Advice setting up SM Evo
Sep 26, 2011, 11:06 PM
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Advice setting up SM Evo
Gents,
After years of working too hard in the field and never being home, I've finally landed a somewhat office job and am now able to make it to Auto-x events on weekends. The Evo has been a weekend car for several years now, and I've modded it with parts that I thought represented the best dollar/hp possible. I did this without any regards to SCCA classing or rules. As a result, I find myself in SM class thanks to any number of mods, but I don't really care about that. At any rate, an introduction to the car:
2003 Evo VIII GSR, 64K. Bought it brand new in 2003. Yes, old skool.
Mods:
Taipan (Vishnu) 3" TBE, Divorced WG O2 housing, Hollowed Cat
GSC S2 Cams
GSC Beehive Springs
AEM Tru-Time Cam Gears
Spoolinup COP
CBRD 3.8" Garrett Core FMIC
Perrin Intake and Filter
CBRD UICP and Batt Tray
AMS LICP
HKS GTII 7460, hand ported cold/hotside
JM Fab Exhaust Manifold, DEI Thermo Wrap/Spray
FIC High Imedance Injectors, 1100cc
AMS Fuel Rail
Cam Sensor Heat Shield
Clutch Pedal Stop
Works Throttle Body Gaskets
Denso IW22
AMS SS Fuel Hose
Saikou Michi Dual Catch Cans
Walbro 255
e85 Ethanol
I'm a little more than a mile above sea level, and the car is currently making around 400/400vhp, with fine tuning still in progress and hoping to squeeze some more ponies out, but that's besides the point of this thread. Bottom line is I have $6,187.05 invested in power mods on this car and I'm not changing them just to move into another auto-x classification. I'm a working stiff and bought many of the mods used off this forum at considerable savings, and I did all the installs myself.
Now on to Suspension:
Used MR Bilsteins with new Swift Spec-R springs ($619.00)
Stoptech 355mm BBK, used ($1100.00)
Axxis Ultimate Pads ($190.00)
Motul RBF600 ($15)
265/35/18 Advan Neova AD-07's ($698.66 on closeout from tirerack)
2 sets of 18x9 +31 offset wheels ($1600.00 SSR Comp and OEM R34 GTR takeoffs)
Lightweight Alum Lugnuts ($45)
Grand Total: $4,267.66
Everything else is stock: Stock clutch, stock trans, stock diffs, stock bushings, stock sways. So my suspension is basically a set of springs on OEM bilsteins, front BBK and couple year old max perf summer tires. I should also point out that this is my first season of auto-x, and I've attended 3 events so far. In that short time, my driving has improved dramatically, but I realize there is still some more time to be had by modding the driver. The course in my town is pretty big, with average times being 50-60 seconds based on course configuration. I'm the only Evo, so I don't really have much to compare to. Some comparo's here:
12 SM Chris B 2003 Mitsubishi EVO 52.316
17 BS-ST Paul D 2008 Subaru WRX STI 50.588
18 STR Jacob D 2000 Honda S2000 48.195
The STI is stock except for Kook RS-3's, driven by a very experienced driver, who also happens to be about 100lbs lighter than me. This tells me I should be able to scratch out another 2 seconds with more driving experience. The S2000 is a nationally competitive one, with a national caliber driver, on full coils and all the goodies running Z1 star specs. He's like 150 lbs lighter than me, and his car is even lighter than my Evo. At the scales, my Evo weighed 3180 # with 3/8 tank of gas and no driver. I weigh 255 # and could probably use a PS3-like stage 4 weight reduction, but it's not as easy as the videogames, so let's stay on track with reality. That brings total vehicle weight to 3450 # +/-, based on about a half tank of gas.
Now, being an Alpha type, I hate not winning. But being a broke, working class SOB, I realize I must spend wisely or else my wife will have to counterbalance with excessive trips to DSW, and I just can't afford that. So, my goal then, this winter, is to maximize my grip/dollar in suspension modifications. I will attempt to scour up as many good deals in the FS/trade section, but I need help prioritizing my build and parts list. So, getting to the end of this diatribe, here's what I'm thinking, in order of most grip/dollar to least.
