black cat Posted August 16, 2005 Share Posted August 16, 2005 sorry if this has been covered a million times, How much is a mid-de cat pipe (fitted) and what will it alter? bhp, sound, or nothing.?? plus will it have any adverse affects on boost pressure. Basically is it worth just having de-cat on its own or is it gona cost wadds to make it good.???? TT steve. Quote Link to comment Share on other sites More sharing options...
chilli Posted August 16, 2005 Share Posted August 16, 2005 I see you have a j-spec, normally it is recommended that you de-cat both cats and use a restrictor ring to put some backpressure back in the system. Not sure about just removing the second cat, but anything that reduces the back pressure can raise the boost on a j-spec, more boost = more power. Just ensure you stay at 1.2bar or below for a decent turbo lifespan... Quote Link to comment Share on other sites More sharing options...
tbourner Posted August 16, 2005 Share Posted August 16, 2005 Search BPU or look in the FAQs. Quote Link to comment Share on other sites More sharing options...
Pig Posted August 16, 2005 Share Posted August 16, 2005 so what about on a UK spec? im putting on a cat back. wanna decat as well. cant get boost control cause of insurance. Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted August 16, 2005 Share Posted August 16, 2005 What about decat on a UK? You'd need a boost controller to up the boost if thats what you're thinking of. Quote Link to comment Share on other sites More sharing options...
black cat Posted August 16, 2005 Author Share Posted August 16, 2005 boost controller aaaaaaaaaaaaaaa......... will 200 quid do it?? tt steve Quote Link to comment Share on other sites More sharing options...
Pig Posted August 16, 2005 Share Posted August 16, 2005 do i need a restrictor ring aswel? and is there a boost control i could remove if i had a crash cause insurance wont let me have one Quote Link to comment Share on other sites More sharing options...
Bobbeh Posted August 16, 2005 Share Posted August 16, 2005 You mean restrictor? That you wont need because you have to have the conroller to get the boost UP, its not like the JDM models that need controlling/taming if you will. Best be honest with insurance, who knows what sort of accident you could be involved in, for example if you're trapped in your car and cant remove anything or even disabled after and not able to to fiddle with your car! Whose to know what could happen. Quote Link to comment Share on other sites More sharing options...
Pig Posted August 16, 2005 Share Posted August 16, 2005 Im putting the sports exhaust on but am aware this is not going to make too much of a difference. Do u know if it worth while de-cating? Is there no way to increase boost with out a boost controller? Quote Link to comment Share on other sites More sharing options...
black cat Posted August 16, 2005 Author Share Posted August 16, 2005 this is getting a bit grim guys. tt steve Quote Link to comment Share on other sites More sharing options...
Nic Posted August 16, 2005 Share Posted August 16, 2005 boost controller aaaaaaaaaaaaaaa......... will 200 quid do it?? tt steve Steve, you shouldn't need a boost controller on your J-spec, Bobbeh was talking about the UK Supra which is a little different. Removing both cats on your J-spec should increase boost pressure significantly, as the cats are very restrictive. In most cases it is neccessary to fit a restrictor ring (simple plate with smaller hole in it) to keep the boost to below 1.2bar. Before increasing boost you should check the condition of your intercooler, if it is in poor condition it may not be up to the job. You will also need to fit a boost gauge, so you can monitor things. You will probably also need cooler grade of spark plugs fitting, to prevent misfire at high boost. To be on the safe side, it would also be a good idea to fit a higher flowing fuel pump (Walbro 255l/h or UK spec) and a new fuel filter (Toyota). Quote Link to comment Share on other sites More sharing options...
Nic Posted August 16, 2005 Share Posted August 16, 2005 this is getting a bit grim guys. tt steve Steve, Bob is talking about the UK car, which needs a boost controller, your J-spec shouldn't. Removing the cats on a UK Supra doesn't have the same effect, as removing them on a J-spec. On a UK Supra a boost controller is needed to raise the boost. On you J-spec removing the cats, will probably increase boost too much, which is why a restrictor ring in needed to bring the boost back down to a safe level. Quote Link to comment Share on other sites More sharing options...
Irvy Posted August 16, 2005 Share Posted August 16, 2005 i have just fitted both CW decat pipes and restrictor ring to my car heres the story so far i am now hitting .9 boost....my options are too increase the diameter of the restrictor ring to increase boost...in theory this seems good except that if i get the boost to 1.2 just now....when the cold weather comes along and i put the foot down...i could potentially see anything up to 1.5 with the dense cold air - definitely not good 2nd option is a boost controller as i can raise boost to a ceiling of 1.2 without it going higher...or should in theory! the other option is as follows....get the first cat removed and fit an envy pipe - its about 3" diameter as opposed to CW 2 1/2"-....this raised my car to 1 bar with the 2nd cat still in- this also meant i still passed an MOT. I did however change the plugs as this small increase did mean i needed the platinum plugs (as described in a previous plug thread) hope this helps Quote Link to comment Share on other sites More sharing options...
chilli Posted August 18, 2005 Share Posted August 18, 2005 For some reason I thought it was the second cat that was the restrictive one, am I mistaken? What option are you going for Irvy? Quote Link to comment Share on other sites More sharing options...
Nic Posted August 18, 2005 Share Posted August 18, 2005 For some reason I thought it was the second cat that was the restrictive one, am I mistaken? What option are you going for Irvy? 1st one nearest the engine is the most restrictive. Quote Link to comment Share on other sites More sharing options...
chilli Posted August 18, 2005 Share Posted August 18, 2005 ok cheers! So with just that one removed the car can still pass an MOT? Quote Link to comment Share on other sites More sharing options...
black cat Posted August 18, 2005 Author Share Posted August 18, 2005 some tests may pick it up. depends how good the second cat is, i dont know for sure but do apexi do a performance cat for the mid section?? ££??. tt steve. Quote Link to comment Share on other sites More sharing options...
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