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Intercooler

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rlborger(at)mac.com
Guest

Posted: Thu Mar 09, 2006 4:31 am Post subject: Intercooler

Gottfried,



With your permission, I will try to contact Mr. Schruf at Bell Intercooler on your behalf.  Let me know if you so desire.



If there is anyone else out there in Rotax 914 Land who is interested in an intercooler for their machine, please let me know.  Perhaps we can work out a deal with multiple orders.



Please be sure to include my personal e-mail in the address as I only receive the summary digest, not the running e-mails.



For those interested, I will post more detailed pics of the intercooler kit on my builder web site this weekend. And will scan the intercooler instructions and post them as well.



Good building and great flying,

Bob Borger

Gilles.Thesee(at)ac-greno
Guest

Posted: Thu Mar 09, 2006 4:47 am Post subject: Intercooler

 	  Quote: 	
		  

For those interested, I will post more detailed pics of the intercooler kit on my builder web site this weekend. And will scan the intercooler instructions and post them as well.



  




	


Bob, Gottfried and all,



We installed a Bell intercooler in our Rotax 914 powered MCR four seater 

project.

Gerhard Schruf proved very helpful and provided tailored caculations. 

The model is not the same as that shown on Bob's website.

We put emphasis on a clean inlet and outlet for cooling air, and are 

achieving 60-70 % efficiency. The airplane has been flying for a year, 

to our satisfaction. The performance is about the same as a Europa.

Gottfried has some additional info.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

rlborger(at)mac.com
Guest

Posted: Thu Mar 09, 2006 8:22 am Post subject: intercooler

Jerry,



Consider yourself included.



Good building and great flying,

Bob Borger

 

On Thursday, March 09, 2006, at 07:44AM, Jerry Rehn <rehn(at)rockisland.com> wrote:



 	  Quote: 	
		  Bob please include me in your list of interested. Thanks



Regards

Jerry XS914

garrys(at)tampabay.rr.com
Guest

Posted: Thu Mar 09, 2006 8:52 am Post subject: Intercooler

What are the benefits of the intercooler?  What do you get in return for 

your money, labor and weight?  Why didn't Rotax design the engine with an 

intercooler?



Garry Stout

914 Trigear.....450 hours flying

---

Horizonspace(at)aol.com
Guest

Posted: Thu Mar 09, 2006 10:50 am Post subject: intercooler

Here's another source for a 914 intercooler (not Europa) for those of you  

working on other 914 applications:

 

_http://www.creas-it.it/asi_uk/accessori.htm_ 

(http://www.creas-it.it/asi_uk/accessori.htm) 

 

Tam  Pho

Horizonspace(at)aol.com
Guest

Posted: Thu Mar 09, 2006 11:12 am Post subject: Intercooler

Garry,

 

An intercooler enhances the performance of the turbocharger.  The  turbo pump 

compresses the air thus heating it up.  An intercooler cools the  air back 

down to deliver cooler/denser air to the carburetors.  More  boost, more air, 

more HP.  Most all auto turbo applications come with  intercoolers.  Rotax 

recommend installing an intercooler and provided  specific performance specs in the 

installation manual.  Integration of an  intercooler is much like that of the 

radiator and the oil cooler in that it is  installation specific.  Except in 

an intercooler installation, flow and  pressure drop is even more critical.  

Rotax could not provide a one size  fit all accessory.

 

Hope this helps,

 

Tam  Pho

rlborger(at)mac.com
Guest

Posted: Fri Mar 10, 2006 5:07 am Post subject: Intercooler

Gary,



As the others have said, additional power is available due to a cooler, denser charge of air.  But there is another reason to add an intercooler.  That hot, compressed volume of air that comes out of the turbocharger is prone to cause detonation.  By cooling the air, you greatly reduce the chances for detonation which is always a problem with turbocharged or supercharged engines.  This is the reason I chose to add the intercooler.  



I have been told that by adding an intercooler, the 5 minute limit on max power is no longer necessary.  That limit was imposed to ensure the engine never went into detonation.  With the intercooler, one can use full power continuously.  Please understand that this is hearsay information and I have not proven or tested it.  Perhaps others more experienced in the area can comment.



