Planning turbo engine build
 

I have some 32cc dish pistons in a 4.25 bore diameter that I want to use. I am planning on using these pistons. My thought is on what crank I would like to use. Should I use the offering from Molnar in a 4” stroke or should the 4.25” stroke. This is not some max effort engine, but should run good.

I have my 74cc combustion chamber aluminum Kre Dports for cylinder heads. With the 4” stroke I will get 454 cubic inches at about 9.04:1 compression. With the 4.25” stroke I will have 482 CI at about 9.54:1 compression. I have the turbo manifold already set up for a single turbo. I am thinking of using s S400 or an S480.

This is not a total budget build, but I do need to spend my money wisely to get it done.

I'd go with the 4-in stroke. either stroke it'll be a really cool build. Good luck

What's the CH of the pistons?

Travis Quillen told me some years ago, that he should have gone with a 4" stroke vs a 4.25 stroke
(482 cid in their 4.25 stroke Twin Turbo engine).

Tom V.

I’m currently gathering parts for my twin turbo build. After long discussions with very smart people who have been there and done that, I will be going with a 4” stroke. The extra load on the cylinder walls with a 4.25” stroke is not worth it. Don’t worry about the cubic inches, let the turbos make the power.

For a turbo recommendation try https://www.forcedperformance.shop/ and ask for Robert

This is a good video regarding journal bearings and ball bearing turbos

https://youtu.be/zEVEAnRdEF4

Thank you so much guys. I really appreciate your feedback about Travis Tom. He is an extremely smart guy. I will jump on Johnny’s amok at buy and hope we can get a deal going.

I will have to check AG. I bought them years ago and they are in my storage unit.

Thank you Charlie. I need to try and move this build forward.

Thank you for the videos R 70 Judge. I appreciate your feedback.

Smart enough that he is a "ROCKET MAN" for NASA these days vs a Pontiac Hot Rodder.

Tom V.

Keep us posted. I hope you figure it out to your liking . Sounds like you have most of the stuff . Even if you used a 3.75 stroke it be killer...

Im using a 3.75 in the motor im building now .. I have no doubt it will have more power/torque then ill ever need..

Thank you Charlie. I have collected a few parts over the years. I just need the crank, aftermarket block, crank, turbo and figure out an induction system.

I’m using a Northwind with a Steve Morris billet elbow and a Wilson’s 105mm throttle body with Holley Terminator X EFI. I have thread going in the EFI tech section if you want to duplicate anything.

I recommend you get the ring lands hard coated/ Anodized -- It will really help in the long run.

Curt is there someone local to us to do the anodizing or do the pistons need shipped off?

A few people asked to see my turbo manifolds that I bought a few years ago. I finally was able to make it out to my storage unit to get some pictures. Here they are if you all have any more questions let me know.

Hope they PACKAGE as good as they look in your vehicle.

Have fun. Tom V.

If this is a factory block are you planing to fill it up to the bottom of the front timing cover water passages.

I have mocked them up in my car and the turbo will sit real close to where the battery used to be in my Firebird. I will weld up a support to help support the turbo on the passenger front frame rail. I have been trying to do this build for a while. I start to get frustrated and think I will just sell everything. I just keep telling myself that the parts aren’t costing me anything sitting there. Thank you for your insight Tom.

Hey Steve the plan is to get an aftermarket block. I figure that would be the best way to go since I already have the dished pistons for a 4.25 bore.