My '84 Camaro just doesn't seem to like M/T ET Strret-r tires. They are 275/60-15 and they just don't want to hook. My car isn't that fast. Guys FLY on that tire and my high 11 second car just spins them. On the occasion it decides to hook, I have a best 60' of 1.55 out of 10 runs on two different weekends, there are probably 5 that are in the 1.5* and the rest in the 1.7 and 1.8. On the 1.55 run it went 11.68 at 113. But a 1.8 60' and I run 11.96. It is frustrating. This pic was 11.82 @ 112 with a 1.56. This lat time out the weather was cooler, tweaked timing and the carb and had a couple 114mph. I feel the car can run 11.5* IF it can hook

 

What have you got suspension -wise?
Tire pressure?

 

Basically a stock suspension. The front has the sway bar removed, and the 40 year old struts and Z28 springs. The rear is a Moser 12 bolt with a 4.10 gear. The rear lower arms are tubular with poly bushings. The panhard bar is also tubular with poly. The torque arm is a spohn adjustable with a del'sphere joint. Stock rear springs and Comp Engineering rear shocks. The rear arms are in the lowest hole and the pinion angle is at 1*
I leave at 1500-2000 rpm foot braking it. Shift at 6000 and run through the lights just over 6000.

 

I wouldn't be surprised if you're unloading the rear suspension right after the hit. As in squatting.
You say Competition Engineering rear shocks. What kind of valving? 50/50? Seeing as you got OEM struts, it's certainly not a drag racing spec.
I'm in much the same boat as you. While not as fast as it was a low 12 second car, the best 60' was 1.7 flat. Stock suspension with the exception of RLCA relocation brackets (lowest hole) and drag bags. I found the bags helped in two ways. One was that I was able to bias the rear suspension so the car left straight. The other was to add some rear spring and this helped with the squatting.
All of that said, I couldn't overcome the well worn ET Streets (bias DOT slick) and 60' times became progressively worse. New MT Drag radials now (DOT) but no laps on them yet.
FTR: On the slicks, as they aged, I could feel the initial bite, maybe in the 1st few feet, then it would unload.
With little to no suspension working for me, it was what I kind of expected although when the tires were fresher, they would overcome the inadequacies of the stock setup.

 

@IROCZman15 has some great development information on his racing page. Started off struggling for traction and was soon lifting the front tires. Excellent 60's (in my estimation) and he followed the standard recipe of 90/10 fronts, 50/50 rears, RLCA brackets and drag bags.

 

Tire pressure? Radial tires don't like low tire pressure. 20 pounds minimum however they usually work better with more pressure. Something in the 32-35 range. Radial tires don't roll over the sidewall like a bias tire. When pressure is too low, it will actually cause the center of the tire to raise up off the pavement causing less traction. A burnout will show the edges of the tire making a lot more contact than the center of the tire.

How old are the tires?

Is there a rear sway bar? If not then install one. It will eliminate any body roll and help plant both tires equally for better traction.

 

If the front struts are shot it may be causing car to hit tire to much and unloading after. May want to upgrade the fronts to get abit more control back, slow the weight transfer down.

lca relocation brackets should be added and lower them down bottom hole.

That really should do it. It doesn’t take much for these cars to 60 good if track is good.

 

I have the rear factory Z28 bar with poly bushings. The tires are a couple years old. Maybe 15-20 passes on them and a few hundred miles, going to car shows and cruise nights. Tire pressure.....that may be my issue. Driving to the track I run 30#. At the track I started with 18psi, then 16 and even 15. But that wasn't helping. Maybe I was going the wrong way?

 

In that picture, you see that it does get the tire up. But it just yanks it up. It doesn't have the power to hold them up, so maybe it is then unloading the rear? Would 90/10 or 70/30 be better than the old original struts? I don't think the car needs a fancy or trick adjustable strut. Also what about the rear shocks? I don't think the rear Competition Engeneering adjust the way we want? Their website says the rears are 30/70, 40/60 and 50/50. 30/70, I take that as they will resist letting the chassis separate? But squat easier?

 

A 90/10 front strut would allow the front up with 10% of the force required compared to 90% to compress it.
So the front comes up and will have less of a tendency to settle.
A worn strut would allow the front to rise but there's nothing in it to keep from collapsing after that initial "yank".
The idea is to keep the rear tire and fender separated and maintain that seperation. Otherwise, as you can imagine, if the rear springs are compressing, the tire isn't being forced into the track. 50/50 is kind of the go to.
That's the explanation I've been given anyway.
There's certainly more to it.

