T3/T4 50 trim: .63 vs. .48

[turtl631]

I think I want to get a turbo with a smaller A/R to get better spool time since I'm going to stay stock block and not use close to all of a t3/t4 hybrid's potential. I was just wondering if anyone has used both turbos and could comment in the different characteristics of them. I want to stick with a 50 trim in order to have an efficient turbo that won't turn into a heat pump at higher boost, which is why I'm not going with a T25 or T3 or something small like that. Thanks.

[WDRacing]

It really depends on the HP level you want. If your not going for more then 275-300, then the .48 will work fine.

[klattr1]

the .63 ar will have a little more top end but the .48 ar will boost sooner. most people end up going with the .63 ar because you can use the turbo just fine even with a built motor all the way up to 22-23 psi.

[hannibal]

Would you use the stg 3 wheel for both turbines?Do you see any problem with the .48AR holding 15psi til 6500rpm?

[:: orion ::]

The .63 spools to 12psi on my car by ~3200-3300...how much faster do you want?

I think if you want 15psi froma T3/T4, then you're shooting for over 300rwho...then you need the .63 A/R, Stage III.

- Brian

[WDRacing]

Yep, if your going for 15 psi, then a .63 is the way to go for sure. The lag really isn't that bad at all anyway.

[turtl631]

I would say I'm shooting for around 300, give or take. I don't see the point of only boosting 7 or 8 psi on a t3/t4 hybrid with 550s and a good ecu tune..seems like a waste. I will never build the motor b/c I don't have the funds for that, nor the desire to make that much power with this car. The reason I was asking about the smaller A/R is that most people say a t3/t4 50 trim is good to around 400 hp, and to me that indicated that using one for 280-320 is underutilizing its potential, and therefore one of the smaller 50 trims woudl serve me better. I like mountain roads and autoX mostly, don't really care about drag unlike a lot of people on this board, so I guess I'm going for a more responsive setup than a lot of members here. Er, responsive for a t3/t4..I know it will never match something like a t28, but I want somethign more efficient. I've seen a few low 300s stock block KAs on this board, which is why I'm aiming around or slightly below that horsepower target.

[:: orion ::]

Well, if auto-x is your goal..the sacrifice in top end may be worth it to go with the .48...it will hurt the VE up top, and 300rwhp will take a couple more PSI than with a .63...but it may not come on like a kick to the ***.

When mine spools, I gain ~100ft'bs over ~300rpm or so...and it's kinda "twitchy" sometimes (i.e....mid-corner, 2nd gear, ~45mph on the auto-x course...breaks 'em loose every time). I would prefer a smaller turbine, and "smoother" spool (think: SR20) if I focused on auto-x.

But I prefer road courses, HPDE, stuff like that...and I like my top end.

So, there's more food for thought!

- Brian

[Projex240]

Have you dyno'd that car on 12 psi yet? Id like to know what Hp levels the turbo ahs made at the setup--mine is identical save for the manifold.

-Josh

[kclo4]

I was actually considering this same turbo in .48 a/r 50 trim.

My goal is to keep the engine completely stock, dont even want to change injectors, MAF, etc etc.

So my goal is to max out the stock fuel and ignition or 200whp/220tq, whichever comes first.

I want a very responsive fast spooling setup but I guess I will be making out at 6psi or so.

Is there any other turbo's that will work better for this setup?

[WDRacing]

I was actually considering this same turbo in .48 a/r 50 trim.

My goal is to keep the engine completely stock, dont even want to change injectors, MAF, etc etc.

So my goal is to max out the stock fuel and ignition or 200whp/220tq, whichever comes first.

I want a very responsive fast spooling setup but I guess I will be making out at 6psi or so.

Is there any other turbo's that will work better for this setup?

I'd atleast use a FMU. Even a 4/1 rise in pressure will be better then using nothing. They are to cheap not to use.

[kclo4]

I didn't even know what a FMU was until you mentioned it and I read up on it. Sounds good for what I want to do. I dont want to upgrade the fuel pump so it would have to be low like 3:1 or 4:1 as you said.

I am trying to keep everything less then $1500 and more like less then $1000 if I can. Probably wont do it till the end of the year and the next $1000 that I can drop on car still will go to a LSD.

[klattr1]

I didn't even know what a FMU was until you mentioned it and I read up on it. Sounds good for what I want to do. I dont want to upgrade the fuel pump so it would have to be low like 3:1 or 4:1 as you said.

I am trying to keep everything less then $1500 and more like less then $1000 if I can. Probably wont do it till the end of the year and the next $1000 that I can drop on car still will go to a LSD.

why dont u want to upgrade a fuel pump?do you like pulling motors out of engine bays for a hobby?

take the time, money, research and do it right.

[hannibal]

Wasnt trying to hijack, turtle.

Very good thread...

[KATwo40]

If you're looking for the 200hp range, I have a turbo/FMU to sell you. Hit me up sometime for discussion. [email protected]

[:: orion ::]

The .63 spools to 12psi on my car by ~3200-3300...how much faster do you want?

Have to correct myself...it's more like ~3600-3700 to get to 12psi. (Drove the car ~200 miles today, taking note of such things)

Sorry for the misinformation above.

- Brian

[sil80drifter]

I use a T3 that is considered to have a close to 1 A/R on the turbine side (S4 RX-7 turbo). It's like between 0.95 and 1, nobody knows for sure (odd, yes I know). Actually I'm gonna shoot TurboCity an email and ask, since they've balanced my wheels.Lol, back to the point. The point is that I get 10psi by 3500. My compresor is rather small/medium T3 sized, so you have an idea. I'm not sure if rebuilding the turbo will help decrease a bit of lag, or an EBC will do that (actually I know an EBC will do it), but to me it's a bit too late, so I'm seriously considering the EB (Electronic Boost Controller), to help me a bit with the lag. Either than or I'm welding the turbine inlet to make it smaller for better gas scavenging.. lol.

sil80
Modified by sil80drifter at 9:57 PM 2/7/2005