Cant Hook

[TurboTerry87gn]

I just can't get this thing to hook at the track and I'm tired of wasting money.

All this is with a TH400 on the transbrake.

Sock suspension I went 1.6 sixty foots on 275 BFG drag radials no front sway bar, and air bags adjusted to many diffrent settings for each combination listed here after, KYB shocks, I heat the tires a little, I heat them alot...

Put welds on and 28 x 11.5 x 15 et streets and still cut 1.6 sec 60's

Put Edelbrock upper adj. control arms to adj pinion angle. same

Put on metco lower control arms same, added the instant center brackets that came with the arms, same 60 foot time

Put on compitition engineering rear drag springs and front drag springs same 60 foot. Put on front drag shocks set at 90/10 70/30 60/40 still using kyb's in rear.
Took off the comp. engineering front springs as the driver side spring collapsed over time.

Now I'm thinking about adjustable rear shocks and a wolfe racecraft rear sway bar. I talked to another buick guy at the track that suggested running stiffer sidewall slicks, but I'm going to notch the frame and use the 325 MT drag radials now.

I can leave at about 10 lbs any more I just blow the tires away. 6.7's in the 1/8 at 103mph with 1.6 sixty foots....just want low 1.5 would like 1.4's

 

[Chuck Leeper]

What are the videos telling you?
Chassis pitch rotating?
Tire spin?
Engine tune?

The HR bar is a good option, but the problem should be found, B4 you start throwing more $ at it.
I think I'd look at a set of dbl adjustable rear shocks. Could be the tires are not being planted, [or being planted too hard]. The videos should help there.

 

[Luke]

Hmm...

I understand your frustration. Take what I have to say for what it's worth what worked for me may not work for you. I used to have the same traction problems you described except it was a 4 psi launch that was my magic number. What solved my problem was 28" 275/60R15 MT ET Street Radials (the Turbo 400 w/ T-brake may also have had something to do with it ) I haven't been to the track yet but I just launched of the transbrake at 7psi 2-step at 3200RPM in a parking lot with no burnout and 27psi in the tires. I haven't had time to try a lower tire pressure so for now I can only imagine what it'll do with a John Force burnout and 12-14psi in the tires at the track.

1.)You mention BFG DRs and ET Streets (Bias-ply) but Did you ever use a set of true Drag slicks? Maybe you should consider going taller? I went wider and was disappointed. On my old 200-4R, I went from the 235/60R15 to the 275/50R15 on welds. Every way I tried, I still cut the same identical 1.73 60' even though with my other modifications I was running an entire second faster in the 1/4. I could't leave with any more boost dispite having 2" more treadwidth on each tire. If a 28" slick doesn't work for you, perhaps the 29.5" will? I'd ask around on the forum to see what improvment the 325/50R15s will have over the 275/60/R15s before wasting more money and time notching your frame (even so, the 325s do look great). As I'm sure you already know or have heard, the MT Radials do hook better than the BFGs but are pretty expensive and don't last as long. I still find it hard to believe but everyone swears the MT Radial Streets hook better than the MT Bias-ply Streets.

2.) I know I'm going to get a negative response for this one but one thing I did that helped my traction on my old setup was remove my airbags and use an anti-roll bar. Even when I had no air in the bags I could feel the airbags keeping my springs from squating. I'd feel them rebound after a shallow squat like it was bouncing them right of the pavement. After installing Adjustable UCAs, LCAs, LCA Relocation brackets, setting pinion angle to -5, Wider ET Street Radials, Skinnies up front, Remove AC, Relocate Battery, the only thing that sligtly helped was ditching the airbags and using the Spohn Anti-roll bar (Yet, that may have been due to the sheer amount of weight it added to the rear of the car Seriously, It's was a heavy piece) Another benefit of the anti-roll bar is that it allows you to more safely remove your front sway bar. With my anti-roll bar there is very little body roll. I couldn't even tell it was missing.

If you using the rear "Trick Springs" I think you're talking about you should take out your airbags since they're supposed to serve the same purpose, unless you've already done so. For what it's worth, I read a thread about someone using two softer drivers side Trick Springs saying the car had trouble leaving straight on a launch... This may be worth investigating if you use the anti-roll bar since you won't need one spring harder than the other. I got in touch with Moroso about this and they informed me I may be able to buy two driver's side springs from Dick Miller Racing.

3.) Pinion Snubber - It's not in your list of mods and way off topic but when the hell has that f**kin' thing ever helped anybody's 60'?

4.) For a while I was wondering if my differential was slipping, causing one wheel to slip causing the other to spin. Find out if you can rule this out somehow.

Good Luck. Take a break to think about what's happening and let the answer come to you. you'll be seeing 1.5x 60's in no time.

