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Bit of a DIY job but I'm happy with it



Cut out the cat from a good second hand front pipe and welded flanges to it

Welded flanges the downpipes too and made up a bypass pipe and flanged that as well



Now I can go back to the cat for the MOT and be de-catted for the rest of the year - 6 bolts and two gaskets and about 30 mins to change over

What do people think - I'll fit it later this week and let you know if it makes any difference to performance when it's de-catted

can't see the image from work, but I'm sure it looks like a good job!

you got that spare ECU yet? let me know how the de-cat performs....

david burton wrote:can't see the image from work, but I'm sure it looks like a good job!

It's not a bad job at all.....

david burton wrote:you got that spare ECU yet?

I bloody wish - becoming a bit of a mission now

david burton wrote:let me know how the de-cat performs....

I think it may help the engine breathe a bit better and stop it feeling so strangled but it needs the breathing improved on the inlet side too to match (oh and a induction kit doesn't meet the requirements!!!)

Just disconnected from VPN so I can see it now - looks superb. A nice idea. very neat indeed. Was it a pain to take the exhaust off the manifold?

you going to get the dremmel on the intake side of things then? or have you already done that?

david burton wrote:Just disconnected from VPN so I can see it now - looks superb. A nice idea. very neat indeed.

I bought the complete 2nd hand downpipe and cat off ebay for £10 so this was easy to modify at my own pace

http://cgi1.ebay.co.uk/aw-cgi/eBayISAPI ... 4570208138

Had a mate in another car club I'm in pick it up for me and then collected from him it at a meeting we both attended

I also wanted the cat to be easily replaced for MOT's etc

david burton wrote:Was it a pain to take the exhaust off the manifold?

It's only a 3 bolt fixing to the manifold and I've had mine off before cos the flexi joint was broken and I had to repair it - the idea was to offer them as an exchange but cos my old frontpipe is a bit of a bodge after the flexi joint split!

david burton wrote:you going to get the dremmel on the intake side of things then? or have you already done that?

No nothing like that - Have investigated boring out the std TB but there isn't enough meat in it so have the chance to buy a 1.6 TB so just weighing up the pros and cons..... might not fit, may be same size etc etc

Good job m8! Looks nice, and I'm absolutely sure you'll notice an increased in enginepower, a cat decreases the enginepower by approximately 8%, so that shouldn't be hard to notice would it?
And the cat works as a muffler for your exhaust sound.....

Have fun with it!

just make sure u dont get caught by one of those random emitions tests, but considerin how cold it is i doubt the rozzers will b out that much lol

OMEGASUPR3ME wrote:just make sure u dont get caught by one of those random emitions tests, but considerin how cold it is i doubt the rozzers will b out that much lol

Decatted all my other cars - been stopped before but only once have I been issued with a VDRS - change it back to cat take to MOT test station pay £6 get form stamped come back home and put the straight pipe back!!!

Rest off time - they are looking for serious polluters and don't even notice!!!

thats allrite then

did they stop you for any other reason apart from the idea you might not have a cat?!

david burton wrote:did they stop you for any other reason apart from the idea you might not have a cat?!

Nah - was just a spot check on everybody going down the road

- I could have argued the toss on the car (93L plate 3.0 24V Senator) I was in as it had (* well actually it didn't but it's a long story and a bit wafty) an engine swap from an earlier car pre 92K which I had the documentation to prove - so I didn't even need to put the cats back - they just did an emission check at the garage and stamped the form!!

*It's a well known dodge for certain cars made with cats before the law was effective (ie 1990 - 1992) but continued to be made after law on cats was effective

Basically it involves creating a paper trail that can prove that the engine has been changed from an earlier car pre-cat law and put in a car which is post cat law.

I now have a photocopy of a log book for a car long since scrapped which has the engine number for my L reg Senator down as it's engine number

I take the car for an MOT and they say cat test - I say Nope..... engine has been replaced - here is a copy of the log book for the car the engine came out of - it clearly shows the engine number is same as the one in my car and they don't cat test it!!!

The engine has actually never been changed what I did before I scrapped the old senny was send of the log book with my L reg engine number as an engine change

It came back all changed - I photocopied it and sent it back when I scrapped the car shortly afterwards

like I said a bit wafty and a bit involved but worth it

Haven't had to do a computer linked MOT yet so we will see if it works with that too!!!

Fitted it now.........

Initial impressions

- revs cleaner and picks up better

- slight improvement in pull even in the higher gears

- Exhaust note slightly louder (not antisocial just crisper)

- engine is definately happier to rev above 4000 rpm

Early days but it seems a fair bit better - maybe 4-5 bhp better

Only negative comment is hard to describe but there is a segment of throttle opening that I have always known was a bit flat and it's accentuated it - not by much but definately more noticable now

When you are around 2/3 - 3/4 throttle in 4th or 5th if you lift off it seems to pick up better if you bury the throttle it also seems to pull better

I think this will be a deliberately engineered hole in the fueling map for emissions or noise - and bloody annoying!!!

some lovely diy there bstardchild! i like!
I just spent over 300 for a stupid s/s ex manifold and decat front pipe. it was a stuupid decision i know i paid a hellalot for it. but it will make the engine bay look nice. and oh, ffs on mot i have to remove the whole thing!! LONG!!! i will post a pic of my car soon hopefully with the manifold (still hasnt arrived )an ill tell u if it makes any difference.
Steve

just read your last post, i have flat spots in those places too, noticable on motorway! Do you have an induction kit on your car ?

skyline.99 wrote:just read your last post, i have flat spots in those places too, noticable on motorway!

They will all have it - it's in the ECU maps I am sure

skyline.99 wrote:Do you have an induction kit on your car ?

nope bad for power unless you buy something quality like a BDA and then it's almost an airbox anyway!!!!