IHADAV8.com - Turbo Buick Tech, and Nonsense
Tech Area => General Buick Tech => Topic started by: trashmechlv on June 29 2013, 08:58:27 PM
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I was trying to get an idea of what people are running for a rear suspension setup and what tires? The reason I ask is because I took my GN to track last night here in Vegas. First of all it was record heat and still about 105 degrees at 9pm start. I could not hook up car at all with horrible 2.50 60fts. The only reason I even tried to run with the excessive heat was its the last test n tune here until end of summer and I recently bought my car and did some work on it.
My rear suspension is all stock and rear bushings visually look ok. Front susp looks like it has a fairly recent rebuild. Im running 275/60/15 Nittos on stock rims. I started at 24psi in tires and gradually dropped pressure eventually ending at 17psi with traction getting worse. I did burnouts until I saw smoke. I left the line from 10lbs boost down to idle and just roasted tires, had to pedal car a few times. Also felt tires spinning about 1/2 track with car squirrely.
Looking for some setup ideas that work well with low 60ft times. My car is stock eng internals, Precision TE44, 3 inch downpipe, stainless headers, stock IC, Precision 65lb injectors and 100 octane chip from TT. running 21lbs boost. Stock 8.5 posi rear. PTC 10" 2800-3000 non lockup stall. I just installed PTC stall after having a sorry 12" non stock converter in car. Went from building no boost and leaving like a turd to instant boost and shredding tires. Ive owned many cars and have made lots of passes on the track in the past but haven't had a car making this much power coming on so hard with the turbo. I felt like a rookie out there. Runs were similar with 2.50 60ft and 13.90s at 101mph. I believe this car has 12s in it with a good 1.60 or 1.70 60ft time. Maybe just need slicks or better drag radials? Thanks for input. It was fun running down Mustangs with 2 second head starts with the back of my car skating around.
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28x9 slicks
70/30 shocks up front-50/50 rears
ATR rear sway bar
1.6 foot brake launches
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Thanks, what boost do you launch at?
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I come off the footbrake at 2800 RPM.
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315/35R17 Nitto NT05R Drag Radials
Auto-X/Road race type suspension
1.7 60'
11.9 @ 112mph
Timeslip is at the end of the video:
1191at112mph (http://www.youtube.com/watch?v=kMS3KWwIovg#ws)
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I'm gonna start a little differently than most would. Have you had the car up on a lift so you can check all the bushings? If not I'd do that before you even consider doing any suspension mods. This may be related to the tires and heat or it could be suspension related.with the temps you're seeing out in Vegas right now I would expect the track surface to be well over 120 so it would be a bit slippery.
Since the tracks out there are going to be closed due to heat soon I'd say do some reading up on good set ups and once you get one scale the car to see where the weights sit. You'll be surprised where the weight is sitting. :cheers:
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Part # or Keyword
I run this it fixed my 60 ft
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well that did not work
I added a Hellwig Pro touring #55809 fixed my 60
I have UMI rear bars the new bushings was nice +for the ride but was no help in the 60ft
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As Charlie mentioned, the track was way too hot to make it easy to get traction. I suspect there were a lot of others out there complaining because they were not hooking. Also, you are running Nitto's and they are a great drag radial for the street but they are not so good at the track if for no other reason than they use a much harder rubber compound and they just don't hook as well as M/T, M&H, or Hoosiers. I run the same Nittos as you on both of my cars and they do pretty good on moderate days on the street but when the temps hit a hundred, they spin instead of bite. It does not help any that you are running them on the stock wheels which are a bit narrow and make them a little squirrelier as the tire pressure comes down. Nittos are great street tires, last much longer, and are not absolute suicide if you ever see rain.
I suggest you find a set of 8" wheels with 4.5" back spacing and add a pair of of the above mentioned dr's to them. Note that some of the above brands specifically say NO street driving on them.
As Tim mentioned, the Hellwig bar works very well to equalize traction between the two rear tires. It is light weight compared to the solid 1 1/8" bars that so many of us run, and geometrically is similar to the much more expensive H&R bar which works better than the factory style mount. It is nearly impossible to launch a car with more power than stock without a good rear bar.
Next, you have to be certain that the bushings are good as mentioned above. If for no other reason to be sure the car launches the same way each time and does not try to change lanes on you. Be sure the front control arm bushings are good (particularly the upper passenger side at the rear under the down pipe)-and ball joints for sure. A car that goes crooked on launch will probably try to do the same when you lift at 120.
Having boxed lower rear arms can help as well.
Be sure your limited slip rear end is actually working properly! Find some clean pavement, load the converter, and do a strip type launch. Get out and look at the stripes. They should be pretty much equal in length as an indication the rear is working. Then look at each stripe for eveness of "blackness" across the laid down patch of rubber. If the stripe is blacker in the middle than on the edges, you have too much air in the tire. If the stripe is blacker on the outside than the inside, you don't have enough. Play with the air pressure until you get the most consistent stripe.
