Dynotests
When Dynotech opened in Dallas in the summer of 96, I soon became a regular customer. Having access to a chassis dyno is very nice.
In all the test below, the car has a Borla Catback, Moroso airbox, Hypertech programmer plus, Homeported heads and 1.6:1 roller rockers.
Removal of MAF screen
Red: MAF screen installed.
Blue: MAF Screen removed
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 301.1 | 318.9 | 302.2 | 318.5 | 1.1 | -0.4 |
It's hard to say if there is any gain by doing this. I never had any ill effects by not having the MAF screen installed, so I left it out.
48mm vs. 52mm Throttle body
Red: 48mm Throttle body.
Blue: Stock 48mm throttle body drilled out to 52mm.
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 302.9 | 320.3 | 305.4 | 323.5 | 2.5 | 3.2 |
A big disappointed to me, obviously. Seems it is as easy to run into the BIB (Bigger is Better) syndrome with fuelinjected cars as it is with carbureted ones. Installing a too big of a carb is a classic mistake. On a fuelinjected car, installing a too big throttle body doesn't hurt power, but it does your wallet.
Airfoil
Red: 52mm Throttle body without airfoil
Blue: 52mm Throttle body with Airfoil
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 305.4 | 323.5 | 306.4 | 321.6 | 1.1 | -1.9 |
You might have seen the ads for airfoils: "Add 11hp and tire-smoking torque in 10 minutes". Right. In defense of the airfoil, it did smooth out some spikes in the torque curve. This is why peak torque went down. One of the spikes disappeared.
MSD6A CD ignition and Accel Supercoil
Red: Stock ignition
Blue: MSD6A and Accel Supercoil
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 306.5 | 321.6 | 310.0 | 326.3 | 3.5 | 4.7 |
I didn't think an ignition upgrade would help, but it actually did. Look at the lower half of the torque curve. There are places where torque went up 7 ft-lbs. Pretty impressive considering it's just a little more spark energy.
Hypertech Programmer Plus
Red: Without Hypertech
Blue: With Hypertech
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 303.8 | 323.2 | 306.8 | 324.1 | 3.0 | 0.9 |
Not any monstrous gains, but 3 hp is better than nothing. Btw, the engine temperature during this test was higher than the previous tests. this is why the engine is down somewhat on power compared to the earlier run above.
Cooldown
Red: Previous best run
Blue: No changes. 20 minute cooldown and NOS sprayed onto intake to further cool it down.
| Horsepower Before |
Torque Before |
Horsepower After |
Torque After |
Horsepower Gain |
Torque Gain |
| 310.0 | 326.3 | 317.0 | 337.4 | 7.0 | 11.1 |
This last run is to illustrate how important a cool engine is for maximum performance.
The engine was let to cool down for 20 minutes, and then nitrous oxide was sprayed onto
the intake manifold to further cool it down (no nitrous was sprayed during the run).
Conclusions
Although bolt-on part such as those above do add some power, the gains promised
in advertised are exaggerated. If you want big performance gains, you have to go with the
proven performers: Ported cylinder heads and a bigger camshaft. Of course there are
alternatives such as a superchargers or nitrous.