Turbo size for 3400

[3400beretta]

I have been looking around, and noticed that everyone is using very different turbos for the same application. Now I have a 3400 in a beretta, and I want to turbo it, I will be building the motor to handle at least 20lbs of boost, and I was told that a t3/t4 hybrid would be the best route, but they come in many sizes and I just wanted some suggestions. the car is standard, I currently am running the 3.94 fdr tranny, but I think with a turbo, I should go back to the 3.61 tranny, as wheelspin is ridiculous even with drag radials now. oh and I remember reading somewhere that the 3400 has a forged crank from the factory, just wondering if that was true, and if the connecting rods are also forged as well..

[Guest]

RE: Turbo size for 3400

Gt35R

[TurboZ24]

RE: Turbo size for 3400

Best place too ask is a good turbo rebuild shop, not someone like turbonetics, they typically suggest turbo's way too large with lots of lag.

As for the GT series turbo's, I really don't think they are worth all the extra cost (almost double a standard turbo), ball bearing turbo's can't be rebuilt in many cases, and are actually more susceptable too contamination in the oil than standard sleeve bearing turbo's. A good, T3/T4 hybrid turbo with a 360 degree thrust bearing from a good shop would be fine. The GT turbo's spool a little faster, but not much.

[SHOoff]

To properly choose a turbo, you're gonna need to know more than just the size of the engine.

[Doubt_Incarnate]

like your maximun capable RPM, the VE of the motor, your boost goal, or target horsepower all makes a difference, as do when you want boost to come in.

[feavs]

How do you calculate the VE? Whenever I did calculations, I just assumed around 85%, or something like that. What is the proper way to determine that number?



feavs

https://www.feavs.com

[TurboZ24]

You also need too mention some other things. They will ask...

Displacement
Max RPM
Intended HP
Intended Boost
Tranny (manual or auto)
Intercooled or non-intercooled

Technically you can map out the expected output, but without a dyno or a known VE for your specific setup, it's hard too say. Unless it's got a custom cam, head work and a few other goodies, I'd guess 70-80% for a stock pushrod motor. They can go a lot higher than that, but you need really well flowing heads, intake, exhaust, and a nice cam profile.

[Doubt_Incarnate]

don't you compare the air a motor can theoreticly pump (3.4l in this case) by what it actually pumps, to get the VE? always assume the worst. whatever number gives you the lowest power estimate will most likely be closest to the actual outcome. for a 15psi (2.02 PR) 3400 with a best VE of 80% at 6000rpm youd need like 600cfm from the turbo. the way i'd go would be to use the ever popular t3 that is everywhere like a disease. i'd snag a couple of good ones for a late xr4ti or the last years svo turbo coupes or the turbo mustang (all had the 2.3 turbo ford) from a local yard and shmooze ebay for the smallest AR turbine housings (.48 i think) and go with a twin setup. otherwise a single turbo that size would be like 1200 bucks. Its most likely not the best course of action, but it is a cheap starting point. Maybe the twin turbo 3000gt's would be a good setup to look at, the more efficent yet smaller dohc v6's might flow the same as the ohv 3400 and could provide a good starting point.

notice how i try to cover my own ass by using words that do not state exactness or claim the best. but flame away.

[matt_p]

I've come to the conclusion that the GT35R is a great turbo for what I want out of my turbo 3400 setup. But yes, they are damn pricey.

[3400beretta]

well we know displacement, max rpm would be 6000-6500 range, I stated I want to run as close to 20 pounds of boost as I can, I said I have a manual car, and really if your not going to intercool it, then its pretty much a waste of time, so I thought that was a given.. I have done some mild headwork and intake work, I plan on getting a cam, just not too sure on that yet, as I hear some things like the lsa should be changed for boost. Im shooting for the 400+hp range, and I really dont think thats out of the question. I have been doing more reading, and I am starting to understand compressor maps now, and I agree, the GT35R would be near perfect for this application, but is much too pricey, so I've been looking for a t3/t4 that is close to it. I think a t4 57 trim compressor mated with a t3 70 trim with a/r of .84 would be pretty good.. any thoughts?

[bszopi]

I just don't see you doing 20 pounds of boost. Curtis (www.turboz24.com) has been messing with his for at least 4 years (probably more) and his engine is capable of 20+, yet he hasn't turned it up much past 12 IIRC because either too many things break or traction is just non-existant. I'm sure he will chime in about it since he already has about turbo sizing.

[SHOoff]

Blah.......

How bouts a T04B S-Trim.

[Doubt_Incarnate]

i looked into a turbo for 12psi once, the only one i was happy with was the same one turboz24 is using. the 62-1 i think, or the 60-1. but at 1200 for a turbo plus engiine managment and fabricating stuff i scraped the boost idea for now.

[Guest]

Journal bearign turbos you can get for under $700 almost anywhere now

if you dont' want a GT series which are pricey, then go with a Full-race T3/61 turbo. Its a journal bearing turbo but has the gt series 35 wheel in it. Cost is like $750 Thats what you want.

it will support all the power you will ever want and spool quick too. I would go with the .82 exh a/r since you plan on running a high amount of boost. The 3400 will spool the .63 super fast. the .82 or so will spool about 300 rpm later.