Horsepower quiz

[ozz]

Just for a little fun and for the engine builders out there and the arm-chair engine builders, I wanted to get your feedback on what you think this engine configuration ought to dyno out at - RWHP, SAE corrected numbers of course. If you have a number other than in the poll feel free to post it seperatly. Providing Torque numbers gets you extra credit on the quiz.

Here are the major pieces of interest:

78 3.0
10.5:1 Compression
Rods shot peened and balanced w/ ARP rod bolts
ARP Head studs
boat tailed case
GE60 Cams
Port and Polish heads
Port and Polish manifolds
Stainless Steel valves
46 mm PMO carburetors
Crank-Fire XDi Electronic Ignition - twin-plug

Fully broken in, fresh valve adjustment, running 94 Octane Sunoco pump gas.

Have at it and remeber, this is just for fun....

[jmz]

very simlar to my engine. Except I have weber 40s (36 venturi) did not boat-tail the case and am running 9.3:1. For a reference I dynoed at 212 at the wheels. The c2 on the dyno right before me pulled 240 for a reference point.

[RLJ]

My motor was/is a short stroke twin plug 3.2, 10.25:1 CR, 3.2 Carrera heads, with SSI's, dual in dual out muffler, cams close to yours, and 46mm PMO's. She made 223 HP at the rear wheels.

I have removed the carbs, SSI's adding EFI and a set of Georges 1 5/8" headers. She now makes 298 HP at the crank. When I get her up and running we will need to go on the Dyno Jet and work off any ruff edges and then I will have an answer for RWHP.

Randy Jones
1971 911 "Iris"

[kenikh]

That config should get you close to 300 at the crank if it will spin high enough. With a correction factor of .8, that drops it right into 235.5 HP at the wheels.

[1fastredsc]

What port size are you running, and does the intake match that size?

[ozz]

Randy - what casued you to go away from the PMO's? Particular issue, overall performace??

Kenik - 225-235 at the wheels was what I had targeted - rev limiter is set at 6800

Fastred - I'm embarassed to say I'm not positive on the port size but I want to say 36mm and the "tall boy" manifolds were to be matched.

[kenikh]

It seems to me that you are choking the GE60s with a redline that low. GE60s like to REEEEEEEEEEEEVVVVVVVVV...

[ozz]

Kenik -

That might be so, it looks like the engine is coming on cam around 3800 or so and I have a fairly flat (usable) power and torque curve to redline. Based on the A/F info, I'm thinking it is a little lean over 4000 so, I have some more reaserch and jetting work (or at least experimenting) to do. I'm going to send the info to Mr. Parr and see what he can tell me on that front.

[Tyson Schmidt]

I doubt that your ports are 36mm. Shops don't usually make ports smaller when they port them.

An early 3.0 is 38, IIRC.

Yours are probably 40mm now?


I'm guessing 215 RWHP.

[ozz]

Thanks Tyson - we put this engine together in 04 and, I was pulling from vague (obviously very vague ) memory.

The disappointing news is --- we pulled 4 runs. 2 at 193rwhp and 186 ftlbs torque (give or take a few 10ths) and 2 and 195 rwhp 189 ftlbs torque The A/F looks a little lean over about 3500 rpm (13.4's - 13.5s') and, I need to get a timing light on it and verify the XDi timing map.

My target was 225 to 235. There has to be more in there, I just need to find it and, keep some sense of street drivability there.

[Bobboloo]

Stock 78' ports are 39mm I / 35mm E.

I'm guessing 217.

[Early_S_Man]

Redline -- 7300 rpm without special crank grinding work, i.e., large radius filets and special bearings!!!

HP = 230

[jmz]

You should have at least 20 more H.P. than I do based on your build sheet. Once again I pulled 212 h.p. and am a full point lower in C.R. and did not boat tail the case and am running 40s. IF your dyno is accurate then you've got some more in there.