Still chasing 10s. New PB 11.38@123.5mph

[Pkeen]

Ah ok ,I knew that it was the rear end to run ,but didn't know why. Thanks for the information !

[Shodown]

I suggest a tubular front crash bar from RSM. I have one on my ZL1 and it saved 10 lbs off the nose.

https://rock-solid-motorsports.com/p...bumper-support

Also have you thought about light weight seats? The stockers are pretty heavy. Look into a set of Braum seats. Those can also save some weight without hacking up the car.

[acammer]

Originally Posted by Shodown

I suggest a tubular front crash bar from RSM. I have one on my ZL1 and it saved 10 lbs off the nose.

https://rock-solid-motorsports.com/p...bumper-support

Also have you thought about light weight seats? The stockers are pretty heavy. Look into a set of Braum seats. Those can also save some weight without hacking up the car.

There are for sure a bunch of places I can get weight from the car. I think that I can find about 100lbs fairly easily (exhaust, battery, swaybar, crashbars, washer fluid/wipers), and then it will start to get a bit more costly. Realistically, I want to keep the car as close to "street trim" as possible, but I am definitely considering some of the possible compromises.

[Domangue418]

Could always do what Hondas do and take a hole saw to the diffuser. What rear sway bar are u using?

[acammer]

Originally Posted by Domangue418

Could always do what Hondas do and take a hole saw to the diffuser. What rear sway bar are u using?

Yea - my problem is that I'm just not willing to cut this up into a race-car. It is, and will forever be a jack of all trades, master of none - but I want to keep it looking nice, and retain all the creature comforts. I realize that limits what I'm going to accomplish. I'm ok with that, but definitely still eyeing places to trim fat where I can.

The entire suspension, including the rear sway bar, its 100% stock outside of solid rear subframe bushings, and poly bushings in the diff mounts. There are without a doubt some gains that can be made there - I expect at some point I will make some upgrades there.

[davidscamaro]

Should try a small safe 50 shot of nitrous. Run high tens all day long

I used a kit on my old s-10 with a SBC V8 swap, went from mid 13's to mid 11's just from a 100 shot

5000 feet DA strip on stock open rear and stock front and rear suspension

[sr530]

There's at least half a second to be gained inside the bellhousing...

Grant

[acammer]

Originally Posted by davidscamaro

Should try a small safe 50 shot of nitrous. Run high tens all day long

I used a kit on my old s-10 with a SBC V8 swap, went from mid 13's to mid 11's just from a 100 shot

5000 feet DA strip on stock open rear and stock front and rear suspension

Yea, would do it for sure. Would like to find it on motor though - keeps me reaching and cleaning up the little things.

[acammer]

Originally Posted by sr530

There's at least half a second to be gained inside the bellhousing...

Grant

If I could just get the TCM on this thing to work right we'd be a lot faster, that's for sure.

I'm not sure there is half a second there, but I do think that shorting the 1-2 cost me a tenth, and there is at least another tenth or two in the shifting. I've got it shifting a little cleaner right before it went away for the winter storage (needed just a little tweak to the clutch stop), I'm hoping to get some more passes in the decent spring air here in a few months.

[sr530]

Originally Posted by acammer

If I could just get the TCM on this thing to work right we'd be a lot faster, that's for sure.

I'm not sure there is half a second there, but I do think that shorting the 1-2 cost me a tenth, and there is at least another tenth or two in the shifting. I've got it shifting a little cleaner right before it went away for the winter storage (needed just a little tweak to the clutch stop), I'm hoping to get some more passes in the decent spring air here in a few months.

If you could stick a 6800 launch, that would make quite a difference.

Grant

[acammer]

Originally Posted by sr530

If you could stick a 6800 launch, that would make quite a difference.

