200 cel high-flow cats compared to stock!!
Discussion
Hi there
Anyone thinking of tuning a 997.1 C2S, here is the difference it makes to swap the stock cats to some high-flow straight pipe cats, from the likes of AWE or NHP:-
Car spec:-
997.1 C2S with 47,000 miles
Stock airbox, resonator section removed and capped off.
BMC panel filter
Silicone hose from airbox to throttle body
X51 manifolds
Centre radiator
PSE
Stock cats VS 200 CEL straight pipe cats
Softronic
You can see that the car with stock cats was making good power with just under 360BHP peak, this came mainly from the BMC panel filter and X51 manifolds as the softronic tune made little to zero difference at this stage.
Putting in the 200 cel high-flow straight pipe cats, gave good gains, also the softronic seems to help out much more here too as there is no losses in torque or power down low that could be felt on the butt-dyno and the actual dyno showed no losses either. Looking at 10lb/ft across the torque range with upto 30BHP gains at certain points in the rev range with 10+ BHP gain on peak power.
I did also try a de-cat X-pipe too, which gave even better results, peak of 390BHP, but the losses of power/torque below 4500rpm were huge, in the region of 40BHP/40lbft and the noise was horrific, so this was removed. So in short keep clear of X-pipe designs, they loose low-down torque and the sound track is not good and de-cats avoid all together!
Over next couple of weeks I shall be adding an X51 airbox with BMC filters, new spark plugs as current ones done 20k miles, GT3 throttle body and Eurocup carbon fibre plenum. Shall then be re-run on the dyno to see how they effect things.
Happy with the results!
Anyone thinking of tuning a 997.1 C2S, here is the difference it makes to swap the stock cats to some high-flow straight pipe cats, from the likes of AWE or NHP:-
Car spec:-
997.1 C2S with 47,000 miles
Stock airbox, resonator section removed and capped off.
BMC panel filter
Silicone hose from airbox to throttle body
X51 manifolds
Centre radiator
PSE
Stock cats VS 200 CEL straight pipe cats
Softronic
You can see that the car with stock cats was making good power with just under 360BHP peak, this came mainly from the BMC panel filter and X51 manifolds as the softronic tune made little to zero difference at this stage.
Putting in the 200 cel high-flow straight pipe cats, gave good gains, also the softronic seems to help out much more here too as there is no losses in torque or power down low that could be felt on the butt-dyno and the actual dyno showed no losses either. Looking at 10lb/ft across the torque range with upto 30BHP gains at certain points in the rev range with 10+ BHP gain on peak power.
I did also try a de-cat X-pipe too, which gave even better results, peak of 390BHP, but the losses of power/torque below 4500rpm were huge, in the region of 40BHP/40lbft and the noise was horrific, so this was removed. So in short keep clear of X-pipe designs, they loose low-down torque and the sound track is not good and de-cats avoid all together!
Over next couple of weeks I shall be adding an X51 airbox with BMC filters, new spark plugs as current ones done 20k miles, GT3 throttle body and Eurocup carbon fibre plenum. Shall then be re-run on the dyno to see how they effect things.
Happy with the results!
Edited by Gibbo205 on Sunday 21st April 17:13
Great results.
Replacement of the factory catalysers has always THE best way to get more power from the M97 3.8 engine (without internally modifying the engine) as the standard units are very restrictive. AWE 200-cell cats were the only mod that made an instant and noticeable difference to the 997S.1 I used to own. I never did back-to-back dynos on my car, but subjectively, there was a big difference starting at just over 4000rpm, peaking at 6000rpm and tailing-off slightly at the very top. Very similar to your own dyno plots in fact.
Add together the fantastic sound, the substantial performance hike, the not-unreasonable cost, plus the fact there are no real downsides - they even sailed through the MoT emissions tests - and 200-cell cats are an absolute no-brainer for anyone wanting more oomph from their 997S.1. They can even be removed quickly for dealer visits or resale purposes.
To anyone thinking about this mod - just do it!
Replacement of the factory catalysers has always THE best way to get more power from the M97 3.8 engine (without internally modifying the engine) as the standard units are very restrictive. AWE 200-cell cats were the only mod that made an instant and noticeable difference to the 997S.1 I used to own. I never did back-to-back dynos on my car, but subjectively, there was a big difference starting at just over 4000rpm, peaking at 6000rpm and tailing-off slightly at the very top. Very similar to your own dyno plots in fact.
Add together the fantastic sound, the substantial performance hike, the not-unreasonable cost, plus the fact there are no real downsides - they even sailed through the MoT emissions tests - and 200-cell cats are an absolute no-brainer for anyone wanting more oomph from their 997S.1. They can even be removed quickly for dealer visits or resale purposes.
