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 :o:
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:
https://cimg8.ibsrv.net/gimg/www.rx8...cffa12ca3a.jpg
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.
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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 ?

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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.


https://cimg9.ibsrv.net/gimg/www.rx8...661c9cd47.jpeg
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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
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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
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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 .... :dunno:
I had OEM rx7 apex seals in there and one of those broke
https://cimg6.ibsrv.net/gimg/www.rx8...2384ae47e8.jpg

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.

https://m.media-amazon.com/images/I/...AC_SL1500_.jpg

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.

the effect of runner temp is negligible. even if it was 200C and you have 25C inlet air you maybe get 26C-27C out of it. The velocity and mass of air is very high compared to surface to transfer the heat thus the temp difference is very small. Yes it slowly builds up the temp but its not impactful for the intake charge.

I edited out that last post, had a brain fart. Regardless of the cutoff seal, the open chamber trapping hot exhaust gas and then releasing it into the intake cycle is the issue.

I know you knocked AI in the past, but it really makes a win/lose difference if setup properly. Even water only is better than nothing; it has zero detonation potential and the added AFR of alcohol in the mix doesn’t require any factoring in. Most water only issues come from poor setup/control and injecting too much. The goal is to only add enough to quench detonation and not power output.

AEM etc are fairly primitive systems. To do it properly an injector-based duty cycle system is needed

direct port is best, but the APV runners would need a solenoid control tied to the opening rpm.

https://usrallyteam.com/index.php?ma...cPath=1_68_347
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Have you considered a ceramic piston coat on the faces instead?
Mazda has started coating rotor faces. I heard in the late S2 RX-8 but for sure in the current 8C. In part, to reduce carbon build up.
As you can see in a video from the production line, here: (Ignore the added text - some moron didn't know what they were talking about)

Unfortunately I've already got a system (snow performance). When I searched - none of the sophisticated systems like the one you posted came up.
But yes I will have a solenoid control on APV runner and it will be rpm adjustable.
Plan is for one nozzle pre throttle and a second staged one on the APV runners.
Have the snow controller also which will ramp up the pump with boost so Ican knock back the flow and not drown the engine as it's spooling. Should allow me to start flow at a lower boost but I appreciate it's not ideal.

No .... don't know if that would be practical to do here.

Fair enough. Still think it's worth adding some cooling in those runners as they don't have injectors.

Intake afr away is for IAT /MAD, but vapour replaces oxygen so it has to be carefull, its non combustible (unless it gets super hot :D )
close to intake ports so the water/meth evaporates just before the ignition, not much of the air volume has been replaced and the water/meth evaporation energy has been used as knock controll. This is what Team was saying and imho the only way it wouldnt rob power. But the amount needed is nuch less than for IAT.

​​i think simmilar way as it is used on bmw m4 (which also uses snow performance as oem if im not mistaken)

People always reference piston airplanes, but there water was used to efectivelly reduce power as it was to much at "sea level". Ie engine was built for 0.7-0.5 MAP and at 1.0Map it would knock.. So they sprayed with water and used up a lot of heat energy converting it in to vapor, preventing knock and reducing engine power.
The latent energy of water is huge so a lot of heat energy that would be usedfor expansion is used for vaporisation.

Ps, this system posted above by Team is a " the tits" :) something I was looking for / tryingto design formy 2.7bar boosted piston engine

No idea what you are saying here ....

oh the beauty of my autocorrect on the phone and my terrible English (as its not native besides Norwegian, Hungarian, Croatia, Serbian and a little German)…
lets correct it on a PC:
Injection far away from intake is for IAT / MAD (manifold air density). ie, that will not necessarily help with knock prevention. Vapor replaces oxygen (air in general, buy O2 is what we need) in the intake charge so it has to be carefully added only as much as we need, and that needs to be carefully calculated. water vapor is obviously non combustible (unless it gets super hot like above 1500C :D ).
Injection close to intake ports so the water/meth doesn't evaporate before intake is closed, and evaporates just before the ignition in the combustion chamber, not much of the air volume has been replaced with vapor and the water/meth evaporation energy has been used only as knock control. This is what Team was saying and imho is the only way it wouldn't rob power. But the amount needed is nuch less than for IAT.

