Bushings
11-04-07, 01:56 AM
#1
Bushings
Many SCCA classes prohibit metal bushings; they also prohibit replacement bushings from having more metal content than stock. I'm looking at the Mazdatrix UHMW and Delrin bushings. Do our stock (FC) bushings have metal inner liners? I don't remember seeing them when I took my bushings off to replace them with polyurethane. I'm trying to find the stiffest bushings that are eligible under those SCCA rules.
11-04-07, 07:14 AM
#2
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You can run spherical bearings, needle bearings, delrin, or ? in ITS, suspension bushings are open. Motor, tranny, diff under debate but currently require OEM mounts. Which bushings specifically do you refer to? I might have a pair of spherical bearings for the rear out control arm pickup points available soon. Check AWR site for details.
11-04-07, 11:01 AM
#4
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IT rules are open.... run what you want.
"Bushing material, including that used to mount a suspension subframe to the chassis, is unrestricted. This includes the use of spherical bearings, so long as no suspension component is modified to facilitate their installation. Retention of spherical bearings by use of tack welds is allowed, as long as the welds serve no other purpose."
Just don't change the diff, tranny or motor mounts to anything but OEM.
Other suggestions if you want the best for bushings....
http://www.awrracing.com/store/produ...products_id=35
http://www.awrracing.com/store/produ...products_id=86
http://www.awrracing.com/store/produ...roducts_id=316
"Bushing material, including that used to mount a suspension subframe to the chassis, is unrestricted. This includes the use of spherical bearings, so long as no suspension component is modified to facilitate their installation. Retention of spherical bearings by use of tack welds is allowed, as long as the welds serve no other purpose."
Just don't change the diff, tranny or motor mounts to anything but OEM.
Other suggestions if you want the best for bushings....
http://www.awrracing.com/store/produ...products_id=35
http://www.awrracing.com/store/produ...products_id=86
http://www.awrracing.com/store/produ...roducts_id=316
11-06-07, 10:17 AM
#7
Lives on the Forum
Have a look at the rule book, but I don't think they're legal, you'd probably be stuck with Delrin or similiar. Although putting those in the rear control arms will mean that you can't use individual rear camber adusters.
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11-06-07, 10:22 AM
#8
They'll bind? If Delrin doesn't work, what's the stiffest bushing that will still comply with the individual adjusters?
The rule book was pretty much paraphrased in my first post but all the important parts were verbatim. I was hoping someone could look at the bushings and mounts (motor, tranny, diff, others) on that Mazdatrix page and see if they seem to have more or less metal than stock
The rule book was pretty much paraphrased in my first post but all the important parts were verbatim. I was hoping someone could look at the bushings and mounts (motor, tranny, diff, others) on that Mazdatrix page and see if they seem to have more or less metal than stock
11-06-07, 10:24 AM
#9
Eats, Sleeps, Dreams Rotary
Try reading the rule book... it'll tell you exactly what you need for the class you're trying to go for (which is primarily determined by your wheels and tires in the street classes, assuming you have no other mods).
IIRC, most street classes (except Stock, which doesn't technically even allow hardened rubber mounts, like the Mazdaspeed mounts which are OEM competition parts) allow any material but metal, but they have to be the same design.
On old cars (including FCs), you're also allowed to change the brake lines to stainless steel, IIRC... (maybe not in Stock, but in ST)
I think any commercially available polyurethane kit (like Energy Suspensions) will work fine, since I'm fairly sure the metal inserts are the same size as stock (and no one is going to check this anyway, except maybe at nationals... even the most **** regional people aren't going to make you take your car apart to prove the inserts are stock size).
Since it's a street car, you don't need to be using Delrin or metal mounts...
Just remember that if you're in ANY class but ST, the most important mod is R-compound tires, and R-compound tires alone. Nothing else matters nearly as much (although a bucket seat and harness help big time). And even in ST, the minimum tread wear is 140, which is very low compared to 99% of street tires.
IIRC, most street classes (except Stock, which doesn't technically even allow hardened rubber mounts, like the Mazdaspeed mounts which are OEM competition parts) allow any material but metal, but they have to be the same design.
