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The mkiv Supra Owners Club

Changed from induction back to stock filter - question


AJI

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I've been using an 'induction' setup over the past couple of years but last night I changed back to the old stock air-box and filter setup.

 

With the boost controller settings I have, the 'induction' setup would see 1.2bar pressure on open throttle, but now after going back to the stock air-box and filter I'm only seeing 1.1bar of pressure with a slightly longer time to reach that level. Making the car feel a little lazy to what I'm used to.

 

I have seen many mention on here that the stock air-box set up is the better performance option over a cheapo induction setup, but this doesn't seem to be the case in my situation.

 

 

Would there be any reason as to why a direct change over like this would see a 0.1bar boost level drop?

 

 

[Just to tick a few boxes; I have made sure all pipe work is fully on and tightly secured and also that the stock air-filter is clean. No changes were made to the boost controller settings between the different setups].

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It may be a sign that the stock panel filter is actually taking the time to extract particles from the air rather than letting everything pass through unrestricted as is usually the case with cheap induction kits.

 

An aftermarket panel filter that breathes easiers from TRD or K&N may resolve the issue.

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Won't the ECU need to 'learn' the stock air box again to adjust ?

 

Could be I suppose. I only gave it some 'beans' on the way home from work tonight to check the difference. So since replacing back to stock air-box its only done about 20miles.

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Im going with Pedro, probably the filter actually filtering stuff, and getting a high flow panel filter should help. But you'll find more benefits when youre actually moving at speed due to the ram effect of the intake scoop :)

 

The bonnet scoop has nothing to do with the air intake it is there to direct air on to the manifold.

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If its warm outside you will most likely get a small reduction in power, mine has definately less power on hot days, which is about 12 days a year haha.

 

I've kinda ruled out the weather temps as today and yesterday have been more or less the same temps where I live.

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Im going with Pedro, probably the filter actually filtering stuff, and getting a high flow panel filter should help. But you'll find more benefits when youre actually moving at speed due to the ram effect of the intake scoop :)

 

Pair of old tights? ;) j/k

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Going from an Apexi filter to stock airbox made no difference on my old bpu car (also dynod it before and after, no difference).

 

Do you have the two cold air feeds fitted? I have seen on some air boxes the bottom feed collapsed in the centre which would certainly not help matters, was it all square?

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Two cold air feeds properly aligned, secured to air box and I checked them through for any blockage before re-fitting.

 

 

 

Maybe the self-made bit of hard plastic that I cut out to stop the hot engine air freely flowing in to the induction filter worked better than I thought?

(Probably should have mentioned this earlier. But on the induction set up I screwed in place a piece of plastic to create a barrier between engine and induction filter. It was never a seal of any type as it allowed air to flow over the top of it, but it maybe did a good enough job to stop a large amount of hot air reaching the filter? - creating a situation whereby cheapo inductuion kit vs stock airbox created a performance balance towards the induction setup).

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I'm out of ideas then :)I also had a home-made sheild on mine which sealed it off from the rest of the engine so I don't think it's that. What induction kit did you have on before? Maybe as suggested above it was simply not filtering as well as the stock filter...

 

I also did one dyno test without any filter (this was between removing the induction and fitting the stock one), the car gained 10bhp, so the filtering certainly does reduce power very slightly. It built torque a bit quicker too. Here are the figures:

 

Apexi (sheilded): 428bhp

No filter: 438bhp

Stock induction: 428bhp

 

All done on the same day @ SRR

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I'm out of ideas then :)I also had a home-made sheild on mine which sealed it off from the rest of the engine so I don't think it's that. What induction kit did you have on before? Maybe as suggested above it was simply not filtering as well as the stock filter...

 

I also did one dyno test without any filter (this was between removing the induction and fitting the stock one), the car gained 10bhp, so the filtering certainly does reduce power very slightly. It built torque a bit quicker too. Here are the figures:

 

Apexi (sheilded): 428bhp

No filter: 438bhp

Stock induction: 428bhp

 

All done on the same day @ SRR

 

Hi Homer.

 

Do you have some pics of the shield setup?

 

I need to make one for my car...

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Well, I put the induction kit back on and re-jigged the shield that I made. Seems to be running strong again with boost and power levels back to previously.

 

I played around with the stock air box and boost settings and it easily made the 1.2bar boost with a higher gain setting. Just for interest sake, on induction setup the gain was set to 71, but to reach same boost level (1.2bar) on stock air-box the gain had to be set to 74.

But re-fitting the induction filter and reducing gain back to 71 everything returned to normal as expected (1.2bar).

 

So the stock panel filter I can only assume is quite restrictive (as mentioned by some of the replies earlier).

 

On comparing the boost graphs (which can be overlayed with the Blitz SBC i-colour), I could see that it was turbo 1 curve that was really lazy on the stock air filter in comparison with the induction setup.

 

I'm pretty sure though, a faster flowing panel filter and the stock air box has to be the better set up.

Just need to find a good fast flowing panel filter before I give it another try.

(Any reccommendations anybody?)

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Hi AJI,

 

Are you still using the Power Enterprise Induction filter ?

 

Also, was the stock paper filter NEW or used ? (This will make a difference in my book)

 

I normally replace my stock filter once if not twice a year to keep it free flowing as they do turn black quickly and can become restrictive.

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