Exhaust system+manifold

Hi.I want to change the whole exhaust system and manifold on my bertone.
Can i run without any cat,should i need lamda simulator,MOT is not problem.
This is every day car,not track car.
The other mods will be,2.4 inlet manifold,ported TB,induction kit,tapped EGR.
The car is running on LPG,is that problem ?
the second lambda will need a spacer and not be working properly as you need to 'cheat' it in to thinking its working correctly.
the first lambda needs to be fitted as it should be to set the fuel mix.
Hello, just signed up so still getting to grips with everything lol but i have just fitted a new full exhaust system including a 4-1 manifold and 200 cell sports cat, my fuel consumption has rocketed i used to average about 27mpg but am now doing 18! also smells rather rich, their is no EML light which i was half expecting, will i be needing a remap to solve this problem
if you disconnect the battery for twenty minutes it will reset the ECU, this will help in the short term.

There are very few 'tuning companies' which can remap the z22se ecu, most just alter the fuelling within the factory permitted range. Courtenay can remap the ecu.
27 mpg is poor, and as for 18 well theres quite a few of us with superchargers getting better than that!
you may have some other faults such as coolant temp sensor, air inlet temp sensor or lambda sensor.
or even as simple as binding brakes and low tyre pressures?
Thanks for the info guys, the brakes are all fine, not even that old swapped for drilled and grooved, the tyres were all done days ago im leaning towards the dodgy lambda from other info i have read and because it is stinking of fuel,wouldnt this cause eml though?, also read about driving for 30 miles at under 2k revs for some reason?

Just gone out and disconnected battery to reset the ecu, how long will this help for? is their any figures i can get from sensors using obd2 to try help you guys diagnose my poorly coupe?

On a different note would like to thank you all on z22se as you have helped countless times in the past (y)
Just an update on the situation, more or less certain its 1st lambda, connected to ecu using bluetooth and torque app, and scanned for codes and their was a yellow code showing s1b1 running lean, cleared that went for a quick drive and got an eml, checked the code again and this time s1b1 was red, graphed s1b1 in realtime when car was up to temp and highest reading was 0.1v, after some more reading on the site came accross carls screenshots for lambda readings and at idle 1st should be 0.85v to 0.95v, will be back once lambda is fitted hopefully with good news ☺
some time sensors fail and dont put a code on at first.
when my cat decided to set its self free and take the second lambda with it for a new life on the oxford ring road, no code came up. even after 10 miles and a few stop starts.
same with inlet temp sensor and coolant sensor. voltage's changed but temp's stuck at -40*F :confused:
Hello, wow i would have immagined both of them cases throwing up eml instantly lmao, lambda has now been changed and all seems well, better than when i actually purchased the car, even with my slightly heavier than normal foot due to the full exhaust im averaging 33mpg and its still climbing.

Hopefully get my ported and polished throttle body on over the weekend, any significant gains or problems to expect?

Thanks again