Yes I've been told that as well, but mine didn't half go better flat out with a new lambda. TPS made a huge difference too.

Bit confused as to what the differences are on the two maps....?

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Nothing to see here

Ah right sorry, wasn't looking at it properly.
Big difference shown there, but it is pretty down on power to start with - was the standard air filter made of concrete of something?

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Nothing to see here

The only thing changed was the induction setup. I was hoping for a standard run to show 165 ish hp, maybe a bit higher with the small mods from my first post.

The lower figure was mainly due to the overfuelling I guess. A new Lambda and retest are the next plan.

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Very similar setup, the flexible ducting is a bit more turbulent than the silicone hose. I like the front scoop.

It looks like the engine temp sensor needs replacing on mine so that is the next job, and then some warmer weather hopefully for the next RR : )

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Spanner Monkeys Monkey Spanner
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yep, attacked my 200 sx intercooler with a fire extinguiser many a time

Here's the printout form the RR at the end of March



Temp sensor has been fixed, I'll put the original air box and a new paper filter on it for the RR on the 18th April, see if I can get an accurate before graph at last.

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Spanner Monkeys Monkey Spanner
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Ran a similar sort of idea but with a K&N Apollo :-) although it's a c.i.s . Don't really fancy my filter that exposed and so close to the floor, as per one of the pictures above. Looks like a lot of effort gone into it though

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Does this really have any relation to top end or torque? On a stock intake manifold any of the pulse tuning is done within the manifold and plenum.

Its also not right in that long is for torque and short is for top end if thats the way you are thinking! There are overlap boundaries with pulse tuning so an 4ft length could yield more top end than an 8 inch length.

Fluid dynamics is a bit of a nightmare, I wont pretend to understand it, but when I complain about it the induction guy just says "Take it up with the guy who invented physics!"

On the C2 car, the VTR/S has aircon and only room for a small pipe behind the bulkhead. The GT doesn't have aircon and has room for a much longer pipe setup, which gives a bigger torque improvement.



but I take your point that there are no hard and fast rules. Denis made up his own induction kit and got some good figures at the recent RR in Purfleet.

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AS said above ram air in theory will do very little, even at 160mph the additional pressure at the intake is only going to be in the region of 0.03bar or less than 0.5psi. The advantage it may provide, which is a bit more difficult to quantify, is some reduction in the engine pumping losses. Although again this is likely to be almost insignificant.

The basic aim of any performance induction system is to provide the highest possible pressure at the valve around BDC of the intake stroke. An intake system which promotes good flow will allow for greater mass flow rate and therefore higher pressure. Additionally the greater the pressure gradient between the entrance to the intake system and the cylinder the greater the mass flow rate will be. As mass flow rate is a funtion of the air density as well as the velocity (assuming fixed intake geometry) it can be increased by increasing the density, hence cooling the air also improves performance.

The problem is, without drastic changes to the intake configuration (tb's or forced induction) none of the above can be varied enough to significantly increase the volumetric efficiency and therefore torque the engine produces.

The flow is caused by the depression caused by the cylinder moving down the bore - creating a region of low presssure. Air flows from the intake entrance because the pressure there is higher (atmospheric). Assuming a constant air density the greater this pressure differential the faster the air will flow and, taking into account the inertia of the air, the more will end up in the cylinder prior to the valve closing. The pressure difference is what creates the force on the air. It's all about loosing as little pressure through the manifold as possible.

The problem with intake systems is they cause pressure loss, where there a corners or large expansions of contractions turbulence occurs and eddys form.

Using a less restrictive system (large filter/larger diameter ducting) would result in slower airflow - the same mass of air still needs to travel to the low pressure region to balance to the pressure, but it has a bigger path to travel through. - Imagine 10 people trying to get through a 1 person wide corridor, to get them all through in'x' amount of time they would have to run very fast, if you were to make the corridor 10 people wide, they wouldn't have to run to all get through in the same amount of time..... If that makes any sense at all . The advantage of a larger system is less pressure loss as the air is flowing at a slower speed therefore wall friction etc will be less significant. Although there is a whole other area of resonance tuning and inertia tuning when talking about length/diameter of intake runners.

Throttle bodies work so well as so little pressure is lost between the intake valve and their entrance that the pressure at the intake valve is more or less atmospheric - the best it can be before using forced induction.

Fuel is always more or less an after thought. When you know how much air you can get into the cylinder you just put in the right amount of fuel to acheive the AFR you want.

I'd suspect the running of the trucks or more likely to be down to mapping although I'm surprised it makes much difference at all assuming they are turbo'd engines?

Don't quote me on that it's a guess but from my experience the difference noticed by taking out the air filter wouldn't be that noticable. Unless of course they have some specially designed induction system

There must be some explaination and you may well be right although it would be suprising that removing a flow restriction would reduce torque. Maybe the filter is used as some kind of flow conditioner, improving flow through the rest of the system.....