alright, I am thinkin about going with the buschur ported/jet coated manifold (stock, exchange). But I was thinking... what is the jet coating really for? On the site it says to keep engine bay temps down... I feel that but the gaping hole over my manifold seems to do a good job of that. The only other issue that I feel is probably a factor is the heat going to the turbo... Now more heat to the turbo should mean more energy hence more power... but how much? I would think minimal. The other aspect of the heat going to the turbo would be durability of the turbo with greater inlet temps. I would think that both the manifold and turbo would be under greater thermal stresses b/c of the added heat in the system that was not allowed to radiate off of the manifold.
So is it really pretty much for looks? I know the rusty look isn't quite "in"... so is that pretty much it?

 

Thermal efficiency is needed as hot gases do hold more energy. Being that the manifold is cast iron, I dont believe failure is likely due to the heat. My worry is pieces of coating chipping off the inside of the manifold (if the inside were coated...i dont know) and coming in contact with the turbine.

These are great questions....i was thinking about this service as well.

 

The heat actually escapes faster. Heat being absorbed into the manifold just makes things hotter. Jet Hot coating and other coating have been proven for a while. I don't know about numbers, maybe someone might chime in. You don't want the heat to radiate off of the manifold. You want it to exit the engine as fast as you can.

 

hey scott....let me port your manifold...im handy with a dremel lol

 

you didnt give any real evidence though... yea, you want heat to exit, but for the turbo's sake isn't it wise to rid yourself of it before the turbo? my initial questions hold.

 

Basicly heat is energy. Having the heat go through the turbo instead of out through the manifold makes the turbo more efficient and faster spooling.

 

A cast iron manifold retains much more heat than a thinwall, tubular steel manifold, so that is one advantage. Paper-thin coatings won't change that, and amount to little more than high-temp paint that is mostly aesthetic IMO. Don't let that make or break a purchasing decision.

 

as I had initially stated, I get that, however the rewards of say... oh to be generous... 200 degrees F cannot make any noticiable difference in spool or output cfm... and if anything contributes to the intake temperature increase.

 

thanks ted ... thats my thought too... I want some evidence though.

 

the moves heat through faster, the reason you can touch your manifold 45 seconds after you turn the car.. heat is what drives the turbo, if the exhaust gases arent hot there useless too the turbo.. it will make a diff, esp under hood temps.. and it is proven to work.. also if you do it i would strongly recommened doing the inside and out... i have to send my tube header out to be done soon.. i just havent found someone close to do it yet... i know the guys at o.c.c. have a guy close buy who does it..

 

Go do it and dyno the results. You must be the first. Since no one is giving you the numbers youo are looking for

 

Yup, heat is what drives the turbine. The nozzle is where all the magic happens. Hot exhaust gas comes in, and, passing through the nozzle, trades heat for velocity, just like in a rocket. The jet of gas then impinges on the turbine blades and transfers energy (impulse) to run the compressor side. Just a guess, but the blades are probably designed for some reaction effect at the discharge, too.

Dave

 

Like I've said, I understand that more heat is more energy, however just those few hundred degrees (if that)... thats what I'm asking can they make a difference? (lets go even further to say can they make enough difference worth $125?) Because I know that temperatures and heat cycles make a large difference on metal strength over time. (turbo durability) People say that jetcoating has been proven... where's the proof? ...proven at what? keeping the engine bay temps down? There's no disputing that, I'm looking for a difference in spool or power that would offset the possible additional stresses on the rest of the exhaust. (as a side note, I wouldnt even be asking this question if I were using tubular headers, b/c I know that there is tremendous heat loss with them, however I am using cast which already soaks up a bunch of heat.) Someone show me how jetcoating is 'proven' please!

 

Do it yourself and stop asking the question over and over again. Obviously no one has any difinitive answers for you, so go do it yourself!!!!!!!!

Here read this, it is more thatn a couple hundred degrees
http://www.hpcoatings.com/import_performance.htm

 

^holy crap lolol