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Brodizzle83

Emailed Birchmount Springs and...

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I emailed Birchmount Auto Spring in Canada about the rear mono leaf and said it would be around $360 shipped. Doesn't that sound a bit high? I thought I read that people were paying about $250ish shipped for them? Not sure, but I don't know if I trust myself to build my own rear coilover kit. Might just have to bite the bullet on the spendy mono leaf.808ca63d9528583c345af6f476e36074.jpg

 

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I emailed Birchmount Auto Spring in Canada about the rear mono leaf and said it would be around $360 shipped. Doesn't that sound a bit high? I thought I read that people were paying about $250ish shipped for them? Not sure, but I don't know if I trust myself to build my own rear coilover kit. Might just have to bite the bullet on the spendy mono leaf.

 

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Do not forget that we're Canadian up here in Toronto.

 

Did you speak to Tony himself (owner) or one of the employees?

 

Was the quote in Canadian dollars or US?

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Haha yeah I know they're in Canada. I guess I figured they would give me a USD price since I told them I needed them shipped to Duluth, Minnesota, but I emailed him back and asked if the given price was USD or Canadian.

 

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Tony (Birchmount) doesn't do a monoleaf, he builds a replacement from smaller multiple leaves. He will try his best to get a proper spring rate knowing the car will be dropped, to prevent bottoming out.

 

The one drawback to what he does is that the replacement spring is not the same width as the original fiberglas spring under the car, it is narrower, (the same width as a regular car leaf spring), and because of the stacking of the leaves the replacement is thicker in the center area than the original.

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There's another place in S. Carolina that makes them. Flex a form maybe??

 

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I last spoke with Mark at Flex-form 5 years ago, at that time I WAS considering a purchase of their product, but I never got around to doing it, difference of the dollar value & shipping costs.

 

Here is what he wrote to me on an email I received on the topic.

 

 

 

Hello Steve,

 

We have never found any information on original spring rates for these cars. We have rated a couple of used springs and found them to be in the 270 – 275 lb/in. range. But they were well used and from standard suspension models.

The springs we have made for replacements on upgraded suspension models have been in the 300 – 315 lb/in range. We have made one spring for a modified suspension Cutlass that gave a drop similar to what you are looking for with no rate reduction. For this application we used our high arch spring blank rather than the Corvette spring blank we would otherwise use.

 

Hope this helps you.

 

Mark 

 

This left me with the impression that they did not have a respectable FE3 leaf to mount into a spring rate tester to see what the actual rate of an FE3 leaf is. I have always been under the impression that it is near 350 lbs. per inch.

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I got a replacement about 2 years ago for free actually. It was the last one in the warehouse and the guy gave it to me for zero dollars. He just wanted my old spring back. They were a sub contractor for GM and made the monoleafs for Olds, Pontiac, and Buick I believe. Pretty awesome. I searched for one for awhile. Didn't like Flex a Form much. Was going the Birchmount route until I found this other place and emailed them. Didn't want a used junkyard one unless that was the last resort. I had an extra one from a Cutlass a few months ago and got rid of it. If I still had it you could have had it.

 

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I last spoke with Mark at Flex-form 5 years ago, at that time I WAS considering a purchase of their product, but I never got around to doing it, difference of the dollar value & shipping costs.

 

Here is what he wrote to me on an email I received on the topic.

 

 

 

Hello Steve,

 

We have never found any information on original spring rates for these cars. We have rated a couple of used springs and found them to be in the 270 – 275 lb/in. range. But they were well used and from standard suspension models.

The springs we have made for replacements on upgraded suspension models have been in the 300 – 315 lb/in range. We have made one spring for a modified suspension Cutlass that gave a drop similar to what you are looking for with no rate reduction. For this application we used our high arch spring blank rather than the Corvette spring blank we would otherwise use.

 

Hope this helps you.

 

Mark 

 

This left me with the impression that they did not have a respectable FE3 leaf to mount into a spring rate tester to see what the actual rate of an FE3 leaf is. I have always been under the impression that it is near 350 lbs. per inch.

 

I've installed rear coilovers on a few FE3 cars, and using 300 lb/in springs ride make the car noticeable stiffer than stock. I now use 275 lb/in springs. They still feel stiffer, but they are a little nicer riding than 300. FE3 springs definitely aren't more than 275 lb/in and I would actually guess them to be about 250 lb/in.

