Mailing List flyrotary@lancaironline.net Message #40195
From: cbeazley <cbeazley@innovista.net>
Subject: Boost without intercooler [was MAP port location]
Date: Sun, 04 Nov 2007 23:43:29 -0800
To: <flyrotary@lancaironline.net>
Hi Bobby;
I have seen several turbo "detonation danger" charts over the years.  Heck if I can find any of them now.
Some searching should turn one up.
Detonation also depends on engine load - ask Lynn about NA detonation at idle speeds.

Here is a link to a calculator:
    http://www.turbofast.com.au/javacalc.html
How to avoid detonation:
    http://www.misterfixit.com/deton.htm

According to most information, 3mm apex seals will not save you from detonation in a wankel,
at best something else in the chain will break.
If you insist on running without an intercooler you better have knock sensors with a fuel cut defender or the like.
You might also look into methanol, ethanol, water injection to cool the intake charge.
The wankel has a lot of positives, survival with detonation is not one of them.

Good Luck
Cary

Bobby,
I know your planning only normalizing with the Turbo, but my concern with the 10:1 high compression rotors is that you might get into detonation - especially without an intercooler.
Then again I'm no expert, that why I would like to know the safe boost level as well.
I recommended the 3mm apex seals because of my concerns of detonation, not so much the loss of hp.
George ( down under)
George,
 
Mazfix and Mazsport are both boosting to 280hp at the wheels. http://mazfix.com.au/perfproducts/rx8_upgrades.html.  Pettit Racing is seeing 270+ with 5-8#'s  http://www.pettitracing.com/rx8/index.htm  My goal has always been to match the IO540 at 8000ft and have a much lighter plane with new engine. No doubt I will be giving up some HP without the intercooler. One percent for every 10 degrees I think. If my cooling ducts and exit area work as planned I may add an intercooler. The goal now is to get the engine started and flying by summer.
 
 
Bobby
RV10


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of George Lendich
Sent: Thursday, November 01, 2007 3:41 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: MAP port location \

Bobby,
I would be interested to see what boost is safe also. You might consider an intercooler!
I assume you are using it on a RX8 engine( i.e. 10:1 ), if so, you could always consider going to 3mm apex seals, if you feel it would be safer.
George (down under)
 
Not much to tell Rob. It's an Eaton M62 4th gen. http://www.capa.com.au/eaton_mp62_4th.htm  My notes show the weight at 25 lbs but I am not sure if that included mounting brackets.  If everything goes as planned I should be able to fire it up in January. The plan is to use it for normalization or 1-2 psi of boost if the discharge temps are not to high. It has a 1" internal bypass that provides a intake air path around the screws so it is yet to be seen what effect this will have on temps. 
 
Does anyone have any real data as to maximum safe intake temps with 10:1 rotors and 2mm seals?  
 
Bobby
 
 
 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Rob
Sent: Thursday, November 01, 2007 9:39 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: MAP port location \

Bobby
Tell us a little about your supercharger. What brand? How much? How heavy? Have you run it yet?
Thanks.
Robert
20B in a BD4
 
Robert Bollinger
FM1099 MUM
Fairfield, IA 52557
rob@mum.edu 
Home (641)472-7000ex2068
Cell     (641)919-3213
----- Original Message -----
Sent: Monday, October 29, 2007 5:09 PM
Subject: [FlyRotary] Re: MAP port location \

Looks like the consensus is to place the MAP ports away from the runners. I will try the discharge duct of the supercharger for both MAP and the Grand Rapids EIS temperature probe. Looks like the EC2 temperature probe should not be place after the blower since it leans fuel at higher air temps. It will go after the air filter and before the throttle body.
 
Thanks,
 
Bobby
Image
apexboost.jpg
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