The Official "RX8 in DSP" Thread - Page 2 - RX8Club.com

Go Back  RX8Club.com > RX-8 Competition > RX-8 Racing
Reload this Page >

The Official "RX8 in DSP" Thread

Notices
RX-8 Racing Want to discuss autocrossing, road-racing and drag racing the RX-8? Bring it here. This is NOT a kills/street racing forum.

The Official "RX8 in DSP" Thread

Old 09-23-2013, 10:25 AM
  #26  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
Waiting for a nice day to take some pictures, so possibly today, but goddamn these pieces are gorgeous. 15 lbs. total for both front and rear.
Zelse is offline  
Old 09-23-2013, 12:59 PM
  #27  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
^^not too bad for aluminum sheet metal

started pulling the stereo components out last night, also removed the steering wheel/air bag assembly

a bit discouraging that everything from the factory is already near minimum weight :-/
TeamRX8 is offline  
Old 09-23-2013, 01:25 PM
  #28  
Angler of the Year
iTrader: (3)
 
slvrstreak's Avatar
 
Join Date: Dec 2009
Location: George-uhh
Posts: 1,556
Thanks: 0
Thanked 0 Times in 0 Posts
I would recommend Reynobond, Alumalite, etc for the splitter
lighter, stiffer, more durable but, will buckle before your bumper does (which is a good thing)
slvrstreak is offline  
Old 09-23-2013, 01:28 PM
  #29  
Angler of the Year
iTrader: (3)
 
slvrstreak's Avatar
 
Join Date: Dec 2009
Location: George-uhh
Posts: 1,556
Thanks: 0
Thanked 0 Times in 0 Posts
I do have a question though
why the fascination with such large tires?
is it just a better setup for autoX?
do you really need that much tire or even have the power to push that much rubber NA?


edit: that was 3 questions
slvrstreak is offline  
Old 09-23-2013, 01:32 PM
  #30  
Angler of the Year
iTrader: (3)
 
slvrstreak's Avatar
 
Join Date: Dec 2009
Location: George-uhh
Posts: 1,556
Thanks: 0
Thanked 0 Times in 0 Posts
nice job on the aero
how does the splitter connect to the car/chassis and is it adjustable?
slvrstreak is offline  
Old 09-23-2013, 02:05 PM
  #31  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
I'll let Mark answer the tire question as he can probably articulate it better than I. I will add however that I do believe there is a tire/wheel limit that is opitimal per car/chassis/power/torque and what seems to work really well is 255 on an 18x9 wheel and a 285 sized tire on a 18x10 wheel. Heat generation on the tire and outside temperature also plays a roll in this as well.

With the front splitter, I'll get more in-depth pictures soon but if you look at their FB page it has the whole build process and setup of it. It's non-adjustable however. Per the class rules we're limited with what we can do anyways.
Zelse is offline  
Old 09-23-2013, 10:07 PM
  #32  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
For the record, I weighed the pieces in. The rear spoiler is only 6.6 lbs. and the front is 7.4 lbs. So an exact total of 14 lbs! That's pretty good.
Zelse is offline  
Old 09-24-2013, 06:03 AM
  #33  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
Autox is much more transitionally intense (or violent in some respects) than road racing. Despite the higher speeds and longer duration loads, for track things happen in much smoother and slower timing. That said, there's a point the weight and diameter starts to work against the chassis/engine so it can come down to available wheel and tire choices. I have a good set of 17x9 wheels that I'll try at least 245/40-17 (225/40-17 seems like a stretch) and I'm working on a set of 17x 10.5 wheels to also try the 275/35-17. Despite also having 18" wheels I prefer to focus on using 17" to start.
TeamRX8 is offline  
Old 09-24-2013, 04:14 PM
  #34  
Registered
 
Join Date: Feb 2012
Location: Youngstown, OH
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Howdy,

Originally Posted by TeamRX8 View Post
Autox is much more transitionally intense (or violent in some respects) than road racing. Despite the higher speeds and longer duration loads, for track things happen in much smoother and slower timing. That said, there's a point the weight and diameter starts to work against the chassis/engine so it can come down to available wheel and tire choices. I have a good set of 17x9 wheels that I'll try at least 245/40-17 (225/40-17 seems like a stretch) and I'm working on a set of 17x 10.5 wheels to also try the 275/35-17. Despite also having 18" wheels I prefer to focus on using 17" to start.
How come? Do you want the slightly shorter diameter as opposed to the 285/30-18? Or more sidewall?