1) TRE max-lock diff rebuild $375.00
2) Adj Rear Sway Bar $188.00
3) Roll Center Kit $176.99
4) Bump Steer bushings $73.00
5) Rear Trailing arm bushing $112.00
4+5 Alternative? Energy Master kit for $136.99...any pro's con's vs. whiteline???
6) Alignment, but what specs? $140.00
7) Binary Seat Lowering kit $130.00
8) 4 point harnesses $170.00
Grand Total: $1,364.00
I've purposely avoided the "Yo what coilovers should I get for $800" routine, as I've been around here long enough to know better. I will keep my eye out for some used Ohlins, Motons, Penske's, AST's or the like, but those are becoming rarer and rarer in the FS section these days. The car is not a daily driver, but at the same time, the roads up here in NW New Mexico are awful, which is why pretty much everyone drives a pickup. I'm not afraid of a firm ride, but JDM insane spring rates won't fly as I'm a little too old to enjoy pogo sticking down the road anymore. And since many of the Auto-x events are 3-5 hours drive from here, those treks need to be able to have me arrive without pissing blood. I do also have some pretty scenic drives nearby (million dollar hwy anyone?) that I enjoy driving as well.
So, getting to the end of this novel; thoughts? opinions? Is my list jacked? Out of order? Anything I'm missing, left out? Experienced input would be much obliged. And the dude will abide.
After years of working too hard in the field and never being home, I've finally landed a somewhat office job and am now able to make it to Auto-x events on weekends. The Evo has been a weekend car for several years now, and I've modded it with parts that I thought represented the best dollar/hp possible. I did this without any regards to SCCA classing or rules. As a result, I find myself in SM class thanks to any number of mods, but I don't really care about that. At any rate, an introduction to the car:
2003 Evo VIII GSR, 64K. Bought it brand new in 2003. Yes, old skool.
Mods:
Taipan (Vishnu) 3" TBE, Divorced WG O2 housing, Hollowed Cat
GSC S2 Cams
GSC Beehive Springs
AEM Tru-Time Cam Gears
Spoolinup COP
CBRD 3.8" Garrett Core FMIC
Perrin Intake and Filter
CBRD UICP and Batt Tray
AMS LICP
HKS GTII 7460, hand ported cold/hotside
JM Fab Exhaust Manifold, DEI Thermo Wrap/Spray
FIC High Imedance Injectors, 1100cc
AMS Fuel Rail
Cam Sensor Heat Shield
Clutch Pedal Stop
Works Throttle Body Gaskets
Denso IW22
AMS SS Fuel Hose
Saikou Michi Dual Catch Cans
Walbro 255
e85 Ethanol
I'm a little more than a mile above sea level, and the car is currently making around 400/400vhp, with fine tuning still in progress and hoping to squeeze some more ponies out, but that's besides the point of this thread. Bottom line is I have $6,187.05 invested in power mods on this car and I'm not changing them just to move into another auto-x classification. I'm a working stiff and bought many of the mods used off this forum at considerable savings, and I did all the installs myself.
Now on to Suspension:
Used MR Bilsteins with new Swift Spec-R springs ($619.00)
Stoptech 355mm BBK, used ($1100.00)
Axxis Ultimate Pads ($190.00)
Motul RBF600 ($15)
265/35/18 Advan Neova AD-07's ($698.66 on closeout from tirerack)
2 sets of 18x9 +31 offset wheels ($1600.00 SSR Comp and OEM R34 GTR takeoffs)
Lightweight Alum Lugnuts ($45)
Grand Total: $4,267.66
Everything else is stock: Stock clutch, stock trans, stock diffs, stock bushings, stock sways. So my suspension is basically a set of springs on OEM bilsteins, front BBK and couple year old max perf summer tires. I should also point out that this is my first season of auto-x, and I've attended 3 events so far. In that short time, my driving has improved dramatically, but I realize there is still some more time to be had by modding the driver. The course in my town is pretty big, with average times being 50-60 seconds based on course configuration. I'm the only Evo, so I don't really have much to compare to. Some comparo's here:
12 SM Chris B 2003 Mitsubishi EVO 52.316
17 BS-ST Paul D 2008 Subaru WRX STI 50.588
18 STR Jacob D 2000 Honda S2000 48.195
The STI is stock except for Kook RS-3's, driven by a very experienced driver, who also happens to be about 100lbs lighter than me. This tells me I should be able to scratch out another 2 seconds with more driving experience. The S2000 is a nationally competitive one, with a national caliber driver, on full coils and all the goodies running Z1 star specs. He's like 150 lbs lighter than me, and his car is even lighter than my Evo. At the scales, my Evo weighed 3180 # with 3/8 tank of gas and no driver. I weigh 255 # and could probably use a PS3-like stage 4 weight reduction, but it's not as easy as the videogames, so let's stay on track with reality. That brings total vehicle weight to 3450 # +/-, based on about a half tank of gas.
