Mark02z28

Hey guys I'm new to a boost application so sorry for the stupid questions but I'm doing a turbo build on my 02 z28 it's currently a 6.0 lq4 car I'm swapping in a 4l80e as well I have ported 317 heads and a ls6 intake manifold I'm curious on some advice from guys that have ran thr on3 76mm and on3 78mm I am wanting at least 600whp but closer to 700 would be nice lol just curious if the 76 would take me there or if I should use the 78mm I'm also thinking of using the speed inc tu2 cam so any advice would be appreciated

Mongoose350

iTrader: (1)

Between those two, the 78. The 76 has a 65mm (I think) turbine and that's pretty damn small for a 6.0. The 78 has a 75mm turbine, still on the small side but much better. Should make 650-700 no problem. Don't expect much more though with that small turbine. If you can afford it, get a S47x turbo. Huron has great deals on them.

IronBlocked

For 400 bucks don't you wanna go the extra mile and spend 650 on a borg warner? Much better turbo and turbine wheels suited to your big displacement engine

RedRocketZ28

iTrader: (19)

There's my old car with a similar setup to which you described. I ran that turbo in the 18 psi range on the street a few times but it didn't feel like it gained much power over the 14 psi on the dyno. Power dropped off hard after 5500 rpm as well. Definitely was fun to drive around on the street. Made the switch to a Turbonetics 7875 and made just shy of 700 rwhp on 16 lbs. If all you are looking for is around 6-700 rwhp, then either one of those turbos you mentioned would work. I would look at getting a different cam than the TU2 though. I had the TU1 and it worked well, but a turbo cam tailored to the small exhaust wheels would be benficial and help pull a little higher in the upper RPM range.

Mark02z28

Thanks guys I was planning on upgrading the turbo after a short time just figured one of the on3s would be a good starting point to getting use to a boosted car since my car was a h/c/I last season but I might just spend the extra money and get a better turbo redrocketz28 you think the tu2 cam would be too much if I used a better turbo or would it just be better to use the tu1 or a different boost cam I just want to kind of keep the aggressive idle but still make good power

Rise of the Phoenix

iTrader: (27)

Correct me if I'm wrong, but if you go with an On3 76 or 78, you won't be able to just bolt up a Borg turbo and go without making modifications to the down pipe.

Mark02z28

Your probably right I was planning on ordering the cx racing hotside which is a t4 flange I think u can get a s475 as a t4 but I'm not entirely sure

Mark02z28

My main reason for making this thread is I already have a on3 76 laying around new in the box but wasn't sure if I should just throw that on or sell it before I get really into this build so far I'm finishing up the motor got my heads back about to pull my old cam for whatever my new one will be I have a 24x12x4 intercooler already mounted and I got the hotside ready to order just holding off til I do more research

Rise of the Phoenix

iTrader: (27)

Yes, you can get a S400-75 in a T4 flange. Since you already have the On3 turbo, I'd just roll with it and see how it does. In all honesty, it will probably be more than enough for a street terror/weekend warrior. More power is great, but it's a waste unless you can hook it on the street.

Mark02z28

Hopefully I can get it to hook pretty well with the 15x10 racestars in the back with a good sized radial

IronBlocked

Yeah keep the on3, nice car!