I currently have a Sports cat and was thinking about just slapping a de cat on when i come round to map my car but my question is.... is it really worth it?

how much of an increase would be seen over a sports cat?

does anyone happen to have a before and after or has done research on the gains before and after fitting a de cat after a sports cat?

the major advantage i guess of the sports cat is i dont have to mess around come MOT time but how much power am i bottling up by not using a 3" de cat down pipe

p.s. I have a PPP sports cat down pipe for reference

 

sorry should have put this in the tech section, my bad

 

Slightly quicker spool up/torque....

I'd stick with a sports cat personally.... de-cat seem always to be the poor man's solution with minimal gains and MOT woe's every 12 months

 

hmm i aim for around the 360bhp mark come remap time, will i be all right with the 3" PPP sports cat? it wont be to restrictive?

 

What is your blob? a UK 2.0L with PPP?

 

its a Sti type uk, dont think it had the PPP package, but has full blitz exhaust, 3"mid pipe and PPP sports cat... currently remapped to around 320 i believe. getting some Harvey ported headers and up pipe and getting Duncan@raceDynamix to give it a remap.

I want around 360 but might be a bit of a stretch on the vf35... if it doesn't reach 360, a tdo5 might be on the cards at some point.

but i'm worried the sports cat will be restrictive?

 

For 360BHP, Andy Forrest recommends a decat.

http://www.andyforrestperformance.co.uk/58932.html

 

340 would be my guess..but Ask Dunc... he'll know what's achievable

 

and a 20g

 

dont worry my friend there is plenty of members on here with sports cats running circa 400bnp so you will be fine.

 

Ahh cool, as long as it doesn't bottle flow to much i'l just leave it in so i dont have to fanny around come MOT time... i will probably have to upgrade turbo but i'm sure once it's remapped that will sustain my need for power for the time being haha

cheers for all the info guys, much appreciated

 

Have seen 352bhp with the sports cat on a blobeye sti so it is possible.

Sports cats work very well and for the lower hassle come MOT time are worth losing 10bhp ish but you are extremely unlikely to hit 360 even with a decat except on rare occasions or exceptional cars. It is possible though so who knows...

 

cool cheers Duncan, after this coming remap i'l think about whether its worth investing on a bigger tubby

 

We will get the most from the current set up for sure, whatever that may be.

From there upwards it is a turbo choice question .. lots to choose from and depends on the ultimate power targets (and budget). be careful about going too big though as it can really change the characteristics of the car and quite often make it slower in the real world even though ultimate power is higher.

 

i have a sports Cat on my classic with blitz exhaust, had it up to temp for a short time at mot time and it would of failed emmisions if the guy didnt set the category to a non catt`d car, they were sky high for a cat`d car

maybe it wasnt upto hot hot temps but still,even with sports cat they fail on emmisions

 

Ah well that would be no good! i do wonder that if everything else was modded i.e. ported headers free flow up pipe, full exhaust etc that the sports cat would have a very very hard time keeping emissions down to legal limits.

guess all i can do is wait till the dreaded time comes round and see what happens and go from there, luckily its not for a fair old while yet

 

I think it depends on the quality of sport cat fitted and how well it is heat wrapped, the prodrive ones are boun d to be the best quality materials I would have thought, my wrx flew through mot with only a ppp sportcat downpipe.

 

hmm so mixed reviews, i guess every car will be different. thanks for the info though daz mines a PPP so fingers crossed it will be ok when the time comes round.

have you heat wrapped yours? and what other mods did you have at the time of MOT?

 

Typically a sports cat costs you upwards of 12 bhp.
340bhp from a VF35 with a full decat is a very good result IMHO based on DynoDynamic results at TEG and Scooby Clinic on cars I know.

 

I wish i could get it! LOL
The last RR day i had got my car at less than 300 bhp. You wont remember Harvey but we had this discussion when we met a while back.
You fitted me one of your up pipes and Bob Rawle mapped it again for me.
I cant bring myself to bother with RR again, I may be tempted by Tracktives as that is a hub dyno and at least i dont have to watch my car get tossed around and lurch all over the RR during the run! LOL

 

i was running 326 with a 3" downpipe with sports cat down to 2" the rest of the system on a classic

 

MaDaSS : I certainly do remember. My recollection there was a good performance improvement with much earlier spool? I think as a result of mapping your car Bob asked us to fit the special 3 bolt uppipe to his car.

The problem with comparing rolling road figures is that you need to find a consistant rolling road and then stick with it. There is no point comparing the results from one type of dyno, say Maha, with the results from a Dastek and then a Dyno Dynamics as they will all vary and not every dyno operator is meticulous to ensure the consistancy of results.