-Luke-

 

[POWERBRAKEBOB]

Wrinkle Walls

Well, It Has Been Awhile Sine I Drag Raced, I Had A Z11 409/427 In A 55 Chev As A Teenager. I Learned So Much About Drag Race Starts As A Teen. I Learned To Throw Full Throttle Power Shifts (without Missing) As A Teen.. I Drove My Car To School And Towed It To Lions (1969) When I Broke A Rear End, It Went Back Bigger, When I Shattered Four Speeds, I Learned To Build 'em Better. I Built A Tunnel Ram For My Z11. The Power Kept Coming Up. I Went To Real Drag Slicks, And Whoaaaa, Nelly. The Car Dug In So Hard, You Would Almost Black Out From The G Force. Then I Learned (the Hard Way) About Spinning The Rims Inside The Tires. 7lbs Of Air. Guess What? It Cuts Off The Valve Stems. This Is Trouble At 135 Plus. The Car Wallowed All Over The Track, At Speed. The Car Would Leave So Hard That It Would Lift The Front Wheels Up In First And Second Gear. Remember Is Is A 409 In A 55 Chevy, In 1970, With A Teenager At The 4 Speed. The Side Walls Of A Drag Slick Are Designed To Allow The Tire To Flatten Across The Bottom, With Approx A 12"x12" Patch Of Rubber On The Ground, Using Super Soft Rubber. The Wrinkle Walls Keep That Much Patch On The Ground Even After The Car Starts. At Speed, The Centrifugal Force Makes Them Spin Round. Watch A Dragster Start And Then Go Thru The Top End. These New 20" Wheels Are Great For Cornering, But They Are So Round, That There Is No "patch" Of Rubber On The Ground. They Just Spin. Anyway Drag Slicks Are Essential.

 

[TurboTerry87gn]

Tires

I am using 28 inch tall tires, but yes the real reason for the 325 50 15 MT drag radials is the look.

I got the QA1's 12 way adj installed but I need to get back to the track so I can figure this thing out.
The old shocks in the rear are the KYB's.

You might be on to something with the air bags. My car initially hooks good as far as I can tell. It pulls the front D/S tire just barley. Anyways the car initially hooks then as the car rebounds back up in the rear. As the rear of the car reches maximum separation from the axle it seems as if it's pulling up on the rear axle and letting the weight off the rear tires. I can actually spool 20 psi @ 5000 rpm and the initial hook is there but I can feel the rear let loose and spin right after that. Thats why I bought the rear adjustable shocks so I could control the rebound and squat on the launch.

Now I just need to tig me a wolf race craft "style" sway bar to keep the rear level.

Here is something to ponder on:

On a mustang dyno dual roller with two eddy currents, set up for drag race mode, with all the friction coefficents and car weight plugged in to control the eddy currents, I launched the car at 20 psi @ 5000 rpm. The driver side front tire came off the dyno streaching the front straps as the dyno graph showed 1100 plus rear wheel TQ initially and tapering down to 900 at the end of first gear. I cut a 1.41 60 foot on the dyno and my 1/8 mile ET was 6.6 sec , thats within .1 sec of my real ET at the track. It was fun and scary all at the same time. My tires were pretty chewed up from the knurled rollers on the dyno.

 

[TurboTerry87gn]

I just got my QA1 12 way adjustable rear shocks in.

For thoes of you who are running these shocks what setting have you found be be the most succesful for you'r 60 foot times.

My set up:
Upper edelbrock adjustable arms
Lower Metco with instant center bracket installed
Competition engineering front adj shocks set at 70/30
Competition engineering rear drag springs
stock front springs
stock rear sway bar
No front sway bar
Air bags 11 psi D/S 17 psi P/S
MT ET streets no tubes 12.5 PSI on Weld drag lights 15 X 8 X 4.5 B.S.
Just installed QA1 12 way adj. (need to tune these soon)

Welds 15 X 10 X 5.5 B.S. with 325 50 15 MT ET street radials waiting for me to notch the frame.

Thanks for the info in advance.

 

[TurboTerry87gn]

Pics

Her are pics of my rear suspension set up and some other of projects I have done.

 

[MIB]

I am running HOTCHKIS lowers and uppers, H&R swaybar, no bags, KONI reds and 275/60 MT DR's. Nothing special on the setup. Car would 60's in the high 1.30's off the footbrake when I had the 200-4R and NLU AC 4000. I am installing a TH400 w/brake and ATI stall. I hope it leaves as well or better. What rear gears are you running?

 

[TurboTerry87gn]

Gears

I'm running the stock 3.42's with moser axles.

 

[MIB]

Okay, I am running a little bit more gear.

