3.2 SS: finally got it on a dyno

[ohecht]

It's been a long project, and rebuilding the transmission, suspension and brakes all at the same time was probably not the best plan, but I finally got the engine tune refined on a dyno.

The most amazing part was the car ran nonstop on the dyno at part and full throttle for 3 hours straight and never went above 180 degrees...with one small fan on the front oil cooler and two larger fans pointing into the engine compartment...that part amazed me!

Here's the dyno sheet, specs, and a link to some videos...235 hp at the wheels and 200 ft/lbs with a nice, flat torque curve between 4500 and 6200. The sound as the cam comes on is addicting and I'm trying not to get into trouble with the car now! Track time is next, but the build goal was a streetable car with occasional DE time as it's also my daily driver (and mountain bike hauler!) I'm pretty happy with the results...the car is a blast to drive! I'm amazed all the parts I bolted together are still together when I hear it rev like this!

Special thanks to many from these forums who helped along the way, and especially to Henry Schmidt and Jamie Novak for their generous advice!



Specs:

'82 SC (3.0 case and crank)
98mm JE 10.5:1 coated pistons
98mm cylinders (Mahle?)
~RSR spec valves, and CNC headwork by Xtreme
Raceware rod bolts, balanced stock rods
Supertec studs and cryo-treated rockers
Cross-drilled crank
Twin plugged
993 SS cams
B&B 1 5/8" exhaust
Carrera intake...extrude honed with oversize TB
ID725 injectors
Sequential ignition (Clewett cam sensor)
Dual Ford EDIS ignition
Megasquirt 3/MSX ECU
All new (and finned) ER oil lines

[IXjamesXI]

Whoa!!! Awesome. Inspirational. And its your 911th post. How was tuning with the 993ss cams? I am doing a very similar 3.2 ss with those cams. Kudos!!!!!!!!!!!

[ohecht]

Thanks, and that is hilarious about the 911th post...I wish I could claim I planned it that way!

This is my first rebuild and tune of an entirely new motor setup, so I can't really say anything either way about the 993 cams from an ease of tuning perspective. I know that the first WOT run on the dyno was about 235 hp, and there wasn't much the tuner could do to change that despite trying several things, so I guess you could say it's "tolerant" or "stable" relative to fuel and timing. He spent a lot of time smoothing out the torque curve as much as possible. I think you can also see the intake reversion at lower RPMs, but I think that's the nature of the cam and part of what I wanted in an engine with more of a broad and usable torque curve over peak power.

I think this motor could make much more peak power with smaller intake ports and valves, larger primaries, and a more radical cam, but it feels great like this. The biggest problem is me constantly driving in a low gear so I can rev it to 6-7k with the windows down and a huge smile on my face just listening to it...I need to be careful and get on a track more often!

I can also recommend the ID725 injectors even though they are way oversized for this engine on paper (and crazy-expensive...I'm saying they are effective but not cost-effective!). I got all the deadtime and small pulsewidth information from Injector Dynamics with them, and they are very tame at idle despite being capable of flowing so much fuel. Just in case someone needs a streetable idle and massive quantities of fuel elsewhere for some reason...still overkill for my application, though...I certainly could never overheat them with this engine! Probably the most impressive outcome of the tuning session was that the car now idles just like any modern car.

[IXjamesXI]

235 is plenty impressive at the wheels. That puts you over 260 at the flywheel.. Depending what kind of driveline loss factor you want to use. Not sure what the consensus is on that one.

Did you go alpha-n or map or some combination of the two? Nice to hear it behaves at low revs.

[ohecht]

I'm using MAP and Speed Density.