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2014 BStreet Autocross Roll Call!

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Old Apr 9, 2014, 08:20 AM
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Thanks for the input everyone.

Originally Posted by MrAWD
From the above it sounds like you are thinking of getting Rear sway bar to help you rotate...right? If that is wrong, disregard the rest!

I know that discussions between FSB and RSB are close to the religious debates, but I have to point few things right now. In the above text, you clearly describing that you front end is suffering tremendously due to excessive rolling of that end, but instead of thinking of fixing (or at least aiding that) you are trying to leave it intact and improve the other end instead. Bu going with stiffer bar, you are pretty much making that end to stick less than before (this is the most simple wording I can use here). So, the overall result will be less stick on the rear with hope to get faster!?

The above logic makes sense on car which has allowance to modify both shocks and springs and were you have done everything you could possible done to increase the grip on the other end. For the stock/street car that is not the case. You have lots of limitations and you have to correct the logic a bit.

So, the get back to your original issue! If you could improve the grip in the front, that would make your car much faster than it is right now or it will be if you take some of the grip from the rear to make it more loose! So, stiffer front sway bar would decrease amount of roll you get while cornering and keep geometry of the front end in a better shape. That would give you more grip and a bit less abuse on those tires. Once you increase front grip, car will become looser as the side effect and bring you back to the fun car you want to drive in the first place!

Fedja
ps. and yes, I would recommend Whiteline for the front!
I agree that the optimal situation would be to improve grip at the front and not reduce grip at the rear, but I don't believe the problem can be solved with a front bar. The front bar will do a few negative things:
1. Lift the inside wheel. With a helical limited slip in the front, that's a bad thing. The Evo's advantage in BS is putting power down earlier. If I'm spinning the inside front tire, that reduces that advantage. It also reduces front end grip.
2. Reduces compliance in the front - it will likely induce understeer, and further exacerbates the fact that the front has less relative grip than the rear, primarily due to weight on each corner, which cannot be changed with a bar.

So I went with the Whiteline Rear Bar, with the thought that the balance will make the car transition faster so that I can get back on the gas sooner.

Fedja, you're in New England, right? You should come down to the NJ Championship Tour next month, we're at 9 registered for BS, and one of the drivers that's currently registered will likely be there in an Evo instead of what he's currently registered in.
Old Apr 9, 2014, 11:15 AM
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Originally Posted by ChrisV
I agree that the optimal situation would be to improve grip at the front and not reduce grip at the rear, but I don't believe the problem can be solved with a front bar.
If you believe/think it is impossible, it is possible you are not thinking...
Originally Posted by ChrisV
The front bar will do a few negative things:
1. Lift the inside wheel. With a helical limited slip in the front, that's a bad thing. The Evo's advantage in BS is putting power down earlier. If I'm spinning the inside front tire, that reduces that advantage. It also reduces front end grip.
I have installed front bar last year and have yet to experience front inside wheel spin. That said, if I want to do it I could make it to spin at will - the hack, it even spins in the straight line acceleration if you hit it that way.

What I am trying to say here things are not that simple. Yes, if you smash the throttle all the way at the apex of the turn chances are that you will get some wheel spin on inside (stock or after-market bar in the front). But, at the same time, more smoother application of the throttle will most likely make it for better times and much less of the tire abuse. Now, I don't know you ChrisV and I have never seen you running, so this is nothing aimed directly to you, but general audience instead. If you do experience lots of tire wear in the front and car being too tight (or even lot of push), it is possibly that you are just clearly overdriving the front tires. One would say that FSB would do just that, but my car is still looser than most of the other ones around and if anything is going to give up, it will be still the rear end. And that is with the biggest front bar I could find! On full stiff!! Had to run rear tire pressure around 7 psi lower than front just to keep it right and it was still hard at times.
Originally Posted by ChrisV
2. Reduces compliance in the front - it will likely induce understeer, and further exacerbates the fact that the front has less relative grip than the rear, primarily due to weight on each corner, which cannot be changed with a bar.

