Drag racing suspension setup??

[IPT]

I need some help with my new car. I have gone from a 1G to a 2G and need some help. The 2G has AGX's in the rear on stock springs. They where installed to help prevent rea wheel hop that caused a broken rear axle.

Questions is what setups are people using?? I was thinking Ground control coilovers.. What shocks shocks should I go with and what spring rates also??

This car is for drag racing only!! I will have to be driven on the street every once in awhile, but not very often.

Any suggestions would be appreciated. Thanks. LAter

 

[cait sith]

If you want to be serious, JIC with drag valving is the current way to go.

 

[3literpwr]

JIC is JUNK!!!! I have dynoed their stuff and the adjuster dont do squat!!
NOTTA!!

The ones that where tested where off a 3000gt. The stock shocks and the jic where run back to back and the STOCK SHOCKS WHERE STIFFER
and the jic had CRAZY spring rate for the street like 800lbs or some shite, but to the owner they felt fine due to the fact that they where not properly damped........ I would not waste your money on that stuff....

AGX have a larger adjustment range.

Ohh as far as drag setup,,,,, you want soft spring rates in the rear with little comprssion control and alot of rebound..... While in the front you need little rebound control and a fair amount of compression control and
a higher rate spring....


Larry
#622 scca club rally
Shock tuner/builder

 

[jtmcinder]

As spring rates increase, the desired amount of compression damping goes down. The reason that 800# springs can ride better than 250# springs is, as you suggested, because of better shock valving. So, with regard to all this, it's not that JICs are junk; it's that raw data off a shock dyno must be interpreted with the associated springs in mind.

However, if you are also claiming that JICs have less rebound damping than stock shocks then I have to suggest that whoever ran the shock dyno was incompetent or didn't know how to read the output. The only other option is that you got a back batch of shocks, which I doubt.

Finally, maybe the drag set-up is different, but I've seen dynos from FLT-A2s and the adjuster has a large effect. So, again, I have to wonder about the shock-dyno operator and/or the batch of shocks.

If you can back up your story with pics of the shock-dyno outputs, that would be great. I will scan in my plots of FLT-A2s for comparison. It might help all of us understand the differences between autoX and drag set-ups.

- Jtoby

 

[IPT]

Originally posted by 3literpwr


AGX have a larger adjustment range.

Ohh as far as drag setup,,,,, you want soft spring rates in the rear with little comprssion control and alot of rebound..... While in the front you need little rebound control and a fair amount of compression control and
a higher rate spring....


Larry
#622 scca club rally
Shock tuner/builder

I have AGX's in the rear so those should be OK?? What about in the front?? I have heard that front AGX's are too long for a lowered car. Koni's in the front then??

What about a coilover setup?? GC's stock rates are #400 in front and #300 in the rear??? I most likely am wrong on those numbers.

 

[3literpwr]

Originally posted by jtmcinder
As spring rates increase, the desired amount of compression damping goes down. The reason that 800# springs can ride better than 250# springs is, as you suggested, because of better shock valving. So, with regard to all this, it's not that JICs are junk; it's that raw data off a shock dyno must be interpreted with the associated springs in mind.

However, if you are also claiming that JICs have less rebound damping than stock shocks then I have to suggest that whoever ran the shock dyno was incompetent or didn't know how to read the output. The only other option is that you got a back batch of shocks, which I doubt.

Finally, maybe the drag set-up is different, but I've seen dynos from FLT-A2s and the adjuster has a large effect. So, again, I have to wonder about the shock-dyno operator and/or the batch of shocks.

If you can back up your story with pics of the shock-dyno outputs, that would be great. I will scan in my plots of FLT-A2s for comparison. It might help all of us understand the differences between autoX and drag set-ups.