 

[Chuck Leeper]

"You might be on to something with the air bags. My car initially hooks good as far as I can tell. It pulls the front D/S tire just barley. Anyways the car initially hooks then as the car rebounds back up in the rear. As the rear of the car reches maximum separation from the axle it seems as if it's pulling up on the rear axle and letting the weight off the rear tires. I can actually spool 20 psi @ 5000 rpm and the initial hook is there but I can feel the rear let loose and spin right after that. Thats why I bought the rear adjustable shocks so I could control the rebound and squat on the launch".

The action of the shocks is likely being messed up, due to the spring rate changes incurred when the air bags are compressed. [That's a common problem w/ air shocks, and is essentially what you have.]
I had the same problem with that setup. Took the bags out, put new stock springs in, and an HR bar... Whamo! Leaves strait. A totally different car.

 

[Luke]

I am using 28 inch tall tires, but yes the real reason for the 325 50 15 MT drag radials is the look.

I got the QA1's 12 way adj installed but I need to get back to the track so I can figure this thing out.
The old shocks in the rear are the KYB's.

You might be on to something with the air bags. My car initially hooks good as far as I can tell. It pulls the front D/S tire just barley. Anyways the car initially hooks then as the car rebounds back up in the rear. As the rear of the car reches maximum separation from the axle it seems as if it's pulling up on the rear axle and letting the weight off the rear tires. I can actually spool 20 psi @ 5000 rpm and the initial hook is there but I can feel the rear let loose and spin right after that. Thats why I bought the rear adjustable shocks so I could control the rebound and squat on the launch.

Now I just need to tig me a wolf race craft "style" sway bar to keep the rear level.

Here is something to ponder on:

On a mustang dyno dual roller with two eddy currents, set up for drag race mode, with all the friction coefficents and car weight plugged in to control the eddy currents, I launched the car at 20 psi @ 5000 rpm. The driver side front tire came off the dyno streaching the front straps as the dyno graph showed 1100 plus rear wheel TQ initially and tapering down to 900 at the end of first gear. I cut a 1.41 60 foot on the dyno and my 1/8 mile ET was 6.6 sec , thats within .1 sec of my real ET at the track. It was fun and scary all at the same time. My tires were pretty chewed up from the knurled rollers on the dyno.

Those Competition engineering / Moroso Trick springs are supposed to have a softer drivers side, which supposedly eliminates the need for air bags. I'd avoid making more than one change at a time so see what you can do with the QA1s. If it still doesn't hook right, just pull out the bags and give it a try. Not only is this an easy thing to try, it's FREE! The worst that could happen is that it hooks less and you have to put them back in. Let me know how the QA1s Fair. Good luck getting that suspension dialed in.

-Luke-

 

[ttypewhite]

Wolfe bar, drag shocks, metco lowers & adjustable uppers on MT 28"x10.5" slicks gives me 1.37 sixty foots. Your only going to get low 1.4 to high 1.3's if you launch at 20psi. Launching at 10psi off the footbrake I get 1.48 sixty foots with my slicks.
Get rid of the air bags and install the Wolfe bar/ HR bar and your good to go. My springs are stock OEM replacements. Did your aftermarket shock lower the car any over stock? You might be stopping the car from sqwatting properly if its not dipping down enough with a shorter spring. Might also want to look at your converter for slipage. May need to be tightened up.

 

[TurboTerry87gn]

Rear sway bar

I appreciate all the help. I really try to get all my issues worked out on my own or by reading older posts, so thanks again.:biggrin:

Thinking about the whole thing now it seems like the 2 main parts needed for the rear suspension is a good sway bar and good shocks.

It now seems like the air bags are a quick fix for the real parts needed.

Time will tell, I will report back after some track time so others can learn from this post and not waste money like myself. I will try the old original springs with and without air bags at many diffrent shock setting.

 

[johnplogii]

I had really bad luck with m/t et street bias ply's. I ran 28 x 12.50 x 16 which is 10 in wide & never could get it to 60ft good. My best was a 1.59 and it seems our cars run pretty close. I switched to hoosier slicks & got low 1.50's with a 1.48 or 1.49 occasionally. It still is not right & I think it is partly due to running a 10 in wide tire on an 8 in rim. I will be switching to a 10 in wide 15 in rim here shortly. I agree about the springs, either run the drag springs with no bags or stock springs with air bags, not both.

