Or, "in my honest opinion"

 

"in my hokey opinion" is typically more accurate

 

"IMHO" Idiot must have opinion.


Not aimed at anyone in particular.




Unless the shoe fits.

 

Hey Dave, whats next on the list?

 

Just picked up the Nov issue (must have come in yesterday). I can't diagnose it, but the dyno indicates a problem. Your hp should peak around 8200 and it is peaking at 7200. There are various valves that are supposed to open ip and maybe the last one isn't opening. (the dip in the 6000 rpm range is related to extra intake ports opening - causes a dip first but then lets it breathe more.

 

Yup, there's definitely a problem. I thought it was tired old ignition coils, spark plugs and wires, but as you'll see in the next issue we've addressed that with some BHR products and although we do gain some peak hp and tq the early drop off in power is still there. So now I'm on to testing the three stage intake and checking for vacuum leaks. I'm also going to swap in a motorsports catalytic converter next week so perhaps that'll do the trick. Normally with a plugged cat I'd expect to see power loss across the board, which doesn't seem to be the case here, but it's worth a shot. Also have a Cobb AP that I'm going to plug in to see if we can see a lean condition or anything else unusual happening above 7k rpm. Perhaps an injector is misfiring or the knock sensor is pulling timing. It's still a mystery at this point, but we'll figure it out soon (I hope).

Sandman, in the Dec issue we upgrade the fuel pump, clutch pedal and ignition system courtesy of BHR, and then in the Jan issue we upgrade to a RB header, resonated midpipe with HJS cat. After that we'll tune the ECU with the Cobb AP, hopefully with Jeff from MM working his magic remotely. Then comes some racing buckets and a roll bar along with some swaybar testing and tuning. I also plan to do a wheel size test in the spring, using 17x10'' Enkei RPF1's with 255 RE-11s vs my current 18x10 Volks with 265 RE-11s. I may also upgrade to Moton Clubsports, since I'm having a tough time working around the limited rear shock travel with the BC coilovers. I also need to address the 4th gear engagement problem at high rpm (not a problem for Solo 2, but a big issue at the race track), so you'll likely see a story on refreshing the trans. Oh, and I've got some pretty trick aero stuff in the works too, though it remains to be seen if the rear wing will be STX legal next year (apparently there's discussion of making rear wings illegal for ST classes, but I haven't followed this too closely so I'm not too sure what the current status is on this). If not, I'll just run the aero bits on the car for Time Attack events. So far I've used the car more for Time Attack than Solo 2, so who knows, maybe we'll take the build in a new direction. Time will tell. I smell a supercharger in this car's future, but probably not until after the Solo Nats next year.

 

Cool, Modified mag needs to do an rx-8 edition release, with all rx-8 tech, and rx-8 showcases

 

Yeah, we gotta do something to pump up the attention on the RX-8. I want Mazda to keep on building them and the aftermarket/used part market to keep rolling. it is sad AccessPort dropped us. At least Mazda is supporting racing.

FWIW on track days I am going catless and then putting my cat back in for street. I don't the cat holding all that heat under my car at the track. I you are running on the stock tune, I doubt you are lean. The ap can read the stock wideband sensor, so you can check your AFR. Stock is about 11 to 1 at WOT. If I had a turbo, that'd be nice!

 

Can you post the dyno for after you changed the coils please - might help with diagnoses ....

 

Dave,

So now that you've had a good amount of time with the BC Racing coilovers. How do you personally like them overall?

I'm in the market for Coilovers, and I'm considering these. But if you had a chance to change to a different coilover setup, which would you choose and why?

 

might want to double check the STX rules.

 

since this is a "used" car buy, power may be down for a variety of reasons due to the previous owners lack of maintenance/ or abuse?
Compression/vac readings for example--i am sure yall know how to check out the rx8 engine lol.
One thing I found on mine was the fuel injectors were out of balance---to the point that one was actually leaking/dripping. You may want to check you injectors?
High rpm power lost is mostly due to as you have suspected--ignition based
changing the coils and plugs can sometimes give a car a 15 hp bump on the top end.
running premix at 1.5oz per gallon can also give you a slight bump up.

I dont know STX rules, but as far as transmissions --the 09 and later models have a much better box.
OD

 

You mean 1.5 ounces per gallon under special circumstances, like a track day? I run .5 per gallon on a regular basis and increase for track days. Dave, please note that when you go to the MM tune, that increases the amount of oil injected. That might mean you want to be more careful about how much premix to add to the tune.

 

A failing cat starts with power loss at high RPMs, which gradually evidences itself at lower and lower RPMs as time goes by.
As for fuel injectors benefitting from flow-balancing, I presented that data when I rebuilt my own engine and the OEM injectors can have flow variances as much as 10-15%.

 

Thanks for all the feedback, guys. I appreciate it.

Today I swapped on a RB header and resonated midpipe along with a HJS Motorsports cat (replacing the forward most resonator) and as you can see the top end is much improved but still flatter than it should be. Keep in mind when looking at this graph that the dyno I'm using is quite pessimistic compared to most. As I'm sure you all understand, it's the shape of the graph and the changes to its shape as modifications are made that's useful, rather than peak values. The dotted line is prior to the header and midpipe upgrades, meaning stock other than a MS intake and BHR ignition along with fresh spark plugs and 5w30 Q motor oil.