Now, being an Alpha type, I hate not winning. But being a broke, working class SOB, I realize I must spend wisely or else my wife will have to counterbalance with excessive trips to DSW, and I just can't afford that. So, my goal then, this winter, is to maximize my grip/dollar in suspension modifications. I will attempt to scour up as many good deals in the FS/trade section, but I need help prioritizing my build and parts list. So, getting to the end of this diatribe, here's what I'm thinking, in order of most grip/dollar to least.
1) TRE max-lock diff rebuild $375.00
2) Adj Rear Sway Bar $188.00
3) Roll Center Kit $176.99
4) Bump Steer bushings $73.00
5) Rear Trailing arm bushing $112.00
4+5 Alternative? Energy Master kit for $136.99...any pro's con's vs. whiteline???
6) Alignment, but what specs? $140.00
7) Binary Seat Lowering kit $130.00
8) 4 point harnesses $170.00
Grand Total: $1,364.00
I've purposely avoided the "Yo what coilovers should I get for $800" routine, as I've been around here long enough to know better. I will keep my eye out for some used Ohlins, Motons, Penske's, AST's or the like, but those are becoming rarer and rarer in the FS section these days. The car is not a daily driver, but at the same time, the roads up here in NW New Mexico are awful, which is why pretty much everyone drives a pickup. I'm not afraid of a firm ride, but JDM insane spring rates won't fly as I'm a little too old to enjoy pogo sticking down the road anymore. And since many of the Auto-x events are 3-5 hours drive from here, those treks need to be able to have me arrive without pissing blood. I do also have some pretty scenic drives nearby (million dollar hwy anyone?) that I enjoy driving as well.
So, getting to the end of this novel; thoughts? opinions? Is my list jacked? Out of order? Anything I'm missing, left out? Experienced input would be much obliged. And the dude will abide.
Sep 27, 2011, 07:32 AM
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I have lots of thoughts. And lots of opinions. You are on the right track, in that you need to work on your driving. Ultimately, it depends on how competitive you want to be.
To be nationally competitive, your car will be barely liveable on the street. Super high spring rates, missing creature comforts, etc. Not to say it can't be done.
Anyway, I wouldn't waste your time on any of the mods you listed except for maybe the harness. But on street tires, the stock belts should be good enough.
My suggestion for you is to purchase a set of fresh street tires. The hancooks are a good option. And the 265's fit nicely on a 18x9. ( My daily driver setup).
Get as much seat time as possible. Once you've burned through that next set of tires. Then you can look at getting some quality coilovers an some big wheels and rubber.
Right now, the car would be faster with those changes, but you won't.
P.S. There are lots of cool guys in your region. Have them ride with you. And if you can, have them co-drive with you.
To be nationally competitive, your car will be barely liveable on the street. Super high spring rates, missing creature comforts, etc. Not to say it can't be done.
Anyway, I wouldn't waste your time on any of the mods you listed except for maybe the harness. But on street tires, the stock belts should be good enough.
My suggestion for you is to purchase a set of fresh street tires. The hancooks are a good option. And the 265's fit nicely on a 18x9. ( My daily driver setup).
Get as much seat time as possible. Once you've burned through that next set of tires. Then you can look at getting some quality coilovers an some big wheels and rubber.
Right now, the car would be faster with those changes, but you won't.
P.S. There are lots of cool guys in your region. Have them ride with you. And if you can, have them co-drive with you.
Sep 27, 2011, 07:44 AM
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On 2nd thoughts. I would recommend the diff mod. The car sucks without it.
Also, i don't necessarily think going with cheap coilovers is a bad idea. The stock suspension is just plain horrible for autox. And I feel it would be an easier progression going from
Stock>cheap>AST setup Vs. Stock>AST.