You should not need air bags on the average car.
With regard to shocks, I think stock shocks on a car that is a daily driver is the way to go. You never know when you may have to swerve hard to miss an air plane landing on the stripe or such. If you can find one of the tubular front sway bars, put it on the car. Never hurts to lose a little weight up front.
I don't know what your converter is actually stalling at, but, I have found about 2700 rpm and around 5-6# of boost is a pretty good beginning launch point for a TE44 until you prove that your tires will stick under the given track conditions at a higher boost.
Sometimes, things are so bad that you may have to use the chip to detune the car a bit in order to keep from spinning up in second gear. Those are the days that you might be better off at home in front of the AC and TV.
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Can't argue with that.
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Thank you for all the input everyone. Steve, I have read most of your info on your website dealing with these cars and it is very helpful. I also think a lot of it was the crazy temps, track temp was probably super hot baking in 117 all day. I will look into a better rear sway bar and give closer inspection to the bushings. I can box my lower arms myself if that helps. I am kicking myself for trying to save a few bucks by buying the Nittos since they cost less and would last longer. :013: Do the MT drag radials hook that much better than Nittos? Searching on the forums I have seen people cutting good 60fts on Nittos. I would just buy slicks but have a 22 mile drive to and from track mostly all highway and don't have a car trailer. I may not have anybody go to track with me that could bring my slicks for me. The car is not a daily driver so I shouldn't have been so worried about tire wear. At least I have all summer to sort it out, not going to attempt running again until well into Sept or Oct when temps drop.
Mike
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M/T's will consistently hook better at the strip under a wider variety of conditions. They are much softer and therefore, more sticky. Most drag radials do not like a hard burnout...just enough to warm the surface. Most of the tire companies have some comments as to how they think they work the best on their sites.
They don't handle as well in street driving. I like the Nittos, but, then, I don't go to the track anymore.
I have not been impressed by slicks on these cars unless one is a lot faster than 99% of us.
I need to rewrite the suspension part of the page and get more inline with my current thoughts.
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/me stands by to update...
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M/T's will consistently hook better at the strip under a wider variety of conditions. They are much softer and therefore, more sticky. Most drag radials do not like a hard burnout...just enough to warm the surface. Most of the tire companies have some comments as to how they think they work the best on their sites.
They don't handle as well in street driving. I like the Nittos, but, then, I don't go to the track anymore.
I have not been impressed by slicks on these cars unless one is a lot faster than 99% of us.
I need to rewrite the suspension part of the page and get more inline with my current thoughts.
I will argue that my NT05Rs handle pretty well for a drag radial. Being low profile helps. My M&H DragMasters = wobble city by comparison.
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So is their a big difference in all the available aftermarket rear sway bars? I see a wide range of pricing. Is a 1" rear bar good or should it be larger? Saw a Spohn 1" bar for $174. Hellwig bar around $200ish. Sounds like this would be a good investment since my car has stock rear bar on it.
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I believe the ATR bar that we used so many years as the "trick" bar for drag racing was/is actually 1 3/8" rather than 1 1/8" as I said earlier
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So is their a big difference in all the available aftermarket rear sway bars? I see a wide range of pricing. Is a 1" rear bar good or should it be larger? Saw a Spohn 1" bar for $174. Hellwig bar around $200ish. Sounds like this would be a good investment since my car has stock rear bar on it.
I think the Hellwig is the best of the lot. Look around for a good price because it is often one of the cheaper ones
$201 on amazon with free two day shipping if you have a Prime account. It's adjustable so you can use the shortest arm location for the stiffest affect. It's a lot lighter which is worth something as well. I think one of the old ATR bars would trap me if I got caught under it these days
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I love my Hellwig Pro-Touring bar.
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I have 5857 and run 11.9 with 1.7 60 using 9X28 slick I change at the track
I loved my MT but our track prep is so bad the 1/2 up shift I was out of the DHT and all over the track.
The slicks fix that but I dont like the !00mph wobble ,It manageable
I run the Hellwig made my 60 ft consistent.I run it in the middle hole
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315/35R17 Nitto NT05R Drag Radials
Auto-X/Road race type suspension
1.7 60'
11.9 @ 112mph
Timeslip is at the end of the video:
1191at112mph (http://www.youtube.com/watch?v=kMS3KWwIovg#ws)
What pressure do you run your Nittos at the track? I have the Nitto NT555R drag radials so not sure the difference between the two. I believe I will be getting the Hellwig Bar for the rear soon. I would like to get my tires to hook since I just bought them and don't want to shell out more $$$$$ for some M/T drag radials or slicks with extra rims. Nice pass in your video!
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I used to run around 18 but pressure depends on the track and ambient conditions. I told you above how to look at the tire patch and adjust the pressure
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Same here... but it took some testing. Follow the procedure Steve gave you and you'll be in the ballpark; season to taste.
