Build Thread: RX8

[crzyone]

Oh yeah, forgot you had that installed.

I've actually talked about this with my engine builder and read quite a bit about it. The straight injection in the middle of the housing actually works pretty good since all the oil gets distributed there instead of being in an atomized form in the fuel. It may or may not contact the wall of the housing. Adding a little 2 stroke oil as well as keeping the injection seems polpular as well. Don't need much, just supplimentry oiling. This will help out the side and corner seals more than just the oil injection.

I'm putting my AEM water/meth from my GTR on the RX7. It keeps everything nice and steam cleaned in the housing. Guess the apex seals getting gummed up and stuck is common. The injection helps clean them and keep the heat down a bit. Going to RP synthetic probably helps this out a bunch as well.

[AkursedX]

Oh yeah, forgot you had that installed.

I've actually talked about this with my engine builder and read quite a bit about it. The straight injection in the middle of the housing actually works pretty good since all the oil gets distributed there instead of being in an atomized form in the fuel. It may or may not contact the wall of the housing. Adding a little 2 stroke oil as well as keeping the injection seems polpular as well. Don't need much, just supplimentry oiling. This will help out the side and corner seals more than just the oil injection.

I'm putting my AEM water/meth from my GTR on the RX7. It keeps everything nice and steam cleaned in the housing. Guess the apex seals getting gummed up and stuck is common. The injection helps clean them and keep the heat down a bit. Going to RP synthetic probably helps this out a bunch as well.

Yes, the 13b has a much better oiling system than the 1st gen Renesis (The 2nd gen Renesis has the center oil injector.). I'm pretty certain that you won't have an issue with lubrication or build-up if you are using the water/meth injection.

One thing I will mention though it that regular motor oil was never designed to burn, which is what causes a lot of the buildup inside the engine. Premix is designed to burn in the combustion process so it lubricates without as much build-up. My exhaust-tips used to be blackened with soot when I was still using the stock oil injection. Now with the premix being injected, I only get a light-brown tinge to my exhaust tips. I'm hoping that's a good sign as to what's going on inside the engine.

Has your engine builder said anything about not using Mobil-1 oil? Apparently there is an additive in Mobil-1 that is very destructive to Renesis engines (When it's used in the oil-injection system) and I was wondering if it's the same in the 13b world.

[crzyone]

My engine builder and myself just use regular castrol oil. When I get my car back on the road I'll be switching to rp. They even have a decent blurb on their website saying its ok for rotary engines.

I've stopped using Mobil 1 in everything since they went from a group IV synthetic to a III.

[AkursedX]

Note: This update was from late June. I forgot to post it up here:

I have actually been driving my RX8 a lot more than I have been working on it over the past 2 months, but I finally decided that this week I was going to get some work done on it.

The first thing I did was change the oil. After reading all 78-pages of this thread, I decided on using Royal Purple 0w40 synthetic oil. I also 'upgraded' to the 2nd generation oil filter as it's a bit larger. A paltry 4qts drained out replaced with some fresh oil and a new filter and I should be good for the summer.


Here's a side-by-side of the 1st gen filter vs the 2nd gen:


And an installed pic of the new filter:




I also finally got around to upgrading my brakes! Everything went pretty well and straightforward. Even the rear calipers spun back in with little difficulty. All the slider pins were still free and greased. This makes doing brake-work much easier, haha.

While I had everything apart, I painted the calipers and dust-shields. I also applied some 'Mazdaspeed' stickers from Polak Graphics to the rotors. The calipers were done with a blue-caliper-paint-kit from the parts store and the dust shields were painted with some high temp engine paint.

The pads are Porterfield RS4's all around. I bought them from www.lpiracing.com as they were the best price I could find. They shipped out real quick and I had them within 4 days. The front rotors are EBC USR (From Summit Racing) slotted rotors and the rear are Centric Cryo-treated rotors (www.tirerack.com)

I have done no other driving other than bedding the pads in, but I am happy with how everything is working right now. The pads definitely grip strong.

