Supercharger/Turbo loads of information--NA (MK1) NB (MK2)

Forced Induction FAQ Version 2.6  This detailed information was gathered and edited by Smoke Mare  many thanks for the hard work in assembling the faq. GGW
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*** Don’t agree with anything said here? Let us know, we’re happy to retract or edit any of these sections with a view to presenting the wider opinions of the board. Feel free to correct us.***

# Which is better - Superchargers or Turbo Chargers?

This one is entirely subjective. Cars with a turbo and supercharger have different torque characteristics. Generally you tend to expect a more linear power delivery with a supercharger, turbo cars can suffer from what is known as ‘turbo lag’ in which you depress the accelerator hard, nothing happens then you get a sudden burst of power making the car difficult to control. This isn’t usually a problem though, the sensible turbo to fit on an MX5 intended for road use is a small one which will start to make meaningful boost at 2500 – 3000 rpm. For bigger power gains turbo tends to be the obvious choice, however supercharging an MX5 1.8 can easily give you greater than 180 BHP at the flywheel which tends to be more than enough for most peoples taste. Over 250 BHP has been achieved in extreme cases. Peak torque is said to be generally higher on the equivalent turbo setup, compared to supercharger setup.

# Which is more expensive - Superchargers or Turbo Chargers?

It is generally considered to be cheapest to fit a basic turbo package. As the target output figure can be higher for turbo, eventually the turbo will become more expensive if the target BHP output is high enough.

# Should I be worried about turbo lag and go for a supercharger?

Turbo lag is an issue, but the sort of turbo that tends to be fitted to an MX5 usually doesn’t have too much of a problem. The usual thing to fit on an MX5 is making 12 psi or about maximum boost for a standard installation at 3000 rpm. If you think about Honda VTEC or Toyota VVTi engines, they change to the more aggressive, cam setup at 6000 rpm. During normal spirited driving your revs aren’t really going to drop below 3000 rpm unless you are doing something silly. The time turbo lag will catch you out is trying to accelerate from a stand still around a wet round about, if you forget about it at this point you are likely to have to wrestle to avoid a collision. Once you know about it you should be able to drive accordingly. A supercharger with a large intercooler will suffer from what feels like a very similar effect unless you remedy it with a dual throttle or fit a smaller intercooler and water injection to reduce the throttle body size. If you are still not sure, ask for a passenger ride in a turbo and decide whether the lag is something you can handle then.

# How does Forced Induction make cars more powerful?

Air and fuel burn best at a particular set ratio, too much fuel and your mixture is rich, degrading performance and worsening fuel economy. Too little fuel and your mixture is lean, increasing the risk of pinking, knock and engine damage. What this means is forcing more fuel into the cylinder would have no effect except make your engine run richer. Forced induction forces air into the cylinder, allowing you to force more fuel in, more fuel burned = more energy released = more power. When people talk about ‘boost’ in psi, this is the pressure at which air is being forced in, generall more boost = more power, but with more risk to the engine.
Thanks to Captain Muppet for suggestion on how to improve this point.

# How do Superchargers work ?

In the most basic terms possible you have a compressor, with an inlet and outlet plumbed into the air intake on the engine so it forces a greater amount of air than atmospheric pressure into the engine. It is powered by an accessory belt, much like if you had a car air conditioner fitted, only instead of compressing gas to cool the cabin, it compresses air to force more into the engine.

# Whats the difference between Coldside and Hotside Supercharger kits?

Hotside means installed over the exhaust side of the engine, coldside means over the air inlet side. Basically, the Coldside kit is pretty much redundant now. It was developed to avoid poor throttle response given when you intercooled a hot side charger to get more power. Now a dual throttle kit is available which solves the problem but still allows you to fit a large intercooler.
Thanks to Captain Muppet for suggestion on how to improve this point.

# How do Turbo Chargers work?

The principle is identical, the difference is what makes the compressor spin. Rather than being driven by a belt from the crankshaft, the compressor is driven by a turbine mounted in the exhaust system, so the more exhaust gases the engine pushes out, the faster it spins the compressor.