The car is very different and actually easier to driver on coilovers. Despite what many people here think, cheapo coilovers are not THAT much slower than the big dollar stuff. (I run AST's FYI)
But even the cheap ones will help you lower the car and up the spring rates. You can run big front and rear bars to mimic stiffer springs without hurting ride quality as much too.
Also, i don't necessarily think going with cheap coilovers is a bad idea. The stock suspension is just plain horrible for autox. And I feel it would be an easier progression going from
Stock>cheap>AST setup Vs. Stock>AST.
The car is very different and actually easier to driver on coilovers. Despite what many people here think, cheapo coilovers are not THAT much slower than the big dollar stuff. (I run AST's FYI)
But even the cheap ones will help you lower the car and up the spring rates. You can run big front and rear bars to mimic stiffer springs without hurting ride quality as much too.
Sep 27, 2011, 09:43 AM
#4
I think the tires are the biggest factor in where your path takes you. that said regardless of what tires you run an alignment, the tre diff and rear swaybar are GREAT investments. if you plan to stick with non r-comps the need to go to super high spring rates isn't nearly as strong. the bushings/roll center/bump steer stuff is more icing on the cake type stuff, none of them are really 'must haves'. The roll center kit is probably highest on my list out of those and the bump steer kit the lowest.
if you go with r-comps then the priority list changes and coilovers probably jump to number 3 after the RSB and diff. Bushings will be much more important with the increased grip. as will the roll center correction kit once you have the coilovers on and the car slammed.
on my street car i have 1,2,5,6,7 from you list, with stock springs and stock kyb shocks and it's pretty damn fun.
if you go with r-comps then the priority list changes and coilovers probably jump to number 3 after the RSB and diff. Bushings will be much more important with the increased grip. as will the roll center correction kit once you have the coilovers on and the car slammed.
on my street car i have 1,2,5,6,7 from you list, with stock springs and stock kyb shocks and it's pretty damn fun.
Sep 27, 2011, 01:13 PM
#6
I ran a pretty similar setup suspension wise as you for a set of tires (Hankook 245 z214's). The front has far to much roll and kills the outer edge so I would personally move a front swaybar to the top of your list. Pain in the *** to install, but made a massive difference with mid-corner understeer.
When I swapped to the TRE diff I ended up going back to the stock rear diff to get the back to not oversteer as much. Ended up being to tail happy and I lost too much time trying to get it to stay in place on corner-entry/mid-corner.
Trailing arm bushings are a definite must also, with you're power level you are crushing them on acceleration possibly killing corner exit rotation.
So, FSB, Rear Diff, Trailing bushing, Hankook RS-3's... Then just drive like 10+ events with that config and get instructors to ride with you. My opinion of course.
When I swapped to the TRE diff I ended up going back to the stock rear diff to get the back to not oversteer as much. Ended up being to tail happy and I lost too much time trying to get it to stay in place on corner-entry/mid-corner.
Trailing arm bushings are a definite must also, with you're power level you are crushing them on acceleration possibly killing corner exit rotation.
So, FSB, Rear Diff, Trailing bushing, Hankook RS-3's... Then just drive like 10+ events with that config and get instructors to ride with you. My opinion of course.
Sep 27, 2011, 05:42 PM
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It sounds like you were getting on the gas either too soon or too hard. Just because you have AWD doesn't mean you can stomp on the gas whenever you want.
The diff should allow you to power out of most corners with a more neutral to mild-oversteer vs a whole lotta push.
Sep 27, 2011, 05:46 PM
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I'd rather take a bone stock car with cheapo coilovers over your setup and I bet it would be faster on course. As you mentioned, things like a RSB, roll center kit are all just extras. Not primary changes.
Sep 27, 2011, 06:39 PM
#10
Please don't take this as anything but friendly advice.
It sounds like you were getting on the gas either too soon or too hard. Just because you have AWD doesn't mean you can stomp on the gas whenever you want.
The diff should allow you to power out of most corners with a more neutral to mild-oversteer vs a whole lotta push.
It sounds like you were getting on the gas either too soon or too hard. Just because you have AWD doesn't mean you can stomp on the gas whenever you want.
The diff should allow you to power out of most corners with a more neutral to mild-oversteer vs a whole lotta push.
