Jim85IROC

iTrader: (2)

My IROC has a terrible time getting traction, both in street use and at the track. The current motor is a ****-poor combination of parts which has resulted in a very soggy bottom end with very little low end torque, and yet I still have traction issues with first gear. My best 60' time is somewhere around a 2.1 or so (it's been a while and I can't remember) on my way to a 13.99.

I have BMR lower control arms, BMR lower control arm relocation kit, BMR adjustable panhard rod, Jamex lowering springs, stock 10 bolt with a Zexel torsen diff and bone stock everything else. I have no wheel hop issues... I just have no bite. Tires are 245/50/16 BFG G Force Sport tires.

I have the same tires (except 275/50/17) on my Corvette, and that car hooks HARD with a fully stock suspension.

When I'm done building my new motor, my RWHP is going to be about double what it is now (aiming for 500-550rwhp), and that obviously will necessitate some dramatic traction improvements, so I'm starting to lay out a roadmap now.

I'm guessing that my terrible traction is due mainly to the car being lowered, and more specifically, the effect that lowering it had on the pinion angle. A secondary issue I think is just the weakness of the stock torque arm.

What I'm trying to establish is whether a new adjustable torque-arm is going to be my miracle cure, or if I will need to take a "system-wide" approach to this upgrade.

Ultimately my goal is to get better traction, but I do not want to raise the car's ride height, nor do I want to compromise handling

Yet another thing that I need to take into consideration is real-estate. The car is getting an LS swap with either an f-body T56 or more likely an aftermarket T56 Magnum trans, long tube headers, and an exhaust that's yet to be determined. It's a given that I want to get the torque arm off the tail shaft, but whether I make a custom trans mount that gives me exhaust clearance and a torque arm mount, or I go to a shorter torque arm is all still up in the air right now.

I'm also anticipating that I'll be looking into some sort of adjustable shocks so that I can soften them at the track for weight transfer, while retaining a firmer compression for street use.

I'm also trying to sort out just what I can do with springs. I don't want to throw a taller set in just for track days, but right now I seem to have minimal rear suspension travel. I've considered that part of my traction issues might be due to bottoming under acceleration, though to be honest, I really don't feel much if any weight transfer. I've looked at air bag inserts that go inside the springs, but I'm not sure that making things stiffer is necessarily the right answer.

So, when taking all of these needs under consideration, what opinions have you guys got? Educate me!

Big Dog Chevy

Well you are right on a few things. By lowering your car you made the susp stiff and threw off the geometry. Also with street tires you are not going to get a lot of traction anyway. One of the biggest things you can do to get a better bite and still drive on the street is get a set of drag radials (255/50-16) for the car and when you launch of the line just bring the rpms up against the foot brake to about 800-1000 rpms then nail it. That allows your TC to flash and not shock the tires so much. That has netted us 1.65-1.7s 60 ft with that tire size and bfg drag radials. You don't need to spend a ton of money on you susp to get your car to hook you just need to find out what it wants.

89ROC-Z

iTrader: (7)

^^ he's not an auto...


You obviously don't have to upgrade the aftermarket parts you already got. What hole do you have the lca in? Have you checked your pinion angle?

I think the biggest problem is the shocks. Save yourself some money and get fox body strange adjustables. They're alot cheaper than the 3rd gen specific ones, and only need a little lower mounting change (search for it i know it's around here someplace).

I've been looking at torque arms aswell, but if i get a 9" i'll use a madman. Otherwise for a stock axle mount ta the BMR looks great.

I'm having the complete opposite traction problem on the iroc...off the spray i can barely get mine to turn over lol although the clutch hates life right now!

Jim85IROC

iTrader: (2)

Thanks for the info guys. Different tires will definitely be part of the equation, but I won't use them to cover up other suspension problems. My car doesn't bite nearly as well as it should compared to other similar cars with street tires, so it's obvious that I've got work to do before I get involved with tires.

Right now I've got the LCAs in the lower set of holes.

Since I actually drove the car yesterday, it got me thinking about the suspension on my way home, and as I hit the same bump that I always hit on my way home, and bottommed out the car like I always do on that bump (most of my other cars don't bottom out on that bump) it got me wondering if indeed my rear shocks are part of the problem. The car rides firm, probably due to the Jamex springs, but on those quick bumps, the shocks don't seem to be able to damp the motion... they're the stock 25 year old 100k mile shocks. Maybe it is indeed time to start looking at shocks.

Big Dog Chevy

My bad I see now you are a T5 guy, well that makes is worse (really shocking the tires). Having a lowered and stiff suspn is good for corners but bad for drag racing. For the track just get some 15x8" wheels and some good drag radials or for street/track just throw some good DRs on your 16s. It will make a big diff compared to street tires. A 2.1 60 foot with a stick and street tires is not that bad. DRs will knock off .2-.3 tenths with no other changes. Adj shocks are a good and cheap idea too. I have frnds that pull 1.3 60s on the back tires with the stock shocks, TA and LCAs that has been welded up (didn't believe it untill I saw for myself) they put some of the take offs on youtube.