# What sort of gains can I expect from a supercharger installation?

A relatively high spec Performance 5 installation was discussed on the forum, Thread with specification and link to dyno image Basically an intercooled MP62 with a sophisticated ECU fitted to a Mk2.5 1.8i made 266 BHP peak wheel HP.

# I can’t afford a FI installation, won’t fitting a sports exhaust and cold air/free flowing air intake give me big gains?

In theory yes, there should be gains in HP. Cold air is denser and therefore gives you more power, an engine breathing more easily should release more HP. In practise however the gains are very limited. In independant trials, where people done before and after dyno runs, the difference is subtle. These mods only offer a large gain if the engine intake and exhaust is restrictive and is reducing the HP capacity of the engine. With the MX5, Mazda designed in a fairly efficient system, so what you get out of the box isn’t far from what you can get. What an air intake system might do is alter the torque curve slightly and change the revs where you get maximum BHP subtly. Also it’ll sound nice and rorty!

# How good are these ‘electric’ super/turbo chargers that are on Ebay for around £100 or less?

These items will do nothing at all. If any effect is felt it is probably down to placebo. They cannot physically force enough air in to make any difference, if anything they will restrict air and reduce power, plus there is the risk of cheap, flimsy plastic parts breaking up, being sucked into he engine and breaking your car.

# Okay but how about {insert cheap car accessory seen on Ebay} ?

The general rule is that if something costs less than £200, but claims to give you more power and improve fuel economy, and is universal so fits any car - it’s going to be a waste of money. I may be proven wrong on this, if there are exceptions I will happily list them.

# So what is the cheapest way of getting a few more horses?

Early Mk1 cars have a modification called ‘the 14 degree timing mod’ whereby the factory timing setup isn’t perfect for maximum power. The general consensus is that this offers less than 5 HP, but is cheap to do. If you want to go faster but can’t afford FI, the next thing you can do cheaply is increase your power to weight by removing weight. Take your spare wheel out of the boot, and the carpets, tools and whatever other rubbish you have in there. Strip as much of the interior trim out as you can live without. The MX5 is fairly light anyway so to get any real benefit you are going to have to work hard and sacrifice quite a bit, even then the gain would be minimal. All in all you are fighting a hard battle trying to improve the performance of an MX5 in a meaningful way without spending at least £1000.

# How much BHP can I gain by using higher octane fuel?

If your car has an active knock sensor - then in theory a tiny bit. In reality any gains you feel are probably more down to placebo - or the effect of the drastic weight reduction in your wallet. Some owners like to run a tank of Shell V-Power through once in a while for the additives which are supposed to be good for the engine, whether this is worth while is a matter of opinion. If you have fitted FI then you should probably run your car on high octane as a matter of course, tuning to higher octane gives a little more headroom and less ‘knock’ sensitivity.

# I’m doing a trackday, how can I get a cheap temporary boost in performance?

The best thing to spend your money on is driver training. That will stay with you, anything you bolt to your car is going to be worth next to nothing when you come to sell it. You can leave your spare wheel at home, take a can of ‘get me home’ and your RAC card and hope you don’t have a blow out. Or as Captain Muppet suggested simply leave your spare in the pitlane. Other than that, it’s a matter of adding nitro methanol to the petrol, which can add a few temporary HP at the risk of adding too much and damaging the engine.

# I’m fitting a Turbo, what else do I need to fit to get the most out of it?

Everyone’s opinion on this will differ. The two things that get screwed up when you start forcing air into an engine are timing and fuel mixture. If an engine runs too lean it will get damaged, if the mixture is wrong enough this will happen very quickly. For this reason, fitting a knock sensor comes highly recommended. As for actually manipulating the air to fuel ratio, the cheap option is an AFPR or Active Fuel Pressure Regulator, or a device called a Powercard and alter the base timing. These are not particularly sophisticated though and effectively supply more fuel on demand without altering the timing to suit the revs. This means that through the rev range there will be points where timing and mixture is not at it’s optimum for maximum power and safety. A better choice would be to fit a piggy-back or replacement ECU or computer that can alter both the mixture and the timing. Popular choices are the Emanage Blue and Emanage Ultimate for piggy-back, or Mega Squirt for the budget replacement ECU, alternatively an Emerald or Adaptronic would do the job. An intercooler will improve power, but make having a more sophisticated form of timing and fuel management more sensible. If you are increasing the power of the car by more than 40 HP an uprated clutch is strongly recommended. As you will then be going so much faster suspension and brakes are a good choice to improve. The general consensus is also that turbo cars require an uprated clutch at a lower BHP increase than supercharger cars.

