STU: Understeer Understeer!! can you help ?
- 
trunk bar (cheap, helps keep your trunk from flexing)
- rear strut tower brace (I run the Cusco V-brace and am very happy with it)
- TRE rear diff upgrade (at $400 + shipping + labor to remove/install rear diff, it isn't super cheap, but man it does make a big difference)
trunk bar (cheap, helps keep your trunk from flexing)- rear strut tower brace (I run the Cusco V-brace and am very happy with it)
- TRE rear diff upgrade (at $400 + shipping + labor to remove/install rear diff, it isn't super cheap, but man it does make a big difference)
To the OP how experienced of a driver are you? Are you comfortable driving a tail happy car?
Given what you have you could try a few things. If the 1st one doesn't work, try the next thing down the list.
1. Stiffen the rear sway bar before the event to full stiff.
2. Change tire pressures in the rear, keep increasing the pressure until you get the desired amount of oversteer. Just don't go over the max limit.
3. Add some front toe-out to the front (beware this will eat your tires quickly)
Given your current setup you'll have to run 38-39 psi in the front to avoid the tire rolling onto its shoulder (bad). You could also get camber plates for the front and getting a little bit more -ve camber as others have suggested. It makes a world of difference.
PS: Jon needs to stop suggesting people cheat
First Let's attack some of the various mechanical reasons why the car is understeering beside driver induced push (braking too late, turn in with too much speed and getting back on the gas too soon)
1) Too much front roll
The front wheel rates are too low and the car and the car leans too much on the poor outside loaded tire that, at this point, is doing all the steering and accelarating. The solution is stiffening the front. This could be achieved 3 ways: a) stiffer front springs b) stiffer front bar c) a combination of both.
2) Not enough front camber
When the car is loaded in a turn, the camber loss due to the, not so great, MacPherson design causes the outside edge of front tire(I would aproximate only 1/3 of the satic contact patch is till on the ground) to do all the work.
The solution for this is obvious, run more static front camber. How much would depend on how stiff you go with springs/sway bars and a pyrometer is your best friend for this task.
3) Screwed suspension geometry due to lowering
Go too low and and the geometry of the front is all messed up, in some extreme cases roll center might end up subteranean.
The solution is to not lower the car too much or find a way to correct the roll center if you want to go low.
Remember, understeer is essentially a front problem on the evo and making the rear less grippy with a stiffer rear bar is a band aid, all it does is change the overall balance of the car and force it to oversteer before the still existent understeer happens. One of the evo's strongest point is the ability to get back on the gas earlier and explode out of corners because of the available rear grip, so let's not take that away from it. Other couple things that I found helpfull getting rid of the evo's push, but to a lesser degree was wider front stance
and more mechanical support (wider front rims) for the same size tire as the rear.
I am used to driving an SM2 mr2 (about 260whp) with race rubber. I could drift it /slither it/ or stick it. Depending on mood. I had no understeer only power induced oversteer. I can drive a car that is stepping out.
I had quite a bit of red mist. Seams like the faster the car is the harder this is for me to get a handle on.
I am running with Worx sprints which arent much of a drop. So the geometry is prolly OK.
Take a look at this:
This before the rear whiteline bar.
The next post will be the after (on medium)
I had quite a bit of red mist. Seams like the faster the car is the harder this is for me to get a handle on.
I am running with Worx sprints which arent much of a drop. So the geometry is prolly OK.
Take a look at this:
This before the rear whiteline bar.
The next post will be the after (on medium)
This is a similar hard turn on a less grippy surface:
https://www.evolutionm.net/forums/sh...d.php?t=344063
As you can see the bar seams to have allowed the rear inside wheel to to come up. and the front inside has marginally less wheel gap.
It still looks really bad. I am afraid that if I get the front bar I will push worse.
But assuming I can get the 'red mist' under control. It will still feel like I can go much faster.
I think UCP's are going to be required to get more tire on the ground from -2/0.
I guess I will try the easy stuff while I save the coin to get them...
https://www.evolutionm.net/forums/sh...d.php?t=344063
As you can see the bar seams to have allowed the rear inside wheel to to come up. and the front inside has marginally less wheel gap.
It still looks really bad. I am afraid that if I get the front bar I will push worse.