Big Dog Chevy

Damn 100k mile shocks lol, yeah get some new ones.

Jim85IROC

iTrader: (2)

Ok, let's discuss these Mustang shocks a little more. I did a search here and on ls1tech, and in both cases I'm only finding TJ's post. I'm still a little bit lost as to exactly what's needed to use the Mustang shocks. Anybody care to help clarify?

bluegrassz

iTrader: (3)

I would like to know more about this also.

Big Dog Chevy

Why not just get some Competition Engineering 3 ways for $80 bucks a set or Summit 3 ways for $52 bucks a set and bolt them right on (I run the summits). The Mustang rears cost the same I think. I don't see why you guys are having a hard time hooking with these cars.

Gumby

Id go slow on the parts swaps, but yea new shock before you change anything

Though Im sure you know but downshift n nail it if you don't wanna bottom out. I don't have that problem inthe Bird but my wagon comes down hard over many and nailing it just before the bump keep the car in the air.

89ROC-Z

iTrader: (7)

As you saw in his posts, the only thing you have to change is the way the shock mounts on the axle. The camaro shocks bolt in parallel with the car, while the mustangs need to be mount perpendicular to clear the adjuster.

You could bend a U and weld a bolt onto it to get it to work, or weld the U directly onto the axle shock mount which is what i would do...seems stronger

Jim85IROC

iTrader: (2)

thanks, but I'd rather just fix the busted crap. Plus, I'm not sure how flooring it is going to help with the bottoming. If anything, I'd expect the combination of weight transfer and a bouncing rear end to just make things way worse.

gregsz-28

iTrader: (1)

To use mustang shocks, you just need to use mustang shock brackets. They bolt right on. You can find them in t-birds as well.

Gumby

The engine torque holds the car up, trust me on this one.

The main drag to downtown has a set of tracks, lvl on 1 side and a good ft+ drop on the other. It will bottom out anthing you got even with A1 shape parts if you don't slow down to 20[cept a jacked up truck], but if you want to make it between lights you can't slow down. I could skip over that with a full load of friend in my 2nd gen Aro like running over a pebble. Just before the bump you nail it.

If you ever road 4 wheelers its like going acorss a freshly plowed field.
If you go slow its a wacky wonky ride and you twist n get tossed all over the place, but nail it and you ride on top of the bumps like nothing is there. Where I learned that trick.

works good on bumps and uneven RR tracks.

Big Dog Chevy

So what are you saving by using the Mustang drag shocks (I don't get it). You have to mod the rear in order to get them to work but how much do they cost. $52-55 bucks a set for 3 way drag shocks is a deal to me and unless you can get the Mustang shocks for $20 bucks I don't see where it's worth it. Maybe I'm missing something here

89ROC-Z

iTrader: (7)

Strange 10 way stang shocks are ~70 a piece, while the camaro ones are like 120 IIRC.

You get what you pay for with shocks and struts

Big Dog Chevy

LOL, man you don't have to buy 10 way adjust shocks to get a 500hp third gen to hook (No disrespect). We 60 better than a lot of guys that dump a whole lot of money their cars on stuff they don't need. Check this out on youtube, http://www.youtube.com/watch?v=8ykx1kzb0ro That's hooking!! These are my guys cars, the blue one is all steel with a fiberglass hood and a SBC with Stock supsn with stock Monroe shocks out back pulling 1.2s-1.3s with the back tires. My car hooks just as good. Just get some regular ole 3 ways and save your money for some good drag radials if you want a better 60ft time. We 60 1.6s-1.7s on 17" DRs with 3.42s out back without even trying. Trust me on this

Jim85IROC

iTrader: (2)

I'm more interested in the idea of adjustable shocks so that during the 95% of the time that I'm not at the drag strip, I can have a car that handles like a lowered IROC should, but can still give me the grip I want when I'm at the strip. You know, have the cake and eat it too.

89fbirdformula

Odd, ive cut a few 1.7, and tons of 1.8 sixtys on my junk 245 dunlop's lol




that was probably a 12.80/13.00 pass..car was running like **** that night..and you know my cars a banger, stock suspension/shocks with 60k some odd miles.

Jim85IROC

iTrader: (2)

All the more proof that my car has some specific deficiencies, most likely associated with bad/worn shocks and lowering.

89fbirdformula

being lowered might have something to do with it, when my formula that i had when i was 16 got lowered it would blow the tires off into 4th with the procharger, beforehand it wouldnt do much more then scratching into second..

Big Dog Chevy

I can understand that. But with 10 ways you won't see a big improvement other than the extra money. I have two third gens and built many more. As far as corners, you will max out your 16" tires before you need any fancy shocks. You bottom out over bumps because you don't have enough suspn travel and bang the bump stops (I did the lowering springs to back in the day). 17" or 18" on the street with DRs at the track is the way to go. But I feel you with the cake and eatn too