# I’m fitting a Supercharger, what else do I need to fit to get the most out of it?

See above – most of what applies to a turbo apples here too, water injection seems popular for superchargers.

# Should I fit a turbo exhaust if I’m fitting a Supercharger?

No, a turbo exhaust has no baffles as the turbo acts to dampen noise, if you fit one to a supercharger it will make your car sound like the exhaust has fallen off. Fit an N/A exhaust.

# Should I fit a N/A exhaust if I’m fitting a turbo?

Theres no harm in it, however the baffles in the exhaust that are not needed when you have a turbo are slightly restrictive. Turbo’s don’t need back pressure in the same way as non-turbo engines. The net result is a turbo will work fine with an N/A exhaust but you might be losing a few BHP and a little throttle response by not fitting the appropriate exhaust.

# How competant a DIY mechanic does it take to fit Forced Induction?

It should be do-able by most people who are used to maintaining cars. Wiring in and tuning the piggy-back ECU or replacement ECU can be a daunting task and it’s worth doing some research before you start it. The plumbing on a supercharger tends to be considered slightly easier to put together than that of a turbo.

# I’m fitting a supercharger, but because the throttle is now in the wrong place the throttle cable is too short! I need a longer throttle cable!

Easily solved, there is a genuine Mazda part available, I believe it is listed as being for a Mazda B2600 utility. According to Daz of MX5NUTZ Mazda Part number: FB44-41-66OC can be modified to fit the Jackson Racing charger and will suffice, if albeit tight for an MP62. See here for detailed instructions.

# I’ve seen a charger unit for another (Non-MX5) car on Ebay, will it be relatively easy to fit to my MX5?

The most commonly asked about charger is the Eaton M45 off a Mini Cooper S. They are a common sight on Ebay due to cars being broken and people upgrading to the John Cooper Works version. Everything said here is relevant to the conversion. Practical Performance Car covered it once, but it is a completely bespoke installation, a far cry from an MX5 JRSC M45 kit!

Probably not, it will be possible, but the plumbing is all going to be in the wrong place. If you are able to fabricate your own parts and are willing to experiment and generally faff around a lot it might be do-able. This route is not for the inexperienced owner who wants a fit and forget solution.

# What sort of problems am I going to come across trying to fit the charger unit for another (Non-MX5) car?

The brackets are going to be wrong, this applies even if you are trying to fit a unit for a 1.8 MX5 to a 1.6 car, the holes will be in the wrong places, there might not be room for it under the bonnet, the plumbing will have to be thrown away and fabricated from scratch… In a nut shell this is possible, but it’s more of an engineer’s job than a mechanics. If you have to ask about it, you probably don’t have the ability to do it.

# What sort of BHP increase am I going to be able to get before I have to fit an uprated clutch?

People seem to think 40 BHP is about the going rate. It is going to depend on how you drive though. If you have a habit of burying your foot on the accelerator and flicking your other foot off the clutch, leaving trailing lines of smoking rubber on the tarmac you will break it quicker. If you drive very carefully and smoothly you might be able to put more BHP in before it’s required. Some people fit the FI, see if the clutch slips while they are driving and decide whether to do the clutch accordingly. The general consensus is also that turbo cars require an uprated clutch at a lower BHP increase than supercharger cars because of the higher torque characteristic of turbos.

# At what sort of BHP increase am I going to have to start thinking about a full engine rebuild?

Difficult question, to a degree it’s a matter of opinion as to what is safe and cost effective with reference to the model in question. As an example Phil at P5 quoted 275 BHP as being a level of power that you would need to think about rebuild for an MP62 installation on a Mk2 1.8i. He also suggested 245 BHP as being the level at which you might have to think about rebuild for the Mk2 1.6i. According to cbr6fs and 200bhp this might be less so. Torque is the thing that damages engines and as peak torque is higher in turbo installations the BHP figure that is safe is likely to be lower. It’s sensible to investigate whether you need it at 240 BHP, but at 240 BHP you probably have as much as you would sensibly want for fast road and track in an MX5 anyway. Unless you were planning extreme additional modifications. Obviously this figure is probably less so for 1.6i cars.

