MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: markc on June 26, 2010, 04:08:43 pm
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Hi guys,
I've seen the pic on another post of one smashed out with a hammer, is it worth for doing for power gains, or driveability ? Are there any possible negatives to this,......... MOT failiure, error lights/codes etc
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this is a quote from my tuner with reference to me smashing out mine.
Removoin the pre-cat helps quite a bit, it significantly lowers the exhaust back pressure, so it helps to keep the EGT's at reasonable levels. My philosophy is safety first, I try to keep EGT's below 1000C and keep knock protection in stock levels.
and this is about the reason a precat is used and with future MOTs
Correct, pre-cat helps cold start emissions. A three-way catalytic converter found on the modern engines require a certain temperature before it actually becomes a catalyst. "pre-cat" as close to the combustion chamber as possible warms up quicker, which helps to burn unburnt hydrocarbons after start.
MOT emissions test isnt a problem after you remove the precat.
When a new car is type certificated, you're required to run an emissions cycle to prove the car is acceptable within EURO3/4/5 or whatever.
On this cycle, the car is run in a dyno with a "plastic bag" in the exhaust pipe. You run the car to a certain norm, and then open the bag and smell whats in there...
That test includes a cold start (which is actually the most important part on the test, because most of the "bags" fill up during this part), some city runs and accelerations to highway speeds.
From this test we get the data known as combined/city/highway mileage and the CO2 emissions. Thats why manufacturers try to cheat as much as possible on these tests. For example, regulations dont specify brakes on these tests other than brake calibers, discs and pads. Thats why some manufacturers use springs to keep pads off the discs during these tests. In the industry, this practice is called "cycle beating" Also they use the smallest allowed wheels/tires on this test (for example, Volvo has specified smaller tires than you can actually buy)
So, thats why we have a pre-cat on these cars. The main cat is enough for MOT pass when its hot enough (normal operating temp). Two cats only help in post-start treatment.
im expecting to get a good increase from this, just by looking at the pictures of it, you can see that the exhaust gases leave te turbo and hit a wall of catalyst material straightaway. if you remove that you speed up the flow of exhaust gases and you will defionately get gains, more so if you get a map tweak to utilise the extra flow
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Thanks Sy, :happy2:
I take it there is no seal to be replaced or anything when fitting back together, just bolt back up ?
I am mapped yes, I cant adjust it though. I will have to have a word with my tuner.
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the exhaust it self doesnt get taken apart. you just take it off the car hit the CAT material with a hammer so it shattersm make sure there are no bits left in the downpipe nd put it back on. i think the ecu will adapt enough to make this worthwhile
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Get rid of that pre-cat. :happy2:
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I removed my precat at the weekend on my (BWA) engine) Octavia vRS TFSI running the original map. The EPC light came on today, oh joy!!
Anybody else had this problem? I am getting the fault code read tomorrow.
If the fault code is caused by the precat removal can a remap remove this problem?
It could just be a coincidence but I doubt it.
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I have now been running without a pre-cat for 2 weeks (on the standard map) and the car runs fine without any engine lights. The EPC light I mentioned above was for something else and was totally unrelated to the pre-cat removal.
It's difficult for me to say if I have noticed any difference in performance due to the pre-cat as I fitted a Neuspeed intake, SFS Intercooler hoses and a rev d diverter valve at the same time as removing the pre-cat.
The car definitely feels perkier and sounds better after carrying out those mods though :evilgrin:
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Bringing up this old thread.. :innocent: What tools did you use in clearing out the cat and did you have any issues in doing this? Did you replace the exhaust seal to turbo?
And has anyone else done this, any more experiences with the power gains and how the exhaust note changes? Im thinking about doing the same for my BWA golf as I want to keep the stock appearance.
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Since this original thread I am aware of a few members on Briskoda removing the pre-cat on their vRS's, mine will be coming out when the car is next serviced. I have a couple of spare exhaust/turbo seals but tbh as they are metal they probably won't need replacing (they're only a few quid anyway), to remove the cat material you only need a hammer and chisel, the DP will need to be off the car to make sure you remove all the material, if you plan on doing it yourself this may help in the removal of the DP -
http://briskoda.net/forums/topic/124442-tfsi-downpipe-fitting-guide/page__p__1561519__fromsearch__1&#entry1561519
I was going to complete the job myself, but I figured for the minimal cost to pay my mechanic and the likely hood the bolts being seized I would prefer that he had the headache! :grin:
Regarding power gains, I think reports show that the turbo spools significantly quicker which should convert to a few extra torques, apparently the exhaust note will deepen under accelaration but beyond that no real difference.