Grant

The pass I shared was 5,500rpm on the 2-step, and that was about the right amount of wheel speed, I don't see it holding another 1,300rpm with this much starting line ratio. Peak torque comes at about 5,700rpm, and it flashes on the initial release, so I'm really pretty close to where I want it to be in the first second of the run.

It might take a little more - tires were at 16psi and just ran out of time to see if it would hook harder on like 14psi. Mostly just needs shifts cleaned up, bunch of weight out, and aero improvements on the rear diffuser.

[sr530]

Starting line rpm is stored energy you make before the clocks start, and then put to work after the clocks start running. Another 1300 on the starting line could add around 130ftlbs for .6 of a second, similar to a short duration 140hp nitrous shot. The key to harnessing that extra stored energy is drawing it out of the engine's rotating assy at a rate that does not upset the chassis.

The clutch is what controls stored energy discharge rate. Your RXT wants to draw that stored energy out at a rate that's too quick, which is hurting your ability to take advantage of more launch rpm.

Here's a link to a page that explains my point of view in more detail...
https://grannys.tripod.com/clutchtameruniversity.html

Grant

[acammer]

Originally Posted by sr530

Starting line rpm is stored energy you make before the clocks start, and then put to work after the clocks start running. Another 1300 on the starting line could add around 130ftlbs for .6 of a second, similar to a short duration 140hp nitrous shot. The key to harnessing that extra stored energy is drawing it out of the engine's rotating assy at a rate that does not upset the chassis.

The clutch is what controls stored energy discharge rate. Your RXT wants to draw that stored energy out at a rate that's too quick, which is hurting your ability to take advantage of more launch rpm.

Here's a link to a page that explains my point of view in more detail...
https://grannys.tripod.com/clutchtameruniversity.html

Grant

Yea - I follow what you're suggesting completely. On radials where you need to keep the tire stuck I use a much slower clutch release to take advantage of exactly what you suggest, storing inertia in the engine and feeding it to the driveline at a rate the tire/chassis can consume.

This was my first outing on bias plys, so my approach is absolutely subject to change, but I went with the traditional stick shift car approach of a quick release (still using preload to mitigate as much shock as possible) and putting the inertia into the driveline and tire essentially in no more than a quarter second, and then letting the tire manage the release of that energy. Which works pretty good with a bias ply, and has the benefit of being substantially easier to repeat consistently.

I can agree that a slipper clutch or a clutch release device, on radials, would be fastest. I'm not interested in running a slipper clutch. A release control device I might try some day - but for now, the wheels I bought had bias plys on them, and I'm going to spend their life trying different approaches to making that kind of tire work with whatever my left foot can do. I have some no-prep airport drag stuff planned for this year, and the bias ply is definitely the go-to for those surfaces, so it may be here to stay.

The good thing is with so much starting line ratio, I have cut back on the need for a long slip - the car is near peak torque (with the clutch locked) almost immediately in the run, and carries the nose all the way to the 1-2 shift. That was the whole intent behind the deep rear gear ratio, and it's working exactly like it should - the revs never dip below 5,000rpm. I know what you're thinking though - if I could hang some more RPM on it, there is more potential there. No disagreement - the chassis is gonna need some work to take much if any more.

I love the idea of the clutch release device, and I agree with the concepts - they all make sense. Someday I may get back to radials and run something like that.

[sr530]

Every single car in NMRA's Coyote Stock class runs a clutch release device on a diaphragm clutch, and they all dead hook with 20+ psi in bias slicks. NA 302cuin factory sealed crate engines on spec fuel and tune running mid 9.70's @ 140 carrying 3000lbs, launching at around 7400. The only thing that keeps those guys from launching even higher is a factory ECU tune that closes the throttle blades if the engine goes over 7800.

NMRA's Coyote Stock is a sister class to NMCA's Chevrolet Performance Stock class that runs the sealed crate DR525's also @ 3000lbs. The CS and CPS sealed engine classes have many common rules and run against each other at the combined NMRA/NMCA World Finals.

Grant