# Whats the point in fitting bigger injectors?

As you go higher in the power game you start to need to get more fuel in as well as air. Bigger injectors allow this. However not all ECU are able to cope with all injector sizes.

# Whats the difference between the various ECU packages?

The Emanage are popular they have two models, the cheaper Blue which can only handle smaller injector sizes and has no auto-tune function out of the box, then theres the Ultimate, which has an auto-tune function ready to go if you have fitted a knock sensor and wide band O2 sensor. This will means they will tune the engine as you drive, to the parameters you set. You can either set a dangerously lean air to fuel ratio for maximum power, a conservative and safe but uneconomical rich mixture and anything in between. At the very least you can get running without a rolling road session. A professional tuner who knows what they are doing might be able create a far superior map for you, but auto-tune is still useful to get you to the tuning centre. Of course some ‘pro tuners’ are actually not going to be good enough at their job to get a better result than the auto tune, ask for references. Mega Squirt is a replacement rather than piggy-back and is available as a build it your self or a plug n’ play package. It’s a low cost option for lots of flexibility but probably more suited to people who are more familiar with ECU’s and tuning and maps and what not. There are others, but Emanage and Mega Squirt appear to be the most popular. Emerald, Hydra and Adaptronic are popular too, but less suited to the home tuner. Not all ECU are suitable for all size injectors, all target BHP figures. If you are tuning the Mk2.5 with it’s VVTi then you are probably looking at the more expensive, less home-tuneable ECU.

Following the demise of Greddy Japan, availability of Emanage might come into question. Following some limited research I’m now of the opinion that Adaptronic is a very good choice for the home tuner and probably a very good choice full stop! I will elaborate once I’ve managed to absorb more information on the topic.

# I want to self-tune, but I’m a bit of a novice, so it sounds like the Emanage Blue, the Emanage Ultimate or the Adaptronic are for me - what’s the difference?

Some of the advantages of the Ultimate are:-

  • Ultimate has a USB port Blue only has Serial.
  • Ultimate can handle bigger injector sizes.
  • Ultimate can store more maps.
  • Ultimate can autotune.

* From what I gather, the Adaptronic is all about autotuning, and it doesn't have the limitation of working against the factory ECU. In theory if you set up the idle and the no load map correctly, and set the rest of initial setup well - you should be able to make all sorts of mods and the ECU will automatically sort out the maps to make the most of them (Actually I proved to be incorrect about this last point, if you fit a supercharger afterwards, you will have to re-tune the on-boost part of the map.)

# Alright but whats the difference in tuning procedure between Blue and Ultimate, seeing as the Ultimate has auto tune?

Okay, for both ECU you wire the ECU up, wire in all your sensors, wideband o2, knock sensor, variable throttle position sensor. Now the next step in both cases is to get a base map running that is as close your cars installation as possible. Worst case scenario you can choose the Mazda Engine stock as an option. Now if you have a Blue, you drive the car carefully, see how it feels, see what sort of figures it throws back at you after a drive - then alter the fueling and timing settings to what you think will be better, then go for another drve and so on. During this time you will want to be red lining it in different gears, depending on the startup map and the sort of tune you are looking for this might take a while, if you start getting knock you need to stop and look at your basic setup.

If however you have an Ultimate it's slightly easier, simply set the auto tune function to on. Set the readings you want to be getting out of the various sensors then drive around and let it alter it's fueling and timing pattern itself. Afterwards disable the auto tune and you can tweak the settings up or down to fine tune, all in all it should be quicker and easier.

* Availability of Greddy Emanage may come into question, so the usefulness of this information is now slightly limited.

# I don't fancy a piggy-back, the Adaptronic sounds interesting - what can you tell me about it?

I asked about the Adaptronic some time ago, see this thread

Phil from Performance 5 provided these answers:-

smokemare wrote:
1. In the video i can see where RPM is charted against timing, and I see kPA but I don't know what kPA is - I can only assume it's load upon the engine which will change in different gears and if you are going up or down hill? Is this correct?

