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MGF MoD
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Discussion Starter · #1 ·
Hi,

I know, some like to replace the catalyst by the well known bypass pipe.
I didn't cause I fear to get stopped in D at any time cause I'm on the road with the loud SP exhaust. Approved by the TUEV (MOT) but don't ask me how I got this approval ;)
If they get me, then 'they' investigate the whole car and I'd get huge troubles if the catalyst isn't there.

I looked around and found this nice part at the german Elise community.


--- cut from my affiliated webside--------
The catalyst from a german manufacturing site has 200 cells and is a metal catalyst. It can be used with engines up to 250 bhp. It passes the emission test (MOT).
Looks like the original and the measures a 100 percent compatible to the original until MGF VIN 522527 (MY 2001)

MOT. Will pass and the emission test is better than at the original.

Assembling: Remove the original (by use of some swear words due to the rusty bolts). Keep the both copper seals for later use.
Now you got two options with the bolts. Press out the old from the original and put them to the new, or RECOMMENDED:
Buy new M10 stainless steel nuts and bolts.

Power: Disclaimer, count in a slight power increase ;)

Sound: slightly louder than the original, but not so much as the cat bypass.
------------- cut end -------

Question is whether any similar part can be sourced from the UK and how much would it be.
 

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The Scarlet one returns...
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EXCLUSIVE! - Authored by Paul Sharpe (IIRC!)

As this is DEFINITELY a related subject, i have decided to copy the results of our catalyst test (including the sports cat). THIS IS AN EXCLUSIVE, AS IT HAS NEVER BEEN PUBLISHED ANYWHERE!!!!

OK, that said, the reason it was never published was that we got some strange emissions results on Andy Gilhooley's F which cast doubts on the other imperical data (although i strongly suspect it was only their emissions equipment that was playing up). However, the results are interesting never-the-less and it has been sitting on my hard drive for so long now it was about time it saw the light of day ;)

-----------------------------

TOP CAT


Since 1993, most new European registered cars have had to have a Catalytic Converter fitted. These devices fit in between the engine and the exhaust outlet, usually nearer the engine as they need to be very hot (about 400 deg Celsius), to work effectively. The Catalyst Converter (usually known as a ‘Cat’) consists of a honeycomb of precious metals, platinum and rhodium, which is why they are so expensive. As the exhaust gases pass through the honeycomb, they are converted from nasty gases, to nicer ones. Nitrogen Oxide becomes nice Nitrogen and Oxygen gases, Hydrocarbons become water and Carbon Dioxide while Carbon Monoxide becomes Carbon Dioxide. That’s the good news, the bad news is that the honeycomb in the Cat inevitably restricts the gas flow from the engine and slightly ‘strangles’ it which results in a slight loss of power.

A well looked after Cat coupled to a well maintained and well tuned engine, should last up to 100,000 miles. However there are many factors which will contribute to a much shorter life. Using leaded petrol (only a theoretical possibility these days) will coat the honeycomb, rendering it useless, while a back fire from a poorly tuned engine or when started up having run out of fuel will break the honeycomb – as will a physical knock such as going down a curb. Lots of short journeys will mean that the Cat will not reach its operating temperature and that will also see it reach a premature demise.

The MGF has been around for nearly 5 years now, and we’re starting to hear stories of cars requiring replacement Cats – as more MGF’s clock up the mileage and have annual MOT tests on their emissions, a new Cat could become a real possibility for many MGF owners. A quick look on the Internet shows that replacement Cats are big business, particularly in the USA where they have been around for a lot longer that we have had them in Europe. The good news is that as the market for replacement Cats becomes larger, more suppliers are entering the game, which is leading to an inevitable fall in prices. A few years ago it was not unusual to be quoted over £500 to replace a Cat, now £200 seems to be nearer the mark.

So, what are the options for an MGF owner faced with the news that their Cat has died? Well a group of five MGF owners got together at a rolling road to test four options:

Rover ‘Standard’ Cat
This is the cat fitted as standard to the car, available from any MG dealer at a cost of £??

