355 Inner CV boot deterioration, swelling, deformation and cracking problem? .. Nope!

Negative

Dave Helms never did this important update for the 355

 

Great

 

And stop fires from leaking hose and unions

 

I have to ask, why stainless steel? As a radiation shield it looses effectiveness as it weathers. Aluminum tends to hold up better as it weathers (or oxidizes).

 

When will these be available at Ricambi ?

 

damn those look awesome!!

 

They're here, and ready for shipment today:

Ferrari Parts : GS355CV F355 CV BOOT SHIELD SET : Ricambi America

The price includes 2x shields, hardware, and an installation guide. Thank you Gothspeed!!

 

Daniel

Great ...i really need a set but 128usd shipping to Spain?

Is there no reasonable way to ship?

 

It would be easier to send a PM or email instead of posting in this thread. I have sent a quote with shipping to your direct email.

 

Perfect timing! Ordered a pair this morning.

 

Ordered. Thanks. Don't forget fchat10 discount code.

 

Are these shields for use in addition to the OEM or as a complete replacement?, It looks like you can install the OEM shields on top of gothspeed shiels.

 

I like the idea but I think I'll wait for some results from field tests. What's that going to take, 3, 4, 5 years?

 

Good idea. We need to know for sure if heat from nearby exhaust manifolds ruins the rubber, or maybe it's something else, like mice that get in there when the car's in the barn.

 

My inners are way worse than my outers - even though they were replaced at the same time a few years ago. Not only do they have contend with the headers they're even closer to the hotter catalytics. Ferrari didn't put heat shields there for no reason, unless they're actually poorly designed mouse traps.

 

I have no doubt that it is the heat. My concerns are the effectiveness of SS as a heat shield, the lack of an inner insulation material and the confinement of the CV boot which is now surrounded by the shield. Aluminum is much more effective as a radiation shield than SS once aged and weathered, by about a factor of 5. You may recall that earlier in this thread I question the use of SS and also suggested that the inner surface be coated with a low emissivity ceramic.

 

You should make some. That would be really helpful.

 

The ability of aluminum to conduct heat would actually make it a poor choice as a heat shield ...why would you want to use a heat conducter as a shield? Wouldn't you want an insulator? Something that isolates heat from the source? And why worry about aged and weathered stainless steel on your car? If your stainless is corroded, you have much more serious problems to attend to.

I put stainless heat shields on my 66 Corvette exhaust and it really helped to keep the floorboards cooler. My feet are no longer melting and with these shields i can't help to think that my CV boots won't either.

 

Conduction isn't the issue. Yes, AL has higher conduction than SS but what does that tell you? Only that the inside surface temperature will be closer to the outside surface temperature. These shields are thin and regardless of whether SS or AL, there will be little temp difference across the material. Conduction is only an issue when the material has significant thickness or when there are order of magnitude differences in conduction (like steel and ceramics).

What controls the effectiveness of the ability limit radiative heat transfer is its emissivity. You can stick just about any material between a source and receiver of radiation and it will cut down the radiative heat transfer. But the lower emissivity, the more effective it will be. I'm sure you have heard of low e windows to keep you house cooler in summer and warmer in winter? They are low e because they have a low emissivity shield between the two plains of glass.

Looking at SS emissivity values for highly polished SS it is about 0.045, for plain old 301 SS about 0.6 and for weathered SS about 0.88.

Looking at AL, highly polished is about 0.045, a commercial sheet of AL about 0.09 and oxidized AL is about 0.25. So even oxidized AL is a better shield than off the role 301 SS.

As for insulating, yes, it would be productive to keep the inner surface temperature cooler if possible. This is why I suggested the inner surface be coated with a low emissivity ceramic. This would keep the inner surface cooler and the low emissivity would further limit the heat radiated to the boot.

But ultimately how much heat transfer to the boot is only 1/2 the story in determining how hot the boot will get. In the absence of some form of cooling the boot would heat without limit regardless of how little or how much heat was transferred. All that would differ is how long it would take. Cooling is the issue. There is an equilibrium temperature that will be reached when the rate of heating is equal to the rate of cooling. The boots are cooled primarily through convection by the air circulation around them. Reduce the air flow around the boots and there is the potential for them to end up at a higher temperature even with reduced radiative heat transfer. It seems to me that with the boot completely enclosed there is this possibility.

I apologize for being so critical. I do hope that in the end I am proven wrong, but as I stated, I'll wait for some longer term field tests for conclusive evidence.

In the mean time, I would like to show you all the approach I took to the problem after installing new boots on my car a couple of years ago. I simple cut a piece of sheet aluminum the same shape of the oem shields and mounted it over the oem shields. Thus I have the added benefit of two layers of heat shields with a low e outer shield and retain the insulating properties of the oem shields and the open air circulation of the original design. After 2 years I see no deformation of the new boots.
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I'm going to give them a shot, certainly should deal with the radiant heat better than the "floppy" shields now present. This is definitely something that should be considered since I changed out my boots earlier this year after seeing grease flung all over after the boots were shriveled and cracked after suffering heat damage from the cats and exhaust.

Is it me, or does the design look tuff, like A part designed in the laboratory of a mad scientist....