Upgrading the size of your Intercooler?
23 July 2006, 12:06 PM
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Upgrading the size of your Intercooler?
Now there's a few sites saying their intercoolers are upto 50% bigger...
But is that really an advantage? wont that just increase the lag?
Cheers for your views!
Plums..
But is that really an advantage? wont that just increase the lag?
Cheers for your views!
Plums..
23 July 2006, 12:47 PM
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Shouldnt increase lag at all.
Air passed though the intercooler so the larger the inter cooler and the more air that cools it the better the performance.
If you go for a front mount then you will add some lag due to the turbo being at the back of the engine and the mount being at the front.
Tony
Air passed though the intercooler so the larger the inter cooler and the more air that cools it the better the performance.
If you go for a front mount then you will add some lag due to the turbo being at the back of the engine and the mount being at the front.
Tony
23 July 2006, 12:55 PM
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Ok cool I was just worried that by increasing air volume you may increase the lag....
Anybody know of any good top mount intercoolers at a good price?
I've seen a few on t'ebay which are very cheap but not sure about quality?
cheers,
Plums...
Anybody know of any good top mount intercoolers at a good price?
I've seen a few on t'ebay which are very cheap but not sure about quality?
cheers,
Plums...
23 July 2006, 10:19 PM
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Whilst what Tony says is fairly true, it's only half the story
Ultimately by increasing air volume, simple laws of physics that the turbo has to flow more air to pressurise the larger volume system, so bigger = more lag. However, most after market top mount intercoolers have lower resistance to flow (and lower pressure drop across the intercooler) than the OEM WRX unit. Lag is broadly a function of volume and resistance to flow,, so you gain on one hand and lose on the other - net effect is probably not a noticable difference.
As lag is determined broadly by volume of the system and resistance to flow, positioning of the turbo and intercooler isn't actually drectly relevant. However, longer piping to FMICs does tend to result in larger volume and higher/no better resistance to flow than a good aftermarket TMIC, hence most FMIC give more lag.
There are two things that make a good intercooler. One as Tony says is how much it cools the air. The other is how little pressure is dropped across the intercooler. On a tuned WRX running a TD04 at say 18psi boost, the standard intercooler is wasting 1-2psi of that boost pressure through flow resistances. Some of the better intercoolers only lose a 10th of that figure. hence the turbo can either work at higher efficiency or produce say 1psi more boost for no more effort = more power.
The bug/blobeye STi intercooler is actually a pretty decent unit and a signficant step up on the WRX one, and can be had for decent money second hand. After that, a decent bar and plate type unit from APS, MRT, Hyperflow (and several others) may do a better job but will tend to be a lot more money.
Ultimately by increasing air volume, simple laws of physics that the turbo has to flow more air to pressurise the larger volume system, so bigger = more lag. However, most after market top mount intercoolers have lower resistance to flow (and lower pressure drop across the intercooler) than the OEM WRX unit. Lag is broadly a function of volume and resistance to flow,, so you gain on one hand and lose on the other - net effect is probably not a noticable difference.
As lag is determined broadly by volume of the system and resistance to flow, positioning of the turbo and intercooler isn't actually drectly relevant. However, longer piping to FMICs does tend to result in larger volume and higher/no better resistance to flow than a good aftermarket TMIC, hence most FMIC give more lag.
There are two things that make a good intercooler. One as Tony says is how much it cools the air. The other is how little pressure is dropped across the intercooler. On a tuned WRX running a TD04 at say 18psi boost, the standard intercooler is wasting 1-2psi of that boost pressure through flow resistances. Some of the better intercoolers only lose a 10th of that figure. hence the turbo can either work at higher efficiency or produce say 1psi more boost for no more effort = more power.
The bug/blobeye STi intercooler is actually a pretty decent unit and a signficant step up on the WRX one, and can be had for decent money second hand. After that, a decent bar and plate type unit from APS, MRT, Hyperflow (and several others) may do a better job but will tend to be a lot more money.
24 July 2006, 05:27 PM
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ive recently fitted a my04 wrx intercooler onto my my00 classic,as far as im aware the 99/00 intercoolers are the same...... the 2004 version is larger,and i had to purchase the later drivers side bracket in order for it to fit.... it does cool very well....... but apparently it does not flow as well as the later classic version,when mapped on my apexi pfc the mapper ( jollly green monster ) couldnt run as much ignition advance as a similar car but with the my00 intercooler fitted,there are variations of course as no two cars would be the same,even with the same specs due to internal differences with machining/wear etc,but he had noticed a trend that the later intercoolers did not flow as well.....
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