For Those Using the Toyo RA-1 Track Tire

[nsxtasy]

hmmm, that's interesting, I would like to know more if this is the acceptable option for the missing fender liners...

Docjohn commented in another thread that it's likely that bigger rocks and debris are probably still going to ding/dent the fenders, and I would suspect the same thing.

Of course, if you're going to consider your car a track-only car, you probably don't care if the fenders get dinged/dented...

 

[Peter Mills]

I seem to remember DocJohn telling me that the wheel well liners also keep water out the cabin. Apparently John had to drive in the rain and water came through the wheel well on the inboard side of the door seals.

 

[docjohn]

Yes water did track into the door seals.At this point I keep the superior and posterior plastic liner but have seen no ill effects from leaving the front "vaned" liner off.The exposed fans dont seem to be too chewed up.

 

[Hrant]

Reviving an old thread instead of starting a new one ........

Yesterday, I "finally" transitioned to R compound tires using the RA1 at Infineon. I knew going-in that this was a slippery slope but after holding off for over two years, it was becoming quite embarrassing to keep up with the local smack talking boy racers :tongue:

I opted for the 205/40/17 with 255/40/17 since I had a great buy on a second set of 17/17 OEM wheels. Reading the above posts, I confirmed a few things and I have a few more suggestions.

The tires were not shaved. I had the tires mounted at AIM at Infineon (Ken, 2slow2speed, thanks for the ride, and Steve thanks for hauling my old tires back :wink and immediately took it on the track. Right out of the box, I could tell the car was handling quite differently based on its prior set up even though I had changed the alignment in prepartion for the RA1. See discussion in this thread: http://www.nsxprime.com/forums/showthread.php?t=65233

The steering was more sensitive, and the fear of understeer based on using 205 in the fronts was not an issue (also something confirmed by Tom of RP-Motorsports in PMs months ago; thanks Tom). But based on the shops recommendation of starting tire pressures cold 34 front and 36 rear ....... something was wrong since the rear seemed to be unstable and the car's suspension was jerking too much as it transitioned in the turns. The shop recommended running the RA1 at 36 hot front and 40 hot rear. I was at 38 front and 44 rear after the first session Bringing the tire pressures down to 35 and 38 did not improve much the handling.

So we decided to tinker with the rear sway bar which I had on the stiffest position given that on street tires with the Type R front bar I had understeer. Thanks to our Fearless leader Al, and Kip's tools, using the middle hole and running 34/36 hot it improved the car's handling dramatically! Whereas in the earlier sessions I had to tap the brakes between the Ss just to make sure the rear was settled, now I was taking it without braking at almost full throttle in 3rd. Turns 2 and 3a aspired more confidence by attacking them :biggrin:

So the first question I have, what has been the optimal tire pressures that you run?

Using the pyrometer, I noticed that while overall the rear temps across the tire were relatively within 10 degrees difference (150-160), the front insides were way too cold compared to the center and outside edge; like 118 vs 135-140! Ambient temp was in the 60s. Alignment is based on Bilstein lower perch on stock springs, non compliant toe link:

Front
camber -1.9 (the max we could get)
total toe -0.11
caster 8.1/9.1 we had to do this split otherwise the car was pulling to the right

Rear
camber -1.8
toe 0.13

So question 2, is the front tire temp due to the Toyos needing more camber in the front or am I missing something? TIA.

Edit: I should also note that the brake temps were significantly lower (150-200F), and the OEM caliper with new Carbotech Panther Plus front pads and Dali's 2 piece floating rotors (which have seen some 15 track events and turned once already) performed flawlessly! I'm surmising that having R compound tires help bring the rotor temps down since the tires are helping the braking rather than the brakes overwhelming the street tires.

