Discussion
Hey,
It likely won't pass the MOT. At most, I believe removing only the rear cat will get it through the MOT (as the PPP cars have this delete option I believe). Remove the others and it'll fail (was looking at this side of things myself recently). A remapping is also needed for any cat removal.
It likely won't pass the MOT. At most, I believe removing only the rear cat will get it through the MOT (as the PPP cars have this delete option I believe). Remove the others and it'll fail (was looking at this side of things myself recently). A remapping is also needed for any cat removal.
i agree they breath better but power difference is not much , it's the same as the centre exhaust delete , breaths better but much power difference ? but at least you don't have to remap , the downside of changing or deleting the main cat is mot time and cost of a remap plus cost of the part or the welding to delete it , on a 0 to 60 i bet there is little or no difference , how much £ for the cost v the bhp gained ? a sports cat makes a bit more sense but that's not cheap plus again remap and possible fitting cost , i have one fsti with and one with out both on the same boost i prefer the one with the cat to drive as it appears to have more ft pound but has slightly less bhp that is not noticeable
Interested in this also as I have a 2.5 forester XT and bought a prodrive sports cat second hand for it but can't decide to fit or sell it on. I am going to get the car remapped as coming from a remapped WRX it was a lot better with a map.
read up a little and was going to just go for
sports
K and N panel filter
NGK PFR7B spark plugs which are one stage colder (I did this on my supercharged MX5 and it made a big difference)
I also have a walbro fuel pump bought second hand but I don't think I will fit it as read mixed reports about reliability and I don't think I will need it for 260-270 bhp?
other things I was thinking about were a silicon Y pipe and a 3 port solenoid but I don't know if they are worth it/ make any difference at the power I am looking at?
Cheers Paul
read up a little and was going to just go for
sports
K and N panel filter
NGK PFR7B spark plugs which are one stage colder (I did this on my supercharged MX5 and it made a big difference)
I also have a walbro fuel pump bought second hand but I don't think I will fit it as read mixed reports about reliability and I don't think I will need it for 260-270 bhp?
other things I was thinking about were a silicon Y pipe and a 3 port solenoid but I don't know if they are worth it/ make any difference at the power I am looking at?
Cheers Paul
my fsti is on boost early it's around 2300 to 2500 it's on max boost , turbo is smaller so spools up quicker so not as much point in a sports cat , they say that small bhp increases are not that noticeable i don't notice the sports cat v standard cat , and i would notice it if it was different , fuel pump wise , mine at 75 k miles was beginning to fail on the fsti , one is on 150k miles the other on 95k miles and both are fine , i pressure test them about once a year , cat back is woth doing as you get the noise and it does flow slightly better , more bhp probably but not that noticeable as the sti fsti exhaust is quiet but works well , a remap yes , panel filter yes only because in the long run it's cheaper than buying new filters but again unlikely based on tests some time ago to give you more power , plugs are not a bad idea , on the wrx you may or may not need a pump as they flow less , i've had maps done on the fsti plus jdm wagon pumps were fine , adding to that the xt forester shares a number of bits with the fsti , hope that helps
OK cool
So maybe I will just get it mapped and leave the normal downpipe pipe cat in place. Or I could do the up pipe cat but I hear they are a bugger to get to and it's more money to get a replacement pipe? How much difference does a up pipe delete and sports cat make ? What is the difference in noise level? It's my wife's daily driver so can't be loud!
It already has the 3rd cat deleted and a back box.
Cheers Paul
So maybe I will just get it mapped and leave the normal downpipe pipe cat in place. Or I could do the up pipe cat but I hear they are a bugger to get to and it's more money to get a replacement pipe? How much difference does a up pipe delete and sports cat make ? What is the difference in noise level? It's my wife's daily driver so can't be loud!
It already has the 3rd cat deleted and a back box.
Cheers Paul
Hi Paul , the up pipe cats can fail at higher mileage, but i've not heard much about failures , i've changed mine on a ramp it was not a 5 minute job some number of hours later , plus cost of pipe and gaskets plus time taken, if i knew it was ok i would not have bothered , i thought mine had split it had not , don't think it would make a big difference on yours as not that restrictive , on the sti they can crack i changed mine there was no cat in it as sti don't have them , there was no difference for me but i was not loosing a cat , my opinion would be leave the down pipe cat alone as spool on the foresters is fairly quick , i think yours is a Td04 so i'm assuning boost comes in fairly low , a sports cat noise wise a bit more turbo noise , the centre exhaust delete gives you the noise plus a sports back box and better flow , if you are after sensible power a remap maybe but probably not plugs and maybe a pump depending on power and what the mapper says, a sensible tune and original pump will probably be fine , and then find a good mapper , i maybe wrong but 240 plus is easily achieved depending on your car spec , up to 270 to 280 with supporting mods but i think that's pushing it , it all depends on what you want to spend , it's always a pay off on reliability v power , i tend to keep it sensible as more power less fuel economy less engine life , i still get 32 to 35 mpg , as above i believe the block and heads are the same but internals are not , so whatever you do work with in your engine limits , an exhaust and re map would make a lot of difference but do exhaust cat back first , hope that helps
The plugs for the 2.5 are not the PFR7B's, you need the long reach versions....
https://www.ngk.com/product.aspx?zpid=9812
https://www.ngk.com/product.aspx?zpid=9812
many thanks, I just copied and pasted that from a forum I was reading so must have been for the 2.0
Cooop said:
The plugs for the 2.5 are not the PFR7B's, you need the long reach versions....