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I've installed rear coilovers on a few FE3 cars, and using 300 lb/in springs ride make the car noticeable stiffer than stock. I now use 275 lb/in springs. They still feel stiffer, but they are a little nicer riding than 300. FE3 springs definitely aren't more than 275 lb/in and I would actually guess them to be about 250 lb/in.

What ratings do you run up front?

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I've installed rear coilovers on a few FE3 cars, and using 300 lb/in springs ride make the car noticeable stiffer than stock.

Well that's what I am looking for.

 

If I drop the car I do NOT want any contact between the rear quarter lip & the top of the outer edge of the tire. As Mark stated he did not have any access to an FE3 leaf, the sample he did have was from an FE1 car that was worm out & it was tested at 270lbs. The fenders on the 1st gen GP's cut across the tops of the tires & the pinch weld seam on the rear quarters is not clear of the outer edge of the top of the tire (when the 16x8 crosslace wheels are used), if the lowering spring isn't stiff enough there will be contact under near full rebound conditions.

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That's what I was wondering as well.......

 

a single leaf is compressing both ends at the same time when in the tester whereas a single coil is just that...a single coil

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A little concerned about my new coilover springs, I went front 325#, rear 225# and now those numbers seem soft. Who knows, it may be a blessing with the variable dampening struts and I may be able to drive a luxury car to the track and then dial the struts up and have it hard as a rock.

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So the big question is 270# total, as in 135#/side or 270# total.

I said the same thing twice, lol. I may not know what I'm saying but I know what I mean, lol.

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What ratings do you run up front?

 

 

A little concerned about my new coilover springs, I went front 325#, rear 225# and now those numbers seem soft. Who knows, it may be a blessing with the variable dampening struts and I may be able to drive a luxury car to the track and then dial the struts up and have it hard as a rock.

 

Never ran front coilovers. Cutting coils works too perfectly on the front of these cars for me to bother with them. So I really don't know if 325 lb is soft for the front, but 225 is probably close to stock for the rear on a gen 1. I wouldn't worry about that, especially if you have a large aftermarket or gen 1.5 rear sway bar. Gen 1 cars had twig bars in the rear. I'm no pro driver, but 300 lb rear springs and a 20/22mm bar makes the back end want to snap out on course for me. That's just way too much stiffness. W-bodies, especially first gens, weigh nothing in the rear.

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 I wouldn't worry about that, especially if you have a large aftermarket or gen 1.5 rear sway bar. Gen 1 cars had twig bars in the rear. I'm no pro driver, but 300 lb rear springs and a 20/22mm bar makes the back end want to snap out on course for me. That's just way too much stiffness. W-bodies, especially first gens, weigh nothing in the rear.

 

Good bars are all but extinct, I was under there figuring today and with a little creative bracketry I think a second bar will fit just above the first. The hangers shouldn't be a problem for me to mod but the bar end mounts will have to be machined, probably opt for steel rather than aluminum. If I can make that work I'll share the details.

 

Does anybody know if an FE3 car had different sway bars front and rear than an FE1 car? Just curious where I am with spare parts.

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Just use one bigger bar. Others around here are far more familiar with dimension specifics but I know there are beefy rear 1.5 gen ones out there. I feel like two bars is asking for additional binding. Isn't all that rubber bushing binding enough?

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It's worth the experiment, other cars have been modified to run dual bar setups. I'd like to do poly bushings on them too which will slip a bit better than the rubber. The worst thing that can happen is I take the second one out and look for a single bigger bar and I have some interesting dual bar brackets to hang on the wall and laugh about later.

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Thank you. That was what I was missing. My regal came with no bar and no aux springs. Let's just say I didn't like it. Now with the steel 3leaf and a small bar, it's far tighter in the back than the front. Also lower. I wish I had the energy to address that last bit.

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Thank you. That was what I was missing. My regal came with no bar and no aux springs. Let's just say I didn't like it. Now with the steel 3leaf and a small bar, it's far tighter in the back than the front. Also lower. I wish I had the energy to address that last bit.

You have three stacked steel leaf springs?

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Yep. Kind of an unconventional setup but the spring shop had it premade for this application somehow. Apparently I am not the only one to haul a lot of s**t in da trunk. It actually lowers it and is damn firm. The front is like jelly compared to the back on my regal.

You have three stacked steel leaf springs?

Edited by vipmiller803

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