More HP by insulating the induction tubes?

[ao.frog]

Hi.

I'm considering installing these: http://www.flyboyaccessories.com/sto...roducts_id=269

Does anyone have experience with them? Seems like a good idea...?

[RV8RIVETER]

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/pro...p?Product=1828 or http://www.pegasusautoracing.com/pro....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.

[Mike S]

IIRC, Lyc claimed 2% hp from chrome tubes, heli stuff.

Chrome reflects the heat..............

[nucleus]

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

[vfrazier]

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.

[szicree]

Wouldn't it be relatively easy to stick a temp probe in the intake tube and get objective data?

[RV7AV8R]

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.

[G3i Ignition]

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

[RV7AV8R]

Originally Posted by G3i Ignition

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

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.

[G3i Ignition]

Originally Posted by RV7AV8R

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 .

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.