suspension mods for <1.40 60 ft.

[bragggf]

trying to get an '87 GN setup to 60ft in the 1.30-1.40 range on a 10.80 ET using slicks or DOT's. Car currently is in the 11.50 range with 1.65-1.75 60fts on 275x50 drag radials. car is not just a drag car so want decent manners on the street and will be keeping a sway bar on the front. also doing some perf. mod's to improve mph to the 120+ range.

currently setup is very basic
1. drag radials
2. air bag
3. pinion snubber
4. rest of suspension is stock original (shocks/springs/etc.)
5. can launch at max 5-7lbs boost.

have been reviewing posts and have the following parts list

1. boxed control arms
-- adjustable or relocate per Kevin's recommendation?
2. qa1 (formerly hal) adjustable shocks
3. larger rear sway bar (ATR?)
4. line lock (no trans "break" for me).
5. larger rear brake cylinder's.
6. aluminum (TR) brake drums
7. lightweight rims/Mickey Thompson slicks (either drag ET or ET streets).
8. aluminum driveshaft (most don't do this, why?)
9. stiffer progressive rate rear springs (which brand? do I bother lowering (don't think so)).

anything missed from above? have following questions:
1. adjustable control arms or relocate? which is the preferred brand?
2. best tire I can use and still drive to the track?
3. spring recommendations to help launch and street manners.
4. is it typically necessary to relocate the control arms to improve launching characteristics on a stock height car (not lowered)?
5. what setup are others using to 60ft in the 1.35-.140 range on a 3700lb car?

Thanks for any info/replies. can also email me at gerry.bragg@altarum.org.

 

[NastyGn]

I think what you are wanting is the 60' of a race car and also good street manners.

This is a tough act to follow because what I think you will end up with is a car that does neither very well. Your goal of 1.3 to 1.4 60' may be a little high for what you want. I think a 1.5 to a mid 1.4 may be possible with somewhat good street manners but a 1.3 I think maybe a little far.

I see you want to keep the front sway bar, this will limit how high the front end comes up (this is weight transfer to the rear wheels)
you might be able to loosen it up or get a hollow one (lighter) but it will still limit how much weight is transfered to the rear wheels.

As far as adjustable control arms there are a number of good ones IMOP, Paul makes some nice ones, Metco also makes some nice ones. You will want the ones with the extender plate that lowers the mounting point under the axle. This will raise the Instance Center of the car allowing weight to transfer to the rear easier. The adjustable uppers allow you to set the pinion angle better (IMOP) and the preload.

The bigger rear sway bar helps a whole bunch for body roll and will help keep both tires planted.

Overall I'm sure there are as many ways to set up the suspension as there are people on this board and if I understand what you posted I don't think you will be able to get what you want. This will also depend on how much of what you call street manners you are willing to give up VS a good 60'

Take Care

 

[Chris McDade]

It's not just the supension that's going to get you the best 60 foot times. Your turbo and converter combo is also whats going to give you the best 60 ft times. To go low 1.4 or high 1.3 your going to need a loose converter i.e 4000 stall or higher and thats not going to be very streetable. Or a trans brake. What Neal said , plus the right turbo and converter combo will get you the best 60ft times.

Good Luck.

 

[Chuck Leeper]

Suspension ideas??

Several items come to mind when looking to get your targets met.
1. Lose the snubber. It only serves to mess up the suspension travel and adds unwanted bind when in contact w/ the chassis.
2. You will not get the desired 1.30, or most likely the low 1.40 w/ street tires. Slicks are recommended. BTDT.
3. As others have said, it's going to be necessary to have a looser converter than you may want for street use.
4. W/out a trans brake, the target will be much harder to achieve.
5. Lose the alum drums. They are OLD and have been commonly known to crack, especially w/ hi brake pressures need to launch w/out a t-brake.
6. Shocks and springs play a pivital role in tuning for those short times. Adj shocks help alot. When in the short times discussed, you will be much better to use an antiroll bar than try to tune air bags.BTDT too!
7. The pinion angle is of limited importance and is not used to tune a suspension other than to eliminate binding of the joints. Pinion angle will not be held unless you have good suspension bushings and reinforced or aftermkt control arms.

Enough HP to run in the 120 range will not be high enough to get a 1.30 short time. These are approximate segment times, using the terminal speed and Et for a car that is properly tuned and suspended.
123.5mph/10.75, 1/8-6.81, 330-4.36, 60-1.46. Going 1 step further, the short time at 1.37 gives the following results:
134.5mph/10.00, 1/8-6.33, 330-4.06, 60-1.37.
As you can see, by looking at the MPH, the HP required to put a 3700# car into the 1.30's or even the 1.4's is considerable. There are math equations you can use to determine where you'll have to be HP wise to accomplish this.
HTH,

 

[azgn]

what Chuck said...your goals are not consistent with what you are intending to do..

a high 1.4 can be had at 122 or so, but with slicks and a high boost trans brake launch...also drag shocks, no front sway bar, and a well set up suspension (new springs, shocks, boxed control arms, large rear bar, bushings,etc etc)

to run 1.3/4 without t-brake would require a car that makes enough power to go 135 in the 1/4 (9.x) and even then it is doubtful

the kind of 60' times you are talking about do not happen on a "street" car...you need lots of power, traction, and high boost launch...the car is still "streetable" but with compromises in the ride area.......(Granma would not like riding in my car....)

 

[Quickturbosix]

These guys all have you one the right track.

One thing that is missing is axles. 1.3/.4 short times will kill the stockers in no time. Of course longer wheel studs will be needed too.

Not that they will make you any faster...but faster longer.

 

[tom h]

no experience here, but videos of TRs with the Wolfe design sway bar seem to launch incredibly straight, with much less twisting and body roll. I suspect it has to be combined with a roll cage for maximum benefit. How beneficial in "real life" is something like the Wolfe swaybar??

http://www.wolferacecraft.com/pages/buick parts/buicksway.htm

 

[JDD]

One other thing to consider,you will be working on your 2004r alot more at these levels.Jim

 

[S2V6RACER]

These guys hit the nail on the head. Take my times for instance. I'm launching on a t-brake at 4500RPM at 12psi. The 1.3's I ran are not easy to do and traction must be there. I am running a spool, 9" with 35 spline axles and have a ladder bar rear suspension. This is a race car, and it isn't pleasant to drive on the street unless the road is smooth.

Trying new torque convertor, so I'll be testing the old convertor/turbo theory as stated above.

 

[bragggf]

thans! few more questions

great info! appreciate all of the replies. so, sounds like I should be happy dipping below 1.5s.

some folks mentioned "Pauls'" or "Metco's" adjustable control arms. appreciate any more info on how to obtain or get more info on what works in this area.

should I still look at axles if running in the 1.45-1.50+ range?

the trans has been built and hope not using a t-brake will make
it last longer.

3200 stall converter; PTE-52 turbo, front mount, houston dp, etc...

am I missing anything on my parts list? Gather I lose the pinion snubber and keep the stock cast iron drums

thanks!!!

 

[azgn]

well, if by chance, you get into the 1.5's (which I doubt without a brake or a bunch more hp) you could use some better axles....I have 30 spline Mosers and Eaton posi with Ford ends (eliminates the c-clips which is required by NHRA if you go faster than 11.00)

Paul Ferry (HRParts) and Metco can both be found on the net....Paul advertises on this board...any old search engine should find 'em....they both make suspension components for G-body cars as do several other companies (like Hotchkis)

 

[1QuickV6]

Originally posted by tom h
no experience here, but videos of TRs with the Wolfe design sway bar seem to launch incredibly straight, with much less twisting and body roll. I suspect it has to be combined with a roll cage for maximum benefit. How beneficial in "real life" is something like the Wolfe swaybar??

http://www.wolferacecraft.com/pages/buick parts/buicksway.htm

The Wolfe bar is awesome, on the street and at the track, but in this scenario that car won't touch 1.3/1.4s no matter what. Compromises need to be made, of course, to achieve those times no matter what setup you prefer. I've had the good fortune to be one of the first to use the Wolfe bar, and have it dialed in about as best as can be on my car. Still, on a 10.28 pass (and subsequent 10.40- 10.50 passes), I can't muster anything better than a 1.45 60'. I have decided to not alter anything in the setup (like going to 90/10 fornt shocks, changing the stock axles, changing gears, going to a TB, etc...) for fear of "ruining" things and having to start the search all over again for that good launch.
Best of luck getting those 60's down! There are many proven ways to do it, as you have noticed.
Take care,
Erik

 

[Nick Micale]

Re: thans! few more questions

Originally posted by bragggf
great info! appreciate all of the replies. so, sounds like I should be happy dipping below 1.5s. .......
........the trans has been built and hope not using a t-brake will make it last longer.

You should be happy to get into the 1.6's! All the replies here are seasoned drivers that have LOTS of time, effort and $$$ in their cars.

With no transbrake, you will have a difficult time with consistant, good launches. The reason you give is the trans will last longer has no basis in fact. Woody, and many others, have hundreds of launches with a TB on the 200-4R. The major strength problem of this trans is not at launch, but when you have a WOT 2-3 shift and the drum shears or clutches give out.

Good luck, remember, it will take time for you and your car to get "dialed in"!

 

[HRpartsNstuff]

Wow, a lot of good advice here!

Just to agree on a few points first:

Ditch the snubbers, they just unload the suspension when they hit.
Air bags (with our spacers) will work good, and combined with a "wolfe style" anti-roll setup would be best. We are working on a bolt-in kit that works on the street right now. You can drive the other brands on the street too, but not a true "street" setup. I wouldn't go road racing with one on the car, which I assume you like by keeping the front swaybar.
Definitely need axles. Don't try a 1.4-anything without them. You don't want to break one, it makes a mess! Not to sound like an info-mercial, but we carry Moser stuff now but we don't have it on the website yet, but you can just call if interested.

As for my recommendations, here goes from a street driven 10.70's car at 125mph, with a 1.40 60 ft. and other info I have learned along the way:

Mid to Low 1.5's are the norm for high 10 sec cars. To go in the 1.4's, you have to step on it hard. You can't baby it off the line at 5-7 psi & expect any kind of results. I launched off the foot brake at 20+ psi every time. Just one word, FUN! You need a well balanced combo to do that. I tried a front mount IC, but went just as fast with the CAS V-4 (which we carry now too ). I highly recommend the stk locn IC's over a frontmount (except total race cars) because they spool up faster. The faster the spoolup, the higher the stall, and the more power off the line. Your turbo, chip, tune, etc have to be on too, or it won't spoolup fast either. I got 3600+ out of my 3000/3200 converter. I ran a 4000 stall & got 4600 out of it, which was out of balance. It came off the line a little harder, but just rpm'd the whole way for nothing. Mde it worse on the street too, I really liked the 3200 for street/strip. Our rear control arms helped me out a bunch too. They are setup for good handling characteristics, and move very freely up & down. This allows the car to plant the tires quickly, and transfer more weight quicker. This in turn allows you to hit it harder & still hookup. Hitting it harder allows more weight to transfer, getting more traction.... (you see where this is going). If the car bounces off the initial start, then our airbag spacers will help. They allow you to run less pressure & get the same downforce. This takes the "bounce" out of the rear & keeps it hooked up, allowing more weight to transfer.... (here we go again). It all has to work together, and allow the weight to transfer quickly. Your adj shocks up front will help. Plus, lighten the front up all you can. Rims, tires, hollow swaybar, no swaybar, take stuff off, alum heads, etc... I don't believe in the bracket that lower the rear control arm mounting points either. In theory they are great, but there are some flaws when it gets put to use. You can't hit it as hard off the line with that setup, because it will wheelie higher than anyone would like to go Initially, at lower boost levels, it might help. But if you don't get the rpm's & boost up, it won't "follow thru" & get as good 60 & 330 ft times. Also, those mounting plates reduce the surface area of poly in the ends of the control arms, because they weld/bolt inside the original brackets. This lets the center bushing push thru the poly, and hits metal to metal. I've seen this happen more than once using these relocating brackets. If everything is working right & together, the stock locn mounting points work just fine, especially street/strip. The worse thing about these brackets is they make the car react VERY weird under braking! With race shocks included, it is a very weary "dance" at 125mph that I really don't like. Not my idea of good street characteristics.