 

[docjohn]

Hrant,I find my car likes ra1 pressures between 36-38 hot front and rear.I don't stagger the pressures like you would with street tires fwiw.Now to the front temps.My car also was running hotter outside temps and starting to scrub the outer tire even though I thought I had max - camber allowable with stock suspension geometry-Type R susp.Well we put the car back up on the rack and found that both front bushings had play in them,meaning I had worn them out of spec,so after replacing I'm back to hotter inner tires.I have realized that if you track these cars enough esp with r tires you will stress the ball joints.I have replaced all the ball/hiem joints front and rear,even the comptech non compliance stuff needs replacement after many years.

 

[NSXDreamer2]

Hrant,I find my car likes ra1 pressures between 36-38 hot front and rear.

Same here, my buddy who track with me all the time had same suspension but more aggresive alignment seems having the best performance at the same pressure either. It's hard to believed, as my car exhibit perfect neutalStreet car handling: minor understeer entering corner (too fast? :tongue: ) and minor oversteer exiting corners, (problem with those 2nd gear, 30-40 mph. tight ones)… While his had crisp turn in yet having problem keeping the rear end planted at exiting… granted our driving styles are different…

You should have already known it, but your full tread RA1 really won’t give you any good feel but just make sure you wear them down a little bit, I guranteed you’ll love it.
I had posted before, but with the Recaro seat, full tread RA1 with TeinRA, I instantly got 3 seconds better at Pacific raceways without even pushing it. (I haven’t trust the grip yet.)

Fast forward 3 more track days, I got 6 seconds improvement over last year “best lap time”, and consistently driving at 1:43 to 1:45 in traffic. Best lap time so far is an unconfirmed (Video taped timing) low 1:41… with worn down RA1 (about 10 track days).

 

[Hrant]

I had the 3 seconds in the bag already after the first session ....... :wink:

I agree re tire pressures. After some experimenting - rather than just relying on tire manufacturer recommendation, "around" 36 seems to make more sense. Next time I will keep the fronts/rear the same and see how it handles. But I was surprised how adjusting the sway bar by one hole could make such a noticeable difference. Once I get more comfortable with the tires I may try the last hole (softest) on the rear too.

 

[kenjiMR]

I had the 3 seconds in the bag already after the first session ....... :wink:

I agree re tire pressures. After some experimenting - rather than just relying on tire manufacturer recommendation, "around" 36 seems to make more sense. Next time I will keep the fronts/rear the same and see how it handles. But I was surprised how adjusting the sway bar by one hole could make such a noticeable difference. Once I get more comfortable with the tires I may try the last hole (softest) on the rear too.

Which sway bar do you have? What position is it actually on?

 

[Hrant]

Hi Kenji. The sway bars are adjustable Comptech; but I also have both the Type R bars. Initially the car was set up with both sway bars on stiffest positions. The rears were then put on the middle hole while leaving the front on the stiffest (the farthest hole from the end). I am sure tire presuure also helped a lot.

 

[kenjiMR]

Hi Kenji. The sway bars are adjustable Comptech; but I also have both the Type R bars. Initially the car was set up with both sway bars on stiffest positions. The rears were then put on the middle hole while leaving the front on the stiffest (the farthest hole from the end). I am sure tire presuure also helped a lot.

I have the Dali Track/Street bars, and I had them set to full soft in the rears and full hard in the front when using S03s. It hooked up pretty good, but unless I test a lot more its really hard to know the optimimum under/over steer setting... plus my suspension was TEIN RA (not so good). Now I'm back to HR+Koni with crap tires (Falken GR-Beta) and I run the rear bar full soft and front bar in the center. I wonder how the Dali bars differ from the Comptech, I can't recall anymore. Did you try using the softest setting as well?

 

[NSXDreamer2]

Kenji, does H&R and Koni yellows actually better than TeinRA?

I kind of doubt my skill level, as everyone who drives fast hates the teinRA and I just absolutely loved it... and I drive on bumpy tracks too. ( I know I got a lot more to learn in terms of driving skill and knowledge...but :redface

my car is a 91 with no other suspension mod but the TeinRA and I track with stock setup, maybe it makes a difference?

