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Discussion Starter · #1 ·
Whats ur guy's take on this?

Hotter air flows better and faster than colder air (PV=nRT remember from physics!), so by wrapping the pipe the heat stays in the pipe and does not get dumped to the engine. This helps reduce engine heat and also helps the exhaust flow faster. You can get the fiberglass wrap from Summit Racing for $25.00. If you do this you will also have to spray it with a hi temp ceramic coating that you can get at Autozone for $5.00. You can also send the pipe to Jet Hot to have it coated. It cost about $70.00 to have this done. This is only an option and does not have to be done.
 

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But the difference in temperature between the manifold and the downpipe is what helps spool up the turbo, the more heat you trap in the downpipe the smaller the difference in temperature.
 

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Discussion Starter · #3 ·
SAY WHAT!!!!!

I dunno about that but my first experience with using heat shield and not using them was a very noticable difference on spool up time.

Running without the o2 housing heatshield and the CHRA heatshield vs running with them made me a believer that you need those things in a real bad way, way much more repsonce running with all the stock heatshields vs not.
 

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charlie bro get it u dont know what your missin.... warp it all the way past the rear motor mount.
biggest fukin improvement on coooilin youll see. oil pan will be cooler,tranny will be cooler man u can race that **** all fuukin day an grab the downpipe right after an watch... i say buy it please.

50ft roll
 

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Discussion Starter · #6 ·
Yeah i dont visit that forum much cuzz theres a bunch of incorrectness being pass around there = monkey logic.

Anyways if you dont know they sell exhaust turbine wraps made outa some high grade expensize ass **** that fit like a glove for around ~$700, I wish I could find the website but I believe KART and INDY use these wraps to improve effiecieny by a substantial amount............so if KART and INDY use them its for a good reason u cant bet on that plus the real life experience i felt by running the car on the freeway with and without heatshields lets me know by trapping the heat in the turbine makes for a more efficent turbo so the better job u can do at keeping the heat in teh turbine the better.............same should hold true for the rest on the exhaust system since hotter air flows faster than cooler air.
 

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If you wrap the turbine section you can improve the efficiency but if the benefits of wrapping the whole downpipe, in those examples you cited, it is probably because the reduction in heat far outweighs the gains from a few points in effiency in the turbo.
 

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Discussion Starter · #8 ·
I dunno about all that ^^^^^ i have never wraped my own downpipe yet but im 99.9% positive it'll make a hella difference. Hotter the exhaust the lessor the resistance to flow = a good thang.
 

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Discussion Starter · #9 ·
HkSBlueBird4u said:
charlie bro get it u dont know what your missin.... warp it all the way past the rear motor mount.
biggest fukin improvement on coooilin youll see. oil pan will be cooler,tranny will be cooler man u can race that **** all fuukin day an grab the downpipe right after an watch... i say buy it please.

50ft roll
Thanks for confirming my thoughts, dont trip my downpipe is as good as wraped...lol
 

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QUESTION:

What about people who wrap up there downpipes to keep heat in and the exhaust gases hotter after the turbo? The hotter gases travel faster right, and that decreases pressure (good)? Or, the higher retained heat keeps the gases hot and the pressure stays higher and that would lower the pressure differential (bad)?

ANSWER:

Welcome to the real world.

Both are legit ways of examining the problem, and either scenario is possible, depending of the flow capacity of the exhaust system. If it is capable of flowing the exhaust, then the retained heat will service to increase velocity, lower the pressure seen at the outlet, increase the pressure differential, and increase power. If, however, the system cannot flow the gas produced, then the retained heat only serves to increase the pressure seen by the outlet, decrease the pressure differential, and reduce power.

Theory is a wonderful thing. It lets you gain an understanding of what's going on, allows you to ask meaningful questions, and leads you to try things in an intelligent manner. Ultimately though, when you start talking about specific applications, there is no substitute for trying it out and testing it.
 

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Discussion Starter · #12 ·
Thats to much to read................just tell me what ur trying to say here.

1) Thermowrap sucks and u should never use it because u'll lose horsepower

2) or that exact opposite
 

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James said:
QUESTION:

What about people who wrap up there downpipes to keep heat in and the exhaust gases hotter after the turbo? The hotter gases travel faster right, and that decreases pressure (good)? Or, the higher retained heat keeps the gases hot and the pressure stays higher and that would lower the pressure differential (bad)?

ANSWER:

Welcome to the real world.

Both are legit ways of examining the problem, and either scenario is possible, depending of the flow capacity of the exhaust system. If it is capable of flowing the exhaust, then the retained heat will service to increase velocity, lower the pressure seen at the outlet, increase the pressure differential, and increase power. If, however, the system cannot flow the gas produced, then the retained heat only serves to increase the pressure seen by the outlet, decrease the pressure differential, and reduce power.

Theory is a wonderful thing. It lets you gain an understanding of what's going on, allows you to ask meaningful questions, and leads you to try things in an intelligent manner. Ultimately though, when you start talking about specific applications, there is no substitute for trying it out and testing it.
Your question is exactly answered in his text.
 

