66mm x 98mm Turbo Engine Build

[Mike Billings]

Wanted to share the details on a 3.0L engine that Supertec built for me. Maybe there's a couple items in this build the community will find inspiring.

I asked Henry if we could build a turbo engine that had an RPM limit like the GT cars, but would go a little longer between rebuilds. My 1973 (DE) car weighs 1850 pounds dry, so big displacement or torque was not required. So yes, the higher RPM limit was just for good noises and fun. I would transplant over all of the ITB turbo plumbing from my 2.8L. That engine pulls hard to 8000 RPM on every shift, so I felt we would not be choking the engine with that setup moved over to the new 3.0L.

Every idea I had how to build this engine, Henry completely topped it. I thought we would de-stroke an SC crankshaft, but that would be too weak. I really appreciate Henry's thinking on this one.

I felt the engine would be more serviceable if the bore was kept to 98mm and no larger. Also I wanted to be sure we did not under-cam the engine. Has to pull hard to the RPM limit.

An '83 non-sump plate core engine was found for this project. Some earlier small port heads were sourced so the port work could be done. Here's some of the hardware and machine work:

Dougherty Racing billet cams
66mm Supertec Supercrank
GT3 rods
GT3 main and rod bearings, dry film
GT3R oil pump
shuffle pin, boat tail, Supertec head studs
98mm Mahle cylinders
8:1 JE FSR pistons
39mm ports I/E, twin plug
993 valves, 8mm and 9mm stems, AMCO 45 exhaust seats
Supertec valve springs, titanium retainers
forged rockers
I think stock layshaft with COMP chains and ramps
Supertec tensioner arms and tensioner fail-safes
lightweight steel flywheel

Cams are custom, but around DC43 in specs. The DC43 is spec'd for 800+ WHP turbo engines, so I like how John thinks!

Henry felt the next step for this engine would be Xtreme heads, but that would pop the budget.

I use a solid-center 4 puck disk with Sachs sport PP + 915 trans BTW. Works just fine for this car. May have to make a change there soon.

Turbos are twin T03/T04E hybrids. Plenty! My 2.8 L loves them!

Sadly, this engine has been on an engine stand for over a year. I did fab and tack weld some 321 stainless headers on it. They have flat collectors because I like the look of those. Primaries are 1-5/8, 2.5" collectors, same size as on my 2.8L.

I also shortened a GT3 intake to mount on the enlarged 911E throttles for this engine. Intake is not tack-welded yet.

Problem is I got bogged down working on another car. Also the 2.8L is still running strong. Don't need to pull this 3.0L into service yet.

Hope you all enjoy the details and Henry's photos.

I don't want to give away anything that Supertec considers proprietary. Please let me know if I cross a line.

[Mike Billings]

[mikedsilva]

wow

[faapgar]

Great specs on this build.Should rev very quickly.Henry does great work.Please finish soon and post results.Fred

[MST0118]

This is a great build!

I have read on other threads that simple case mods are recommended for oiling when using the Supercrank. Do you happen to know what those case mods might be and who did the machining for your case?

[Mike Billings]

Supertec prepped the case but I don't know what they did.

There's a a very active thread on this board right now that has some excellent details how to mod the case for better oiling.

[Trackrash]

Holy moly. I would love to see a post of this motor running at some point. Thanks for sharing.