But assuming I can get the 'red mist' under control. It will still feel like I can go much faster.
I think UCP's are going to be required to get more tire on the ground from -2/0.
I guess I will try the easy stuff while I save the coin to get them...
Rear swaybars do not ONLY remove rear grip to cause oversteer. They do INCREASE front grip.
A given car in a given corner will experience a certain amount of total weight transfer. That total weight transfer will remain the same unless you change overall weight, or COG, or track width, and a few other variables. So spring rates and sway bars do not change overall total weight transfer, just how it occurs and at which end of the car it occurs (or it's distribution).
A stiffer rear bar will allow more weight transfer to occur at that end of the car, but since the total weight transfer must remain the same, you are then reducing the amount of weight transfer occurring at the front of the car, thereby INCREASING front grip due to having the front tires being more evenly loaded. Decreased weight transfer at that end of the car --> more even loading of tires --> more grip.
So....you may lose a small amount of rear grip from the rear bar due to the increased weight transfer at that end of the car, BUT remember, you are at the same time reducing roll in the rear, and maintaining dynamic camber throughout the turn. So you lose a little rear grip from the increased weight transfer but gain some back from the reduction in roll. AND at the same time, the front of the car is experiencing less weight transfer in the turn, increasing front grip.
I do agree with you that there is too much front roll....but you go on to recommend a front swaybar....by your definition wouldn't this just remove front grip? Everyone seems to say swaybars just remove grip....when in fact this is clearly not true. Yes, huge bars can ask too much from street tires, but the Whiteline bar is mild. And too stiff springs do the same thing.
A swaybar is just a spring that acts in one wheel bump.....don't overthink it.
Camber would definitely help as you said.
The springs in question are a pretty mild drop, less then an inch. 20mm up front.
I do think the first step should be the tire pressures, as that's a quick fix.
The ONLY reservation I would have about increasing the swaybar stiffness one notch is possibly lifting a rear wheel on tight corners.
And if you're lifting a rear wheel....it's certainly not from a lack of rear grip........
I also think a front bar will help, because I do not think Mitsubishi sized the OEM sway bars perfectly with auto-x in mind.
It may have a little more at the limit push, but the overall level of grip will be higher. It will also match the rear bar nicely and keep the inside rear tire on the ground. Not much fun to install though.I'm not flaming you....I enjoy discussion. The suspension forum can be slow, so this is nice.
- Andrew
Last edited by GTWORX.com; May 7, 2008 at 05:13 PM.
So I would first play with the tire pressures....change your driving style a little since an EVO is vastly different from a lightweight mid engine rear drive car. Just try the rear bar on the stiffer setting if you can't get where you want with just the tire pressures.
Then maybe get camber plates.
- Andrew
Then maybe get camber plates.
- Andrew
2 good posts from nasioc that i remember from 2005, the second one is clearer:
from this thread:
http://forums.nasioc.com/forums/showthread.php?t=879235
I believe most of nhluhr's info is from Milliken's books.
- Andrew
grip is defined as the ratio between traction and loading. When you increase loading, traction does increase, but not proportionally to the increase in load. The coefficient of friction is not constant for all loading values.
Therefore, if you have a tire with 700lbs loading and it produces a lateral traction of 700lbs, the grip is said to be 1.0. Increaase the loading to 1000 lbs and the traction will not increase to 1000... more like 900, with the grip now becoming 0.9.
Why this is important is the following:
If you have a pair of tires each loaded at 700lbs and a grip of 1.0 in this condition...This gives you 1400lbs of lateral traction.
Now enter a turn where you are transferring 100% of the weight to the outside tire. You now have the outside tire loaded to 1400lbs at a reduced grip ratio of ~0.85 and the inside tire loaded at 0lbs at a grip ratio of, say, 1.1. The total traction now is 1400(0.85) + 0(1.1) = 1190, a decrease in total traction.
The reason a large swaybar increases % of total weight transfer seen by the axle is as follows:
Total weight transfer does not change unless you reduce CG height, decrease lateral cornering force (either slow down, take a wider line, or decrease vehicle weight), or widen the track. Those are the only things that change the total lateral weight transfer. However, realize that the only thing resisting the total weight transfer is the roll stiffness of the front and rear suspensions. If one of them is noodle-soft and the other is very stiff, the car rolls X amount... if both are moderately stiff, the car rolls X amount. The one that is doing the majority of the roll resisting is going to putting the most pressure on its tires so that pair of tires will bear a larger portion of the total weight transfer.