Edit: From Martin Young
"Kilopascals" It's the air pressure in the inlet manifold, so it's directly equivalent to engine load as you surmised.

As Martin states, kPA is the pressure in the manifold. 100kPA is atmospheric pressure, anything low than 100 is vacuum and anything over is boost. Unlike the standard airflow meter, kPA doesn't truly represent the density of the air unless an air temperature sensor is used whereby the ECU can make the correct calculation.

smokemare wrote:
2. In the video is someone sitting in the passenger seat tuning or is the ECU doing that by itself and just outputting the graph to laptop?

Edit: From Martin Young
The laptop's doing it by itself. I ought to leave the other questions to those who've actually fitted an Adaptronic.

There's a couple of tools with the Auto-Tune function. There's Rapid Learning for quickly getting the map points within an acceptable range and then the fine tuning Slow Converge. These are done 'Open Loop' so you're changing the raw map.

smokemare wrote:
3. Once you're idle and no load tune is sorted - in theory you don't need to plug your laptop in again?

Once you're tuned, then a laptop isn't required. The Adaptronic works best with a Wideband o2 Controller for Closed Loop operation. Installation of say a LC-1 is very neat, as the controller plugs straight into a serial port on the ECU.

smokemare wrote:
4. If you fit an adaptronic you lose the factory immobiliser if I understand correctly - what is the best solution to this security issue?

There's an easy work around for this so you don't lose the immobiliser.

smokemare wrote:
5. if you've tuned idle and no load, and have been driving it issue free for a few weeks - then you bolt a supercharger/turbo on - will it re-map automatically without you even plugging the laptop in? I was under the impression it would!

Would be nice, but no. The 'off boost' part of the map should need no further work, but you'll need to tune the boosted parts. The graphical image of the fuel table makes it easy to define the map before you start tuning to make the job quicker and safer!

smokemare wrote:
6. Is it safe to install it under the bonnet or does it need to be installed in the cabin like an EMB or EMU?

It needs to go inside the cabin as like most ECUs it's not designed for the harsh under bonnet environment.

smokemare wrote:
7. What additional sensors do you need to fit and wire in for it to be able to autotune safely?

You'll need a MAP sensor, air temperature sensor and Wideband o2 sensor/controller. The ECU can use the stock knock sensor on M2 models. I always use an independent knock sensor connected to earphones.

smokemare wrote:
8. How difficult is it to install? How long should it take a reasonably competant person to A: Fit, B: Initial tune?

It depends on your knowledge and confidence level. You'll have a base map to start with, so really you'll only be tuning fuel. Depending on whether you source your own sensors, you may have to configure them first.

It's worth reading the thread as more was discussed, it gives a good general idea of what's involved. If you're interested the software can be downloaded and played with without an ECU from the Adaptronic site.

# The Adaptronic sounds great! How much are they and where can I get one?

Phil at Performance 5 should be able to provide one, the kit with all the sensors you need should come to less £1000, expensive - but it is a sophisticated ECU and probably worth it if you can afford it to get the best out of your installation. Not to discourage from the other options, such as the Emerald or others, they are great too - but the Adaptronic sounds like a good choice for home tuners.

# What about MPG? Am I going to send my fuel bill through the roof?

The principle of tuning and modding cars says yes, to transfer fuel energy into kinetic energy you burn it. The faster you burn it, the more kinetic energy you get. Its not quite as simple as that though, a turbo car will burn fuel faster when it's 'on boost' or you are high in the rev range compressing air into the engine. When you are cruising at 1500 rpm in 5th gear, you probably won't use any more fuel than stock. Similarly modern superchargers have a shut off valve, so when you are idling or cruising it sort of disengages and your economy is back to normal. Also, with an aftermarket ECU you are going to try to manipulate the fuel to air ratio. It may seem odd, but the more lean the mixture - or the more air there is to fuel, the more power you are going to get, the risk is that if you go too lean you start to get detonation or 'knock' whereby the explosion happens slightly at the wrong time and damages the engine. If you run rich you will burn fuel more quickly and get less power for your trouble. What this amounts to is that how much MPG you get comes down to how the car is tuned. If it's tuned well, then when you are pottering around you will get as good as near stock MPG, but when you bury your foot - you're MPG is going to go down. Some FI users report improved MPG during conservative driving, but lets face it, the grin factor is going to see you nudging that throttle more than usual for at least a few weeks, so expect to burn some fuel.

