It will work ok. Magnus has a thread here where he did the same thing by lengthening the primaries and using a steepish angle collector with a reducing cone outlet (I personally recommend a 12 or 15 deg merge with 3" straight outlet) and he seemed to have decent results

 

For your header, are were you designing 2" primaries? 1 7/8?

I likely jumped the gun too quickly, grabbing a ton of Burns stuff to get it all at the same time. For 1 3/4" primaries, they don't do a collector exit at 3", staying largest exit at 2 5/8", which we then stepped up to mate with the remainder of the system right away. If it was 2" primary, burns can collect at exit of 3".

I would guess i might as well re-do the collector right away...

 

2"OD 20 Ga. T321 is my intention for primaries, 18 Ga. for the merge collector. While B-S has brand-name recognition, not my personal preference. I'd recommend Pro Fabrication in NC or SPD Exhaust in CA.

https://www.profabrication.com/produ...ollectors.html

Merge Collectors

The issue may be that the RB header has the three 1.75" pipes so close together that there isn't much of a merge into 3", more like a straight dump or with a steeper merge angle there isn't much to work with. Not sure if it'd be worth changing after the fact though.

Again, Magnus did it that way so I'm not sure you'd be wrong to just stay the course that you're already on.


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I can always come back to Header 2.0.

 

So it turns out that the S2 radiator core dimensions are a bit different than the S1 radiator core. I knew it was 3/8" thicker, but was surprised to see that it was about 1/2" less side to side and a small amount more top to bottom. I updated the information in the first post of this thread. A custom 2-pass radiator should just barely squeeze in between the frame rails using the S2 dimensions, which it uses side end tanks rather than top/bottom end tanks like the OE radiator.

I also need to go back and update that page to the 2017 SP rules. A few things have changed since this thread was started.




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BTW, be advised that most of the aftermarket radiators I've seen don't meet minimum OE radiator core dimensions required in the Street Prepared rules.

 

RX8Perf Radiator dimensions I had been given 27" wide, 16" tall, 3" thick vs. OE of 25.5, 14.5, and 1. Though I should also just measure myself to be sure...

 

No, those are the overall dimensions for the RX8P radiator.

How to Measure Radiators

I was told that the actual core is 24" x 16", which leaves it short on side-side lengthper the current 2017 Section 15 SP allowances. I didn't ask about the thickness because it was known to be thicker than OE already. As stated in the rules the core must be equal to or greater than all three of the OE core dimensions. Which BTW you can't mix and match. Update/backdate allows you to choose either the S1 or S2 radiator/core dimensions only. It's a bit stupid of rule, as unfortunately many of them are, because it forces people to spend $$$ for custom parts without really accomplishing anything useful.

My intention for now is to use the S2 OEM radiator with a 14" 2-spd 1500/2100cfm pusher fan on one side in the front and a custom shroud in the engine bay. I believe this is about the lightest option to get the job sufficiently for the intended use.


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Fudge.

At least my current driver performance expectations are low. I'm not likely to want to miss Nats this year, and I'm fast running out of time to even get going. I might just have to do an upfront declaration with the class on my Radiator and accept the protest if it comes (for this year at least).

I'll still do a quick personal measure to have a look at it...

 

So I need new ring gear bolts, and I'm likely going to order both the 10 and the 10.2 to save time. I was supposed to take the ring gear off before shipping to Lugod, rushed through stuff and didn't do it. Need new ring gear bolts, and don't have them in hand to measure.

My searches are coming up with "you will need to measure to be sure" between the two sizes. Just curious at this point if anyone is certain which size an S2 4.77 ring gear takes?

 

So, how long is your car going to be at the Alan Au SpeedShop?
He grilled me about all sorts of things while running my car through tech inspection last weekend. You're definitely giving him a baptism by fire in all things RX-8.

 

Most people reuse them without issue, including me

Or maybe you didn't get them back? Not sure exactly what you meant.

 

bingo

 

Maybe send Kevin at Rotary Resurrection an email for some info. He sells some used units and takes a lot of them apart.

I purchased a used R&P from him for our XP RX7 and he was extremely helpful with info about backlash etc,

 

This may have been stupid human tricks. I've been told bolts should've come back, will have to dive into the box of peanuts again to see if I can find them when I get home.

EDIT: confirmed stupid human trick... Found bolts, everythings in and snug. Just need to torque everything (car's been up in the air forever), and do a basic toe check for Sunday. Real Alignment will have to wait...

Did you make any progress Mark? Do you think we'll see you at Nats?

 

We had our first national event outing with "Riley" this past weekend at the NJ Pro.


We got to meet Gigglhurtz here on the forum (can't wait to see you back out once you get suspension on that car!). Marc was also there, but unfortunately had an overheating issue. Fingers crossed his motor is okay, as he had to pack up and trailer the car home.

