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#1
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![]() Your tires are a HUGE factor in handling,( obviously your only connection to the road.) Wider, stickier, premium casing construction and profile... and appropriate air pressures. Controlling forces on them of fore, aft, lateral weight transfer, and their attack angle to the road is how you make them work harder FOR you. Center of gravity height, front vs rear roll resistance and weight transfer amount and timing is how you make the have more traction and use all 4 tires. Overloading a tire makes it lose traction....fast. A stiff chassis is less forgiving ( has a smaller sweet spot when balancing handling)....but responds to smaller swings at adjustments. So, for a street driven car where you still want ride quality, you compromise. Aluminum heads and intake, moving battery to lowest area in trunk will both lower center of gravity height...and add needed rear weight. Good stuff. The front end alignment and geometry are VERY important details. Factory alignments and geometry are designed to give you a bad feel, understeer/push the nose... so average driver doesn't overdrive the car, past the limits of traction of the tires. An appropriate centerlink and ride heights will make for no toe in when turning and minimal bump steer. Aftermarket Spindles with optimized geometry. Appropriately valved shocks to control weight transfer timing. The hard and "more" expensive stuff. The cheap stuff: Lower center of gravity height, raise front roll center. Building anti dive into the upper a arm mounts, taller upper ball joints to increase camber gain, raise front roll center. Twist in spring spacers to stiffen front springs, but not installed so as to not raise ride height..... without any disassembly. Use proven competition alignment settings. I've seen some stock cars use some pretty well thought out methods to greatly improve handling and still use mostly stock components...just relocate mounting points and some taller ball joints in the right places. HTH
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#2
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In the suspension shootout between Herb Adams and Dick Gulstrand, Adams won the matchup with softer springs and the largest sway bars he could bend up. I believe they were 1 5/16 inch front, I can't recall the rear size.
For those of you that don't know who Herb Adams is, he was the suspension designer at Pontiac and designed the original suspension for the T/A. Dick Gulstrand was mostly noted for Corvette suspensions and his approach was stiff springs and small sway bars. In any published information Adams has always said large bars to control body roll and soft springs that more easily conform to road irregularities to keep the tires in contact with the road. Here is a link to the thread talking about the shootout: http://forums.maxperformanceinc.com/...Dick+Gulstrand There are definitely two schools of thought about what makes a better handling 2nd Gen F body. In my own 73 T/A I followed Adams suggestions for a street driven autocross car and had great success with it winning the local SCCA championship for the year I ran the car. There is a reference to another shootout that Ken Crocie refers to that I have never read, someone asked for a link to the article, but none was ever furnished.
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Brad Yost 1973 T/A (SOLD) 2005 GTO 1984 Grand Prix 100% Pontiacs in my driveway!!! What's in your driveway? If you don't take some of the RACETRACK home with you, Ya got cheated ![]() ![]() ![]()
Last edited by Sirrotica; 06-13-2015 at 10:00 AM. |
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#3
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Quote:
Btw, I followed the Adams approach with my 2nd gen birds since the early 80's and never had a problem with front end dive/rear axle unloading during hard braking. But I also did whatever I could to remove unnecessary weight from the front of those cars which helped considerably. Regarding the stock front springs: I trimmed mine to get the stance I wanted. Ride was always great but firm and the cars handled beautifully on the street and didn't swap lanes unexpectedly when hard cornering and encountering rough, washboard surfaces unlike friends Camaros with rock hard springs.
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"Objects in mirror are closer than they appear"
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#4
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I had Dave from Pro-touring F-body.com help me design the right suspension system based on the specs of my car and what I planned on doing with it, which was auto cross and spirited street cruising. I went with solid body mounts, welded DOM tubing subframe connectors, Dave's Competition front and rear spring kit (lowered 1.5" from stock height), heavy duty tie rod sleeves, adjustable shocks, front swaybar brace to go with my factory 1.25" sway bar , G-bar braces, and heavy duty rear swaybar drop links to go with my factory 1" sway bar.