 

[docjohn]

The spring rates with the ra are what most of us have a problem with-10front 12 rear.That said i did drive a car with them at xpo and found the handling surprisingly good at firebirds tight track,I just stiffened the front shocks to 20 or therabouts and the rears soft at like 6 to try and ballance those spring rates,well,I liked it.I used to run the HR/koni combo for many years and I would say the tein set the way I did was better than I ever recall the HR/koni combo to be.

 

[Hrant]

Allen Shim on these forums has also tinkered with this set up using the Tien and the RA1 tires. I believe he is now tracking without the rear sway bar. Hopefully he can post his assessment as well.

 

[Andrie Hartanto]

The spring rates with the ra are what most of us have a problem with-10front 12 rear.That said i did drive a car with them at xpo and found the handling surprisingly good at firebirds tight track,I just stiffened the front shocks to 20 or therabouts and the rears soft at like 6 to try and ballance those spring rates,well,I liked it.I used to run the HR/koni combo for many years and I would say the tein set the way I did was better than I ever recall the HR/koni combo to be.

Try to measure it with lap times, and you might think differently.

The Tein is deceiving. It felt good as it stiff and transmit everything well. But they are not fast enough in response. They masked it by running lots of bump and making it stiff.

I tried so many different setup with Tein RA on the NSX. Not running rear bar as well. I couldn't even match my best time with H&R and Koni.

Now the Comptech pro on the other hand was about 3.5 sec faster than the H&R and Koni.

Keep in mind, data gathered by non-experience driver will only serves to confuse you. Same thing like gathering bad data or with bad method.

Lots of people think they are good driver. In reality they are still far from able on collecting reliable data. This requires not only good driver, but tons of experience as well.
Before I had the experience nor the ability, I hired professional that knows how to do this things. That is the only way to move forward fast. By guessing and trying it out yourself, it is very easy to go the wrong way and don't realize it until it is too late.

 

[docjohn]

Fair enough Andrie,but I think I can tell when a car is ballanced and not evil handling.Thus my statement was not geared tword fastest at the track,only with overall ballance.That said my times with a stopwatch trackside were pretty close to the times of our known fast guys with well sorted suspension.I hope you will be at Sebring this year,so we can play!I'll tape a newspaper to my rear bumper so you'll have something to read during the instructers' sessions:tongue:

 

[Andrie Hartanto]

John,

I certainly don't mean it that way. Some people has better ability on adapting to their equipments. This doesn't mean he is a bad driver, but he certainly not a good test driver. Test driver should know or can detect all the small changes.

I certainly hope I can make Sebring. But the likely hood is very slim. Firstly, I no longer an NSXCA member. And for some reason, they didn't invite me to instruct anymore which I don't understand why since the club regularly use non member to instruct. Secondly, if you see my schedule on my website . I have a race on Sat and Sun before NSXPO. And a week after is Laguna Seca Speed World Challenge.


I like your smack talk though. If you come to this side of the country, I'll let you drive my race car and see if you can get within 2 sec of my time on the same day

 

[kenjiMR]

Kenji, does H&R and Koni yellows actually better than TeinRA?

I kind of doubt my skill level, as everyone who drives fast hates the teinRA and I just absolutely loved it... and I drive on bumpy tracks too. ( I know I got a lot more to learn in terms of driving skill and knowledge...but :redface

my car is a 91 with no other suspension mod but the TeinRA and I track with stock setup, maybe it makes a difference?

The TEIN-RA definitely gave me more confidence in driving the car fast, I had Eibach progressive spring with Koni prior to that. That setup REALLY sucked. The HR+Koni is seems softer, but I haven't tested thoroughly like Andrie to determine which is actually faster. I just like my HR+Koni because it still turns good and the car doesn't do resonating bounces on the street like with the TEIN-RA.

