iluvmacs said:
Mazda Protege 5-2.0L :equal length header
equal length design retains the stock cats for emission passable direct bolt on to existing first cat. has proved to gain 8-10 whp with an increase of 20ft/lbs of torque.A bonus..moves the power band 700rpms lower!! ceramic coated and polished
How can you gain horsepower when the revs are shifted lower? This doesn't seem like a "performance" enhancement, even though the torque is increased.
Any ideas?
I have an EssentialSPEED tuned shorty header coming. Kevin claims a dynoed 7+ WHP NA with the bundle of snakes; he didn't quote torque numbers to me, but I suggest that 10+ lbs-ft. might be realistic. Remember that a header is dependent on a number of things for increased HP and torque readings. You have intake air volume and velocity--naturally aspirated or forced (hair-dryer blower), cam and ignition timing, compression ratio and other factors to consider.
Most important with today's vehicles is the EMS. The Mazda Protege is very conservative in its programming. To take max advantage of any mods, the EMS should be modified and there are aftermarket units out there. Not cheap, however.
To the point:
You want the power band lower, not higher. The higher you have to rev a street engine to get greater torque, the more you have to row the stick like a boar to keep the revs up between shifts. Racing engines
are horses of a totally different color. They also make max use of close-ratio gear boxes to keep torque losses to a minimum when shifting.
Horsepower is fine, but torque is what gets the car out of the hole. The Italians were notorious for building engines with narrow power bands--screamers that were almost unmanageable without constant shifting.
A current example is the Honda S2000. The earlier cars cranked to 9500 with torque coming in at a high level. They changed the cam timing and the gear ratios in the 2004 for more flexibility in everyday driving. Another example is the Mazda RX-8. Not a slouch by any stretch, but the rap against it is
lack of low-end torque.
Revving a basically stock Protege 2.0L engine to the 6500 redline when the torque curve peaks at around 4000 is basically dumb. You are gaining max WHP above 5000 , but the grunt that twists the wheels has long since dropped off. You're basically revving the engine for nothing.
Regardless of what mods you're going with, you want to shift at the torque peak or a bit above to get the maximum out of the engine. Winding the tach to 6500 may be cool, but unsmart.
If you have access to a chassis dyno, spend the $$ to get a baseline reading with your engine as is, then add headers and other bits taking another dyno run after each addition. You'll know exactly what the gains are with each mod and where the power curve actually lies.
