I'll get the upgraded stationary gears....but I don't know what upgrades the trans can take....may just leave it a 6lbs boost....I'm getting ready to rebuild motor

 

I have no idea either but I'm sure there must be people who work on drag race autos who could steer you in the right direction.

 

I'll ask around

 

The car has been an absolute weapon. I was surveying the virtual dynos and realised ..... the goal I had from years ago was within reach ! Over 400whp with a flat torque curve of 300lb/ft over the entire power band. This was something I've seen done over on the rx7 forum many times and always thought would be so cool if it could be achieved with a Renesis.
Looking at my logs I could see that all I needed to achieve this was another 0.5psi of boost. I'd already run at that boost (14psi) previously at a couple of events so didn't really see any danger. It was a cool summer evening (around 20C). I'd just finished giving it an oil change, air filter clean and topped up with my ethanol mix (E22). I'd also opened up the restrictor on the APV a little a week or so previously which I should have taken into account
Started the run in third gear and everything was going great ......... right up until 7500rpm - then I heard it ...the death rattle!
Knew instantly that I'd killed it and my heart sank.
Couple of days later I pulled it apart and surveyed the damage - broken apex , chewed up rotor and housing. Remarkably all plates were fine.

 

Here's my best guess as to what happened :
1/ Engine was at or close to it's limit wrt exhaust gas expulsion and EMAP at it's highest point.
2/Should really have had more ethanol in the mix running it at this level (E30 or more)
3/Maybe a little too much timing ... 10 degrees
4/Carbon buildup on rotor was nuts - after less than 10,000kms of use. I calculated this brought CR up to approx. 10.25:1
5/ This is the kicker ......... I never saw the rotors after balancing and never would have allowed the engine to be built if I had !!!
whoever balanced the rotating assembly obviously didn't understand the Renesis because they had machined the sides of the rotor and basically created a pocket for exhaust gasses to transfer into combustion chamber. See pic below:

Note the machining on side of rotor (0.8mm deep) plus carbon buildup on combustion face.
This is the side of the engine that failed. Front rotor without this machining was fine.
Not only did they machine the sides but also the upstand beside the outer scraper seal was removed leaving a small upstand between the pockets. The remaining upstand was obviously wearing excessively due to being the highest remaining area left on the sides of the rotor.

 

Is it now time to give in to the rew/cosmo ?

 

dang that sucks...wish they machined it right

 

Not at all .... I've come so far now and totally believe the power band created above can be achieved and made reliable (maybe a little less aggressive at the top end).
Yes - transplanting an REW in there would give me that power with relative ease but this whole journey has been about maximising the Renesis and doing something that can be repeated by others. I'm too invested in that goal to quit now.

 

that's what I love about what your doing for the Renesis....keep it up man ...and thanks

and the machining error was a big part of this.
get it back and right and do the R&D, and share the info...I'm turbo'in my Reny

 

Brettus, sorry to hear of the setback but I know it's just that, a temporary setback and then you'll be right back at it!
keep it up man.
been awesome to see you get this far.

 

ooph, same thing I warned Ricky about … sorry to hear of your troubles.
.

 

Sorry Brett, this post came in before your last post (or for some reason I didnt see the last post with the rotor and "post analysis")

Seeing this I absolutely understand why you would like to keep it going longer / harder in renesis setup

Its a bummer. Is this the engine that has the PP exhaust port as well ?

does polishing rotor faces help with carbon build up ? TeamRX-8 ?

but what has failed in the end ? corner seal or apex ?

 

.
https://www.rx8club.com/series-i-maj...4/#post4972347


it basically overrides the cutoff seal function in that it creates a trapped chamber of hot exhaust gas that transfers directly into intake port/cycle as the rotor tip moves across it. i.e. hyper-EGR

Mazda added material there compared to past 13B rotors to minimize volume and that modification does the exact opposite.



.

 

well I still have that same pair of lightly used Renesis rotors with RX7 apex slots on the shelf if you’ll accept them.

lmk
.

 

I do accept them :D (i know im not the one asked :p)

I understand the pocket and how it all created detonation. I was wondering what gave up first.