HTH, Lee.
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Thanks for the info! I also found the other thread on this forum that had pictures of the smashed cat. Im going to be doing this myself and there are quite good DIYs available for this, heres one done on Golf:
http://www.golfmkv.net/blog/archives/20#
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The advantages are well known. Worthwile mod for remapped engines.
The disadvantages:
- ''smell'' when engine is cold
- louder noise, (very little) drone
- one hour of work (+ risk of braking bolts)
- illegal
I placed the DP upside down to prevent dirt polluting the (main) cat.
Then I used hammer and chissel and at least a steel brush.
TAKE CARE NOT TO DAMAGE THE OXYGEN SENSOR (or remove it) !!
I used new seal and nuts.
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How would this compare to a full decat?
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The advantages are well known. Worthwile mod for remapped engines.
The disadvantages:
- ''smell'' when engine is cold
- louder noise, (very little) drone
- one hour of work (+ risk of braking bolts)
- illegal
Has anyone actually broken bolts (or nuts) when taking the downpipe off? I picked up a couple of rust penetrating sprays yesterday to ease those.
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The advantages are well known. Worthwile mod for remapped engines.
The disadvantages:
- ''smell'' when engine is cold
- louder noise, (very little) drone
- one hour of work (+ risk of braking bolts)
- illegal
I placed the DP upside down to prevent dirt polluting the (main) cat.
Then I used hammer and chissel and at least a steel brush.
TAKE CARE NOT TO DAMAGE THE OXYGEN SENSOR (or remove it) !!
I used new seal and nuts.
Is it? Cold start emissions testing is not currently part of the UK MOT test......
@JMP - Also have a look here - http://briskoda.net/forums/topic/197778-pre-cat-removed/ :happy2:
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I have now been running without a pre-cat for 2 weeks (on the standard map) and the car runs fine without any engine lights. The EPC light I mentioned above was for something else and was totally unrelated to the pre-cat removal.
It's difficult for me to say if I have noticed any difference in performance due to the pre-cat as I fitted a Neuspeed intake, SFS Intercooler hoses and a rev d diverter valve at the same time as removing the pre-cat.
The car definitely feels perkier and sounds better after carrying out those mods though :evilgrin:
Made the mistake I do every time. Want to feel the difference of a specific mod but do them in bulk every time as it's usually more cost effective
Would certainly imagine removing the pre cat played a part in the improvement felt. Car's not ussually MOTd at cold start anyway :smiley:
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moderately tempted to have a go at this myself today, however I'm a bit concerned about breaking the turbo bolts........ :scared:
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My car has just sailed through another MOT emissions test without the Pre-Cat.
If you are DIYing this mod here are a few tips:
- Make sure everthing is cold.
- Spray some WD40 on the turbo nuts and the 1st Lamda sensor.
- Remove the 1st Lambda sensor before undoing the turbo nuts.
- Ramps or axle stands or car lift needed.
- New turbo nuts and the Gasket come to about £10, you might as well change them.
On a different note how much is Cat material worth at a scrappy as I have 2 Cats worth lying around somewhere?
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My car has just sailed through another MOT emissions test without the Pre-Cat.
If you are DIYing this mod here are a few tips:
- Make sure everthing is cold.
- Spray some WD40 on the turbo nuts and the 1st Lamda sensor.
- Remove the 1st Lambda sensor before undoing the turbo nuts.
- Ramps or axle stands or car lift needed.
- New turbo nuts and the Gasket come to about £10, you might as well change them.
On a different note how much is Cat material worth at a scrappy as I have 2 Cats worth lying around somewhere?
Good info Bogster.......
Regarding value of the cat material, it will depend what car its from, BMW and Mercedes use far more precious metals in their CATs, tbh though I'm not sure a scrappy would be interested in the raw material, but no harm in asking.
