I dont know whether to say thanks or not for this thread as it could start a war. Tried doing it once before and it got nowhere but a big argument. I guess someone had to start this discussion here, and better to have a respected DMax racer/puller like Michael do it than a nobody like me. Im flat tired of the BS myself.
I tried to pattern my truck off what mods the Spruill's did years ago as nobody EVER questioned their run's validity, and I respected that they tried to do things above-board. Anyway, since I have more than a vested interest in this list I may as well put my .02 worth in. Take it for what its worth.
Mods that shouldn't be allowed are things that make the truck unsuitable for the street or take the truck away from its other possible jobs (towing, hauling, etc).
That will drop the guys who are running their trucks as "race only" vehicles that might see the street only for a few miles in a rare instance and would not be used to pull a trailer or haul a load..
1) I agree with the turbo. It has to be untouched and meant for the model engine its on. Its the basic piece that all this discussion revolves around. NO "stock-appearing" turbos. No twins.
2) Your CP3 choice does not address modded regulators and suction pumps (bag of parts). Are you including those in the LBZ regulator exception? I agree, no fully modded pumps like Floor It or Wicked.
3) Injectors are either way with me. I believe that the single stock CP3 (even an LBZ one) will not hold up to high pulse with larger injectors, so it kind of evens out in the end.
4) Drag radials are borderline to me, since they dont allow the truck to be used for towing/hauling, but they are still a DOT type tire. Slicks are definitely out.
5) Yes to manifolds and uppipes, as they have become common upgrades for all incarnations of Dmax.
6) Due to the O/H potential, I dont know of anyone running JUST electric fans on their DD truck, let alone anybody silly enough to tow a trailer with just that setup (is someone that nuts?), so those shouldnt be included. Plus, the parasitic draw from the fan does count for something.
7) I voted ONLY for the piping part of the intercooler choice. Many LLY/LBZ guys have swapped their IC pipes out, but I do not believe intercoolers should be part of this discussion. A stock truck shouldnt need one, and for the cost, they are not a reasonable mod.
8) EGR should never have been installed on these engines in the first place. You want to delete it? More power to you. No opinion on Y bridges.
9) LBZ mouthpieces on LLY turbos are common swaps, and intake horn mods and wastegate mods are common for LB7s. Downpipes are available to all models, too.
To add...
a) Heads have to be stock or stock replacement. No porting. No oversized valves. Not sure about springs or pushrods. Replacing LB7 heads with LLY or LBZ ok.
b) Stock cam.
c) Stock waterpump and belt routing. No electric pumps.
d) As for suspension, shocks can be adjustable racing type as long as they are still compatible on the street and bolted in stock locations. This includes QA1 and Rancho. This eliminates trick setups like Trent's both-behind-the-axle setup, though. Springs can have leaves removed or 1/2ton springs installed. All common front suspension improvements (sleeves, braces, centerlinks) allowed.
e) Weight reduction is allowed unless it interferes with the vehicle safety or driveability. Id like to see it where guys have to keep their hoods and front bumpers on though. Again, could you run it on the street like that? I saw those pics of the 50K race and thought the guy stripping his truck to the frame in order to win should have been disqualified.
Removing seats, rear bumpers, etc ok.
f) Vehicle should be a production GM truck (2500hd or 3500) that had a Duramax option. No 1/2 tons, no shortened 3/4-1 ton trucks, no cars. The only exception would be putting Dmax's in 3/4 ton Suburbans similar to what TDIGuy is doing, as that comes out as a "factory" install.
g) Added safety equipment should be part of the discussion, shouldnt it? Driveshaft loops at a minimum, both for front and rear driveshafts. They are easy enough to fabricate or buy from vendors, and are just smart insurance.
I think that covers my opinions.
