Evening Gents,

Want some solid info preferably on those that have made catalyst changes, primarily because I do not want damage and secondly to save hassle on MOT day.

Hawkeye STi... has 2 cats.. one in the downpipe and a second one under the car.

I want the best performance from my Hawk STi but do not want the effort/cost of swapping the downpipe every MOT day.

I have heard I can get a decat downpipe and just bolt on the 2nd cat when MOT day comes, this avoiding the unbolting from the bellmouth/intercooler removal.

Can someone confirm that this will pass the MOT having only the 2nd cat on...

Cheers!

 

Best bet is to remove the second cat and keep the cat in the DP. You will see some performance increase removing the cat in the DP but given you're capped by the small TD04 turbo coupled with oodles of torque anyway, why bother

I run a sports cat in mine, but mine is an STi

Highly unlikely you will pass an MOT with the small cat, and if left in you will muller it anyway with the decat

 

My 04 Blobeye passed last year with just the 2nd cat no problem.

This year it had a Prodrive downpipe with the sports cat and no second cat. It passed fine this Saturday. I don't know the testers so there were no favours done!

No remap yet for either change.

 

53, mine is an STi and all, sitting at 298.5 last dyno, since then all I have done is put a H&S non res centre section and Scoobyparts Tornado 2 exhaust, felt a bit better from that alone.

Wonder what I would get from a 100 cell sportscat with panel filter.

 

You will already be Maxing out your TD04 turbo. Doubt you'll get any more without changing that first. I got the cobra sports cat downpipe on my 06 wrx. Good bit of kit, running well over 300 and passes mot no problems.

 

Sorry, missed that. Yours is sti? Should already be making more than that with the VF43 then.

 

Yeah buddy... So cobras are good then? yours a 100cell? guessing you have to have it warm for the MOT?

 

This is what I'm on now. My main reason was to avoid any messing at MOT time without choking the engine. Also spotted a road side emission test for the first time on Monday. If these become regular there could be a lot of de-cats getting prohibition notices

 

Likewise bud, I really dont like the thought of that awesome motor choking because of MOT standards.

But at the same time I cant be done with replacing the cats every year and risk damage to intercooler hoses and studs etc, its a chore..then there is roadside testing..

Wonder what the most someone has made from a 2.5 STi with a 100cel and filter...is 350 too optimistic!

 

Went for the more restrictive 200 cel and car still making good power with VF48 turbo. Have to get it warm but nothing daft and passes mot just fine. Was £225 for downpipe if I remember.

 

My turbo housing cracked, only running 1.3 bar and car still making 334bhp and 381 lb/ft with the more restrictive sports cat. Great car to drive on the road.

 

My bug STi was running at 360 bhp with a APS 3 inch system with sports cat on OE injectors and OE turbo. List was FMIC, RCM Headers APS Exh, uprated fuel pump, aeromotive FPR and a GEMS ECU. All I had to do was refit the OE ECU for an MOT, just had to tickle the revs to get it through. I always had to gun the car prior to MOT and get the emissions done on arrival. Where in scotland are you (might be able to make a suggestion by PM.)

 

What are they standard running bud? I should know this but dont...

Good torque figure! I always feel thats where it counts more than BHP.

Only thing is the EcuTek licence and remap, plus walbro bumping up the costs. I imagine itll be well worth it though!

 

Id love to get 360 as I have heard that is a very good figure combined with the weight in these cars to be a proper challenge for the rich toys.

Im up in the Highlands bud, Inverness.

 

PM on way.

 

360 you'll need a decat or an optimistic mapper with dyno mine made 335/375 on the sports cat but it could be pushed slightly further. )

 

360 bhp on 3 different dyno's. Changed the turbo and injectors to goto 400 bhp on the same exhaust.

 

Mine was 253 bhp standard when I had it rolling roaded. New bhp and torque makes it a great road car.

Doesn't cost any more to run after fitting walbro, turbo, exhaust, etc and mapping. Get same fuel consumption as standard car. Lol.

 

Brownpantsracing, do you use DSAutomotive that used to be G-Force Motorsport?

 

Used DSA rolling road couple of times but got Duncan Race Dynamix to map it on road and DSA dyno last time.

 

Also use Rich from FB Tuning. Top top bloke.

 

Mine was first done at G-Force then done most of work myself just taking to my mappers normal working base for re-maps.

 

They are ok at dsa. Useful being so close.

 

When i have asked questions they were very helpful. Last time I was there was to get the APS 3.5 inch de-cat exhaust. Always try to do the fitting myself if I can.

 

The other thing to remember is the new mot laws are that if it is supposed to have 2 cats 3 cats from the factory that's what you have to have test day and vosa are updating their data bases with the same info and will be targeting modified cars in road side checks this year according to the vosa guy that was checking my lorry over yesterday

 

I just read up on this!

Exhaust

A catalytic convertor fitted as original equipment but missing will be a reason for failure.




WTF???!! So if I get a single sport cat to replace my two cats then I will fail...

 

In theory, but you could fit a sports cat and an empty cat

That would do the MOT & the sports cat would enable you to pass a roadside test.

 

I like your thought process!

 

True but being a lorry driver and dealing with vosa regularly they won't fall for that one an old gadgy with his hammer will crawl around tapping this and that and soon pull you up on this .
It's the beginning of the end .the government seems to think all custom /modded cars are run by 18 year old hoddies street racing each other under the influence off drugs and booze while beating old grannies up .so in their eyes they are working towards stopping modded cars being run on the road .well thats my rant anyway