pancherj

Looking for a little help getting my suspension setup ready for a new engine/trans combo. Car has a 355 that will run mid to low 11's. The car was previously running 11.80's with a similar motor, but a 700R4 with a 3600 stall. Now it will be a TH350 with a 4800 stall.


With the old setup, I would regularly pull 1.60-1.65 60' times...but always with some spin about 100' out. I have LCA brackets, BMR lower bars (non-adjustable) and a Jeg's tunnel mount torque arm.


What pinion angle should I shoot for? Should I try to set the lower arms level or slightly raised in the front?


I also have some Moroso trick springs to put in the front along with some 70/30 struts. These are the small block springs. Do they need trimmed? The only weight removed from the front is the AC and headers.


I was never able to solve the tire spin issue. It may be that the 26" tall tires just have too little sidewall. Maybe I need to go to 28" tall tires?

mw66nova

iTrader: (13)

what rear shocks are you running? spinning about 100' out would indicate you need to tighten up the rear shocks on both extension and compression (according to afco's tech how-to articles).

pinion angle would not affect this much, if at all. this isn't a leaf spring car. pinion angle may help dial in things a little, but isn't a major adjustment like on other types of suspensions. get the pinion angle set so it doesn't wear the u-joints or cause a vibration and forget it.

how old are the tires? what tire specifically? tubes? tire pressure? what hole are the lca's in?

as for the trick springs, they'll likely need to be trimmed unless you like the 4x4 stance.

what track do you run at? i will be at South Mountain Raceway on the 26th of this month.

pancherj

Lot's of good questions Matt! I generally run at Numidia...but occasionally Beaver Springs.


The LCA's are currently set in the lowest hole.
The tires were 26 x 10.5 Hoosier QTP's @ 16psi (seemed to be the best)
Rear shocks are Koni (non-adjustable). I do have air bags so that I can preload and the stock Iroc swaybar.


Good info about the pinion angle. I think I had it set at -2 degrees.


It almost seemed to me that the car would hook well, move out past the 60' mark and then spin.

mw66nova

iTrader: (13)

that's definitely a rear shock tuning issue then. i don't know much about those tires, are they a stiffwall tire? If not, i'd recommend looking at a stiffwall tire. even the lightest of thirdgens will benefit from the integrity of the stiffwall.

i'd try to move the lca's up 1 hole. with them in the bottom hole like that, it may be shocking the tire too much, and it doesn't have enough power to keep them planted, so it rebounds and you get a spinning condition like you're seeing now. better shock tuning will help this area too.

you should come out to south mountain raceway on the 26th

pancherj

Thanks Matt. you've given me some good things to think about. Maybe it is time to invest in a good set of double adjustable shocks for just the rear.


Anyone have an opinion on who to go with?

mw66nova

iTrader: (13)

the hot ticket on rears are Vikings. I have them on my car. i'm getting to the firm side of the adjustments as i hammer the suspension tune out, but i bought a set of the shocks before they released a "drag race" version, which i believe has even firmer valving. If i end up maxing these out, i will email them about the drag race valving and if they can be fitted with that.

additionally, there is afco, which is top of the heap, but you'll pay for them, lol! qa1 is out there too, but they have a lot of quality control complaints so it's not one i recommend. strange makes a set as well as i recall that are pretty nice. hard to beat the pricing of the vikings though

no green

Based on my experience, I don't agree with this. I fought for a few years changing everything, then one day I was told to set mine -4 from the driveshaft and it was night and day difference. Like from high 1.6's to low 1.40's, and a few 1.39's. Spohn recommended -3 from my driveshaft with my new torque arm. My 60's are the same with that new torque arm as they were with my old SLP hanging off the transmission. Also, I was just talking with Caltrac today about my dad's truck, and the cliff notes from them was pinion angle was LESS important in a leaf car than these. Again, my experience, FWIW...

However, I do agree his issue is shock related, and pinion angle wont change what's happening 100' out.

I have QA1 DA's. I am happy with them, but you need to throw the directions and their recommendations in the trash. If I were to do it over again, I would go with Strange's from TRZ. but if all you have is a low 11 second street car, some 3 way adjustable might be all you need.

What does the 330' look like?

pancherj

60' 1.624
330' 4.765
1/8 7.424@91.94MPH
1000' 9.731
1/4 11.665@117.20MPH

Car's best pass ever (at ATCO). I came close at Numidia with the DA at 2500'.

no green

That looks like a good pass (obviously your best), but what do they look like when your having issues?

pancherj

I'll have to check. Generally, my 60' times are a bit better than shown above. It is the 330' and 1/8 that take a hit. I don't think the splits change much in the last 1/8.


I'll check my log book when I get home.

pancherj

I did look in my log book and most of 330' times were in the 4.90 range. Most of my 60' times were 1.60-1.64.


I think I am going to invest in the rear shocks. I think I will bite the bullet and go right for the Vikings. I'll let you guys know how things pan out. The engine should be back from the shop next weekend and then I need to install it.