Rover ‘Motorsport’ Cat
As fitted to the MGF Cup race cars, available only through Rover motorsport outlets at a cost of £. This unit should be fitted with a heat shield, which keeps heat in the unit, helping it to work at its operating temperature. Unfortunately the size of the heat shield is such that it will not fit onto an MGF fitted with a standard size exhaust silencer box.

‘Aftermarket’ Cat
In this case from a company called Fuel Parts, based in Bromsgrove, Worcestershire at a cost of £. This unit is an off the shelf unit and requires a flange to be welded onto either end to enable it to be fitted to the car. The unit has yet to obtain Type Approval for the MGF and therefore can only currently be fitted to pre ‘S Reg’ cars. However the company is currently considering obtaining Type Approval, after which it will be supplied with the mounted flanges already welded to it.

Catalyst ‘Bypass’ Pipe
This is basically a straight section of pipe with no catalytic honeycomb that fits in the position that the Cat would normally sit. Once fitted, it is illegal to use the car on UK roads and is really only for track use for those wanted to regain the few BHP lost by fitting the Cat.

The cars

It was decided to road test both a 1.8i (Scarlet Fever) and a VVC (Andy Gilhooleys). Significant to how the Cat would perform is its ability to deal with the volume of exhaust gases flowing through it and since the VVC produces more gas flow, it was deemed prudent to test both engine types. Both cars were fitted with the same aftermarket ‘sports exhaust’ to ensure that the exhaust didn’t restrict the flow through the Cat. Both cars had similar ‘sports’ air filters fitted, to enable the engine to breath easily and produce higher levels of exhaust gases, potentially at a level where the Cats may reach the limit of their operating specification.


The following parameters were measured on each car with each Cat:

1) Power and torque on the rolling road – Just how much power does a Cat rob, is it significant? Power was measured at 3,000rpm for both 1.8i and VVC cars, and at 6000 rpm for the 1.8i and 6,500rpm for the VVC, being the points where each respective car produces maximum power. Torque was measured at 2,500rpm and 5,500rpm for both cars. Each test was repeated three times to qualify the results.

2) Noise, measured one metre from the exhaust at idle, 4000 revs and 90% of peak revs (5750rpm for the 1.8i and 6750 for the VVC).

3) Exhaust gas emissions for Carbon Dioxide, Hydrocarbons and Lambda – are the Cats doing the job they should be and will they pass the all-important MOT test?

The results are shown in the tables below:

Table 1 – Rolling Road Results

Car/Catalyst Power (bhp) at 3000rpm Power (bhp) at peak rpm Torque (lb./ft) @ 2,500rpm Torque (lb./ft) @ 5,500rpm

1.8i/Rover Standard 72 124 129 118
1.8i/Rover Motorsport 73 126 128 120
1.8i/Aftermarket 74 125 129 120
1.8i/Bypass tube 73 127 128 120

VVC/Rover Standard 72 147 121 128
VVC/Rover Motorsport 72 148 122 130
VVC/Aftermarket 67 141 116 122
VVC/Bypass tube 67 144 117 126


Table 2 – Noise Tests

Car/Catalyst Noise (dB) at Idle Noise (dB) at 4000rpm Noise (dB) at 90% max revs

1.8i/Rover Standard 61.7 81.4 89.6
1.8i/Rover Motorsport 63.5 83.6 89.3
1.8i/Aftermarket 61.5 81.5 89.2
1.8i/Bypass tube 62.7 84.7 90.2

VVC/Rover Standard 67.0 86.5 92.5
VVC/Rover Motorsport 65.5 86.5 93.4
VVC/Aftermarket 65.4 86.2 92.4
VVC/Bypass tube 66.8 89.0 93.0


Table 3 – Rolling Road Results

Car/Catalyst Carbon Dioxide (%) Hydrocarbon(parts per million) Lambda
MOT Limits 0.30 200 1 +/-0.03

1.8i/Rover Standard 0.02 7 1.010
1.8i/Rover Motorsport 0 30 1.028
1.8i/Aftermarket 0 47 1.090
1.8i/Bypass tube 0.69 107 1.057

VVC/Rover Standard 0 0 1.058
VVC/Rover Motorsport 0.02 41 1.040
VVC/Aftermarket 0.42 43 1.093
VVC/Bypass tube 0.46 68 1.027


Conclusions

The Cat Bypass Tube
This failed the emissions test for both cars miserably. Although it produced a 3bhp gain over the standard catalyst, this would hardly be noticeable in day-to-day driving, and, surprisingly, it caused a power decrease on the VVC – possibly because the VVC needs a degree of backpressure, which would be lost by having not Catalytic honeycomb. It did produce more noise, particularly in the mid range, although it would be down to individual drivers to decide whether this was an advantage or not. So, its illegal for road use, produced a hardly noticeable power increase on a 1.8i and lost power on a VVC – not much to recommend there.

