Anyone tried the sports cats available on ebay. Im looking at changing my decat to sports cat and looking online and ebay they range from £170 through to £600.

Im guessing the ones on ebay should be avoided and i should be looking at a name brand like cobra or miltek.

Anyone got any real word reviews of the cheaper type and should they be avoided.

 

It's an empty 304 stainless pipe.

Cant see any value in a brand name unless a sports cat or made froma better material.

I chose the cheapest i could find for my 140i and didnt have any issues at all save you cash & put towards other mods if you ask me

Platforms got to be old enough now that any fitment issues been ironed out.

 

Crap sorry i messed up i mentioned de cat, sorted what I wrote.

Its the cheaper sports cats I'm looking for info on not the de cats. I have a de cat and looking for a sports cat for my classic to be legal for mots and Road side checks.

 

I have yet to see or hear of anyone having a road side emissions check in over 10+ years of driving.

Been pulled over plenty of times even in my straight piped rediculously loud Blobeye Sti by traffics with no muffler or anything.

MOT time i just got a friendly mot tester although modern times things are getting tougher

I personally would go decat & get a V-Band setup underneath at an easy to access part of exhaust as close to turbo as possible to put my cat on for MOT time or for that moment the planets align & you are pulled for an emmisions check and told to recitfy it.

Such a setup wouldn't cost much more than the top branded sports cats.

 

i put a jap speed sports cat on mine , passed last mot no issues and no problem fitting it , it seemed well made , i would buy it again , if i had money to use then hayward and scott , 200£ v around 600£

 

Depends which cell your going for? I have a Ninja 100 cell sports cat on mine. Passes but needs a good warm up first.

Although my mot guy pointed out I've had a slight blow on the centre pipe the last few mot's which might not be helping. Why he didn't point that out before I don't know.

200 cell passes easier, but more restrictive.

 

Probably 200 cel. The japspeed ones are just over £200 so not a bad price. Quality im not 100% on though but have been looking and reviews seem ok.

 

showing your lack of understanding here, how do you think the performance will be affected by air flow devations?

 

By an insignificant amount that would be pretty difficult to measure across each individual decat....

They are all the same shape its not a manifold with multiple twists & turns.

Plus that was when thought he ment decat not sports cat

How much more will airflow be affected by a sports cat compared to decat......

If you believe the same diameter, same shape, same length of pipe will perform better with a brand name stamped on it you prob believe the SC range of turbos are unique hahaha

 

Mine is a Japspeed 200 cell 3inch and my MOT tester also says it needs a decent time to warm it up. I kept my Prodrive Cat just in case.

Cost me 240€ ,Workshop said it was bit tricky to fit unless you have the engine out. You cant rotate it past the bulkhead.

 

good luck with that then if its waht you think.

 

I think I can give a good example on the Japspeed v a full decat , Henrik and I have been comparing notes. His old 2.1 car (ex MalcomB) made 350bhp with all same mods as mine except using RCM headers ( mine are cast ported ) Martyn remapped me today to 343 bhp ( mine engine has 60cc less capacity ) So both cars produced very similar peak power on SC36 . Where I think a small difference exists is in low speed torque , while I was chating to Martyn , he suggested that a slightly higher CR would reduce that mine is 8,0 :1 MalcomB had his done at Enginetuner who normaly build 2.1s to 8.5 :1 . Given this , Same tuner / same RR it would seem that at least the level of 350bhp that the 200cell Japspeed is not significantly restrictive.

 

i read somewhere the difference between a sports car and decat is minor , the sti cats are not as restrictive as i expected , i also modded my air intake and have cut out the resonator box , you get a bit more turbo noise plus it seems to help flow

 

I bought cheap manifold for a non turbo and fitment wasn't great.

 

So if a 200cel cat doesnt make much of a difference

You think theres gona be anything noticable between the ebay decat & the branded.....

As long as same diameter ?

yea... gd luck with that too

 

Im actually thinking either japspeed and jetex system or going for a full cobra system.

 

I'm after a twinscroll 200Cell and would rather pay £200 Vs £600 but don't want to compromise on quality. Following closely

 

Good post and have been thinking the same to make MOT time easier and lower the noise as mine is very loud at full chat and also thinking a track day then becomes a whole lot easier.

Not jumped at the Japspeed as it does seem too low a price ! not sure why though.

Steve

 

Japspeed noise is hardly more than the Prodrive Sports Cat IMHO but I am still running the very decent Prodrive Back box.
I'm now at 330lb/ft 343hp on the Sc36/ (TD0516G) equiv

My Prodrive sports cat is available, can't see anyone driving down here right now though.