 

[2slow2speed]

The steering was more sensitive, and the fear of understeer based on using 205 in the fronts was not an issue (also something confirmed by Tom of RP-Motorsports in PMs months ago; thanks Tom).

Hey Hrant,

Sadly it will only be a matter of time before your car will start understeering with the 205's up front, there is simply not enough rubber there

Ken

 

[Hrant]

So who has some cheating notes to overcome the laws of physics :tongue:

I can already see Andrie sending me a PM for his private coaching expertise and suspension set up tuning ........ :biggrin:

 

[Andrie Hartanto]

It's a slippery slope, eh Hrant?

 

[Hrant]

Why do you think I held off for over 2 years ......... as I said, to keep up with the Jones' is becoming embarrassing. Talent by itself is no longer enough, I now need to cheat sicne I can't compete with boy racer funds :wink:

 

[RP-Motorsports]

Hey Hrant,

Sadly it will only be a matter of time before your car will start understeering with the 205's up front, there is simply not enough rubber there

Ken

Then you are not pushing the rear enough! :wink:

We do run 235-40-17 when all possible, but many people are running oem wheels. I can run a 205 with a perfect line by driving my NSX as hard as a FWD to get a bit of rotation. You need JPM reflexes though, and if you don't have them, get some Sorcery fenders and put 265's up front! :biggrin:

I always try to get people to upgrade to a 17x8.0 when ever possible, and to stay above a +42mm offset.

 

[2slow2speed]

Then you are not pushing the rear enough! :wink:

We do run 235-40-17 when all possible, but many people are running oem wheels. I can run a 205 with a perfect line by driving my NSX as hard as a FWD to get a bit of rotation. You need JPM reflexes though, and if you don't have them, get some Sorcery fenders and put 265's up front! :biggrin:

I always try to get people to upgrade to a 17x8.0 when ever possible, and to stay above a +42mm offset.

Hey Tom,

You're forgetting that I am firm believer of the "cheating bastards" philosophy when it comes down to tracking

So I watch plenty of videos from various makes/model of cars at the various tracks that I frequent. Seen plenty of videos of Honda Challenge cars as well (including the good ones where Andrie places and the ones where his car is a DNF), so I think that I know what you are referring to, please correct me if I'm wrong.

Let's take for example a 90 degree turn, you know that there comes a point though that the front tires are so hot/overworked that no amount of trail braking (or threshold braking) combined with lift throttle oversteer can get a car to rotate reliably at the same spot as when you started the session at a given turn entry speed.

So you are left with 2 choices: don't go in as fast as earlier in the session, or change your turn-in point way back so that it gives enough time for the front tires to slide for a while while braking and for them to finally hookup to initiate the turn and then to allow the lift throttle oversteer to help in rotating the car, it can be fun but it's not the fastest way to go around the track

Same thing goes with those constant/decreasing/increasing radius turns, someone with *more* grip will more than likely overtake you either from the outside or the inside if they are determined and if there is enough space even if you use plenty of left foot braking/throttle steering to keep the car on the "line" by rotating it constantly with the brakes/throttle.

Hopefully you agree, or perhaps you subscribe to nsxtasy's view that wider tires can't possibly account for faster laptimes hehe (just teasing you nsxtasy , I remember a thread that you and ponyboy had way back on that topic!)

Then again this might be all moot, it took 2 years for Hrant to maximize the street tires, so maybe it will take another 2 for him to max out the R-compounds (just teasing Hrant )

Ken

 

[Hrant]

Easy Ken, easy ........ just remember who your friends are :biggrin:

Sure it took me 2+ years (more like 3), and some of those tires had 40 heat cycles on them But in those 2+ years I was able to keep up with most NA1/NA2 cars - some even with R compounds, and Al still couldn't pass me on the straights :biggrin: :tongue:

 

[NSXLuvr]

Its 8 months till NSXPO and the smack talk has already started.:biggrin: :biggrin:

btw, any other feeback on RA1's would be appreciated.