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The Official "RX8 in DSP" Thread

Old 08-23-2013, 03:29 AM
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Smile The Official "RX8 in DSP" Thread

This is probably my last year running in STX and am likely bound for DSP next year (finances willing). The only "serious" DSP class RX8 I'm aware of belongs to Zelse in the Philly/NYC area for the last several years starting in BSP before this years reclassing (no offense if there are others). Since most RX8s going to DSP will likely be STX converts the likely place to start is with the additional allowances for DSP. The following list is an abbreviated summary of the permitted changes. It's highly recommended that you make yourself thoroughly familiar with the particular details and nuances of the Section 15 Street Prepared ruleset before performing any modifications.



Originally Posted by TeamRX8


Street Prepared allowances above Stock:


Remove A/C components (interior & exterior but heater system must not be modified)

DOT-R tires are permitted

Any diameter or width wheels

Cut or flair fenders to accommodate wheel/tire size

Any high-back seat (no minimum weight limit)

Any steering wheel (no air bag requirement)

front splitter & rear spoiler aero is allowed, but no aftermarket rear wings

A fuel cell is allowed as long as its installation conforms to GCR requirements, the vehicle conforms to SCCA Track Level 3 time trials safety requirements (roolbar ir cage, window nets, etc.) including an installed fire extinguisher, and has at least 80% capacity of the factory fuel tank (S1 is rated 15.9 Gal from Mazda = 12.75 Gal minimum allowed capacity)

Stereo/speakers/amps can be removed (wiring must remain, any resulting holes must be covered)

Any single brake master cylinder or brake booster.

A single bolt-on master cylinder brace is allowed.

A brake proportioning valve is allowed.

No limit on rotor cross-drilling surface area

Brake backing plates can be modified or removed. Brake air ducts are allowed as long as the body/structure is not modified

Steering rack bushings can be changed as long as the metal content is equal or less than OEM

Any ignition system or component is allowed

Any starter or alternator is permitted, alternator output must be equal or greater than OE

Any oil pan, oil pump, oil cooler(s), or oil pump pickup is allowed, including an Accu-sump

Fuel injection and intake manifold are unrestricted, including injectors, rails, throttle body, linkage, pressure regulator, etc.

All emission control devices may be modified or removed, except for wiring harnesses

Intake water injection is allowed

Any fuel pump(s) is(are) allowed, any fuel line is permitted up to 1/2" ID with one supply line, one return line, and an added fitting is allowed at the top of the fuel tank

Any gasoline fuel is permitted including E85 since it's DOT approved

Any radiator is allowed as long as it uses the OE mounts and is equal or larger in core size (S1 core size = 25.50" x 14.50" x 1") (S2 core size = 25.25" x 14.63" x 1.38"), fluid capacity, and dry weight than OE (may serve no other purpose such as allow a cold air intake passage, etc.)

Any radiator fan & shroud is permitted (except flex-fans, not applicable)

Any metal clutch & flywheel is permitted (friction surfaces can be non-metallic i.e. carbon-carbon discs ok, etc.), an alternate slave cylinder/device is permitted (allows conversion from slave/mechanical actuator to full hydraulic direct actuator)

Engine & drivetrain components may be balanced, but not lightened

Intake and exhaust port matching is permitted within 1" of the interface joint

Any aftermarket engine computer is allowed (MoTeC, etc.)

Update/backdate between 2004-2008 S1 and 2009-2011 S2 models
- 4.777 rear gear and finned diff cover
- stronger trans with a slight weight penalty
- upgraded suspension and chassis parts



.

Last edited by TeamRX8; 05-13-2017 at 10:21 AM.
Old 08-23-2013, 06:10 AM
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Been running DSP this year myself @ CT Autocross. Competition is sparse unfortunately. There is another R3 who runs (Goddesshunter) but lately the top podium finish has been going to this slightly modded GTI that runs R-comps and some minor performance mods (and a 6yr vet of autocross). Hopefully soon I can afford myself a set of nice sticky tires.
Old 08-25-2013, 07:33 AM
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Team, find Zealse at Nats and talk to him about how much tire can fit up front in DSP trim. I'd be curious to hear your input and what is causing them to say 285 is the limit. I've not looked to closely at the issue they say limits this.

Having driven the car in BSP form last year, it is a hell of a lot of fun. It should be even better now that he has sorted out some suspension issues and until money allows for a real clutch type diff has put the torsen back on.
Old 08-25-2013, 07:59 AM
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I already know. With the proper offset and some fender clearancing you can get 295s to fit (i have a picture posted on here). My ntention is to run either the 285/30-18 or the 275/35-17 size though. The limit issue most people have is due to wheel offset, as most readily available wheels tend to not have as much offset as you can fit the tire to the inner clearance limit. An example is the Enkei 10" wide RPF1, which is fairly light and low cost, but max offset available is only +38. Once you maximize offset the limitation becomes the tire hitting the back fender/footwell wall at full lock. Steering rack limiters are allowed though. Most people are too scared to cut their fenders, but at this point I don't think it will be necessary for SP.