 

[Mr.Spool]

turboterry,if you can initially hit the tire with a 10lbs get out alittle then feel the suspension unload your bags have to much air,if right upon leaving it grabs then breaks them loose the converter may be shocking the tires,what converter and stall are you using?i have run both bfg and mt 325 drag radials,unnotched and on an 8 inch rim with sway bar in the bfg went 1.58 60 on 1lb launch on a protorque 10 inch lockup went 1.67 60 on a 12inch.the 12inch liked to shock the tires the 10 inch didn't the 12 felt faster but the slip said differently.i wouldn't throw any more parts at the car,if the car keeps unloading i would try to isolate the issue, could be the spool of the turbo,the converter,all of which the suspension feels.i have not gone after the mt 325's at the track so i have no hooking comparison yet,but you can't hit the drags as hard as the bias plys

 

[TurboTerry87gn]

Testing

I'm using a PTC 9" converter with the TH400. It flashes to about 3000 rpm and will stall @ 5000 under high load 20+ psi.

I took the car out tonight with the new shocks to how they would respond on the street.

At 12.5 Psi on the MT 28x11.5x15 @ 12.5 psi air bags delfated and Qa1's set to DS: 2 ,PS: 3 I could hook upto 6 psi on the foot brake.

I'm going to the track tomorrow to work only on the 60 foot times. I will post the results tomorrow.

 

[11secondgs]

I know folks hate the ssm lift bars, but if you use the ssm lift bars with the brackets welded in and uadjustable uppers, your car will hook well.

Do this, go find some slick back country road and adjust your suspension to hook as good as possible there, something around a -4* pinion angle, and then when you get to the track, you will just smoke the 60's in the 1.45-1.48 range.

Transbrakes, plus slicks are also musts to propel these cars forward fast. These cars are light in the front end, and have the motor shoved so far backinto the firewall, that there is no reason not to be in the 1.45 range with slicks and a hard launch.

The ssm bars tear these cars apart because they really do work. Just reinforce them where appropriate and use adjustable uppers. There is more than one way to skin a cat, but this works for me more consistantly than other tricks with airbags and crap. I have a lowered car with regular springs, nothing fancy.

 

[ChavoLC2]

To squat or not to squat

Quoting a gentleman named Mike Canter of Outlaw Pro-Mod fame. The article was about video taping in "Slow Motion."

There is a standard progression of events that occur as a doorslammer launches- watching these events occur gives you the clues to dialing in your suspension. "The KEY is to have these events happen at the right TIME is your shock valving control.

This should be the sequence of events as seen on "Slo-Mo video".

1) Right at launch the front should start to rise up before any forward movement.

2) The rear of the car with the added weight transfered, from the rising front will lift very little but "should not go down(squat)" an inch or two is normal and can be seen by the relationship of the top of the SLICKS to rear fender lip.

3) This one or two inches will indicate that the rear of the car is lifting and pushing down harder on slicks/tires while the front weight is being transferred(for every motion there is an equal or opposite motion)

4) If the front of the car does not rise then the front shocks are to stiff.

5) If the rear squats right away then the rear shocks are too loose.

6) I found that thru slow mo videotapping if the rear shocks are too loose the rear tire actually bounces on the initial hit and will break loose right away, I stood next to car pointing camera at rear tire it was amazing to watch, I kept on tightning rear shocks till it stopped which was right below midpoint of the adjustment.

From all that I have seen that the rear shocks should never be adjusted below midway point because of squat and tire bounce.

 

[TurboTerry87gn]

Shocks

Thanks for the info on the shocks. I haven't had much sucess getting to the track and running.

Unfortunatly I can only make it to the hot street nights on Sundays when the prep isn't optimal but it seems like ever thing is working aginst me on the shock tuning thing. I left for the track last Sunday, get in the gates and as I make the turn around the other side of the track I see a thunder cloud over the horizon. I hurry and set my tire pressure, let all the air out of my bags and set the shocks for zero as I'm planning on an easy 5 psi launch. The guy next to me comments on my car and asks if I'm going to run today. I reply yes and hopefully before it starts to rain. He comments, well the weather said it wasn't going to rain today as I look at him and then to the clouds. No more talking its nearing 5 pm and the track should be open for cars soon. I pull in the staging lanes a flag down a tech to put numbers on my car, as I hear the announcer say the track prep will be ready in about 15 minuits. I'm thinking it's 5 pm and the track should be ready, the clouds speed ahead. The announcer tells all the track is ready. Before he finished his sensence the sprinkles start and before long it's raining heavily. I go to the food concessions and get a bite to eat as I wait it out along with every one else. About 15 min later the rain stops and the clouds are gone. Clear sky! I look over and I see the young girl that served me walking to her car with a back pack. I look over at the announcer stand and its windows curtains are closed. The annoucer didn't even say he was shutting the track down and all the staff just up and left, even the poeple at the ticket booth. By the time I left, the staging lanes were dry and the roads were too. But now I've wasted my time and I've been SHAFTED out of my money.

I'll get to the track one day and I will post my results as I've methodically prepped a log sheet for the suspension changes for the bags and the shocks vs boost while staged and track 60' times. with my same 12.5 psi tire pressure.