My S4 Pod filter experiment conclusion.

[jerry]

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 £40 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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[LVC]

Interesting and well done for giving it a try - I wouldn't know where to start

[Nickj]

Always sound good in theory but often is more work to smooth motors out than it's really worth.
You loose an awful lot of the engineered in resonace by tossing the air box and it's usually difficult to get that back

[jerry]

To be honest I am more than happy with my bikes performance with the airbox ,smooth , powerful and good fuel economy , but wanted easier access for service and tuning and I like to experiment ,,

[jerry]

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 aribox lip under the radiator ,, tried glueing it ip and sealing but my plastics 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 .