I must also say that if anyone is looking to the 7club forum for engine failures, please understand that while that forum is the largest forum in the world for rotaries, it also has the single largest number of rotary owners who are either too impatient or too cheap to do things properly. What they don't lack is people who are willing to go out on a limb to try something that is unproven. There are very few cases over there where you see an engine failure and can't directly relate it to something that the owner did that made no sense, made a mistake, or took a short cut on.

The rotary is quite reliable. Unlike piston engines it just doesn't have a tolerance for stupidity or mistakes. Many owners tend to underestimate the importance or difficulty of rotary tuning. This leads to more failures than anything. Combine this with some aftermarket companies who provide cheap poorly tuned/designed equipment, and you'll see engine failures. You can go over to the 7forum and see people who sells their carbs because they can't make it run good. Learn how to jet a carb!!! Then you'll see people who buy standalone ecu's and install them, get frustrated because it doesn't work perfectly out of the box and sell them!!! Learn to tune a damn ecu! People are impatient. They want instant gratification on a product that needs to work 100% perfectly on their car with their setup right out of the box, and it needs to be cheap and easy. See the issue?

Stupid people/companies give the rotary a bad name. The engine is more than proven. When you narrow this all down and eliminate all the mistakes that were made in one way or another, you get a number of engine failures that is on par with any other engine out there. Things happen sometimes but not nearly as often as many make out.

One more thing to keep in mind. You'll always hear about the people who blow their engines up. When was the last time you saw someone start a thread that said their motor was fine and working properly? If everyone did this, you'd be hard pressed to find a negative thread. People don't though. It's the negative that gets more publicity.

 

I love following arguments without supporting data.I can add a little real data but I don't think it will change anything.
1.My first Turbo II ran out over 100k miles just before I sold it.I have not heard from the guy who bought it so I think it may still be running.The main thing here--no modifications other than removing the warm up catalyst.Regular maintenance.
2.My second Turbo II had 2 engine changes before it got to 80k miles.Factors here were crappy maintenance for first engine failure,inadequate tuning for modifications made for second engine failure.
3.My RX-8 engine failure due to crappy fuel and stupidity of owner.

BUT---both the engine failures(TII and Renesis) I had were due to detonation breaking an apex seal.In both cases failure occurred when I was pounding the motor(read racing) and there was no long period of detonation noise(I mean 1-2 seconds).
The apex seal failure mode was identical in both engines-they broke at the pointy bit,piece breaking off about1/8-3/16 inch. (see attachment)
I am not the least bit worried about breaking a side seal--I have never seen a broken one.

Properly used and maintained your RX-8 motor should easily go 100+k miles.
If you go FI ,properly tune the system,ensure good fuel,and keep boost below 7-8 psi you should go 100k without failure.
Like anything else the harder you push the more likely you are to screw up.

 

I hope that the renesis does go 100k miles with no problems. If I am wrong about the statements that I made earlier, then I am wrong. I just know that I like the RX8 and hope that it doesn't give me any problems, assuming that it is properly maintained of course. I would just like to address the power output with FI reliably, that is all.

 

then stop posting and read, i highly reccomend that

 

Yo, GL. Sounds like u will be joining me w/ the 3mm seals. I hope u get it back in a week. The guy doing mine got in a bad accident in his 20b 7, and was in the hospitle for 2 months! I'm glad he was ok, but just as an understatement, I definitely waited a while to get it back, so hopefully u won't have to.

 

[QUOTE=rotarygod]You can use Renesis rotors in a 13B but you can not use 13B rotors in a Renesis. Without getting into alot of detail you'll have to trust me on that one. /QUOTE]


i'm gonna be using s4 rotors in a renesis later on, but it'll have renesis side seals 5-axis cnc + crack for the machinist = sky's the limit

 

this is pure heresy!!! BLASPHEMY EVEN!! How dare you bring such radical notions to the forum....AWAY WITH YOU AND YOUR HERESY!!! WITCH!! WITCH!!!

 

She turned me into a newt! Burn Her!! Burn Her!!

 

i still gotta get ahold of a 4-port motor to do that to. i don't wanna spin s4 rotors up to 9k...

but what's wrong with a 450 whp renesis motor that passes emissions legally?

 

ok, the turbo technically makes it not legal, but it'll pass the sniffer anyway.

 

I passed the OBDII computer test. Lean out ur idle and it works every time .

 

Ok. I'm trying to learn so I can understand these things better and see how turbo sizing works better.
From what you wrote yesterday, the TD06-18g flows enough air and no one wants to agree with that. I asked for compressor maps and cant find them and you stated that the only part that matters is the TD06 as 18g refers to the turbine AR..

So if that's the case, a compressor map for a TD06-20g should be similar, right?