So I went with the Whiteline Rear Bar, with the thought that the balance will make the car transition faster so that I can get back on the gas sooner.
If you had lots of stiffness in the front than above would make sense. But, EVO X is anything but stiff in the front. Stiff bar helped a bit, but car is still rolling and pitching a lot more than it is healthy for competitive times. Pretty much, good shocks are must in order to keep those movements under control.
Originally Posted by ChrisV
Fedja, you're in New England, right? You should come down to the NJ Championship Tour next month, we're at 9 registered for BS, and one of the drivers that's currently registered will likely be there in an Evo instead of what he's currently registered in.
Well, back in days that was piece of cake. Now with kids, not that much any more. Still, if my car would be better prepared (read: eventually when I get shocks for the car) and there is no sense to get there to every event around here. Next year perhaps...

There should be National Tour at Devens coming up, so we can get that one together!

Fedja

Last edited by MrAWD; Nov 13, 2014 at 06:52 PM.
Old Apr 9, 2014, 11:22 AM
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I have an EVO X 25mm Perrin RSB and Racing line endlinks I would sell for cheap (BRAND NEW) if anyone wants them. I went with the Perrin as it is the smallest available, I don't think you need a giant RSB with the evo's already tendency to off throttle oversteer and trail braking, you also want to minimize dog legging which you see when you get giant RSB's.

Anyways, I would highly recommend if you plan on running the car in B street or STU to upgrade. Plans changed for me and I am focusing more on Road Racing for the evo, and another direction for autox. I decided to go with some mega stiff spring rates and using the stock bars so no need for this guy. Looks purrrrdy in red too!
Old Apr 9, 2014, 11:34 AM
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In regards to the FSB talk. Biggest real world race advantage you will see is in slaloms, car feels much more precise, less front roll, great transitional benefits and helps maintain what little camber you have up front. Downsides....Sweepers, you die in sweepers...lol. Not quite that dramatic but the car won't want to steady state or decreasing radius sweep, not like it would with a stock FSB. Of course you can do a few things to counter this, less rear camber, a little toe out both front and rear. Basically getting the rear to move around a bit more. It's hard to find that balance though as it feels great and wags through the slaloms, but sucks through the sweepers so you loosen it up and it becomes REAL loose in the slaloms but way better in sweepers. At this point you lost the benefit of the FSB.

Point being is that if you like a car that is EASY to drive the FSB is great, makes it feel much better in most elements, yes sweepers blow, just be patient and don't over drive them, you will push if you get on the throttle too early.

If you want a car that will steer with the rear and IMO be faster overall go the RSB route.

Like the previous poster said it's not black and white, and I really prefer to test my own setups instead of reading internet banter, I can tell you that just because one setup works for someone it may not work for you, hell it may be way off but they just "think" it's fast.
Old Apr 9, 2014, 12:45 PM
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^^ Sounds like you need some shock tuning to get that control back in transitions and keep the car somewhat loose for steady state.

I agree with Fedja on the bigger FSB. You aren't nearly stiff enough overall to lift a front tire in BS. What you lose in grip from extra weight transfer should be more than made up by the decrease in camber loss. Loosening the rear is pretty easy with some tire pressure changes for steady state or shocks in transitions. I prefer to keep my rear camber more ideal and not use that for adjusting balance. Seems to keep things less snappy that way, but that might just be my butt talking.
Old Apr 9, 2014, 03:24 PM
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Originally Posted by Dallas J
^^ Sounds like you need some shock tuning to get that control back in transitions and keep the car somewhat loose for steady state.
Possibly, however keep in mind that limited shock tuning is available on the evo x platform. You can send your shocks out for re-valve but if they don't get it "Right" that's that. You don't have knobs to turn to increase or decrease rebound/compression and no aftermarket shock that uses the stock springs exists unless you shell out the cash for something custom.
Old Apr 9, 2014, 04:21 PM
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Ahh, gotcha. I guess I can see that the aftermarket would assume most go straight to coilovers if the car is raced.