 

Robsy / others considering what is or is not restrictive. While a gas contained in any sort of vessel always exzerts pressure equaly to the walls containing it , then provided that the open area (cm sq ) of the Tube in which it resides is of the same diameter before and after the cannister containing the Cat . Then the sum area of the 100 or 200 cell openings must be at least the same or more than the area of the Input pipe. Thus any exhaust gas flow ( at least at slow speed ) shall not be impeded though a Pressure incline. Clearly then if an exhaust pipe downstream of the cat has an internal diameter of half an inch less than the upstream side , then no restriction will be caused by the body of the cat itself ( as is the case in my system wirh a Prodrive back box )

At higher gas speeds however any sudden change in direction will cause a pressure pillow to build up, and this can occur if the distance to meet with the cell is too short for the angle of deflection needed to balance the pressure drop. Thus a larger diameter cannister may not flow as well as a longer one with the same volume, a short bellmouth design with high flare angle to the Cat is therefore to be avoided coming from the turbo. The same of course applies to funneling the exiting gasses into the middle section on the way to the back box. Obviously the absolute volume of exhaust gas to be flowed will be a function of the engines capacity and its rpm times the compressed volume achieved by the turbo. Therefore any restrictive back pressure will first become evident at highest boost and highest rpm, and will be seen on the Dyno as a sharply dipping power curves. So before making a choice about a particular Sports Cat and its ability to flow any given volume of gas freely; So you really must ask at what Bhp level do I expect it to Perform , The higher the power output the larger the Cat volume and exhaust pipe Diameter needed. So is a 3 inch turbo back Cat restrictive ? The answer is at some point definitely yes. But if your driving on our roads then you will have to fit one that passes the MOT , the Japspeed 200 cell does so (after a warm up) on a mapped 2 liter WRX , no doubt others will too , but are likely to cost more.

 

I am pretty sure even with a standard cat that the cat needed to be warned up to pass an mot , the fsti only has one main cat in the down pipe no up pipe cat , also sometimes a cat in the mid section that i always delete , so what i am getting too a jap speed 200 cell sports cat come mot time is pretty much the same as a standard cat needs warming up , i understand cat deletes in the down pipe but in reality very little performance increase plus likely hassle with mot , i would rather just pass an mot with what i have fitted , chances of being stopped and checked on the side of the road are very slim

 

Clearly the mid section is a likely restriction as the external diameter of the cat is only marginally more that the pipe compared to the downpipes , hence why Prodrive threw it out on the PPP , also although helpful to reduce emissions keeping the third one in up pipe is lunacy as its capability to disintegrate and chew turbo impellers is a ticking time bomb and in any case sitting anywhere in the gas path to spool makes no sense for the tuner.. But Id be more careful in saying that "little performance is lost" while retaining a Cat in the DP , for sure lap times on high revving track cars will suffer. But for a road car yes for the most part you are not in the rpm range that you would notice it.

I guess to prove the extent of power loss where it does occur in the power band, Id have to get back on the Dyno with a full decat* and another map tweak, but experience is that the upper rev power band is where the greatest restriction occurs.
( that won't be happening as I like yourself must make the Sports cat compromise with a road car ) .

 

I'm interested and come to Plymouth regularly (once allowed). Had Scoob gearbox done at ET last year and dropped car off just before 1st lockdown ! LOL..bad timing as it was there for 3 months!

 

when litchfield imported the Fsti , there were either standard or two tuning options , the first tune was with the standard cat but a cat back system which was around 310bhp , the second tune was a milltek exhaust including a sports cat and it produced 330 , 20 bhp is not a lot but is a bit more and worth getting , the other plus side is reduced lag with a sports cat , which on the fsti is minimal as it’s a fairly small turbo so little lag any way , off the line the difference between the 310 and 330 is minimal even when you are up to speed it’s minimal , it may add to better mpg as it’s all flowing better so in the long run worth the initial outlay , i’m not sure if litchfield used a 100 or 200 cell , i would expect 200 , adding to this on the hayward and scott site , a decat on a 2.5 inch pipe v a sports cat 100 cell they say there is only a 2 bhp difference , so reading between the lines then reasonable gains expected from a standard cat going to a 200 cell cat , the tuner who mapped my fsti said there was improved flow with the jap speed 200 cell sports cat , a good map is a great improvement on a scooby and a sports cat on top a good addition , my monaro they did a tuning pack it was a collection of items not just one thing but the collection of all the items made the biggest difference , sports exhaust sports cats modified intake box and intake pipe and bigger maf plus a remap , it was ££ but produced 100 bhp on a n/a engine quite an achievement 😁

 

Send me a PM when we get let out , Im sure I can let it go cheap if you take time to come over. Shame about the Gearbox I had mine overhauled Sept 2019 at ET and got it back inside 3 weeks still noiser than Id hoped though.