Manifold / TB rule revisions

[Greg Amy]

The same as.... the chassis, the motor, or???

Good point. The rule stems from someone - a BMW driver, of course, trying to install a 4-choke ITB intake onto an otherwise-STU compliant engine, that would have provided a distinct competitive advantage. I'll bring this to Eric Heinrich's attention, he can explain more.

If we need to, we'll adjust the verbiage.

- GA

[Knestis]

The "writing a rule to prevent something specific" trap. I believe that's Ad Hoc committee standard error 37.1...?



K

[Greg Amy]

Aye-yup.

[JS154]

Good point. The rule stems from someone - a BMW driver, of course, trying to install a 4-choke ITB intake onto an otherwise-STU compliant engine, that would have provided a distinct competitive advantage. I'll bring this to Eric Heinrich's attention, he can explain more.

If we need to, we'll adjust the verbiage.

- GA

The advantage comes from part throttle driveability, every builder I've spoken with agrees that moving a single TB further away from the head can make the same power as ITB's.

Regardless, the point of the rule wording was because initially it was completely in conflict with it self - originally the rule said you had to keep the original intake manifold unless you changed it in which case you had to keep the original intake manifold. I"ll take a closer look tonight at the wording and what's being asked here and post my thoughts.

One thought I have had is, given the FI car's continuing dominance inspite of weight and restrictor adjustments, I think N/A cars should have more freedom to play with the intake manifold than they do, but I'm pretty sure that idea would be DOA.

[Chip42]

I'm with Eric, and have been on record thinking the same (and more) for well over a year.

in a displacement to weight class with street car origins, using street car parts is a very good way to separate the haves from the have-nots. FI will overcome a lot of those issues and, especially with the more modern turbos, sacrifice a touch of peak hp for huge gains in area under the curve over a NA sibling, even with small restrictors. couple that with a huge industry-wide shift (more true in smaller STL type engines but still) toward low end torque and efficiency over performance, and you get a similar enhancement to the NA cars but a lot less peak power potential in most cars than in a few exceptions. yes, hp/L numbers have been on the rise, but once the rules are factored in a lot of that dies off in lost "gains" and you're often times left with a relatively shitty (for racing) intake and head designed to get 11ty MPG on 7-11's 87 octane. NA generally can't compete with FI under that basic premise. open the rules and let the displacement be the driving force like it's supposed to be (at least more so), and fields will be a lot more diverse, and yes, maybe more expensive. and the gap to FI should shrink.

[JS154]

I'm with Eric, and have been on record thinking the same (and more) for well over a year.

in a displacement to weight class with street car origins, using street car parts is a very good way to separate the haves from the have-nots. FI will overcome a lot of those issues and, especially with the more modern turbos, sacrifice a touch of peak hp for huge gains in area under the curve over a NA sibling, even with small restrictors. couple that with a huge industry-wide shift (more true in smaller STL type engines but still) toward low end torque and efficiency over performance, and you get a similar enhancement to the NA cars but a lot less peak power potential in most cars than in a few exceptions. yes, hp/L numbers have been on the rise, but once the rules are factored in a lot of that dies off in lost "gains" and you're often times left with a relatively shitty (for racing) intake and head designed to get 11ty MPG on 7-11's 87 octane. NA generally can't compete with FI under that basic premise. open the rules and let the displacement be the driving force like it's supposed to be (at least more so), and fields will be a lot more diverse, and yes, maybe more expensive. and the gap to FI should shrink.

Chip..

submit a letter. otherwise it's just an idea that's on some forum somewhere.

www.crbscca.com

[Matt93SE]

I pretty much agree with both guys above-- I've been bitching about the stock IM for quite a while now..

for my 240, it was either go FI with a JDM engine, or go slow forever on the stock intake manifold. The old SpeedVision guys were making ~220whp with that engine built to their specs, which was about same as the current STU specs. Sorry, I need another 50hp to be able to even think about keeping up in a 2.4L.

... So I went to an EP rotary.. It's cheaper there. (yes, I'm going to keep fooling myself with that until I blow up my first engine..)