Time for something Cu$tom!
Old Apr 9, 2014, 09:43 PM
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Just a quibble, but an Evo (esp. an X) has one of the strongest chassis (in terms of torsional stiffness) of any production sedan ever made. We don't suffer from "front [body] roll"; we only suffer from body roll.
Old Apr 11, 2014, 03:11 PM
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If anyone wants to max out the track width or gain tire to strut clearance, we have some ultra light 6.5mm thick wheel spacers that meet the SCCA stock rules.

Rick
Attached Thumbnails 2014 BStreet Autocross Roll Call!-spacer.gif  

Last edited by SS RX7 r2; Apr 14, 2014 at 08:40 AM.
Old Apr 19, 2014, 08:05 PM
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Finally, first event in the books! With new tires which were not Hoosiers for a change!

So, after having a chance to try my new tires in the size everyone was saying it will be bad (275/35/18 on stock 8.5" rim) I could finally write my own impressions of those. Started with 40 psi all around. Fronts got hotter than the rears and climbed to 42s, while I kept rears at 40. Wear was still up to the arrows on the side and it didn't seem to roll over more than it should at those pressures. As a mater of fact, I might go even lower on both ends. I did ended up with somewhat strange wear (I will post the picture later), which is hard to explain. But, more on that one later.

How did it feel? Was it squishy as I was told it will be? Shortest answer is not really! As a mater of fact, I am not sure what people were referring to. Tires felt just fine! On a stiffer suspensioned car it might be more noticeable, but on EVO X with stock suspension, not at all. Actually, feel was pretty close to the Hoosiers, but with less overall grip. That might be something that was actually helping heavy car as EVO. Due to less overall grip, car was not rolling as much as it used to do with Hoosiers, so it was a bit easier to control it.

As a mater of fact, this was very first time that car was just right! Not too loose and not tight at all - just the way the doctor ordered! The best part was that guy who was with me last year, in nicely prepared CR (those got moved up to the AS), and was beating me 3-4 seconds at least every single time, ended up just over a tent of a second faster. He was using ZIIs.

I am beginning to believe that this street thing might be actually helpful for us EVO guys in there! One thing that still unbalances the car a lot is brakes. That part didn't change much (maybe slightly due to less grip now, but not much) and nose still dives a lot when you smash on the pedal. My co-driver was having most of the issues with brakes in that regard. I do believe that once more rebound is turned up on all four and perhaps touch of compression as well to the dumpers, this will be less of an issue, since body will not move as much and as quickly any more. But, I am not there yet, so that will be left for some other discussion.

More one that strange wear. It was obvious that outside edges got beating. But, there are two curvy strips outside of the middle bar on both sides and only the inside one got some wear. Outside one (near the outside edge) got no wear whatsoever. At this time I have no explanation for why this happened. Again, as soon as I get picture ready, I will post it below. The only thing that I could think of is that I was running too little pressure and those two spots were the ones making it work. Next time I will measure temperatures on the thread itself so I will have better idea what is going on.

At the end, I am very glad that I went with 275s. They seem to be pretty good at the moment.

Fedja
Old Apr 21, 2014, 09:11 PM
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Originally Posted by MrAWD
Finally, first event in the books! With new tires which were not Hoosiers for a change!

So, after having a chance to try my new tires in the size everyone was saying it will be bad (275/35/18 on stock 8.5" rim) I could finally write my own impressions of those. Started with 40 psi all around. Fronts got hotter than the rears and climbed to 42s, while I kept rears at 40. Wear was still up to the arrows on the side and it didn't seem to roll over more than it should at those pressures. As a mater of fact, I might go even lower on both ends. I did ended up with somewhat strange wear (I will post the picture later), which is hard to explain. But, more on that one later.

How did it feel? Was it squishy as I was told it will be? Shortest answer is not really! As a mater of fact, I am not sure what people were referring to. Tires felt just fine! On a stiffer suspensioned car it might be more noticeable, but on EVO X with stock suspension, not at all. Actually, feel was pretty close to the Hoosiers, but with less overall grip. That might be something that was actually helping heavy car as EVO. Due to less overall grip, car was not rolling as much as it used to do with Hoosiers, so it was a bit easier to control it.

