Jason sold all the parts from his STX set up? Will he not be in STX next year?

 

I read the article last night and thought some of the suspension info was interesting. I’m running softer spring rates (448 F/280R), but more bar (Progress front bar, stock RX-8 rear bar). I've toyed with the idea of no rear bar or an MX-5 rear bar as well. I had a Progress rear bar on the car when I first added the coilovers, and the car works much better with the softer OEM rear bar.

I’m also running camber numbers much closer to George than what Jason was using. Based on my past experience in SP, once you can optimize the spring and swaybar rates, non-Mcstrut cars typically don’t need that much camber to make the tires work properly. I was assuming that the lower overall grip with street tires would mean lower camber numbers as well.

I wonder if Jason had a Stock class alignment mentality (max the front camber and adjust the rear from there), or if there was some testing done to arrive at those numbers? Hopefully he’ll chime in.

I can get 3.0 out of the front with my current ride height settings, but that just seems excessive to me on a street-tired, non-Mcstrut car.

 

I've chosen to try an adjustable MX-5 rear bar on my car next season. I'd like to balance the car primarily with my spring rates, but have a adjustable rear bar that's soft enough to truly fine tune the handling.

 

Which adjustable MX-5 bar are you looking at? Be aware that some of the aftermarket adjustable MX-5 bars are stiffer than the comparable RX-8 products.

 

I've already purchased it and installed it on my car.

I'll shoot you a pm about it Iain.

 

No, I didn't forget that. I was just comparing notes with Suspension, who stated that his car has a higher ride freq and was stiff on the street. My car is not that stiff on the street, so it makes sense the ride freq is closer to 2 Hz as opposed to 2.6.

However, if you are correct and we shouldn't go much above 2 Hz, it would seem that an STX RX-8 can be quite liveable day-to-day. In fact, the seat made a bigger difference in ride quality than the KWs did.

Of course, a bushing set could change all that, assuming somebody comes up with a setup that actually helps performance...

 

What F&R swaybar rates did you use in your calculations?

 

None - this is just ride frequency (i.e., ride rate) which is controlled primarily by the spring rate (and tire stiffness, if you want to be complete).

Now, to calculate the roll rate, or single-bump ride stiffnes, you need to consider the ARB as well.

At least, this is my understanding.

 

I'm considering selling my SSR Type Fs with 245/40-18 Nitto NT05s. The wheels are 18x9 and so are STX legal. The 245 width NT05s are probably pretty good for someone who is still coming up to speed. The thread is here: https://www.rx8club.com/showthread.p...56#post3324056

 

23hp and 8 ftlbs torque? Doesn't really seem worth it to me. Don't think I'll be doing any power mods any time soon.

 

As was stated in the article, chassis setup is where most of the time is. The power mods will only get you a few tenths, which really only matters if you are expecting to compete at the national level.

I think the power mods are also worhtwhile on the street, in terms of the fun-to-drive factor, but that's an entirely subjective matter, and since this is a racing forum I won't go into that here.

 

Just finished reading Jason's article in Sportscar... Thats a great article for sure. Definitely gave me some decent ideas and things to look out for. Did anyone get to hear his car though? Was wondering what he was getting for sound check, as I want to go back to a single muffler setup, but I know I need to do custom so not sure what I'd be looking at. Also... no rear sway and -2.5 camber in the rear? Hmm...thoughts?

 

Brian Harmer posted the sound readings taken @ Nats on sccaforums several weeks ago: http://sccaforums.com/forums/storage...20Readings.pdf

Jason and Jennifer had the following readings on his RX-8:

STX 48 103.1 101.6 103.4
STXL 48 101.6 99.3 102.7

In regards to his camber, that worked for him so be it. I know Jason mentioned to me that he was having a lot of wheelspin when trying to put the power down on street tires. I personally will start out with roughly -2.5 Front/-2.0 rear.

 

That's surprising for the camber only because I ran -2.0... then -2.5..and it just was terrible for getting power down to be honest. At least, that was my take on it. When I put my rear to -1.5..it felt much, much better and I definitely can tell I'm getting the power down. Perhaps because he's running 265 he could run the more negative camber and not risk losing tire width then.

As for the sound ratings... is there no sound limit at nationals? We have a 91DB limit from 75 feet away. Like I mentioned, looking to build my own single exhaust setup, but I need ideas and all... and if those sound ratings are from 75 ft away.. noooo way I can run that setup then.

 

Marc,

There were no sound limits at Nats this year (new site), but there will be some enforced next year. IIRC, the sound readings from Nats were taken @ 50ft.

 

Hmm...that's still pretty loud even from 50ft. Good to know though, thanks again. Guess I'll have to keep rethinking an ideal single exhaust setup that is quiet.

 

Since you're in SM and don't need to run a cat, you could run a dual resonated mid-pipe (like the BHR) along with a different muffler (like the one Jason went with).

I personally plan to add a Vibrant 3" resonator to my Racing Beat mid pipe (along with the 100cpi cat). I use a corksport dual catback like GeorgeH. I'm hoping that'll be enough to keep the sound down. I plan to do the Finger Lakes NT next year and they have sound limits at that event...

 

Well I'm running BHR's midpipe right now... thing is when I ran a header, BHR midpipe, and HKS exhaust.. I was still too loud. So, I had to go back to stock catback. I went to stock header too as the flange of the crap header I was running was warped anyways. So thats why I'm trying to think up a new project.

 

Mod Edit: The title of this thread was changed at the request of the "chiketkd".

 

Gotcha Marc. How loud is your car with the current set-up?

One reason why I'm sticking with a dual exhaust set-up is for the added sound suppression over a single exit.

Btw, in the December Fastrack, the following is mentioned re: sound:
IIRC, Appendix I states a limit of 100dBA @ 50ft.
Excellent! Thanks Al.

 

So that translates to 100dba from 50ft away at any SCCA site...?

As for how loud it is NOW with stock header, BHR midpipe, and stock catback ... well as Ray mentioned, 1db louder than stock? With a light huffing sound because it's just a midpipe..lol. But it sounds good and all, but I'm looking for the gains as much as possible really, and weight reduction.

 

Not any scca site - only national events in 2010 and onwards (national tours, pro solos, nationals, pro finale).

I'd try a lightweight dual catback. Or make a custom single exit that angles down to the ground.

My former custom exhaust which was a straight pipe and resonator after the cat, was between 91-95 dBA @ Nats. When I ran my Corksport at Finger Lakes, it was in the low 80's (maybe in high 70's) dBA at 75ft.

 

Really? Thats really impressive. No header though, right? Just stock? I totally prefer a single exhaust due to weight and look..but I guess I just have to bite the bullet on this one.

 

Yup - I was in B-stock though, so stock header, midpipe, and my Corksport catback. We ran the Corksport and not our usual race pipe catback, as we wanted to be sure we met sound. It was almost laughable how much under we were.

Btw, they had the meter incorrectly placed on Day 1 and readings were a bit high (iirc my car was around 90 dBA on day 1), but by Day 2 they had fixed the issue.

 

Well I called Enkei North America today and they had someone in their warehouse weigh the 18x9.0" RP03. The weight for that wheel is: 19.95LB

I'm starting to reconsider 17" wheels...
Where's the clearance tightest on your set-up (17x9 +45 RPF1)? Between the barrel and the back of the caliper or between the spokes and the side of the caliper?