Tammy's Dyno Compiled Results

The Verdict

The Test

Two cars were compared- Tammy's 1994 PGT with HKS cat-back, Hotshots intake with HKS filter, and Hotshots headers, 41K miles. About $2000 of mods. Rich brought his stock 1994 PGT. It was pretty hot in there and there were only a couple of fans re-circulating warm air for our cars. (I think this engine is pretty seriously affected by higher air temperatures, but I've heard that the DynoJet dyno can compensate for the temperature; I don't know if this was done for this test- James)

Tammy said that on the street, she and Rich were about dead even until third gear, where she could pull away pretty easily.

The Dyno, a Dynojet chassis Dyno, is also capable of calculating transmission drag. Tammy's graph showed a 14hp loss, so peak hp is about 166 hp at the crank. Rick's car would then return 154hp.

I calculated a percentage loss of 14 hp to 166 hp as 8%. Torque of 148.6 then is 161 ft-lbs for Tammy's car and 149 ft-lbs for Rick's car. Please correct me if I'm wrong - James.

Modded PGT

Tammy- best run was 152.2HP@5600. Max torque was 148.6. I did the same thing as Rich for the first two runs, start in 4th gear at 2000RPM and stopping at 6200RPM. For my last run, I took her through the gears, and made 154 HP in 4th. The operator said that's about 178 at the crank (note the explanation about transmission loss above resulting in a lower figure). It was about 87 degrees inside this place also. Well, it's quite an improvement over my last dyno, which was last year. Then I had 145@5500. The only changes I've made since the last time are new plug wires, copper gaskets to stop the header leaks. Made quite a difference.

Stock PGT

Rich- best run was 140HP@5600, max torque of 138. For the first two runs, he put her into 4th gear, kept it steady at 2000RPM, and at the signal, floored up to 6200RPM, then release. He first tried flooring it to 7000, but no use since HP drops off way before that. For the final test he had a run thru all gears....kept her at 2000RPM in first gear, and at the signal floored it up til 5th, shifting each time at 6000RPM. Turns out 4th gear has most of the HP. Rich's car experienced a small burst of HP in 4th gear that showed up on the computer both runs....looked almost like a small turbo would kick in for a second. Anyway, the operator said he has about 164 at the crank (note the explanation about transmission loss above resulting in a lower figure).

Combined dyno graphs

Here is the combined graph. I carefully superimposed the two dyno graphs from Tammy and Rich's cars. One of the scans wasn't completely square, so I tried to maximize the resolution at the relevant part of the graph- i.e. between 5K and 6K rpm. I've left the graph dots for both charts so you can see it is off only by a few pixels at most. This is an unusually useful graph because both tests were done on the same day, same dyno.

Most striking is that Tammy's car makes less horsepower through the entire rev range until you get to about 5.5K RPM. This also explains, I think why she could only pull away from Rich on the street once they got to third gear- the car spends very little time from 5.5K RPM to 7K in first and second gears, but much longer in third gear- allowing Tammy to take advantage of the higher horsepower at the top of the rev range. In comparing a VTEC Integra to the PGT, this effect would be even more pronounced. I.e. low end advantage to Probe, then a big discrepancy from 6K to 8.1K RPM (8,100 RPM is the VTEC's redline!).

January 1998