R sway bar causing understeer?

[TURBO2GO]

I got signed off solo yesterday at my HPDE, and I was pretty psyched. It's a different experience driving alone versus with instructor. I really started to "feel" the car by the 4th event of the day, and was sliding around many turns feeling very comfortable and confident with the car. I am attributing this greatly to the fact that my new Dunlop Z1's felt much more predictable than my old RT615 Azenis. I just LOVE this tire. I was so comfortable in the advanced run group I was passing every car and actually lapped a couple of cars. Some of these guys are in prepped M3's with slicks and gutted interiors. I was really surprised of this, I don't think my driving is all that much better than them, so I am attributing some of this to the car but... I am running street tires and they are on hoosiers! I managed to pass every single car in my run group of maybe 17 cars. The NSX did not let me down... I am sure they got sick of me in their rear view mirror haha

Anyway my question is.... my car does NOT oversteer at all unless it is throttle induced. Going into turns my tires are squealing, the car is sliding, even the rear, but it will never swing its tail out. I used to always be afraid of this, but now knowing when to and not to apply throttle, I feel I can push it much further. I am wondering is this stock behavior, or is the front R sway bar causing this? Does a stock NSX keep its tail tucked to this level? I even slightly increased rear tire pressure but still, it was very well behaved.

I can't even imagine how fast this car could be with R compounds and an unpgraded suspension. If I upgrade to something like a KW, and keep the same spring rate ratio, will it continue this behavior? Is there a reason why I would want more oversteer? I really like how it feels now. Maybe as I get better I won't? Anyway I got a video I will post maybe you guys can comment.

 

[docjohn]

so you figured out the cel issues I would need to sit next to you and drive the car to determine how the car is handling,but it sounds like you are happy/psyched which means I would just keep things as is and work on seat time for next season.

 

[CL65 Captain]

I would leave it as is for now. Over steer is not confidence inspiring, especially in an NSX that likes to keep going once you get the back end to start moving. You can always play with tire pressures to let you make the car more neutral or over steer and that's FREE and should keep you busy for another season. :tongue: I think you are at the 1st plateau in your driving, which the natural tendency is to want to add more $$$ to get you past it. In my case, I switched to R-comps. Now I am back to Dunlops Z1s as for me the expense and PITA to constantly keep mounting new tires wasn't worth it. Keep driving and keep pushing.... I'm sure that you will find the car is a lot more neutral than you think. All of a sudden, you make it past that learning plateau and all with out changing anything.

I had plenty of over steer the day my front sway bar link snapped. No front bar and Dali 1" track bar on the rear. It was fun, it was challenging, but it was only a matter of time before I spun - which I did, twice. Believe me, when you are trying to improve your driving to the next level and really starting to push the car hard.... real hard, you don't want to worry about the back end being the first one to come out.

You want more over steer if you want to play Dukes of Hazzard.

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[EdinKali]

Yes, the front R swaybar will shift the handling more towards understeer.

bigger front swaybar=more understeer(reduces front grip)
bigger rear swaybar=more oversteer(reduces rear grip)

 

[TURBO2GO]

so you figured out the cel issues I would need to sit next to you and drive the car to determine how the car is handling,but it sounds like you are happy/psyched which means I would just keep things as is and work on seat time for next season.

Doc, the CEL thing is real intermittent. Car ran great on track. No misfires at all. I don't know. My mechanic felt it was ok to run. My new NGK 02 sensors turned out to be dead out of the box. NGK has an issue here, they read nothing on the scope either. Put my old 02's in and it's running ok for now. More diagnostics to come but mitch does not think it's ignition. He wants to replace 02's with Acura ones then really check Comptech FPR. I have one more day tomorrow, hopefully it will run well and I will take it back and we will work on the problem.

 

[CL65 Captain]

A little off subject, but as much as you track your car if you don't have TiDave's rear bushings and toe links.... you should. It makes the rear end much easier to feel what is going on with zero decrease in street comfort or noise. just my $.02.

 

[WingZ]

More than likely Dave it's because the spring/shocks are not tuned for the R sway. Remember that bar is based on a total suspension that is much stiffer than stock.

No idea how it works with the KW's but works great with my Todas which are a bit stiffer than the Type R set up.