Now, I know how to read a map, which is actually pretty easy (considering you taught me how in one of your earlier threads). I've plotted the flows based on the TD06-20g and the calculations you provided and if I did this right, it looks like this (my numbers may be off a little, but if anything they're just a few points to the right, again my work here is an approximation)...

This is the first time i've ever done this so if it's not right, it's not right..
From the plotted numbers though, running 1.6bar (8.82 psi above absolute) this turbo is in it's efficiency range at 6-7k rpm and starts moving out of it by 8k rpm and is well out of efficiency at 9k(into 70%).

at 1.8bar (11.76psi), things look a little better as it's still at 73% at 9k and the same is true at 2 bar (14.7psi above absolute).

So I guess this would be why you would say that this turbo isn't too small. Assuming this turbo (TD06-20g) is similar enough to the greddy turbo (T618Z or TD06-18g), that would be true.

 

The 20G actually refers to the compressor wheel size. At 70% you're still in a great place. Your compressor map calculations are off though and I'm not understanding what you did with your plot.

 

Yea, I know they're off. I can't exactly figure out where. It's not much though going based off Jeff's initial numbers, i get 241CFM (17.6ppm) unboosted at 8k RPM and I get 354 (25.6ppm) at 7PSI... that should be 23.6ppm.. so i'm off somewhere in the boost calculation. it's not a large amount. it just shifts all of the RPM points left a bit.

The plot is 3 boost settings, 1.6,1.8,2.0 bar. I calculated the PPM/CFM for each point at each different boost level in 1k RPM increments and went from there. The first dot on the left is 2k RPM and it works up from there to 9k.

 

At 8k unboosted the Renesis will flow around 340cfm. At 7psi and 8k the turbo will be flowing 470 cfm.

 

that's at 100% efficiency though...
And yes, those are almost exactly the numbers I get with 100% efficiency.

 

The Na version is with a VE of 93%, picked based on some data from Hymee. Sorry made a mistake on my previous boosted calculation. I used the air temp out of the intercooler instead of the turbo outlet. I corrected it. It is calculated at 70% compressor efficiency.

 

Hrmm. If that's the case then my numbers are off by quite a bit.
Blah.. i'm tired of math, lol.
If it's as high as you say, i'm actually off to the left.. which pushes the top end a good ways..

 

First of all, you have to assume a 75% average VE. While the intake setup makes it possible to have an effective VE above 100%, there are ranges that will be far under 75%.
More importantly, you will compute your maximum airflow at maximum RPM, which will sport a VE of 75% at best.
All you have to do is look at a dyno plot of an N/A Renesis and compute the torque output at maximum RPM as a percentage of max torque.

At a 75% VE, the maximum airflow of an N/A Renesis is only 319 CFM.
At 9 PSI, you should be able to push about 471 CFM.

Using these values:



and assuming a 1.5 PSI drop across the IC and .5 PSI drop across the intake of the turbo, you obtain this flow diagram:



Now, that is a TD06-16g.

Enjoy.

 

That's extra timing on top of the timing we're already pulling. My reasoning is that I don't want the engine to pop due to a boost spike, so having that extra protection (pulling a buttload of timing) seems valid.

Does xylene do anything funky to the engine, like build up deposits or bugger the seals? If its safe to use, I will definitely do so. Thanks for the tip!

10,000 miles / 280mi/tank = ~36 refills/year.

$21/3 gallons of 100 octane - $9/3 gallons of 91 octane = extra $12/tank

36 * 12 = extra $432/year

$5000 for engine rebuild / 432 = 11.6 years to equal the price of a blown engine

Yes, 3 gallons of 100 unleaded is close to $21, but I only drive the car about 10k miles per year, so it will take a while for that to add up to the $5K + inconvenience of having to replace a blown engine.

 

Wait. You are using the IntX, right? So, you aren't "pulling" timing up top, you just aren't advancing as much. What is your actual peak timing at full boost?

Nope. Xylene is a normal gas additive. It is safe up to 20% of total content (about 3 gallons, which would make your total octane 96.8 or so).

 

No, I'm using an XEDE, which takes full control of fuel & timing like the Interceptor. If I remember correctly, we're pulling about 2 degrees of timing per # of boost. So, the EXTRA -15 degrees on overboost will hopefully save my engine (& marriage!!!).


Cool tip on Xylene...I'll have to read up on it more.

 

meth injection

raise the octane, richen it up, and it only activates under boost, so you don't waste it cruising.

 

Pulling it from what base timing?

Problem is there are too many passages in the IM. The distribution would never be right.
Plus, that is yet another tank to fill. And it is gay. Sorry.
Water injection is on my short list of things not to do that includes nitrous and electric superchargers.

 

it's gay compared to bringing xylene around with you for whenever you fill up?