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Old 02-28-2010, 09:26 PM   #1 (permalink)
ecomonkey
 
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lowering an echo and rake angle

i am going to heat the coil springs on my echo, to lower the car for aerodynamics only. dont care about looks, (heating the coils to adjust height is commenly done on racecars) would lowering the front 2" and the rear 1" help or hurt aero? it seems to already have about an inch of positive rake (if thats what its called when the front is lower than the back) i.ve not been able to answer this question satisfactorily by looking at threads on rake.i am going to adjust the ride height next week, its either 2" front and rear or the previous 2"and 1". my race car builder friend, says his car picked up speeds in the strait-a-ways with a little more positive rake. suggestions? the picture is stock ride height.

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Last edited by moonmonkey; 02-28-2010 at 09:28 PM.. Reason: spelling
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Old 02-28-2010, 09:53 PM   #2 (permalink)
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Lowering usually improves aero unless you have a very smooth belly and some wheel fairings.

I would install spring compressors as they are reversible and cheap and don't change the spring rate as much. If you do heat the springs do it on the tighter end of the coils which is the softer end. You don't want to lose the stiffer part of the spring.

I think rake should be nose down, but just one or two degrees. Your friend would probably have gained even more from a flatter rake. Make sure you put in some ballast in the drivers seat when you are setting the rake.
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Old 02-28-2010, 10:11 PM   #3 (permalink)
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I'm not to fond of heating springs to lower a car, although it has been done quite a bit. I disassembled my struts and cut them with a cut off wheel on my angle grinder. If your bottom spring perch is the style that cups the spring then it is easy to cut them, however if your spring is a full circle on the bottom and that is what holds the spring onto the perch, then you only option might be to heat them. Although I would probably use the clamps first for a Proof Of Concept before taking the dive off the deep end

I lowered mine 1.5" and have a slightly positive rake, can't say it helped the mpg pursuit by any amount I could measure. Even at only 1.5" below stock I have bottomed hard enough to hit my header on the ground and destroy my o2 sensor, but that was a pretty radical gas station apron.
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Old 02-28-2010, 10:50 PM   #4 (permalink)
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Your race builder friend approves of this heating springs for lowering?

I'd try the spring compressors first- so you can see if you like it. Then cut 'em. I doubt you'll be able to detect an fe improvement, but theoretically it's supposed to help.
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Old 03-01-2010, 09:59 PM   #5 (permalink)
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hate spring clamps

i put spring clamps on and took them back off,, they clank,pop and hit stuff,and they cut your strut boot, (no room in echo chassis) Frank,, the race car builder does heat springs to adjust ride height,he builds them for a living, and races them,, he was ranked 27 nationally at one point ( all that does'nt mean he is the end all be all, thats why im on here consulting you guys, im having second thoughts about the lowering, anyway, but my main question is about the rake angle,, and if it would help. it will blunt the front windsheild, but help the rear a little and raise the rear decklid, could not live with the spring clamps long enough to test stuff.

Last edited by moonmonkey; 03-01-2010 at 10:07 PM.. Reason: puntuation
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Old 03-01-2010, 10:13 PM   #6 (permalink)
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Oh I see. Well several reputable sources say slight nose down is good for aero. Again, I doubt it will show up in tank-to-tank fe measurements but in the end it should marginally improve things.

As far as heating springs to lower them, I've never done it, mainly because I read so much recommending to not do it. When I lowered the Coupe I procured another set of stock springs, and set aside my originals in the event that I would be unhappy or otherwise fail somehow with the lowering experiment.
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Old 03-01-2010, 11:00 PM   #7 (permalink)
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I have first hand experience with "trying" to lower cars by heating springs. Didn't work for me - mine broke after weight was reapplied. You might get lucky, depending on how they are cooled and the material, but just willi-nilli going at them with a torch doesn't seem to agree with the collective experience base ;-)
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Old 03-01-2010, 11:10 PM   #8 (permalink)
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dont know how he does it, but he has never had one break, to his knowledge, maybe its techneque ,he wins races, and is locally well respected, but if i do it i might just use an air cutoff tool to cut them, so as not to take up his valuable time ,
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Old 03-02-2010, 12:16 AM   #9 (permalink)
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Quote:
Originally Posted by moonmonkey View Post
dont know how he does it, but he has never had one break, to his knowledge, maybe its techneque ,he wins races, and is locally well respected, but if i do it i might just use an air cutoff tool to cut them, so as not to take up his valuable time ,
That is a much safer approach, particularly if the ends don't need to be flattened.
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Old 03-02-2010, 02:14 AM   #10 (permalink)
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I'm with Frank.

Lowering your car by heating the springs is a bad idea. You're lowering the car not by fitting a shorter spring of equal (or higher) spring rate (which is the right way to do it), but by reducing your spring rate some unknown and uncontrollable amount. Your car already has soft springs, and heating them will soften them more (which isn't good for handling/safety).

Been there, done that, bought new springs.

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