Everything I've learned about suspension in the past 5 years
11-29-2009, 12:38 PM
#26
Eric
thanks man--good advice
T1--so that why one person was telling me to get braking done early for turn one.maintain speed and even though you will enter, thinking you are going to fast --the banking will catch you.
I do see people appexing it too soon.
Not hitting bump stops but by studying pics there is a lot of compression going on.
T-6 people do overbrake-- thats why i like to trail brake 6! Now it all depends on traffic of course but i like trailbraking 6 , getting 7 lined up asap and then nailing it. My turn in to 7 is much more "abrupt" (only word i know to describe).
I never thought about left footed braking there with some throttle--good idea.
i am getting getting heavier springs also--never upgraded my suspension after I increased in power--what wasnt a problem before---now is. Chasing monkeys at times. Familiar?
T-12 well--- it's T12 and I am a Puss with a clean drivers seat. Ha--i will catch them on the front straight.
Ever since a Mustang cobra spun in front of me almost at entry (100+mph) --went off track to right and then back across track to left---i have been a little more leery of that area. I think I had a short run of ventricular fibrillation then---and it happened so damn fast.
I am well aware of the pick a spot technique---damn that blond on the grid out wall.
Please join us for our group photo for the calender --we are going to line the cars up --maybe on the skid pad. You can drive mine over to it with me.
OD
thanks man--good advice
T1--so that why one person was telling me to get braking done early for turn one.maintain speed and even though you will enter, thinking you are going to fast --the banking will catch you.
I do see people appexing it too soon.
Not hitting bump stops but by studying pics there is a lot of compression going on.
T-6 people do overbrake-- thats why i like to trail brake 6! Now it all depends on traffic of course but i like trailbraking 6 , getting 7 lined up asap and then nailing it. My turn in to 7 is much more "abrupt" (only word i know to describe).
I never thought about left footed braking there with some throttle--good idea.
i am getting getting heavier springs also--never upgraded my suspension after I increased in power--what wasnt a problem before---now is. Chasing monkeys at times. Familiar?
T-12 well--- it's T12 and I am a Puss with a clean drivers seat. Ha--i will catch them on the front straight.
Ever since a Mustang cobra spun in front of me almost at entry (100+mph) --went off track to right and then back across track to left---i have been a little more leery of that area. I think I had a short run of ventricular fibrillation then---and it happened so damn fast.
I am well aware of the pick a spot technique---damn that blond on the grid out wall.
Please join us for our group photo for the calender --we are going to line the cars up --maybe on the skid pad. You can drive mine over to it with me.
OD
11-29-2009, 01:09 PM
#27
So what does this have to do with upper control arm Delrin? Well, we figured out during the rebuild of one of our car's front suspensions that the control arm assembly (front upper control, spindle/upright, and lower control arm) did not freely travel up and down. We noticed this with no swaybar attached and the shock removed. Closer inspection showed us that the upper control arm bushings get pinched when they are tightened down. Noticed I said tightened down and not over-torqued. We had Delrin bushings made to allow for more free movement. Currently you can torque these guys down to spec and the suspension freely moves up and down when using your little finger.
Thanks for sharing!! This thread is downright amazing.
11-29-2009, 01:20 PM
#28
Power!!
As always great stuff Eric. I really appreciate your willingness and openness sharing your knowledge and experience with the rx8 community. I still have to go back and read more but just wanted to chime in and say thanks!
12-06-2009, 10:10 PM
#30
Power!!
You put a zip tie around the shock rod against the shock body in the resting position. Then after you do a hot lap you Check the position of the zip tie on the shock rod to see how much compression the suspension has gone through and whether or not you're bottoming out your shocks. If the zip tie is up against the bump stop you're bottoming out your suspension.
Last edited by shaunv74; 12-06-2009 at 10:13 PM.
12-07-2009, 08:40 PM
#32
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Thread Starter
You put a zip tie around the shock rod against the shock body in the resting position. Then after you do a hot lap you Check the position of the zip tie on the shock rod to see how much compression the suspension has gone through and whether or not you're bottoming out your shocks. If the zip tie is up against the bump stop you're bottoming out your suspension.
If you find out you are running out of shock travel (because the zip tie is wedged down into the bump stop) you may have an easy opportunity to fix this without raising your ride height. Depending on the size of your shock bump stops (the rubber doo-hickies that your shock bodies hit if you bottom out) you may be able to cut down your bump stop to increase your ride height. Several bump stops are quite large. You only need an 1" or so.