Sep 27, 2011, 07:07 PM
#11
To be fastest with the least amount of $$:
1 - anything you can do to get more front camber (cheap coilovers, camber bolts, modify OEM shocks, camber plates for oem shocks)
2 - stiffer front swaybar (recommend Tanabe) with Cusco FSB adjustment brackets
3 - stiffer adjustable rear swaybar with endlinks (recommend Perrin for both)
4 - used Kumho V710 or Hoosier A6's (will be faster than street tires, but a HUGE PITA needing to haul them to the race then swap them on and off at every event. If you don't want to deal with that get the Hankook, StarSpec, or AD08)
5 - TRE Maxlock rear diff with side-diff cover
Of course all just IMHO, but all the recommendations thus far would give great results. . .
1 - anything you can do to get more front camber (cheap coilovers, camber bolts, modify OEM shocks, camber plates for oem shocks)
2 - stiffer front swaybar (recommend Tanabe) with Cusco FSB adjustment brackets
3 - stiffer adjustable rear swaybar with endlinks (recommend Perrin for both)
4 - used Kumho V710 or Hoosier A6's (will be faster than street tires, but a HUGE PITA needing to haul them to the race then swap them on and off at every event. If you don't want to deal with that get the Hankook, StarSpec, or AD08)
5 - TRE Maxlock rear diff with side-diff cover
Of course all just IMHO, but all the recommendations thus far would give great results. . .
Sep 27, 2011, 11:44 PM
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Right, so it seems that we are reaching a bit of consensus among the gallery. I shall therefore revise my original list some:
1) TRE max-lock diff rebuild $375.00 (Almost Universally Approved)
2) Eccentric front camber bolts $40? (Cheap, and more front grip always helps)
3) Larger FRONT Sway bar $TBD (more on this below)
4) Adj Rear Sway Bar $188 (Didn't Swift make a combo set once upon a time?)
5) Endlinks that don't clunk $TBD (Need to research best option, Perrin recommended)
Then in order of mixed preference:
Roll Center Kit $176.99
Bump Steer bushings $73.00
Rear Trailing arm bushing $112.00
Alignment, but what specs? $140.00
Binary Seat Lowering kit $130.00
4 point harnesses $170.00
My justification for the above is the following: car is lowered, RCK helps normalize susp geometry. Bump steer and RTA bushings seem to be deemed as biggest squish points in stock susp that relate to keeping said geometry optimal. Alignment is needed after bushings and to take advantage of eccentric camber bolts. Binary seat lowering kit will lower my fat *** quite a bit. If the MR aluminum roof worked for Mitsu, this has gotta work for me.
And lastly, 4 point harnesses because I'm tired of locking my seatbelt and pulling seat forward. And besides, I scored a used Sparco Harness bar for $150...
Now, as far as the recommendations for FRONT vs. rear sway bar, I need to go back and find an old thread I remember from back in the days. I seem to recall an excellent discussion on the merits of not using a rear sway bar by Paul Gerrard and whomever he had revalving his Ohlins. I believe it was a school in CO somewhere. I do realize that the RSB ultimately decreases rear grip, which is not ideal, but helps the car rotate more evenly. I also believe this was before the stock rear diff was being rebuilt, though I can't remember if Paul's car was running a modified rear diff. Will check in on that.
Also, slicks aren't really an option. Time is precious, I'm lazy, and carting around dirty tires in the evo and changing them in a parking lot is not my idea of fun. Yes, I know that is the cheapest way to drop time, but I'm not that dedicated. That and it would exaggerate my inadequate spring rates. I realize my AD-07's are several years old tech, but they were cheap and still have treadlife left on them. Once worn out I think I'll go with the Star Specs or RS3's unless I can find the AD08's for a deal, since they seem to be somewhat more costly.
I've ridden with several of the faster guys and had them ride along with me. So far my biggest opportunities for improvement lie in setting myself up for slaloms better (working on aiming inside rear tire at cones) and realizing when I can go flat and hold it, as well as braking in time so as not too plough past apexes. I'm interested in datalogging so I can see and quantify improvements, understand MaxQ is out, does Racelogic have a reasonably priced Auto-x logger? All in all, I realize more seat time can conceivably yield more grip/$, but there's no events in the winter and I may as well do whatever I can to make the car more potent once my ability catches up.
