Care to share how much you limited the steering by? Based on what I was looking at last night with a slightly narrower wheel (10.5”) and tire (295), it seems like it might be quite a bit with 11”/315 even with the pinch weld removed from the back of the wheel well.

WRT your question on brake weight reduction from OE, making some assumptions I came up with 46 lbs total lighter than factory parts; 14 lbs/front corner and 9 lbs/rear corner

 

Thanks Mark.

I think I'm dense because I can't figure out from your posts exactly how to put together the brake kit you have. I'll study more.

My steering rack spacers were on the order of 15mm thick and I have no issues with rubbing anywhere. I can drive around paddock at full lock with no problems. Wheels are +38, 18x11 with 315 tire.

 

I have the RacingBrake #2015 stock size front brake kit which has changed in that they only offer the wider 25mm disc now:

https://www.rx8club.com/series-i-whe...ecials-218708/

however I was assuming 5.0 lbs/front caliper in estimating the weight savings in the prior reply. In the link above it states 4.5 lbs each. I bought my kit in late 2009 and upgraded to those calipers with the SS pistons in 2012.

To duplicate what I now have you’d want to buy this caliper upgrade kit (no rotors)

https://www.racingbrake.com/Upgraded...8-p/2023-k.htm

Then build a pair of 2-pc rotors 12” OD x 0.95” thick, then have 5/16” and center clearancing shaved off the bracket along with additional drilling and tapping of the two M12-1.25 caliper mounting holes the same 5/16” to drop the caliper down to the smaller OD rotor. It’s a bit involved because I’m limited to factory RX8 sizing and I already had the kit; buying oversized/thicker rotors and having them machined down, along with the hats and machining them to the proper rotor positioning and center hole dia.

For SM you don’t have those limitations. So an NC Miata kit that uses a standard 11.75 x 0.81 or 1.0 rotor is probably going to make more sense for effort and cost, plus be lighter still. V8Roadster offers several kits with either Wilwood or Stoptech calipers. Also several 12.19” rotor kits if you’re hesitant to go that small.

 

 

It's been a challenge due to work being super busy this time of year (end of the fiscal year is always crazy) but I got some stuff done on the car.

Converted the fuel rail to a dead-head setup.



Installed and plumbed and wired the surge tank



Made a quick and dirty heat shield for the turbo and manifold. The ECU temperature had been getting pretty hot so the goal here is just to reflect the heat back and away from the front of the engine bay.

 

The event this past weekend went pretty well. I had the tank down around 1/4 full and didn't have any fuel starvation problems at all. Looking at the logs after the event, the fueling was really consistent, no drops in fuel pressure and no issues running lean. Sam Strano drove with me and we pretty much matched each other run for run in the car. He ended up getting me by 0.15 after four runs.

I'm not super happy with the handling. The balance is good and it's quick to turn in but it just feels "bouncy." It's not that stiff as far as RX-8s go, but looking at it on course, it looks soft. It looks to me like it spends a lot of time on the bump stops in the shocks, or there is something binding up and releasing. In Oscoda it was magical, so I'm hesitant to really make any changes. DC is a weird lot, extremely bumpy and this course went over the worst of them. More bump damping helped, as did removing some rebound, and I think it will be OK on concrete at Nationals, but it still needs sorting.

As far as the "official" results go, I was 2nd on index, about 0.01 behind Tommy Layton in his FS M3. Tommy is always fast, so I think that's a good sign.

It's also burning a lot of oil on throttle lift. It doesn't seem to burn any on throttle, so I'm not sure what's going on. I don't see anything on the plugs to indicate it's burning oil. I wonder if it's a PCV thing since it's done that since the very first event.


Overall, I guess I'm happy, but it's really nowhere near the top cars in the class yet. Lots of work to do next season.

 

It might be too low. I think that’s a common mistake I’ve been guilty of myself.

It might not be stiff enough either. Which having to add bump and soften rebound might suggest as well. You have a fairly serious splitter and wing installed. Technically you should be running higher spring rates than anyone else on here. Which I think you’re below what I have planned for my DSP build.

you’ll probably need to seek input from other Mazda sources on the off-throttle oil consumption since most of us have little/no experience with your transplanted 2.5L MZR engine.

 

It could very well be too soft. I don't think it's too low, but it could be too low for the spring rate.

Yeah, I don't expect any help on the oil burning thing, I'm just using this thread as a way to document progress.

 

Combined with the aero and bumps, too soft seems most likely.

 

I did end up disassembling a front corner again because I forgot to weigh everything previously for determining an accurate unsprung weight value for my car. The modified front brakes in entirety; RB caliper, brake pads, modified mounting bracket, Wilwood front rotor assembly, and all hardware came to 19.1 lbs total per corner. The stock calipers with pads and mount along with front rotor is 31.5 lbs according to the Stock Parts Weight thread, but I think there might be a bit more weight for the steel mounting bolts that are fairly chunky. So maybe round it off to 32 lbs.

so approx. 12.9 lbs/corner savings is the accurate number, just a bit under the 14lbs/corner I had estimated previously. That assumes the OE weights listed in the other thread are accurate since I don’t have those parts to verify in full.
.

 

i had oil blow by the turbo seal on my Evo during off throttle after high boost when the turbo seal was going out.

 

It's a new turbo so I'm hoping it's not that. It was suggested to me that EFR turbos come with an oil restrictor which is often not restrictive enough, which can cause this.

John

 

i ran a smaller inline restrictor when i had ball bearing turbo

 

If oil pressure exceeds 5 bar it needs additional restriction. Some company in Germany sells one that BW engineers recommend.

 

Definitely higher than 5bar per my ECU logs

Looks like Turbosmart sells a 40psi regulator which is suggested to be used in systems that exceed 5bar. looks like another upgrade for post-nationals.

 

the spending never ends ...

A regulator would be ideal imo. The issue with a restrictor is that it varies with pressure.
.

 

Congrat’s on finishing 2nd in S1 for the Pro Solo Finale
.

 

S1, but yes, thanks Mark. I'm happy with the result, but I'm way off the pace of where SM should be. Randall had the raw time to beat me but coned it. But, that's the nature of this hobby.

Fighting a steady state push. I think the car is too low up front for the spring rate. I may raise it up 10mm and also take some front bar out of it. Given I have no expectation of being competitive at nats, I may as well try some things.

Rachel drive the car on the test course and seems happy with it in general. I'm excited to drive both courses... They look super fun.

 

Sitting in 4th place less than 1/2 sec out of first and 1/4 sec out of 2nd with the next driver behind you down 3/4 sec after Day 1 at Nationals; not too shabby

 

Yeah, except all of SM is way off the pace.

And I blew the motor.

 

Well dang, am so sorry to hear that. Any idea what happened?

 

Leakdown was bad before the finale. Probably cracked a ring. It got more and more blow by during the pro and started blowing oil into the catch cans... Then it spun a bearing.

I think lots of running lean and over boost stuff... All my fault

 

yikes, sorry to hear that.

 

Sounds kinda similar to mine in certain turns, especially tight (for racetrack anyway) steady relatively long turns. Like it doesn’t want to take a set right away. Feels more lateral though not vertical but I could be wrong. I’ve been blaming it on the stock rear suspension bushings but you’ve already got sphericals. Mine improved going from 180k mile original bushings to new stock one but still it’s limiting especially as it delays getting to the power. Will be interested what you find to be the cause.