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Pagey if both your vrs and golf are diesels they don't have turbo bolts its just a clamp on the turbo to DP :happy2:
Darren
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Pagey if both your vrs and golf are diesels they don't have turbo bolts its just a clamp on the turbo to DP :happy2:
Darren
The Golf is a soot chucker, but the vRS is a 240bhp stage 1 petrol powered hearse......... :laugh:
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Pagey if both your vrs and golf are diesels they don't have turbo bolts its just a clamp on the turbo to DP :happy2:
Darren
The Golf is a soot chucker, but the vRS is a 240bhp stage 1 petrol powered hearse......... :laugh:
Thats different then :grin: good luck with the studs mate :happy2:
Darren
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I just finished mine, intake is still off so I didnt drive it yet. Hopefully its all ok :happy2:
It was a bitch to do since I couldnt raise the car very high. So crawling under the car and trying to manouver around took me over 3 hours. If you can get car on a real lifter this is quite easy task.
The turbo nuts came out easily but I had problems with the clamp that attaches the downpipe to catback. The other bolt was so rusted that I couldnt get it off. So I had to cut it and replace with new ones. I reused all other bolts & nuts and also the turbo seal as I didnt have a new one. Hope its still ok. I didnt remove the 2nd lambda during the operation as it wasnt really necessary.
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I just finished mine, intake is still off so I didnt drive it yet. Hopefully its all ok :happy2:
It was a bitch to do since I couldnt raise the car very high. So crawling under the car and trying to manouver around took me over 3 hours. If you can get car on a real lifter this is quite easy task.
The turbo nuts came out easily but I had problems with the clamp that attaches the downpipe to catback. The other bolt was so rusted that I couldnt get it off. So I had to cut it and replace with new ones. I reused all other bolts & nuts and also the turbo seal as I didnt have a new one. Hope its still ok. I didnt remove the 2nd lambda during the operation as it wasnt really necessary.
Nice work fella, look forward to hearing how you find it................how high did you get the car, and did you use axle stands or ramps?
Regarding the O2 sensors, could these not just be unplugged leaving the sensors bolted in to the down pipe?
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Nice work fella, look forward to hearing how you find it................how high did you get the car, and did you use axle stands or ramps?
Regarding the O2 sensors, could these not just be unplugged leaving the sensors bolted in to the down pipe?
I used axle stands on the front, so not very high. To remove the downpipe of the catback you really had to go pretty far back which was a bit problematic.
Well its easy enough to remove the first lambda. I would take it out because when you start smashing the cat out, it will most likely gather a lot of dust/debris. And I didnt see where the connector for 2nd lambda was, so I just left it in. It had enough wire to be able to work on the dp.
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I drove the car today and did about ten 3rd gear 80-120kmh pulls with 10Hz GPS + race chrono in my E7. Previously I have been hitting about 3.4s (best 3.36s). Now with decat average went down to 3.2s (best 3.16s). I did have different fuel then last time, I have now 98 and previous runs were with V-power so numbers look good. 0.2s might not sound like a lot but it does take a lot of power to get that down. There is clearly more power now.
The exhaust sound didnt change much. Change was hardly noticeable.. Lets see if I notice it more in daily driving. Car does seem to be reacting quicker now to gas pedal presses and breaks 2nd gear traction very easily.
I will be installing S3 cooler + oettinger turbo outlet kit next, hopefully I can get the 80-120kmh time under 3s when these are finished.
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Good results there, all academic for me now as I have secured a deal on a miltek dp/sports cat! :happy2:
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I did mine a while ago though I'm confused about the Turbo Bolts?
I literally took out the inlet bolts......just behind the actual engine....
When this was off the pre cat was right inside.
Are these the bolts you're talking about?
Also is removing the pre cat anywhere near a new downpipe for Stage 2? What's the differences? Thinking of having the Cat removed and straight pipe put in which can be swapped at MOT time. Would this substitute a full Milltek for example?
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I did mine a while ago though I'm confused about the Turbo Bolts?
I literally took out the inlet bolts......just behind the actual engine....
When this was off the pre cat was right inside.
Are these the bolts you're talking about?
Also is removing the pre cat anywhere near a new downpipe for Stage 2? What's the differences? Thinking of having the Cat removed and straight pipe put in which can be swapped at MOT time. Would this substitute a full Milltek for example?
If you remove the OE Cat in favour of a straight pipe (so decatting it) you will achieve the same as fitting a Milltek or similar down pipe, perhaps the performance will be slightly less due to the diameter of OE pipe which iirc is 60mm vs 70mm on the milly and 75mm on a pipewerx. You will need stage 2 software though and it will through up a CEL (stage 2 will sort this).