I briefly plugged in the AccessPORT to take a peek at the AFRs, ignition timing and injector duty cycle and everything looked good and normal there, but I'll post the data logs when I get a chance. I also checked the vacuum system and the 3-stage intake and everything appears to be in good shape there. I haven't had a proper compression test done though, so I guess that may be the next step. I've been holding off on that one since I don't want to pay the local stealership the $240 they want to charge me to bust out their fancy rotary compression tester.

NYC Drift King, I think the BC coilovers are a very suitable street setup. The ride quality with their off-the-shelf spring rates is really quite good and at 8/10th driving at the track they work well. It's when you're really pushing hard at the track that I've had rear shock travel issues as well as a need for better roll control in general. So I may switch to a more motorsports oriented setup, most likely Moton Clubsports since I've had a lot of success with the Moton triples on my racecar and am well versed in dialling these dampers in for best performance.

kjchristopher, I believe the welded OEM pedal BHR offers is STX legal but those bolt-in pedal braces are not. Am I wrong on this? It's still just an OEM pedal, so I can't see how/why it'd be outside the rules for STX to weld areas that simply secure the two halves of the pedal assembly together in a superior way to the factory tack welds. The pump is another issue, but I swapped that in as part of my continued exploration of why my engine is making poor power up top. It's a 10 minute job to swap the OEM pump back in, so I'm not too concerned about that one. Any news on the legality of the rear wing for STX next year?

And remember kids, it's better to look fast than to be fast

 

There isn't an allowance for

in the ST rule set.

You really can't look at the rules in the mindset described. You have to take a "where does it say I can" approach. In your case, you need to find a rule you can point to that would allow extra welding and reinforcement. If it mentioned the pedal, that would be the cat's meow.

 

Here is what I would call a typical RX8 dyno on a healthy engine with new plugs and coils .
Right up until 7000 rpm the power is pretty much identical . After that yours is dipping away vs a good dyno which improves 10-15 whp from that point . So you are at least 15whp down across the meat of the power band .
Have you adjusted Dwell for the BHR coils ? Are you connections all good ? What do your AFRs look like past 7000 ?

 

Per one of the recent Fastracks, earliest any changes to the wings and body kits in ST will go into effect is 1/1/2012. So things will remain status quo in 2011.

 

Looking forward to the rest of the articles - been following the build in the mag.

S

 

typical fail maybe, otherwise not even close ....

 

Really ? Pretty much all the stock dynos iv'e seen fall into the range between 165-185whp . which forum have you been reading ?

 

I like your note about the reason you edited your post. I appreciate you going easy on me. If I've gotta swap the unwelded stock pedal back in for STX events, so be it. It's actually a very easy job. Three nuts and a couple wiring harness plugs. In any case, since I also use the car for Time Attack events, I'm very happy to have the stronger clutch pedal for that purpose, particularly since I've been chasing a 3rd to 4th gear shifting problem at high rpm and one theory was a flexing clutch pedal causing poor clutch engagement/disengagement.

Brettus: agreed, it does seem like my graph is still not climbing the way it should on that final of the three humps. I haven't adjusted the dwell yet. That'll happen when we do the full retune using the AP. AFRs in the top end were in the 11's and dropped to about 11.2 by redline. If memory serves ignition timing climbed to about 29-30.

chiketkd, cool thanks for the update on that. Glad to hear I should be able to run the wing I recently picked up from wingshop.co.uk. It's a pretty sexy piece of carbon.

Thanks guys. Any of you going to SEMA? Would love to meet some of you rotards and coneheads in person.

Oh btw, that martini shaker cat lost zero hp compared to the resonated catless midpipe. Actually, it gained a bit of power with the martini shaker, but that was probably just because engine temps were a bit lower than the dyno runs done with the catless midpipe. Still, pretty amazing for a HFC to rob zero power while being proven not to throw any CELs. Gotta thank TeamRX8 for tipping his hand on this part and for Milltek supplying it to me at a very fair price.



Another thing that surprised me was how white the o2 sensors and exhaust port looked when swapping the header and midpipe. Even on the most aggressively tuned NA piston engines I've run, with AFRs in the mid to high 13's, I've never seen exhaust ports this color. Is this normal for a Renesis?

 

I've been following the clutch pedal issue for three years now, and I'm convinced the failure is because people unintentionally push the pedal sideways as they push it in. The sideways forces are what cause it to fail. I sit closer than most people do and so tend to push the pedal straight on the plane it pivots on. I've been tracking and autocrossing my 8 pretty hard since I got it (and daily-driving), and check the clutch assembly before and after each event. No significant side-to-side play or and no visible tears in the metal or welds. So do what you can to push the pedal straight in with no side-to-side force and it should last just fine during your STX events.

 

OK Mr. seagull poster, how about posting up what you think a non-"fail" dyno looks like?

 

This was Team's STU Cobb dyno from a few years ago.