Mark
marka is offline  
Old 09-25-2013, 07:07 AM
  #35  
Angler of the Year
iTrader: (3)
 
slvrstreak's Avatar
 
Join Date: Dec 2009
Location: George-uhh
Posts: 1,556
Thanks: 0
Thanked 0 Times in 0 Posts
makes sense...thanks for the explanation guys

marka - lighter, cheaper tires, slightly shorter (more grunt out of the corners)
slvrstreak is offline  
Old 09-27-2013, 01:12 AM
  #36  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
if I'm not mistaken the winning DSP car this year was using 275/35-17 ...
TeamRX8 is offline  
Old 09-27-2013, 08:51 AM
  #37  
Registered
 
Join Date: Feb 2012
Location: Youngstown, OH
Posts: 69
Thanks: 0
Thanked 0 Times in 0 Posts
Howdy,

Originally Posted by TeamRX8 View Post
if I'm not mistaken the winning DSP car this year was using 275/35-17 ...
Mostly I'm curious because I've literally never heard of an autox car on A6's going slower with wider tires.

The winning DSP car this year didn't win because of superior car prep. :-)

Mark
marka is offline  
Old 09-27-2013, 09:12 AM
  #38  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
There are a lot of factors involved, but were obviously good enough to win by a substantial margin regardless. Having the widest tires is no guarantee of anything, assuming they are actually wider where it counts or in actual use given the application parameters, like a sub-11" wheel on a 2600# car
TeamRX8 is offline  
Old 09-27-2013, 03:21 PM
  #39  
Registered
 
Join Date: Mar 2012
Location: Long Island
Posts: 81
Thanks: 0
Thanked 0 Times in 0 Posts
Looking forward to seeing more RX-8's in DSP next year. After some further thought I'm confident the car will have a chance. Marc's car has shown great potential. It will take $$'s I don't have though to build my car further. If only the budget allowed I would be for sure.

Running the widest wheels possible that do not extend outside the body is a good start. If pursuing the 275 route, a 275/35-15 could potentially fit in the rear. It would eliminate the need for a final drive change and possibly allow the rear to work better by not screwing the roll center as much.
JeffH is offline  
Old 09-27-2013, 06:05 PM
  #40  
Registered
 
Join Date: Mar 2012
Location: Long Island
Posts: 81
Thanks: 0
Thanked 0 Times in 0 Posts
An informative post by Team on wheel fitments:


Originally Posted by TeamRX8 View Post
A 10" wide wheel is the max width you can use that sticks close to the factory offset and takes advantage of all the inboard wheel space @ 50 - 52mm offset. With a fat tire (285 or 295) it will fill out the fender and also look mean as hell with all that rubber under there. You also aren't going to experience handling and driveability issues that result from wheel offsets lower than factory.

If you want to run wider than 10" then you have no choice but to start lowering the offset because there is no more inboard space available without extreme mods like tubbing and major suspension relocation/redesign. With every width increment above a 10" width @ +50-52mm offset you'd have to move the offset out by half that amount.

So for 1/2" increase above 10" width (10.5") half that amount is 1/4" = 6.3mm or 7mm for practical purposes. At each 1.5" increase you could subtract 1mm to account for the fractions adding up to a whole number, but there aren't too many RX8s using 11.5" wide wheels let alone 13" wide, lol. At anything past 10.5" wide using this basis the fender will need pulling or flaring for an equally wide tire not to rub because it will be sticking too far outboard of the factory fender lip to clear. So the resulting size/offsets would be:

10.0" @ +50 to +52mm
10.5" @ +43 to +45mm
11.0" @ +36 to +38mm
11.5" @ +30 to +32mm
12.0" @ +23 to +25mm

Otherwise running undersize tires to accomplish this fails on several accounts. To make the tire sidewall lean for fender clearance means that it has to lean both on the inside and the outside. A ridiculously narrow tire is required the further outboard the wheel lip sits outside the fender lip. Way back when tire sidewalls lacked good support but todays performance tires are designed such that a wheel wider than the tread width/contact patch width accomplishes no performance benefit. So a wide wheel with a high positive offset just to put a skiny tire on it is pointless and silly. Some wheel width/tire size reference points are:

9" wheel @ 245 to 255 tire
10" wheel @ 275/285 tire
11" wheel @ 305/315 tire
12" wheel @ 335 tire

Some change in offset from the original +50mm (S1 models) is not going to have much impact, but as you continue to push it out the resulting scrub radius moment arm is creating a force that makes the tires want to turn out, putting the steering components in constant tension while driving in a straight line. As such a setup encounters uneven pavement, bumps, water puddles etc. that moment arm is going to try and rip the steering wheel out of your hand position. Even moreso for these conditions under braking because this same scrub radius moment arm is going to magnify the braking deceleration forces against the steering wheel as well.
https://www.rx8club.com/series-i-whe...9/#post4150593
JeffH is offline  
Old 09-27-2013, 11:56 PM
  #41  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
lol, i forget posting things like this ...

