Perhaps one theory has now been proven; discussive/argumentative threads such as these tend to run in circles. Once we at BHR become too busy testing what we think we know about this stuff, we will not have much time to discuss it. Interesting paradox? Or something for everyone to look forward to; BHR's silence.........

 

your only argument is that no matter how many times it gets spelled out you are still stuck in a 13B mentality that has yet to grasp the Renesis engine reality.

 

Thanks Rote8-----appreciate the info. I am seriously considering this .Cam has a set but they were machined for the 3mm apex seals and I dont know about that.
For the hell of it I am also talking to Swain coatings.
Anyway, all of this lead me to call Cam and Rick. After some discussion with Paul and Cam they are going to talk about this themselves. Owe it to you Rote8---you da man.

I anticipate starting an engine build in Feb.
Zoom--- I owe ya buddy. You helped bring all this info together.
Merry Christmas all!
OD

 

Out of curiosity why do you think the MSP is so different than previous 13B's. As I have heard you make this statement over and over again.

I am not trying to make this an insult, so please do not take it that way. It is simply a question. Have you built any prior 13b's or 12a's?

Have you ever looked at the S5 N/A motors in comparision to the renesis? I just pulled one yesterday and will rebuilding it after Christmas. I would be happy to post up pictures. I don't have a renesis on hand at the moment to compare it side by side, but you can see the similarities. There really isn't much difference than the CR is 9.7 compared to 10, exhaust ports, and the extra scraper seals. Otherwise they are almost identical in short block form w/ the front cover removed.

If you would explain it to me why you think its is so drastically different in your eyes it would help me understand where you are coming from. You may PM me not to deter from this thread anymore than what has already transpired.

Thank you.

 

You're welcome. Come to 7stock sometime and buy me a beer

Here's what I'd like you to seriously consider Denny.

Skip dropping the compression. Raise the RPM limit back up to like 8300, drop the spray and convert to E85. If you do you should be able to conservatively up the boost to make 350 at the wheels safely. AND you will have an altogether LESS complicated system.

Take a serious look at the cost differences and look at how many E85 stations you have available to you. http://e85prices.com/georgia.html . theres at least one right in Macon and I think it says 41 one in Georgia.

Start with your fuel

 

I think a few people have that on there Christmas list.

Ho Ho Ho

 

I think my rotors are the 2mm seals; I have been wanting to build a spare engine soon as well.

I suspect Cam may be busy making hybrid rotors for a while...

 

The biggest differences between the old 13B's with peripheral exhaust...and the Renesis..is the outflow in the Renesis has to make a nasty 90 degree angle to get out of the engine........

Other than that...everything else is better...bigger ports, no overlap...etc

 

Zoom--beer will be on me.
E-85 is interesting but no clue on how to convert and or tune for it.
Different world.
Has anyone done this on a DD car?

 

My opinion....ive never built an engine. But going by my research, the Renesis can injest more air than any other stock 2 rotor engine. But on the flip side it cant expel as much exhaust as other engines. Which makes it a little more challenging when it comes to turbo selection. I feel like you cant just slap on something that worked for previous engines.

Secondly. As far as the low horsepower @ 10psi... i will say with most turbos, the Renesis trounces the 13brew in whp comparison.

Lastly. As i said in my 1st point, airflow/exhaust behaviour is not exactly like previous engines...if u lower the compression youll need more boost to reach the same numbers. Well good luck with finding a boost option...EXHAUST LIMITATION is physical. U get the picture??

 

You are not giving the REW the credit it deserves, and you would be disappointed in the results.

[/QUOTE]Lastly. As i said in my 1st point, airflow/exhaust behaviour is not exactly like previous engines...if u lower the compression youll need more boost to reach the same numbers. Well good luck with finding a boost option...EXHAUST LIMITATION is physical. U get the picture??[/QUOTE]

Thanks for the info guys, but I was asking Team, and I have built both renesis and older motors for different apps and I am fully aware of the differences. This is also why I asked for it to go to PM so that it does not clutter this thread.

 

I like my low compression rotors, for the same blower speed, the extra volume means less PSI per engine rev, but also lower intake temps and lower engine temps. (when you do not run it hard)

I keep telling myself I may decide to run 83 octane one day with the tune I am running.

