Really, you don't believe in IC's? Think of it this way. You put a EVO cone filter on there. Why? It flows more air with less restriction (pressure drop). If you put the stock on back in with a used OEM filter. What would happen? You would loose performance & make the rest of the car work harder. Same for DP's & Exhaust, it helps the car as a system, and you would loose just as much performance with stock DP's. The lower the pressure drops the happier a FI car is.

Same kind of thing for the IC's. You are flowing more CFM & pressure threw the IC's. This causes back pressure, & the turbo has to work harder to get the added air threw the IC's This also heats them up more, & creates more heat (IAT's go up). The pressure on the inlets is higher then the outlets (turbo is working harder). So 15psi @ the turbo is no longer 15psi after the IC. This added stress is heat & flow, so the turbo will spool slower, & has to work harder, this in turn over heats the IC's & you loose performance. Once they are heat soaked, you loose a lot of performance & make the turbo work even harder for the same CFM & PSI.

Forget about ambient air temps. The only relevance is recovery time on the IC's. The charge air will ALWAYS be higher then ambient. The more you drive the car, & harder you drive the car, the higher the temp. The higher the IAT, the LOWER the HP & torque. This all puts more thermal stress on the engine. A turbo car will have intake temps higher then ambient. Most NA cars intake temps are around ambient. The lower the IAT is the more HP & torque you get. Every few degrees help. No car can have lower then ambient, but as ambient raises, so does IAT's, and if you have poor IC's, then the temp goes way up, that's why you loose so much performance in the summer.

IC's performance with a STGIII has been proven over & over.

 

Thank you for the explanation 2K S4 - What you say makes some sense but in part I remain unconvinced and a bit skeptical. I've seen dyno comparisons and such at other forums where it seems very difficult to tell any difference between stock and upgraded ICs. The reason I think that ambient air temp makes a difference is that the ICs have to do a heat exchange with the ambient air. I think once it gets high enough there is just not much benefit with a larger IC as all the air is just hotter. I don't discount that there is some benefit - but how much really is what I am wondering and I don't know - but I suspect its not great. It may buy you some time before heat soak sets in - but how much is the question and can the ICs actually prevent it and under what circumstances? I'm still not sure I understand why the upgraded ICs provide more flow then the stock. Isn't this determined by the size of the piping going in and out (and is there that much diff between stock and the various upgraded units?) and not the volume of the units per se (unless they indeed are too small for the flow). I still remain unconvinced that upgraded ICs provide more then transitory gains. (OK I'm just dense I admit...)

 

what size FMIC pipingdoes APT kit use ?

 

Flow, does an aftermarket exhaust flow more then stock? It's kind of the same thing. There are more rows, & it's bigger. This allows the higher CFM of K04's to flow more. If the IC can hold more air, & have more paths for the air to travel, there will be less air pressure lost from the turbo to push the air threw the bigger IC. We all know that a bigger exhaust flows more, same concept.

Heat. Take 1lb of metal & put it on the stove. Now take 2lbs of metal on the same stove @ the same heat level. What one heats up faster? What one cools off faster? The bigger one. More surface area = more cooling capacity. Bigger IC core = longer times to heat soak. @ the same boost levels & same intake temp, the bigger IC will be cooler on the other side, have higher pressure & recover faster.

Some cars don't show much gains (like my EVO 8) due to the stock IC being much more efficient. Look at ANY of the Subaru guys who swap from a Top mount, to a front mount, they show big gains. Our stock IC's are OK for K03's, but with K04's they can't keep up. Not only are flowing higher PSI, but much greater CFM. So at 10psi the k04's volume is MUCH greater then K03's @ 10psi.

Lastly, you can go TO BIG of a IC & that can hurt performance, it needs to be balanced to your CFM & boost. If your core is to big, there will be a big pressure differentational between the front & back. This is from the front being much cooler then the rear, this has to due with air flow over core & the core being to big for the turbo. There are some other factors, like air flow threw the core is a big deal, how much air is being aimed at the core & the type of core.

In summary, Stock IC's ok, for K03's, really BIG IC's not good, K04's need more IC's. ASP FMIC is great, & much more engineered over the others out there.

 

I cant believe you went and posted this after me trying to steal all my glory for the find[:@]

 

You also want to consider the practicality of this kit. With the ASP kit, you still have room to keep your rebar, but with the huge core on the APT kit you have to ditch the rebar. as a track car thats not too bad, but for a DD with out a rebar, crashes can become much more serious.