On old cars (including FCs), you're also allowed to change the brake lines to stainless steel, IIRC... (maybe not in Stock, but in ST)
I think any commercially available polyurethane kit (like Energy Suspensions) will work fine, since I'm fairly sure the metal inserts are the same size as stock (and no one is going to check this anyway, except maybe at nationals... even the most **** regional people aren't going to make you take your car apart to prove the inserts are stock size).
Since it's a street car, you don't need to be using Delrin or metal mounts...
Just remember that if you're in ANY class but ST, the most important mod is R-compound tires, and R-compound tires alone. Nothing else matters nearly as much (although a bucket seat and harness help big time). And even in ST, the minimum tread wear is 140, which is very low compared to 99% of street tires.
11-06-07, 10:27 AM
#10
Eats, Sleeps, Dreams Rotary
FYI, the Mazdaspeed tranny mounts look exactly like the stock ones, the rubber is just 40% harder... and the only way to tell the difference would be to take them off and check the part number.
So consider this an undetectable mod, for all practical purposes.
I wouldn't hesitate to assume that the MS engine and diff mounts also look exactly the same (except the MS front diff mount doesn't have the weight, but you can attach the stock one).
So consider this an undetectable mod, for all practical purposes.
I wouldn't hesitate to assume that the MS engine and diff mounts also look exactly the same (except the MS front diff mount doesn't have the weight, but you can attach the stock one).
11-06-07, 10:28 AM
#11
.....that section is from the rule book.........
they also prohibit replacement bushings from having more metal content than stock
That's the key phrase. Do those Mazdatrix bushings in the link above, as well as bushings from AWR, like their urethane mounts and the like, qualify for that rule?
The car is in STS2, but will be towed to and from the track. Won't be seeing much, if any, street time if I can help it.
they also prohibit replacement bushings from having more metal content than stock
That's the key phrase. Do those Mazdatrix bushings in the link above, as well as bushings from AWR, like their urethane mounts and the like, qualify for that rule?
The car is in STS2, but will be towed to and from the track. Won't be seeing much, if any, street time if I can help it.
11-06-07, 12:12 PM
#13
I have all the Mazdaspeed mounts already, but I wanted to move to something more extreme, like the Delrin or UHMW mounts that Mazdatrix offers. That's why I wanted to check to see if anyone, could just visually inspect the pictures, to get an idea of if these bushings were legal under the no more metal than stock rule.
How are needle bearings compared with solid non-metallic bushings like delrin or uhmw?
Wow, I guess there really isn't an allowance for engine, tranny or diff mounts in ITS!
Sorry, for those ITS guys....what are you guys running to take advantage of the stayrod allowances? Specifically, the engine stayrod and the front stayrod?
And lastly, what about NASA unlimited?
How are needle bearings compared with solid non-metallic bushings like delrin or uhmw?
Wow, I guess there really isn't an allowance for engine, tranny or diff mounts in ITS!
Sorry, for those ITS guys....what are you guys running to take advantage of the stayrod allowances? Specifically, the engine stayrod and the front stayrod?
And lastly, what about NASA unlimited?
Last edited by Roen; 11-06-07 at 12:21 PM.
11-06-07, 12:19 PM
#14
Lives on the Forum
The stock ones do have metal in them, so any of the plastic or rubber replacements should be fine. The competition drivetrain mounts looke the same as the stock ones, no one will be able to tell just from looking at them.
The individual rear adjusters twist the control arm relative to the mounts, so basically you need a fairly soft bushing (stock) or get some spherical bearings like AWR sells. If you use hard bushings you'll be forcing rigid things to bend and that's not good. Even with fairly soft bushings it'll lead to some binding and stiction in the rear suspension. I wouldn't want to use any bushing other than the stock ones there, and even there I'm only using mine to even out the camber in the rear, not to take any out or add any in, that's what the subframe link is for.
The individual rear adjusters twist the control arm relative to the mounts, so basically you need a fairly soft bushing (stock) or get some spherical bearings like AWR sells. If you use hard bushings you'll be forcing rigid things to bend and that's not good. Even with fairly soft bushings it'll lead to some binding and stiction in the rear suspension. I wouldn't want to use any bushing other than the stock ones there, and even there I'm only using mine to even out the camber in the rear, not to take any out or add any in, that's what the subframe link is for.
11-06-07, 12:23 PM
#15
http://www.awrracing.com/store/produ...products_id=86
Looks good....
It's not the Mazda Comp mounts that I'm asking about, it's the Mazdatrix UHMW and Delrin mounts. I want to know that, just by looking at the pictures, can you tell if they have more metal than stock?
You wouldn't run polyurethane bushings in the rear with the individual control arm adjusters + adjustable subframe link?
Looks good....
It's not the Mazda Comp mounts that I'm asking about, it's the Mazdatrix UHMW and Delrin mounts. I want to know that, just by looking at the pictures, can you tell if they have more metal than stock?
You wouldn't run polyurethane bushings in the rear with the individual control arm adjusters + adjustable subframe link?
11-06-07, 07:12 PM
#16
Eats, Sleeps, Dreams Rotary
Why in God's name are you worrying about mounts?
If you've got the MS set, and you've got polyurethane suspension bushings, you're more than good enough for any sort of street class autocross use. It's a different story if you're making a pure race car, but not every autocross course is on super-smooth pavement... so why do you want a super-hard suspension?
Do you even have R-compound tires yet? If you don't, stop worrying about crap you don't need that's just going to make your car less fun to drive on the street (like solid mounts and rock-hard suspension bushings).
OTOH, if you're making a race car, you might as well get pillowball suspension bushings...
If you've got the MS set, and you've got polyurethane suspension bushings, you're more than good enough for any sort of street class autocross use. It's a different story if you're making a pure race car, but not every autocross course is on super-smooth pavement... so why do you want a super-hard suspension?
Do you even have R-compound tires yet? If you don't, stop worrying about crap you don't need that's just going to make your car less fun to drive on the street (like solid mounts and rock-hard suspension bushings).
OTOH, if you're making a race car, you might as well get pillowball suspension bushings...
11-06-07, 09:01 PM
#17
Why wouldn't I run stiffer bushings on a car that won't see street time? I mean, sure, there's a thing about not running super hard suspension, but that's mainly springs, shocks and sway bars. I would think the bushings have less of an impact than those three and more of an impact on transitional response.
I'm staying in street touring for budget reasons, but will be using R-comps in non-SCCA autocrosses.
I simply just wanted an answer to the question posed above....that's not so hard, is it?
I'm staying in street touring for budget reasons, but will be using R-comps in non-SCCA autocrosses.
I simply just wanted an answer to the question posed above....that's not so hard, is it?
11-06-07, 09:33 PM
#18
Eats, Sleeps, Dreams Rotary
If you're in ST, you're not allowed to use metal bushings or mounts.
If you want to use hard plastic ones, go for it. There's no REAL reason to if you already have hardened rubber or polyurethane ones, unless you just like the extra vibrations.
Why don't you just ask Mazdatrix if the inserts are the same size?
If you want to use hard plastic ones, go for it. There's no REAL reason to if you already have hardened rubber or polyurethane ones, unless you just like the extra vibrations.
Why don't you just ask Mazdatrix if the inserts are the same size?
11-06-07, 09:49 PM
#19
rx7 killer
11-06-07, 11:28 PM
#20
Eats, Sleeps, Dreams Rotary
They're just metal bushings with needle bearings.
Absolutely no play, but they're expensive, and obviously it's going to transmit every little bump in the road....
Absolutely no play, but they're expensive, and obviously it's going to transmit every little bump in the road....
11-07-07, 10:44 AM
#22
Lives on the Forum
I highly doubt that anyone has ever made a comparison gram for gram of the metal content in a delrin vs a stock bushing. The fact is the stock mounts have metal sleeves in them, and sometimes metal bands partway through to stiffen them, so any plastic mount with a reasonable size metal sleeve fits with the spirit of the rule so will be allowed. I don't think anyone expects you to be weiging them or anything.
Andy Hollis has delrin with metal sleeves in his multiple national tour winning car and no-one's protested him, and it's up on the Grassroots Motorsports website for anyone to see, so it's not exactly a secret.
Those AWR rear bearings are spherical, not needle, and they're probably going to be deemed illegal.
Andy Hollis has delrin with metal sleeves in his multiple national tour winning car and no-one's protested him, and it's up on the Grassroots Motorsports website for anyone to see, so it's not exactly a secret.
Those AWR rear bearings are spherical, not needle, and they're probably going to be deemed illegal.
