How to make an AWD car rotate
Dec 14, 2006, 08:51 AM
#46
Paul, Marty,
Do you guys have any ideas on the effects of more bias weight in the rear of an evo.... the weight distribution in the current evo is like 60/40. What would the car be like at 50/50? by moving the full weight battery to the trunk and adding a fuel cell, could that help?
I've been reading "Race Car Vehicle Dynamics" by William F. Milliken (bible for race engineers) and I’m trying to extract as much as possible from the evo with all kinds of techniques. Shock dampening is shown as a % of the vehicles overall characteristics... Milliken feels that the balance / weight placement / roll height / roll center / alignment and tires are most crucial to the vehicles ability to be neutral.
Possibly looking at the overall picture of the evo’s weight distribution might help.
I could be just talking out of my *** but I’m learning and I really like all the great input everyone has interjected.
-Kyle
Do you guys have any ideas on the effects of more bias weight in the rear of an evo.... the weight distribution in the current evo is like 60/40. What would the car be like at 50/50? by moving the full weight battery to the trunk and adding a fuel cell, could that help?
I've been reading "Race Car Vehicle Dynamics" by William F. Milliken (bible for race engineers) and I’m trying to extract as much as possible from the evo with all kinds of techniques. Shock dampening is shown as a % of the vehicles overall characteristics... Milliken feels that the balance / weight placement / roll height / roll center / alignment and tires are most crucial to the vehicles ability to be neutral.
Possibly looking at the overall picture of the evo’s weight distribution might help.
I could be just talking out of my *** but I’m learning and I really like all the great input everyone has interjected.
-Kyle
In Touring, you are not allowed to relocate the battery from stock location and it must remain OEM size. You can swap out the gas tank for a fuel cell but it has to be in the stock location as well. As far as roll height, some of the guys were able to come in 100lbs or so under the minimum weight and then put metal plates on the passenger side floor (which is the only place allowed per the rules) so you cant put the plates in the trunk to adjust the weight distribution, but you can put the spare tire back in. Its kinda funny in touring, the rules are designed to keep the costs down but in reality it has really aided the teams that can afford to pay people to be creative (custom valving etc..) and hurts those of us that cant afford 2k per strut (which is what im told the Suby struts cost). If they just said coilovers were allowed, you could go out spend under 4k and be right there with the top teams. They would never allow this in touring classes, but if they did the evo would likely benefit the most and would be the dominate car in the field.
Ill try to pick up his book, sounds interesting. Im sure all the theory is solid, the hard part is how he tells you how to achieve it while being hampered by Touring rules.
Last edited by Galant VR-4 #34; Dec 14, 2006 at 08:53 AM.
Dec 14, 2006, 08:59 AM
#47
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In Touring, you are not allowed to relocate the battery from stock location and it must remain OEM size. You can swap out the gas tank for a fuel cell but it has to be in the stock location as well. As far as roll height, some of the guys were able to come in 100lbs or so under the minimum weight and then put metal plates on the passenger side floor (which is the only place allowed per the rules) so you cant put the plates in the trunk to adjust the weight distribution, but you can put the spare tire back in. Its kinda funny in touring, the rules are designed to keep the costs down but in reality it has really aided the teams that can afford to pay people to be creative (custom valving etc..) and hurts those of us that cant afford 2k per strut (which is what im told the Suby struts cost). If they just said coilovers were allowed, you could go out spend under 4k and be right there with the top teams. They would never allow this in touring classes, but if they did the evo would likely benefit the most and would be the dominate car in the field.
Ill try to pick up his book, sounds interesting. Im sure all the theory is solid, the hard part is how he tells you how to achieve it while being hampered by Touring rules.
Ill try to pick up his book, sounds interesting. Im sure all the theory is solid, the hard part is how he tells you how to achieve it while being hampered by Touring rules.
-Kyle
Dec 14, 2006, 09:23 AM
#48
Russ, I just had all my stuff from Paul installed up at Ft Collins where they have all the crazy equipment for doing this stuff. They re-valve the Ohlins right there, so I'm sure you can still get it done. Paul himself doesn't do the re-valving, but his guys at CSU do it all the time. I can get you in touch with Robbie, the guy who worked with Joe and Paul from the beginning on all this stuff and who is still up there doing the re-valves on all the Vishnu Ohlins orders. He's a good guy and lives in Denver (his parents), so he's back and forth from there to Ft Collins.
Dec 14, 2006, 10:12 AM
#50
Pretty sure they can re-valve anything, and they have a shock dyno to verify everything as well as tons of shims, but I don't know how much they've done it with other shocks. My guess is they could do it no problem, but Joe or Paul would know for sure. I can also get you in touch with Robbie directly, since he does the re-valving himself.
Dec 14, 2006, 10:47 AM
#51
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I find it hard to believe that I have the only Evo that rotates easily...but we are usually trying to decrease oversteer in my car, not increase it.
VJ, a grand am driver, drove my car and thought it handled way too loose. But of course, then he saw how good our tire wear was in the 25 and understood the philosophy.
