carmudgeons.com  

Go Back   carmudgeons.com > Automotive Forums > Going Faster

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 01-07-2018, 12:20 PM   #1
John V
No more BMWs
 
John V's Avatar
 
Join Date: Apr 2005
Carmudgeonly Ride: Ram, MS3, CX-5, RX-8
Location: Glenwood, MD
Posts: 14,753
What the Mazda RX-8 should have been (new autocross car build)

I'm not 100% sure where this is going to go yet, but for the two or three of you that are interested I'll take a crack at documenting the work to get this thing together.

First of all, I have an irrational love of the rotary engine. I blame Car and Driver. In 1992, they broke the story of the upcoming FD-chassis 3rd gen RX-7, and by all appearances that was going to be a landmark car both for Mazda and for sports car enthusiasts. Given that I was 14 when that magazine landed in my mailbox, I had nary a hope of getting into a third gen anytime soon. But that article also had a little blurb on the second-gen RX-7 and while I had seen these cars on the road I knew next to nothing about them (okay, I knew next to nothing about cars beyond 0-60 times, skidpad g's and braking distances). When I landed a second gen turbo as my first car two years later, I was immediately a member of the Wankel-engine fanclub. That car taught me more than I ever expected about the love and frustration of working on cars.

Fast forward to 2004 and our very own Clyde offered me a ride in his first-year RX-8 at a local autocross. I had actually intended on buying the RX-8 when I got my first real job out of school in 2002, but delay after delay meant I had to postpone that goal, and I took the opportunity to buy one of my other high school dream cars, an E36 M3. I loved the M3, and to be honest my interest in the RX-8 had long-since waned, after the "scandal" of Mazda over-rating the RX-8's naturally aspirated rotary hit the press.

But hopping into that car was a revelation. It turns! It stops! It'll even do both at the same time! The wonders of a low center of gravity, the stiffest chassis on the market, double wishbones with great geometry. I was pretty torn. Clyde and I drove that car together for a few years and I've never forgotten the fun we had. I also never forgot just how phenomenal the chassis was and just how underwhelming the engine was.

I couldn't quite shake the thought of getting one as a street car and putting a real engine in it. LS V8? Seems like a great idea on paper, but it's been done and I'm not sure the character of the engine fits the car. Maybe something that revs a bit faster and puts a little less weight on the nose (mostly it's the weight of the beefy transmission that needs to go behind an LS, but either way it's weight). I had also thought for years about doing an autocross car using an RX-8 as a starting platform. There is one class that seemed to make perfect sense: Street Modified.

For those not familiar with SCCA Solo classing (basically everyone on the planet?) Street Modified is a class for four seat cars where the drivetrain is essentially free. The class was based around one rule: Make as much power as you want, using an engine made by the manufacturer of the chassis. i.e., Mazda power in a Mazda. The rule set obviously consists of more than that, but that's the basic premise. So my first thought two or three years ago was why not drop in a 3rd-gen RX-7 13B? The formula for making (relatively) reliable power (in the 450hp range is generally understood to be required for competitiveness) is known using the 13B-REW. There are kits to get the engine to bolt up to the RX-8 and it would be relatively straightforward to build.

But I got to reading the rulebook and was reminded that in SM, there is a minimum competition weight that is based on drive configuration, induction type and engine type. Long story short, a 13B turbo rotary has to weigh at least 2,700lbs. The same car with a 2.5L four cylinder turbo piston engine can weigh 120lbs less. On top of that, 13B-REW parts are pretty expensive and reliable tuning on a rotary is challenging. My mind was made up. I went hunting for an RX-8.
John V is offline   Reply With Quote
 

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 09:43 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Forums © 2003-2008, 'Mudgeon Enterprises - Site hosting by AYN & Associates, LLC