Typically, when vehicle dynamics books mention changing swaybar sizes to affect over/understeer, they are really talking about keeping the same total roll stiffness, but putting more of it on the front or back to achieve the result. If you were to only change one bar, then the change in over/understeer bias is not as clearcut because you are changing the total roll stiffness instead of changing just the bias.
So, if you were to put a smaller rear bar on and increase the front bar the same amount, the result would be more understeer. BUT if you keep the rear bar the same and increase the front bar's size, you will end up with less roll and thus usually more traction. The reason for this is that camber has a much greater effect on grip than does loading... so the tradeoff of increasing tire loading is more-than-compensated-for by the drastic reduction in positive camber during cornering and the end result (on any car, not just an impreza) of just putting on a bigger bar, front or rear, is an increase in total traction.
Therefore, if you have a tire with 700lbs loading and it produces a lateral traction of 700lbs, the grip is said to be 1.0. Increaase the loading to 1000 lbs and the traction will not increase to 1000... more like 900, with the grip now becoming 0.9.
Why this is important is the following:
If you have a pair of tires each loaded at 700lbs and a grip of 1.0 in this condition...This gives you 1400lbs of lateral traction.
Now enter a turn where you are transferring 100% of the weight to the outside tire. You now have the outside tire loaded to 1400lbs at a reduced grip ratio of ~0.85 and the inside tire loaded at 0lbs at a grip ratio of, say, 1.1. The total traction now is 1400(0.85) + 0(1.1) = 1190, a decrease in total traction.
The reason a large swaybar increases % of total weight transfer seen by the axle is as follows:
Total weight transfer does not change unless you reduce CG height, decrease lateral cornering force (either slow down, take a wider line, or decrease vehicle weight), or widen the track. Those are the only things that change the total lateral weight transfer. However, realize that the only thing resisting the total weight transfer is the roll stiffness of the front and rear suspensions. If one of them is noodle-soft and the other is very stiff, the car rolls X amount... if both are moderately stiff, the car rolls X amount. The one that is doing the majority of the roll resisting is going to putting the most pressure on its tires so that pair of tires will bear a larger portion of the total weight transfer.
Typically, when vehicle dynamics books mention changing swaybar sizes to affect over/understeer, they are really talking about keeping the same total roll stiffness, but putting more of it on the front or back to achieve the result. If you were to only change one bar, then the change in over/understeer bias is not as clearcut because you are changing the total roll stiffness instead of changing just the bias.
So, if you were to put a smaller rear bar on and increase the front bar the same amount, the result would be more understeer. BUT if you keep the rear bar the same and increase the front bar's size, you will end up with less roll and thus usually more traction. The reason for this is that camber has a much greater effect on grip than does loading... so the tradeoff of increasing tire loading is more-than-compensated-for by the drastic reduction in positive camber during cornering and the end result (on any car, not just an impreza) of just putting on a bigger bar, front or rear, is an increase in total traction.
To address this, lets consider the explanation I just posted above....
1) Increasing just the front bar, the front tires see a larger percent of total weight transfer which increases front tire loading and reduces front tire grip slightly (and also the opposite effects on the rear tires)... BUT you also get a reduction in roll which reduces how positive your camber goes in hard cornering for a large increase in grip. The end result is a good increase in cornering grip with perhaps a very slightly higher bias towards understeer. Now, before a thousand people jump on that last statement, let me explain. I know that people are also putting on big front bars and saying "I got less understeer". I would contend that what their butt-dyno is telling them is not the whole truth. The real story is, the increased grip (from roll reduction) allowed them to go faster in places where they previously had understeer. So yes, perhaps they experience understeer less dramatically than before, but the bias has still shifted towards understeer more... it's just that the limits are now significantly higher so this bias is less apparent. I'd say that the front tires see a moderate gain in grip while the rear tires see a significant gain in grip.