There's a couple of things you have to do to make the Evo handle right, but luckily none of them are very expensive, though you do have to face some compromises, especially in a street car.
Mostly, it comes down to careful spring selection, shock tuning, correcting the geometry, and playing with the diffs.
-dave
VJ, a grand am driver, drove my car and thought it handled way too loose. But of course, then he saw how good our tire wear was in the 25 and understood the philosophy.
There's a couple of things you have to do to make the Evo handle right, but luckily none of them are very expensive, though you do have to face some compromises, especially in a street car.
Mostly, it comes down to careful spring selection, shock tuning, correcting the geometry, and playing with the diffs.
-dave
Dec 14, 2006, 12:19 PM
#53
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I find it hard to believe that I have the only Evo that rotates easily...but we are usually trying to decrease oversteer in my car, not increase it.
VJ, a grand am driver, drove my car and thought it handled way too loose. But of course, then he saw how good our tire wear was in the 25 and understood the philosophy.
There's a couple of things you have to do to make the Evo handle right, but luckily none of them are very expensive, though you do have to face some compromises, especially in a street car.
Mostly, it comes down to careful spring selection, shock tuning, correcting the geometry, and playing with the diffs.
-dave
VJ, a grand am driver, drove my car and thought it handled way too loose. But of course, then he saw how good our tire wear was in the 25 and understood the philosophy.
There's a couple of things you have to do to make the Evo handle right, but luckily none of them are very expensive, though you do have to face some compromises, especially in a street car.
Mostly, it comes down to careful spring selection, shock tuning, correcting the geometry, and playing with the diffs.
-dave
Dec 14, 2006, 01:12 PM
#54
Dec 14, 2006, 01:44 PM
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Time to get creative...
Is T2 allowed to shim the rear diff?
An example of how to get around the rules from pro7 is that you are not allowed to remove the front sway bar if it rains. However, there is no rule against using extra long sway bar bolts and backing off on the nylocks until there is 2" of slop in the bolt...same thing, but within the rules.
Is T2 allowed to shim the rear diff?
An example of how to get around the rules from pro7 is that you are not allowed to remove the front sway bar if it rains. However, there is no rule against using extra long sway bar bolts and backing off on the nylocks until there is 2" of slop in the bolt...same thing, but within the rules.
Dec 14, 2006, 04:44 PM
#56
Time to get creative...
Is T2 allowed to shim the rear diff?
An example of how to get around the rules from pro7 is that you are not allowed to remove the front sway bar if it rains. However, there is no rule against using extra long sway bar bolts and backing off on the nylocks until there is 2" of slop in the bolt...same thing, but within the rules.
Is T2 allowed to shim the rear diff?
An example of how to get around the rules from pro7 is that you are not allowed to remove the front sway bar if it rains. However, there is no rule against using extra long sway bar bolts and backing off on the nylocks until there is 2" of slop in the bolt...same thing, but within the rules.
Last edited by meanmud; Dec 15, 2006 at 05:30 AM.
Dec 15, 2006, 10:18 AM
#59
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I'm running the same spring rates as many others, about 50 lbs heavier in the rear, and somewhere between 550lb and 800lb depending on tires, weather, driver, etc.
Shocks we have experimented with through the season have included JIC FLT A2, DMS50, KW, and Ohlins. All I can tell you about what we actually use is that they come from Robispec and changed depending on the track, driver, methodology, etc. At the end of the day, we found you can make any shock perform decently, but generally the more you spend the better it gets. You can't race competitively on a $2000 set of coilovers, but you also don't have to spend $10k on Penskes to make your car handle well.
There seems to be a number of products in the $3k to $6k range that all perform very well. Having a guy like Robert Fuller on board to help you meet your application and budget goals definitely helps save time, money, and frustration.
Shocks we have experimented with through the season have included JIC FLT A2, DMS50, KW, and Ohlins. All I can tell you about what we actually use is that they come from Robispec and changed depending on the track, driver, methodology, etc. At the end of the day, we found you can make any shock perform decently, but generally the more you spend the better it gets. You can't race competitively on a $2000 set of coilovers, but you also don't have to spend $10k on Penskes to make your car handle well.
There seems to be a number of products in the $3k to $6k range that all perform very well. Having a guy like Robert Fuller on board to help you meet your application and budget goals definitely helps save time, money, and frustration.
Dec 15, 2006, 01:30 PM
#60
Couple Pics from Runoffs
Keep in mind I just put the Ohlins on, no tuning and as it turned out I had 1.5 inchs LESS preload than stock up front. I have since fixed that issue and the car feels much better. Hmmmm obviously there Mr Clayton I am having technical difficulties 
There are 3 pictures there one looks damn small, but just Click on the pics and they will get up to size !!
Marty
There are 3 pictures there one looks damn small, but just Click on the pics and they will get up to size !!Marty
Last edited by Galant VR-4 #34; Dec 15, 2006 at 06:30 PM.