1) TRE max-lock diff rebuild $375.00 (Almost Universally Approved)
2) Eccentric front camber bolts $40? (Cheap, and more front grip always helps)
3) Larger FRONT Sway bar $TBD (more on this below)
4) Adj Rear Sway Bar $188 (Didn't Swift make a combo set once upon a time?)
5) Endlinks that don't clunk $TBD (Need to research best option, Perrin recommended)
Then in order of mixed preference:
Roll Center Kit $176.99
Bump Steer bushings $73.00
Rear Trailing arm bushing $112.00
Alignment, but what specs? $140.00
Binary Seat Lowering kit $130.00
4 point harnesses $170.00
My justification for the above is the following: car is lowered, RCK helps normalize susp geometry. Bump steer and RTA bushings seem to be deemed as biggest squish points in stock susp that relate to keeping said geometry optimal. Alignment is needed after bushings and to take advantage of eccentric camber bolts. Binary seat lowering kit will lower my fat *** quite a bit. If the MR aluminum roof worked for Mitsu, this has gotta work for me.
And lastly, 4 point harnesses because I'm tired of locking my seatbelt and pulling seat forward. And besides, I scored a used Sparco Harness bar for $150...Now, as far as the recommendations for FRONT vs. rear sway bar, I need to go back and find an old thread I remember from back in the days. I seem to recall an excellent discussion on the merits of not using a rear sway bar by Paul Gerrard and whomever he had revalving his Ohlins. I believe it was a school in CO somewhere. I do realize that the RSB ultimately decreases rear grip, which is not ideal, but helps the car rotate more evenly. I also believe this was before the stock rear diff was being rebuilt, though I can't remember if Paul's car was running a modified rear diff. Will check in on that.
Also, slicks aren't really an option. Time is precious, I'm lazy, and carting around dirty tires in the evo and changing them in a parking lot is not my idea of fun. Yes, I know that is the cheapest way to drop time, but I'm not that dedicated. That and it would exaggerate my inadequate spring rates. I realize my AD-07's are several years old tech, but they were cheap and still have treadlife left on them. Once worn out I think I'll go with the Star Specs or RS3's unless I can find the AD08's for a deal, since they seem to be somewhat more costly.
I've ridden with several of the faster guys and had them ride along with me. So far my biggest opportunities for improvement lie in setting myself up for slaloms better (working on aiming inside rear tire at cones) and realizing when I can go flat and hold it, as well as braking in time so as not too plough past apexes. I'm interested in datalogging so I can see and quantify improvements, understand MaxQ is out, does Racelogic have a reasonably priced Auto-x logger? All in all, I realize more seat time can conceivably yield more grip/$, but there's no events in the winter and I may as well do whatever I can to make the car more potent once my ability catches up.
Sep 27, 2011, 11:59 PM
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Well, I found part of what I was looking for: Re-Quoted Paul since this is pertinent to this discussion and he knows what he's talking about.
The things to remember are that this is not a black and white issue and it won’t be cured with just anti-roll-bars. Just to focus on the Evo's glaring problem; it’s the weight distribution, at 60f/40r your mid-corner speed is going to suffer and understeer will always be a problem. That means the driver can use various tools (adjust driving technique) to minimize the problem BUT if the corner has any sustained (steady state) cornering the understeer is going to rear it's ugly head no matter how good the driver is (Mark!). This understeer can be described as the front tires at maximum lateral grip (slip angle) and the rear tires significantly below their max (properly driven). This is why it's slow at this point in the corner. Picture now a BMW M3 at the same corner and for the sake of this comparison it has the exact same tire size and type as the EVO (we know it doesn’t in real life). Except the BMW has 50/50 weight distribution. At the same sustained mid-corner phase as the EVO it is balanced with equal load on both "axles" (fr/r). Front ties at 100% REAR @ 100% = higher corner speeds due to the better balance and maximizing all tires.
So how do we fix the EVO? First realize it will never have the mid-corner speed of the BMW but don't worry it doesn’t have to be faster! We do want to optimize mid-corner speed by INCREASING front end grip but to go faster we also need to take advantage of the AWD system on the way out and the weight bias on the way in.
As we discussed above the more weight you have towards the rear (up to 50%) the higher your mid-corner speed will be but...but the more spin prone you car will be on entry! So we can be faster than the M3 from turn in to apex. We can brake later and carry more brake into the corner (yes the infamous "trail braking"). On the way out of the turn (described as when you start to unwind the wheel) we can (if you lined the car up properly with the trail brake in the turn-in the phase) progressively get into the power and put it down more efficiently than the M3. Our line (path through the corner) should minimize time spent at steady-state, which means a generally later apex that the M3. That's how a 271hp well driven EVO can beat a 333hp M3 as long as the course is not a skidpad or a bunch of connected steady state corners.
Now about mid-corner speeds. There are two ways to increase overall grip, one is easy and get you a small increase the other is much more complicated but the car is much faster after all that hard work and $$$. BTW we have talked about this all before so I apologize to all that are experiencing a sense of Deja' Vu right know
1. Easy way: reduce rear grip to balance (by putting on a bigger rear bar and/or increasing rear tire pressure reducing rear toe etc.). This will actually make your mid-corner speed slightly higher but where the speed increase comes from is how much more efficiently you can "rotate" the car on the brakes during corner entry and therefore open the wheel up sooner (therefore get on the gas sooner etc.). So yes you have slightly increase overall grip (witness the higher skidpad number over stock) but the car could be faster still…
2. Proper way: increase front grip to balance the car. Simple things; lower the front relative to the rear, widen front track (this can be overdone and increase understeer if geometry issues are not accounted for), increase spring rate (front) so we can soften the front bar and reduce lateral load transfer, increase rebound (front). More complicated things...measure bump-steer up front then fix issues and optimize alignment specs (through testing). Notice that it is all done at the front (there is nothing wrong with the back!). There is more but it requires a shock dyno or 7k shocks and a big testing budget! Obvious is moving everything to the trunk that you can and lighten the front of the car as much as possible. Never give up trying to increase front grip! And then add…
Diffs can make a huge difference as well (again the gains are a quicker turning car not a huge increase in mid-corner speed). The testing I have been lucky enough to do has shown that clutch type "one-ways" (no locking on decel) are the best. We have not yet tested the latest torsions however. Taller rear tires in the rear also trick the car into biasing more power to the back and put a little desirable rake into the car (not so center diff friendly so I wouldn't do a cross-country drive that way!). After it's all said and done you will probably end up with a bigger rear bar anyway BUT it won't need to be full stiff and you will have the ability to run a much less aggressive alignment which will give you a car that is a lot less spin prone (think slalom). To get back on topic your front bar on a fully modded car will be about half as stiff as stock...
There is no magic pill for good handling no single mod that makes it work. Its 20 different things tuned and tested to work together with the particular car/driver, those pesky laws of physics and the particular track
. We created a car that turns a lot quicker (but is just as stable in transitions) that have much better overall grip and oh yea, because it turns so efficiently it doesn’t sit at steady state for long (in relative terms) so we have minimized the effect of that lousy weight distribution and used to our advantage where possible. Time to fly!
The things to remember are that this is not a black and white issue and it won’t be cured with just anti-roll-bars. Just to focus on the Evo's glaring problem; it’s the weight distribution, at 60f/40r your mid-corner speed is going to suffer and understeer will always be a problem. That means the driver can use various tools (adjust driving technique) to minimize the problem BUT if the corner has any sustained (steady state) cornering the understeer is going to rear it's ugly head no matter how good the driver is (Mark!). This understeer can be described as the front tires at maximum lateral grip (slip angle) and the rear tires significantly below their max (properly driven). This is why it's slow at this point in the corner. Picture now a BMW M3 at the same corner and for the sake of this comparison it has the exact same tire size and type as the EVO (we know it doesn’t in real life). Except the BMW has 50/50 weight distribution. At the same sustained mid-corner phase as the EVO it is balanced with equal load on both "axles" (fr/r). Front ties at 100% REAR @ 100% = higher corner speeds due to the better balance and maximizing all tires.
So how do we fix the EVO? First realize it will never have the mid-corner speed of the BMW but don't worry it doesn’t have to be faster! We do want to optimize mid-corner speed by INCREASING front end grip but to go faster we also need to take advantage of the AWD system on the way out and the weight bias on the way in.