Good building and great flying,

Bob Borger

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Mar 10, 2006 7:43 am Post subject: Intercooler

Bob and all,



 	  Quote: 	
		  As the others have said, additional power is available due to a cooler, denser charge of air.  But there is another reason to add an intercooler.  That hot, compressed volume of air that comes out of the turbocharger is prone to cause detonation.  By cooling the air, you greatly reduce the chances for detonation which is always a problem with turbocharged or supercharged engines.  This is the reason I chose to add the intercooler. 

  



That is also the reason we went the intercooler way.
	




 	  Quote: 	
		  I have been told that by adding an intercooler, the 5 minute limit on max power is no longer necessary.  That limit was imposed to ensure the engine never went into detonation.  With the intercooler, one can use full power continuously.  Please understand that this is hearsay information and I have not proven or tested it.  Perhaps others more experienced in the area can comment.



  



I would be wary about that one, except if it came direct from the Rotax 
	


development team.

Remember that with cooler charge temperatures, the engine delivers more 

power than usual. If you use the same MP than non-intercooled, you are 

asking more from your engine, not to mention higher and longer 39' 

operation than recommended.

Note that Lycoming advises to use lower MP settings when intercooled for 

that reasons.

The engine is less prone to detonation, but this does not justify asking 

more than intended from it.



Besides, it is indeed a draggy airframe, that necessitates more than 5 

minute takeoff power !



We chose to use the normal power settings with our intercooler, but I 

retard the throttle to 100% as soon as I'm airborne. Our field has a 

2000 ft grass strip, and we have ample room to operate at full weight.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

acrojim(at)cfl.rr.com
Guest

Posted: Fri Mar 10, 2006 3:30 pm Post subject: Intercooler

I have been following this thread on intercooler's and I will add a couple if things.



It goes without saying that the turbo, compresses air, and when you compress air you get heat.



I have an early maintenance manual for my 914. In the section on the turbo, it addresses the issue of the temperature probe that is installed in the "air box" It is there to measure the inlet air temperature in the air box just before the air goes to the carb's. The onset of detonation occurs at approximately 165 degrees F. air box temperature, on the 914 ,due to the compression ratio of 9 to 1. When the temperature probe registers

165 degrees F  a command is then sent to the servo to open the wastgate, which lowers the temperature going into the air box, which prevents detonation... You normally will only get this high temp on take off with full boost and 5800 RPM on a very hot day.

The intercooler simply lowers the inlet air temperature to a point where detonation does not occur. Here in Florida, in the summer time its very easy to reach the 165 degrees temperature, on take off with full boost, without an intercooler.



I feel that of you exceed the 5 minute limit, then you will be thermal stressing the engine..



Jim Brown



Robert Borger wrote:



 	  Quote: 	
		   



 Gary,



 As the others have said, additional power is available due to a cooler, denser charge of air.  But there is another reason to add an intercooler.  That hot, compressed volume of air that comes out of the turbocharger is prone to cause detonation.  By cooling the air, you greatly reduce the chances for detonation which is always a problem with turbocharged or supercharged engines.  This is the reason I chose to add the intercooler.



 I have been told that by adding an intercooler, the 5 minute limit on max power is no longer necessary.  That limit was imposed to ensure the engine never went into detonation.  With the intercooler, one can use full power continuously.  Please understand that this is hearsay information and I have not proven or tested it.  Perhaps others more experienced in the area can comment.



 Good building and great flying,

 Bob Borger

hansjd(at)online.no
Guest

Posted: Sat Mar 11, 2006 4:13 am Post subject: Intercooler

Hi all.



Interesting thought - to get more performance out of the 914. But since 

carburettor icing is a "no-problem" - due to the heated air from the 

compressor, may not cool air from an intercooler  introduce this problem?



In other words enforcing just another mod: - carb heat?? Which again spells 

more weight, etc., etc.



Just my thought.



Cheers

Hans

Gilles.Thesee(at)ac-greno
Guest

Posted: Sat Mar 11, 2006 8:19 am Post subject: Intercooler

Hans and all,



 	  Quote: 	
		  Interesting thought - to get more performance out of the 914. But since 

carburettor icing is a "no-problem" - due to the heated air from the 

compressor, may not cool air from an intercooler  introduce this problem?

  



The 914 carbs run pretty warm in the supercharger environment. If by 
	


chance air temperature goes so low as to be in the icing range, remember 

that it's not the air that ices up, but the carb butterfly, etc...

Also, there is no such thing as a 100% efficiency intercooler 

installation, so air is still rather warm in the airbox.



You may ask, what if the carbs are so warm that vapor lock is likely ?

Now there's a good question...



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

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