z28mccrory

iTrader: (7)

Just curious if a 5.3 would be a better match to these small turbos that come with the Incon kit.

I have access to a 5.3, and have considered going that route instead of using the LS1.

Im fairly new to the FI world... but it seems bigger isn't always better. I see a lot a guy doing 366-370ci combos vs going with 408's... and that within reason any turbo will make MORE power on a smaller displacement motor, all else being equal.

I just want to get the most out of this kit, and it seems like most agree that these kits were never designed to go on motors any larger than stock CI due to how much back pressure it would create. Would a smaller that stock CI motor make more power on these somewhat small turbos.

Im not looking to set the world on fire with this setup, i just want a really nicely done street car that is fun to drive. Harlan made ~700rwhp with the exact same turbos and kit that i have. Others have sent the turbos off and upgraded the CHRA's, and made well over 800. I believe they flow 54lbs one upgraded... so should be able to make 1080 at the cank in theory. On a 5.3 mated with a 6-speed im wondering if i could get over the 900rwhp mark.

My other car currently has a really nice set of TEA 5.3 heads that i have considered replacing and using them instead on my Trans Am. They flowed 33X@.600 on TEA's bench and flowed 328@600 on Bischofs bench. I think they would work great on the 5.3 turbo motor.

Basicly the motor combo i have in mind:
5.3 Iron Truck Block
Stock Crank
Eagle Rods
Diamond Dished Pistons (whatever CC necessary to achieve about 9:1)

TEA 5.3 Heads
Turbo Friendly Cam
Vic Jr Intake (already have it and was port matched to 5.3's i plan on using).

I dont know if the power levels im going to be at would have issues with pushing water, but perhaps the more rigid 5.3 iron block would help with that.

One could say "well why not sell the Incon Kit and doing a big single" then say "well might as well go 370" ... etc etc and it never stops (thats what happened to my camaro). I love how reliable the cast manifold twin kits are, and would really like to stick with that setup. I want this car to be extremely street friendly, and everything i do to it keep that in mind. It was purchased to be my daily driver because i had taken my camaro too far.

$ho_tyme

iTrader: (3)

HAHA I love it,you as bad as me when you have buy another cause you taken it to far. I say just keep with the 5.7 as there not a huge differance in size. Those 28's are small, dont know anyway you can measure pressure in the exhaust to see if there choking it back. Bump for a fellow Hoosier.

engineermike

We could fool around and plot the data on the compressor maps to see where it winds up in either case, but I honestly don't think it will make much difference since we're only talking about 11 cid difference per turbo (162 cid vs. 173). I'm sure the compressor is more efficient, but probably not by much in the grand scheme of things. The GT2871 seems to be most at home on the 100-110 cid civics anyway. Even the imports in the 130-140 cid range go with the larger GT30's. My jet ski is only 90 cid and I'm running a GT32 on it.

Also, note that you can upgrade the GT2871's to GT2876's, which will support more power. Then there is the GT3076-WG, which has a T28 flange and will go even higher.

How much power NA would the 5.3 and 5.7's make?

What are your goals, anyway? Are you limiting the boost?

Mike

z28mccrory

iTrader: (7)

Honestly i dont know enough yet to know how to plot both on the compressor maps.

Its going to cost the same regarless of which direction i go. My uncle owns a salvage yard so i have access to a lot of 5.3's if i want them.

It seems like i have always been someone who constantly wants to go bigger better etc. On my camaro i wouldn't always pick the mods that were best for my current combo, but mods that would support me going much bigger down the road. I would always buy the "biggest" i could with plans to eventually grow into it.

On this setup i have a more definied "end goal". It will always have this Incon kit, at least that much in concrete. So now i just want to build a motor that will sufficiently handle this kit maxed out... be that the current turbos at ~700rwhp or some variation of them slightly upgraded to support more. Im not trying to make the car as fast as i possibly can with as much money as i can afford to put into it... just want a nice well rounded combo based off the Incon kit.

Im not chasing a certain ET or anything else... i just want it to be a fast streetable car.

engineermike

I understand that, but your boost limitation will determine what cid you need. For instance, if you want max power at 14 psi, it may be best to go 5.7 or bigger. But, if you want max power with the turbo's max'd out (22+ psi), then the 5.3 or even 4.8 could be best.

cablebandit

iTrader: (37)

5.3 would prolly be better on the smaller incons

black98ws6ta

iTrader: (77)

Agreed with above, if at any point you are going to max the kit out, the smaller motor will make more power. If your goals are short of maxxing it out the larger motor will spool better, and make more torque.

Rick_Vor

iTrader: (36)

Since the T28's are the limiting factor, would there be any advantage to building a forged 10.5:1 5.7? The extra compression would build a bigger base for the turbo's to build on.
Tuning would have to be spot on but the around town driveability would also be better.

Rick

sultan(ZR-1)KSA

with GT28s i maxed them out at 662WHP with a 347VI and thye very much died at about 5800 to 6000RPM so it all depinds on the target that you have and the way you use the car
I hope this helps