Easily tested

I you want to try an experiement with it, seems it would be easy to gather data on your stock system first. Then try an aluminized wrap, much cheeper to buy some from a local race car parts supplier. Then compare your data to see what difference it made.

Like; http://www.pegasusautoracing.com/productselection.asp?Product=1828 or http://www.pegasusautoracing.com/productdetails.asp?RecID=395

With the airflow thru the area I doubt the intakes absorb any significant heat radiated by the exhaust pipes, with most of the heat transferred by direct contact with the oil. But hey, your experiment might prove otherwise. :)
 
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IIRC, Lyc claimed 2% hp from chrome tubes, heli stuff.

Chrome reflects the heat..............
 
Kent Paser Did It

Just as a point of reference, Kent Paser of Speed with Economy fame insulated his intake tubes. Doesn't mean that it works of course. He states on page 56 of his book that insulating the tubes allowed him to run 50-75 degrees leaner before the engine got rough.

I think that insulating the exhaust makes a lot of sense, mine are jet hot coated inside and out, which reduces radiant heat from the exhaust 50+%. The increased heat held within the exhaust is supposed to increase power due to better scavenging, about 1.5% or so. The downside is that once you have the exhaust coated, it can no longer be welded. You could do the same coating on the intake tubes as well.

Hans
 
Being the guy who peddles these things, here's my experience:

1)I initially installed these to keep the exhaust heat from damaging the rubber intake hoses. The heat reflected away from the rubber parts absolutely works as intended here. The intake hoses were being roasted on my plane beforehand. They were replaced then I installed the heat shielding, and the intake hoses still look great several years later.

2) My injectors were balanced (GAMIfied per Don Rivera's instructions) before the heat shielding. After installing the heat shielding, the injector balance changed and had to be redone. I interpret that as possible heat rejection.

As stated in the product description on the web store, my opinion is that 1400F exhaust heat trumps 200F oil heat when it comes to which one affects the induction air temps the most. I don't see much chance of "cooling" the induction air by leaving the intake tubes bare... not with up to 350F air blowing past them on all sides, and 1400F exhaust pipes an inch away.

Obviously all of this is quite subjective. YMMV.

I am pleased with these items on my airplane and have no intention of removing them. They seem to do what I intended.

I would like to clarify one thing though, if we were motivated to "move dollars out " of our customers pockets we'd find a different business, one where we didn't have to worry about offending hundreds of RVers whom we consider to be our friends. We're not in this for the money. Mostly our tiny little business started by chance, grew by luck, and has absolutely no chance of ever threatening Aircraft Spruce, Wicks, Vans, etc.... We like it that way.
 
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Wouldn't it be relatively easy to stick a temp probe in the intake tube and get objective data?
 
I put some heat insulating tape from ACS on my intake tubes in order to try to balance the EGTs with my Carb set up. It did help a little, but I can no longer remember the exact differences that I saw. If I recall correctly, it changed hotest to lowest sequence. It didn't occur to me there may be improved HP, this would be much harder to measure.
 
Induction Tube Temp.

I did this test last summer. On a IO-540 @ 2500 RPM, 178 degrees oil temp, ambient air temp 76 degrees, temp probe in the induction tube located 4.00? before the intake valve. The temperature rise in the induction tube was less than a 1-1/2 degrees (actual reading was fluctuating between .7 and 1.3). I have also been doing R&D on induction & exhaust system mods. With and average of 4+ mph speed increased @ WOT on a RV4. Soon G3i?s aircraft engine dyno facility will be operational for a more controlled and accurate data information on performance mods. claims.

Thomas S.
www.g3ignition.com
See you there, KOSH. Booth #1148
 
G3i Ignition said:
I did this test last summer. On a IO-540 @ 2500 RPM, 178 degrees oil temp, ambient air temp 76 degrees, temp probe in the induction tube located 4.00” before the intake valve. The temperature rise in the induction tube was less than a 1-1/2 degrees (actual reading was fluctuating between .7 and 1.3). I have also been doing R&D on induction & exhaust system mods. With and average of 4+ mph speed increased @ WOT on a RV4. Soon G3i’s aircraft engine dyno facility will be operational for a more controlled and accurate data information on performance mods. claims.

Thomas S.
www.g3ignition.com
See you there, KOSH. Booth #1148
Click to expand...

Tom, What temps were you seeing in the induction tubes with an ambient of 76 degrees? Also, cyl #3 & #4 have a hot exhaust pipe on either side of the intake tube so I would guess they would be more effected by the heat than cyl #1 &#2.
 
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RV7AV8R said:
Tom, What temps were you seeing in the induction tubes with an ambient of 76 degrees? Also, cyl #3 & #4 have a hot exhaust pipe on either side of the intake tube so I would guess they would be more effected by the heat than cyl #1 .
Click to expand...

John,
The intake air goes through so quickly; there is not much heat transfer. However, you bring up a good point, next time I run an engine with the cowling off, I will infrared the induction tube outer wall and make comparisons.
With the ambient temp of 76 degrees the reading was 77-78. (WOT static thrust pulls, with cowling off.). The temp. Reading was taken from #6 induction tube, thermal couple inserted .625" from tube wall. This test was to establish a baseline temperature. I was R&D testing (cc's of volume & different pump pressures) of a water injection system I was playing around with.
Thomas S.
 
Tom,

Where was your OAT probe located? Were both the intake and OAT probes reading the same before engine start?

I had to move my OAT probe on my Rocket to outboard on the wing. Any place behind the engine read much warmer than ambient, as much as 10F. Hot engine influencing the temps I suppose. So, I'm suspicious of any fuselage mounted OAT probes unless proven unaffected. (These temps take into account ram air temp rise due to speed also. That is not the effect I'm referring to here.)

I agree that any temp rise in the intake tubes can't be very large due to rapid air flow, but I assumed that there is some rise. Otherwise there would be no need for expensive cold air induction systems!

Like I said previously, I initially installed these items to keep the rubber parts from roasting. That I saw a injector balance change prompted me to also offer this as a possible HP increase.

YMMV, experiments will tell! Some engines may benefit, some might just look cool, some installations might just be dead weight!

Fly safely!
 
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Just went by OAT (temp probe not located on the aircraft) @ the run-up area by the hanger.
Quote, ?Otherwise there would be no need for expensive cold air induction systems?
Hate to burst bubbles here, on a cold air induction system; the power increase is not from a cold intake charge. It is based upon the Helmholtz equation used in resonant and momentum tuning (speed of sound). In short intake runner length and plenum size. Bottom line is that the stock aircraft intake system can be improved. Why they called it a cold air system?? Probably easyier than explaining momentum tuning.
It?s all fun.
Thomas S.
G3i
 
For those who are still interested in this thread, I just got off the phone with Larry Vetterman, who had left me a message to call him regarding this thread.

Many of you already know who Larry is. If you don't, you will when it comes time to buy your exhaust system. Larry has built thousands of our RV exhaust systems and has been around RVs as long as anyone.

My head is spinning from all the data Larry threw at me but in a nutshell it is this: insulating the intake pipes absolutely helps. He called it a "poor man's supercharger" and said he had gobs of real world data obtained from testing on his RV-4 and other aircraft.

Larry said that he was heading to vacation today. Hopefully, he can chime in with additional comments or clarification when he gets back.

Until then, I'll stand by my personal experience that the intake insulation prevents damage to the rubber components of the intake tube and on my airplane it made a difference. YMMV.

As Thomas S. said above "It's all fun."

Keep experimenting!
 
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