2) Increasing just the rear bar, the rear tires will see a larger percent of the total weight transfer which increases rear tire loading (conversely taking load off the front tires) so you get a slight reduction in rear grip and a slight increase in front grip for a more oversteer-biased setup, but the decrease in lateral roll also increases total grip, just like above. The net change is more grip, more oversteer. I have heard a lot of people say "a rear bar increases oversteer by reducing rear traction". This is not exactly right. What it is doing is taking load off the front tires, thus increasing front traction where it is severely lacking, AND increasing load on the rear tires while also reducing roll. I would say that rear traction is increased marginally overall, while front traction is increased signifcantly.
3) Increasing both bars, you get double the reduction in roll and no real change in bias. This is the way to go, IMHO. You don't change the overall bias of the chassis, but you do vastly increase grip on both front and rear tires. I'd say that both front and rear tires see a significant increase in grip.
So, if I had to choose between 1) or 2), which would I choose? The decision would be based on a couple things, but lets say we are talking about a WRX sedan. The front is very heavy so front tire loading is already a problem... The torque bias is 50/50 so you have further load on the front tires. I would definitely choose the rear bar over the front bar if I was forced to choose only one. However, many autocrossers are limited to changing just the front bar, in which case, definitely do it. Any increase in overall grip you can get is an increase worth getting.
1) Increasing just the front bar, the front tires see a larger percent of total weight transfer which increases front tire loading and reduces front tire grip slightly (and also the opposite effects on the rear tires)... BUT you also get a reduction in roll which reduces how positive your camber goes in hard cornering for a large increase in grip. The end result is a good increase in cornering grip with perhaps a very slightly higher bias towards understeer. Now, before a thousand people jump on that last statement, let me explain. I know that people are also putting on big front bars and saying "I got less understeer". I would contend that what their butt-dyno is telling them is not the whole truth. The real story is, the increased grip (from roll reduction) allowed them to go faster in places where they previously had understeer. So yes, perhaps they experience understeer less dramatically than before, but the bias has still shifted towards understeer more... it's just that the limits are now significantly higher so this bias is less apparent. I'd say that the front tires see a moderate gain in grip while the rear tires see a significant gain in grip.
2) Increasing just the rear bar, the rear tires will see a larger percent of the total weight transfer which increases rear tire loading (conversely taking load off the front tires) so you get a slight reduction in rear grip and a slight increase in front grip for a more oversteer-biased setup, but the decrease in lateral roll also increases total grip, just like above. The net change is more grip, more oversteer. I have heard a lot of people say "a rear bar increases oversteer by reducing rear traction". This is not exactly right. What it is doing is taking load off the front tires, thus increasing front traction where it is severely lacking, AND increasing load on the rear tires while also reducing roll. I would say that rear traction is increased marginally overall, while front traction is increased signifcantly.
3) Increasing both bars, you get double the reduction in roll and no real change in bias. This is the way to go, IMHO. You don't change the overall bias of the chassis, but you do vastly increase grip on both front and rear tires. I'd say that both front and rear tires see a significant increase in grip.
So, if I had to choose between 1) or 2), which would I choose? The decision would be based on a couple things, but lets say we are talking about a WRX sedan. The front is very heavy so front tire loading is already a problem... The torque bias is 50/50 so you have further load on the front tires. I would definitely choose the rear bar over the front bar if I was forced to choose only one. However, many autocrossers are limited to changing just the front bar, in which case, definitely do it. Any increase in overall grip you can get is an increase worth getting.
http://forums.nasioc.com/forums/showthread.php?t=879235
I believe most of nhluhr's info is from Milliken's books.
- Andrew
Last edited by GTWORX.com; May 7, 2008 at 05:11 PM.
Evolving Member
Joined: Apr 2004
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From: Western North Carolina
I don't have a wealth of suspension tuning experience to draw on, and may not be able to offer specific advice to help your situation, but I do have some personal experience that may help.
I grew up driving high horsepower rwd cars, and gravitated to these kinds of cars in GT3 and GT4, having the most success with them and feeling at home. AWD cars felt awkward, and FWD cars made me feel like I couldn't drive. I had an early 80's Dodge Colt (Mitsubishi Mirage) Turbo, and that made me REALLY feel like I couldn't drive (for you younger kids, it was about 1800 lbs, 122 BHP, 140 ft-lbs of torque, through unequal length halfshafts to the fronts). In short, I hated FWD and could barely stand AWD.