 

[Liquid]

So does this mean I can get my ignitor box back now?

 

[RStom - Hungary]

A little off subject, but as much as you track your car if you don't have TiDave's rear bushings and toe links.... you should. It makes the rear end much easier to feel what is going on with zero decrease in street comfort or noise. just my $.02.

Where can I get those???

 

[TURBO2GO]

Captain, you mean the non-compliance rear beam and non-compliance toe links? what about the front pivot clamps? are those necessary at my stage? I will try to do these for next season, I am done for the year.

Frankly after my last day, I am having second thoughts on touching the shocks/springs. I think a better alignment might be in order and I need to play with tire pressures. I felt like even as is, there is still a lot of learning to be done by me before I change either suspension or brakes. I was in run group 2, (0 being instructors) and all weekend I was not passed one time. I would count 7 cars ahead and ask myself how many laps before I could catch him, and I would... I think honestly most of it may be the car. It just is a faster car than most of the M3's and WRX's. They all told me I need to be in 1 and not 2, but I still have a lot of room for improvement.

The biggest help to me, I felt... was the addition of the Dunlop SS-Z1 over the RT615. They break loose in such a mild progressive manner that it gave me a ton of confidence to push harder. I was in a lot of slides, then I would correct next time around. The car never barked back or bit me. If its understeering, it feels OK to me.

 

[FXMDBilly]

I agree the change in tire is HUGE. the 615 dosn't give much feedback and isn't confidence inspiring unless track temps are pretty cold. Any warm, let alone hot temperatures and the 615s are just greasy.

***What is your alignment, tire pressure, and tire size F&R?

-alignment will greatly determine the balance of your car and the way it reacts. No point in buying things if you're alignment is the cause of your problems.

 

[Prospeed]

What year rear sway bar do you have? I also had major understeer problems when I first installed the front NSX-R sway bar on my 91 with the smaller rear sway bar. I countered it with the 04 rear sway bar and that made the car a lot more neutral and I've been happy since. It was 19.1 instead of the stock 17.3. It was only $86 bucks from the dealer If I remember correctly. Worth the mod. Give it a try! If you go with NSX-R rear sway bar which should induce a lil more oversteer but I prefer A neutral car slightly leaning towards understeer.

 

[e.pie]

What year rear sway bar do you have? I also had major understeer problems when I first installed the front NSX-R sway bar on my 91 with the smaller rear sway bar. I countered it with the 04 rear sway bar and that made the car a lot more neutral and I've been happy since. It was 19.1 instead of the stock 17.3. It was only $86 bucks from the dealer If I remember correctly. Worth the mod. Give it a try! If you go with NSX-R rear sway bar which should induce a lil more oversteer but I prefer A neutral car slightly leaning towards understeer.

there is also the zanardi/type-s rear sway bar as well

 

[TURBO2GO]

My rear sway bar and the type R sway bar are already identical from what I was able to research. My car is an 05 guys, its in my signature! :tongue: But the factory 05 sway bar is definitely thinner than the type R bar. If my sways are identical to the Type R now, the rest can only be alignment settings and shocks/springs. I never tracked my car bone stock, so I don't know and that is why I was asking.

Billy my alignment settings are factory standard 2005 settings, I don't know the details, but can give specs to align to next time to my mechanic. My tires are stock 17" sizes, 215 and 255's. I am keeping air pressure at the recommended cold of 33/40. When they really heat up during the day, I will take some air out mid day and get it around 35/42 or 37/45. I have seen them go slightly higher but I take some out.

Other than the R sway bar, everything is just stock as can be.

My last worthy mods were the DF bucket for the vented R hood which really reduced my hood flutter at speed and kept the car cool as can be, and the STMPO front bar which honestly... makes the factory R chassis bar feel like a joke.

I have a nice HD video of my first solo run, so you guys can see/hear what I am doing, but the thing was in a sony HDVC file or something and I have to convert it to avi... its only been 10 hours on my compter now converting a 30 minute video. This sucks. I hope that Aiptek captain uses is in a more normal format this conversion BS sucks.

 

[docjohn]

As you get faster you really need to keep on those rear tire pressures.The fact that you said you measured the pressures at "up to 45psi or more" tells me they are more likely 48-50 psi on track.This is because they cool pretty quickly once in the pits and you have done your victory lap:wink: and settled back into your parking spot.Those rear pressures will make your back end really squirly(loose). I also second the rear beam and toe links,many vendors sell these.The pivot clamps are less essential at your level.

 

[FXMDBilly]

Try maxing out front camber (you'll probably only get -1.3 to -1.5*) and reducing rear toe in a little.

Also play with your tire pressures. I've never been one to go with the big front to rear stagger like stock. Street tires like what you run don't like pressures much higher than 40psi. 36-38psi hot is a good target and where many DOT tires make the most grip.

Try starting at 33psi cold all around and shoot for 36-38psi hot. Depending on the handling, start to stagger the pressures to get the balance you're looking for.

 

[CL65 Captain]

I hope that Aiptek captain uses is in a more normal format this conversion BS sucks.

The Aiptek stores in .mov format which if you have a Mac is great as it's the native Quicktime format. Walmart and others sell a similar camera called the Jazz which stores direct to mpeg4 (Windows).

 

[Cozmo]

Actually if I remember right the aiptek is actually mpeg4 video with AAC audio inside of a quicktime container. You can use a free program called SUPER to move the stuff into a new (more compatible) container file like mpeg4 without reencoding the video, so it is way fast.

 

[TURBO2GO]

I have yet to solve this camera issue. The Gopro everyone is buying in that big group buy to me is not acceptable. The Sony I tried... at 1080i, my brand new PC cannot display the full video without constantly freezing up on me. Lots of conversion work needs to be done, I want to record in a format I can upload to vimeo or youtube right away. It must have a mic input although someone told me foam on the standard mic will kill the wind noise... I don't know. Captain I didn't know that Jazz was the same as the aiptek. Thanks I will try that.

 

[Cozmo]

Vimeo will let you upload the MOV files from the AIPTEK. I've never tried it myself so I don't know how well it works out. I wouldn't upload anything without editing it first. :wink:

The quicktime from the Aiptek is already extremely compressed compared to the HDV you're talking about.

 

[CL65 Captain]

I have yet to solve this camera issue. The Gopro everyone is buying in that big group buy to me is not acceptable. The Sony I tried... at 1080i, my brand new PC cannot display the full video without constantly freezing up on me. Lots of conversion work needs to be done, I want to record in a format I can upload to vimeo or youtube right away. It must have a mic input although someone told me foam on the standard mic will kill the wind noise... I don't know. Captain I didn't know that Jazz was the same as the aiptek. Thanks I will try that.

Jazz is different company from Aiptek but similar product. Jazz doesn't have a mic input, only the NEW Aiptek Action GVS does. Foam on the mic won't do crap. Tried foam, tried fur like the big boom mikes, tried everything. You aren't dealing with a slight wind like a cam corder standing outside in the breeze - you're talking about 100 mph+. You have to relocate the mic to someplace that isn't getting wind. I tried everywhere - under the seat, under the engine cover, etc. Trunk was the best place.

 

[TURBO2GO]

Lets see if this works. Can you guys see this?

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[CL65 Captain]

yep. works fine.

You go girl! :tongue:

 

[TURBO2GO]

yep. works fine.

You go girl! :tongue:

LOL... that was with a cheap SD card sony cam mounted by a suction cup mount to the back window. The nut was not tight hence the jiggle but overall it made a great recording. Of course I need the trunk mike but the mount is awesome!

So any constructive criticism on what you could see just on that short clip? I have no idea how my driving is because the car is so fast. I pass everyone... 3 days at the track, 4 sessions per day, maybe 8 passes per session... that's like 100 passes and I don't get passed at all. But I wonder how much the car is covering for my mistakes.

 

[I1O101I]

LOL... that was with a cheap SD card sony cam mounted by a suction cup mount to the back window. The nut was not tight hence the jiggle but overall it made a great recording. Of course I need the trunk mike but the mount is awesome!

So any constructive criticism on what you could see just on that short clip? I have no idea how my driving is because the car is so fast. I pass everyone... 3 days at the track, 4 sessions per day, maybe 8 passes per session... that's like 100 passes and I don't get passed at all. But I wonder how much the car is covering for my mistakes.

Very nice run, just having a supercharger with the extra power is great.

Bryan