Don't like the adverts? Click here to remove them
intercooler
- Thread starter 24carrot
- Start date
Beau
Well-Known Member
- Joined
- Jan 28, 2011
- Messages
- 2,014
- Country Flag
If you make the system tight and sealed 100% you will get good results. A front mount Intercooler will require more pipe work than say a top mount. It will increase Lag by a touch, how much I'm not too sure... However you can cure the lag simply by winding the boost up a little, getting a better exhaust/down pipe system and tuning the fuel pump.
Blown80
Well-Known Member
Either engine will benefit from adding an intercooler to the charged intake system. The cooler the air on entry to the combustion chamber, the denser the air therefore the more oxygenated the air is. That is a known factual outcome of colder air where other factors remain the same such as ambient pressure.
As for front mount versus top mount, there are opinions on this but both outcomes are similar.
A top mount doesn't have quite the same amount of cooling efficiency due to a limitation on airflow input and through put effectiveness. Top mounts also have the issue of heat soak from the engine and engine bay, although an under core fan can assist with this. The pipe length is shorter which is only a very slight benefit in reality.
A front mount intercooler has much better cooling efficiency with cold air entering directly in and through the core. They can often be larger as well. So the air is generally denser and therefore more oxygenated again, more so than top mount. There is longer piping, but I have studied the mathematics of air volume versus flow, and essentially the rate of consumption of the air by the engine and the rate of flow means the added length of tube has an approximate 0.3 of a second difference between that of a top mount air flow rate when measuring from turbo exit to cylinder entry. Most people cannot detect this difference. The denser air of the front mount compensates for this slight difference.
So ultimately either intercooler mounting system is reasonably comparable in performance.
Greater reduction in turbo lag can be achieved with a performance exhaust than between front or top mount intercooler choice. Either intercooler will work fine, but a better exhaust and dump pipe design will improve lag.
As was noted though, you should always consider your fuel tune in relation to adding intercoolers or boost. Adding more air through increased boost or more oxygenated air (cooler, denser) via an intercooler, will essentially lean out your AFRs. Tuning a mechanical fuel pump or chipping a modern electronic fuel injection system will get the most out of adding an intercooler, not the intercooler alone.
It should be considered as part of the package.
Just as importantly as mentioned in another thread, adding merely fuel will increase power but at the same time increase heat. Keeping the balance right via ideal AFRs will increase performance safely. An EGT gauge will soon tell you if you have the AFRs right or not if you don't have access to a dyno.
Cheers
As for front mount versus top mount, there are opinions on this but both outcomes are similar.
A top mount doesn't have quite the same amount of cooling efficiency due to a limitation on airflow input and through put effectiveness. Top mounts also have the issue of heat soak from the engine and engine bay, although an under core fan can assist with this. The pipe length is shorter which is only a very slight benefit in reality.
A front mount intercooler has much better cooling efficiency with cold air entering directly in and through the core. They can often be larger as well. So the air is generally denser and therefore more oxygenated again, more so than top mount. There is longer piping, but I have studied the mathematics of air volume versus flow, and essentially the rate of consumption of the air by the engine and the rate of flow means the added length of tube has an approximate 0.3 of a second difference between that of a top mount air flow rate when measuring from turbo exit to cylinder entry. Most people cannot detect this difference. The denser air of the front mount compensates for this slight difference.
So ultimately either intercooler mounting system is reasonably comparable in performance.
Greater reduction in turbo lag can be achieved with a performance exhaust than between front or top mount intercooler choice. Either intercooler will work fine, but a better exhaust and dump pipe design will improve lag.
As was noted though, you should always consider your fuel tune in relation to adding intercoolers or boost. Adding more air through increased boost or more oxygenated air (cooler, denser) via an intercooler, will essentially lean out your AFRs. Tuning a mechanical fuel pump or chipping a modern electronic fuel injection system will get the most out of adding an intercooler, not the intercooler alone.
It should be considered as part of the package.
Just as importantly as mentioned in another thread, adding merely fuel will increase power but at the same time increase heat. Keeping the balance right via ideal AFRs will increase performance safely. An EGT gauge will soon tell you if you have the AFRs right or not if you don't have access to a dyno.
Cheers
Don't like the adverts? Click here to remove them
- Joined
- Mar 1, 2010
- Messages
- 5,522
Well written Chris. I think people often think throttle lag is caused by turbo lag where it is in fact low down lean mixture.
My idiot question for today - what does AFR stand for??
Charlie
Well-Known Member
- Joined
- Apr 9, 2010
- Messages
- 899
- Country Flag
AFR or Air Fuel Ratio
Ahh ok - thanks!!
Scott
Well-Known Member
- Joined
- Mar 17, 2010
- Messages
- 1,046
I wonder if this was what the orginal comment was all about? IIRC people comment that the 24v doesn't seem as quick off the mark as the 12v (when both are in standard form), and when people have investigated they have found that the 24v seem to have been set a bit lean on fuel when low down in the rev range, possibly as an economy measure. So some people have felt they are a little sluggish when compared back to back.
Jon did some experimenting with his 24v and found a few tweaks which got the 24v to perform as expected. I wonder if the orginal comment was referring to an intercooler was need on 24v to rectify the slow pic up, which in reality it wouldn't unless the fuelling was adjusted as per Chris' explanation.
