Drag Setup Proposal

[WeDgE]

Since I'm close to finally completing my 1JZ swap, I've been thinking about drag racing again and how I should setup the car while maintaining streetable-ness. Here is my proposed setup, any and all feedback is appreciated:

- RX7 rims in rear with 26x10.5 MT ET Streets OR 15x8 Welds with 26x11.5 MT ET Streets
- Quick Disconnect Sway Bar Links in Front
- Set TEMS to Soft, pull TEMS Fuse or unplug actuators
- 2-Step Launch Control care of MS3


Currently, the car is outfitted with H&R springs and Tokico Illumina II struts. I've read that a completely stock spring/strut combo works very well, but I'd rather not have to go through the hassle of swapping springs/struts in and out of the car everytime I go drag racing.


Now this is the part I came up with myself and would like the most feedback on:
- Objective: Increase rear suspension travel/height
- Purchase coil spring lift "puck" (same type used on coil spring lift kits, ex. Jeep TJ)
- Cut puck in half and machine a groove into the side that will allow a T-bolt clamp to rest in (this will allow the puck to remain in one piece when it is installed at the track)
- At the track: 1)Jack up rear of car, allowing suspension to rest 2)Compress springs with coil spring compressor 3)Insert coil spring lift puck halves under or over spring and fasten with T-bolt clamps 4)Undo spring compressor and lower car

Now will this increase weight transfer upon launching? Will it decrease spring pre-load, effectively making the spring softer? Is a 2" lift puck sufficient, or higher/lower? Am I way off in left field with my thinking?? :aigo:

 

[GrimJack]

I'm not sure I follow what you are trying to do here. It sounds like you're lifting the rear end, which is the opposite of what you want.

 

[WeDgE]

It's probably my flawed logic at work here, but I was thinking that extending the shock/spring combo would effectively make the spring "softer". Essentially, I'm looking for a way to soften the rear spring without actually swapping it out...doesn't seem possible from the sound of it. LOL


It was just a thought I had after seeing all the domestics at the drag strips over the years utilizing a raked stance...figured it'd work on the Supra as well...but I suppose it won't work for IRS.

 

[Poodles]

It's a catch 22. More squat = more camber = less contact patch.

Keep it simple, run what you have then get sticky tires, after that mess with suspension setup.

 

[Devin LeBlanc]

Yeah, Most people think the more the rear squats the better, However you want the rear end to lift up when you launch, for every reaction there is an opposite reaction. So if the rear end lifts up it pushes the tire into the ground..

One work.. Anti-squat! 240sx's have nearly no anti-squat

 

[Moy]

Anti-squat. Aka if you have properly functioning TEMS, then when you hard launch the TEMS should kick into hard mode (3 lights), giving you more contact patch and better grip

 

[WeDgE]

If you're trying to prevent squat, why do they say to disconnect the front sway bar (promotes weight transfer)?

So, all I'll need are sticky tires and leave the TEMS to do it's thing?

 

[NashMan]

i plan to 4 link my car next year some time gonna be pimp

 

[GrimJack]

If you're trying to prevent squat, why do they say to disconnect the front sway bar (promotes weight transfer)?

So, all I'll need are sticky tires and leave the TEMS to do it's thing?

There is a difference between weight transfer and squat. It's subtle, but it's there.

Ideally you want to adjust your rear suspension so you get the max contact patch at max squat... but then it's useless for driving anywhere but on the track, so it's kind of a catch 22 situation. Unless you are willing to mess with the suspension setting every time you go out to race!

 

[WeDgE]

There is a difference between weight transfer and squat. It's subtle, but it's there.

Ideally you want to adjust your rear suspension so you get the max contact patch at max squat... but then it's useless for driving anywhere but on the track, so it's kind of a catch 22 situation. Unless you are willing to mess with the suspension setting every time you go out to race!

Understood.

I'm sure it'd be quick and easy to set a few degrees positive camber with those Beech Performance suspension arms?



I'll go with sticky tires, disconnected front sway bar and 2-step.

 

[TurboStreetCar]

Your setup depends on what exactly you plan on doing. My plan is the car remains the same where ever i drive it. Because of this i set up my car to work at all times especially on the street as 98% of my driving is on the street. Im building it as a compromise between a Race Car and a Daily Driver. Enough go fast parts to go fast without taking away the driveability and comfort of the GT car it was ment to be.

If your planning on making the car work on the street drag radials are best as slicks tend to work worse on the street then DR's plus they need to have sufficient heat in them to provide the most bite. There also very sloppy at cruising speeds and on turns.

Im running a 275/60/15 MT ET Street Radial on Weld Draglite 15x8 5.5 backspace. I have a stock suspension with KYB GR-2's and and Auto with 3000 SIP converter. They hook pretty well but do have there limits. I can smoke them quite well if i try but for the most part they hook. They also rub pretty badly, at stock height.

If your building the car as i built mine, Id recommend the 275/50/15 on the same wheel as there VERY lightweight and 2 inches shorter (26" Tall as compared to 28' tall for the 275/60's) and they should fit better on a lowered car plus the tread is 1 inch wider (i thinking these will be my next tire as im tired of the rubbing).

If your building the car preparing to swap parts for the track then i would go with stock wheels or RX7 wheels with slicks, 26x8-9 inch will be fine and provide pleanty of traction as long as you heat them good. Id recommend Bias ply front runners in this situation as well.

I would leave the front swaybar alone as its not something that will make a major difference compared to the effort involved and without it street driving will be ill effected too much IMO.

The reason you want lift in the front end is because it will transfer weight to the rear tires. In the rear you want a softer spring but stiffer shocks. The softer spring will allow some rear squat but the shocks will provide the push from the body to plant the tires. Making a spring softer without physically modifying the spring is impossible unless the spring is preloaded.

To help with your ET and 60' Get lighter replacements for anything that turns (driveshaft, wheels, tires) and practice to get the best launch possible. The ET is dependent upon it.