Also, tubular upper and lower controls arms from DSE, 1LE front disc brakes done with SSBC parts, Willwood rear discs on a Moser 12 bolt rear and TKO-600 5-speed. I did all these mods at the same time, and the results were nothing short of astounding compared to how it handled in stock form. The ride is pretty stiff, but it's not harsh. The car is on rails, so much so that I had to change to a road race oil pan with trap doors to keep oil at the pick up during hard cornering.
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John ![]() "There are no stupid questions, but there are a LOT of inquisitive idiots!" |
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#5
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It all depends on what your rear like in handling.
Problem for me with Herb Adams soft front springs big bar was brake dive. Soft front spring lets front dive under moderate to hard braking . That unloads the rear and then the tires have less traction for braking allowing rear lock up esp in a turn when they were set great for less dive. Stiffer front spring less dive more weight on the rear more braking traction. When I autocrossed my 78 TA hard and alot in CP with sticky DOT autocross tires or even stickier road race slicks I found for me, 500- 700 lb/in front springs 1 1/4 WS6 front sway bar, stock rear springs , solid frame bushings(tried every one for fit and drop) solid lower A arm bushings , solid/Nyliner Herb Adams upper A arm bushings,SMALL 5/8 rear bar. Guldstrand valved Bilsteins all corners(ant they work good for drag racing too!). Yes had those poor fitting Moroso subframe connectors as it was a T top car. They helped a little on the sag of the doors when car was jacked up. Ride was softer than my factory full sized Bronco and very streetable.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune [email protected] 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs 1964 Corvette Coupe 327 4 speed |
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#6
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Car Craft March 1988- "Street Suspensions"
Car Craft tested 4 different F-Body suspension kits. Included was a Camaro from Guldstrand, a Camaro from Herb Adams, and a Camaro from Rancho Suspension. We (H-O Racing) provided my G.M. Karyn Frost's 75 fully optioned Esprit, using the full H-O suspension kit. Kit included front 1-3/8" sway bar, rear 7/8" sway bar, front H-O springs @ 520 PPI, poly bushings all around, Koni shocks stock rear spring. To equalize the competition, the same wheels and tires were switched from car to car. We Won. It was picked as the best "driver" by 3 of the four editors involved. Navy- this what I recommend. 1:Front sway bar. Use a stock 1-1/4" from a T/A or an aftermarket 1-5/16" or 1-3/8". there's a reason T/As were the best handling cars of the era. 2: rear sway bar use a stock 3/4" or 13/16" or aftermarket 7/8". 1" is just too big. see above reason ! 3 shocks : Koni's or KYB Gas-a-Just. KYBs are the best bang for the buck. 4: tires : There are a number of sticky 15" tires around, but to get max cornering power you will need to step up to 17" or 18". 5: poly bushings.New stock rubber is fine if you use steps 1,2, and 3. If you step up to sticky tires (autocross worthy) poly is a must. 99: frame connectors (a must with T-Tops as they will pop out with aggressive cornering) , solid body mounts, stiff rear springs. BTW we beat a new '92 ZR1 on the slalom course-69.34 mph vs 67.29 and .96 G vs. .93G-with my 64 GTO. Sep '92 Car Craft
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION Last edited by KEN CROCIE; 06-16-2015 at 09:47 AM. Reason: left out info |
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#7
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Ken, I remember that test and still have the article stashed away. That 64 was so impressive I did my 70 GTO using many of your parts.
One major difference though was I seem to remember your 64 having a 700-R4 and maybe a 3.08 gear.(?) Do you still have that car?
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"Objects in mirror are closer than they appear"
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#8
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We seem to have lost the engineer types and the guys whom have never really thrashed on a car before. Dont hate, just an observation. Listen to Ken Crocie. The originator of Pro Touring? He was running 16x9.25 3 piece Simmons wheels in the mid 80's on his 64 goat. Wasnt invited personally to compete in any of the "Real Street Eliminators" (car craft) because he owned a business, read "nobody would have a chance". Oh wait, remember the shoot out in 79'. He was able to procure customers cars and do very well in the following years. Larry Yates circa 85'-- Anybody? You guys do what you do-cheers.
