Backbox + filters, SAFE ????

[neil_jdmr]

My car is standard with the exception of the hks suction kit and is running lovely. I have a shiny Nur spec backbox sitting grinning at me which im keen to fit as i think it may prevent the boost dropping off at high rpm\'s which Im told all standard cars do.
 
Ive been researching A LOT using this site and many of the US sites which have all said after hitting peak power/torque @ 6.5 k the boost will tail off and it caused by restrictions from the turbos back. ie the exhaust/cat etc.
 
I realise replacing the cat without a pfc is a big no no but will just fitting the backbox be ok?, or do i sit on it till i can fund/find a pfc. I really just wanted to fit the box for the summer, but if if i am risking det/knock i may aswell save up and get a midpipe/downpipe and de-cat at the same time as a pfc and just get the lot done when i save up the pennies.
 
Aside from the the boost dropping off the car pulls perfectly and holds a rock solid 0.8bar boost on both turbo\'s so i dont want to do anything that will spoil the fun im having in it atm.
 
 
Oh another thing my tyre sizes are 255 (rears) and 235 (fronts) on 17" wheels does this mean i have 17x9 and 17x8 respectively???
 
Want some new wheels too, Lord only knows where the money is coming from:Hammer  
 
Have owned a number of performance cars but have known nothing close to the addictiveness of the rotary:InLove  Im sold!!!!
 
 
Thanks Guys

[CharlieP]

Bump....I\'d like to know the answer to this too

[m4drx]

yes but these cars are all different.

I ran stock cat with BB & filters fine then ran stainless race cat with back box 3" fine then went fully decatted with Nurspec R (very very freeflowing) and i got MAJOR boost spike up to 1.1bar! :eek

i had a boost controller so wired it up correctly (as it was running pills before) and fine.

however i only went fully decatted after buying an apexi Pfc but i am running it on base map and ive done track days and all sorts with no problems, not running lean or anything.


hth


ps. congrats on the new car chaz nick told me.

[CharlieP]

Cheers, wanted to get some pictures up, but my computer doesnt like the memory card at the moment lol
 
Taken the rear wing, so looking pretty smooth at the moment  

[chrisJDM]

filters and back box should be fine but going any further i.e. decat is a no no without a different ecu and remap, fitting just the back box wont really give you any gans without doing the rest of the exhaust system, will jsut make it sound different

I recommend your next mod to be an apexi power fc and a mapping session