Vesa

Anybody having that?

How it is working on streets? What shocks work with them?

I now have 7-leaf iron spring, 3/4" sway bar, Kyb Gas-A-Just shocks. I´m planning for fiber 420lb with single adjustable QA1 shocks in order to loose weight and hopefully gain better 60ft times.

RunningMan373

i think the stock rate was like 190, on a 9n leaf. a 420 lb is gonna feel like iron on the road.

Vesa

The 7-leaf at least seems to be ok for my anyhow (well im not looking for a soft cruiser that much...)

Van Steel

If it's a strip car than yes thats a good way to go especially with the QA1's. On the street it will be pretty stiff.

69427

I've been running the 420# spring for years. Road course stuff is my thing, but the street scene ride is still very acceptable. Firm, but without the harshness that the friction-plagued steel spring transmitted.

gkull

I had way to much squat with the TRW 340 or 360 mono fiber and went with the equivolent to the 420 inch pound steel. I've put more than 100,000 miles on it and i have never even considered removing it.

I was using 10X28 Goodyear and later hoosier slicks. Running about 9 psi. My old 383 was only a 11.70's bracket racer.

4.11 toms rear end, Smart struts, 3/4 sway, HD trailing arms with the rear toe set to "Zero" with stainless steel shims. I had the Gas- adjust like you. An adjustable rear shock would help with weight x-fer. Because you could set it to compress easy and then hold the rear down with rebound.

Vesa

From what GrandsportC3 has been writing I have understood actually that at REAR you should have very firm spring and shocks set also very firm (not even let it compress easily)??? Maybe he means that then the bcar hits the soft tire more hard ??? I do not understand which one would be the right way to go ??

gkull

Grandsport has large diameter slicks that would probably hit his body. You want weight x-fer without being excessive. You don't ever want to bottom out against the rubber stops. I actually removed mine because I had never touched them anyway with a 420# spring.

The best thing is testing. Get a friend with a quality video camera and have shots taken from the side so you can see what the rear tire and wheel well are doing. Also from behind. so you can see what the car is doing and then try different settings of compression and rebound on the shocks.

Van Steel

With a stiff spring and adjustable shocks, set up at almost the highest setting, you should get about 1" of squat in the rear and good weight transfer. If you have less HP than GrandsportC3 than you will need to tone the shock down. They QA1's has 12 settings on their single adjustables. I believe he has his set at 10 or 11.

GrandSportC3

Here's the problem with the rear if you allow the shocks to compress easy: If you don't lower the strut rod mount on the differential, the geometry will get messed up on rear suspension compression and you'll lose traction. However, IF you have the lowered strut rod mount (or smart struts, the strut rods will be parellell with the half shafts), that concept works well. I don't have the lowered strut mounts (or smart struts) and I can't allow the geometry to get messed up. That's why I'm running a 550 lbs/inch spring and QA1's set to 11 of 12 clicks. Even with 700 HP (on nitrous with the old engine), my rear shocks never compressed more than 1 inch. On 1 inch compression, the change in geometry is insignificant.

gkull

I have the rear Smart Struts set to the lowest racing center mount position. So I don't have camber change with verticle wheel travel.

I had a real traction problem if i left the rear to high and very little squat. Without weight x-fer i could almost do a 1/8th mile burnout.

GrandSportC3

With the smart struts, allowing some compression will work just fine.. However, I think that part of your traction problem was also your front suspension. As you are a road racer, I assume that you have stiff front springs and no 90/10 shocks. My front end comes up a lot which really gets all the weight on the rear tires. The concept of a drag and road race suspension is just way too different. The road race rear suspension works, but the front of such setup is too tight in front. Therefore, the rear suspension has to do all the work and allowing compression will help as long as the rebound is under control. If the suspension is set up for drag racing, not that much help (to achieve maximum weight transfer) is needed from the rear suspension. I was considering smart struts and dual adjustable QA1's for the rear but the price tag has kept me from doing it. My 60' times with my current setup with my old setup were between 1.39 and 1.42 and I never lost traction, so I didn't see the need to spend that money. I do agree that allowing more compression (as long as there is no camber change) will help traction with smaller tires. I use 10.5 inch wide radial slicks (Hoosiers)

