Petevb

I'm considering replacing my '06 cup engine to increase power and save weight. I believe none of the motorsports RS/ RSR motors are very suitable for me as delivered, as I'm looking for longer time between rebuilds and a more flexible powerband than those motors are know for.

Thus I think I'm looking for a special built with a mix of motorsports and perhaps street parts. If you guys were looking to get such a project done, who would you talk to? Any recommendations or usual suspects?

TIA

claykos

I went through this and it gets complicated...a big hurtle is the ECU. PMNA has a pretty good lock out on the mapping of the Bosch ECU, so if you want to do something custom you are going to need to go with Motec.

I was going to do something custom with hydraulic valvetrain and individual throttle bodies, but after a looong process ended up basically building a 2004 RSR spec 3-ring piston motor. In a club race environment it should be about 50 hours between refreshes. The main issue with the lifespan is the solid lifter valvetrain which needs maintenance.

It is complicated to figure out what parts are compatible with what. There are different rod lengths that work with different pistons, different cams that need different cam boxes, etc etc. If I was going to go for the best balance of lifespan/power and money was no object it's hard to beat the new 3.8 cup motors...if you wanted to get wild you could put throttle bodies and a carbon plenum on it which would probably bump the power a bit.

jrgordonsenior

I would recommend Loren Beggs of 911 Design in So Cal. He's been building 4.0 liter cup motors that dyno around 450rwhp and haven't had any issues to date...
www.nine11design.com

coryf

Send Gordon at autometrics an email. Gordon@autometricsmotorsports.com He should be able to build exactly what you are looking for.

Mark GT3

Jeff Gamroth @ Rothsport
503-885-9626
rothsport@frontier.com

My RS is about to undergo a 4.0L conversion with individual throttle bodies. I'm sure Jeff could build an engine that delivers what you are after and more.

pranqster

Kent Moore
Premier Sportscar Service
4005 West Dewey Drive
Las Vegas, Nevada 89118

Shop Hours: M-F 9-6:00
(702) 649-8267

mklaskin

Not to complicate matters, but I just had my Cup motor rebuilt to a 3.8 liter from a World Challenge spec 3.6. Jim Labine at PMNA said the engine dynoed at 470...

Tough to beat.

jrgordonsenior

For clarification, that would be flywheel HP on their engine dyno. RWHP assuming a 10-12% loss would then be somewhere between 415-425....

jrgordonsenior

I think you should contact all the fine shops recommended here and ask them to prepare a written estimate based on what you're looking for and the condition of your motor. It would be really interesting to see what shops recommend and their respective costs.....

mklaskin

Correct.

Were you saying that Loren's builds have that much power at the wheels?

fapena

Another vote for Autometrics. They have built impeccable engines for me in the past for my 996, and recently I had a chance to check a build by them, 3.8 engine in a 997 at Road Atlanta, and that thing was almost pulling away from my 2011 Cup car. VERY impressive!!

Gordon is not only an experienced engine builder, he will also stand by his word and work (and that part I know it first hand). You can't go wrong with him.

Just my 2 cents.

Thanks

FAP

mooty

LOL, "written estimate"....
you MUST have heard of "change orders" in your line of work

jrgordonsenior

Yep. His 2 recent 4.0's both dyno'd over 450 rwhp.....

gmgracing

There are a ton of options and configurations with the 4.0 liter platform.
Are you looking to do a proper 4.0 liter as a stroker engine or are you going the way of doing pistons and cylinders only.

Do you want a sprint engine or an endurance engine?

There are options for ECU tune as well and we can help with that from Motec to Bosch Motorsport to a custom tune if needed.

We have a complete and proper test cell where we dyno all our cars and can provide engine dyno data as well so you can compare and get an accurate number of the real power the engine makes.

Feel free to drop me an email and I would be happy to advise of options.

Jeff951NJ

You may want to give Peter or Trevor a call at Dawes Motorsports. Sure see alot of his Cup cars up front at PCA races.

http://www.dawesmotorsports.com