Symptoms of bottoming out your shocks can be:
-Can wants to go to snap oversteer when throttle applied in slow and tight corners
-A large "WHA-BOOMP" if you hit a big bump or curbing on the track
-Very low ride height and unpredictable handling characteristics when the car is in roll
-Shocks leak
-Shocks can be easily extended and retracted by hand.
Many of the really big boy race teams won't use bump stops. Here in Indianapolis there is a shock repair facility that does Rolex, Indy, NASCAR, NHRA....... they know their stuff. I have been told that these teams treat their shocks as good as or better than their engines. Typical rebuild process to insure shocks work properly is 2X / season.
12-07-2009, 09:26 PM
#34
I suppose he might regret that, but maybe not
I don't agree with not running them, talk about your snap oversteer
but I can see if the spring rate is high enough relative to travel clearance you
might get away with it, not in STX on street tires though
bumpstops are one more tuning tool if you're on top of your game ...
.
I don't agree with not running them, talk about your snap oversteer
but I can see if the spring rate is high enough relative to travel clearance you might get away with it, not in STX on street tires though
bumpstops are one more tuning tool if you're on top of your game ...
.
Last edited by TeamRX8; 12-07-2009 at 09:33 PM.
12-08-2009, 06:01 AM
#36
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Thread Starter
Just to clear this up for those reading who may be new(er) to suspension-----if your car is running out of suspension travel and you've concluded that your hitting your bump stops, you MAY have the opportunity to reduce the size of your shock's bump stop by cutting them down. This would give you that much more travel. In otherwords, if you're gettin' down with yo car at da track and find the right or left rear zip tie on the chrome shock rod to be wedged down into your bump stop, cutting the top 1/2" off your rubber bump stop will give you 1/2" more travel. Personally I like to make sure we are not touching our stops.
A smart car owner with adjustable ride height shocks would start with his/her car at a higher or more stock height, drive the car with the zip ties and do an analysis. Step 2: lower the car 1/2 to an 1". Repeat process. For the few aftermarket RX-8 coilovers I've seen, the rear appears to be the ride height issue to look at closely.
Currently we are having one set of shocks rebuilt. I'll take some pics and post next week.
A smart car owner with adjustable ride height shocks would start with his/her car at a higher or more stock height, drive the car with the zip ties and do an analysis. Step 2: lower the car 1/2 to an 1". Repeat process. For the few aftermarket RX-8 coilovers I've seen, the rear appears to be the ride height issue to look at closely.
Currently we are having one set of shocks rebuilt. I'll take some pics and post next week.
12-09-2009, 01:45 PM
#37
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This was a really good read! love that you share some background info aswell.
You should write suspension/chassis tech. articles for a carmag or something, I would buy it direct.
You should write suspension/chassis tech. articles for a carmag or something, I would buy it direct.
12-10-2009, 05:41 AM
#39
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12-10-2009, 10:05 AM
#40
I'm looking over what you're sharing with us (thank you for all of this, by the way) and attempting to wrap my head around it to allow me to see what I can use with regard to rally cross, which I freely admit is a hugely different animal than road racing (my RX-8 is also a daily driver and I'm too much of a coward for wheel to wheel racing).
I very much appreciate your input and insight.
I very much appreciate your input and insight.
12-10-2009, 11:37 AM
#41
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Just read your whole post and I wanted to say thank you for a very informative and entertaining read. Although I am not ready to apply any of the knowledge presented, I certainly appreciate all of the work and research.
12-11-2009, 02:41 AM
#43
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I just took my bumpstops out and, well, at my ride height, blew two of my dampers!
I wish some of those details would have been clarified to prevent me from applying the technique to the wrong application.
As if it hasn't become redundant enough, great thread. I look forward to learning and applying as much as the competition section has to offer in this upcoming season. Thanks to all of you who contribute valuable information!
I wish some of those details would have been clarified to prevent me from applying the technique to the wrong application.
As if it hasn't become redundant enough, great thread. I look forward to learning and applying as much as the competition section has to offer in this upcoming season. Thanks to all of you who contribute valuable information!
12-11-2009, 06:36 AM
#44
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I'm looking over what you're sharing with us (thank you for all of this, by the way) and attempting to wrap my head around it to allow me to see what I can use with regard to rally cross, which I freely admit is a hugely different animal than road racing (my RX-8 is also a daily driver and I'm too much of a coward for wheel to wheel racing).
I very much appreciate your input and insight.
I very much appreciate your input and insight.
