As a project progresses, it tends to take on a life of its own. This is exactly what has happened with our '93 LX SSP. From its early days of 14-second e.t.'s, it's sure come a long way to its current 11-second status. Meant to be an everyday driver with enough gusto for slaying Brand-X muscle, our coupe has stood up proudly as an all-around performer.
In the Oct. '10 issue, we installed a Zex nitrous system on our resident SSP coupe. On the dyno, the 125-shot translated into an 86 rwhp and 84 lb-ft of torque gain. Certainly a nice increase, but the dyno graph revealed that the output flat-lined at 5,000 rpm. Looking to free up power a bit higher in the rpm range, we called up Edelbrock for one of its Performer RPM II intake manifolds.
Designed with larger and shorter runners, the Performer RPM II (PN 71233) is engineered for optimal performance between 1,500 and 6,500 rpm. It will also clear our SSP's stock hood, and it just looks cleaner and meaner than our current Cobra intake. It even comes with a removable plate so we can port the runners if we want to later.
Previously, our SSP's best e.t. was 11.79 at 115 mph. Hoping for a little more, we're inst
Edelbrock's Performer RPM II intake comes in either grey (PN 7123) or satin black (PN 7123
The upper plenum comes with a removable plate for easy porting access.
Best output prior was 344 rwhp and 361 lb-ft of torque on the Dynojet at Ramsey's Performance (Lutz, Florida). Since dropping the timing to 14 degrees to complement the nitrous, our LX's performance on the street was lacking, so we called Chris Johnson of SCT for some help. He showed up with an SCT multi-program switch chip for our EEC-IV ECM.
After maximizing power output both on and off the nitrous (without having to change the timing manually), we replaced the intake with the Edelbrock Performer RPM II. We also took this opportunity to readjust the rocker arms and replace the valve covers with matching black covers from Edelbrock.
As expected, we noticed a drop in lower-rpm power, but that was only when running NA. That's because the Edelbrock intake's larger runners were not as efficient as filling the cylinders down low, but it's a different story up high. In fact, the power was up by as much as 25 hp at 6,000 rpm! On the nitrous, power and torque were both up above 5,100 rpm, and our Performance Automatic torque converter was certainly going to help keep our coupe in its new higher power band on the track.
The intake manifold comes with all the hardware necessary (right), but extra gaskets can b
We also opted for a pair of black valve covers from Edelbrock to match our new intake. Thi
After disconnecting the throttle linkage and removing the upper intake, we relieved the fu
For our track test, we expected the best, but scorching heat and near 80 percent humidity kept the SSP from running to its potential. Once we let it cool in the staging lanes at Gainesville Raceway (back to ambient temperature of 96 degrees Fahrenheit), we opened the bottle and heated up the Mickey Thompson drag radials. The first hit yielded an e.t. of 11.55 at 117 mph-a best ever for the little coupe, and that was with our big front tires and the front antiroll bar connected. Unfortunately, mid-August heat and traction issues (due to our newly found power) prevented another 11-second timeslip, but we were satisfied with the results. Next time, we'll set up the LX a little better and we expect lower 11s to boot.
Though some power was lost down low, it wasn't enough to be noticeable on the street. As always, we'll continue to tweak our little coupe one story at a time, so check back next month to see what we've done. And if you have any suggestions for what we should do next, send an to email@example.com.
The heater pipe and lower intake came off next.
Be sure to clean the gasket mating surfaces with a razor blade and a clean cloth.
The next step is to transfer the plugs, sensors, and other hardware to the new lower intak
Johnson plugs the chip into the chip programmer and burns the tunes.
On The Chip
Once a staple of 5.0L tech, the "chip" (which plugs into the computer to re-tune the engine) has been all but forgotten. But that doesn't make its affordability and effectiveness any less desirable. SCT makes chips and tuning software for EEC-IV processors like ours, and it's a great way to get a little extra or do simple functions like raise the rpm limiter for not a lot of money. The chip itself (PN 6600) plugs directly into the ECM, is programmable with up to four different tunes, and retails for $269.