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Japspeed manifold + unsilenced b-pipe

K

K20A-Jay

Messages
65
Hi guys,

First of all, I apologise if this has already been covered, but i couldn't see anything on here

I'm currently looking at changing my standard exhaust setup to a unsilenced b-pipe and installing a japspeed manifold (keeping the oem backbox). I have read that sometimes modifying your exhaust setup can cause your car to run lean

Does this only apply if I change/remove the cat? I haven't really got the spare funds at the moment to upgrade to K100/Kpro

Any advice would be much appreciated

Thank you in advance :)

Jay
 
Yup! Fitting manifold without a map will make your engine run very lean.

Get it sorted with a map, or just wait till you have funds and fit them together.

You could harm your engine too without map.
 
I personally think you will be ok. I upped the boost on my Evo 5 by quiet a considerable amount. I was also running an HKS filter. I ran it like this for a fair amount of time. Now we all know how fragile turbo cars are when run lean. Normally asparated cars aren't so critical. I also decatted,+4 branch and full system + green cotton filter on a C2 VTS, no problems.
Having said all that, you won't get the full benefit of you mods without a re-map.
 
K20s are very prone to knock if running lean. If the knock sensors are working correctly it will retard the ignition to prevent knock, basically cancelling out most of the gains of fitting the decat. You'll also get a check engine light as the sensors will be thinking there is a fault with the cat, you can get O2 sims/spacers to prevent this.

Needs mapping really. Kpro/K100 will also be able to turn off the secondary O2 meaning no check engine light.

Of course if the knock sensors don't catch all of the knock, bad news, engine gets too hot from the knock, things start to warp and that is when things go wrong.
 
Cheers guys

Going to hold off the manifold for now, wait another month or so until i can get some funds together. B-pipe is already ordered, but think i'll wait and get everything fitted and mapped all together
 
When I purchased my EP3 it had a full DC Sports exhaust (no cat) and an Injen CAI - unmapped.

It ran like a pig most of the time, very lean, plenty of pops and bangs.

I think you are doing the right thing waiting to get it all fitted at the same time.

However I have had different cars with aftermarket exhausts that ran fine without being set up.
 
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I think the k20a2 is just a very delicate setup managment wise, because its fine tuned from factory its not designed to tolerate such great differences as most cars

I wouldn't want to risk trashing it after only owning it for about a fortnight :lol:
 
Could you not get the ecu reflashed without it being on a dyno think its a little cheaper? Just depends what price range is.
 
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