I've already collected several sets of wheels over the last two years; 17x10 +52, 18x10 +56, and 18x10.5 +43



.

Last edited by TeamRX8; 08-25-2013 at 08:03 AM.
Old 08-26-2013, 09:52 AM
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Yea, I was curious about the bracket on the firewall/wheel well. I've not looked into it much. I guess 315's would be out of the question on an RX8. Based on local results from Marc's car, i'm not sure it would benefit much from bigger tires anyway. The car is damn fast and very competitive with our flock of national level drivers up in New England.
Old 08-26-2013, 07:56 PM
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The issue beyond the 295 size becomes the diameter vs width which both then start to really impact clearance. Hoosier A6 sizes @ published OD x Section Width x Weight (Tirerack price 9-13-13):

225/40-17 @ 23.8" x 9.8" x 20 lbs ($270)
245/40-17 @ 24.5" x 10.0" x 21 lbs ($288)
275/35-17 @ 24.7" x 11.0" x 23 lbs ($310)
275/40-17 @ 25.5" x 11.0" x 24 lbs ($318)
295/35-17 @ 25.3" x 11.6" x 24 lbs ($340)
315/35-17 @ 25.6" x 12.6" x 27 lbs ($357)

225/40-18 @ 24.8" x 9.5" x 20 lbs ($341)
245/35-18 @ 24.7" x 9.8" x 21 lbs ($341)
255/35-18 @ 24.8" x 10.8" x 22 lbs ($341)
275/35-18 @ 25.5" x 10.7" x 23 lbs ($341)
285/30-18 @ 24.9" x 11.5" x 24 lbs ($357)
295/30-18 @ 25.3" x 11.6" x 24 lbs ($365)
315/30-18 @ 25.6" x 12.7" x 27 lbs ($376)

IMO an RX8 fully trimmed down to the minimum SP weight allowances won't need to go there. At that weight a 315 will need 11.5"+ width wheels to keep the tread-face flat, which would require cutting & flaring the fenders with steering limiters too.

The 275/35-17 on a 10 or 10.5" wide wheel looks the best to me, 17" wheels that clear aftermarket brake calipers with the proper offset are hard to come by and/or expensive. That said, a few people are claiming the car can be just as fast and better balanced in overall conditions running smaller width tires. So I added those to the list and may experiment with them on my STX wheels


.

Last edited by TeamRX8; 09-12-2013 at 11:51 PM. Reason: found a few dimension errors, added some other sizes, & added pricing info
Old 09-04-2013, 07:27 PM
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Congratulations are in order for Zelse's BHR-sponsored RX8 finishing DSP in 4th place at the 2013 SCCA Solo National Championships!



most awesome indeed against such a tough field of competitors
Old 09-04-2013, 11:04 PM
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Congrats, Zelse!
Old 09-10-2013, 08:31 AM
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Didn't even know this thread existed until just now! Firstly, thanks to Team for the props, much appreciated! I admit, I drove like complete poopydoodle. I watch the videos and I was late on everything, and got lost twice on the East Course somehow. I wasn't used to the pressure/excitement/everything that is Nationals since this was my first..But that will definitely change next year.

But like Team said, it's in the car, thus why it placed 4th. Without Bryan Heikotter (the other alien), it would've been 3rd against the normal DSP contenders. I'm pretty proud of that considering she's still not at 100%. The big remaining things that are getting taken care of is aero from Joefis Racing (just dropped the car off on the way home from Nats), and my long tube header I've been working with BHR on for the past... well..Long time now. Then this winter, BHR and I will be rebuilding the engine for high compression (right now the front is mid 9's and the rear rotor is high 7's) and port matched per the rules. I'll take a bunch of pictures too so no one can try and say I have illegal crap done on the car, you know?

To contribute to what Team had mentioned about wheel fitment, I showed him at Nats how the pinch weld in the front wheel well would get in the way (it also sits behind the wheel hub, so you can't do anything about it either, so fender flaring wouldn't help at all). To fit my 285's on my 18x10 +38, I need to run low caster, or else it will rub, so I run 3.5 degrees of caster (which I prefer anyways). Like Team mentioned, you can fit a 295, but would need different offset wheels and may need to play with your caster a bit. Anything more than that though, good luck fitting. I know you can do steering limiters but I'm not sure I'd like to limit the amount of steering I have... But that's just me!
Old 09-11-2013, 12:47 AM
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Zelse is definitely setting the bar for the RX-8 in Street Prepared. I have been running low caster for forever, so this along with the higher offset wheels is likely why the 295s went on OK for me (pic below, 10.5" +43 wheels). My only issue with them was rubbing the front outer fender lip some, which at the time I had the car extremely lowered and I didn't need/want to roll/flair it while running in the STX class. I did roll the rear fender lips flat for the fitment though. It's much easier to do than the front with no liner & rivet clips to deal with. It was just a test fitment at that time and a tight fit for sure.





