GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: Rideandy on 07 January 2007, 16:08
-
Please can you tell me what advantages there is with having cold air sucked into the induction system and is it worth going down the route of venting?
I love the look of the vent but not sure if I should spend my money on other mods.
Cheers
-
i'd imagine the difference would be minimal.
it's more of a styling issue i think.
I've just run a 70mm feed to the vent below the fog light next to the horn.
-
your'e engine needs as much cold dence air as possible for more power and with a cone filter they suck air from the engine which is warm and lower's power...With a vent your'e pulling cold air from outside the car and you also get nice induction noise...you can also run a hose like monkeyalan (altho i recommend using plastic hose as this is unaffected by engine heat unlike metal flexi stuff)...regarding other mod's first induction, second exhaust and then a decent chip
-
Monkeyalan, has the 70 mm feed made a noticable difference?
Boneybradley, There the mods I had in mind,K+N induction kit being resent out tomorrow.
Cheers chaps.
-
you may not notice it that much but it is always better to have a feed of cold air rather than just hot air in the engine bay
-
Monkeyalan, has the 70 mm feed made a noticable difference?
i did it at the same time as a k&n panel filter. It did seem to to rev more freely and have a bit more oomph at the top of the rev range. not mindblowing but noticable.
-
I dont think having a vent in the wing will make any difference to a cars performance.
Yes it will perform better if it got only cold air, more dense/bigger bang!
But a cone filter draws air from all around it not just one side.
Perhaps this is why some say a standard air box is just as good.
:undecided:
-
Cheers Chaps
K&N sitting on kitchen table, will fit tomorrow! :smiley:
-
For future reference I plan on putting an induction kit in, do any come with cold air feeds or is it simple to just add your own ?
-
The K&N 57i induction kit comes with a cold air feed pipe, just a length of flexible hose.
Cant say about any of the others coz I wont buy anything else! And as I have had a K&N on my cars since 1981..........
-
Len , I got the pipe ,bought from K&N but seems tight with all other bits, need to have a good butch this weekend!
Cheers mate.
-
the thing about KnN style what i call 'open' induction kits is that they can easily suck hot air in straight from the engine bay, and therefore give very very little, maybe no performance increase.
if your serious about gettin a good induction kit, then u wanna look at spending a fair wedge, something like the pipercross viper, or BMC CDA is where its at, a fully enclosed filter with cold air intake, so the only air it gets in is through that air intake, which can be positioned to suck the cold air that would normally go straight through the bumper, without having to worry about the hot air in the engine bay.
granted the BMC is about 150 - 200 quid, but when i was involved with fiat mod testing we were seeing about a 10% performance increase with only a CDA and a supersprint mild steel back box :cool:
-
Cheers Mase.
All the induction kits I have seen people talk about seem to have a small piece of pretty crappy looking pipe with them. Granted you could add one yourself but it seems to defeat the object of buying something if your not given all you need or your not going to see the increase you would like.
However, Len seems to get on OK with K and N so I might just be talking crap.
Len, where about do you attach the pipe and run it to and from out of interest ?
-
ive actually got the KnN on mine, but only cause it came with the car.
u will see a slight increase, mainly due to the air being able to flow more freely through the throttle body, but dont expect any more than a couple of BHP.
and the pip that comes with it is crappy, only a couple of inches in diameter, mine is attached to the lower intake grill on the drivers side, then just cable tied so that it points at the filter.
i can try and take a couple of pics, but dont know how much use they would be.
-
So you can either:
A) fit K&N with their piece of pipe
B) fit K&N and fit some better pipe with a wider gauge ?
C) buy something more expensive :angry:
-
bingo.... got it in 1 mate.
if u want to free up a bit more torque, smooth out the power band and let the car breath more freely, then number 1 or number 2 will be fine.
but if your aiming for a large ammount of BHP increase, id reccomend gettin a decent enclosed filter which would maximise the ammount of cold dense air going into the engine. :nerd:
-
I agree the pipe supplied with the K&N kit is a bit naff and their fitting instructions totally inadequate! A couple of cable ties and a brief decription.
All you can really do is site one end below bumper level and the other close up to the filter. Not much to attach or secure it to and you have to wedge it around the alternator belt/fan.
I always recommend K&N because they were the first of the type and always look good. Can be cleaned, make a nice noise and give a recognisable increase in performance.
Also the first one I bought was for a Chrysler Alpine and they supplied a blank plate for me to cut to suit that particular carb and I chatted to the guy that made em!
To be honest I dont hold any great store by air temperature giving any better performance. I mean do you really feel that your car is faster in the winter than on a hot summer day????
Nah its bunkum! So why worry about it?
Oh and mase if you really want large bhp increases you need throttle bodies! And then where are the filters? Yes they are right out front taking air from right behind the radiator!!! You dont see cold air feeds on throttle body set ups!
Or again 2 dble choke carbs, no cold air feeds to them either!
But again I am thinking of putting a vent in my wing! Why? Because it looks as if I'm paying homage to that cold air theory - but honestly I dont believe in it!
So I'm a hypocrite! :laugh:
-
all that air temp stuff is about how dence the air is isnt it? with cold air bein dencer than hot air meaning the oxygen molecules are more tightly packed together resulting in a higher % of oxygen getting into the throttle body resulting in more bang? or something.... :tongue:
and Len, you do raise a good point about the throttle bodies, you gotta excuse my limited knowledge when it comes to that sort of thing, im still young lol, and up till now ive been working with spi engines rather than mpi.... but i always thought that the only reason cars with that set up used top mounted filters was due to space available....
i mean, if this cold air lark wasnt the case, why would companies like KnN even bother providing a cold air feed for their kits? :wink: :tongue:
-
Being a scientist :laugh: I can see how they can explain hot air versus cold air and it does make sense (as mase says).
However, I dont think there is a massive difference in the oxygen content of cold air and hot air but getting any air you can into the engine (where air is limited) will help as any engine isnt that efficient. Isnt a supercharger basically an big air inductor after all but its belt driven to force air into the engine ??
A cold air intake according to Wikipedia (I know this is getting very sad) :laugh: is:
"A cold air intake is a system used to bring down the temperature of the air going into a car for the purpose of increasing the power of the internal-combustion engine"
"The most basic cold air intake replaces the stock airbox with a short metal or plastic tube leading to a conical air filter, called a Short ram air intake. The power gained by this method can vary depending on how restrictive the factory airbox is. The placement of the filter is usually directly in the engine compartment. The overall benefits depend on the specific application. Power may be lost at certain engine speeds, only to be gained at others. Because of the increased airflow and reduced covering, intake noise is usually increased."
"Better designed intakes use heat shields to isolate the air filter from the rest of the engine compartment, providing cooler air from the front or side of the engine bay. Carbon fiber can be used for the piping instead of metal, lowering weight and insulating the air from the engine bay in some cases."
"The most extreme designs, sometimes referred to as Complete Cold Air (CCA) intakes, route air from outside the engine bay, usually from the wheel wells (although an extremely poor choice, as the air pressure is low), front grill (high air pressure), or a hood scoop (moderate air pressure). The intake can be placed such that the forward motion of the car pressurises the air coming in, creating a ram-air intake."
So best place for any ducting should probably be to force air into the duct under pressure from the speed of the car :wink:
-
OR just supercharge the beast :cool:, that would rule.
F**k knows what that would do to your insurance though :laugh: