Dreaming of IRS
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Joined: Apr 2005
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Speaking of all this IRS...
Does anyone have the front suspension points and overall CG location?
This is very beneficial in choosing a suspension setup... Do they use underground or above ground roll centers.. what kind of Kingplin inclination, scrub radius... etc.
Does anyone have the front suspension points and overall CG location?
This is very beneficial in choosing a suspension setup... Do they use underground or above ground roll centers.. what kind of Kingplin inclination, scrub radius... etc.
While you're dreaming of IRS, why stop there? To really make it work effectively, you would probably need a completely new chassis design. So the best thing would be to to just gut your fbody and put it on a tube frame, but pick one that is designed to be mid-engined, so you have the LS1 right behind the front seats. You could even use the rear hatch for engine and transmission access. Then the car would have a true 50-50 weight distribution, as well as four wheel independant suspension.
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Joined: Apr 2005
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Originally Posted by Cal
While you're dreaming of IRS, why stop there? To really make it work effectively, you would probably need a completely new chassis design. So the best thing would be to to just gut your fbody and put it on a tube frame, but pick one that is designed to be mid-engined, so you have the LS1 right behind the front seats. You could even use the rear hatch for engine and transmission access. Then the car would have a true 50-50 weight distribution, as well as four wheel independant suspension.
FYI... a 50/50 weight distribution is not always optimal... especially on mid engined vehicles.. i have designed those vehicles.
And why we would stop there is because the IRS is somthing that could be accomplished without tearing the entire vehicle apart and focusing on one major performance hinderance of the design... and while your at it... why dont you just say that we should all be driving around Formula 1 cars... I appreciate the snide remarks.
Originally Posted by DanO
FYI... ... why dont you just say that we should all be driving around Formula 1 cars... I appreciate the snide remarks.
Originally Posted by DanO
why dont you just say that we should all be driving around Formula 1 cars....
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Thread Starter
TECH Fanatic
Joined: Nov 2004
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From: TX
Originally Posted by Cal
While you're dreaming of IRS, why stop there? To really make it work effectively, you would probably need a completely new chassis design. So the best thing would be to to just gut your fbody and put it on a tube frame, but pick one that is designed to be mid-engined, so you have the LS1 right behind the front seats. You could even use the rear hatch for engine and transmission access. Then the car would have a true 50-50 weight distribution, as well as four wheel independant suspension.
http://www.factoryfive.com/table/ffr...M/concept.html
Tube frame: Check
Mid-engined: Check
LS1: Check
50-50: Check
fully independent suspension: Check
Originally Posted by OldeSkool
FactoryFive took you up on your suggestion!
http://www.factoryfive.com/table/ffr...M/concept.html
Tube frame: Check
Mid-engined: Check
LS1: Check
50-50: Check
fully independent suspension: Check
http://www.factoryfive.com/table/ffr...M/concept.html
Tube frame: Check
Mid-engined: Check
LS1: Check
50-50: Check
fully independent suspension: Check
Last edited by Cal; Jul 27, 2005 at 12:33 AM.
[QUOTE=Cal]fbody was not designed to have a IRS, and it's unit body is not stressed for that. QUOTE]
That comment certainly isn't in the spirit of this board, or any one who's run the car hard on the street or strip. Look at all the sh*t people do to turn there street ready camaro and firebirds into to ***** to the wall drag cars. BBC and crazy small blocks with turbos, and sc's. Many pushing 600hp or way more....was the frame designed to take that stress? How much twist does that put on the chasis, frame, and the cars various other parts? No one hear thinks in terms of what it was designed to do, they want to see what it can be made to do, and how can I get it do it?
Granted an IRS in the fbody won't be as clean and smooth as ferrari, vette, porsche. I'm not asking it to be able to run 12 hours at sebring, or 24 hours at le mans. However, with a good welder, a shop that understand suspension geometry, and frame reinforcement it can be made to handle COMPETENTLY, functioning more than just eye candy. Atleast close to GTO and as well as the Cobra. You see these changes being made to trucks, hot rods, and older muscle cars.
http://www.classictrucksweb.com/tech/0303CT_IndThinkII/
http://www.rickroush.com/
http://www.waynedue.com/web/Products/irs.html
http://www.seattlestreetrods.com/index.htm
http://www.rodandcustommagazine.com/...279/index.html
http://www.pro-touring.com/waynedue/...rd_project.htm
That comment certainly isn't in the spirit of this board, or any one who's run the car hard on the street or strip. Look at all the sh*t people do to turn there street ready camaro and firebirds into to ***** to the wall drag cars. BBC and crazy small blocks with turbos, and sc's. Many pushing 600hp or way more....was the frame designed to take that stress? How much twist does that put on the chasis, frame, and the cars various other parts? No one hear thinks in terms of what it was designed to do, they want to see what it can be made to do, and how can I get it do it?
Granted an IRS in the fbody won't be as clean and smooth as ferrari, vette, porsche. I'm not asking it to be able to run 12 hours at sebring, or 24 hours at le mans. However, with a good welder, a shop that understand suspension geometry, and frame reinforcement it can be made to handle COMPETENTLY, functioning more than just eye candy. Atleast close to GTO and as well as the Cobra. You see these changes being made to trucks, hot rods, and older muscle cars.
http://www.classictrucksweb.com/tech/0303CT_IndThinkII/
http://www.rickroush.com/
http://www.waynedue.com/web/Products/irs.html
http://www.seattlestreetrods.com/index.htm
http://www.rodandcustommagazine.com/...279/index.html
http://www.pro-touring.com/waynedue/...rd_project.htm
Last edited by lees02WS6; Jul 27, 2005 at 08:48 AM. Reason: i can't spell
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IIRC, the test mule for the Cobra IRS development was a completed GT. A chassis that arguably "wasn't designed for the stresses of IRS". They didn't seem to have much problem. It just needs to be reinforced as and where necessary.
As for MR - I'll keep my engine upfront thanks. Shoot for 50/50, but not too worried if it's not dead on. The big weight towards the front makes it safer and easier to control once you go past the limit.
As for MR - I'll keep my engine upfront thanks. Shoot for 50/50, but not too worried if it's not dead on. The big weight towards the front makes it safer and easier to control once you go past the limit.
Originally Posted by HPP
IIRC, the test mule for the Cobra IRS development was a completed GT. A chassis that arguably "wasn't designed for the stresses of IRS". They didn't seem to have much problem. It just needs to be reinforced as and where necessary.
As for MR - I'll keep my engine upfront thanks. Shoot for 50/50, but not too worried if it's not dead on. The big weight towards the front makes it safer and easier to control once you go past the limit.
As for MR - I'll keep my engine upfront thanks. Shoot for 50/50, but not too worried if it's not dead on. The big weight towards the front makes it safer and easier to control once you go past the limit.
The Ford IRS is a complete unit. It's designed to place the chassis loads in the same locations as the solid axle setup. Therefore, it's heavy, a bit clunky and not really optimal, but it is independent (there is a 99 GT with an IRS swap that stays at my place....belongs to a room mate). It's not any worse than the solid axle, but I'm not sure how much better it is (than ours, not theirs. The stock GT suspension design sucks from a handling standpoint). It's a bandaid solution, but it's still better than what we got.
Last edited by trackbird; Jul 27, 2005 at 09:12 AM.
Originally Posted by lees02WS6
Originally Posted by Cal
fbody was not designed to have a IRS, and it's unit body is not stressed for that.
As far as running fbodys hard at the drag strip, that has been done since day one and by now everyone knows what works and what doesn't.
Originally Posted by Cal
I'm not saying that a good job could not be done with the hot-rodder's approach of "cut and try" and "modify what's already there." It just hasn't been done by very many people yet (if any) so this approach is going to take quite a few itterations to yield the best results.
As far as running fbodys hard at the drag strip, that has been done since day one and by now everyone knows what works and what doesn't.
As far as running fbodys hard at the drag strip, that has been done since day one and by now everyone knows what works and what doesn't.
I'm willing to take that approach, but testing whether it handles well or not is subjective. I'm not a good tester since I won't be pushing it like an autox'er would. You might drive it and think it's just adequate or less so.
Originally Posted by OldeSkool
For kicks I sent an e-mail to factoryfive asking about using GM specific parts in a cage designed for our cars. Pretty much what he said is they have no interest in taking on such a design. Oh well
Teching In
Joined: Jan 2005
Posts: 24
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From: Dallas, TX
Originally Posted by trackbird
The Ford IRS is a complete unit. It's designed to place the chassis loads in the same locations as the solid axle setup. Therefore, it's heavy, a bit clunky and not really optimal, but it is independent (there is a 99 GT with an IRS swap that stays at my place....belongs to a room mate). It's not any worse than the solid axle, but I'm not sure how much better it is (than ours, not theirs. The stock GT suspension design sucks from a handling standpoint). It's a bandaid solution, but it's still better than what we got.
Some people need to realize that IRS does not always equal better than a solid axle. There is a lot of design and actual engineering work to take place before you do it.
The cobra setup is probably an example of design to fit, but not necessarily be light or work well. IRS is a better setup for some and not for others depending on what you will be doing with it. There are some who would want it to be a perfect auto race piece, others would want it just for looks, and a lot in between who just want it to handle well on the street. And there are plenty of muscle car guys who just flat out think that IRS is voodoo, and sacreligous to put in a muscle car. Will it work well, who knows...I hope to find out by July '06.
Looks and status are one thing, but in racing it may or may not help. It will probably add weight if the car wasn't designed with it in mind to start with. That hurts racing performance. An IRS is adjustable, so you can add negative camber and toe in which will help on a road course. But if you don't wind up with a good camber curve, you could actually loose camber in a hard corner. Solid axles usually have zero camber, but they don't give up any under load either. Another thing is, you can bend a solid axle slightly to get up to -1.0 camber without affecting the reliability of the axle (quote from Herb Adams.) Likewise, you can bend the axle for a little toe-in to improve rear end stability in a corner.
I think someone did a irs in a 3rd gen I just cant find it but I know I saw it.. They used the c4 setup... I dont know alot about chassis related things and fabrication but I do know I ran across it.. If i find it Ill post it up for ya guys