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I have done this on my Octy VRS and had Shark tweak my Stage 1 map over the weekend. I also fitted the SFS boost hoses and will be fitting a K&N Typhoon intake soon I got for a very reasonable price from a fellow forum member. Once done I will post up the results of the dyno run on the 17th October at Shark. With just the tweaked map, pre cat and sfs hoses the car really flies. It is effortless when accelerating and I can easily return 45 mpg on motorway runs.
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Is the SFS hose the same part as the Neuspeed ones? What's your thought on it?
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I noticed a nice improvement also in my fuel comsumption and the car just rolls so easy when your off the throttle.
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Is the SFS hose the same part as the Neuspeed ones? What's your thought on it?
My thoughts are the SFS hoses are much better as each hose is one piece and not in tiny sections like OE pipes. I had the neuspeed hi flo intercooler pipe and the SFS hose is wider even though it has a slighty squashed side in it to avoid the radiator fans. The turbo to i/c pipe does not have that bend in it and is a straight pipe, so flow should be quicker. The hoses are made from very thick silicone so build quality is top notch and since fitting them the engine revs and pulls so much easier. Its given the engine more grunt over the whole rev range. All in all they are expensive but worth it. I paid a lot less as I purchased them through here from a top bloke :happy2:
Matt
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Me and a friend had a go at this today, started un-tightening the 1st bolt (one you can see from engine bay) felt real tight, we tried WD40 (left for 10mins) still felt tight.
so heated up with blow torch, got a few turn out of it but still was really tight, my mate said it feels like itmight snap....i have heard a few people mention this
Anyone have a link to get a replacement bolt and seal kit?....or just buy straight from VW
Thanks guys
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I use a wire brush on them for 2-3 mins add plenty of duck oil and if they go tight just keep going back and forth.
Must have undone 400+ of these nuts and only ever had 1 snap (on a 2 month old Audi TT which was odd :confused: )
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I use a wire brush on them for 2-3 mins add plenty of duck oil and if they go tight just keep going back and forth.
Must have undone 400+ of these nuts and only ever had 1 snap (on a 2 month old Audi TT which was odd :confused: )
Duck Oil? Never used that...WD40 no good for this job. Where can i get duck oil?
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http://lmgtfy.com/?q=Duck+Oil
http://www.debgroup.com/uk/products/selector/cleaning/swarfega-duck-oil
http://www.amazon.co.uk/Duck-Oil-SDO5L-Service-Spray/dp/B000Y8J8I8
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http://lmgtfy.com/?q=Duck+Oil
http://www.debgroup.com/uk/products/selector/cleaning/swarfega-duck-oil
http://www.amazon.co.uk/Duck-Oil-SDO5L-Service-Spray/dp/B000Y8J8I8
bit expensive for one job...any thing similar that is cheaper?
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So i finally got arounf to removing my pre-cat with my mate today. And wow, what a difference. For 2 hours labour, you wont get a better mod.
Bit of a ball ache removing all the bolts (used 3 in 1 penatration oil form Halford - worked awsesome on the rust)
once chipped out and stapped back on. started it up and straight away got a really nice burble on down revs. Took it for a spin, cant believe how more responsive it felt for a such a small cat removal.......Just need my re-map now :pomppomp:
Find some quick pics below:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fk489%2Frocketrossuk%2FIMG_0517.jpg&hash=255f9ea0a957b036ad015f98ecdd9318306c85a2)
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(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fk489%2Frocketrossuk%2FIMG_0515.jpg&hash=4ca51ce2294490742f83bc9aea1e8e7b636e0b05)
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(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fk489%2Frocketrossuk%2FIMG_0518.jpg&hash=4124476409105809056ef77ac08386581a371768)
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Top class bodging there Ross!
Your findings are he same as most customers of ours that ave this done or DIY it, really worthwhile budget modification.
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Top class bodging there Ross!
Your findings are he same as most customers of ours that ave this done or DIY it, really worthwhile budget modification.
thanks to your great help and advice :drinking:
Sorry to take that bit of extra money off you when i come see you.....still getting my map with you, hopefully within the month, cant wait :party: :party: :party:
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Still not sure if i'm quite brave enough for this mod yet!
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Still not sure if i'm quite brave enough for this mod yet!
