[CraigB]

Ok Einstein, you know more than the rest of the pro racing industry

 

[tw2005]

.....................then your intentions are really more just argumentative.

That's the basis of science. The best theories are tested by alternate proposition and argument. On that, they stand or fall. Consequently, many of us have abandoned the notion of a flat earth . 

".... Thinner exhaust gas, improves exhaust gas velocity inside your exhaust system. ."

Crap. The mass of the gas is the same hot or cold. 

"The temperature of a gas is a measure of the average translational kinetic energy of the molecules. In a hot gas, the molecules move faster than in a cold gas; the mass remains the same, but the kinetic energy, and hence the temperature, is greater because of the increased velocity of the molecules. " ( NASA)

The increased molecular velocity is the reason for the increased gas viscosity that inhibits flow. (See first link)

I'm out again 

Density and Mass are not the same terminology.

Thinner = less dense, The mass of the gas molecules will be the same , yes.

Density is all about mass per volume and a less dense object will accelerate easier or require less force than a more dense object



Oh, I'm out too, waiting for this goddam red flag to be lifted at Sandown. I think density had something to do with this as well!

[nzenigma]

Quick in again then out.

We can all agree that heated air/fuel mix reduces hp. Therefore, the exhaust lagging is appropriate on a performance motor that is going to cook the engine compartment. No argument.

But the spin goes further, claiming :  " This creates a scavenging effect that pulls intake gases through the system quicker, which helps to lower intake temperatures, creating more power".  This must apply to any car.

If it is factual, car companies could achieve greater power and economy cheaply by a dip and 'lag' of whole exhaust systems during manufacture. Also they would not need to fit under body heat shields.

[CraigB]

Manufacturers wont do it due to cost, as far as I know the under body heat shields as you call them are for aerodynamics and to protect the engine bay from road grime.

I got that mixed up, I'm referring to the plastic under body shields

[nzenigma]

Manufacturers wont do it due to cost, ...

I'm not a bean counter in car company, so I accept your wisdom.
Although I would have thought Mercedes, BMW et al. would have something to spare.
I also cannot find any after market exhaust systems, even for high end trucks, that do anything other than make free flow systems.

[CraigB]

Some of the more expensive car makers will ceramic coat their headers but it's still not as effective as using the wrap but manufacturers won't use wrap as it only lasts 3 to 4 years before needing replacement and if not maintained properly can unravel and become hazardous.

Also wrapping doesn't look very appealing so that would obviously be a factor as well.

Even in racing if you want the ceramic coating and the wrap you have to do it aftermarket.

[Lakes]

There's the basic principle of keeping your incoming air as cold as possible, since cold air is dense air. The denser the air, the more oxygen you're feeding the combustion process. By concentrating the heat within the exhaust manifold and minimising the heat leakage using the wrap, you're giving the inlet manifold and surroung intake path the best chance at a colder environment.

but your hy crdi puts hot exhaust gas's into your intake gonz, don't worry both mine did too and they performed good.

I used that wrap on my Harley once but I never saw 1 mph entrap speed gain or 1 tenth in time quicker it was the same with or without. but I tried a different set of pipes, on same bike same day and saw a 12mph trap speed gain and 5 tenths quicker time. but that bandage only works for mummy's.
on a car might help in keeping under Bonet temps down but if that helps or not I have not tested with and without. I don't think it's is worth wrapping up your exhaust system that you can get to easy on the i30.

[Dazzler]

One of my mates is getting a very good crowd in Longford Tasmania to ceramic coat his custom headers/extractors inside and out on his supped up Skoda Octavia. 

[CraigB]

One of my mates is getting a very good crowd in Longford Tasmania to ceramic coat his custom headers/extractors inside and out on his supped up Skoda Octavia. 

Thinking back I wish I'd had done mine too though costs were blowing out with the modifications I had done so I skipped it

[Dazzler]

One of my mates is getting a very good crowd in Longford Tasmania to ceramic coat his custom headers/extractors inside and out on his supped up Skoda Octavia. 

Thinking back I wish I'd had done mine too though costs were blowing out with the modifications I had done so I skipped it

Not sure what it's costing because he's getting several things done and some for a mate as well. Was expecting the lot to be over $1000 though.

He used Mathew Smith Mechanical repairs 41 High street Longford Tasmania if anyone in tassie needs that sort of work done. I know this because I went up with him for a ride.

[CraigB]

I have a coating/plating workshop two minutes up the road next to the classic bike restorers, he would have charged about $300 for my short headers.

[nzenigma]

I used that wrap on my Harley once but I never saw 1 mph entrap speed gain or 1 tenth in time quicker it was the same with or without. but I tried a different set of pipes, on same bike same day and saw a 12mph trap speed gain and 5 tenths quicker time.

  Where have you been Lakes.  MATE! 

  that bandage only works for mummy's.

 

[Lakes]

I used that wrap on my Harley once but I never saw 1 mph entrap speed gain or 1 tenth in time quicker it was the same with or without. but I tried a different set of pipes, on same bike same day and saw a 12mph trap speed gain and 5 tenths quicker time.

  Where have you been Lakes.  MATE! 

  that bandage only works for mummy's.

 

still here m8
did a 41k pushy ride in the bush yesterday, bit easier on new bike but have to still peddle over 25kph as I like it up the front I peddle a lot!
cheers, how is the bow sports car going

[nzenigma]

  She's still undercover. Really hard to find a good 2.8L replacement motor. They came out with bigger M3 motor in 2001-2 so looking for any Bimmer writeoff with that in it. Will be a fun motor, loom and ?? ?? change over.
Stay fit pal 

[Dazzler]

She's still undercover. Really hard to find a good 2.8L replacement motor. They came out with bigger M3 motor in 2001-2 so looking for any Bimmer writeoff with that in it. Will be a fun motor, loom and ?? ?? change over.
Stay fit pal 

Hope she doesn't grow any more mold! 

[nzenigma]

She's becoming vintage. No problems. We expect to see all sorts of things growing on the veterans. 

[Dazzler]

I've been checking (mine's not growing)

[The Gonz]

The only time I had direct experience with exhaust wrap was when I had a dicky alternator and I was advised to try wrapping asbestos rope around the portion of pipe nearest the alternator to give it some heat shielding. The alternator was on its way out and got replaced. No power gains due to that lovely healthy asbestos in my engine bay. Those were the days!

[Dazzler]

Yeah, I shudder to think how much Asbestos laced building material I handled in my younger years! 

[nzenigma]

Yep, Same Same.
In the building industry, half the workers said it was as harmless as smoking, because they were still alive.
And again, they did both so that was the best proof