 

While I haven't track tested my own drag radials yet, everything I've heard or read says more not less PSI is what radials prefer.
At 15 PSI you're in the territory where I ran my bias ply slicks. Poor track conditions liked less air in that tire. I even went so far as to go with 10 PSI one afternoon. The tire hooked but the top end was sketchy!
I'll be starting my radial testing with about 25 PSI and work it from there.
I'll be very interested to know if you air up, will the 60's come down.

 

My '78 Malibu had 29x9x15 Goodyear slicks, and sometimes I'd be around 10psi and you would feel the backend wiggle around. But back to the Street ETr , I thought I seen on the MT website and the tire pressure recommendations are 10psi minimum

 

The web says:
The recommended air pressure for ET Street R tires depends on the vehicle's weight and the tire size:
Vehicle weight 2,500–3,000 lbs
For tires under 30 in diameter, the air pressure should be 16 psi or higher. For tires over 30 in diameter, the air pressure should be 8 psi or higher.
Vehicle weight over 3,000 lbs
For tires under 30 in diameter, the air pressure should be 16 psi or higher. For tires over 30 in diameter, the air pressure should be 12 psi or higher.

 

You need someone to video the car from the side, kinda toward back side of it. See what the tire does, the front does and the rear end does. Slow mo it.

If it feels like it bites initially and then spins, it could be a combination of tire pressure and front end control. Radials can wad over itself if too low. If car is heavy they want more. 18-25 for sure, i wouldnt go any lower. I feel like it would improve with a new strut, not sure which way id go as far as valving. 90/10 should work.

 

That's along the lines of my thinking too Orr.
Some, if not all of this, will be used going forward with my own heap.

Question to those that may know: Once committed to "drag racing" orientated strut and shock combo, that is the traditional 90/10, 50/50 deal, how manageable is that for driving to and from the track?
There are a few racers that say no problemo but I have to ask just the same.

 

Just have to know its not a handling car anymore lol it will feel less stable or controlled in hard turns. Everything else is just normal driving, wont notice a difference.

 

Once the 245/50-16s came off, I never expected it to be a "handling " car anymore. Over winter I will put in some 90/10 front struts, and V6 front springs. I would like the front to sit a little lower.
What kind of specs are guys setting their front alignment to?

 

I never was a fan of v6 springs. I always used base z28 iroc type springs.

 

This chart has been floating around forever.

 

Thank you

 

The big problem with the alignment is the amount of travel 3rd gens have in the front end. If the car rises with 90/10's and stays up during a pass the alignment is no where near what it is at rest. If you jack the frt. of the car up slowly watch the movement of the front tires as the toe and camber changes. It's all going to be a compromise especially if the car is street driven. My car is track only so I set my alignment with the front raised slightly.
I've used V6 springs and they will have slightly more stored energy than using a stiffer spring allowing the front to rise as the weight transfers. I changed them out for Moroso trick springs which really had a lot of stored energy. Make sure the lower control arms move freely, the less bind in the bushings the easier the car will transfer weight. I had solid bushings made by a friend with a lathe.

 

Spending a quiet Sunday morning looking over the forum and reading some old threads trying to keep my head in the game, I came across this:

When I quoted this from MT's website, I was incorrect. They were referring to the bias ply version of the same model name (ET Street R (Radial) vs ET Street R (Bias)). Why they would name the tires with the same R suffix is beyond me. Anyway...

I neglected to include the title to that recommendation chart. ET DRAG® AND ET STREET™ R (Bias). The chart itself excludes the (Bias) tag.

The recommendation for your tire, and mine as it turns out, is:

ET STREET™ R (Radial) AND ET STREET™ S/S
On the racetrack DO NOT use starting pressures below 13 psi.
Recommend pressures: 14-18 psi

Seems the only differences between the two is the tread pattern. They both have the R2 compound.
Your starting at 18 PSI doesn't seem an unreasonable approach and getting to 14 PSI even isn't outside the guidelines. However that doesn't mean that 20 PSI might net an improvement.
This is something I'm genuinely looking forward to this upcoming season. 4 months and counting!

 

I use ET street radial Pro's, 275/60/15. My best 60ft is a 1.24 using 17 psi.
But best to start around 18-20 and work your way down to 16.
I used moroso springs up front to help with weight transfer