We are still finishing prep on her (still don't have a tune) but took a risk and added aero on Thursday night before the Pro. We didn't even decide to do aero until Monday, ordered parts Monday night, half the order got lost through UPS, and we still pulled it off by Thursday somehow. We anticipated the car to be pushy since the rear aero seems like it would do more than the front, so we added the rear bar back on. With a few more tweaks to dial out the pushiness, the car was amazing all weekend.

Ended up with the win in L1 and the Ladies Challenge (hello four Hoosiers plus a bunch of Mazda and SCCA money!!!) and 4th and 7th in open DSP (14 total entries). Jeff was about 9 tenths out of the lead, combined. Not bad considering we were losing about .4 per side to the launch advantage, and still don't have a tune on the car. The course was also a little power biased, with one big dig, which you can tell by looking at pax results. Although we couldn't quite overcome the power disadvantage, the Anze-Hurst suspension was working magic over the bumps on the course - can't say enough good things about the Penskes.


We did have some grinding issues when shifting to 2nd at high rpm. Going to start keeping an eye out for a replacement transmission - if anyone hears of any near CT please shoot me a message. That, or figure out how to replace the 2nd gear synchro. We are still running the S1 trans.


Overall, the car is a TON of fun. Can't wait to keep developing her. Next up is the Toledo Pro in a few weeks.

 

Well I have 5 bad S1 trans I can give you for parts, lol. 2nd gear teeth are stripped on most of them, but never had any synchro issues prior to that. I'll strap them on a pallet and you pay freight.

Congrats on the L1 and LC wins. That really makes for a super fun event and great life memories.

Still have a ways to go on my car. Didn't make it out there to do anything last weekend. The radiator fan just arrived and also finally found & received the proper carbon fiber tube I was looking for to make a custom MAF setup. Nats might be my only real hope this year besides any local events, just depends.


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Thanks! Great memories for sure!

So if we swap to an S2 trans, it fixes the bad synchro issue and we can run it to redline to shift to 2nd right? But then there's some issue with the clutch fork bending or something? I need to do some more research, since it hadn't been a priority until now.

I find it funny that your car won't be ready due to things we are running all stock and don't plan to swap out for awhile Stock radiator and fans, stock air box and MAF, stock headers. Your car sounds like it'll be a beast once you get it out. Hope to see you at nats!

 

I never had any problem shifting the S1 trans up to 10k; up or down, just hitting it hard on the 1-2 shift and stripping the 2nd gear teeth off the countershaft on Pro launches.

Most of the S2 issues are 3rd and up for track guys that use those gears a lot. It should fix my 2nd gear problems because the main-countershaft spacing is increased with larger dia/wider gears. Plus as a top-loader style it's much easier to work on.

I have a bunch of custom things I'd prefer to do once rather put a bunch of OE crap on then piece-meal it. It's easier to build it up from stripped and a bunch more work to do it the other way. I'd rather take my time than get overwhelmed and probably discouraged. I hit it hard for almost 20 years and got seriously burned out. It's time to relax and enjoy it, otherwise I'd just as soon quit altogether and do many other things instead. Still considering that some even ...

 

Ah, you're starting from a torn apart car. I can respect not wanting to do things twice, and just do it right from the beginning. We started with a CS car. Although, part of what keeps us motivated to work on Riley is getting to have a **** ton of fun in her on the weekends. You just need to drive a DSP Rx8 and then you'll have no problems staying focused

On the transmission, I heard that the late S1 models, maybe late 2006 and newer, had a revision that improved 2nd gear to get most of the way to an S2 trans. Does that sound right to you?

 

Not that I know of. 2nd gear on the S1 countershaft is so small that it has to be cast as an integral part of the c-shaft and machined in place. When it lets go it takes out the c-shaft and the mating main shaft gear. When you buy those parts you get the latest and greatest version of them. Plenty of them broke regardless of being OE or purchased and installed well after that date. Only sychro problem I ever had was 3rd gear once that would grind occasionally. When we pulled it apart that synchro ring had cracked clean through from ID to OD in one spot. The teeth were fine otherwise.

 

Well I should get out there this long weekend any way. We'll see what happens when I try to bake an OE upper intake manifold in the oven to it's elastic temperature and try to remold it some. Hopefully I won't burn the place down, no current S.O. to complain about the smell at least

That's my main hangup to finishing out the engine. Once I clear that hurdle the rest will go a lot faster.


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so that's the other radical idea (or at the least the radical part of the idea...)

 

I recently just did this to my rx8 by hitting a curb. Any ideas on what is broke and how much it will cost. I know that my brake fluid was leaking and i tried to drive down the street but started smoking near the rear driver side tire. Also I have a feeling my axle is broken.

 

"one of the other", lol