Then I got an Evo 4 years ago specifically because it was AWD. I live in the mountains, and it snows. I loved being able to go in the snow, go in the rain, go on sand and dirt, just being able to go.
Then I started autocrossing it. As I gained confidence, I became frustrated with understeer. I battled it and battled it. It frustrated me.
Then I put on V710s and really battled it. Until I did two things.
1) I fiddled with tire pressures, and found they made a huge difference in handling balance.
2) I changed my driving style (probably the biggest factor) and used AWD's strengths instead of playing to its weaknesses (ie, not charging into tight corners).
I am competing locally against well-driven M3's and STi's with between $3,000 and $12,000 in mods and winning as often as I'm losing. I am in BSP by virtue of a flash and ACT clutch (whooopeee!!!) and, on the stock suspension, I can hang with the guys who have gone to coilovers, bumpsteer kits, MBC's, etc. All on a stock suspension.
Why the long novel? I am just suggesting that if you're second and you drive an Evo, you can be first simply by tightening the nut behind the wheel. The STi that I run most closely with is always changing his suspension settings, boost levels, DCCD settings, tire pressures, tires, etc. Sometimes he's faster than me, sometimes not. He's a very good driver, but when he goes out on a new course or surface, he seems lost. If the car doesn't handle the way he wants, he feels frustrated.
This has kept me from changing much except my driving; I don't like being frustrated, and I've had success by just changing the way I drive.
I think Andrew's suggestions are sound and I am actually considering camber plates myself. I know about where to set them, and I know what they should do. I'd suggest proceeding cautiously and getting lots of seat time before making any change, and avoid making multiple changes at once.
Last weekend, the STi guy decided his coilover settings were too stiff, so he was at the test and tune with me and decided to go back to full soft and adjust upward.
10 runs later, on R comps (I was on Advans), he was still 2.3 seconds behind me.
On a 21 second course.
Think before you buy.
For the short attention span folks:
Changing driving style = cheap and satisfying.
Changing parts may = frustration!
I grew up driving high horsepower rwd cars, and gravitated to these kinds of cars in GT3 and GT4, having the most success with them and feeling at home. AWD cars felt awkward, and FWD cars made me feel like I couldn't drive. I had an early 80's Dodge Colt (Mitsubishi Mirage) Turbo, and that made me REALLY feel like I couldn't drive (for you younger kids, it was about 1800 lbs, 122 BHP, 140 ft-lbs of torque, through unequal length halfshafts to the fronts). In short, I hated FWD and could barely stand AWD.
Then I got an Evo 4 years ago specifically because it was AWD. I live in the mountains, and it snows. I loved being able to go in the snow, go in the rain, go on sand and dirt, just being able to go.
Then I started autocrossing it. As I gained confidence, I became frustrated with understeer. I battled it and battled it. It frustrated me.
Then I put on V710s and really battled it. Until I did two things.
1) I fiddled with tire pressures, and found they made a huge difference in handling balance.
2) I changed my driving style (probably the biggest factor) and used AWD's strengths instead of playing to its weaknesses (ie, not charging into tight corners).
I am competing locally against well-driven M3's and STi's with between $3,000 and $12,000 in mods and winning as often as I'm losing. I am in BSP by virtue of a flash and ACT clutch (whooopeee!!!) and, on the stock suspension, I can hang with the guys who have gone to coilovers, bumpsteer kits, MBC's, etc. All on a stock suspension.
Why the long novel? I am just suggesting that if you're second and you drive an Evo, you can be first simply by tightening the nut behind the wheel. The STi that I run most closely with is always changing his suspension settings, boost levels, DCCD settings, tire pressures, tires, etc. Sometimes he's faster than me, sometimes not. He's a very good driver, but when he goes out on a new course or surface, he seems lost. If the car doesn't handle the way he wants, he feels frustrated.
This has kept me from changing much except my driving; I don't like being frustrated, and I've had success by just changing the way I drive.
I think Andrew's suggestions are sound and I am actually considering camber plates myself. I know about where to set them, and I know what they should do. I'd suggest proceeding cautiously and getting lots of seat time before making any change, and avoid making multiple changes at once.
Last weekend, the STi guy decided his coilover settings were too stiff, so he was at the test and tune with me and decided to go back to full soft and adjust upward.
10 runs later, on R comps (I was on Advans), he was still 2.3 seconds behind me.
