The STX thread!
06-15-2009, 09:58 AM
#126
Registered
Join Date: Feb 2006
Location: Oreland, PA
Posts: 271
Likes: 0
Received 0 Likes
on
0 Posts
I'm getting some odd 'bouncing' in the rear of the car, under throttle around tight corners. It could be the surface we were running on (old concrete with lots of seams), but I think I've seen it on other surfaces. I was going to stiffen the rebound and compression damping, but I talked to a friend of mine first. His recommendation was to look at the swaybar and make sure it isn't binding. If I have the time tonight, I'm going to jack up the rear and try to see that myself. I can just pull the springs off the coilovers and compress one side. It's possible that lowering the car so much is causing the swaybar to bind, as he suggests. It's certainly not being twisted as much as it would be in a stock set-up, but it could be hitting something since the car is lowered.
06-15-2009, 10:11 AM
#127
Registered
Before I go replacing parts or changing settings, I'm going to see if anything's binding. I'm hesitant to change anything that would upset the car in faster sections. I'm really happy with how it feels at higher speeds right now. Stiffer damping (my coilovers adjust compression and rebound together) might make the car a little less predictable around fast bends.
Last edited by Mr. Pockets; 06-15-2009 at 10:14 AM.
06-15-2009, 10:37 AM
#128
悪魔のR
iTrader: (12)
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Likes: 0
Received 0 Likes
on
0 Posts
Totally understandable. Yeah check for binding, but also, check your bushings and see how the grease is holding up. Never know, may need some regreasing..I had that happen before.
06-15-2009, 01:15 PM
#129
I had the KWs installed and drove up to Packwood, and the car worked great! I was really impressed with how well it handled right out of the box. I let a friend drive it who is normally pretty critical of handling nuance and when he got back he said he was having so much fun he forgot to think about how it handled.
It was a little softer than I expected on turn-in. Not bad, but not what I expected. I had set the rears to 50% damping on rebound. I learned too late from Brian Goodwin that I should have gone stiffer, and I know now that he’s right. I’ll drop the rears and add a turn this week. I didn’t play at all with compression.
It pushed a little mid-corner, but not too bad. I lowered the front one turn Sat night, and that helped the mid-corner push. I’m not saying it’s optimized, but it felt better for sure.
Corner exit felt very good – I could put the power down with slight but very controllable oversteer.
Steady state and transition grip was noticeably higher than when I had the stock suspension. After the first few turns in the first run I found myself thinking I need to drive it like it had R compounds again. No, I really don’t think it has that much grip, but it is stickier than the last event (which was on the R1-Rs but the stock suspension) for sure.
Slaloms were amazing. I just drove through them. No drama. In fact, I’m not certain if I’m driving the car fast enough yet in the slaloms.
I took tire temps once and saw a 10 degree spread inside to outside (102 to 112) with the center being 1 degree warmer than the outside edge. This was on one of the earlier runs so I suspect the spread may get worse. Tire pressure (17” R1-Rs) were 34/32. I’ll check temps more thoroughly at the NW region event this weekend.
I was the fastest STX car both days, but I entered PAX so I can’t technically say I won STX. I paxed in 5th place both days, out of 100-120 drivers. The top four were either national champs (Jerry Jenkins, James Paulson) or top national drivers (Jim Daniels, Ryan Otis). I’m about 1.8 to 2 seconds off Jerry’s time, raw, which is the best metric I have for Oregon region events since there are no national-prep level STX cars in Oregon yet, and the ES index is virtually identical with the STX index.
The street ride quality of the KWs is surprisingly good. I’m sure that will suffer some when I dial up the damping, but these units are fantastic. I’m sure there is something better out there, but for under $2k they are really hard to argue with.
Best of all – no mechanicals! The guys at Adrenaline Racing did great installation work.
Finally, despite my recent sniping, I’d like to publicly thank Jason and Mark for helping me in my coilover selection process. They both alerted me to the Eibach/Mazdaspeed issues (there’s that informed issue Mark likes to talk about), and Mark prompted me to reconsider KW, and I’m glad I did. Thanks guys!
George
It was a little softer than I expected on turn-in. Not bad, but not what I expected. I had set the rears to 50% damping on rebound. I learned too late from Brian Goodwin that I should have gone stiffer, and I know now that he’s right. I’ll drop the rears and add a turn this week. I didn’t play at all with compression.
It pushed a little mid-corner, but not too bad. I lowered the front one turn Sat night, and that helped the mid-corner push. I’m not saying it’s optimized, but it felt better for sure.
Corner exit felt very good – I could put the power down with slight but very controllable oversteer.
Steady state and transition grip was noticeably higher than when I had the stock suspension. After the first few turns in the first run I found myself thinking I need to drive it like it had R compounds again. No, I really don’t think it has that much grip, but it is stickier than the last event (which was on the R1-Rs but the stock suspension) for sure.
Slaloms were amazing. I just drove through them. No drama. In fact, I’m not certain if I’m driving the car fast enough yet in the slaloms.
