Lowering a Car for ET?

Is it worth lowering, and what kind of change in ET do you get.....I just eliminated my exhaust from underneath the car...Probably could lower it 3.5" now.

Lower CG on a fast car is a good thing.

To me, the critical question is "does it affect weight transfer and launch?".
If none or minimal, go for it!

It helps with aero. May or may not help with ET. Looks faster.

Thats how i understand it. You have to have the power to keep enough weight transfer for traction. So it becomes a balance of cg position and torque that can sustain weight transfer. Look at a modern prostocker launch versus a high ten second bracket door slammer launch. Then consider where thier CGs are and torque available for the first 10 to 20 feet.

Be interesting what effect just that exhaust location might have on aero, vs say slightly turned up, thru the hood, etc

Make the car move forward, not up.

Upward motion is wasted energy. At least, that's my experience in motorsports.

My 72 Duster went quicker each time I lowered the front, picked up a solid tenth and atleast 1 mph.

High CG and upward motion is not needed IF the car hooks. Raising CG acts like moving weight to the rear. My bet on a normal bracket car the gain will be small if any.
Doug

Yes it helps. It doesn't look like your using very many aero tricks.
On your car. There are many. You reduce drag when you lower

If your running slower than 150.MPH in the 1/4 mile it probably won't help a bunch, if faster than 150. MPH it will have more affect

My junk liked the chin spoiler in the front and I drilled holes in the rear valance for air to escape both helped in et and mph a bit......

Interesting responses.....Lack of empirical data makes this mostly opinion then....So here is my understanding:

I used to race RC cars, specifically Dirt Oval as a sponsored driver, and they are not moving at 150mph, but aero plays a huge affect on handling and stability. A good handling car makes faster laps and generally finishes higher in the standings...Even at relatively low speeds like 30mph....

So when I look at my Duster, it sits higher than my Cuda and couldn't be lowered due to the headers. Now that those are out of the way, I can now lower a bunch.....What the results are, I have no idea.

My plan is to lower it, and put a chin piece on it....and then get it re-scaled and the IC changed if needed..

Well my thinking, and NOTHING matters except what a Wind tunnel indicates and a time skip proves, is the directed exhaust out the side in the OP's location could have significant "air curtain" effects on the side skirt area of the car that "could" be very beneficial, at speed, where traction is less of an issue.

I know most of your racing is 1/8th mile where aero mods will have the least effect. Ideally I think you need to test it with the new headers before you do anything else. Just to see if they help or hurt performance.

I get what you are saying but a Duster is already blasting a pretty big hole in the air as it is, not tons of air on the side of these cars I am willing to bet.

Yes, 1/8 mile would likely show minimal bang for buck with aero, but how much does one need to be ahead of the other guy to win?

Lowering the nose may increase your rear down-force

Where are you going to install the o2 sensor and your idle and low speed readings are going to be heavily skewed......

I asked him to install one on the passenger side. Typically with short headers and no mufflers you really don't get an idle reading..I pick the car up tomorrow....So this will be interesting.

Well, stage 1 complete!

Looks good, how is sparkplug access?

Looks like it may require removing the headers, and easier too.

LOL

joe

Looks nice even though I'm not a fan of the looks or sound of that type of exhaust and unless you NEED the bowl vents tied together, I wouldn't and I and others had issues with carbs going lean from not enuff head pressure in the bowls....

Not sure about plug access yet. I can tell you, in going from 2" straight tubes to 2-1/8 to 2-1/4 step tubes is probably not going to make access any better. Seems like the outer corner plugs are nice and easy, and the middle two on each side are going to be the hassle. I know on the passenger side, that is the case. I thought for sure the steering shaft would be an issue, and he got right around it, so we will see....It has to breath better for sure, and we know somthing was holding the car back.

We made multiple changes this year with no change in ET. We went high compression, no change, we went better heads, no change, so that left us kinda wondering what was causing the wall we were stuck at. And I think the old man at Koffles hit the nail on the head when he mentioned headers, and that is how I ended up down this path. I had called them to talk about heads, and flow numbers and he said were not going to get a damn thing out of his heads with 2" tube headers...So flow in has to match flow out, and we never balanced that equation.....until now.

This winter whem I freshen the heads, we are going bigger intake valves....These heads should really make some good power, and we are just missing it.

It also fixes two other issues.

I couldn't lower the car, and I was always catching my header flange on the lip of the trailer......

The dust blown around from previous fenderwell's would just fill the whole car every time I fired it.....Was aweful....and impossible to keep the car even semi clean....

And one thing is for sure, the car was very loud before this, it will now be even louder for sure, which matches the saying I have on the back window..."Does Not Play Well With Others"