Looking at the various Dyno graph outputs I have seen curves all over the place. This got me thinking what do we want the idle curves to look like based on end goal. By goals I mean Towing, Economy, Street Power, 1/4 mile, Competitive Pulling.
I have seen:
Tunes that: Torque shoot up at a sharp angle to a early RPM peak and the Horsepower jump up early as well and it flat
Others that have torque making a even arc up and down thru the RPM band peaking in the middle with HP making a gradual upward curve to a high RPM peak
Some with very flat HP and and torque curves
So what is "ideal" for what?
Also what about the trade off of higher torque peaks for broader HP bands or later torque peaks etc..
I also have seen it said a number of times to much toque to soon is not good. Sometimes I see much higher torque peaks for the same HP as a tune with lower peak but at a higher RPM thus the same or more HP
So what would we want to see for the various tunes we all tend to use:
Street Tune( general day to day use):
Race or Track( 1/4 mile): ?
Pulling(would this differ):?
What about one looking for the max HP regardless of usability Call it a Dyno Tune:?
Also how does Cylinder pressure and timing (SOI) play into all of this?
What is the safest for the engine?
Are there generally accepted curves patterns for each of these or is there large various in view points from tuner to tuner.
Where do we want to see peak torque come in. How much is too much?
what got me thinking about some of this was looking at a post by [email protected]
PHP. He was posts some of the preliminary data from his blown engine questionnaire. One of the things he mentioned was that it seemed many of the engine failures had come from relatively stock motors and from use of what many tuners label the 80 HP Tow Tune. In thinking about towing a lower RPM peak torque would be beneficial but what would that mean from a engine stress or cylinder pressure standpoint. Now as that would also likely give a great seat of the pants feel to it for someone that decided to WOT
it going street light to streetlight, many may like to use that tune as there general use tune or the one they leave it on by default. Then use that tune to really work the motor hard thru the entire RPM band @ WOT
etc.. If torque to early tends to break stuff easier would that stand to reason this would not be a good thing. What tunes put the most stress on the engine if use for WOT
. That then opened the door to what would be considered the ideal curves for these various end goal uses.
Also Diesel Power Magazine in the Feb printing release the article on its dyno and testing of 4 popular tuners tunes. It was a not to highly modified 97 F350. What was funny is they had Beans Stage 1 Sticks in it but did not try his tunes for the test?
Unfair advantage maybe?
Anyways for those that have not seen it. It was Tony [email protected]
Diesel Performance, [email protected]
Truck Shop, Tade [email protected]
Diesel, and Jod[email protected] DP
Here is a link to the article: