zx 16v power enhancements

mrbump · Unread post by **mrbump** » 11 May 2005, 05:59

dear all,
I have recently bought a zx 16v 2.0 k reg (xu10?) for a friend for trackdays and am looking at cheap ways to get a bit more oomph from it.
We are going to replace the cat and exhaust for a bodgy straight through design and I was wondering if this will have any ill effects with regards to the o2 sensor reading to the ecu?
I know there is a few derivations of this engine (i beleive we have the 155bhp one) and wondered if an ecu swap will help matters at all? i think this one is 3 plug one - eg the emissions one.
Has anyone experimented with fuel pressures with an air filter?
If you have any ideas that you ever wanted to test, but were too worried to try because you didnt want to wreck your car - nows the time!
Remember this is a track car and any mods should be free or at least very cheap.
Any ideas at all welcome![}:)]
Cheers
Greg

citroenzx · Unread post by **citroenzx** » 11 May 2005, 14:26

you could always try one of those resistor things that you find people scamming on ebay, supposed to make the car run rich.
Remove the air filter and take the air in from as high as possible to prevent crap being sucked in to your engine also take as much of the interior out as you can.

VisaGTi16v · Unread post by **VisaGTi16v** » 11 May 2005, 15:13

Gut it. Easiest way to gain bhp/ton. Remove rear seats, door cards, carpet etc. If you do it properly it can all go back in afterwards. Ive taken 110kg off my Visa in total doing this although admittedly I have cut down doors, put perspex in and removed all soundproofing etc

macaroni · Unread post by **macaroni** » 11 May 2005, 15:19

Not sure about those cheap chips, likely to kill your engine after a few track laps, but the best and cheapest (free!) way to improve performance is to strip the interior.
You will be surprised how much weight can be lost by removing things like back seats, parcel shelf, trim, etc.
I saved 32kg on my 205 with some simple removals and if you then recalculate your power to weight ratio, you will see how much extra bhp you would have to find to match it and that would be more expensive.
Like you said, filter and cat removal is a good way to liberate about 5 bhp and make a good noise too. Cat replacement pipes should be available for your car and are quite cheap, they should also have a hole for the lambda sensor, if it requires it.
Also, make sure the engine is working as well as it should, ie make sure the plugs, leads, fuel filters and oil are renewed. Fairly obvious stuff, but can make a difference.
Hope this helps.

VisaGTi16v · Unread post by **VisaGTi16v** » 11 May 2005, 15:42

Yer re:engine make sure the 2 ACAV valves move when you rev it as they always break on that engine. Got a photo somewhere... http://homepages.nildram.co.uk/~visa/pi ... engine.jpg rev it and watch, they should both pull in

oscarloco · Unread post by **oscarloco** » 11 May 2005, 22:25

Try removing all unnecessary ducting in the air intake and placing an open element air filter. I put one on my car and it definetly revs better and feels more responsive along the induction noise that improved. If you want, I can send you pics.

mrbump · Unread post by **mrbump** » 11 May 2005, 23:49

hi,
already done the obvious stuff like interior and service. have positive pressure induction as well.
both acav valves are working, but am probably going to lock them in the short intake path position.
has anybody used a cat replacement before? any other fiddling required to get the correct reading from the o2 sensor?
cheers

Chrispy · Unread post by **Chrispy** » 12 May 2005, 02:54

Removing the cat will have 2 possible effects. The extra back pressure of having them on provides additional torque low in the rpm range. Removing it reduces this effect but will help engine breathing at higher rpm. On the track, high rpm is what it's all about. On the road, it's torque.
Get a proper ECU remap/ chip. DO NOT fit one of the resistors you see on eBay for 10p. They fool the ECU into shoving loads of fuel into the engine and cause bore wash. In warm weather your car will simply go bang. Also, if you have a lambda sensor then chances are this wont work as the sensor will correct the rich mixture.
Next thing is a decent induction kit with a cold air intake from behind a headlight or something. Hotter cams are a good idea but are costly and may give you a lumpy idle depending on how hot you go. After that my friend it's a turbo and a reduction in the compresiion ratio. Getting more BHP is never easy unless the engine is blown and even then it can be risky.

Chrispy · Unread post by **Chrispy** » 12 May 2005, 02:57

Oh, and as for the de-cat, make sure you get one with a screw hole for the O2 sensor. Removing it messes things up something rotten. A rich/ lean mixture means the engine is running less than optimally and possibly not outputting the HP it could. I've seen de-cats without this and all they do is backfire and pop and smell. Not good.