I took tire temps once and saw a 10 degree spread inside to outside (102 to 112) with the center being 1 degree warmer than the outside edge. This was on one of the earlier runs so I suspect the spread may get worse. Tire pressure (17” R1-Rs) were 34/32. I’ll check temps more thoroughly at the NW region event this weekend.
I was the fastest STX car both days, but I entered PAX so I can’t technically say I won STX. I paxed in 5th place both days, out of 100-120 drivers. The top four were either national champs (Jerry Jenkins, James Paulson) or top national drivers (Jim Daniels, Ryan Otis). I’m about 1.8 to 2 seconds off Jerry’s time, raw, which is the best metric I have for Oregon region events since there are no national-prep level STX cars in Oregon yet, and the ES index is virtually identical with the STX index.
The street ride quality of the KWs is surprisingly good. I’m sure that will suffer some when I dial up the damping, but these units are fantastic. I’m sure there is something better out there, but for under $2k they are really hard to argue with.
Best of all – no mechanicals! The guys at Adrenaline Racing did great installation work.
Finally, despite my recent sniping, I’d like to publicly thank Jason and Mark for helping me in my coilover selection process. They both alerted me to the Eibach/Mazdaspeed issues (there’s that informed issue Mark likes to talk about), and Mark prompted me to reconsider KW, and I’m glad I did. Thanks guys!
George
06-15-2009, 02:59 PM
#130
Power!!
I noticed in the rules we can move our cat. converter 6" south. Some of the Koni Challenge guys say there is benefit to having longer length exhaust header runners. Anyone looked a custom exhaust with relocated cat and longer exhaust runners?
06-15-2009, 06:37 PM
#135
Registered
Join Date: Jan 2003
Location: San Diego, CA
Posts: 402
Likes: 0
Received 0 Likes
on
0 Posts
P.S. Feel free to let me know offline if it's a secret.
06-18-2009, 11:43 PM
#138
I would suggest using the bars to address the mid-corner handling. Shocks mainly address dynamic handling entering & exiting. Despite how well the grip feels, you're not on R tires and compliance is a good thing.
Get the mid-turn right with the bars, then set the in/out balance with the shocks.
Get the mid-turn right with the bars, then set the in/out balance with the shocks.
Thanks - I do agree with your methodology. However, when I said that I lowered the front, I meant that I literally lowered the front suspension by moving the front spring perches down one revolution. The logic (right or wrong) is that by lowering the front roll center I am reducing weight transer across the front and thus increasing grip on that axle.
Of course, I realize that lots of thing change when you change ride height - alignment and bump stop engagement among them. So you never really know until you try (I had a Miata once that increased oversteer when I lowered the rear, which I attributed to bump stop issues). However in this case, it did seem to improve front grip a bit. Not sure what you think of this aproach (please do tell) but I learned about it at a handling seminar, and the equations in Race Car Vehicle Dymanics seem to back it up.
Anyway, I dropped the rears tonight and increased the rear rebound to 1/2 turn back from full stiff. Left compression alone. Tried to get my Tokico cables to work with the KWs but didn't quite get it right so I put it back together without the cables. I'll get it eventually - what can I say, I like my *****.
Also moved the front & rear bars from full soft to full stiff. I know, it's better to change thing one at a time, but I only have so many events. If it still pushes more than I like I'll back the front bar off and see how it gets on.
Sat is a pro against Ron & Karl. I think I'll just concede this one, and treat it as a test & tune event (and be nice to the tires & drivetrain). Sun is a regular event and should be interesting.
06-20-2009, 03:35 PM
#139
Registered
The ends of the rear sway bar are level with, if not slightly above, the sway bar brackets. I suspect that's what is causing my bouncing.
Is there such a thing as a shorter endlink?
I imagine that the real solution is just to raise the rear of the car about a half an inch. That's what I lowered it by, compared to last season, and it didn't bounce like this last year. Granted, I have way more grip than I did last year...
06-22-2009, 09:53 AM
#140
Yes, there are several shorter endlinks available. Evo-R, is one, there is another Team has reccomended. I went ahead and bought the Evo-Rs, even though various reports state that the stockers work OK even when lowered. I think you are the first person that has reported otherwise?
You run Stance, right? When you lowered the rear did you shorten the shock body or just lower the perch?
By the way, I did a quick test this weekend and my KWs are definately in the bump stops. Doesn't feel like it, at least compared to stock (no bouncing, ver controllable on the limit), but the bump rubbers get pushed all the way to the top of the shock shaft, at least on the fronts. Of course, Packwood has some nasty bumps, so I don't know if it's the mid-corner bumps, or just the corners.
You run Stance, right? When you lowered the rear did you shorten the shock body or just lower the perch?
By the way, I did a quick test this weekend and my KWs are definately in the bump stops. Doesn't feel like it, at least compared to stock (no bouncing, ver controllable on the limit), but the bump rubbers get pushed all the way to the top of the shock shaft, at least on the fronts. Of course, Packwood has some nasty bumps, so I don't know if it's the mid-corner bumps, or just the corners.