Easy as pie mate, just set a side a max of 3 hours (just in case), and just make sure you have the correct tools and you will be fine.
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I'm planning a pre-cat removal 'groupbuy' on the Dutch GTI forum (because I know a good company/guy that wants to remove them for a very good price, included new gasket).
I've heard that sometimes the engine light goes on, especially with cold weather/cold engine. Is this true? Who has experienced this problem (with a stock mk5 GTI, only ABT remap)?
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I've run the pre-cat delete for some time now, and never had a warning on the dash. Stock or Stage 1 map. Removing that pre-cat brick wall really helps the turbo out I feel, lowering the turbine temps has gotta to be worthwhile for longevity.
For those wanting to do this, just make sure you get some penetration oil / spray - job is tonnes easier on a lift :)
Grab a new gasket too, think they are about £4-£5 from VW.
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I've run the pre-cat delete for some time now, and never had a warning on the dash. Stock or Stage 1 map. Removing that pre-cat brick wall really helps the turbo out I feel, lowering the turbine temps has gotta to be worthwhile for longevity.
For those wanting to do this, just make sure you get some penetration oil / spray - job is tonnes easier on a lift :)
Grab a new gasket too, think they are about £4-£5 from VW.
So you've never seen the engine management light? Also no with these winter-temps?
So no downsides for this mod?
Have you also noticed a better fuel consumption?
What's the most noticeable? -> The quicker/better gas response? The sound? The fuel consumption? The bhp?
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To be realistic any improvements are going to be slight. That said, I've found:
NOISE
I've noticed a deeper exhaust note, but not overly so.
I can hear the turbo more than before.
POWER/TORQUE
I think there is a slight improvement in the top end; the revs climb more freely than before, and I feel the turbo spins up a bit quicker; perhaps a little more torque in there also.
FUEL CONSUMPTION
Slightly worse when WOT'ing it... this leads me to believe that it's producing slightly more power.
Slightly better when cruising.
Overall, don't expect miracles, improvements are slight.
Cold starts: Fine (-3*C yesterday)
Downsides: Can't think of any
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Completely agree with the above ^^
Mine made about 5bhp extra on the dyno :happy2:
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So you've never seen the engine management light? Also no with these winter-temps?
So no downsides for this mod?
Have you also noticed a better fuel consumption?
What's the most noticeable? -> The quicker/better gas response? The sound? The fuel consumption? The bhp?
Never experienced any warning light and all my friends also didn't. :wink:
On the orther hand I think pre cat removal is extremely overrated. I didn't feel any advantages.
Noticable engine response? No, don't get fooled by self-fulfilling believe. More power? Not what
you can ''feel' at all.
Yes, sound changes. It sounds more 'rough'. Personally it sounds louder, but less attractive, at
least with a stock pipe, not what I call a beautiful sound.
What's most noticable: When cold the car stinks. When I start in the morning and leave the car
to close my garage door it's stinking like an old car.
No question, on a new car I never would do this mod again. :fighting:
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So you've never seen the engine management light? Also no with these winter-temps?
So no downsides for this mod?
Have you also noticed a better fuel consumption?
What's the most noticeable? -> The quicker/better gas response? The sound? The fuel consumption? The bhp?
Never experienced any warning light and all my friends also didn't. :wink:
On the orther hand I think pre cat removal is extremely overrated. I didn't feel any advantages.
Noticable engine response? No, don't get fooled by self-fulfilling believe. More power? Not what
you can ''feel' at all.
Yes, sound changes. It sounds more 'rough'. Personally it sounds louder, but less attractive, at
least with a stock pipe, not what I call a beautiful sound.
What's most noticable: When cold the car stinks. When I start in the morning and leave the car
to close my garage door it's stinking like an old car.
No question, on a new car I never would do this mod again. :fighting:
Out of interest, is your car mapped?
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So you've never seen the engine management light? Also no with these winter-temps?
So no downsides for this mod?
Have you also noticed a better fuel consumption?
What's the most noticeable? -> The quicker/better gas response? The sound? The fuel consumption? The bhp?
Never experienced any warning light and all my friends also didn't. :wink:
On the orther hand I think pre cat removal is extremely overrated. I didn't feel any advantages.
Noticable engine response? No, don't get fooled by self-fulfilling believe. More power? Not what
you can ''feel' at all.