On a 21 second course.
Think before you buy.
For the short attention span folks:
Changing driving style = cheap and satisfying.
Changing parts may = frustration!
You sound like Myles (my boss and the owner of GTWorx/Racecomp). Track instructor, racer, and engineer but very big on keeping it simple and not overthinking things. Seat time is the #1 mod.
I'm more of a numbers geek, but since he weighs 90lbs more then me and is still faster then me (only sometimes!) in a kart, I listen to him.
And sometimes being fast feels slow. Smoothness is key. Lots of drama isn't.
- Andrew
I'm more of a numbers geek, but since he weighs 90lbs more then me and is still faster then me (only sometimes!) in a kart, I listen to him.
And sometimes being fast feels slow. Smoothness is key. Lots of drama isn't.
- Andrew
Good points Andrew, however, Like you, I was once a proponent of the stiffer rear bar but testing lower times over a period of time proved the theory wrong for the particular evo platform.
This a picture of the modified bar I ran for over a season
The resulting reduction of rear grip and ending the luxury of being able to apply 100% throttle earlier than most platforms outwheighted any other possible gains of the the stiffer rear bar.
As you can see from the picure I posted, I modified the bars(drilled new holes) on both front and rear to allow modification at the track on the fly. The results just spoke for themselves. With two drivers over a period of half a season consitantly showing the same result of lower average(sometimes over a full second) lap times with the stiffer front bar and stock rear bar and all else being constant. Yes, we tryed every combinations and always stiffer rear/stock front< stiffer front and rear< stiffer front/ stock rear. Lap times, cornering G meter(only tried it for two events) and similar results found on another nationaly winning auto-x evo validated my conclusion.
Andrew, if anything, the stiffer front and rear combination felt the best to me but lap times showed their own story.
The logs also showed that the fastest times always comes from the lap with the highest average throttle application and the stock rear bar/stiffer front allowed us to do just that.
Another interesting point is that the stock front/rear bar and stiffer front/stock rear showed crossed talk between full throttle curve and lateral g curve, telling us that that full throttle was able to be applied while still cornering.
This a picture of the modified bar I ran for over a season
The resulting reduction of rear grip and ending the luxury of being able to apply 100% throttle earlier than most platforms outwheighted any other possible gains of the the stiffer rear bar.
As you can see from the picure I posted, I modified the bars(drilled new holes) on both front and rear to allow modification at the track on the fly. The results just spoke for themselves. With two drivers over a period of half a season consitantly showing the same result of lower average(sometimes over a full second) lap times with the stiffer front bar and stock rear bar and all else being constant. Yes, we tryed every combinations and always stiffer rear/stock front< stiffer front and rear< stiffer front/ stock rear. Lap times, cornering G meter(only tried it for two events) and similar results found on another nationaly winning auto-x evo validated my conclusion.
Andrew, if anything, the stiffer front and rear combination felt the best to me but lap times showed their own story.
The logs also showed that the fastest times always comes from the lap with the highest average throttle application and the stock rear bar/stiffer front allowed us to do just that.
Another interesting point is that the stock front/rear bar and stiffer front/stock rear showed crossed talk between full throttle curve and lateral g curve, telling us that that full throttle was able to be applied while still cornering.
Suprising that noone has even called into question the differences between driving an MR2 and Evo. AWD cars live or die by the phrase "slow in, fast out". if you feel like you cant push it faster into a corner, you cant. focus on braking smoother and later, and accelerationg out of the apex.
I think one of the things about the tire pressure that will help is the diference in pressure. I notice that 32/36 has +4 psi compared to 38/40 +2 psi. These tires are new for me so I will give it a try.
That was a nice read on the bars. With only 3 events in this car (3 diferent surfaces) I have alot to learn. 10 years of racing means I know what fast is. But I need to execute in an AWD. As I said before this car was absolutely a blast in the rain. I was normally smooth so 'rain dog' mode for means I am usually FTD even against awd's.
I am going to try to widen up my line and get more braking in and feel more for the apex's. The steady stat sweepers that my mr2 could destroy are actually a nemesis in this car as I feel I am gliding around them (one big apex) but I am on the edge at best and sliding at worst.
This is a great read btw.