Make sure you port the end and intermediate plates, and that the porting and the resulting port size is the same for each rotor chamber.... (Or let Cam and Rick port it )

 

It's pretty much as simple as using lamda to tune and having the fuel system to handle the increased flow

 

Yep--understand the need for using lamda, and having to deliver more volume,
but I am wondering about any downside. Any water issues noted etc.
Worth another thread?

I have decided at this point to go with the low cr rotors. Build starts in Feb--have to source new housing etc, Rick and Cam have to talk and since Cam is a long way off, Steve Kan will do the tuning when he visits Atlanta or if Kane is back by then maybe he can swing by.
Low cr rotors will not be the only change I make. They will also be better balanced.
Swain will be coating the exhaust ports (havent decided on the rotor faces yet), they will also coat the inside of the rotor to expedite oil flow/drain.
looking at what can be done to the side seals, will use oem seals
will have to port just a little,
looking at changing the oil pump and using the 09 pan
modifying the oem oil coolers
of course i will be bumping up the s.c. drive to get approx 300rwhp.
I am sure other stuff will come up.
This build is part of my "bucket list" guys, I am 61 yrs old and my car days are not going to last forever.
Who knows I may bump up my redline to 8K

 

I'm in a "every lower displacement turbo engine that has ever made power" mentality, not a 20-year-old 13B mentality. It's not like I only work on or tune rotary engines. So let me ask you, what is the "Renesis reality" that I am missing? yes it has side exhaust ports. I know that. The reality is that on pump fuel only, with 10:1 rotors and thousands of dollars spent you're stuck at low to mid 300s to the wheels any way you slice it. That's the only "Renesis Reality" that matters.

Something's gotta change and increasing the fuel quality beyond pump fuel is not practical for a lot of people.

 

again, your statement above clearly demonstrates that you are not

in general, most of the stuff you read about on this forum lags the leading edge knowledge base by about 3 years or so

 

61 is the new 40! I'm sure you'll keep doing car mods like a teenager for at least other 20 years
Have you considered moving to a bigger supercharger? I won't tell you to move to the light side of the force, you would hate me for doing that

You're missing the point that there are not many cars running turbos capable of producing the flow needed to go past the 350rwhp mark. It may be a matter of compression for some, it surely is a matter of turbo selection for most.
Esmeril and the likes did crap jobs that bit the dust soon, other guys are producing better results with better tuning, turbo choice and build quality.
Given our very small market window there's not much talk about that but that's just the way it is.
In both cases, x:1 or 10:1 compression ratios you'll still have to face the side exhaust ports limits and that may happen before you reach the need for lower compression.
I will also say, again, that peak power means close to nothing. Our setup's output has got other strength points that go beyond raw power.

 

I want to see a low compression, ported, 20 PSI forced induction motor, I don't care if it's turbo or blower, but the low comp rotors can go way higher on boost than the stock ones.

 

That would be a nice starting point but still, talking about pressure is not enough.
You could find a turbo that flows the same at lower psi rates :p
We should focus on finding the 10:1 compression ratio limits in grammes per second and work from there as i'm fairly confident that its limit is pretty high for our goals.
There's a point where getting more boost with a given turbo to produce more stable power may be beneficial but i sincerely don't know where that point lays!

 

AAAARRRRGGGGHHH FLOW FLOW FLOW!!!! how much air do you want?

 

About 1500m^3/h should do it. I might be about happy then.
Might need a slightly bigger gearbox mind.

 

In case it was missed...

Quote:

an 80 ci engine looking to move 50 lb/min of air would be operating at a MINIMUM 200% load at 9000RPMS

That is 2 ATA, or 1 ATM with no temperature variations - or .42 PPO2 for those in the cheap seats..... That is the motor's limits, not the compressors'. If you want more than double the power of a stock RX8, you are going to have issues with regards to the compression ratio.

Pretty much everywhere below that threshold; higher CR is mo' betta'.

 

Is that really 882 CFM? I am not sure if my conversion math is right.

 

TWO 90° turns at each port.

Why is it that, as many times as we beat people aver the head about mass-flow, the "mass" part of that gets ignored?

If you take a bullet and throw it at somebody, you get a different reaction from that somebody than if you fire it at them. But why? The bullets have the same mass, don't they?
The inertial component of the air is not trivial. Asking it to make two turns perpendicular to the direction of combustion flow at the much higher velocities at the exhaust stroke is not an inconsequential request.

 

^^ I bet it still doesn't sink in