2.7 autocross engine

[Bill911]

Hello, I have a 2.7 S engine. I want to build it for the sole purpose to put in my 914 aytocross car. Does anyone know what kind of horse I can fet out of it ans what types of modifications. I can run carbs or programable Efi. I was thinking about a web cam (464/465), JE domed high compression pistons and a good build onthe heads. Can you increase stroke length on this engine? Or should i just buy a 3.2? I would appreciate suggestions.
Bill

[Walt Fricke]

Bill - time to do your homework. Buy our host Wayne Dempsey's book on rebuilding 911 motors. And Bruce Anderson's book on the 911 motor. Read what they have to say about modifying various models. Then decide what to do. I think you will find that information more valuable than hearing what various people have done for race (autocross is a form of racing) motors.

Among other questions these books will answer is stroking. There are two strokes you can run in this case - 66mm and 70.4. To go longer (assuming you don't have a special stroke ground just for you - $$$$) you need a later case.

I think you will find the general concensus is that the magnesium case is not the way to go. Worked OK for factory horsepower levels, leaving aside the problems with pulling head studs. But it is problematic when you start pumping up the CR. I have a 2.7 race motor which worked great, but it has an early sand cast case, turbo oil pump, straight cut IS gears, 2.7RSR pistons, an Elgin 315 cam, 46mm Webers, lightened flywheel and pressure plate, makes 220 rear wheel horsepower, and optimum upshift point is 7,600 rpm (though it will happily rev up to 8,000, maybe more, whithout feeling like it is running out of breath). About all that's left of my original 2.7 are the crank, rods (with high strength bolts), some of the cylinders, the heads (worked over some), cam carriers and chain boxes, valve covers, and miscellaneous other bits and pieces.

I'd be so bold as to suggest that you put carbs on the motor (to simplify the plumbing and conversion more than for any other reason), add a good exhaust, do what you need to put it into a 914, and go drive. I'd suspect it will be a while before you can legitimately say you are losing races because you don't have enough power.

Though for all I know, you are a past SCCA national champion, in which case I apologize.

[GeorgeRud]

Henry at Supertech in Fallbrook, California can give you guidance, but to properly build the engine is $$$! That's why many folks like to start with an aluminum block engine, thought he costs are also very high to do it properly.

On the other hand, a prepped 2.7 will give a lot of grunt in a 914-6.

[burtm5]

I'm thinking 2.7 with 9.5 cr JEs. 40 webers, ssi, early muff, 35 mm stock heads, E cams, stock rods, will turn 7000 at 210 to 220hp at crank.

[Cupcar]

Originally Posted by Walt Fricke

...I'd be so bold as to suggest that you put carbs on the motor (to simplify the plumbing and conversion more than for any other reason), add a good exhaust, do what you need to put it into a 914, and go drive. I'd suspect it will be a while before you can legitimately say you are losing races because you don't have enough power.

Though for all I know, you are a past SCCA national champion, in which case I apologize.

Above is Good advice IMHO, otherwise the best way to horsepower for autocross is displacement increase on an aluminum crankcase all the way up to 3.6 liters if you can.

Displacement liters are cheap horsepower compared to horsepower per liter which comes at a more dear price.

[larrym]

depends a whole lot on what AX Class you plan to run in

if you plan to buy your gas 5-gals at a time at $10/gal or expect to run pump gas

and on how may seasons you want the engine to last before you have to redo it again

E cams are great for low end torque - i found they run out of steam around 5800. but good AX choice

.

[Bill911]

I am not worried about class as much as i want to go hone and say i had an FTD!! The fast cars in my area are a 914-6 gt 3.2, 2006 corvette, a 2004 gt3, and a 1973 911, 2.4.

[Walt Fricke]

You won't get FTD in an autocross on power alone.

[Cupcar]

I got FTD's with a 914/6 using a 2.7 with RS pistons and cylinders, S cams, Webers, headers and S size ports.