That was a nice read on the bars. With only 3 events in this car (3 diferent surfaces) I have alot to learn. 10 years of racing means I know what fast is. But I need to execute in an AWD. As I said before this car was absolutely a blast in the rain. I was normally smooth so 'rain dog' mode for means I am usually FTD even against awd's.
I am going to try to widen up my line and get more braking in and feel more for the apex's. The steady stat sweepers that my mr2 could destroy are actually a nemesis in this car as I feel I am gliding around them (one big apex) but I am on the edge at best and sliding at worst.
This is a great read btw.
thatmr2guy wrote:
"As you can see the bar seams to have allowed the rear inside wheel to to come up. and the front inside has marginally less wheel gap."
Exactly, the stiffer rear bar promotes tripoding and once that wheel lives the ground the sway bar is useless and might as well be unbolted. The results is that you have to wait for the wheel to go back down then take set and finally you can get back on the gas. Not so good or fast proposition in my book.
"As you can see the bar seams to have allowed the rear inside wheel to to come up. and the front inside has marginally less wheel gap."
Exactly, the stiffer rear bar promotes tripoding and once that wheel lives the ground the sway bar is useless and might as well be unbolted. The results is that you have to wait for the wheel to go back down then take set and finally you can get back on the gas. Not so good or fast proposition in my book.
Good points Andrew, however, Like you, I was once a proponent of the stiffer rear bar but testing lower times over a period of time proved the theory wrong for the particular evo platform.
This a picture of the modified bar I ran for over a season
The resulting reduction of rear grip and ending the luxury of being able to apply 100% throttle earlier than most platforms outwheighted any other possible gains of the the stiffer rear bar.
As you can see from the picure I posted, I modified the bars(drilled new holes) on both front and rear to allow modification at the track on the fly. The results just spoke for themselves. With two drivers over a period of half a season consitantly showing the same result of lower average(sometimes over a full second) lap times with the stiffer front bar and stock rear bar and all else being constant. Yes, we tryed every combinations and always stiffer rear/stock front< stiffer front and rear< stiffer front/ stock rear. Lap times, cornering G meter(only tried it for two events) and similar results found on another nationaly winning auto-x evo validated my conclusion.
Andrew, if anything, the stiffer front and rear combination felt the best to me but lap times showed their own story.
The logs also showed that the fastest times always comes from the lap with the highest average throttle application and the stock rear bar/stiffer front allowed us to do just that.
Another interesting point is that the stock front/rear bar and stiffer front/stock rear showed crossed talk between full throttle curve and lateral g curve, telling us that that full throttle was able to be applied while still cornering.
This a picture of the modified bar I ran for over a season
The resulting reduction of rear grip and ending the luxury of being able to apply 100% throttle earlier than most platforms outwheighted any other possible gains of the the stiffer rear bar.
As you can see from the picure I posted, I modified the bars(drilled new holes) on both front and rear to allow modification at the track on the fly. The results just spoke for themselves. With two drivers over a period of half a season consitantly showing the same result of lower average(sometimes over a full second) lap times with the stiffer front bar and stock rear bar and all else being constant. Yes, we tryed every combinations and always stiffer rear/stock front< stiffer front and rear< stiffer front/ stock rear. Lap times, cornering G meter(only tried it for two events) and similar results found on another nationaly winning auto-x evo validated my conclusion.
Andrew, if anything, the stiffer front and rear combination felt the best to me but lap times showed their own story.
The logs also showed that the fastest times always comes from the lap with the highest average throttle application and the stock rear bar/stiffer front allowed us to do just that.
Another interesting point is that the stock front/rear bar and stiffer front/stock rear showed crossed talk between full throttle curve and lateral g curve, telling us that that full throttle was able to be applied while still cornering.
The main thing is that it can be made to work. Looks like you were on coilovers, and not knowing the rates or other info on them or the rates of the redrilled bars, there are some variables in there. And working with a mild lowering spring on the standard struts doesn't give you much to play with, so i think with the right set-up with the right swaybars you can definitely find some time. Swaybars are just springs in the end.
Suprising that noone has even called into question the differences between driving an MR2 and Evo. AWD cars live or die by the phrase "slow in, fast out". if you feel like you cant push it faster into a corner, you cant. focus on braking smoother and later, and accelerationg out of the apex.
- andrew