[HWYSTR455]

New tank in, runs great. Now on to some tune refinement.

Had a chance to take a ride through the mountains, had a blast!


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[bulletpruf]

Originally Posted by HWYSTR455

New tank in, runs great. Now on to some tune refinement.

Had a chance to take a ride through the mountains, had a blast!

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Outstanding! Car looks great!

[HWYSTR455]

Thanks!

On the way back I heard a 'clunk' in my rear inner fender well, sure enough, looked when I got home, and it pitched the stick-on wheel weights on passenger rear.

I can feel a vibration around 75-80mph +. Sux. I will pull the wheel after the holidays and get it balanced. Just a bummer is all.

The new tank fill neck has a modern surge baffle, which I appreciate. No more gushing out when the tank reaches full. That ticked me off when it gushed, because I would have to polish the exhaust tips, gas would dry on them.

I wish the tank had a little more capacity, it's like 23gal, 26 or more would be sweet.


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[HWYSTR455]

UPDATE:

So have finally gotten to a point where I can dial in the suspension, knew the springs I had were too weak, since I have considerable wait added to the frontend from the endura bumper, twin coolers, serp belt setup, and the intake setup.

Called up GW to get springs, and they sent me a set, and the thing was worse than the springs I had on it before. Called them, told them the car was sitting on the bump stops, and the guy (not Doug) told me it has to be something else, and asked me what kind of shocks I had. Um. Shocks don't hold the car up.

So they sent me another set. Just as bad. Called them back and told them that the springs that were on it before I started the resto were a little soft to begin with, and asked what those were (rate), and was told they were 680 lbs. Ok, then I need like a 750, or maybe even an 850, and was told it would be too much and they don't have any. AND, because I installed the sets I can't return them. (They used to accept them in the past).

Anyway, in a search for someone that could make springs to my specs, I found Coil Spring Specialties, and placed a build order for some 850 springs, 14" free height. That was calculated by using the previous springs as a baseline, and accounting for added weight on the front end. Those springs should be ready in about another 2-3 weeks.

In the interim, I ordered some off the shelf Afco springs that are 850, but are only 9.5" tall, which would require a spacer, which I also got, and adjustable one. I dialed the adjustment in order to achieve the desired 14" free height, but due to the shorter spring, rose the car too high, so dialed it to 13", which put the front end right where I wanted it, 1.5-2" lower than the rear.

I made several adjustments to the shock settings trying diff combos, and it's pretty close. I will have to try it with the new springs when they come in, since the spring is taller, and will respond diff than a short spring with a spacer. And no, it doesn't ride like a truck. It's stiff, but still does absorb bumps and tracks well.

So, I am pretty close to the desired setup, may drop back to a 750 lbs spring that's 15" or 16" free height, will just have to figure that out once I get the 850s.

As an example, the 560 lbs spring that I just removed, made the car rest on the lower control arm bumpers. The 680 lbs springs that were in it as it lived as a LeMans were the 680 lbs, and those would bottom and bounce off the lower control arm bumpers on dips and stuff. So I know I'm close with the 850s. Might need an 800 lbs spring, but will try a taller 750 lbs spring beforehand.

Also, as soon as I can, I will take the car to get it's corner weights on some race scales, so I know what I'm dealing with.

Questions/comments/suggestions are appreciated.



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[bulletpruf]

Originally Posted by HWYSTR455

UPDATE:

So have finally gotten to a point where I can dial in the suspension, knew the springs I had were too weak, since I have considerable wait added to the frontend from the endura bumper, twin coolers, serp belt setup, and the intake setup.

Called up GW to get springs, and they sent me a set, and the thing was worse than the springs I had on it before. Called them, told them the car was sitting on the bump stops, and the guy (not Doug) told me it has to be something else, and asked me what kind of shocks I had. Um. Shocks don't hold the car up.

So they sent me another set. Just as bad. Called them back and told them that the springs that were on it before I started the resto were a little soft to begin with, and asked what those were (rate), and was told they were 680 lbs. Ok, then I need like a 750, or maybe even an 850, and was told it would be too much and they don't have any. AND, because I installed the sets I can't return them. (They used to accept them in the past).

