Forced induction

CraigMK4 · Post by **CraigMK4** » Fri May 23, 2008 4:20 pm

Hey guys, i currently have a K&N induction kit on my 1.3, the plan was to get a heat shield built to save it sucking too much hot air. Recently i've been considering getting a forced induction kit instead, does anybody here use one? And can you suggest a decent brand to go for too?

Cheers!

Redline · Post by **Redline** » Fri May 23, 2008 4:50 pm

Forced induction usually means either turbo or supercharging.

So do you actually mean something like a BMC induction kit, with an enclosed filter and proper cold air feed?

CraigMK4 · Post by **CraigMK4** » Fri May 23, 2008 6:27 pm

Yeh basically, something like this:

http://www.green-filter.co.uk/index.php ... 613a8122c2

polo-sib · Post by **polo-sib** » Fri May 23, 2008 7:55 pm

Easiest way for the forced induction I found was to shove the standard air box back on, replace the VW oval filter with the oval K&N filter which is Â£30. Then get a cold feed tube and feed it into the air box, thats how I did mine

Off eBay I got a 70mm ducting with polished trumpet end for Â£20, however the inlet for the standard box is 50mm, however a 60mm piping will go over it with a jubilee, so all you will also need is a straight silicone reducer from 70mm to 60mm with a jubilee clip to fix the cold ducting on.

As for the standard cone K&N kit i found it terrible I got really bad lag, idling and reving it was excellent under running performance it was terrible, plus the 60mm hose you got in the kit made from cardboard wasn't great quality. So I sold it the kit and did what I'm suggesting above, hope this helps.

Hardcore · Post by **Hardcore** » Fri May 23, 2008 9:48 pm

i was going to do this with the BMC. where you have a hole at the bottom of the bumper with a pipe straight into the air filter. i think thi s can cause problems thow as you get too much air and the car cant mix the petrol fast enuff. and i also think you might need a re-map. i suppose it would be a good idea if you had bike carbs, and a GT camshaft. and then a remap. would giv a vast improvement, but thats a lot of muney and hastle. i think if you just did the ram-air into your air filter withought any other mods, it could cause problems. well it did on my mates clio anyway...

polo-sib · Post by **polo-sib** » Fri May 23, 2008 10:30 pm

Hardcore wrote:i was going to do this with the BMC. where you have a hole at the bottom of the bumper with a pipe straight into the air filter. i think thi s can cause problems thow as you get too much air and the car cant mix the petrol fast enuff. and i also think you might need a re-map. i suppose it would be a good idea if you had bike carbs, and a GT camshaft. and then a remap. would giv a vast improvement, but thats a lot of muney and hastle. i think if you just did the ram-air into your air filter withought any other mods, it could cause problems. well it did on my mates clio anyway...

You can never have to much air, only so much air can enter into the engine, what cold air feed does, is it allows more concentrated air (oxygen) into the cylinders, but forced air would allow even more in as the pressure would be higher at which air enters resulting in even higher concentration of air. Secondly bigger pipes reduced to smaller pipes via reducers cause a natural Ram effect (or forced induction) this allows more air to enter due to a higher pressure results in a higher concentration of air.

But heres the catch with ducts, they suck donkey balls at lower speeds as theres no ram effect until you start gaining some speed, then you will see the effects at lets say 40mph where there air is now being rammed into the engine finally (this is where turbo and superchargers don't have this problem at lower speeds, whilst ducting does).

As for any additions to engine mods, you won't need any as your running an injection system, it will notice higher amounts of oxygen where it will automatically reconfigure the amount of petrol to it in ratio. But power gains will not be alot maybe 5bhp at 40mph and up.

As for your friends clio problem it might be due to piping causing restrictions, I built a custom pipe feed using 50mm pipes and elbows from B&Q in the past, it seems like a great idea until put into practice, it for some reason caused huge restrictions in air flow. Seemed great idling but then i put it into practice and it was hell pulling away something like 30seconds to get from 0 to 30mph

Should off seen me going up a hill in first at 5mph with my foot down, hilarious looking back now

Hardcore · Post by **Hardcore** » Sat May 24, 2008 11:01 am

ahhh ok. nice one. i cant see it losing loads of torque at the first 40 cus its still sucking the same. just not from in the enginee but from the pipe. i can understand it bieng a little bit. but not loads.

thanks for the info. i learned sumit today

dragon_green · Post by **dragon_green** » Sat May 24, 2008 2:35 pm

Guys, that is NOT forced induction.