Am I right in assuming the new theromstat that comes with the CAI, fits on the top of the new thermostat extension and not in its original position which would now be at the bottom of the thermostat extension?

IIRC, you are not right. The thermostat should be at the bottom. This might be the cause of your leak. (1/00)

Our '5' has now covered well over 20,000 miles since fitting the Jackson Racing C.A.I. kit (83,000 in total). I reckoned the foam panel air filter could benefit from a clean.

After (unsuccessfully) searching for a UK supplier to provide me with a Jackson Racing foam air filter cleaning kit (part number 901-970). I finally purchased some excellent products from a motor cycle specialist. What you need is a powerful cleaner that won't dissolve plastic or glue, and a very tacky oil but which can also penetrate the foam layers.

PJ1 Foam Filter Cleaner Spray (part 15-22)
PJ1 Foam Filter Treatment Spray (part 5-20)

Instructions are easy to follow and cost should be around 5 per aerosol tin plus any P&P. I got mine from White Bros.. (Darlington) Ltd. Tel. 01325 483121 It was amazing to see just how much dirt washed away. All in all, super products and plenty left over for several more cleans and treatments.

Just be careful folks that you use the correct products for your type of filter. Cotton and foam filters use very different fluids. (2/00)

The best peice of advice I can give anyone is to get a 1/4" socket drive, an extension for it, a 10mm socket and a universal joint. You can then disconnect the aluminium air box adaptor from the airbox. This means no force/fiddling required to get the air box in place and you can also attach the air flow meter to the adaptor out of the car and lower it into place - brackets and all. No hassles with fitting the bracket to either the adaptor or the air flow meter and no messing about with the thermostat, either in terms of moving it or having to take it out and put it back in. With these tools (cost me about 10 quid), the job just becomes so much easier - I could probably fit one in under an hour... Careful reading of the instructions and having a decent socket set with extensions etc and a decent set of spanners (and a big adjustable spanner if you have power steering to bend a bracket) means that the job's not too difficult at all. I'm a computer games programmer - I know next to nothing about car engines, and I did it - so that means it can't be too hard at all....!

Remember the universal joint though - it's impossible to separate the two parts without it. Of course, you don't need to - it just makes it bloody awkward otherwise - not difficult - just fiddly... (2/00)

I agree with the above- it's a piece of pizz as long as you follow the instructions that come with the kit. I only had one problem and made one deviation from the instructions.

The problem: I couldn't understand how to refit the bonnet prop, which must now lie at a different anglw within the engine compartment. In the end, I fitted a hydraulic prop (cost about $40).

And the deviation from instructions ? Same as above: disassemble the black plastic box from the aluminium elbow, fit to the car separately. I used a combination of 3/8 drive sockets, knuckle and extender to do this as the bolts & nuts are fiddly. The instructions go to great pain to describe 'forcing' the pre-assembled kit into the car, telling you to go ahead and push/bend/scrape - oh, and ignore any cracking sounds ! But, much simpler to disassemble first.

Note that the newer kits don't mention or provide a replacement thermostat, so there's no need to do anything there. I soldered the wiring connections - all in all, an easy install and plenty of smiles afterwards :) (2/00)

The JR CAI is for normally-aspirated engines only. I can highly recommend it, but just note that if you spend $350 on it, you'll have to remove it before you fit your charger.

The forced-induction setups will have some sort of integrated/dedicated air intake system anyway, some of which include an intake over the mouth (just like the JR CAI) while others will include an intercooler of some sort.

You can see my JR CAI at http://www.crosswinds.net/dublin/~franksm/mx5/4.jpg and http://www.crosswinds.net/dublin/~franksm/mx5/8.jpg

BTW the air fliter used by the JR CAI is a free-flowing filter similar to the K&N and other filter. It's a small, flat panel filter. (3/00)

There's 2 things I know of:-

- relocation the catch that the bonnet prop uses to a hole near the drivers side headlamp so that the prop is almost up against the coolant bottle. You can then remove the bonnet prop, bend it a bit and get it to go over the CAI. I then used to tie a cloth round the prop and it used to rest snugly over the CAI. Of course this all changed when the Mazda dealer did the accident repair and just plain cut a hole in the CAI so it now goes through!!! Works OK actually but I can't help but feel the mechanics have a banana-heavy diet if you know what I mean.

- get a hydraulic bonnet prop from Performance Buyers Club or similar. Drilling required if you have a Roadster as the hole in the bulkhead isn't big enough. UK cars OK I believe. Check before you buy. (3/00)

I've done a lot of homework and searching reviews etc. and I've come to the decision to buy the Racing Beat intake also marketed with a different bracket (cruise control would you believe) and instructions by Crazy Red Italian.

They all seem pre-occupied with the way it sounds, I'd be more interested in any gains at the back wheels... I know the intake is $155 (what's that in £'s?), I have a couple of questions..
1. Has anyone in the group had experience with these products/companies?
2. Where, if anywhere, can you buy them from in the UK? (I gather the service from Crazy Red Italian is very good but the product is too much at $169) (4/00)

I bought the RB unit from Crazy Red a couple of years ago and put 20,000 happy miles on it before upgrading to a JR CAI. From Crazy Red, it cost $200 incl. shipping. It was very easy to fit, and worked a treat - power increased a little and fuel economy became better also. But it was worth it mainly for the way it freed up the engine (slightly), allowing it to rev better. Plus the noise that it makes... hmmm...

I can recommend the product, and I can also recommend the people at CR - very good and friendly to deal with (I asked them loads of questions over email prior to and after buying) (4/00)

Fitted this weekend with much problems (but then its not MX5 specific) performance easily outways the difficulties.

Basically a cone filter in a heat shield with a venturi effect cone bolts onto the air flow meter. (Like the brainstorm mega heat shield cone thingy).

I had to fabricate a small bracket to hold the airflow meter and cut some bolts down in length and get a square to round adapter. A silicone hose fits onto the front of this and directs cold air direct onto the filter. Mine sits just behind the gap in the bonnet where the headlight is.

Loads of torque and because the unit is sealed trottle response is almost always instant as there is already cold air in the heat shield. Cost 135.

Looks good and like stock not bodged (which is surprising for me). Sounds not much different but can hear the tube sucking. Much improved drivability when combined with 14 degree timing.

Only regret that I couldn't either get RAM pipe into the gap behind the mouth of the 5 or drill the bumper and fit there with adaptor supplied. Maybe later tried last night but too much engine in there to route a big tube. Might have to see what I can do about getting more air in somehow eg. headlight cover etc. (7/00)

Be careful going to low with that hose. A couple of weeks ago during a thunderstorm I was driving to Mansfield, Notts where roads were quickly turning into rivers. Outside Kingsmill Hospital I came across a rather large lake on the carriageway which nearly turned the car into a bathtub!

Having had water shoot over my head (top down) during an underestimated ford crossing previously, I was aware that the profile of the car tends to scoop water. On this occasion I was very relieved that I had not taken a hose to the mouth. The engine would have drowned and I would have had to swim! (7/00)

Went skiing last week, arrived back in Dublin on Sat morning after getting an hour sleep the night before (big session on the last night in Austria!). Waiting for me was a nice big package containing a Jackson Racing Cold Air Induction Kit. Fitted it that afternoon (still no sleep but wide awake now!) took about 2 hours as one of the bolts would not fit properly into the front cowl (I have ABS so the windscreen washer bottle filler cap was in the way by about 5mm after moving it about a little), this was easily fixed though later on with a big black cable tie ;-)

Went out for a spin... first impressions... Wow! The noise, the vibration, the kickin the back when u drop from 3rd to second at 4000rpm, the acceleration in 5th up to 70+, the kick in the back when accelerating in first and u get to about 3500/4000 rpm, I'm really really impressed, I didn't expect this much of a gain!!!

I took a friend of mine for a spin (I didn't tell him about it), I did the 3rd to 2nd shift to overtake another car.... I quote him "HOLY SH*T!!!" , heh heh I assume the gain is helped by the rs-r header I installed a few weeks ago, the cat pipe and cat back exhaust to get better breathing from the engine.... (?) Its a really nice piece of kit and fits well. Anyone who can hold a wrench can fit one of these, nothing complicated.

One question I have though.... after fitting, when the car is warm and the engine drops to idle, the revs "bounce" a little, is this due to an air leak somewhere (haven't had time since Sat to retighten all screws/bolts) or is it just a matter of upping the base idle from 850 to ... something higher? (3/01)

I'm looking to give my '99 MK2 SE a small power boost budget is c £200, choices are:
1) Monster Air
2) Brainstorm Powerstack
3) Racing Beat INtake with K&N Filtercharger
4) replace the stock air filter with the K&N version (and save myself a few quid!)

What are people's views/experiences on these, please? Number 3 seems to have got the better reviews on Miata.net, looks most professional and seems best positioned for cold(er) air in the engine bay. Downside is it needs sourcing in the US, but I can't see that being a problem. I know these products give little (if any) power gain..it's (as I understand it) mainly a case of slightly freer revving and much throatier engine noise. I used to run a Supercharged MK1 (fantastic!), but don't wish to spend the money on either parts or insurance this time round. All comments welcome. (6/01)

I went option 3) although the full Toucan product from R-active with the intake ram pipe too. Cost 120 + brackets etc. as it was a universal kit. I think all told I managed around 125 but I'd reckon on more like 150 if you had to buy all the bits retail.

I'm very happy with the result but if I was doing it again. I'd think about going ITG foam panel filter and running a pipe from the standard air box through the firewall to the air intake near the windscreen. Would cost around 35-45 depending on where you buy your tubing and hole maker from.

Max Power etc. always recomend drilling the bottom of the air box when replacing the filter. I personally can't see any benefit in doing this as you may get more air in but potentially risk losing airflow so not too sure about that mod. I prefer the sound of Foam over Cotton and have always had better on road results from Foam (Esp. ITG stuff). (6/01)

I have a '99 Mk2 and an R-Speed Monster Air intake (bought from Moss, www.mossint.co.uk) I can't compare it to any of the other options, but I'm *very* happy with it, especially in tunnels :-)

For a full run-down, installation description, pictures, and sound samples (sad, I know!! I'm fitting an FM dual exhaust this weekend to see if that helps with my massive psychological problems!! :-) see: http://www.geocities.com/MotorCity/Speedway/2034/rspeed.html (6/01)

Header" is the US term for exhaust manifold - i.e. the front part of the exhaust pipe from the engine back to the catalytic converter (which is about half-way to the back).

For reviews and more information on exhausts, take a look at http://www.miata.net/products/intex/

I get the impression that you would only get about 15bhp (at least on a Mark2) by replacing the air intake AND exhaust manifold AND the rear exhaust section (aka silencer, back-box, cat-back systems) - i.e. maybe free up about 5hp each for these 3 "pieces". But that's just my general impression from reading around - I know very little about the specifics on free-flow manifolds. (6/01)

I remember reading someplace that Manifold replacement is one of the worst value (in terms of cost vs power increase) modifications you can make. I've have had 2 Roadsters that came with very expensive looking 4 branch manifolds (one was 4-1, the present one is 4-2-1), and quite honestly I think the difference between these cars and other standard manifold MX5s/Roadster 1.6's I've tried is pretty marginal under normal driving conditions (you might notice more of a difference on the track though). A cheap change that really impressed me after driving a 1990 1.6 Roadster before and after was a cat replacement pipe. In theory, the standard cat is pretty free flowing (well, so I read), and that taking it off shouldn't make all that much of a difference. The 120k km cat taken off looked in good shape. The cat pipe used was a Scorpion stainless steel pipe (the brand of pipe used I don't think makes a huge difference). The car seemed to have a lot more low end pick-up, which I suppose is where it matters on the road. It was running on the stock exhaust, but with a K&N filtercharger intake. Maybe the old cat has blocked somewhat, so explaining the performance increase. But I've had testamonial from the owner of a very late 1997/8 Mk1 1.8 (last Mk1) who took off his cat (these cars have a very restrictive looking long catalyst thats very easy to remove) and replaced it with 2" copper pipe, with a flange braized at one end (late cats only have one flange). Again, he reckons it has really free'd the engine up. I have a Scorpion pipe currently in the boot, waiting to go....;)

Scole Engineering came up with a neat solution regarding manifold modifcation. They reckon the stock manifold is already a pretty good design, compared to other production manifolds. They have produced a modified down pipe that effectively turns the manifold into a 4-2-1 design. Pretty impressive numbers I seem to recall from Gaydon when combined with their shortened intake (at the time it looked prety messy, but hopefully they've tidied it up a bit by now). I think it was being touted at about £150-200 all in. (6/01)

after all at £500 you're getting close to a HKS turbo kit

£500 for a Hks turbo? Where from? At mx5parts there £2000. Even a greddy is 1100 pounds? Id be surprised if you got more than 4hp out of a header, and even then you really need to do the zorst, cat and airfilter. (6/01)

I might be wrong here but isn't any gain made by the header only realised if you have a free flow exhaust?

As I understood it yes. You start at the back and work forward other wise you have a lovely large bore pipe all the way through to a peashooter outlet and don't achieve much. (6/01)