It was definitely nice to finally meet up with Ray. I'd like to publicly apologize for my contribution to the various misunderstandings we've had over the last few years. It's good to know all this is in the past now and we can go forward as RX8 brothers in arms.


.

Last edited by TeamRX8; 09-11-2013 at 12:56 AM.
Old 09-11-2013, 07:45 AM
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First of all, congrats to Zelse and co-driver for a solid showing at Nationals! Your results are pushing me to join up in DSP for next year too.

As another data point, I put 285/30/18 BFG's on my car with the same 18x10+38 RPF1's. The BFG's have a little bit more tread with than either the 285 or 295 A6. I rolled the rear fender lips and there doesn't seem to be any kind of clearance issue back there at all. I didn't do anything in the front because the tire hits plastic that I can't move before it hits anything else. I also get some rubbing up against the firewall and it's rubbed through the front of the wheel well liner where it connects to the bumper. I only notice rubbing while driving around paddock with very high steer angles. This is what it looked like when I checked it with the front springs removed:

Old 09-12-2013, 11:37 AM
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Old 09-18-2013, 03:51 PM
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Well, I get to pick her up on Saturday to see the new aero! From what I can tell from the pictures, Joe over at Joefis did an amazing job! Can't wait to see it in person and see the painted final version. I just did a blog post about the work and some of the pictures he's sent, so check it on out.

RE-Zelse: New Aero From Joefis Racing

Since I've gotten this done, this means he has a template handy now and can make these easily and send them out.
Old 09-18-2013, 04:46 PM
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Originally Posted by Zelse
I'll take a bunch of pictures too so no one can try and say I have illegal crap done on the car, you know?
Originally Posted by Zelse
These pieces are 100% by the book, and totally class legal
I hope this obsession doesn't have to do with our discussions the things I pointed out to you were clearly honest misinterpretations of the rules. They were only brought up to help you avoid having a problem, not to accuse you of anything.

just so everyone is clear, because it seems like several aren't despite it being discussed extensively on the forum; you can't remove the plastic shroud off the front crash bar to route a CAI, Racing Beat ram duct, etc. This is very specifically detailed in Appendix F - Clarifications - Street Prepared. The clarification example there is for the MX5 Miata, but it also applies to anything similar and in the case of the RX8 is exactly the same thing.

It would also be wise for any serious National competitor to fully read the first introductory page of Appendix F, particularly with regard to rules interpretations. Removing the cloth insulators from the engine bay, as ragged and as ugly as they may be, and trying to claim they are allowed to be removed as "exhaust shields" under 15.10.I is the kind of thing they are referring to there. IMO your hood liner isn't an exhaust shield and neither are they. Just like in the case of the plastic piece on the MX5 & RX8 being called a "radiator shroud" by the manufacturer in the parts literature, these components are not listed as exhaust heat shields there. Sort of the reverse yet same concept about how these may be judged.

In either case, or in many others, these are the "trivial for performance but critical WRT rules compliance" kind of things that can result in a high trophy position or Championship win instead turning into last place and you being bummed out for the next 6 months.


.

Last edited by TeamRX8; 09-18-2013 at 05:19 PM.
Old 09-19-2013, 12:18 AM
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I guess the obsession did stem from the discussion a bit. Not negatively towards you or anything at all, but mostly out of fear in the simple fact that...The last thing I would want to happen is to be protested by some punk at Nationals just because of a simple misunderstanding, you know?

As for the insulators, I don't think that would be an issue with anyone, especially the BMW guys. I thought you said you were going to take yours out anyways

As for the intake, I'll be purchasing the piece over winter and fixing all that, but I haven't decided yet what the best approach to this would be. I'm still considering writing a letter to the SEB arguing that this makes zero sense given what we can and cannot modify in this class. we'll see I suppose.
Old 09-19-2013, 01:56 AM
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I would rather remove mine if it was possible, it's just not allowed or worth it

sooner or later it will happen, be prepared to deal with it when it does
Old 09-19-2013, 09:55 AM
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The question is, do you think it would be one of us, or one of the non RX-8 DSP guys?

I was thinking about it last night too BTW. I've actually always been obsessed about being "by the book" because when I win, it feels 100 times better to also say, "And the car was legitimate" as opposed to,"Oh I had to do these shady things to make the car perform better".

When I win, I want it to be because of my skill and my car being 100% prepped by the book, not because I cut corners, you know? That's just my two cents.

Anyways, enough about that. No comments on the aero man?? I was expecting to hear some input on it.
Old 09-19-2013, 01:14 PM
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Originally Posted by Zelse
The question is, do you think it would be one of us, or one of the non RX-8 DSP guys?
This is this the wrong angle to approach this from. Do you want to rely on what another competitor is not going to do for you to maintain your finishing position? What I'm trying to say is, wouldn't you rather be in charge of your own destiny?

BTW, if you want to convince me to come to DSP, bring the car down to NJ for an event and let me co-drive.
Old 09-19-2013, 02:59 PM
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Considering you're the final straw of why I stuck with the whole RX-8 shenanigans, I'd totally be down for that. I'll definitely be doing more NJ events next year too.

As for the rule stuff, you're right. So I'm doing the craziness... My approach is that I'm writing to Mazdaspeed for advice on a way to get a tech bulletin out that specifically says that piece is apart of the emissions system, or, apart of the intake system. If I can get that, then we're home free. If not, I'll have to try a different approach to the board. Their stand point is that they don't want people to modify body trim pieces to fit intercoolers and what not, so they see this in the same light.

As for the insulation, I'm just going to straight up write to the board and ask for a clarification on the RX-8 in SP regarding this. They weigh nothing, they act as both heat insulation and as sound deadening, and are held in by plastic nuts. They also are featured on next to no other car (hood insulation aside), and there is no rule in any class (I looked multiple times) that specifically says you can modify/remove/etc. to engine bay insulation... So that would mean that even in a crazy class like XP, you would still have to run engine bay insulation, which is just straight up silly. I know in Street Mod you can remove hood insulation because it is seen as part of the hood, but there is no mention of engine bay insulation.
Old 09-19-2013, 06:53 PM
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again, I'm just sharing what I think I know. That said, I'm not always right WRT how the SEB may view things i.e. the Toyo tire legality issue (I still think I'm right, they just didn't want to upset the ST/STS apple cart and PO a major supporter/sponsor). Over the last 5+ years I have been the Protest Chief at almost every Tour or Pro Solo event I attend, 7+ per year. Not always right, but been around the mulberry bush a time or two in the last 20 years of doing Solo. Reasonable people will disagree, which is why we have the process for handling such things.

Letters to/from Mazdaspeed mean nothing. They are the manufacturers racing arm. The rules define this relationship very clearly; official manufacturer non-racing data & documentation only. You won't get Mazda to go back and rename the part, but feel free to try. Even if you did the SEB still has the option of claiming they only did it for racing purposes and kill it anyway.

The factory literature doesn't classify engine bay insulators as an exhaust heat shield. It's not in the vicinity of the exhaust. It's called an insulator by Mazda. It's an engine bay heat shield against radiator/engine heat just like the hood liner. That's how I see it. If you can convince someone to let it be removed I'll be happy. I couldn't keep the rubber strips on under the rocker panels and tried to get them clarified as removable under the ST rule for removing rub strips, mud flaps, etc. They said no. The strips cost over $100 each new I lost a few at events when they fell off, it sucks. Same thing, no real weight or performance advantage. They said they have to be there. Oh well.
Old 09-19-2013, 07:53 PM
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Originally Posted by Zelse
Considering you're the final straw of why I stuck with the whole RX-8 shenanigans, I'd totally be down for that. I'll definitely be doing more NJ events next year too.
I'm always flattered when you say that. Meeting kind people like you is one of the reasons I enjoy this sport so much.

More importantly, checked out the pics on the blog of the splitter and spoiler, got to love the work they do. Can't wait to see it completed.
Old 09-19-2013, 10:39 PM
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^maybe he'll listen to your sweet talking ways and reinstall those insulator panels in the engine bay

I was thinking about using 1/4" birch plywood for my splitter and spoiler, then laquering it up all glossy like high grade furniture along with a ChrisCraft logo ...

Last edited by TeamRX8; 09-19-2013 at 10:42 PM.
Old 09-20-2013, 05:58 PM
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so the big question is, what does the splitter and spoiler weigh total?

Guessing at least 20 lbs myself
Old 09-20-2013, 07:48 PM
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Also Rota recently released their RT5 wheel in a 17x10 +50 5x114.3 size

weight is on the fugly side at 20# each but they are really cheap, a new set is FS on eBay for $800

Rota Wheel RT5 New Style RT 5 17x10 5x114 3 50 White S2000 MR2 Prelude | eBay
Old 09-22-2013, 06:47 AM
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can't tell you how happy it makes me to have finally pulled out the AC system again

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