Vesa

I have the smart struts. And right now stock steel 7-leaf and Kyb Gas A Just shoks (rear and front). Front I have 550springs. I have all aluminum 540 cid Worls Products engine at 4000rpm it has 634ft.lbs and around 2700rpm it has 520ft.lbs. I do not rev it high so I have less HP than GSC3. 3400lbs with driver. 3.08 rear gear. 26" Hoosier 9" sliks rear. 27" street tires front.
Now you see the problem=the suspension is not for drag racing.
The ultimate for me would be dual adjustable rear QA1 with maybe 360 or 420 fiber spring rear and dual adjustable QA1 front and really soft springs front maybe even QA1 semi coilovers.

But due to money I want to do it stepwise and if it works already with first or second step then I stop investing money in this area and use it somewhere else.

So what would yopu recommend guys?

Step 1 rear: 420 or 360 ??? VBP rear fiber spring with SINGLE adjustable QA1s in rear. This is the problem..do I need the dual adjustable?????

Step1 front: QA1 dual adjustable shoks. And for first season keep still the too stiff 550 springs. Later if needed change to 460 or even softer (I do drive occasionally road race also so it will be a compromize). But dual adjustable semi-coilovers with 350 or 450 QA1 springs would have almost same prise tag up front and weight less and get height adjustability

Current setup:

No load:




On load

Vesa

gkull & GSC3 please comment my previous post!

One more general question about QA1 front semi coilover kit. I was thinking of the shock lower mounting (with those 2 tiny bolts) compared to stock setup...is the stock mounting strong enough because in that qa1 semicoilover setup that lower mounting point must hold both the shock forcess and additionally the spring load ?

gkull

I just ordered the front QA-1 dual adj. with 450 springs. I had the same question about mounting. They mount above the a-arm so they are not held on by two small screws. I was also told that the 450 is actually stiffer than the my front stock type 550# coil.

I'm doing the testing out on the road racing track before another C-3 buys his setup in case another coil over spring rate is required.

I see a couple of things going on in your pictures. What is your rear slicks tire pressure? You only need about 9 psi. I don't know the conversion to metric. The track doesn't appear to be that sticky.

When those rear ware out get 10X28 slicks.

90/10 shocks on the front are a must for drag racing. It might be your cheapest investment to try first.

these are 10X28 mounted on my car. With my 420 steel I have never touch the body to rear slicks

Vesa

So maybe to the front I should go right away with dual adjustable semi coilover kit with 350 springs!!! That would offer me the 10/90 possibility also. As step 2 (and hopefully final step) I might get 360 VBP spring and qa1 single adjustables.

Please comment your testing results as soon as awailable! Both how easy the bolt on is and how do they compare in relation what 550 stock springs have felt alike...

In those picture I had 17 psi and in the afternoon I tried one pass with 16psi. This was some kind of baseline recommendation from M/Ts homepages. So if 9psi is ok and good then it seems I really have way too much presure...thanks I will test next time with lower pressure!

gkull

changing the front shocks in easy. Maybe just buy a set of 10/90 and see how your car likes it.

GrandSportC3

Your main problem is in the front.. It's very difficult to make the suspension work well for drag racing if you have 550 coils in front.. Sure, it's doable to a certain power level, but once you hit 600+ flywheel HP, you won't be able too hook up without addressing the front suspension. (unless you are able to go with super wide tires)

Vesa

OK so I will go with QA1 coil over setup: DGMP4350-1 instead of just 10/90 shoks because I have budgeted to spend a fixed amount of money this winter and that coilover setup and plenty more still goes in that budget...

Vesa

One last question guys! Isnt it also obvious that when entering drag race I should remove my existing non tubular 1 1/4" front swaybar? (havent done so far...)