The Aftermarket Cat.
This performed well on the 1.8i car, passing the emissions tests, releasing 1bhp, hardly remarkable but at least it wasn’t a power loss. However it failed to make the mark on the VVC by failing to pass the emissions and robbing the engine of power. Examination of the unit produces a possible explanation for this failure; the unit has very sharp tapers to the inlet and outlet, which would produce extra turbulence within the unit – added to which the honeycomb is much smaller than either of the Rover units. On the VVC it would appear that the higher volume of gas flowing through the Cat is either too much for the honeycomb to cope with, or is too turbulent to provide adequate operation, or maybe both. The fact that the honeycomb is small, also questions the operating life of the unit, which would also may make this a doubtful purchase for the 1.8i owner. It does have a price saving of £, although it should be remembered that currently the unit has not Type Approval for later cars and comes without fixing flanges.

The Motorpsort Cat
As would be expected from a unit that has been developed to cope with the demands of Motorsport applications this unit worked very well, although the power increases were hardly impressive. The fact that the heatshield needs to be removed to enable it to fit on a road car is a concern although its absence did not effect the operation of the unit. However the heatshield would prevent heat seeping into areas of the car local to the Cat, so its absence may cause long-term problems. Added to that, the extra cost of £ over the standard unit hardly seems worthwhile.

The Standard Cat
This unit worked very well on the VVC car, along with the Motorsport unit being the only one to pass the emissions test. While the motorsport unit yielded a negligible 1bhp at peak revs over the Standard Cat, the Standard Cat does not have the concerns over the heatshield – it is £ cheaper. An obvious choice for VVC owners. On the 1.8i car the power is slightly down over the other options, but it doesn’t have any of the legislation or installation problems associated with the others, so has to be the recommendation for 1.8i owners as well.



Thanks to
Aldon Automotive in Brierley Hill for the use of the rolling road and ramp.
Fuel Parts in Bromsgrove for providing the aftermarket Cat.
Techspeed Motorsport in Leamington Spa for proving the Motorsport Cat and welding the mounting flanges onto the aftermarket Cat.
Andy Gilhooley for the use of his VVC MGF and Andy Phillips for the use of his 1.8I MGF.
Roger Parker who got his hands dirty doing the work to change the units over and Rob Bell, who along with Roger provided the technical insight.

-------------------------------

Well, there it is, for what it's worth. :D
 

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That's a great summary of the results, Andy. I have some pictures somewhere - really must stick them up at some point ...

Also thanks to (Officer) Roger Parker for not nicking me for my (then) illegal front tires!!
 

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MGF MoD
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57 Posts
Discussion Starter · #4 ·
Any idea whether the Techspeed catalyst was such a Metal Kernel thingy, mentioned above ?

The one I'm after is below 200 £ :D

Metal cat 200 cells


Original ceramic


Oh yes, I think the 'dark side' wins :)
At last it will increase the live of the original :rolleyes:
 

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The Scarlet one returns...
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Impressed! :D

OK Dieter, how did you do it? How did you get 2 pictures in the same post? :cool:

Only way i have managed this so far is to cut and paste additional pictures into one big one, but you have managed to put text between them and i am intrigued! :)
 

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MGF MoD
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Discussion Starter · #6 ·
Scarlet Fever said:
Impressed! :D

OK Dieter, how did you do it? How did you get 2 pictures in the same post? :cool:
Mate, I just keyed some buttons of the Forum features..
The 'IMG' button below the collection of smilies :)
Then paste the picture link to the appearing new window
:D
I see there under HELP some more options like PHP, whatever that may be.

Back to the header.