As we discussed above the more weight you have towards the rear (up to 50%) the higher your mid-corner speed will be but...but the more spin prone you car will be on entry! So we can be faster than the M3 from turn in to apex. We can brake later and carry more brake into the corner (yes the infamous "trail braking"). On the way out of the turn (described as when you start to unwind the wheel) we can (if you lined the car up properly with the trail brake in the turn-in the phase) progressively get into the power and put it down more efficiently than the M3. Our line (path through the corner) should minimize time spent at steady-state, which means a generally later apex that the M3. That's how a 271hp well driven EVO can beat a 333hp M3 as long as the course is not a skidpad or a bunch of connected steady state corners.
Now about mid-corner speeds. There are two ways to increase overall grip, one is easy and get you a small increase the other is much more complicated but the car is much faster after all that hard work and $$$. BTW we have talked about this all before so I apologize to all that are experiencing a sense of Deja' Vu right know
1. Easy way: reduce rear grip to balance (by putting on a bigger rear bar and/or increasing rear tire pressure reducing rear toe etc.). This will actually make your mid-corner speed slightly higher but where the speed increase comes from is how much more efficiently you can "rotate" the car on the brakes during corner entry and therefore open the wheel up sooner (therefore get on the gas sooner etc.). So yes you have slightly increase overall grip (witness the higher skidpad number over stock) but the car could be faster still…
2. Proper way: increase front grip to balance the car. Simple things; lower the front relative to the rear, widen front track (this can be overdone and increase understeer if geometry issues are not accounted for), increase spring rate (front) so we can soften the front bar and reduce lateral load transfer, increase rebound (front). More complicated things...measure bump-steer up front then fix issues and optimize alignment specs (through testing). Notice that it is all done at the front (there is nothing wrong with the back!). There is more but it requires a shock dyno or 7k shocks and a big testing budget! Obvious is moving everything to the trunk that you can and lighten the front of the car as much as possible. Never give up trying to increase front grip! And then add…
Diffs can make a huge difference as well (again the gains are a quicker turning car not a huge increase in mid-corner speed). The testing I have been lucky enough to do has shown that clutch type "one-ways" (no locking on decel) are the best. We have not yet tested the latest torsions however. Taller rear tires in the rear also trick the car into biasing more power to the back and put a little desirable rake into the car (not so center diff friendly so I wouldn't do a cross-country drive that way!). After it's all said and done you will probably end up with a bigger rear bar anyway BUT it won't need to be full stiff and you will have the ability to run a much less aggressive alignment which will give you a car that is a lot less spin prone (think slalom). To get back on topic your front bar on a fully modded car will be about half as stiff as stock...
There is no magic pill for good handling no single mod that makes it work. Its 20 different things tuned and tested to work together with the particular car/driver, those pesky laws of physics and the particular track
. We created a car that turns a lot quicker (but is just as stable in transitions) that have much better overall grip and oh yea, because it turns so efficiently it doesn’t sit at steady state for long (in relative terms) so we have minimized the effect of that lousy weight distribution and used to our advantage where possible. Time to fly!
Sep 28, 2011, 05:17 AM
#14
In all honesty to compete in SM and for that matter do well in pax, you will need (at minimum):
Good Coilovers
Hoosier A6 tires (preferably 285 30 18)
Decent alignment -3 degrees camber or more up front and -1.5 degrees in back or more.
Good Brake pads
And be a good driver
Plenty of BSP evos running similar times or better to SM evos. Stock turbo with E85 is a game changer and if I had it here, I wouldn't consider doing a turbo upgrade until you do what I mentioned above. I would only do the rear diff upgrade (1.5 way) after the above as well. You can be pretty competitive with the stock diff.
I honestly tried the I'll just go there to have fun, but it gets bored being beaten by lower classes due to the pax system. If you are serious, I'd do what I mentioned 1st. Drive a season before going any further. Seat time will be key.
Good Coilovers
Hoosier A6 tires (preferably 285 30 18)
Decent alignment -3 degrees camber or more up front and -1.5 degrees in back or more.
Good Brake pads
And be a good driver
Plenty of BSP evos running similar times or better to SM evos. Stock turbo with E85 is a game changer and if I had it here, I wouldn't consider doing a turbo upgrade until you do what I mentioned above. I would only do the rear diff upgrade (1.5 way) after the above as well. You can be pretty competitive with the stock diff.
I honestly tried the I'll just go there to have fun, but it gets bored being beaten by lower classes due to the pax system. If you are serious, I'd do what I mentioned 1st. Drive a season before going any further. Seat time will be key.