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Discussion Starter · #14 ·
James said:
QUESTION:

What about people who wrap up there downpipes to keep heat in and the exhaust gases hotter after the turbo? The hotter gases travel faster right, and that decreases pressure (good)? Or, the higher retained heat keeps the gases hot and the pressure stays higher and that would lower the pressure differential (bad)?

ANSWER:

Welcome to the real world.

Both are legit ways of examining the problem, and either scenario is possible, depending of the flow capacity of the exhaust system. If it is capable of flowing the exhaust, then the retained heat will service to increase velocity, lower the pressure seen at the outlet, increase the pressure differential, and increase power. If, however, the system cannot flow the gas produced, then the retained heat only serves to increase the pressure seen by the outlet, decrease the pressure differential, and reduce power.

Theory is a wonderful thing. It lets you gain an understanding of what's going on, allows you to ask meaningful questions, and leads you to try things in an intelligent manner. Ultimately though, when you start talking about specific applications, there is no substitute for trying it out and testing it.

Thanks for posting that...............pretty wierd but cool ****. So if ur exhaust is sufficient enought to flow the gases produced heat wrapping will not hurt infact it probably help out..............but on the other hand say you have a 2 inch exhaust system which cannot flow enough of the exhaust gases which is probably really hot as **** allready then u thermowrap it u make it that much worse as u'll further lesson the pressure differential. Makes sense to me
 

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Heh... unfortunately, as I learned in grad. fluids class, it depends....
 

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When i used the thermo wrap on my downpipe from summit, i swear i noticed a difference the car seemed to be a little more responsive and the temps seem to have went down, i would say if you have an aftermarket 2.5-3in exhaust go for it the 50ft rolls form summit are pretty cheap. Just dont try to wrap the flex section of corse, dont ask me how i know.LOL

Later,Jon
 

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My downpipe is wrapped. I'm not sure if it made any difference in power or response, but keeping the heat in the downpipe helps the cat to light off sooner and makes it more efficient. This was the primary reason I wrapped mine.
 

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Go for the Swain Coating on your downpipe. It will cost you under $100 and will protect the welds from rusting.

Do not forget that temperature differentials must be measured within the substant medium and have the greatest impact at points of pressure change.

In other words, concern for temp differences should really only matter at, say, CAT entry and muffler tip.
 

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Discussion Starter · #19 ·
iNGEN said:
Go for the Swain Coating on your downpipe. It will cost you under $100 and will protect the welds from rusting.

Do not forget that temperature differentials must be measured within the substant medium and have the greatest impact at points of pressure change.

In other words, concern for temp differences should really only matter at, say, CAT entry and muffler tip.

So say you could keep the temps from the turbine threw the downpipe all the way to the cat the same (ofcourse this wouldn;t happen but u could make it closer with thermowrap), here you have 2 benefits I see if i understand correctly.

1) You stop alot of the radiant heat that comes off the down pipe to a minumum.
2) You keep the exhaust flowing faster because it stay hotter atleast part way threw the system.

*1 more thing, just curious

The actual outlet in the o2 sensor houseing it approx ~2 1/4 inch...........wouldnt there be a big pressure change there if u have a 3 inch downpipe? What sorta impact would that have versus a 2 1/4 inch dp but say both systems have 2.5 - 3 inch cat backs.


P.S. I just wanna understand how the whole tempature diffrentials thing place a part.
 

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Discussion Starter · #20 ·
James said:
QUESTION:

What about people who wrap up there downpipes to keep heat in and the exhaust gases hotter after the turbo? The hotter gases travel faster right, and that decreases pressure (good)? Or, the higher retained heat keeps the gases hot and the pressure stays higher and that would lower the pressure differential (bad)?

ANSWER:

Welcome to the real world.

Both are legit ways of examining the problem, and either scenario is possible, depending of the flow capacity of the exhaust system. If it is capable of flowing the exhaust, then the retained heat will service to increase velocity, lower the pressure seen at the outlet, increase the pressure differential, and increase power. If, however, the system cannot flow the gas produced, then the retained heat only serves to increase the pressure seen by the outlet, decrease the pressure differential, and reduce power.

Theory is a wonderful thing. It lets you gain an understanding of what's going on, allows you to ask meaningful questions, and leads you to try things in an intelligent manner. Ultimately though, when you start talking about specific applications, there is no substitute for trying it out and testing it.
Whos say that after the turbine outlet (o2 sensor housing) that, thats the end of the exhaust system, it is a mere extension of the turbo I would think..................so where and when does this "pressure diffrential" need to take place? ..............I'd say at the muffler tip.

All in all what I gather is if ur dp is big enough to flow the gases allready, then by wrapping it u help increase the velocity which is an added bonus.

and

if your dp is to small to flow the gases allready, then by wrapping it u further make it less efficient.
 
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