https://www.ngk.com/product.aspx?zpid=9812
https://www.ngk.com/product.aspx?zpid=9812
vxr2010 said:
Hi Paul , the up pipe cats can fail at higher mileage, but i've not heard much about failures , i've changed mine on a ramp it was not a 5 minute job some number of hours later , plus cost of pipe and gaskets plus time taken, if i knew it was ok i would not have bothered , i thought mine had split it had not , don't think it would make a big difference on yours as not that restrictive , on the sti they can crack i changed mine there was no cat in it as sti don't have them , there was no difference for me but i was not loosing a cat , my opinion would be leave the down pipe cat alone as spool on the foresters is fairly quick , i think yours is a Td04 so i'm assuning boost comes in fairly low , a sports cat noise wise a bit more turbo noise , the centre exhaust delete gives you the noise plus a sports back box and better flow , if you are after sensible power a remap maybe but probably not plugs and maybe a pump depending on power and what the mapper says, a sensible tune and original pump will probably be fine , and then find a good mapper , i maybe wrong but 240 plus is easily achieved depending on your car spec , up to 270 to 280 with supporting mods but i think that's pushing it , it all depends on what you want to spend , it's always a pay off on reliability v power , i tend to keep it sensible as more power less fuel economy less engine life , i still get 32 to 35 mpg , as above i believe the block and heads are the same but internals are not , so whatever you do work with in your engine limits , an exhaust and re map would make a lot of difference but do exhaust cat back first , hope that helps
yeah it is a Td04 I think and boost come in ok and it's doesn't seem as laggy as my 2.0 wrx (i.e it is smoother)I was reading that doing a sports cat downpipe gives extra torque but not a lot of power. same thread said that changing the plugs to one grade cooler made about 10bhp which sounds about right from what I found with my supercharged MX5.I assume the downpipe is quite an easy swap (a lot easier than the uppipe!) so I think I will throw it on before the map but leave the it on the standard pump. Not looking for massive power. Just a nice driving map with some extra grunt as it doesn't feel that quick right now!
many thanks for the advice
paul n said:
vxr2010 said:
Hi Paul , the up pipe cats can fail at higher mileage, but i've not heard much about failures , i've changed mine on a ramp it was not a 5 minute job some number of hours later , plus cost of pipe and gaskets plus time taken, if i knew it was ok i would not have bothered , i thought mine had split it had not , don't think it would make a big difference on yours as not that restrictive , on the sti they can crack i changed mine there was no cat in it as sti don't have them , there was no difference for me but i was not loosing a cat , my opinion would be leave the down pipe cat alone as spool on the foresters is fairly quick , i think yours is a Td04 so i'm assuning boost comes in fairly low , a sports cat noise wise a bit more turbo noise , the centre exhaust delete gives you the noise plus a sports back box and better flow , if you are after sensible power a remap maybe but probably not plugs and maybe a pump depending on power and what the mapper says, a sensible tune and original pump will probably be fine , and then find a good mapper , i maybe wrong but 240 plus is easily achieved depending on your car spec , up to 270 to 280 with supporting mods but i think that's pushing it , it all depends on what you want to spend , it's always a pay off on reliability v power , i tend to keep it sensible as more power less fuel economy less engine life , i still get 32 to 35 mpg , as above i believe the block and heads are the same but internals are not , so whatever you do work with in your engine limits , an exhaust and re map would make a lot of difference but do exhaust cat back first , hope that helps
yeah it is a Td04 I think and boost come in ok and it's doesn't seem as laggy as my 2.0 wrx (i.e it is smoother)I was reading that doing a sports cat downpipe gives extra torque but not a lot of power. same thread said that changing the plugs to one grade cooler made about 10bhp which sounds about right from what I found with my supercharged MX5.I assume the downpipe is quite an easy swap (a lot easier than the uppipe!) so I think I will throw it on before the map but leave the it on the standard pump. Not looking for massive power. Just a nice driving map with some extra grunt as it doesn't feel that quick right now!
many thanks for the advice
it's your call but i would cat back and map , the original pump maybe ok with that , go further you may need to change it , a map on its own makes a lot of difference it brings the fsti to life , i agree with siezed boot issue , i've had that before , i had an auto ? jdm wagon the box went the bolts caused a lot of problems , downpipe to sports cat is minimal difference , it's said you can only just notice a 20bhp increase , as you loose quite a lot of power through transmission , my fsti v the mrs fsti there is nothing in it mine has the sports cat and both run the same boost , mine slightly louder but that maybe the rest of the exhaust , mrs car more economical and nicer to drive , hers old shape mine is new , as mentioned above the turbos are different on the foresters so a downpipe change does not have as much effect due to quicker spool up any way, one of the down pipe change reasons is quicker spool up
[quote=tonyb1968]
The downpipe is normally the worst one to do as the bolts normally seize and then shear when you try forcing them off (even after lubrication), so it can literally take hours to do, but its also the best of the 3 cats so best retained over the other 2.[/quote
hmmmm ok.....any body want to buy a pro drive sports cat?!
Cheers Paul
The downpipe is normally the worst one to do as the bolts normally seize and then shear when you try forcing them off (even after lubrication), so it can literally take hours to do, but its also the best of the 3 cats so best retained over the other 2.[/quote
hmmmm ok.....any body want to buy a pro drive sports cat?!
Cheers Paul
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