Yes, sound changes. It sounds more 'rough'. Personally it sounds louder, but less attractive, at
least with a stock pipe, not what I call a beautiful sound.
What's most noticable: When cold the car stinks. When I start in the morning and leave the car
to close my garage door it's stinking like an old car.
No question, on a new car I never would do this mod again. :fighting:
Wow? That's something totally different compared to other reviews?! Others are 100% positive. Dyno's give around 5bhp extra, etc etc...
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Out of interest, is your car mapped?
Good point. No, it's not. On a remapped ED30 pre cat removal may be a different thing.
On a K03 GTI I guess not. Keep in mind the Cupra R, Mk.VI Golf R, Audi S3 and TT-S also
have the same pre cat and they are reliable with ~ 270 BHP.
Wow? That's something totally different compared to other reviews?! Others are 100% positive. Dyno's give around 5bhp extra, etc etc...
Yes, I know. For many years now I read the positive reviews on the web and these made
me to remove the pre cat. To be honest I think it's neccessary to tell the whole story.
I don't doubt the 5 bhp increase on the dyno. But you won't feel this difference when
sitting in the car. So there are some very slight performance advantages. On the other
hand there are some downsides which I don't like: one hour of labour, a stinking car and
(to my ears) a less beautiful sound (slightly more drone).
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Turbo spool is noticeably improved, reduced EGT's are also a benefit. The pre-cat is seriously restrictive so I'm surprised you can't notice a difference. The gains are especially noticeable on a remapped car
You get a little more "spooling" noise from the turbo too. Fantastic mod that you can do at home. 5bhp is 5bhp, it's not going to be a huge kick in the back when you accelerate so im not sure if you were expecting more feel when you did it?
I got no drone whatsoever, no horrible smell (the cat takes the nasty smells out) - Milltek downpipes etc don't have a pre-cat and I've not heard anyone else mention a change in smell from them?
Its basically a great bang for buck mod :smiley:
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imho, I think the K03's are in need of a pre-cat delete more than a K04.
For the K03 to run anywhere near 270bhp, it's going to need stage2/2+ software and a full TBE which doesn't have the pre-cat, as the K04 doesn't need to run as high a boost level to produce the 270bhp it can cope easily with the pre-cat -- less boost, less heat, lower EGT's, less need for pre-cat removal.
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I don't doubt the 5 bhp increase on the dyno. But you won't feel this difference when
sitting in the car. So there are some very slight performance advantages. On the other
hand there are some downsides which I don't like: one hour of labour, a stinking car and
(to my ears) a less beautiful sound (slightly more drone).
I agree the 5hp isnt a huge amount and isnt going to create a massive improvement on the bum dyno, however with the precat in place at stage 1 levels of tune it can cause the EGTs to rise which leans the map will richen the AFR to cool it down hence lose power. I'll try and see if i can find my old logs which showed this. Kind of the same effect as heatsoak with the standard intercooler, except EGTs are alot more important to keep within limits.
If your going stage 2 then its probably a waste of time to do, however if your going to stay stage 1 at the most then i think its a great little mod that will aid longevity.
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I got no drone whatsoever, no horrible smell (the cat takes the nasty smells out) - Milltek downpipes etc don't have a pre-cat and I've not heard anyone else mention a change in smell from them?
Metallic cats do have much less mass than the stock ceramic one, that's why
metallic cats do heat up much quicker.
Nonetheless from what I know Milltek do also make a street legal DP with two
cats like many other makers do. This is the only way to run a Euro 4/5 car fully
street legal - at least what most exhaust makers claim.
BTW, the coming Mk.VII GTI will have only ONE cat, which is close to the turbo.
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BTW, the coming Mk.VII GTI will have only ONE cat, which is close to the turbo.
Thats exactly what it is like on the 1.4TSI. The cat is within a few inches of the turbo.
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Ok, so besides 'the bruce' I only read positive experiences with the precat removed.
In my situation I have a stage 1 (Abt) mk5 gti, with stock exhaust except the middle resonator (I replaced it with a Simons sport resonator and sound is excellent!) and I have no plans for stage 2.
Guess the removed precat will be a good and noticeable mod for me?!
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Guess the removed precat will be a good and noticeable mod for me?!
I would say so. I see no downside to it.
Less back pressure, lower exhaust gas temperatures, more longevity, free of charge, small power gain, quicker spool
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Ok, so besides 'the bruce' I only read positive experiences with the precat removed.
