal gate)

alperx

my goal is to have a 350whp street car with long durability.
I'm giving you this turbocharger because it is on sale here in Turkey. In this country everything is more expensive than in states, so I can't just buy anything I want.

alperx

Hope it doesnt break out : I found a used GT3071R