Someone in TW managed to get this crazy manifold from a company named 'Thunder'

Taiwan made engine breath option
 

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MGF and ZTT pilot :)
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Dieter, have a look at my web site for an image of the Techspeed supplied cat versus the standard item - full article (originally written by Paul, edited by me) http://www.mgf.ultimatemg.com/catalysts.htm



Image on left is the standard cat, the one on the right is the sports cat.

The sports cat is definitely the option I'd go for (for all the usual reasons Dieter! ;) )

Regarding the header, I love the look of that unit you've found - but the primary and secondaries are too short for big power improvements. The EBD system is, in this respect, the best option:



Unfortunately, this necessitates the deletion of the standard Flexi-pipe. However, I reckon I have a solution to this, using a pre-MY2000 pattern catalyst and a TF exhaust box, connected by a fabricated flexi-pipe. I reckon this would work nicely :)

I just need to save the pennies to develop the idea... usual story really :(
 

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The latter combined with this "spaghetti" 4-2 downpipe :)beerchug DK) gives a nice 4-2-1 system, that should perform well I think. I´ve heard a lot about spaghetti downpipes for other brands such as VW, and it seems they do very well,

David
 

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MGF MoD
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Discussion Starter · #10 ·
David,

that Australian manifold just looks like DIY works :angst :blah
Checked the link from the picture http://www.atc-int.co.jp but couldn't find anything about the nice looking flexi-pipe. Any more stuff known from your side ?

Though I'd be most interested on the TW made above.
Did you check the link ?
http://www.mgfcar.de/exhaust_specials/DL_DSC04162.jpg
Don's new downpipe is drawn there below the manifold.
Though the flange to that manifold is different from the standard.

Rob, the Elise downpipe missing the flexy part is well known, but also very expensive :confused:
Due to the Tech-speed sports cat compared with the one I found. The matter that the other looks nearly equal to the original part makes me love it (MOT and TUV, you know) and it's cheap with app 250EURO :D
 

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MGF and ZTT pilot :)
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Jeepers, about a month late returning to this thread - sorry! :rolleyes:

Interesting manifold there David. I wonder if any independent RR testing has been performed? The twin fexipipes are a neat touch!!! :)

The lack of a flexi with the EBD is anonying: Elise owners have now reported some breakages - and now are resorting to stiffer engine stay bushes . Frankly, I don't believe that this is a particularly comprehensive solution just meaning that instead of the manifold breaking at 20k miles, it does so at 60k :(

The EBD is expensive - so this means that the budget to find a flexipipe solution is somewhat curtailed :(

Anyway Dieter, glad you managed to find a TUV 'compliant' solution! ;)
 

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Dieter,

It´s the same guys that made the Super Sport-like front bumper.
More detail @

http://www.atc-int.co.jp/racingdesign/rdpricelist/C5AER-MUFimp.html

I received their full colour catalog at home, friendly chaps. Price is approx € 320,- which is ok IMO.

Dieter any idea about the BRM tweeter diameter (to fit in a home made mould)

Rob, I´ll request some info on RR info, if available.

cheers,
David.
 

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The Scarlet one returns...
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biervanhier said:
I received their full colour catalog at home, friendly chaps. Price is approx € 320,- which is ok IMO.
Interesting, early last year i sent them an Email asking about the front bumper. I was told that they don't export thier products outside Japan. But, if you have a catalogue then maybe they have changed thier policy.

I am going to Email them again about the bumper...:D
 

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MGF MoD
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Discussion Starter · #16 ·
Rob Bell said:
Anyway Dieter, glad you managed to find a TUV 'compliant' solution! ;)
*growl* Need to find a budged compliant sulution :rolleyes:

Noticed as well the Japanese downpipe upper flange looks different to the standard.
Full replacement required then including their manifold.
Dooh ! another lot of $$$$
 

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MGF MoD
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Discussion Starter · #17 ·
.. one month later. :beerchug

Got one of this special made 'Elise Community' metal catalysts from second hand. An Elise owner upgraded to the 100cells Motorsport Catalyst and sold the only 200km old one for 215 EUR :)

Metal catalyst 200 cells

Can't see any difference together with the current exhaust. Noise seams to have changed some dB A ;)

Everything still legal now, but the noise :angel
 
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