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ordered the Hellwig bar from Amazon for $201 shipped. Best price I could find online. Will check my bushings and probably box my lower control arms. After that I will figure out my tire psi and hopefully hook up in the fall when the heat breaks. Going to try to stick with the Nittos (pun intended). Thanks for everyones input. This site is a lot of help.
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If you learn to drive it, you should be within about 3 tenths of the better tires on the top end.
the sway bar should help a lot
You need to look at your scan tool data and see why you only turned 101 mp. It should be closer to 115. Perhaps the heat killed the air and it was running really rich, or you lifted way earlier. Hard to say without some data
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If the track was that hot he may have been loosing mph due to traction Steve. Seen that before here. :013:
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I'll take a shot at valve springs have gone south.
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You need to look at your scan tool data and see why you only turned 101 mp. It should be closer to 115. Perhaps the heat killed the air and it was running really rich, or you lifted way earlier. Hard to say without some data
Like I said :)
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I did go at it wrong when I went to track. I was rushing to get out there since it was last TnT until end of August. It was WAY to hot that night (well over 100 at 9pm). I slapped my new PTC converter in car Thursday and straight to track Friday night with no drive time. Actually only put a few miles on car since I got it in April since Ive been doing work to it. When I made passes I should have made notes of my Scanmaster data after each pass, but only checked for knock after each pass. Im guessing engine has the original valve springs. My tire spin was bad through first and started up again in second gear. I actually had to pedal car through 60ft. So I believe its a combo of the heat, tire spin and my tune. Im still learning the ropes of tuning this car. Thanks for the support from you guys and next trip to the track in the fall will be better all the way around!
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Valve springs were usually worn out by the time the car hit 50k miles and time also plays a major factor. You can usually tell because the car does not want to accelerate past 4000 rpm or so...not quickly at all.
It takes time to sort them out and to understand how all the pieces of the puzzle go together. Save some money for Power Logger because it is invaluable in sorting out a car in just a few passes and makes it easier for others to look at your data and help you. :}
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Was trying the burnout test for even strips. They are even in legnth and darkness across but.....it looks like I get alot of wheel hop???? I have the hellwig bar, boxed lower arms and poly bushings. What can I do to stop the hop?
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Hopefully it is not the poly bushings binding up...which holes did you use on the sway bar? shortest ones? If so, try the middle ones
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Middle ones
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Get rid of the poly bushings. There's supposed to be some flex in the rear suspension and poly bushings don't allow for it. :sw:
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Get rid of the poly bushings. There's supposed to be some flex in the rear suspension and poly bushings don't allow for it. :sw:
No kidding! it was a bitch to install these in the top arms. I thought these poly bushings were supposed to be the cats ass?
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Cats asses don't work well for rear suspension pieces. did a vendor tell you that was what you needed? the rear bars do not rotate on a common center so they tend to bind if the bushings do not allow for some movement.
Then try putting the sway bar links in the shortest holes to increase the load on the tires on side to side movements and see if that helps.
IF not, put the stock lowers back on...do one at a time and it should not be a hard job unless fighting rusted up bolts
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BTW, don't you have those donk like tires on the back? They might make the problem worse?
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Poly bushings are great, if you plan on going to a road course. For a drag strip Steve's right, they cause the rear arms to bind rather than work properly. If you just want to see a simple difference, loosen the bolts that hold the arms in place just enough to let the arms move. It will make some noise but try doing a light launch on the street and you'll see a big difference. :icon_lol:
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for a road course that need the rear to articulate the poly can and does restrict articulating movement compared to the softer stock bushings.
for drag strip polys work , they dont bind for what they need to do which is travel up and down evenly . the poly centers are free to rotate where the stock bushings only rotate by twisting the rubber (unless you loosen the bolts)
problem with stock is the amount of compression they just dont cut it when the hp gets higher , i split the poly pop in bushings in the umi rear lower control arms. the energy suspsenion bushings are better.
on the rear i now run heim end uppers and lowers (wolfe racecraft) , and wolfe pivot bushings in the rear axle ears
they have no bind and wont compress so i can set my pinion angle close to zero degree and it will not move from there, poly can move as much as 4 degrees and stock bushing more than 6 degrees
for rear sway bar i run the hrpartsnstuff HD rear bar which has heim end links
for the front the stock bushings are serrated and restrict travel since the rubber is bound to the center tube and the outer shell (thats why you have to tighten them when they are at ride height ) , polys dont restrict movement up and down because neither the center tube or the shell are bound to the rubber.
to lessen the stock bushing restriction you can loosen the nuts at end of upper control arm and loosen the bolts on the lowers
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I have the Energy Suspension bushings all the way around on the car. With the bolts tight, the center metal tube locks in but the poly bushing can rotate freely when the arm travels up and down? I can try moving the sway bar to the shortest hole. For tires I have 17 inch wheels but the tires are the same height as stock tires were. I measured at the time so they would be the same but dont remember what the number was now.