- Jtoby

The shocks where tested by a designer and vehicle dynamics engineer for
firestone & Moriss

They where tested on a 100k MTS servo hydralic dyno
And YES they rebound rates where on par with stock!! on ALL four corners...... The gabs we tested at the same time where 3 times the forces....... They also very inconsistan adjusters, 2 of which did nothing......


The company that I worked for tested almost every shock company out there......

What dyno have you tested them on?
I will see if I can get ahold of the data

Larry

 

[jtmcinder]

Cool. I would never knowingly suggest that Moriss Dampers doesn't have anyone who knows how to run a shock dyno. At the same time, however, the people who designed JICs are no fools, either. So it must be that JIC thinks that either underdamping is the way to go for drag racing or we don't have enough other data. Note that I'm more of a side-to-side weight-transfer guy than a front-to-back weight-transfer guy.

The new question for me, therefore, is what's the thinking behind soft shocks for drag-racing. Underdamping would seem the last thing to do when wheel-hop is such an issue. Or are the springs on a JIC drag set-up so soft that even the soft shocks are enough to achieve critical damping or better?

In short: What were the rates on the springs?

- Jtoby

 

[3literpwr]

Ok I put a call in for the gab, jic, stock comparison charts...... We should have them in a few hours......

my thinking behide it is that JIC is in the market of selling street shocks
not race shocks. If they where to sell setups with properly damped 700lbs springs for the street NO one would buy them do to how stiff they are....... I mean you need a race car with race tires to drive around with those rates....... They keep the body roll to a min buy the high rate springs and keep the ride OK with soft shocks......

The data will soon tell!

Im not saying that they are dumb, but rather it may be marketing that is tell how to make a product! Many say that GABs are too stiff for the street! And the gab was a bunch stiffer with a 500lbs spring unlike the jic with the 700-800lbs spring.....


These where sold as road racing shocks not drag

Larry

 

[jtmcinder]

If this was a road-racing set-up for a 2G, then, I agree, that's nuts. But I know that if you call RRE and talk to John M., he will gladly set you up with something around 650/550 with properly valved FLT-A2s, so I know that JICs are not all sprung and damped for the street crowd.

Of course, RRE also wants to make money. So if you insist on crazy rates and promise not to come back and whine that the car handles like <bleeep>, then they'll sell you low-rate springs and low-valved shocks. They're a vendor that you have to work with, not boss around without listening. And they are really worth listening to. I did all this math in advance and decided on 500/400 springs for my Konis. The car still had terminal understeer at autoXing speeds. So I talked to John. After he had a few laughs at my expense, we got me some new rear springs and some offset bushings, and now I love the car (again).

- Jtoby

 

[cait sith]

I am just simply regurgitating information I recieved from the guys over at *some other messageboard where things are a little less BS heavy* who swapped from an AGX setup to the JIC FLT-A2 Drag Racing setup, and are pulling stupid low 60' times.

This is the first negative words I've ever heard about their drag racing setup.

 

[3literpwr]

I have the dyno charts but cant read it at home cuz i dont have excel...
I will post it on moday from work, unless you would like to mo email you it.....

Larry

 

[3literpwr]

Originally posted by 3literpwr
I have the dyno charts but cant read it at home cuz i dont have excel...
I will post it on moday from work, unless you would like to mo email you it.....

Larry

Ok here they are.... If you want more I have them, and raw # data as well..... email me for more [email protected]

 

[jtmcinder]

Hard to read, but interesting. Where the heck do you get a shock dyno that checks 35"/sec, though?

- Jtoby

 

[3literpwr]

Originally posted by jtmcinder
Hard to read, but interesting. Where the heck do you get a shock dyno that checks 35"/sec, though?

- Jtoby

Roush.......lawrence tech.........

If you want more detail just ask!


many, many more shocks too......
koni, dms, advanced design, jrz, hyperpro, many bilstein,kw, penske
shock tek.. (which I can rebuild) and so on....... about 3 years worth.

The best i have seen so far are KW, and hyperpro, both triple adjutbles that did what they should...


Larry