Nick B

Like many, I must appologise for raising a question which has probably been done to death - but no search - doh...

Can someone explain in simple terms the pros / cons of Panel Filters v. Induction Kits.

I'm interested in:
1) affect on power
2) affect on noise (cabin noise is already loud enough )
3) risks to engine
4) affect on insurance

I have an MY00 with Scorpion mid section and back box.

Cheers all,
Nick

chiark

1) effect on power: Scoobysport claim the ITG panel does good things, I personally believe that an induction kit does more

2) Noise: panel = quiet. Kit = noisy (induction roar, plus much more sound from turbo and dump valve). I love the K&N noise

3) Risk to engine. Anything is a risk, according to Subaru. I know of no MAF failures with K&N, which is why I went for one. I do know of failures with Blitz and HKS... Panel should be safe too, but my Ramair panel leaked goo, which I was not happy with!

4) Tell 'em. Should make no difference, but as you're changing you're best off disclosing your modification.

If you want to know what's involved fitting a K&N kit, check my guide.

Nick.
(link pimping again)

Nick B

Thanks.

I've seen the MAF mentioned before. What is this, what purpose does it serve, and what happens if it fails?

(OK, someone has to ask the really dumb questions...).

Cheers.

john banks

I agree with Chiark except for number 1. My car on ITG feels just as fast as with K&N 57i overall - possibly a bit more at the top end from an induction kit but slightly less low down? Difficult to say because of the horrendous din which is why it came off. It makes a quiet decat setup seem civilised.

HELLOM8

You'll never get any serious power gains on the induction.
ITG panel filter is OK, better throttle response, shouldn’t cost on insurance, just don't squeeze it if you fit one, as you'll get oil contamination. The induction kits increase the induction noise quite a lot and in previous experiences they make the car slower.
Of course however many people responded to this thread, there won’t be two opinions the same.
I’d play it safe and ITG panel filter it, or just leave it alone.
Cheers.
Ian.

Scott W

I have had both the ITG and the K&N, and out of the two I prefer the K&N purely for the noise aspect more than anything!

However, myself and friend who have near enough identical cars ran at PE, and he was running with an ITG and of course myself with the K&N. The differences between the two were that lower down in the rev range he had more torque, but as the revs got higher, his tailed off slightly and mine stayed relatively flat (and slightly higher than his from around 4½k-5k onwards). Therefore I'd say they are almost identical, and it's down to personal preference.

HELLOM8

MAF, sits in-between the filter and the intake pipe, and it measures the air flow after it has passed through the filter, being that of the flow going into the engine.
When it fails you buy a new one. I think the measurement goes into the ECU and the fuel and air mixture is calculated for detonation (not really sure thought).

scoobysnacks

How can a more freely flowing Induction kit reduce the power anywhere in the rev range when it allows the engine more of what it wants (air)? Not saying it doesn't, but was wondering what the technical explanation is...

chiark

SS, I really wish you hadn't asked that. My brain's just crawled out of my ears...

john banks

I was sidestepping that one too Chiark!

A POSSIBILITY is that the airflow through the MAF is more laminar and less turbulent, resulting in a lower reading than would be the case with the original airbox setup, which is what the car is mapped for. As a result fuelling can be over-lean. It strikes me that the fuelling at 2000-3000 RPM is relatively lean on boost on a MY99/00 UK spec anyway, so going more lean may rob you of torque. The car is so rich at the top end the slight leaning probably helps a little bit. This is THEORY and opinion, not set in stone.

[Edited by john banks - 2/21/2002 5:08:21 PM]

FOZ STiV5

Have to say thats a fine answer John.....

In simple terms it is all about balance.... air is nothing without fuel and ignition. It must be optimum for optimum power. Therefore ....huge exhaust+free flow intake+small turbo free rev turbo = could equal massive gush of lean mixture .....then ecu playing catch up....

At least that the way I see it..... As john knows I have been playing with a number of configs.......

L8r

Julian

scoobysnacks

Ok, I understand the 'too much air low down in the rev range theory', however in later cars doesn't the ECU learn to compensate for this to an extent and add more fuel, or isn't it that clever?

FOZ STiV5

Well,

In my experience with my current STiV .... I could tell no difference with a Blitz SUS and a K&N panel. Other than noise!!


And how the ecu compensates is a key issue...... especially were boost is concerned..... >the boost regulator<... my experience is that this can be too slow for a very free flowing air supply in and out.

...I have replaced my Blitz with a panel... and that is the way it is staying.

Julian

john banks

If it fuels based on MAF and the MAF is under-reading compared with before then it will be leaner. So no compensation will occur.
(theory only)

[Edited by john banks - 2/21/2002 10:05:28 PM]

subster

I am getting unichip fitted and thinking of putting on an induction kit, the place has a rolling road if the induction kit was put on first could they map it for perfect air/ fuel mixture or is this impossible

john banks

Sounds sensible IF the theory is correct.

dowser

I also think it's related to airflow past the MAF - with a normal cone air is being sucked in very close to it, somehow confusing the sensor.

Has anyone gone from a normal under-bonnet cone, to one of the APS pipes which locate the cone in the inner wing? This would prove/disprove the theory (much longer run to the MAF should hopefully smooth out airflow) I think Bob Rawle runs one of these?

Richard

john banks

If the airflow is even smoother then the MAF could read lower for the same mass of air? I thought a few people had had flat spots and loss of torque with the APS wing, but this had been acknowledged by APS as a consequence of the filter being good for airlow for 500+ BHP engines?