I am not sure to be honest. The only Ca. track I had been on before this year was Laguna Seca. I don't know which ones have the proper facilities. Shiv is investigating the possibilities we are trying to do a couple of days around the EVO shootout days.

 

Look for the tracks WERA and the long-track karts go to. Or where SCCA does schools, they usually try to go to safer tracks.

 

Scott,
I need some more clarification. During braking the weight transfer will add aditional grip to the front tires, but won't it add a force pushing forward (tangent to your line/linear to your cars current attitude)? So isn't the extra grip just neglected by the new force?

I also don't understand the "With more weight in the rear the rear wants to go out" statement. Is that saying for some reason when more weight is "pressing down on the rear tires it wants to lose traction but with more weight on the front you gain traction? This confuses me with the argument amount powering through the turn. That comment is similar to one earlier, in response to Robi, about powering through the corner. You said something to the likes of losing grip in the rear. How is that possible when powering through a corner?

I'm just trying to piece this technique together.

 

I gave Scott a generous 13 seconds to respond...where is that guy


just the opposite, releasing the brake or adding gas will cause the car to want to go straight. You have to be able to picture the car reacting when you brake. The car will rotate around its center of gravity which is about where the base of your shifter sits. As you brake the car will rotate around it pushing down on the front tires as it simultaneously lifts the rear removing the exact same amount of grip (load) from the rear as it adds to the front. Now imagine how this affects the tires. your front (steering) tires get extra vertical load they are pointing into the corner this extra load improves their ability to go where they are headed especially when you factor in that the rear tires pointing straight towards the outside of the corner have their precious grip levels reduced. Add it all up and the harder you trail brake (until the point of lock-up) the MORE the car will follow intended path (where the front tires are being pointed by the driver). Only if you lock the front wheels will the car go straight.


First we need to understand the difference between driver induced vertical load changes and static vehicle weight distribution. Scott is referring to centripetal force pulling on the car LATERALLY (from the side) this is why the cars weight distribution effects the basic handling balance of the car. First imagine a lead ball on a string spinning above your head with a scale attached to the string. as you spin the lead ball at x-feet per second it registers 10 lbs on the scale, ok? Now we put a lead ball that is slightly bigger on the string and you spin it at the exact same speed and look at the scale, it's going to register higher right?.

Now imagine the heavier weight represents EVO's front axle and the smaller ball actually represents to the rear axle. The EVO is driving in a circle (skid pad) driving faster and faster when the equal sized tires (front and rear) approach their grip limits the fronts slide first (causing "understeer"). Why because more "weight" was tugging on those front tires than the rear so the front slide first every time.

Now vertical load, the more vertical load you (the driver) put on the tires the more grip they have so it has the opposite effect as weight distribution and in fact you use this ability to load or unload one end or the other to counter inherent problems with the static weight distribution of the car. Using Trail braking to add the extra grip in the front so the car does not want to understeer anymore. Hope it helps

 

Gotcha. Thanks.

So now how do I stop that understeer when exiting? This thing pushes everytime I power out of a turn. Ughhh. Well not everytime, but on one particular off camber turn.

 

That ones easy... front LSD diff!

The driving fix would be two-fold first be slower on the throttle and use a later than usual apex on that corner, knowing that there is less grip post apex means you need to be going straighter when you get to the off camber bit. It is the same as a wet spot in the turn or snow/ice/gravel/sand. If the surface has differing grip levels, turn where the grip is, go as straight as possible where the grip isn't

 

[QUOTE=chronohunter]That ones easy... front LSD diff!

Front LSD enhances the AWD systems natural desire to push (don't the subies cry that our open front dif cars turn better than their LSD STI's) as the front axle locks up and starts spinning both tires at the same rate. I know just trail brake on exit to get the front wheels to grip more ;-). PS don't believe me? get in a 4wd offroad vehicle with a locking front and try some tight turns in low traction conditions..and yes I was doing this in my 68 bronco before you were probably born. (Oh thats right I remember you tried this in one lap too. didn't you paul???? seemed you had MAJOR understeering push DUE to your Front LSD locking up under power (just like the engineers designed it to). Paul don't worry about a rebuttal keep gushing for the uninitiated this is robi signing off "timeseeker" (I'll continue to lose the time I encounter) cause with your last 100% wrong post I realise the lunitics have started running the school for the insane...BTW when you start posting times as fast as mine on the tracks out here...(I mean at Thunderhill you had a colder day, wider tires, a more expensive suspension, 150 more Horses and a "world class driver" How can a 47 year old NEVER BEEN PAID TO TEACH DRIVING OR DRIVE ANYTHING be .8 seconds faster? anyone who want's the links just pm me) or sit in the car to watch me drive, keep your "helpful" assumptions on how I corner, what line or # corner type it is, and what I need to do to improve to "get to your level of world classyness" to yourself. Unsolicited assistance cheapens you and just pisses most people off. (if and when I decide I need help. As often happens. I'll go to the people who have earned my respect. BTW your posts in this thread arn't helping your chances much), It makes you seem almost as pompas as your evo mentor and if you can't see from CO, the people who are the closest to the boy are the ones who want the least to do with him..( banned from both the two biggest evo markets websites, Norcalevo.net (where his shop is) and Socalevo.net They won't even take his money and let him advertise...damn you guys must be doing something right ;-). Oh I know "it's personal". Well, Once it's a fluke, twice it's a pattern, thrice and your out of my(and many peoples) invite book. Ever wonder why the only press is through C&D?....and none of the import mags waste any time..like I said he's been in this market longer than he's had a shop. I'll let you draw the conclusions...
PS see you at the Time Attacks...and you better bring a better hand than you've been playing so far.

