Ok a few ppl have been asking the same questions so I thought its about time i did a proper post.
The Eco-Tec Valve
Well to be honest It does make a difference but without the silencer is very noisy. It does aid fuel economy and increase low end pickup BUT and its a BIG BUT you loose loads of torque after about 4000 rpm and dont seem to go anywhere. Personally i really wouldnt bother.
Decatting Your Motor
Well all I can say about this is do it. Im not sure what difference it would make if you had a standard exhaust but i have a full system and putting the cat back on for MOT was depressing. At the moment we can't legitimatly put are cars through the mot test without one even if its an early J. However, there is one way to get your car through an mot without a cat even if its not an early one. Simply write a reciept saying that you purchased an engine from a scrap yard and the year of the engine is 1991. The mot tester can then only give your car a pre-cat test and it will pass.
Exhaust Manifolds
Known as
Headers in the states. These are a greate mod but ive yet to find anywhere in the Uk who does them. I got mine imported from the states. They are 2.5" My only advice to anyone who gets some is be prepared to mod them as mine didnt fit very well at all. One over thing. Make sure your current exhaust fits perfectly as these usually dont have a flexi joint which can make fitting even more interesting. Definatly an increase in power and torque though.
FSE Power Booste Valve
Well to be honest I was a little disapointed at first with this but having decatted my car you can feel the difference. With the decat the car will happily pull off the clock but with the fse boost valve connected it seems to want to be there all the time. Just one thing it does use more fuel, but the car has more torque top end and just wants to keep pulling.
FSE dont list the Valve as fitting the MX-6 but the Probe one fits. Part No. VK-384-TOY1-H and is £98 + VAT
Fuel Rail Mod
Quite a few ppl on the other forums have done this. It does make a difference and lets face it its a FREE mod (dont get many of these) so you might aswell. Ive found you do feel a difference but its really only at the top of the rpm (especially in 5th).
Follow this link for the how to guide:
http://www.rs-productions.com/RSP_Mo.../banjobolt.htm
Throttle Body By-Pass
Ive done this now and found it does make a difference. This mod simply by-passes the throttle body of coolant. This is meant to be for those silly cold mornings inorder to help warm the engine up a little. In reality its rarely that cold in this country and even when it is our engines run fine without it. The bonus to not running coolant through the throttle body is the intake air is cooler and denser. Again this is a FREE MOD!!! just simply follow the pipe from the back head to the throttle body and recoonect it to the egr valve or if you have a j-spec to the thermostat.
Induction Kits
The two main options in the UK are Pipercross and K&N. Both do kits but again list them for the probe not the MX-6. They do make a difference top end and make an impressive induction note. However, because our engines get hot id suggest trying to get a CAI from america or make your own. I have a Green Universal Filter (cause i get good discounts and they are ace).
Phenolic Intake Manifol Thermal Insulators
Ok having been to nearly every probe and MX-6 forum ive heard someone say something about Intake Manifold Spacers. While a good idea I wasnt convinced it would make a huge difference. However, my fuel economy has gone up slightly but I can now see the need for a CAI or Custom CAI. Ive tested it with the standard air box and it seems to improve performance and marginally with the induction kit. Im hoping it will make more of a difference when I do my CAI at the end of the year. You can notice a difference and the Intake manifold is noticably cooler which is always a good thing. They werent to difficult to install but leave yourself the day incase you start to have problems. An interesting mod and well worth doing if you have to remove your inlet manifold as you dont need gaskets!!!
http://home.san.rr.com/scmorgan/spacers/
Stage 1 Clutch
Well I was forced into changing mine after the spiget baring callapsed. The reason I went for an uprated clutch is because are stock clutch was designed for the 2.0l and isnt really upto it especially if you want to make serious performance mods. The stage 1 Clutch isnt what I would class as a race clutch but is noticeably different. I nolonger get clutch slip at all when trying to drag off the lights and the feel is slightly heavier. If you have to replace your clutch beaware it might be worth taking the uprated option.
MX-3 Flywheel
If your either changing your gear box or changing your clutch you might want to consider this mod. Its probably the easiest way of fitting a lighter flywheel to our cars. Its very easy to change while either changing your gearbox or clutch. It makes a slight difference to performance and seems to pull better through the gears and be far happier to rev.
Speed Limiter - J-Spec's Only
If you have a J-Spec unlike the UK Cars your speed is restricted by the ecu to 117mph. There are lots of stories about if you change the clocks to uk ones then the limiter wont work but this isn't true (trust me). The Easiest way round this is to locate the ecu (its under the stereo) and to cut the green wire with the red stripe. However, this does cause an over fueling problem when you let off. Other than this you could fit a Uk Spec ecu and vaf (but you would loose power and you may experiance problems as it looks for the egr valve) or even have the ecu remapped however, ive found a rather cheaper option to this. If you remove the throttle pedal fit a push to make microswitch (you will need to make a bracket and fit it) so that it makes the connection only when the throttle isnt depressed. Now link this through the green wire with a red strip and ever time the throttle is depressed it removes the limiter but when you back off it wont over fuel. It wont cause a fault code either unlike just cutting the wire.
J-Spec stuff
ECU and Vaf
The easiest thing to fit off the J-Spec engine to a UK car is the Vaf unit (or one off an mx3 v6) and the ecu. This is like giving yourself a chipped ecu. It is possible to fit either ecu (manual or auto) to a manual uk car but if you are fitting it to an auto you need one from an auto. These are rather rare. They have different VRIS opening stages and the rev limiter is set higher. It also doesnt have any control for the egr valve so this will stay closed. But thats a good thing as you loose power when its working anyway.
J-Spec Inlet manifold (Heads and Cams)
You can fit the J-Spec inlet manifold to the uk engine but be prepared to have to port the head a bit to get the inlet ports to match. If at all possible get a set of j-spec heads and cams. The j-spec heads have better ports and flow and also have larger inlet lifters and valve springs. The J-Spec cams are also different. The exhaust cams are exactly the same but the inlet are higher lift and have a longer duration helping your motor breathe.
J-Spec Engine Block
If your lucky enough to find an intact J-Spec block in good condition and you have no intention of fitting nos or forced induction snap it up as these have flat top high compression pistons.
UK compression ratio 9.2:1
J-Spec 10:1
Suspension and Handling
StrutBraces
Ok it might not be the most obvious mod but if you drive your six quick and spend a lot of time attacking bends you might want to concider fitting a front strutbrace even if you have standard suspension. I fitted mine before i fitted Mazda Speed Adj. and found that it didnt wonder at high speeds (i mean silly quick) and round the bends it was more positive. The rear strut brace wasn't as noticeable but still made a small difference.
Only one problem. They dont fit J-Specs without modification nor do they fit if you fit intake manifold spacers.
I will try and keep this updated as I add more.
Last updated 26/05/04