Background: We ran a K&N type filter in front of the radiator exposed to the elememts for both Daytona and Homestead Speedway. You'll recall that there is this thing in Florida called SAND. The motor injested sand and toasted her big time. Twice. Found sand in the oil pan. Thought it wa a fluke first time and later confirmed with Haskill from SpeedSource that the #69 and #70 Grand-Am 3 rotor GT run a STOCK RX-8 PAPER AIR FILTER ELEMENT. David told me that when they ran a mesh/metal type air filter they also injested sand at Daytona and Homestead and had motor issues.
Therefore, rally = dirt (I think) and dirt = not good. There you go.
Meyer out
12-11-2009, 08:23 AM
#45
now that is interesting--since mazdaspeed sells a cai with a a k&n type filter you would think it would not be a problem. I was just about to go that route, but now I dont think so.
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
12-11-2009, 09:27 AM
#46
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now that is interesting--since mazdaspeed sells a cai with a a k&n type filter you would think it would not be a problem. I was just about to go that route, but now I dont think so.
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
12-12-2009, 04:04 PM
#47
Registered
Thread Starter
now that is interesting--since mazdaspeed sells a cai with a a k&n type filter you would think it would not be a problem. I was just about to go that route, but now I dont think so.
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
Heck if it is picking up sand , then there are other smaller stuff out there that it is also getting.through.
A paper type filter, on my particular type intake ,messes up my maf to the point my a/f's goes crazy so i dont have a choice. Guess i need to make sure it is properly oiled more often.
A lot of people are running the open mesh type filters. Is this something that needs throwing out there?
OD
There are two versions of this. Both are made by AEM.
12-12-2009, 08:59 PM
#49
This thread is an excellent and entertaining read. Thanks, Eric!!!
I ran into this a bunch of times with the Koni guys. It pretty much made the AccessPORT the only solution if you couldn't budget the Bosch system, which many of the teams didn't want to spend. They didn't see the benefit.
Interesting. Several of your competitors consistently made your 5th gear power level on multiple motors in multiple chassis. I wonder what the difference was?
The AIM is incredible, but it is very important that the OE wiring harness is essentially intact or it wont collect OBD2 data correctly. It also monopolizes the CAN bus, so realize that nothing else will be able to make requests while the AIM is operating.
Hmm. I wonder who your rental came from... 
So, is this to say that the spring rates weren't actually that crazy? For a race car, they don't really seem that stiff to me - but I am absolutely NOT anything remotely resembling a suspension guru.
I'm running 400/375 on the car and they feel like mush to me. I'd think only a 50% increase in the front and less than 25% in the rear wouldn't be "crazy". I was thinking something in that range for my car (11k and 8.3k)! lol
Yeah - the AEM is an oil-less cloth filter. I'm not sure what is going on here.
I ran into this a bunch of times with the Koni guys. It pretty much made the AccessPORT the only solution if you couldn't budget the Bosch system, which many of the teams didn't want to spend. They didn't see the benefit.
2007 Grand-Am Koni Daytona.... Rent an RX-8 from a Koni team. ... Car spins out. Brakes lock up. I figure out that me and my crew know a lot more than the team I'm renting the RX8 from. My guys find issues with the car and suspension. They tell me the car is unsafe and since I trust them with my life I follow their advice. Safety is # 1. The ABS locks up at about 120 going into the bus stop. Car spins. Backs into tire wall. I'm two seconds a lap off my 17 year old co-drivers pace. Turns out the suspension is whack, sway bar disconnected, one rear wheel has huge toe out, ABS unhooked--note to self------very important.
I am running the SpeedSource 3 piece front bar with Alum. arms, Mazdaspeed rear swaybar, Koni shocks, Grand-Am spec Hoosiers and some crazy spring rates. I think they were 600F and 450R. ...At the end of the day we figure out that we are just barely hitting the rear bump stops which causes the car to go directly to oversteer.
I'm running 400/375 on the car and they feel like mush to me. I'd think only a 50% increase in the front and less than 25% in the rear wouldn't be "crazy". I was thinking something in that range for my car (11k and 8.3k)! lol
Yeah - the AEM is an oil-less cloth filter. I'm not sure what is going on here.
12-12-2009, 10:21 PM
#50
ok --so basically speaking then the AEM and the mazdaspeed cai air filters are paper types which means that sand is NOT an issue? I know mazdaspeed insists that their cover be used but aem doesnt require one?
Sorry for the highjack--
Robot 1a1998 told me to post
OD
Sorry for the highjack--
Robot 1a1998 told me to post
OD