I am going to a track in Sealy, Texas and before I go for the first time I wanted to put a little extra in my 2004 lightning. So I bought a Diablo Preditor programmer and now I am stuck in what to get next. I know exhaust is a big thing but then I hear about pulleys. I hear to change top pulley then some tell me to just leave top and change lower then to put it on a dyno. Should I change the top and bottom or vise versa? Got until Friday to make a decision.
Thanks a lot guys,
Go with a 4# lower pulley (cageless). The upper pulley is more difficult to change plus adding a smaller pulley will increase belt slippage. You will get the most HP out of the pulley with a good dyno tune, but many are pleased using the predator pulley tune.
Another great mod is the Factory Tech Valve Body. This makes your shifts much faster and firmer than stock. In addition to making your truck more fun to drive, this mod will actually increase the life of your transmission. Not too shabby… Oh, if you do this be sure to modify your predator tune to drop the pressure back to stock.
I called Borla yesterday. They tested their exhaust on a stock Lightning. Their exhaust increased the horsepower by 8. I believe most other exhaust systems would have similar results. The sound is a different subject.
The 4# lower pulley is definitely the way to go..........especially on the '03-'04 trucks that came with no blower pulley bolt on the upper pulley. Changing the upper pulley for these year models requires changing the entire snout because there's nothing to thread a puller into.
As for the canned "pulley tune" in the Predator....... I'm not sure how much I'd trust it. To me, there's not much differnce between a canned pulley tune in a handheld tuner and a store-bought chip right off the shelf. If you decide to use the default Predator pulley tune, make sure to do a dyno pull and check your A/F ratio. 12.2 - 12.4 is about as agressive as you'd want to go. Anything higher than 12.7 is risky.
You mentioned going to LSR in Sealy to make a few passes. Do you live in the Houston area? If so, you ought to hook up with some of us HALO members sometime. We have access to a dyno every Saturday at Horsepower Engineering and can help you get your truck tuned properly. Our club president is an authorized SuperChips tuner and at least once a year we invite the major Lightning tuners (JLP, JDM, PSP) to come down and tune our trucks.
Last edited by Lightning Rod; 09-29-2004 at 12:52 AM.
The so-called canned pulley tune was extensively dyno tested to be safe on all Lightnings (because they a/f ratio can vary straight from the factory). They spent a lot of time on the dyno with it (I remember the numerous times Patrick talked about it on IM with me). Its possible to get more power than the canned tune has on some trucks, but that requires a/f ratio testing. There's no such thing, really as a store bought pulley tune because Diablo literally has dozens of tunes available. One dealers off the shelf can be completely different from another dealer's. One dealer may supply bad air fuel ratios with a shelf tune while another may give great ratios. Its a matter of proper tune selection and experience plus local factors (air temp, humidity, altitude and the truck itself). For years before SCT and Diablo Revolution, JLP, JDM and PSP all used programs made for them by the chip companies, and the bulk of these were available to all dealers despire what they might have told people to the contrary. A few rare dealers used Autologic to create their own tunes then... but not those listed. Things are different now with the tools available but don't let names fool you, a lot of the speed you see those guys producing comes down to cubic dollar spent, not just the tuning.