My S4 Pod filter experiment conclusion.

[jerryz]

 My S4  my pod filter experiment which i strated a couple of months ago  has been intersting but ultimately not a complete success , failings out weighed the benfits .

 I removed the air box and put 2  chinese  4'' K&N style  pod filters with 57mm opening over the ram air velocity stacks for the injectors . had to write some new PC3 maps to make the system work , a total of 5 new maps were required 

Even in normal thai temps of 85-90f  warming up to operating temp took much longer 15minutes  rather than usual 5.
 

 The results were interesting  to say the least ,,  the S4 fuel consumption to dropped  into low 30mpgs  with massive power surge  from  7- 9.5k  rev limiter  like 2 stroke power band  and also from 3-6k  which made the bike more like an old 2 stroker  LC350 on steroids , induction noise was evil and encouraged hooliganism with the right hand ,  it wheelies in every gear even when u dont want it too like at 120mph  in 6th gear on bumpy Thai roads but a nasty power dip at 6k which I could not dial out after trying 6 maps variations at that point   seems the airbox baffles are  doing something important  to air flow  at that point,  as gentle slow smooth throttle would let the bike run through from 3 -8 k with no glitch but a big handful would cause a sudden stutter at 6k  like hitting the rev limiter   , and then  a couple of seconds later whooof at 7k the after burner lit up the front end went all light and zoom off to rev limiter .




so going to put the air box back on as the bike is sweeter with my old custom PC 3maps Mk7b   and drilled air box   22  X 25mm holes  with K&N filter and restore smooth glitch free power  from 2k -9.5k and get back the usual 45+mpg  with  a little less drama , but still fun fun fun .
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Cost of this experiment was minimal  the pod filters cost me $50 the pair   , the biggest hassle to using standard air box is the little 6MM bolt under the headstock which requires loosening the radiator to remove , making a 5 minute chore into  15 minute job , not using air box makes access for TPS and throttle body adjustment and tuning  so much easier , but on balance the bike is a nicer  more practicable beasty with the standard albeit highly modified airbox  restored

Other people have also had similar experience with EFI 4 valvers  916,996 etc  and pod filters and even with dyno time its unlikely one can beat a proper plenum chamber  airbox on these models .


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[koko64]

Thanks for sharing. Very interesting.
I tried pods on my old M900 and went back to a modified airbox.

[Dellikose]

From my readings, it seems the most consistent platform (pods v. mod. box) is with the modified airbox. The box creates a more stable atmosphere for the engine to draw air from versus the pods out in the open.

Anyways, thanks for your experiment.

[jerryz]

AAAARRRRRGHHH !!!!

put it back to standard air filter and loaded old maps ,,,,,,,,, doh!!!! not running right still a massive dip at 6k ,,,look at old airbox which is suffering after 12 years of Intense Thai heat and UV the plastics are getting very brittle ,, the clip mounts broke of 2 years ago and its held together with Tie wraps to seal ,, but found a massive split along the front airbox lip under the radiator ,, tried glueing it  and sealing but my plastics welding  specialist says the box has degraded so much from UV its no good its letting a rogue airstrem into the box so i will have to source an new S4 lower air box next time I am back in Uk , this heat and UV degredation of plastics is a major issue in Thailand on older vehicle and other items .
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MONSTERMAN

[SpikeC]

Duct tape?

[jerryz]

temporatily yes duct tape will suffice  and I have ordered another airbox  off fleabay in UK which i will collect when I next visit

Thats if I can ride at all with my arma nd shoulder problems