Wish I could find a set if 17x10.5 +45 SSR Type C or C-RS wheels @ 17.2# each. Supposedly they made at least one run production along the way, but I've yet to ever see a 2nd hand set up for sale ever ....
TeamRX8 is offline  
Old 10-08-2013, 11:22 AM
  #42  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
A little late on the post, but I finally did a nice digest of my thoughts on the aero.. When I was dealing with a dying fuel pump! Check out the post and feel free to leave comments or post your thoughts on here.

RE-Zelse: Aero Testing @ Renegade

The overall verdict? Get it. With some minor alignment changes, I know that it will make the car pretty unstoppable. I was able to carry a lot more speed into various elements, flat foot slaloms for the most part, and get on the throttle a lot earlier. I had to brake earlier now however, because of the push it creates, but it's a very different type of push than say.. A car pushing because of alignment settings. You can feel the difference too.

Anyways, thats my two cents!
Zelse is offline  
Old 10-09-2013, 11:08 AM
  #43  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
sounds like fun, so thanks for rubbing it in while my car is sitting in a thousand pieces ...
TeamRX8 is offline  
Old 10-10-2013, 02:52 PM
  #44  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
:P Your car will be whole again soon though. Take some pics of it in pieces! Tell us what you're working on! Stop being a shadowy figure in the dark and share some goodies.
Zelse is offline  
Old 10-10-2013, 03:00 PM
  #45  
Angler of the Year
iTrader: (3)
 
slvrstreak's Avatar
 
Join Date: Dec 2009
Location: George-uhh
Posts: 1,556
Thanks: 0
Thanked 0 Times in 0 Posts
+1 on that!
slvrstreak is offline  
Old 10-10-2013, 08:27 PM
  #46  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
well I already have a number of items from STX prep, but the things done so far

audio system out
steering wheel & air bag out
AC system out
most emissions components out
radiator/fan/shroud assy out
interior torn apart
front bumper cover and undertray are off

next thing on the list is pulling the engine/trans, but have to help member WBTRotary! install his Daryl Drummond built engine starting this weekend before getting to this step

a bunch of stuff on order, don't really care to go into it all for now, but pretty much in keeping with my usual thought process & prep level


.

Last edited by TeamRX8; 10-11-2013 at 04:47 AM.
TeamRX8 is offline  
Old 10-18-2013, 03:14 AM
  #47  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
couple of things rolling in,

ULW steering wheel with Miatacage.com splined QD setup




mini clutch with Mazdatrix flywheel setup




sorry for being secret squirrel about the scale figures, just can't help myself


.
Attached Thumbnails The Official "RX8 in DSP" Thread-steeringa.jpg   The Official "RX8 in DSP" Thread-clutch-flywheela.jpg  
TeamRX8 is offline  
Old 10-18-2013, 07:05 PM
  #48  
Registered
 
etzilon's Avatar
 
Join Date: Oct 2011
Location: Houston, TX
Posts: 425
Thanks: 0
Thanked 1 Time in 1 Post
Originally Posted by TeamRX8 View Post
mini clutch with Mazdatrix flywheel setup
When I have good dreams, this combo is in them.

BTW, I hope you have a winch on your trailer!
etzilon is offline  
Old 10-18-2013, 09:15 PM
  #49  
Koi no Ousama
Thread Starter
iTrader: (25)
 
TeamRX8's Avatar
 
Join Date: Apr 2005
Posts: 20,551
Thanks: 0
Thanked 277 Times in 229 Posts
I have one planned, but it's my understanding that this is not as much of an issue as it is sometimes made out to be. There are a lot of different clutch suppliers out there, a wide array of materials, as well as the quality and expertise level of either. They're not all created equal, that's for sure. I suppose only time will tell though.

picked up a used S2 6 spd transmission today ...
TeamRX8 is offline  
Old 10-21-2013, 01:00 PM
  #50  
悪魔のR
iTrader: (12)
 
Zelse's Avatar
 
Join Date: Jan 2008
Location: Boston
Posts: 1,528
Thanks: 0
Thanked 0 Times in 0 Posts
Oooh decided to go with the S2 Tranny, hmmm? Doing the rear end as well or just the transmission? I've wondered what the car would be like with 4.44 but S2 tranny instead. Definitely would be a bit slower but able to stay in 2nd in the powerband no problem...
Zelse is offline  

Thread Tools
Search this Thread
Rate This Thread
Rate This Thread:
You have already rated this thread Rating: Thread Rating: 0 votes,  average.

Quick Reply: The Official "RX8 in DSP" Thread


Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2018 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.