In my situation I have a stage 1 (Abt) mk5 gti, with stock exhaust except the middle resonator (I replaced it with a Simons sport resonator and sound is excellent!) and I have no plans for stage 2.
Guess the removed precat will be a good and noticeable mod for me?!
What's the deal with a Simons sport resonator?
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BTW, the coming Mk.VII GTI will have only ONE cat, which is close to the turbo.
Thats exactly what it is like on the 1.4TSI. The cat is within a few inches of the turbo.
Cost cutting measure then?
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BTW, the coming Mk.VII GTI will have only ONE cat, which is close to the turbo.
Thats exactly what it is like on the 1.4TSI. The cat is within a few inches of the turbo.
Right, the 1.4 TSI already had only one cat and this is also a metallic one with 400 or so cpi.
Ok, so besides 'the bruce' I only read positive experiences with the precat removed.
Ask a Volkswagen engineer and he'd probably say the same.
Guess the removed precat will be a good and noticeable mod for me?!
Nothing noticeable.
Cost cutting measure then?
Guess not. It's a metallic cat on the 1.4 TSI (I don't know any details of the coming GTI in this),
it's got an advanced noble metal coating and even more the tubing between turbo and cat is
double-walled for improved isolation and to retain the heat on the way to the cat - important
after a cold start and mking the pre cat obsolete.
I bet this even increases cost. :wink:
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What's the deal with a Simons sport resonator?
Some guys choose to remove the resonator (search youtube 'remove resonator golf 5 gti) for extra sound.
I didn't like the sound because I heard that you can get a vibration at cruising speeds and the sound is to loud with a cold start/stationair.
So I decided to replace the stock middle resonator with a sports model from the brand Simons.
The sound is amazing. Not to loud. No drone/vibration and a very nice sound when changing gears (dsg).
Pic:
(https://dl.dropbox.com/u/21854296/Sierstukken/foto.JPG)
Also replaced the two stock exhaust tips for two 80mm models:
(https://dl.dropbox.com/u/21854296/Sierstukken/IMG-20121125-00019.jpg)
I guess that together with the removal of the precat, this is the best price technically option with verrrrrrrry good results. (Total costs are around 260 euros over here in The Netherlands with labour included at a skilled mechanic/tuning company)
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Hi All,
I own a Skoda Octavia vRS Nov 2005 Model in India. Bought second hand, i was going all fine till the Floods played spoil sport.
Post flood, when i connected the VCDS, i did see 1 error code with respect to O2 sensor:
"16514/P0130/000304 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit
Possible Causes
Oxygen (Lambda) Sensor Heating Bank 1 Sensor 1 faulty
Possible Solutions
Check Oxygen (Lambda) Sensor Heating Bank 1 Sensor 1"
My mechanic suggested to remove the "Catalytic Converter" and check for blockage. And yes, the culprit was the Cat-Con. it was blacked out with carbon, disrupting the free flow of exhaust.
I was suggested to drive with Cat-Con removed and it turned out good as the car was breathing easily.
The Next Morning, i got to see the "EPC & Check Engine" lights glow. Given below are the error codes.
"17524/P1116/004374 - Oxygen (Lambda) Sensor Heating Bank 1 Sensor 1: Open Circuit
Possible Symptoms
Malfunction Indicator Light (MIL) ON
Possible Causes
Fuse(s) faulty
Wiring and/or Connector(s) from/to Oxygen (Lambda) Sensor (G39) / Oxygen (Lambda) Sensor Heating (Z19) faulty
Oxygen (Lambda) Sensor (G39) / Oxygen (Lambda) Sensor Heating (Z19) faulty
Possible Solutions
Check Fuse(s)
Check Wiring and/or Connector(s) from/to Oxygen (Lambda) Sensor (G39) / Oxygen (Lambda) Sensor Heating (Z19)
Check/Replace Oxygen (Lambda) Sensor (G39) / Oxygen (Lambda) Sensor Heating (Z19)"
and
"17511/P1103/004355 - Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low
Possible Solutions
Check Oxygen Sensor Heating for Oxygen Sensor before Catalytic Converter"
please help me understand if it is due to removal of Cat-Con? do i have to do some adaptive coding using VCDS to let the ECU know that i have removed the Cat-Con?
thanks in advance :smiley:
Guru