Pics:
New front:


New rear:


The color-changing fronts after I bedded the pads:




Up next, I think I am going to add an aux. jack to the radio, and I think I'm going to pick up a stock spoiler or possibly a GTO spoiler and install that.

[AkursedX]

Well I haven't updated this in awhile so I think it's about time I put something up.

Exhaust Problems:

See THIS thread for more detailed info. Basically my Corksport midpipe has proved to be a PITA. The aforementioned thread covered the 1st problem. Once again, I would like to give Bryan of BTEK Fabrication props for re-welding the resonator for me.

After the conclusion of that thread, the midpipe lasted about 1.5 weeks until the opposite side of the resonator burst open and cracked all around. I had Speed Industry in Troy weld up the other end for a few bucks. I will be reinstalling it today. If something else breaks on it, I'm throwing it in the garbage. Needless to say, I wish I would have gone with a different mid-pipe.


This pic shows the 1st break of the resonator. You can see some of the fiber packing sticking out:


Here's the BTEK-welded side:


And here's the Speed Industry side:


Drag Strip

Last week (8/4), I had some free-time and headed off to Lapeer Dragway to see what kind of times and MPH I could get out this car. I went up there not expecting much as it was over 90* by noon. With the rediculous heat, there were only 20 cars at the strip. To get an idea of the loss of power, there was a stock C6 Z06 there that was only running low 12's and didn't trap over 120mph.

Anyways, I made 4 passes. My best E.T. was 15.44 (Worst was 15.9xx) and my best MPH was 95.20MPH (Worst was 91.88MPH after banging off the rev limiter in 3rd).

I can't say I was happy with the e.t.'s, but I was happy with the MPH. Considering my IAT's were anywhere from 111* up to 130*, I was happy to trap above 95.

Observations:

-I can't launch this car to save my life. My 60ft's were anywhere from 2.48 to 2.81. I tried a few different RPM's and tried to feather the clutch, but man it's tricky. Plus RX8's seem to wheel-hop a TON. After reading other threads about RX8's at the strip, I realize that I'm not the only one who suffers this ailment.

Also, I have made over 60 1/4 mile passes, but they have all been with an automatic. This was my 1st time taking a manual car to the track. Although I think that my only other manual car (A Mustang SVO) was easier to launch.

-The 3rd-to-4th shift is quite notchy. You really have to *bang* it into 4th. And you really need to make that 4th gear shift although it's almost near the end of the track.

-I found that shifting right around 9000 on the tach (about 8800 according to the AccessPORT) yielded better results than running up to 9500. This makes sense when you look at the RX8's powerband on a dyno-sheet.

I hope to make it to the strip before the end of the season. I hope to do the Poly Engine Mount DIY which should hopefully help with some of the wheel-hop. With some cooler weather, the mounts, a tire pressure drop (I didn't bother dropping it this trip), and most importantly, more practice launching, I might be able to crack a mid-14 and get closer to 100MPH.

Body Mods

Rx8club's forum member Rzoops is my inspiration for the look I wanted for my RX8. I have already purchased the same RPF1's and now it was time to change some body parts. I ordered front splashguards through my friend Hank at Ralph Thayer Automotive. He's the Mazda Parts Manager and will give 15% off to enthusiasts (Mention 'Joe with the RX8') and he should hook you up.

I then ordered Rear Aero Flares from ebay member AZPartsExpress. They were $118 shipped through them (A price that no one else could come close to. Most places were over $225). They took about 3 weeks to get to me, but they were genuine Mazda parts so I have no complaints.

Installation of the splash guards went pretty easy and took about a 1/2 hour. Installation of the rear aero flares took a fair bit longer as I had to remove the whole rear bumper. Some of the fasteners were a PITA to get off. The two bolts that are held by square-nuts molded into the bumper both stripped and I had to use vise-grips to hold the square nuts to get them undone. I then replaced those parts with a stainless bolt, nut, and washer.

One nice thing about installing the rear aero flares was that the bumper had punch-marks in it to indicate where to drill. This took virtually all the guesswork out of the alignment.

I am very happy with the turnout of my work and in my opinion, it has really enhanced the look of the car. I still think I am going to add either a stock rear-wing or a GTO rear wing.