355gta

I am building a turbo 355. I am going to use speed pro forged dished pistons, forged h-beam rods, forged cranks, motown block, afr 215cc heads, SCE titan copper head gaskets, accel 7th gen. DFI, ARP head and main studs. The bolck is going to be half filled. Also, the turbo is a precision PT91 and a 50mm wastegate with a 4" down pipe. The car will be completely streetable. I will be having about 8psi of boost for the street and maybe 20psi at the track. MSD 6BTM will control the timing and ignition. I know that is a big jump in boost but I will have a multistage electronic boost controller, maybe the Apexi with the built in wideband and 3 stage controller. I was wondering what everyone thought would be the best rings for this combo and if anyone sees anyway to make this combo work better, feel free to let me know. I have been researching for a long time and have built several turbo cars, just never a small block chevy. Thanks

trbo355

There are some things that dont jive in your post like half fill on a motown block? Why? It's already bulletproof! Do you have Gen7? If so, there is no need for the 6BTM since you already have timing control in the accel unit. It sounds like a recipe for one fast car for sure! As far as rings go i would use some plasma moly rings since they take a lot of abuse and seal up well on street motors.

Sonix

iTrader: (1)

That's a high buck motor right there.
Gapless seems like the only way to go.

355gta

I know you should not go gapless on a boosted motor because you can break the ring lands off of the pistons, even forged. I do have the 7th gen, but not the 6BTM. I know on the 7th gen you can run fuel control and do away with the timing. 6BTM's timing retard is superior to the accel as I have heard. Yes the blocks are pretty well bullet proof up to about 800hp. I am eventually shooting for 1200hp and I would rather be safe then sorry. If I am incorrect on the ignition, please let me know. Thanks

355gta

No takers. I thought with as much turbo guys on here they would be alot of input. I forgot to add that I will be running a vacuum pump. Probably the moroso 3 vane.

calebzman

iTrader: (3)

I agree with trbo355 as far as using the plasma-moly rings. Have you said what fuel system you're going to run?

TurboedTPI

I run speed pro moly rings. And i agree, i dont see the need for the half fill on the motown block. I got the stock two bolt L98 block and crank making close to 700hp at the crank. One other question, why only 8 lbs on the street?

355gta

The reason for half filling the block is because I only want to build the motor once and freshen it as needed. I eventually want some serious power out of it and I might as well have the machine shop do it while they are there. Also, I will be Accel 7th gen. DFI. I have been researching the programming part of it. I will be a challenge but I am up for. As for the 8psi on the street, I am not sure of the exact size of your 62-1 but I have a precision PT91 which is 91.5mm inducer and the volume of air will be much greater, so I will drop the boost to compensate.

askulte

If you're getting custom pistons made, have the ring land as thick as possible. It'll screw with emmissions, but having the top ring protected will help keep it from overheating. I'd pass on the block fill also, as I've never heard of anyone distorting that block. I built my Little M with the idea of a "forever" block. I had it hot honed to the minimum it would clean up (4.1215" bore), which will give plenty of room for freshening years from now (up to 4.185").

83 Crossfire TA

iTrader: (2)

Well, repeating a lot of things that have been said with some additional feedback…

I really doubt that you’d need to fill that Motown block, if in doubt ask them, but I think you’d be better off without it.

Gapless rings are generally a disaster for anything that you want to be long term durable (or anything that you want running higher RPM’s for longer periods), I’d go with andris’s recommendation on cutting the top ring groove down as far as you can comfortably get away with, run a quality set of normal gapped rings, and grind the gaps towards the outside of the recommended range. That way you end up with something that may have slightly more leak down then you would have with gapless rings or tight ring gaps (who cares, turn up the boost and you’ll never notice the hp or 2 you lost doing that), but at the same time it will be reliable and bullet proof if you overheat things or lean on things a bit hard you don’t have to worry about breaking things for many times longer then a less conservatively assembled setup.

I don’t have a clue why you’d run a BTM if you’re running a gen 7. For one thing, program the dfi for the timing curve that you want under boost and leave it. Second, I’ve been shocked to find how many BTM’s just stop working after a few years (as in the box still works but it’s no longer retarding the timing.

Sonix

iTrader: (1)

Well i'll be damned... And corrected.

Out of curiosity, what's the A/R on that turbo you're using?
91.5mm inducer sounds like a huge turbo. What cam is planned for this?

I just like to hear more about other peoples turbo car setups.

kmracer66

that turbo it too big to run on 8 psi and be happy. you would be much much better off with something like a 76mm turbo. thats just too much turbo for the street for your displacment. i couldnt even see a need for a 88mm turbo.

83 Crossfire TA

iTrader: (2)

Althogh I agree that turbo is probably too large, smaller turbos are usually happier pushing the same mass of air at a higher boost pressure then a larger one.

dennisbernal91z

iTrader: (2)

don't mind me, just subscribing.

askulte

At the top of the thread, there's a button "thread tools" with the option to subscribe.

Andris

Greasemonkey

To a thread that has been dead for a year? Not that I mind, as I found some good info in here.