Knowing what to expect when buying performance products for your 6.5 should be a part of your shopping experience, and advertised power gains should be reflected by those seen during real-world tests. Though individual trucks and powertrains can produce some variability in the power they produce with a particular vendor's performance programming, the averages should reflect reality. The following information is presented here to provide a historical perspective on 6.5 power going all the way back to 1997 (yes, we've been doing this a long time), and to provide a reality check for advertised performance gains.
The stock L65 6.5L TD, which is rated at 190 FW horsepower, has produced time and time again a rear wheel power in the 150-160 range on a chassis dyno. This is roughly 75% (or slightly better) of rated flywheel power. A performance program advertised at 100 additional horsepower (nice round number) should produce an additional 75 on top of the 150-160 the truck made stock, for a total of 225-235 RWHP. I should point out that a number of dyno experts believe adding power does not automatically mean a percentage of that power is also lost to the drivetrain. They say that if a stock 6.5 dynos at 150 rear wheel horsepower, adding a product advertised to add 100 horsepower should produce very close to that at the rear wheels - meaning 250 horsepower RW total.
Is an additional 75-100 RW horsepower even possible - due to programming alone (with no other mods)? Anything is possible, but I've yet to see it - in more than 11 years of watching these trucks being dyno'ed and looking at the dyno data. Those 6.5's that have produced 225-250 RW (and there have been a few) were running a larger turbocharger, an intercooler, large exhaust system, and other internal engine mods. It would be difficult to get there with the factory turbocharger.... and the engine needs a few other mods that allow producing that level of power with reasonable durability.
Early Ford, Dodge and Duramax data are also included to show what those diesel trucks produced during dyno days in years past. Plus, you can see what the LB7 Duramax, with a factory rating of 300 FWHP, actually produces on the dyno (about 75-80% of rated FW power). As a way of comparison, the LB7 Duramax produces 300 FWHP with fueling for 20-PSI boost pressure. Something to think about when attempting to get 300 FWHP or 240-250 RWHP out of a 6.5.
The 1997 & 2000 data were produced on BD's original chassis dyno. All 2002 & newer newer data were produced on their new dyno. There are several different manufacturers of chassis dynos, some of which have been around for quite a while. The age of the dyno, its calibration, correction factors applied, and the operator can all produce some variability in the dyno data. The newest dynos are more accurate than early versions, with the newest ones being able to interact with the vehicle through the OBD II diagnostic port as the run is being recorded. Because of the potential for variability, it is best to dyno your truck/Suburban when stock to establish a baseline. Then, when adding performance tuning, you'll know with reasonable certainty that the power increase you've recorded is a real number. Again, the stock L65 6.5TD should produce a stock RWHP somewhere in the 150-160 range. The numbers shown here represent a 10 year time frame, and should help you identify a good baseline.
A big thanks to www.bd-power.com for providing the public with an opportunity to dyno their trucks.
The following dyno data represents what was recorded while visiting BD's spring 1997 Dyno Day.
http://www.thedieselpageforums.com/p...1997BDDyno.jpg
The following dyno data represents what was recorded while visiting BD's spring 2000 Dyno Day.
http://www.thedieselpageforums.com/p...2000BDDyno.jpg
The following dyno data represents what was recorded while visiting BD during the 2002 Rendezvous in BC Canada.
http://www.thedieselpageforums.com/p...a/500/bd06.jpg
The following dyno data represents what was recorded while visiting BD's spring 2005 Dyno Day.
http://www.thedieselpageforums.com/p...2005BDDyno.jpg
Feel free to post your own dyno data... :)
For a related topic, see: This Thread.
