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yes i tried running just the air pump plumbed into the exhaust on the FD , it didn\'t bring the emmisions down much at all.
 
0.18% is a fail on the CAT test for MOT. the FC are all non-cat test, so all good.

i was fed up last year when my fd rex failed MOT on emmisions, after 7 years the MOT station reckoned it was on the VOSA database and had to pass the cat test....plus they reckoned the exhaust was too loud....new rules dontcha know.
 
the car had 2000 ppm CO with a 3 inch straight through system and petit ECU, basically twice the limit for a cat test.
 
To try a fix i bought the shortest, cheapest catalytic converter i could find on ebay. 3 inch diameter pipe and low cell density i.e. not much catalyst, see here http://www.ebay.co.uk/itm/410300-FLOWMONSTER-Catalytic-Cat-Converter-3-/140375059193?pt=Motors_Car_Truck_Parts_Accessories&hash=item20af016af9
The catalyst bit is at least 4 inch dia, and it doesn\'t look restrictive, you can see through the cells, prob about a mm square each.
 
anyhow, cut a long story short, it wasn\'t much bother to chop a section out of the midpipe, splice in the ebay cat and weld in a small tube before the cat to plumb in the air pump.
 
Result....40 ppm CO ( 0.004%) on MOT test and  50 ppm HC....a resounding pass...its a green machine for the cost of a £60 cat.
I don\'t have power figures so can\'t confirm any power loss, but this is about as high flowing as a cat can be and the effect on the emmisions was huge.

my fd3s is throwing oil out of the upper dump valve when changing gear, its covering the air filters in the engine bay.
 
is this likely to be the turbo oil seals ?
any tips on where to get them rebuilt in hertforshire/ St albans area...or even someone good to fit them ! Don\'t fancy another weekend trying to fix it.
 
only upside i can see.....it could be a good excuse for a single turbo

[The catalyst test is part of the MOT test for most class IV spark ignition petrol engined passenger cars with four or more wheels first used on and after 1 August 1992.]

i\'ve got my dates slightly wromg...memory going with age.
 
its pre 93/92 for non cat test.
 
from mot MANUAL\'
 
The catalyst test is part of the MOT test for most class IV spark ignition petrol engined passenger cars with four or more wheels first used on and after 1 August 1992.

the bit that is new relating to imports;
 
The vehicle will be tested according to its age from first use-The only exemption to this is if the vehicle owner can present to the tester at time of test a letter from the vehicle manufacturer stating that the particular engine as originally installed could not meet the equivalent British emission standards. If this is the case, then test to the next lower emission standard.
e.g. A 1995 car first used in Africa has a letter from the engine manufacturer stating that the particular engine (engine number to be stated) cannot meet Catalyst emission limits, then use the pre cat limits of CO 3.5%, HC )200ppm

Is it an import? If so check on the V5 for exactly when the car was registered. It may have a 94 plate but is it registered with the DVLA as post July 31st 1995. This is the cut off date for imports not having to go through the fast idle test. If this is not the case, you need to contact them and ask them to apply their rules properly.
 
Depending which department of the DVLA I speak to my car is registered in 1992, 1995 or 1997 which does create problems at MOT time.

 
yep; checked this on v5 mine is 94. Pre 94 is definetly a non cat test, post 94 is the more stringent test.
 
its difficult for me to see how MOT stations can bend the rules now its all computerised, but there are obviously lots of uncatted 94+ RX7s around.
I will contact Mazda, maybe a letter with emmisons specs for 94 jap RX7import will keep the tester happy ?
I will also ring VOSA and double check about jap imports .
 
Do you guys think even with a cat fitted it would pass ? i guess the only other way is a mappable ECU to lean out for emmsions testing........a great excuse to tell the missus when i blow £500 on a power FC !!:D
 
 
the exhaust noise is more subjective, your average TVR or porsche turbo is pretty loud, this is a similar type of vehicle for comparison. But if your running a single box, 4 inch system i think your chances are slim ! i have a super dragger back box and let in another intermediate box, small oval silencer (£50), the difference was noticeable and it really cut out the loud spits/bangs at idle, but still a nice throaty warble.

Is it an import? If so check on the V5 for exactly when the car was registered. It may have a 94 plate but is it registered with the DVLA as post July 31st 1995. This is the cut off date for imports not having to go through the fast idle test. If this is not the case, you need to contact them and ask them to apply their rules properly.
 
Depending which department of the DVLA I speak to my car is registered in 1992, 1995 or 1997 which does create problems at MOT time.

 
yep; checked this on v5 mine is 94. Pre 94 is definetly a non cat test, post 94 is the more stringent test.
 
its difficult for me to see how MOT stations can bend the rules now its all computerised, but there are obviously lots of uncatted 94+ RX7s around.
I will contact Mazda, maybe a letter with emmisons specs for 94  jap RX7import will keep the tester happy ?
I will also ring VOSA and double check about jap imports .
 
Do you guys think even with a cat fitted it would pass ? i guess the only other way is a mappable ECU to lean out for emmsions testing........a great excuse to tell the missus when i blow £500 on a power FC !!:D
 
 
the exhaust noise is more subjective, your average TVR or porsche turbo is pretty loud, this is a similar type of vehicle for comparison. But if your running a single box, 4 inch system i think your chances are slim !  i have a super dragger back box and let in another intermediate box, small oval silencer (£50), the difference was noticeable and it really cut out the loud spits/bangs at idle, but still a nice throaty warble.

My first post so be nice !
 
i have searched on this topic and i have had my 94 RX7 for 7 years now without problems at MOT time. Its had the non cat test for emmisions, however this year (same garage) it was given a cat test and failed ( of course !)....no cat, large bore exhaust.
 
the tester gave two reasons why it was different from last year
1. it now comes up on their electronic system as cat test
2. the MOT manual now states that an import has to have letter from the manufacturer saying its not designed to pass UK emmisons. This statement is new.
 
How do you guys get round this ? Anybody got a letter !!!
i\'m in welwyn garden city in herts, so if you pass on the name of any friendly RX7 MOT testers that would be great.
 
p.s they also failed it because it was too loud...again new wording in the testers manual. To be honest it was a bit noisey so have added an extra box to keep the MOT and neighbours happy ! But owning a modified jap import seems to be getting more hassle than its worth