2276cc Turbo selection

[thedrew]

Hey smart turbo people -

My engine is currently NA, and I think i'm ready for the next step.

-2276cc - ACN's SSP pistons
-5.400 h beam rods
-Steve Tims Stage 2 heads, 58cc
-40mm EFI throttlebodies with 32lb injectors
-MS3X with LS2 coils

I'm planning on running the 86B cam with a DH of .070 which will put me at 9:1cr.

Target boost pressure is maybe 10-12psi?

I want to use CB's hideaway exhaust, so picking a turbo is knocked down to Schwitzer S2A or Airesearch TO3.

But what size?

From what I understand, I'd want a smaller A/R on the turbo so it spools quickly and with that cam I'm not going to be wringing it out past 6500-7000rpm.

I imagine I'll have to upgrade my injectors to maybe 500cc's or so.

School me! Go!

[blue thunder]

What valve sizes are you running in those heads? You will probably easily run up to around 7500 rpm with your combo (depending on the inlet valve size), since you have probably retarded the cam 4 degrees for the SS pistons.
With the SS pistons and relatively higher CR you can run with this combo, I would suggest not to go to small on the
T3 turbine throat area (or AR ratio). A .82 or even a tad larger would still spool up great, and will not restrict the engine at higher rpm (thus keeping the tempertures in check). I would recommend a T3/T4 hybrid (T3 turbine, T4 compressor or if you would prefer a ballbearing, something like a GT28R or a GT30R) as this size of engine can benifit from the extra flow from the compressor. I have quite a similar setup (2276cc,SE heads 44x38, SS pistons and similar custom cam, E85 fuel, 1000cc ID injectors) and I will be running a Precision GT3076R with .82 AR turbine. According to Engine Analyser Pro, I should reach max torque at 3000 rpm and max power around 7000 rpm.
Of course you could run a smaller turbo, but I think it would not be the best combo for your setup. Just remember to relocate your wastegate to after the collector, as the stock CB hideaway location is terrible (on one cilinder).

If you plan on running above mentioned turbo's, you probably need larger injectors than 500cc on gasoline. With E85, 500cc will be way to small....

Good luck,

Robin

[Chip Birks]

2276
SS Pistons
.06 deck
9.1:1
44x37.5 heads by Shag
Shag cam has 264°@.05 and .570 lift at the valve. I run it straight up. Big chambers keep my valves from smacking pistons.
Shag T3/to4e .63ar
A/W Intercooler
I use Injector Dynamics 1000cc injectors with a big Walbro twin screw pump feeding them, so far it is keeping up. My old Walbro 255 couldn't keep up with the IDs on e85(100%DC@14:1 A/F). The car runs on gas or e85. It's seen 24.4psi on 91 octane, and 28psi on e85.

7500rpm is not a problem for it at all. You need to remember, even though power will taper off as rpm gets real high, the motor is still making TONS more power than it ever did while aspirated. You won't notice the plateau for a while

[thedrew]

heads are 42x37.

I'm leaning toward the .63ar like Chip has.

I'm having trouble finding 1000cc injectors that will fit where mine are (current ones are 38mm oring to oring), the best I can find is 880cc. I'm now sure if I'll mess with E85....but I'd sure like to have the option

[Chip Birks]

Are your manifolds a one off part or something? That is super short.

[thedrew]

i have the injectors in cb's manifold, and the injector rails are damn close to the engine bay walls (i had to use a hammer to get a bit more clearance when I first put them in)

I'm using these injectors (compact size)
https://www.fiveomotorsport.com/233usx- ... -injectors

[thedrew]

I found some 1000cc injectors, I just ordered em, so I guess I'm commited!

now to finding a turbo -- I'm still thinking .63ar. CB sells the AGP one for like $650, I hope I can do better than that price wise.

[Chip Birks]

That price sounds pretty good to me. You could always contact Shag or Marty Staggs and see what they have to offer.

[bug66]

What's your power goal?

1000cc is JUST enough for 400whp on E85.

[thedrew]

shoot, I dont have crazy goals...I'd like to see maybe 220?

[bug66]

Then you are well in the clear..

[thedrew]

what transmissions are you guys running?

I have a Wright Gearbox pro street. I know side stepping the clutch is what kills em, but how will it do with booooooooooost

[petew]

There are guys over here running 300hp subarus behind stock standard late IRS boxes. The main issues with be how you treat it. Sounds like you've got the right specs there.

http://www.wrightgearbox.com/volkswagen

Be a little gentle and it should be fine.

[madmike]

X2 with Pete,I made 6 or 7 passes on a "Bone Stock" transmission W/slicks
and Don't overClutch it

[Clonebug]

I slipped the syncro hubs at around 120 hp with my carb turbo. Once you get around there and get some hard 3rd and 4th gear pulls you will find it doesn't want to shift very well anymore. That will be your first clue.....
I did it to two transmissions....my 67 and my 68. I had the 67 trans. rebuilt and the third and fourth gear hubs welded for $350.00. It needed a new main bearing, the hubs welded, a couple sycro's replaced and reverse gear replaced and readjusted.
It has been working flawlessly since then. which has been about 3 1/2 years now and a lot more power going through it.
No drop clutches but I do shift fast enough to break them loose going into second gear.