 

That is a pretty neat kit. The fan seems like it would definately help in low speed traffic type driving with your foot in and out of it. The intercoolers are a big deal. I wanted to add a few numbers in to the info you guys are sharin. they aren't perfect but it gives you an idea. when you pressurize air to say 15 psi you will gain 20- ? degrees in temperature and maybe more depending on turbo temperature (aand where your piping is running. the more psi the more temperature even up to or exceeding 500 degrees. this is caused buy squishing those little molecules togethor and making them rub against one another. I have read about tests where by adding an intercooler people were seeing that temp drop 40 or more degrees. they say every 10 degrees in temp drop the air density increases 1-2% which is also about the power gain in %. if it is 100 degrees out and your intake air temp is 100 degrees then the pressurized air entering the engine will be probably 150 or more. cool that back down to around 100 degrees with intercoolers then that is a pretty signifacant gain. the more restrictions and times you make those molecules collide with eachother the hotter they get. like 2k s4 was saying you do have to size them right cause if you had one to big you would spend some time getting that air to fill up the intercooler before it would pass out into engine (lag). I built an sti with stock intercooler and stock injectors but we added methanol injection to it. the meth absorbed alot of heat and the stock intercooler made for very little lag with increased boost pressure. we had a larger 20g model turbo. with a professional tune it laid down 400 wheel horse and 410 pound feet of torque and very low rpm all the way to redline. the only thing was that you always had to watch your meth tank and at 10 bucks a gallon for that and a very fun motor it made for and expensive car to drive. so meth or water injection is sort of an alternative to intercooler upgrade but those little guys are still very restrictive. I have one apart and it makes me wonder how the air even gets through it.

 

2ks4 - again thank you. While much of what you say makes sense - I can see a larger IC taking a bit longer to heat up and being a bit faster to cool down - but I wonder just how much time one is buying here (and I still say these differences may be much less under conditions of high ambient temp). And while I see how larger exhaust allow more free flow and better performance I don't see it for ICs - if that were the case a straight pipe would be better and the more baffles you add the worse it would be....anyway - obviously B5S4 owners are not the only turbo cars where larger IC upgrades are done - so obviously there is some advantage - and it makes some sense that more surface area will allow for greater rate of cooling. Still - (and again here is why I think ambient air temp makes a difference) - if the outside air is pretty hot to begin with (even if not internal engine hot - it makes a difference because we all lose performance from the less dense air) - I wonder just how much extra cooling one gets from just a bit more surface area/exposure...I'm just being devils advocate here....and the reason is that I hate the drop in performance I get during the summer when i try to push it hard...but I hesitate to drop another $3K (at least) into the car when it may not ultimately buy me much (except right at the margins - slightly delaying onset of heat soak - and maybe (maybe) recovering somewhat (but how much?) faster...I'm thinking it may be easier/more economical to just do some sort of water spray system and keep the stockers....(Though i do like the look/package of the ASP - very much - the extras seem like they might be worth something - oil cooler - beyond/improved from what we already have I assume...and not sure how much power steering cooling we need - never noticed it as a problem....still a slick package no doubt...but worth it in terms of real performance gains?

 

I had some wrong numbers in there when i wrote that. my apologies. If it is around 80Degrees outside then without intercooling at 15 psi you would see intake air temps of around 250 degrees. that is 170 degree increase. with intercooling you could cut that down probably 70% or more depending on how efficient they are. that is a 130 or so degree drop from intercooling. if it is 100 degrees out your intake air temps are going to be well over 250 degrees. that is hot air. I do agree that the outside air temp makes a big difference but without efficent intercoolers it your intake temp is over twice that of a naturally asperated car. once again i apologize for the numbers. there are some complicated formulas for this. alot of it also has to do with turbo efficency also which as we all know the little snails factory on these cars suck. I didn't mean to but into anyones info, just throwing my 2 cents out there.

 

Read this http://forums.evolutionm.net/showthread.php?t=260479
I think you are missing that the intake charge is WAY above ambient. Bringing it down to ambient would be AWESOME. lets just say it's 80deg out, your intake charge could be 160deg with just one good run. Yes, a straight pipe would flow a lot better, but it would do nothing to cool the air. The IC is just a big heat sync, or heat exchanger. Like the radiator, you would not run with out one of them or put a really tiny one on there?

In the warm weather it will make the biggest differences! YOU WILL gain WHP just from changing the core, YOU WILL be able to keep your WHP longer when it's warm out or your pushing it. YOU WILL gain some throttle response & lower spool time.

If you don't track the car at all, or drive really hard, then a PS & oil cooler are not as important, well the oil cooler still is. The PS fluid gets really, really hot, there is a ghetto stock one infront of the radiator. Yes, water injection will basically do the same thing, but to much less of a degree, it will not help the flow rate of the IC, just drop the temp down. There great, but you got to keep the tank full! It's all moving parts, so not as reliable as just putting in a bigger IC.

There is no need to drop $2k on bigger IC's, you can get the RS4 ones for around $1000

I think you need to head out to a local dyno day with boosted cars. Look at the Stock IC cars dyno, then the upgraded IC cars. All the proof you need will be there.