​​​​​​So an engine not having an "EGR" at WOT will make more power for same setup and less boost :D

 

edited, wasn’t visualizing it correctly in my mind
.

 

Hence why I called it EGR

 

The pp exhaust engine is NA.
These rotors WERE polished and the carbon is stuck on really hard .... I compared it to some other rotors I have here from an NA engine with way more kms on it (I assume) and the carbon on those buffed straight off with a wire wheel vs my turbo polished rotors where I virtually have to chip it off with a chisel! Something about ethanol/premix/omp oil ....
I had OEM rx7 apex seals in there and one of those broke

 

Team ... The raised ring is actually still there between the two pockets ...they didn't machine that out. This left a small raised area in three spots, you can just see at top of this pic. That area was rubbing on the irons and wearing very quickly. I'm really pissed that this was done without my knowledge and wonder what I have to do to avoid the same thing being done again!

 

So, for my next trick :

1/Water methanol kit is on order .... want to give this another go for two reasons. Ethanol is getting really hard to get and very expensive ($120 for 20L) and I really want to avoid carbon buildup on the rotors which w/m injection should help with. Going for a two stage setup and plan on getting a decent % of the mix into the APV runners.
2/Lower compression Renesis rotors (9.5:1). I aborted my attempt to run lower CR Renesis rotors on this last engine because I had waited over a year and just got impatient and gave up.
3/Have sought help from a well known racer/engine builder here. Being able to bounce ideas off him has already been helpful and I'm hoping he can help at the dyno tuning stage as well.

 

Brett,

Can you get this there?

This is what I run with charge pipe injected setup on my 335i, it also run full E85, this is mainly for lowering intake temps and leaves less gunk than the typical water/methanol did.

 

That's a fuel at that ratio so wouldn't that be risky in the engine bay ? Presume you have the tank in the boot?
What's this "gunk" you mention with w/m .... never heard any mention of that?

 

Yeah My tank is in the trunk. Even though I used distilled water and methanol, I had a green build up in the tanks and in the tubing, on the nozzles, etc. That was after a few years use but since running this for the past year or so, the nozzles have no build up at all. But VP is local to me and this stuff is pretty cheap. Ethanol is also cheap here though too.

 

Well cheap source for ethanol (above 50%) is winter washer fluid concentrate. It is not taxed the same way as others... That was my alternative source as pure is not awailable for private purchase (has to be a company with a very good reason and documentation on where its being used up).

Yes, anything above50% is flammable and should be treated as fuel. The worst is its burning without any colour or smoke!

The deapest research I found wjth akk tge detail have concluded that:
- Running it as additional fuel as safety pusher the afr to rich and makes same power as with lower boost and no need for additional cooling/fuel or if overdone extinguishing the flame.
depending on the ratio of water / alcholon, the burning speed is reduced significantly such that the max pressure is happening 40-50° at 4000rpm ATDC insted of few deg ATDC..meaning that the ignition would need to be very early bulding up much highet pressure BTDC
- using it as a fuel, mapping the ecu as if less fuel is needed with all the benefits of ethanol or methanol. But the risk of it not delivering for what ever reason and leaning out the engine.

I read your post on fb about Haltech and maybe it would be safe enough to run it wjth a very tight fail safe on AFR vs Boost.

 

Not in this country .... have looked before but will try again. I think you meant methanol ...which I can buy here relatively cheaply , only $70/20L vs $120 for Ethanol. To me that's very cheap considering I was putting 10% ethanol in the gas and using it for cruising as well as boosting.

Yeah, I'll be leaning out the fuel mixture rather than treating it as insurance. Have a couple of safety strategies I can employ to prevent a leanout. The AEM failsafe gauge can dump boost if it gets lean. Plus I have a pressure sensor I can run in the w/m line that I can use to activate a relay and dump boost if there is no w/m pressure as well, which should be quicker acting than the AEM.
And yes the Haltech could be better than either of those.


IMO- we need to get some fuel/cooling down the APV runners. If you measure the temp on outside of these after a run ...they are consistently 10C or more above the other runners, due to the fact that, under 6000rpm there is no cooling air passing through them. I believe this is a much overlooked area for improvement as the potential for this runner to be supplying much hotter air into the combustion chamber and creating hot spots is very high.