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-   -   Cross Weight, and stuff. (http://www.clubcobra.com/forums/backdraft-racing/142313-cross-weight-stuff.html)

bobcowan 05-11-2019 02:02 PM

Cross Weight, and stuff.
 
I'v driven my car about 1200 miles now. Still getting used to it. But I didn't think the car felt that precise. I had some time today to mess with it.

I raised the front ride height about 3/4". I managed to scrape the bottom of the scoop a couple of times.

Then I put it on the scales. This is the baseline.
https://i.imgur.com/amm8URS.jpg

https://i.imgur.com/XgLD7Ae.jpg

I made a minor adjustment to the left front
https://i.imgur.com/Wphlt9r.jpg

https://i.imgur.com/BC1CSMn.jpg

This is with about 1/2 tank of fuel, and no weight in the driver's seat. Sometimes I'm in the car alone, and sometimes not.

Unfortunately, there is no adjustment for the rear, or I would have taken a little weight out of the right rear. If I was racing this car, I would make that adjustable.

I also checked the front end alignment. Caster and camber are fine. But it had 1/8" toe out. I changed that to 1/16" toe in.

Did it help? YES! A noticeable improvement in feel and ride. I like it.

patrickt 05-11-2019 05:11 PM

For an exceptionally entertaining corner-weight thread, click here: http://www.clubcobra.com/forums/all-...ht-my-spf.html You can read all eight pages, or skip to the very last post, which sums it up nicely.:cool:

bobcowan 05-11-2019 07:27 PM

Yeah, I remember reading that years ago. Adjusting the corner weights on a short wheel base, light weight car is an important step in getting it to ride and handle correctly. As you can see, the car was pretty far off from straight. I improved on it, but didn't get too OCD about it. If the rear springs had been adjustable, I would have spent more time to get it closer. But only because I had it on the scales already.

I just took a short drive this afternoon. But it really did feel better.

Now, to work on the brakes. :)

bobcowan 05-12-2019 03:22 PM

I took a 220 mile ramble through the mountains today. What a difference! Not quite a new car, but certainly much improved. Very stable in the corners, very smooth and predictable. Much more settled. I didn't think it would make that big of a difference, but it did. Now it makes me want to go out and play with it some more, to see if I can get it any closer.

Now, to work on the brakes.

hauss 05-14-2019 11:36 PM

Rear adjustment
 
Quote:

Originally Posted by bobcowan (Post 1461641)
I'v driven my car about 1200 miles now. Still getting used to it. But I didn't think the car felt that precise. I had some time today to mess with it.

I raised the front ride height about 3/4". I managed to scrape the bottom of the scoop a couple of times.

Then I put it on the scales. This is the baseline.
https://i.imgur.com/amm8URS.jpg

https://i.imgur.com/XgLD7Ae.jpg

I made a minor adjustment to the left front
https://i.imgur.com/Wphlt9r.jpg

https://i.imgur.com/BC1CSMn.jpg

This is with about 1/2 tank of fuel, and no weight in the driver's seat. Sometimes I'm in the car alone, and sometimes not.

Unfortunately, there is no adjustment for the rear, or I would have taken a little weight out of the right rear. If I was racing this car, I would make that adjustable.

I also checked the front end alignment. Caster and camber are fine. But it had 1/8" toe out. I changed that to 1/16" toe in.

Did it help? YES! A noticeable improvement in feel and ride. I like it.

Are you sure about no adjustment for the rear? My car does they are hard to get at had to remove the rear wheels to get at them.Should be at the top of the rear springs that is where mine are.

bobcowan 05-15-2019 06:11 PM

Is there a jacking pad up there? I couldn't see one, and assumed it was a fixed spring pad?

I may have to re-visit this when I get some free time. It probably wouldn't make a noticeable difference. But it would give me something to do, and helps satisfy my OCD. :)

Cashburn 05-16-2019 11:48 AM

Rear is adjustable at the spring pad.

bobcowan 11-07-2019 04:06 PM

So, I had some time this week to play around with it a bit more.

The rear spring does in fact have an adjuster. Thanx for that.

Adjusting the front is pretty easy. Jack up the frame to take the weight off the springs, reach in there and turn the color. Simple.

Start by jacking up the front and adjust the collars so they are just touching the top of the springs to the mount. Put the car back on the ground and settle the suspension. Some folded plastic trash bags are slippery enough to work like greased toe plates. Check the ride height front and rear.

Adjust the ride height in the front by exactly the same amount. They might not be exactly even, and that's OK. Just lower them by the exact same amount on each side until you get the ride height you're after.

The rear is more difficult because it's not a coil over, it's a captured spring. I Adjusted mine by counting the threads on the adjuster, and making sure they were the same. That made the rear ride height pretty close side to side.

This is the rear adjuster.
https://i.imgur.com/uc56yCG.jpg

These were very difficult to move. They were a little rusty, I sprayed them with PB Blaster and let them sit over night. I have these two adjuster tools made for different cars. The bottom one sort of work. The top one not at all. I ended up using a drift and a hammer.
https://i.imgur.com/fSWYVGL.jpg

After working with it for a while, This is where I ended up:

Ride height today:

Front- 7.00"...……. 7.375"
Rear-- 8.25"...…… 8.25"


Corner weights: Today
Front- 670#.....598#.... 72#
Rear- 679#.....670#.... 9#

Cross Weight 1277 - 48.79%
Left- 1359#... 50.25%
Rear- 1431#....52.92%
Cross- 1290#... 47.78%
Total Weight- 2704


Corner Weights: When I started (See above post)
Front- 738#.... 549#.... 189#
Rear - 591#...787# ….. 196#

Cross Weight: When I started
Left- 1329#.... 49.88%
Rear- 1378#.... 51.72%
Cross- 1139#... 42.74%
Total Weight- 2664#


https://i.imgur.com/8gZLDYg.jpg

https://i.imgur.com/Nz2ZVK4.jpg

It weighs a little more than when I first started because the fuel tank is full today.
Sorry about the crappy photography skills.

