View Full Version : SC motor swap done, progress update

06-29-2007, 06:47 PM
I dropped the car off last week to LaSota RAcing in Hilliard, Ohio before going out of town. They did a dyno tune on it since I am using the existing 95 LX 3.8 PCM with the 90 SC engine. A little background, the engine, AOD, and driveline all the way back to the rear spindles and wheels came off a rusted out 90 SC. I tore the motor down to shortblock level, resealed it and did some hand porting and gasket-matching on the heads and intake. Also has a custom true-dual exhaust and K&N FIPK. It made 187 RWHP on a Mustang Dyno. Not bad IMHO since I didn't replace any bearings, or even valve seats or seals. The motor has 165k on the clock. I won't be back to get it for another day or two, but based on my past experience with these guys I can't wait to get it out and drive it.

07-01-2007, 07:09 PM
By the way, what are some dyno numbers for a stock SC? I thought I had heard 145-150. Reason being, I picked up the car and drove it home, and it doesn't feel right. It should be much quicker if only from the dual exhaust and 250 lbs less than the other body it was in. Trying to figure out if it's all in my head.

07-01-2007, 08:46 PM
145?? really??? i heard 185-190:confused:

07-01-2007, 11:33 PM
about 190 sounds right at the wheels

07-01-2007, 11:41 PM
5-speeds should make around 175rwhp autos should make about 160rwhp.

It sucks when you get all hyped up about getting your car back and you over think how much faster you think it will be isn't it?

07-01-2007, 11:46 PM
Yeah, especially since it SHOULD BE faster. With a dual exhaust and lighter body there is no way it should be slower than it was before the swap. I'm gonna run a few tests on it before I go have a chat with the guy who tunes it. Leakdown, different PCM...

07-02-2007, 09:54 AM
To get near 190, you will need to free up some ponies with a K&N panel filter and a 5% overdrive on the blower.

That put me at 189 on a hot day in MN on my previous 1989 car. That was with old plugs and a tired motor.

07-03-2007, 12:40 AM
It was dynoed on a Mustang dyno, so the numbers will be a little lower. I spent some more time in it and it isn't as bad as I thought, especially since he put three tunes in it and I found the good one later on. It stumbles right off the line, but I don't think anything can be done about that since the AOD wanted to shift if they went under 3000 RPM. It actually acts like the powerband moved upward 500-1000 RPM, more acceleration once it gets going. I'm thinking that might have something to do with my porting work (I gasket matched the intake and heads, unshrouded the valves, did some cleanup on the short-turns in the runners, and opened up the collectors in the exhaust manifolds).

07-03-2007, 09:42 AM
145 is probably fair on a Mustang.

Really the only way to get meaningful numbers are to do before and after mods on the same dyno and then use corrected numbers understanding the difference air pressure and temp will have on the car.