06-22-2009, 11:12 AM
#141
Registered
Yesterday I raised the rear of the car by about a half an inch. I'll get it aligned this week and see what happens this weekend.
I was trying to find adjustable end links for the car, but didn't see any listed specifically for the rear. Agency Power makes an adjustable for the front, but I don't know whether it works on the rear bar.
I think maybe, when a rear corner compresses in a corner, and then is pressed on even harder under acceleration, the bar end is being pushed up too high. Instead of the bar being twisted, the end is just being pulled up on. If I'm right, that's raising the bar's rate significantly and causing my bouncing.
Last edited by Mr. Pockets; 06-22-2009 at 11:16 AM.
06-22-2009, 11:42 AM
#142
There is a limit to the rotational range of motion of the end-links, and if you've reached that limit, then you are correct - you are getting binding and would likely be bad.
The Evo-R endlinks are specific front & rear, and work fine(for now) on my setup.
Good luck with the new setup. It is possible to go too low.
The Evo-R endlinks are specific front & rear, and work fine(for now) on my setup.
Good luck with the new setup. It is possible to go too low.
06-22-2009, 05:14 PM
#143
Any high flow catalytic converter(s) are allowed, but must attach
within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the single
replacement converter may be located no further downstream
than 6" along the piping flow path from the original exit of the
final OE converter.
One could interpret this as meaning that the inlet of the aftermarket cat can be 6" downstream of the outlet of the OEM cat, even if the car (as in our car) has only a single OEM cat.within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the single
replacement converter may be located no further downstream
than 6" along the piping flow path from the original exit of the
final OE converter.
But, I'm new to this rule interpretation business. Anyone care to comment?
06-22-2009, 05:48 PM
#144
What's interesting is that if you read the rules carefully:
But, I'm new to this rule interpretation business. Anyone care to comment?
Any high flow catalytic converter(s) are allowed, but must attach
within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the single
replacement converter may be located no further downstream
than 6" along the piping flow path from the original exit of the
final OE converter.
One could interpret this as meaning that the inlet of the aftermarket cat can be 6" downstream of the outlet of the OEM cat, even if the car (as in our car) has only a single OEM cat.within six inches of the original unit. Multiple catalytic converters
may be replaced by a single unit. The inlet of the single
replacement converter may be located no further downstream
than 6" along the piping flow path from the original exit of the
final OE converter.
But, I'm new to this rule interpretation business. Anyone care to comment?
I would interpret that to mean the exit of your replacement must be within 6" of the original exit of the last converter... However, it is possible they could allow the inlet to be within 6" of the old exit, but that seems way to flexible to be a Solo rule.
06-22-2009, 05:52 PM
#145
Yeah, that's what I was thinking. But, they specifically state that, for the case of replacing multiple OE converters with a single aftermarket, that the inlet of the aftermarket coverter can be as much as 6" downstream of the outlet of the final OE converter.
It seems strange that the dual-to-single conversion would have this flexibility, but not the single-to-single.
It seems strange that the dual-to-single conversion would have this flexibility, but not the single-to-single.
06-22-2009, 06:37 PM
#148
that was the discussion we had when I was on the committee, there was all kinds of discussion on using where the brick ends, but it's not easily determined etc.
and yes Jason, it was 6" from the original exit to the modified inlet, the issue is what is the cat and where are the inlet/exit ...
I would just mount the aftermarkt cat in the OE cat area myself, or rather that's what I did.
and yes Jason, it was 6" from the original exit to the modified inlet, the issue is what is the cat and where are the inlet/exit ...
I would just mount the aftermarkt cat in the OE cat area myself, or rather that's what I did.
06-22-2009, 08:12 PM
#149
Yes, details do make it easier to understand. Funny how that works. Thanks for the info.
I still think that, given how the rule is currently written, there is room for interpretation. If, in the case of the RX-8, the whole pipe is that cat, then one could argue that we have great lattitude as to where the header ends and the cat-pipe begins (basically: anywhere within the current cat-pipe +6 inches).
I'm not saying I'm going to build such an exhaust system, but if there is indeed value in lengthening the headers, somebody might else might, and therefore I think a clarification is in order, assuming my interpretation is not in keeping of the original intent of the rule.
I still think that, given how the rule is currently written, there is room for interpretation. If, in the case of the RX-8, the whole pipe is that cat, then one could argue that we have great lattitude as to where the header ends and the cat-pipe begins (basically: anywhere within the current cat-pipe +6 inches).
I'm not saying I'm going to build such an exhaust system, but if there is indeed value in lengthening the headers, somebody might else might, and therefore I think a clarification is in order, assuming my interpretation is not in keeping of the original intent of the rule.
06-22-2009, 08:16 PM
#150
Probably the one swoope is using in this thread:
https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/hi-flow-cat-buy-not-pipe-cat-just-cat-136242/
https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/hi-flow-cat-buy-not-pipe-cat-just-cat-136242/