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#9
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And we're off!
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'78 Macho T/A DKM#95, 460cid, SRP pistons, KRE 310 D ports, 3" pypes, Hooker 1 3/4" headers, hydraulic roller, 10" Continental, 3.42 gears 11.5 @117.5mph 3900lbs ![]() ([_|_] ##\|/##[_|_]) |
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#10
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O.K. Phil: yes, yes, and yes.
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GOOD IDEAS ARE OFTEN FOUND ABANDONED IN THE DUST OF PROCRASTINATION |
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#11
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Im not sure what your budget is and im certainly no Ken Crocie but ill throw my hat in the ring since I have a little experience....
Ive messed with the stock WS6 swaybar and Bilstien shock type setups on my 67 GTO. They are nice and are way better than stock but after tinkering around, my advice is to call up SC&C or Ridetech. Tell them what you want to do with your car. Get out your credit card and do what they tell you to do. Wait for the UPS man. Install your parts and enjoy the nicest riding and handling musclecar you could ever imagine. I did the SC&C stage II chassis with Ridetech HQ shocks, stock spindles and tall balljoints and I do not regret it a bit. My GTO handles like a modern car and rides fantastic. I did mine pieces at a time. I didn't do it all at once. There's documentation in my build thread if you're interested. There's a link in my signature.
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-1967 GTO HO Restomod. PKMM 433ci, SilverSport T56 Magnum 6spd, Moser 9", SC&C and a bunch of other pro touring goodies - Build Thread http://forums.maxperformanceinc.com/...615847&page=23 |
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#12
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I really appreciate all the input and knowledge. Thanks to you guys I've learned more about suspension in the last week than up to that point. The articles you all linked are awesome.
My overall goal is to have a high quality street muscle car. I'm not trying to drag race or auto-cross. With the power I was making with my engine finally running right, any kind of accelerating turns had the car trying to change lanes on me. Since my car had no rear sway bar at all, I went ahead and got ordered over the weekend and installed on Monday. It is a night and day difference. As nice as it would be to just break out the credit card and go to town, I've got to "Johnny Cash" (once piece at a time) this thing. I took a look at the bushings when the sway bar was going on. Those will definitely be the next items to be replaced. Sine this car spent the first 35 or so years of it's life in Pennsylvania, it's going to be a lot of fun getting them off. I've already started hitting them with WD-40, and I won't start that process for a month or so. I've got a mini-starter on order and I'll probably move the battery to the trunk when that comes in and I have to re-wire the starter anyway. |
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#13
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NH16,
One thing I didn't see mentioned (unless I missed it) is alignment specs. This really improved the cornering and stability of my car: +2° or +3° castor. Or as much as you can get. The limitation with stock control arm will be the bolt length and the steering column will get in the way. You basically stuff as many shims in the rear of the upper control arm as possible. This provides high speed stability like new cars have. -1° camber. This helps with cornering. Any more on a street car and you will wear the inside of the front tires quicker than you may like. 1/16" toe Made a big improvement on my car I wish I'd done it years ago
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'78 Macho T/A DKM#95, 460cid, SRP pistons, KRE 310 D ports, 3" pypes, Hooker 1 3/4" headers, hydraulic roller, 10" Continental, 3.42 gears 11.5 @117.5mph 3900lbs ![]() ([_|_] ##\|/##[_|_]) |
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#14
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Navy, any updates on your handling project? Thanks.
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"No replacement for displacement!" GTOAA--https://www.gtoaa.org/ |
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#15
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Besides all the other suspension vendors previously mentioned, another one I and others have used with great success is UMI, home is here in the USA (Pennsylvania) and yiu can get their products direct from them or through Summit. They carry alot for the 1970-81 Firebirds.
https://www.umiperformance.com/home/
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"No replacement for displacement!" GTOAA--https://www.gtoaa.org/ |
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#16
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I've used Global West, Hotchkiss, and PTF-body stuff. All good.
Hotchkiss - IMHO is the best, esp spring and SFC's. Expensive *** though! For price, quality, one-stop shopping......PTF-body for sure. |
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