To anyone thinking about this mod - just do it!
Edited by Ian_UK1 on Sunday 21st April 20:04
Ian_UK1 said:
Great results.
Replacement of the factory catalysers has always THE best way to get more power from the M97 3.8 engine (without internally modifying the engine) as the standard units are very restrictive. AWE 200-cell cats were the only mod that made an instant and noticeable difference to the 997S.1 I used to own. I never did back-to-back dynos on my car, but subjectively, there was a big difference starting at just over 4000rpm, peaking at 6000rpm and tailing-off slightly at the very top. Very similar to your own dyno plots in fact.
Add together the fantastic sound, the substantial performance hike, the not-unreasonable cost, plus the fact there are no real downsides - they even sailed through the MoT emissions tests - and 200-cell cats are an absolute no-brainer for anyone wanting more oomph from their 997S.1. They can even be removed quickly for dealer visits or resale purposes.
To anyone thinking about this mod - just do it!
Agreed best value for money mods on these cars for best bang for buck is definitely a BMC filter and 200 cel cats, they seems to give the best results on both sound and performance. Replacement of the factory catalysers has always THE best way to get more power from the M97 3.8 engine (without internally modifying the engine) as the standard units are very restrictive. AWE 200-cell cats were the only mod that made an instant and noticeable difference to the 997S.1 I used to own. I never did back-to-back dynos on my car, but subjectively, there was a big difference starting at just over 4000rpm, peaking at 6000rpm and tailing-off slightly at the very top. Very similar to your own dyno plots in fact.
Add together the fantastic sound, the substantial performance hike, the not-unreasonable cost, plus the fact there are no real downsides - they even sailed through the MoT emissions tests - and 200-cell cats are an absolute no-brainer for anyone wanting more oomph from their 997S.1. They can even be removed quickly for dealer visits or resale purposes.
To anyone thinking about this mod - just do it!
Edited by Ian_UK1 on Sunday 21st April 20:04
Other stuff like softronic, manifolds etc. help but they give only small increments.
Shall be interesting to see how the plenum, throttle body and X51 intake further effect things.
For those interested, here is a comparison between the Sport Cats and the full De-cat X-pipe, which also sounded bloody awful!
Now you can understand why I thought the car felt gutless between 2000-4000rpm, because of the 45lbft and 30BHP loss as the plot shows, though gains beyond 5500rpm not bad. Still with a 911 sports cats is the way as the engine design requires some back pressure.
Now you can understand why I thought the car felt gutless between 2000-4000rpm, because of the 45lbft and 30BHP loss as the plot shows, though gains beyond 5500rpm not bad. Still with a 911 sports cats is the way as the engine design requires some back pressure.
Martian O said:
I also have 200 cell cats and the difference to the stock ones is night and day. This is on a Turbo and they spool up even faster now!
Where did you source your BMC filter from in the end Gibbo?
For my X51 airbox, I found a company in Italy on Ebay with stock. But Design911 or Porscheshop generally stock them too.Where did you source your BMC filter from in the end Gibbo?
The Manthey K400 system for the 996 GT3 utilises a X pipe design and it works very well (sounds awesome too) I suspect the lack of cats was the issue that resulted in the loss of torque and Hp on your car, not the X pipe design. Did you map the ecu with the 200 cell cats and then again with the catless/X pipe set up ?
If the X51 manifolds are anything like the standard 996 GT3 manifolds, whilst I'm sure they're better than the originals, but my guess is there'll still be room for further improvement.
If the X51 manifolds are anything like the standard 996 GT3 manifolds, whilst I'm sure they're better than the originals, but my guess is there'll still be room for further improvement.
Slippydiff said:
The Manthey K400 system for the 996 GT3 utilises a X pipe design and it works very well (sounds awesome too) I suspect the lack of cats was the issue that resulted in the loss of torque and Hp on your car, not the X pipe design. Did you map the ecu with the 200 cell cats and then again with the catless/X pipe set up ?
If the X51 manifolds are anything like the standard 996 GT3 manifolds, whilst I'm sure they're better than the originals, but my guess is there'll still be room for further improvement.
Yes remap (softronic) on both.If the X51 manifolds are anything like the standard 996 GT3 manifolds, whilst I'm sure they're better than the originals, but my guess is there'll still be room for further improvement.
Hi there
Tonight I fitted:-
Carbon fiber plenum
GT3 throttle body (76mm upto 82mm)
X51 carbon fiber dual air intake
Installation was a bit tight but easier than expected, took my time to prevent any potential air/vacuum links. Made sure to disconnect battery etc. So ECU fully reset.
