yeah, thats what i ws thinking they would do mostly. cool great thread, i can feel the tension. haha

 

But getting 500hp does not necessarily involve an increase in the volume of air moving through the pipes.


The turbo was a GT35R, and the IC was stock. Hmmm, perhaps he did have a lower IC pipe solution. It's been awhile, so I can't recall all the little details.

 

your right... you don't need more volume, but you do need more density, and higher density means higher temps. if your going to have higher temps your going to want an intercooler to accomidate that. the stocker is pretty big, so it might not pose an issue.... but with a GT35R i bet they had a lower intercooler pipe because the outlet of the compressor housing is bigger then the stock turbo isn't it?

 

You may be right about the lower IC solution. I can't remember, but it seems like it would be a necessity.

Nevertheless, the larger turbo gives higher density but runs more efficiently, and therefore the charge is cooler. This is why a larger turbo gives more power at the same boost level.

 

I bought my lower I/C a week ago from AMS for $185 by mentioning EVOM. it feels just a bit quicker with that boost hitting a little harder. shifting feels ten times better though. catches quicker and no shaking. it also almost eliminates that push you get when you let go of the gas to shift and you can hardly feel 1st catch. my mom wouldn't ride in my car b/c it hurt her back (step-dad driving when I was out of town for business), but I took her out the other night and with her blonde hair and no knowledge of cars could notice how much smoother it sounded, shifted, and accelerated. i always drive real slow with others in the car so they don't get that rocking from take off and shifting, but now I don't have to worry about it. it made it worth it to me.

 

I agree with some of you about the pressure differences and the VE of the engine. I also agree that the I/C pipes alone won't warrant a lot of whp, but it's the combination of aftermarket parts that make the efficiency of the engine rise and the whp gets more and more significant the more you free up restrictions.

Having said that, let's imagine the muffler/cat-back being the upper I/C pipe and the downpipe being the lower I/C pipe. You can imagine that you'd get more increase in whp (same principle of pressure and volume) from freeing up the catback and muffler than you would with keeping the stock catback and just changing the downpipe. I would rather go from small to large than to go from large to small. Going from large to small would certainly increase the velocity of air going into the intake manifold and therefore heat because of increased pressure. Going from small to large would decrease pressure and the charge would be cooler and would warrant more whp (especially since Buschur's solution also eliminates the rubber hoses and the bends and the length).

I'm an engineer (software) and so, we can talk physics if you like...

-M

 

It is true. think of the straw analogy that KevinD pointed out..

I have not replaced my IC pipes yet, but I did on my 2nd gen DSM. I didn't pick up much more HP, but the throttle and boost repsonse was definately better (think big micky D milkshake staws here) That was on the stock T-25 (T-toosmall)

just my $0.02

 

very true about the turbo, but in order to run 500hp you will need like 30-40 psi of boost which means much higher charge temps.


also a bigger turbo is not always more efficient... it really just depends on the efficiency map of that given turbo and the area you are running the car at (but in general, yes your right)

 

agreed with the first paragraph. as for the second paragraph, your just thinking of the pipe change difference as a throttle. really you would need to look at the energies in the air going into the engine. sure the cooler air sounds nice, but a higher velocity is nice too (less work for the engine to suck). i would imagine that your energies will be the same either way, and therefor it wouldn't make a difference if you have the restriction early or late. something to look into though....

 

Actually you can't measure "energies" in the way you are describing it because there are too many variables to look at. I see what you are trying to say and yes, higher pressure would be nice also, but in the case of a larger intercooler, the pressure drop is more than made up for by the increase in density of the air. We are really concerned with how much air we can get into one compression stroke (mixed with fuel of course). Cooler temps will make more air per unit of area. If fuel is then returned to match this increase, then you get your beloved horsepower.

While it may be less work for the engine to suck, getting "blown" hotter air is less efficient in my book..

-M

 

well if we want to get technical, lets begin.

the efficiency of an pump is:
Ve = Q/(D*N) where Q is the delivery rate, D is the displacement and N is the pump speed. because Q is volume per time, it doesn't matter if it is hot and going fast or cold and going slow. the cold air will be more dense, but not moving as fast, but the Q will remain the same, thus the Ve doesn't make a difference if we put an orifice (or restriction) early or late in the path.

 

The simple equation above represents how Ve is determined, by dividing the actual pumped volume by the theoretical pumped volume. It doesn't examine factors that affect Q in this application, which are obviously far more complicated!

Anyway, carry on...

 

can u make ic pipe with holders like stock one? ..can u make upper ic pipe for me and one for u? and i would rather have 3 piece like stock one....i hate 2 piece style... long solid pipe hard to install and hard to take it out.....plase pm me about this....thanks

 

Suck it up man You can do it. You think this install is tough, just wait until you install cams or a turbo... An god forbid you have to pull the tranny to instal a clutch. You can always get someone in your area w/ an Evo to help out...

 

IT WAS TOUGH...it took me halfday ...casue i m perfectionist,... for me stock works best.. anyone want my upper ic pipe?its logic..i will let it go very cheap,.pm me...