(Old Stories time)  In 1981 I bought an RX-7, drove it for a year, and had it turboed at a speed shop in L.A.  No intercoolers for cars in those days.  The way they got around detonation was with water injection.  A cheap windshield washer container and pump, and a vacuum sensor at the intake.  With adjustable boost, it ran great!  Sea level was the most dangerous, had to watch it close there, but going over Sherwin and Donners summits (6,000 ft. +) I could dial in almost 9-10 lbs, and that sucker screamed.  Put probably 50K miles on it before I sold it, and never had any trouble.  So, all, would water injection be a good backup for hot days?  I heard that some of the early turbocharged engines during WWII used it, so why haven't we tried it?

Greg Ward

Lancair Legacy 20b, STILL in progress

----- Original Message -----

From: hoursaway1@comcast.net

To: Rotary motors in aircraft

Sent: Friday, August 24, 2012 8:34 PM

Subject: [FlyRotary] Re: Check Temps on Climbout was e: [FlyRotary]Turboquestion.

See how much one can learn from one simple sentance.  Thanks all for the update.  David R. Cook  RV6A  Rotary  28hrs.

---

From: "David Leonard" <wdleonard@gmail.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Friday, August 24, 2012 8:51:21 PM
Subject: [FlyRotary] Re: Check Temps on Climbout was e: [FlyRotary]Turboquestion.

And just to belabor the point even more, turbos are less than 100% efficient.  Meaning that any extra work that went into trying to compress the air but did not, ends up as additional heat in the compressed air.  And, the turbo itself is very hot even on the compressor side, which adds even more calories.

All that being said, you CAN run small amounts of boost without an intercooler, but you have to compensate by running extra rich and or retarding the timing.  Much better in the long run to use an intercooler.

David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net

On Fri, Aug 24, 2012 at 4:42 PM, Dave Staten <david.staten@gmail.com> wrote:

Air at altitude is cooler because of low pressure. When you compress it, it heats. Intake temps can be over 250 degrees, greatly increasing the chance of detonation. Intercoolers are VERY necessary if you want to reap any benefit from the turbo. 

Dave. 

Sent from my iPhone

On Aug 23, 2012, at 17:45, hoursaway1@comcast.net wrote:

Hay Chris,  I'm not turbo savy, but do you realy need an intercooler,,,,,,,at altitude,,,,,, the air is pretty cold already, the racers on the ground need them because the air near the ground is hot, not at 6000+++ feet.  just a thought & will be watching, a turbo instead of a muffler I'm thinking may be a better choice.  David R. Cook  RV6A  Rotary Lansing MI.

---

From: "Chris Barber" <cbarber@texasattorney.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, August 22, 2012 9:49:50 PM
Subject: [FlyRotary] Re: Check Temps on Climbout was e: [FlyRotary]Turboquestion.

Yes. That is correct. The 3lb spring limits boost it is the lowest I have as I wanted to start low. 

I checked my intercooler and it is flowing well. No obstruction or leak I could find. It may be the location of the blow of valve. I will remove it and see if I get good boost

Sent from my iPhone 4

On Aug 22, 2012, at 6:30 PM, "CozyGirrrl@aol.com" <CozyGirrrl@aol.com> wrote:

Andrew, I believe the 3 lb spring he is talking about is the wastegate spring, this limits boost, the 3 lb one is the lowest boost available, as the springs get stronger the more exhaust is forced through the turbo.

Chris?

 

Chrissi & Randi

www.CozyGirrrl.com
ClickBonds 10/$7.50
CG Products, Custom Aircraft Hardware
Chairwomen, Sun-N-Fun Engine Workshop

 

In a message dated 8/22/2012 6:08:30 P.M. Central Daylight Time, andrew@martinag.com.au writes:

Chris

if your blow off valve is before the intercooler, it may just be opening too soon with that 3lb spring and allowing all your air to vent, then the engine would act as NA but with the intercooler as a added restriction. try a heavier spring.

Andrew

On Thu, Aug 23, 2012 at 6:53 AM, Chris Barber <cbarber@texasattorney.net> wrote:

Thanks Ed. I am pleased you verified my concern after my cooling skyrocketing yesterday when I went to full power.

Trying to determine where the restriction is now.

You are the best.

Sent from my iPhone 4

On Aug 22, 2012, at 4:48 PM, "Ed Anderson" <eanderson@carolina.rr.com> wrote:

> Chris, One thing to be checking on your next take off is your coolant/oil temps.  As you know take-off is the worst combination of low cooling air mass flow and max engine temperature due to WOT.
>
> You would be surprised how quickly (with the additional power you now have) you will exceed your cooling limits if not careful.  So I would be certain to check the temps at a frequent rate on your next take-off until you know how the system is going to react - hate to see you cook your engine during your first real Turbo climb out.
>
> I find for my Rv-6A that I needed to get to 120 mph IAS as quick as possible to get on the good side of the cooling curve.  So that generally meant take off - get safely above surround obstructions, then level off/reduce climb until airspeed hit 120.  Then I could resume climb with cooling gradually bring the temps down as altitude and airflow increased.  Your sweet spot airspeed would undoubtedly be different given different platform and cooling set up.
>
> Ed
>
> --------------------------------------------------
> From: "Chris Barber" <cbarber@texasattorney.net>
> Sent: Monday, August 20, 2012 9:17 PM
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Subject: [FlyRotary] Turbo question.
>
>> As I have mentioned I have had what I think are incongruent readings regarding my manifold pressure (mp)and engine rpm. It seems I am getting quite low mp as I add power to higher rpm.
>>
>> I am not well versed in this area but my thought is that as I add power, even with slight boost (currently using a 3 lb spring in my wastegate) eventually my mp should raise a bit more.
>>
>> Today I did some static test. I recorded engine RPM with the  turbo hooked up and recorded the mp at 1000 rpm increments. Then I removed the turbo plumbing from my intake and recorded the same info My results currently confuse me.
>>
>> With the turbo hooked up I am getting
>>
>> RPM.   MP inches
>> 2000 - 14.0
>> 3000 - 15.5
>> 4000 - 19.3
>> 5000 - 21.6
>> 5700 - 24.5 (topped out)
>>
>> With the turbo removed.
>>
>> 2000 - 15.8
>> 3000 - 15.3
>> 4000 - 19.7
>> 5000 - 24.8
>> 5833 - 29.8
>>
>> Is this indicative of restriction in my plumbing? Perhaps in the inter cooler? A dirty air filter? A bad pop off valve or a leak not allowing the air pressure getting to the intake. Or????
>>
>> I am uncertain what other permitters I need to check and provide. I am just starting my diagnosis in my Phase One testing. I only have 1.6 hours in the air so far. I value ya'll's direction and input.
>>
>> Heck, perhaps this is working properly but it just doesn't seem right/comfortable.
>>
>> Thanks folks.
>>
>> Chris Barber
>> Houston
>> Velocity SE
>> Rotary 13b turbo (?) :-)
>>
>>
>>
>> Sent from my iPhone 4
>> --
>> Homepage:  http://www.flyrotary.com/
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>>
>>
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>
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Regards

Andrew Martin
Martin Ag
275 Newmarracarra Rd
Moonyoonooka WA 6532

0427477144
08 99241145
andrew@martinag.com.au

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