Connected back up, left for 30s so throttle body could sort itself out, started car and no idle issues, left it to idle for 5 minutes.
Went for a drive, throttle seems a little less responsive which is to be expected as at present air box has a pair of old stock paper filters in it and the right hand side intake does not have a hold cut yet in the decklid for cold air feed. Felt similar to the stock filter in the regular Airbox would do, as high flow panel filters really improve throttle response.
So jobs to do:-
1. Cut hole in deck lid so cold air feed works.
2. Fit performance BMC filters, due end of week.
3. Extend MAF wiring so can route maf cable neatly under Airbox and not over it.
4. Maybe buy shorter oil filler tube, as stock one is too long, but does fit.
5. Fit new plugs, current are 20k miles old.
6. Change oil to Millers Nano oil.
7. Go back to dyno.
A picture of course:-
Glad I did it myself, always more enjoyable, though only when it goes well.
Oh and finally the good point, no infact the sensational point, the noise OMG the noise, no word of a lie past 5000RPM it sounds like 10000RPM, sounds like a CUP car, I'd go as far as saying the noise in the cabin is GT3 beating. Seems to pull better too, but sure improve more with second hole cut along with fresh performance filters.
Tonight I fitted:-
Carbon fiber plenum
GT3 throttle body (76mm upto 82mm)
X51 carbon fiber dual air intake
Installation was a bit tight but easier than expected, took my time to prevent any potential air/vacuum links. Made sure to disconnect battery etc. So ECU fully reset.
Connected back up, left for 30s so throttle body could sort itself out, started car and no idle issues, left it to idle for 5 minutes.
Went for a drive, throttle seems a little less responsive which is to be expected as at present air box has a pair of old stock paper filters in it and the right hand side intake does not have a hold cut yet in the decklid for cold air feed. Felt similar to the stock filter in the regular Airbox would do, as high flow panel filters really improve throttle response.
So jobs to do:-
1. Cut hole in deck lid so cold air feed works.
2. Fit performance BMC filters, due end of week.
3. Extend MAF wiring so can route maf cable neatly under Airbox and not over it.
4. Maybe buy shorter oil filler tube, as stock one is too long, but does fit.
5. Fit new plugs, current are 20k miles old.
6. Change oil to Millers Nano oil.
7. Go back to dyno.
A picture of course:-
Glad I did it myself, always more enjoyable, though only when it goes well.
Oh and finally the good point, no infact the sensational point, the noise OMG the noise, no word of a lie past 5000RPM it sounds like 10000RPM, sounds like a CUP car, I'd go as far as saying the noise in the cabin is GT3 beating. Seems to pull better too, but sure improve more with second hole cut along with fresh performance filters.
To improve sound and feel even more, get a set of RSS engine mounts. Imo one of the best bang-for-buck mods you can do to any 996/7 (same part fits GTx/Carrera/turbo) - if what you're after is a more engaging drive that you can enjoy all the time (not just flat out). They're dead easy to fit too.
They transmit more noise and rumble into the cabin, and help give snappier gearchanges. No real downsides apart from some loss of 'refinement' - but that's just what some of us want.
Ken at 9E will sort you out with a set.
Agree with Slippy btw.
They transmit more noise and rumble into the cabin, and help give snappier gearchanges. No real downsides apart from some loss of 'refinement' - but that's just what some of us want.
Ken at 9E will sort you out with a set.
Agree with Slippy btw.
Ian_UK1 said:
Europipe???
Yes Europipe carbon fibre plenum, as plenums are rumoured to do nothing, I wanted one which was a copy of stock but allowed fitment of the 82mm throttle body and the Eurocup is perfect for that, though it is made from carbon fibre so helps with heat and weight.I never knew a Carrera could sound so amazing, the X51 airbox really is something else.
RadiusTim said:
Bit of a misunderstanding I think Gibbo...
Your plenum part is 'EuroCup GT' from Porscheshop, isn't it?
'Europipe?' referred to the exhaust in SlippyDiff's 996 GT3 picture.
You really should try those RSS engine mounts from 9E as well.
Yes sorry Eurocup GT.Your plenum part is 'EuroCup GT' from Porscheshop, isn't it?
'Europipe?' referred to the exhaust in SlippyDiff's 996 GT3 picture.
You really should try those RSS engine mounts from 9E as well.
Engine mounts sound interesting, also seen the RSS crank pulley, but changing the pulleys worries me as Porsche designed them all to work in harmony with each other and though to changing to a lighter/smaller pulley tells me down the road it could cause issues, engine mounts seem like a good idea though.
Second hole now cut by local garage.
Edited by Gibbo205 on Thursday 25th April 16:36
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