Hope that wasn't too long & helped out. Let me know if I can answer anything for you or help more. Low 1.5's are very respectable 60 ft's for low 11/high 10's. 1.4's are always better, but it mainly comes down to how hard you plan to launch it. The combo can still be very streetable & do it, unless you choose to build it with parts that make it more of a race car. Oh yeah, adj uppers are not used for tuning (exactly). They can help a little, but once they are set, leave them be. Stick with weight reduction & fast spoolup, & quick reacting rear suspension & it will get there for you. Alum drive shaft will help a little there, but nothing huge. It all adds up though. Put your $$$ towards where it will do the most good.

 

[alilol6]

"I have decided to not alter anything in the setup (like going to 90/10 fornt shocks, changing the stock axles, changing gears, going to a TB, etc...) for fear of "ruining" things"

I'd be more worried about "ruining" my car running those 60' times with the stock axles. What could changing axles to something safer possibly do to alter your times???

Not changing axles is just plain foolish, IMHO. Besides, I thought it was a requirement to lose the C-clips at 11.00 and faster?

I just gotta laugh at someone who puts a Wolfe bar on his car and won't spend the time or money to upgrade axles.

Hope everything holds together for you, Erik

 

[1QuickV6]

Not changing axles is just plain foolish, IMHO. Besides, I thought it was a requirement to lose the C-clips at 11.00 and faster?

I just gotta laugh at someone who puts a Wolfe bar on his car and won't spend the time or money to upgrade axles.

Hope everything holds together for you, Erik

who pissed in your cheerios, dude?
laugh. i'm not touching a thing.

 

[turbov6joe]

You could always try the old Lonnie Diers method of launching.....let off the brake when the boost indicator stops moving I did about all of the things you and the others mentioned and really didn't enjoy driving the car on the street. I pulled low 1.5x's on a 10 psi launch and ran in the high 10's on a good track. Tell ya what, the first time you get a low 1.5x, you'll have a grin from ear-to-ear!

 

[alilol6]

Definitely need axles. Don't try a 1.4-anything without them. You don't want to break one, it makes a mess!

One thing that is missing is axles. 1.3/.4 short times will kill the stockers in no time.

Not to mention you could kill yourself or someone else with your stubborness/stupidity, Erik.


??

 

[HRpartsNstuff]

Originally posted by 1QuickV6


who pissed in your cheerios, dude?
laugh. i'm not touching a thing.

I don't think anyone is trying to wet down your breakfast cereal here, just trying to possibly save your life! At low 10's & 1.45 60 ft's, you are taking a huge risk of hurting yourself & possible someone else. I have seen quite a few break at low 11's, let alone low 10's. It sure won't effect your time slip by installing aftermarket axles. So many people hop up the motor, etc., without looking at the safety stuff. And when you are talking about a couple hundred dollars for axles VS blowing your rearend up, destroying your rear 1/4 panel, destroying a slick, and if it happens at speed... crashing your car, possibly taking out your competitor's car, taking out spectators, etc. You have been extremely lucky so far, but metal can be fatigued only so much for so long before it breaks. Your axles are way past the normal breaking point.

Hope you don't take that as pooping on your wheaties, we are just concerned. If I pulled up next to you in the final round & knew you had the stock axles, I would let you do a bye run. It ain't worth all that. Actually, I would sand bag the dial in & get & stay out in front of you & break out
Be safe-

 

[alilol6]

TTT...for our friend 1QuickV6