2019 RCR #2

[Al F.]

Rule reference 6.14

Recommended Revised Wording

GM 5.3L LS Engine Option GM cars may substitute the engine long block assembly with the Gen III 5.3L LS series LM7, L59, LM4, and L33 long block assembly from 1999- 2007 GM trucks. The intake, exhaust manifolds, and all external accessories and electronics from the Late GM 5.7L LS cars must be retained for 4th gen cars. The 3rd gen cars may use the truck accessories. The LS1 camshaft may be used in the 5.3L engine.

Reasoning for change:

Will decrease series cost because truck accessories are dirt cheap if not free and they fit better than the 4th gen accessories into a 3rd gen.

Will provide more clarity because the L33 came in 05-06 trucks and a scant few 07 classic body style trucks. While the L33 did come with more compression, more cam, and better heads than the other 5.3s it is still less motor than the 5.7 LS1 and is still a cheaper alternative. The LS1 came with at least 3 different cams, so chopping the verbiage to allowing the LS1 cam in general seemed most fitting. Arguably the best cam for a 5.3 LS in CMC would be the late cam which is also found in 6.0 LQ4/LQ9 engines so they're plentiful and cheap.

[Dustin M.]

We could open up accessories completely.

GM 5.3L LS Engine Option GM cars may substitute the engine long block assembly with the Gen III 5.3L LS series LM7, L59, LM4, and L33 long block assembly from 1999- 2007 GM trucks. The intake, exhaust manifolds, and electronics from the 5.7L LS cars must be retained. Any factory 5.7 LS1 camshaft may be used in the 5.3L engine. Accessories and mounts are open, provided they do not give a performance advantage over stock.

[MHISSTC]

Dustin, the way you have it written it becomes unclear as to who makes the determination as to if the accessories provide an advantage or not. This only complicates things similarly to the aero rule, "if it looks like aero, then it is aero" and the "if it looks like ram air, then it is ram air" arguments we are already getting hung up on. It also allows anyone to use any style of aftermarket serpentine belt setup offered by a number of different companies, some of which are pretty darn expensive, but offer no real gain beyond having some eye candy.

I do like your intention to simplify the rules while making more cheap parts available to everyone even though those parts may not have originally shown up in our race platforms from the OEM. On the Ford side, this would be akin to allowing ALL of the Ford Explorer accessories to be used as-is even if those specific accessories or brackets used to mount those accessories were never actually offered in any Mustang or Capri.

Can the rule suggestion to modified to say something like "any accessories offered as direct OEM replacements in any of the currently allowed manufacturer platform, or any other OEM accessories designed to fit any of the engines blocks and heads currently allowed in this race series." ?

[Dustin M.]

The wording can absolutely be changed. That's the point of posting it here is for feedback to make it as good as it can possibly be. I'm told there are stock replacement aftermarket mounts floating around that are cheaper than used OEM so I'm trying to capture that as well. Here's another tweak, maybe for the aftermarket stuff we can just specify part numbers?

GM 5.3L LS Engine Option GM cars may substitute the engine long block assembly with the Gen III 5.3L LS series LM7, L59, LM4, and L33 long block assembly from 1999- 2007 GM trucks. The intake, exhaust manifolds, and electronics from the 5.7L LS cars must be retained. Any factory 5.7 LS1 camshaft may be used in the 5.3L engine. Any OEM or direct OEM replacement accessories and mounts are allowed.

[MHISSTC]

I always like phrase such as OEM or OEM direct replacement.

I used to think that was a pretty straight forward concept, but wasn't there a little bit of an argument with the Spec MIata folks this year at Nationals as to what would constitute an OEM direct replacement part with regard to axle shafts and how allowable tolerances could come into question?

With regard to OEM and OEM direct replacement, last year the coil rule was changed to use any aftermarket ignition coil, cap and rotor after we asked a few questions and provided some data points on the current prices of aftermarket caps, rotos, and coils. We never actually submitted a rules change request. I guess we changed the rules without even trying. The issue there was the aftermarket products had become cheaper than the OEM, much like the accessory drive you are suggesting. The aftermarket coil manufacturers will tout benefits over OEM all day long in their advertising. What you have to realize is that no matter how good a manufacturer claims their product is and what kind of gains it could produce, you have to analyze the particular situation in which it is being utilized. Yes, theoretically, the Accell cap, rotor, and coil we use could provide an improvement over OEM in an engine built for much higher performance by still providing a spark within an engine operated at much higher RPMs and at much higher compression ratios where the OEM system would fail to operate. But you have to realize that benefit over OEM is only seen in those types of engines. For our little engines running stock heads, cam, intake, and compression, it doesn't do jack squat for us in the way of providing an advantage, because all it does is make a spark jump across a gap to ignite fuel in a combustion chamber, and there is nothing special about that spark that would do anything to improve the performance of our engine.

So, I'm good with the way you rewrote the proposed rule. If it's cheaper and it still allows a belt to drive the water pump, alternator, and power steering pump while managing to securely attach those accessories to the front of the engine, sounds good to me. You could probably find a way to make the lighter stronger brackets out of titanium, or some super small and light super race alternator or super efficient low energy draw power steering pump, but all that is going to cost more money than it's worth.

It could be phrased OEM or less expensive OEM direct replacement mounts and accessories, but that's not as simple as the way you have it already.