As a mater of fact, this was very first time that car was just right! Not too loose and not tight at all - just the way the doctor ordered! The best part was that guy who was with me last year, in nicely prepared CR (those got moved up to the AS), and was beating me 3-4 seconds at least every single time, ended up just over a tent of a second faster. He was using ZIIs.

I am beginning to believe that this street thing might be actually helpful for us EVO guys in there! One thing that still unbalances the car a lot is brakes. That part didn't change much (maybe slightly due to less grip now, but not much) and nose still dives a lot when you smash on the pedal. My co-driver was having most of the issues with brakes in that regard. I do believe that once more rebound is turned up on all four and perhaps touch of compression as well to the dumpers, this will be less of an issue, since body will not move as much and as quickly any more. But, I am not there yet, so that will be left for some other discussion.

More one that strange wear. It was obvious that outside edges got beating. But, there are two curvy strips outside of the middle bar on both sides and only the inside one got some wear. Outside one (near the outside edge) got no wear whatsoever. At this time I have no explanation for why this happened. Again, as soon as I get picture ready, I will post it below. The only thing that I could think of is that I was running too little pressure and those two spots were the ones making it work. Next time I will measure temperatures on the thread itself so I will have better idea what is going on.

At the end, I am very glad that I went with 275s. They seem to be pretty good at the moment.

Fedja
Good to hear they are working and working well. Any chance you have another evo x running in the club you could swap wheels with at a test and tune to get some hard data? Do you plan on attending any national events?
Old Apr 21, 2014, 09:21 PM
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Good to hear that the 275s are working out for you. You might want to post that tire wear picture in this thread too, rather than the separate thread.

How much camber could you get out of the front end? That probably explains a lot of what you're seeing.
Old Apr 22, 2014, 05:46 AM
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Fedja,

Finishing only 0.171 seconds behind an A-Street driver/car that has finished mid-pack at nationals (in B-stock) in 2012 and 2013 is very impressive. Good job. I've long felt the switch to street tires would benefit the AWD cars. And it looks that A-Street S2000 CR had a "tire warmer" co-driver for him - you didn't.

As for over-tire and FSB versus RSB decisions, the car has to be adjusted for the individual driver. Whenever I've done co-driving, I experience more understeer than my co-driver (who normally complained of oversteer). So I no longer co-drive with anyone. I adjust the car for me and no one else.

-- joe
Old Apr 22, 2014, 07:24 AM
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Originally Posted by Construct
Good to hear that the 275s are working out for you. You might want to post that tire wear picture in this thread too, rather than the separate thread.

How much camber could you get out of the front end? That probably explains a lot of what you're seeing.
I have created a separate thread for that tire wear, so no need to stick here as well!

As of the camber numbers, latest alignment showed 2.1 on the passenger front vs. 2.0 for the driver. That seem to be it.

In the rear, last year I was running 1.0 on both side with 0.08 degrees of toe out on each side (NTB guys didn't listen to me when I asked for 0 toe in the rear, because it was out of the factory specs). That was changed to 1.5 degree and finally 0 toe right before the event. From the wear markers on the tires in the rear, they were barely getting to the top of the arrows , so it allowed me to drop the pressure from 40 to 39 without any issues. I have a feeling that it could go down another psi or so if needed, but at this time car was handling pretty nice, so I will keep it there for a while longer.

Fedja
Old Apr 22, 2014, 07:28 AM
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Originally Posted by gumby4mayor
Good to hear they are working and working well. Any chance you have another evo x running in the club you could swap wheels with at a test and tune to get some hard data? Do you plan on attending any national events?
I don't think there are any other EVO X around. There is a fast STU EVO 9 there, but he has bigger wheels and they are probably 17s a s well.

So, as of now, I can compare my time with one fast STU EVOs (Brian is his name I think) and luckily Justin is in ASP with his monster and as soon as it start to work the way it should, that car will give me some nice comparison as well.

As of National events, Match Tour is coming to Devens in a short while so I am planning to be there for that. Aside of it, I think that is it until I manage to get proper dampers on the car instead of the stock ones.

Fedja

Last edited by MrAWD; Nov 13, 2014 at 06:58 PM.


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