# Okay I'm sold, I'm going FI but how much power should I aim for?

If you've decided to go down the darkside route, then you should think first of what is your budget, then what you want to achieve. If your budget is £1200 or less, then you are probably looking at adding the most basic turbo package and gaining something like 40 HP. The price break, where expensive starts to merge into ridiculous seems to be at somewhere between 230 BHP and 275 BHP for the 1.8i versions. At above that level you are talking about replacing most of the engine to cope with the pressure, plus it will become increasingly difficult to get any power down onto the tarmac without being ever so soft with your accelerator. Expect to pay £4000+ if your goal is >230 BHP at the very least. Possibly less if you are planning on DIY'ing out of salvaged or second hand parts - good luck! Probably more if you are planning on dropping it off with an order list of what you want done at either MX5MAD or P5. Obviously it all depends on options and current prices - I'm just trying to give a very rough idea. For £2000 - £2500 you should be able to get within spitting distance of 200 BHP if you are starting with a healthy Mk2 1.8i 140 BHP.

# Right I'm fitting FI - do I need to fit a Air to Fuel Ratio Gauge and a boost guage?

Basically no, you don't NEED to fit them. If you are tuning the car your self you should get an Air to Fuel Gauge but it can fitted to tune and removed once you're happy with your maps. The advantage of fitting these is they give you information to tune your car. As you in theory don't tune it every time you jump behind the wheel, you shouldn't need to perma-fix them. The disadvantage in having these is they are an advertisement for theives, that your car is a bloody good fun joyride. The shiny intercooler behind the grill, the 12" bonnet scoop, the whale tail spoiler and the exhaust so large you have to check there are no cats resting in it before you start the engine might give it away, but if your car looks like stock why make it thief attractive with something you don't need? The only strong arguement for fitting them, is if you are running a silly high spec and need to constantly monitor these things to avoid detonation. Another disadvantage is, the common place to install these is in the central air vents, blocking them up with gauges will make the heating/cooling system less effective. Pods are available that bolt on the dash, but they give a particular look and aren't to everyone's taste.

# I'm fitting FI and I'm going DIY all the way, whats the best order to do things in?

It's often suggested that you should fit your piggy-back or replacement ECU and all the extra required sensors first and get it running properly N/A. It sounds ridiculous but it really is a seperate job in it's own right and it's these things that will keep your engine safe after the main job of fitting the blower. If I was going to do an FI installation myself, my choice would be to fit a Greddy Emanage Ultimate, knock sensor and wide band O2 sensor. Wire all those in and try to get the engine running normally. The Ultimate has a relatively easy to use Auto tune function provided you have the right sensors and there's probably at least a few hours work there in itself - particularly if you haven't done it before. Then I would drive the car for a few weeks to make sure all the wiring was good and iron out any teething troubles. Then once I was 100% sure the installation was problem free and all the sensors were working properly, I would think about fitting the turbo or supercharger and re-tune. You would get no performance benefit until you fitted the blower, other than making the job of getting the blower working properly and tuned easier and less likely to be troublesome. This might not apply if you are going for a low boost, powercard or active fuel pressure sensor installation with a change in the base timing. For the pucker job though, that's easier for the less knowledgeable amongst us it seems a sensible way to go about it.

*NB: If you have an older car you might need to fit a new throttle position sensor too - the originals had a basic on/off switch so couldn't really be used for tuning.

# All this talk about Mk1, Mk2 and Mk2.5 - Can't I get my Mk3 blown?

In a word yes, probably, but it's going to be very expensive, time consuming and problematic. Aftermarket parts have been developed for the earlier cars already and are now mass produced and sold reasonably cheaply. As of July 2008 I know of no completed, off the shelf FI kits for Mk3 cars, so anything you do will be 100% bespoke. The problem is the market for Mk3 mods is smaller, people who buy the current model tend not to like to invalidate their warranty by messing with them. By the time the Mk4 arrives there will probably be some stuff available, so either buy an earlier mark or be patient. According to Berkeley352 there are several kits 'in development', we could be seeing offerings from Flyin Miata, Bell and Cosworth USA soon. Cosworth USA have already released pictures of their kit:-

Cosworth MX5 MP62 Kit

# I want to make my MX5 roughly match the performance level of {Insert popular performance car name here} - What to I need to do to achieve it?