 

Robi-- u r way too bent out of shape. And a bit biased about what you consider to be fact

 

Robi, easy killer, Paul has not been bashing you, why the animosity toward him??? Seriously, no need to personally attack Paul because you have a different opinion about a driving technique/setup thing.

The open front diff on the Evo's improves turn-in, but for powering off a corner the STi's LSD front is great, well the '04 Hypoid maybe isn't great, but it's good, and the '05 helical IS GREAT for coming off a corner without exessive push. I believe the Time Attack article in SCC talked all about how the stock Evo RS with the LSD front handled SO much better in the tight corners than many of the modified EVOs. IIRC it was the RRE Evo that also did so well there, even without the front LSD, but this kind of brings in the point we've been making the whole time; stay with me here:

Going to a LSD front increased the front grip enough that the RS hooked that corner without understeer. IIRC the RRE car was so easy to get to rotate (loose) that it also rotated the corner without understeer. Two appraoches, both faster than others, but one is increasing front grip, and one is decreasing rear, which do you think is the faster method.....

Anyway, the open front diffs make the steering lighter, the car feels more "flickable" but they are not better for traction coming off a corner. If you can have 4 tires pulling and cornering, why have only 3, less rubber = less grip. Granted balance is more important than the last few mm of rubber, but if you can get that balance anyway, more rubber is better.

There is a reason that Mitsi is going to the LSD front on its "better" Evo's.

The stock STi's are, like almost all car sold here in the US, setup for predominantly safe understeer. With a little work, even really just an alignment to a 0.6+ more camber in the front (1.8 front 1.2 rear, or 2.0 front 1.3 or 1.4 rear depending on sway bars) they get much better. Combine even just springs that lower the front to even with the rear and good alignment and you've got a machine that runs REALLY well, minimal push off a corner. Throw bars at that setup, or a coil-over setup and you've got a dominant machine, partly BECAUSE of the front diff....

Anyway, Paul only jumped in here as strongly as he did because it was being said to NEVER trail-brake an Evo, didn't even you say a stock EVO (what many reading this thread likely have) NEEDS to be trail-braked?

Plus, do you really make sure you are ALL the way OFF the brakes before you turn the wheel AT ALL??? As in, you slow down in a straight line, then get back on the gas, THEN turn in....??? Even in the lower speed corners???

 

Well, I think this thread is done, nearly ever possible technical explanation has been given and there is quite a bit of good information (although painfully boring to read ). So, for everyone like myself, ie. the novices, get out there and learn as many methods to driving as possible, get comfortable trail-braking and not using the brakes. That way you can decide for yourself which method is faster for you, and more importantly, which method you prefer. And if you find yourself a competent suspension tuner he'll be able to make the most out of your prefered driving method. John sends a full questionaire about your driving experience, planed usage and your vehicle to try to get it right.

And as for Robi getting upset, well it really is understandable. He is very competitive, like myself, and when you have to explain yourself like he doesen't know what he's talking about because he doesen't use the same driving techniques that "world class" drivers use, well, then he gets upset. Not because you are a great driver and a engineer, but because his car is faster than yours. He doesen't want to be told how fast the physics book says he should be, and as Rob from RRE pointed out, the winner of the internet forum physics debate might be the slowest driver out there. It's sort of like why all the "dsm" tuners dislike Shiv's antics. Because he was always the one to tell us how Dyno's lie (and cruxified Al for using 100 Octane race gas, now all he posts are C16 dyno charts), and then he comes clamoring when he nexts 550whp with a GT35R. (On a dyno that claimed the air temperature was 139 degrees, maybe you should come clean?) Well, he should have made 550whp, and no one, or anyone I talk to, finds that impressive. AMS made 667 with their larger GT35R (690 uncorrected) and 600 with their fast spooling GT35R. And then Shiv won't take his 550whp Evo to the dragstrip to see what that equates to in the real world. So are we competing in dyno races/forum races or on the track?

 

I still don't understand how that equates to personal attacks on Paul.....

 

[QUOTE=robi]umm ok. We shall see you there. I think your angry old guy thing really works for you on the forums, it's very friendly.

So I was within .8 seconds of your best lap ever with limited laps (the clutch snap ring went early in the day ) on a track I'd never seen before with the bottoming bouncing Cusco suspension on an undeveloped car.

Why do you choose to attack me when I have never done so to you? You could be more productive to all by answering my questions you keep dodging. Remember all those comments you keep throwing in my face (like "world class driver") were never said by me. They were said by people coming to my defence after one of your many attacks (and I don't have control of what people choose to say about me good or bad). Play nice please

Why is adding grip with aero ok while adding grip with trail braking is not ok, only the trail braking will overheat the tires?

 

So, let's end this friendly internet jousting on the track. Paul you're going to bring the shop car out to the November 28th Willow Springs Evolution track day, there is going to be a competition class with some very fast evolutions?

 

Good first paragraph - why the neeed for the 2nd, I don't know?

 

The RRE car had in that SCC EVO competition and still has at this moment the helical (Torsen type) EVO V stock front differential.

One drive around the block with the EVO 5 differential and I could tell it was understeering huge compared to the nice neutral it was a few hours before installing the diff. Even with out hard driving.

Mike W