i'll chime in. if that is a quote from dave, and that picture of the lower intercooler is actually the comparision of the lower intercooler pipe to an aftermarket, dave is wrong. that stock pipe has a diameter change, which is horrible as far as head losses are concerned. you want math? get any fluid dynamics book and look up head loss or fluid resistance. you will see that diameter changes, bends, orifaces (constrictions), rough sidewalls, all effect the pressure drop (headloss). sharp bends and tight radius turns are all losses when compared to a larger radius turn (to a certain extent). both the upper and the lower intercooler pipe will decrease the head loss. also, if you have a 5 inch upper intercooler pipe it isn't going to do **** for performance if you still have that 1 inch constriction right after the turbo remember your only going to flow as much air as the tightest constriction will allow. and obviously that restriction is on the lower intercooler pipe.

and damn 03BRevo8... are you in love with buschur or what? sure he makes some great stuff, but this isn't rocket science, and there are certainly some people that can prove that the lower intercooler pipe is more important to change out. i would consider myself one of those people, and when i get around to making my own pipes, i'll inform you of the exact amount of pressure drop the stock has when compared to aftermarket. i'll do the same for the upper.

 

No ive been dealing with Dave and using his stuff on my car and friends cars since he started on the 4G63 like 13 years ago... I do not think anyone has put more into this engine over the past 10 years than Buschur.. Who has the fastest stock turbo'd non nos evo? Buschur evo's have hit 10.9 on the stock turbo... Cant do that with the stock upp

 

i never said the stock upper wasn't important to change out. i just said buschur is wrong if he said that the stock lower pipe works just fine, and people change it out just to make it look better. and i don't care if dave invented the 4G63, the lower intercooler pipe is a huge restriction, and if you want to reduce pressure loss, change it out.

simply changing out any pipes doesn't really "make" more power, it just increases the efficiency of the engine. whoever was talking about the VE of the engine was sort of right. the VE determines how much air the engine will suck in, but that is determined by your intake routing and exhaust routing among other things.

 

it is but not so for the stock turbo..

 

are you joking? if so haha. if not i demand that you return all your parts and sell your evo because clueless people don't deserve to have more mods then me.


are you an engineer? i'm going to guess your not because you don't have any idea what your talking about.

 

No i was and encryption specialist military ,and now mail man

 

Well i guess everyone has there own opinions.. let me see some Numbers and then ill beleive that the upp doesnt effect it more than the lower.. wouldn the lower be one of the first mods then?

 

i'll get you some numbers then. when i get out of work i'll make some measurements and let you know

but just for ****s and giggles until then (cause i have to make a new dash for our race car tonight, so it might be tomorrow with the numbers), go to Mc donalds and order a chocolate shake. now go get a coffee straw and a regular straw. picture these two straws as your intake pipes and you are the engine. suck as hard as you can with the coffee straw and try to get shake. it works but not to well huh. now try it with the big straw? better results huh?

ok, now to show you that lower is just as important as upper, take your big straw and pinch it at the bottom of the straw so it is half the diameter and then try sucking? much less i'm betting. and then pinch it at the top? same results at at the bottom....?

my point is, bigger is better with pipes to a certain extent. restrictions no matter where they are are bad. the lower intercooler pipe has a large restriction and removing it will make your engine breath better. this also doesn't matter which turbo your using, because you can have no turbo at all and it will still help.

 

It doesn't matter if one installs 6" diameter IC pipes. The engine will uses only as much air as allowed by its mechanical volumetric efficiency, period. Therefore, larger pipes do not automatically translate into more air.

The concept of larger, straighter pipes seems logical where basic engineering strategy is concerned. However, it's also a logical realization that it's only going to be of benefit to the degree that the existing arrangement falls short, and nothing more. In this case, that doesn't appear to be as much as some persons would like to believe. In fact, independent evaluations have indicated the difference to be small.

 

Thge lower pipe SHOULD be one of the 1st mods. Just like a 2G DSM, before you even start modding teh 1st thing to do is replace teh terrible FLAT upper IC pipe and plastic BOV that will leak after 12psi. The Evo isn't as crippled but the lower pipe is holding back...


Throttle Response
Boost Pressure
WHP
Spoolup
and of course volume.


The upper MAY add SOME whp but I doubt more then 3 WHP, it is nice to have especially with an upgraded turbo and woun't blow off as easy with T-Bolt clamps which are a must for higher PSI.

 

haha VE is determined by a number of things. one of which is intake pipes. if you have extremely restrcitive intake pipes your VE will suck. if you have a 6 inch pipe, the intake wont hurt the VE at all because it is not restricting it.

i don't beleive the hyped 10hp numbers for a pipe either though.. but i do know there are losses there, and they can be improved. the existing pipes clearly fall short of what the alternative offers. and for the most part, we are comparing the same diameter pipes, stock to aftermarket, but the aftermarket pipe doesn't have the reduction right after the turbo, the aftermarket eliminates the rubber (which expands), the aftermarket has less bends, and the aftermarket pipes generally are shorter (the upper moreso then the lower). bottom line, stock pipes are there, but aftermaket pipes are better

 

That is true, but only if the intake piping is extremely restrictive, and since over 500whp has been achieved with the factory IC pipes, I have a difficult time believing they are extremely restrictive.

 

ok, sooo. are intercooler pipes a waste of money (as far as performance) on an evo with decent mods, but stock turbo? has anyone actually dynoed before and after while just adding the pipes and nothing else, to see if they do anything???

 

AMS web page says the lower intercooler pipe restricts down to 1.5" in diameter. that is pretty tight. because of this, i bet you reach choking point before your pulling enough air (or pushing in this case) to get 500 hp through that small a pipe without using different fuels.

so who has made 500hp on the stock intercooler pipes? that means you have to have the stock turbo right? and the stock intercooler.... (serious question, cause i don't know if the stockers will bolt up to aftermarket turbos. never tried it) i'm sure it can be done if your using a more effiecent fuel that requires less air to burn (i.e. alcohol), but i bet they could make more power if they swapped them out

just think, if that lower pipe causes a 1psi drop in pressure across the restriction, then that is a noticable amount of power.

spending 400 dollars on an intercooler pipe is a bit obsurd. thats why i am going to make my own. but yes, changing them out will benefit you.

 

It shouldn't really a matter of if one has the stock turbo or not, but rather the displacement of the engine (which obviously doesn't change unless one installs a stroker kit).
What I noticed with IC pipes is the transient response felt quicker. I wouldn't consider new IC pipes to be a 'core' mod like cams, exhaust, and a good means of tuning, but they are worthwhile where improving street feel is concerned if nothing else.