Anyway, in a search for someone that could make springs to my specs, I found Coil Spring Specialties, and placed a build order for some 850 springs, 14" free height. That was calculated by using the previous springs as a baseline, and accounting for added weight on the front end. Those springs should be ready in about another 2-3 weeks.

In the interim, I ordered some off the shelf Afco springs that are 850, but are only 9.5" tall, which would require a spacer, which I also got, and adjustable one. I dialed the adjustment in order to achieve the desired 14" free height, but due to the shorter spring, rose the car too high, so dialed it to 13", which put the front end right where I wanted it, 1.5-2" lower than the rear.

I made several adjustments to the shock settings trying diff combos, and it's pretty close. I will have to try it with the new springs when they come in, since the spring is taller, and will respond diff than a short spring with a spacer. And no, it doesn't ride like a truck. It's stiff, but still does absorb bumps and tracks well.

So, I am pretty close to the desired setup, may drop back to a 750 lbs spring that's 15" or 16" free height, will just have to figure that out once I get the 850s.

As an example, the 560 lbs spring that I just removed, made the car rest on the lower control arm bumpers. The 680 lbs springs that were in it as it lived as a LeMans were the 680 lbs, and those would bottom and bounce off the lower control arm bumpers on dips and stuff. So I know I'm close with the 850s. Might need an 800 lbs spring, but will try a taller 750 lbs spring beforehand.

Also, as soon as I can, I will take the car to get it's corner weights on some race scales, so I know what I'm dealing with.

Questions/comments/suggestions are appreciated.

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Sounds like you're getting there. Coil springs can be a real pain in the a$$, can't they? Rare that I find some that are just right.

Any particular reason that you're not doing coil-overs? After what I went through with my '68 Lemans convt. a few years ago trying to find the right springs, I'll do coil overs on my next one.

[HWYSTR455]

The problem with coil springs is most are generic spun wire, and tolerances are all over the board. 'Accepted' tolerances are in the 8-12% range, which means for example, on a 500 lbs spring, can vary from 40 lbs - 60 lbs. Imagine if you have 2 springs at the end of the tolerances? 440 - 560 from side to side, and you get the dreaded 'lean'.

Coil overs. I asked that question in the 80s, and it was explained to me in this way:

The longer the piece of 'wire', the more granular the rate changes as it bends.

Imagine this. You have 2 identical thickness metal rods, one is 18" long, and the other 36". If you grab either, and you slowly apply pressure to bend them, the longer one begins bending 1st, right?

Traditional coil springs are 5" or 5.5" diameter. Most are in the 16-20" free height range. Traditions coil over springs are 2.5 diameter, and in the 10 - 14" range. If you take one of each, and straighten them into a rod, which one is longer?

Packaging coil overs and strut/spring assemblies is much easier and cheaper to use and produce. In a performance app, generally, above a certain weight, all the OEs use strut/spring combos, because the coil spring on a strut is much longer 'rod'. An exception is on lighter cars, and in canted/cam type suspensions.

GW is now crossing over to coil over setups, and it looks like they are basing it off the QA1 design(s), so if you want to go that route, the QA1 stuff is the best. The 'hybrid' setups with tapered springs, are basically a strut/spring setup. The 'Pro' stuff is cutting edge, excellent, but not cheap. That also is a factor for me, I already have an investment if the traditional coil spring suspension (control arms, bearings/bushings, etc). Each shock is around $2k ea, and you basically need to run their' control arms too. Front and rear kits are in the 7500 - $8400 range.

https://qa1.net/GM/Car/GTO/1968-1972/Handling-Kits/

Its still somewhat hybrid, the springs are still tapered, but it's built for heavier cars.


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[HWYSTR455]

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Here's the front end drop comparison, the 1st pic is with the 560 lbs springs, the 2nd with the 850 lbs springs.

EDIT: The 1st pic is with 275/40/18s, the 2nd is with 255/40/18s.


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