Ah , got ya now. This is exactly what I've been trying to understand via internet searches and not really getting anywhere with. Thankyou.
I have IAT relatively well controlled and ethanol was taking care of detonation up to what I call the 'zone of death' (past 7500rpm and 400g/s).
My strategy heron out is to just avoid that zone (by dumping boost) and take care of knock up to that point while preventing carbon buildup with w/m.
So maybe I should just use a small nozzle pre throttle and put a larger one as close as I can to the ports?

if your IAT is managed than I would put them only near ports ( i see no benefit at throttle body, you are just making the intake charge moist) . Remember, the less you have added, the less variable is in the system and less failure points.
while you are on a MAF base map, you are ok and you will immediately see the impact on air mas flow, but on a speed density maps, it can get very confusing very quickly :)

I think a small one pre throttle could still be worth it for those occasions when IAT can climb ... IE heat soaking at idle etc. So you get some IAT cooling at low rpm for initial takeoff etc. I think it's also not good to dead head the solenoid at high pressure (300psi in this case) so having one at throttle allows use of a check valve with a lower cracking pressure (40psi).
So for the other nozzle(s) how close is close enough for the effect you describe ?

What are your average IAT's ? I need to do some math :)

probably didn’t understand my post fully

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the guy probably forgot more than I know :D he's a genius :)

Interesting talk ...........not much on the 'how to' side of things though.
Listening to that makes me wonder why NONE of the literature from the mainstream supply companies even attempts to explain how to achieve what he was talking about.
It's all "Shove a heap of water in before the throttle body and call it a day" !

Which would explain why my early attempts failed and why no-one else seems to have made big power with this method. Everyone has treated it as "insurance" and not really attempted to get the moist ....or the most, out of it!

Do you mean in NZ? Surely there's some shops doing it. I have the stuff to do cerakote at home. But they're here in the US.
I'll be trying it out with my next rebuilds. Hoping it helps keep the carbon buildup from getting too bad.

I would be careful with Ceracote.

it’s what Rice Racing has been doing in AUS for a long time, he doesn’t get enough credit for it
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If you can afford destroying engines finding out the hard way, then more power to you.
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Well, that's counter the advice from some who have race development experience (and Mazda, above). Note, I'm talking about the TBC (thermal barrier coatings) not the lubricating side skirt coatings. The side skirt coatings don't help since the rotors float.

on a short lived, unlimited $$$ professional motorsport race engine maybe

think about what happens if even one small flake chips off, might as well not run an air filter in the Sahara desert.

you mean well, but people who don’t truly understand the real world magnitude of certain concepts tend to misperceive an ant hill as being Mt. Everest, when it’s not.

it’s not like you should focus first and foremost on learning how to build a respectable, long lasting Renesis engine first, let’s throw a bunch of variables you read, heard, and convinced yourself of in the imagination of a of a glory seeking heart about, but have no actual experience with, into the mix as well. It’s only money and it grows on the tree in your backyard, right? Just go out and pick some more whenever you want, no problem.

I guarantee you wouldn’t be the first person on here to invest in it and not only never see a true benefit, but feel the loss of financial investment as well. Put together an engine with less than optimum used parts and put your money in that instead. Yeah, that makes sense.

As it was said, “the heart deceptive above all and exceedingly misleading; who can know it …?”
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Mazda is definitely not interested in coatings that only last short term. Anyway, I have good info from better places so just trying to share.

Doing something in a factory aplication is not near what you can do afternarket..
The substrate for a good coating is not any material, it is a material chosen particularly to be able to have a very good adhesions with the coating.
It is done on VIRGIN material, that has than been chemically further cleaned and activated. Not something that is cast iron that wil absorb oil like a spunge

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