It's cold and snowing today, so I can't test drive it. But Saturday is supposed to be almost 70* and sunny. I'll let you know.

Am I happy with these numbers? Not sure. The OCD Racer in me tells me I need to work a little harder and do a better job. But the street car driver in me says it's fine, don't worry about . Who will win? IDK, I guess we'll just have to wait and see. ;)

bobcowan 11-07-2019 04:12 PM

I also noticed there are some gaps/openings in the trunk. Especially around the roll bars. Since I'm not afraid to drive this car in rain and snow, I should probably fix that. Bathtub caulk in a big tube usually does a nice job of that.

RB60 11-07-2019 05:59 PM

Quote:

Originally Posted by bobcowan (Post 1468321)
I also noticed there are some gaps/openings in the trunk. Especially around the roll bars. Since I'm not afraid to drive this car in rain and snow, I should probably fix that. Bathtub caulk in a big tube usually does a nice job of that.

You drive a Cobra in the rain and snow?
I've been caught in rain, but snow? You have more "balls" than I do!

bobcowan 11-07-2019 08:10 PM

Well, it's not a plan. But it happens. I guess I had better be somewhat prepared. :)

Alfa02 11-07-2019 10:20 PM

Speaking of cross weight, weight jacking, etc. I recently brought a JCF 289 Slabside which I thought sat too high, and found a new shop here in Tacoma Wa. (Rule Garage) which handles 4-way alignments, weigh jacking and such. They also do great fab. work, up to complete restorations, (They are our "Snake Handlers") with Rob Sweet still as the (Snake Charmer) Anyway, before we even got the lowering or the alignment, they found a issue with my steering rack and steering u-joints, that needed attention. long story short, they promised a much safer, and better driving car then I brought in. So anyone in the greater PNW, that needs work on they car, we now have a second shop to bring our cars to. Another member (EM-0785) has his car there for elec. issues and minor repair, and couldn't be happier with their work too. If anyone need info. on the shop, contact me, or go to Rule Garage on line, (Tyler and Andy Osborn, Father & Son, Ford guys though & though) Anybody that can make a 74 Ford Maverick a Pro-Rallye car that can handle, can work on my cars any day ;) Cheers TommyRot.

FredG 11-09-2019 05:12 AM

Hi Bob. Two questions. Where did you measure to get these numbers?

Ride height today:

Front- 7.00"...……. 7.375"
Rear-- 8.25"...…… 8.25"

and after you adjusted the front, did you still have play in the spring with the suspension hanging?

Thanks

Fred

Seagull81 11-09-2019 06:14 AM

Don't forget to recheck your front end alignment after raising or lowering your car. Toe out will make your car spooky on the street.

bobcowan 11-09-2019 06:40 AM

Quote:

Originally Posted by FredG (Post 1468371)
Hi Bob. Two questions. Where did you measure to get these numbers?

Ride height today:

Front- 7.00"...……. 7.375"
Rear-- 8.25"...…… 8.25"

and after you adjusted the front, did you still have play in the spring with the suspension hanging?

Thanks

Fred

I used the outriggers. In the front just before the weld, and in the rear at the jack point. It sits a little bit higher than most cars I've seen, maybe about an inch. But around here, that seems to keep the nose out of the concrete.

Quote:

Originally Posted by Seagull81 (Post 1468372)
Don't forget to recheck your front end alignment after raising or lowering your car. Toe out will make your car spooky on the street.

This is true. Front and rear should have a smidgen of toe in.

FredG 11-09-2019 08:10 AM

Thanks

bobcowan 11-09-2019 07:53 PM

Went for a short drive today, <300 miles. Mostly 2 lane mountain roads, some freeway. Because of traffic, never got much speed up. The car rides and handles very nicely. No bad habits.

So, will I leave it be? No, I think not. I think I can play with it, and make it just a little bit better. :)

IMLost 05-12-2020 07:13 PM

Bob, I have used this thread to help me go through this a year later. Did you replace the rear springs? Or was their rating in your process. I had my car weighed and compared the info. Don’t know if i need to replace the springs to totally start fresh.
Didn’t;t mean to drag a skeleton out but this is helpful info

spdbrake 05-12-2020 07:39 PM

IMLost, you'd probably benefit from new rear springs. Yours is an early car like mine and probably has progressive (coils thinner in dia at top and bottom) springs.
I noticed a considerable ride improvement after the swap. The bone jarring was gone. I'd also change the lower upper and lower spring perch seats they are most likely disintegrating.

https://www.ecstuning.com/b-genuine-...h/33531135420/
https://www.ecstuning.com/b-genuine-...m/33531136385/

https://www.iconicparts.com/springs-rear.html

IMLost 05-12-2020 08:03 PM

Thank you I plan on ordering them tomorrow. After all of my digging I found out that the springs are made for Backdraft (or so I’m told) in South Africa. I found some Bilstein but am not sure of their spring weight. If so that has to be some of the few in house items. Those pictures we really helpful in trying to figure my car out. Im 5/8 higher on the lip check, and after the threade count difference I’m of...5/8. Will go new all around. Love these dinosaur Cobras!


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