The probable answer is that you can't. Things like, weight, balance, tyre width, gearing ratio, aerodyanamics will mean that whatever you do you may not be able to match something else perfectly. You can alter the gear ratio, you can change the weight distribution, you can pull the arches out and fit wider wheels - but it's never going to be exact. It begs the question - why not simply the sell the 5 and buy X car instead? The level of modification required is probably going to render the conversion 'none cost effective' and it might not feel much like an MX5 anyway by the time you've finished.

# Should I go to Karl at MX5MAD or Phil at Performance 5?

Either or both. Both Performance 5 and MX5MAD have a plethora of happy customers, both who have bought parts or have dropped their cars off for engineering. They do have their differences, MX5MAD have preferences for some things, Performance 5 for other things. If in doubt speak to both. Of course they WILL have the odd unhappy customer - they're only human, but most people are very happy with BOTH companies.

# P5 and MX5MAD are miles away! Isn't there another option!?

Yes, if you search your local directories for engine tuning, you should be able to find someone competant. You can then import the stuff you want fitting yourself, or buy mail order from P5 or MX5MAD. The advantage is that you/your chosen installer is going to be able to get technical support more easily from P5 and MX5MAD, and if things go seriously wrong - you could always take your car to them to have a look or ask if (for a fee of course.) they could travel to your car and see if they could sort it out. These things aren't going to be an option if your supplier is based in Canada. Unless you are fitting it yourself, or live overseas I would suggest taking it anyway. Get an overnight stay near their premesis and a train ticket back if it's a long way - at least you know when you pick your car up it will be sorted. Besides, yes if you live in Scotland it's going to be expensive and a pain - but think of it this way, set your Sat Nav to avoid motorways and you are going to have a lot of fun on the way back from picking it up!

* Another option is wgtautodevelopments based in Cheshire. Members have had work done there with positive results. Give them a ring, or email them, ask for Pip Gardner.

# Can't I get my MX5 up to 270 BHP N/A? If so how?

In a word, yes you can. The trouble is it is a very costly route to follow. You are talking about either rebuilding the engine extremenly hardcore uprating everything. Or putting a different engine in altogether... The engine that Mazda put in has pretty much everything it can put out being put out as stock. Cold air induction, timing mods, different manifolds or exhausts - there might be a BHP here or there, but for real noticeable gains, going FI or spending £10,000+ on N/A mods are the only options.

# Is it really not worth going N/A? I like the feel of N/A cars!

In a word no, if you like the feel of N/A a supercharger will be closer to an N/A than a turbo, slightly. The only real reason you would spend £10,000 modding an MX5 N/A up is if you were competing and adding FI would put you in a category you weren't comfortable racing in.

# Why can't I just fit a super chip?

Simply put, Mazda wrangled as much BHP out of their little engines as they could with the cost restraints upon them. Without changing parts, reprogramming will do nothing as it's all ready programmed to get as much as it can out, as it comes from the factory. The only exception to this is that by advancing the timing on some early Mk1 cars you can free up a couple of BHP and push the torque band higher into the rev range.

# How about an engine transplant? Can I fit {insert particular engine here}?

In theory you could fit a more powerful engine to get more BHP N/A. The problems lie in getting something that fits into the MX5 and makes sense. There are some popular Ford Mustang and Rover V8 conversions, that make silly power and there is a Lexus V8 popular in Australia or so I'm told. But then you do that you are making the car heavier, harder to handle worse weight distribution and your MPG is going to go down to silly levels of economy. Sure you can have a monster fast 5, but it's not to everyones taste as it makes certain compromises. You could fit a V6, the problem is there isn't a standard kit to do it and this is going to make the project time consuming and difficult. I hear you can fit a Toyota Supra 3.0 V6 Twin Turbo, but you have to cut away most of the bulkhead, remove the heater and site the gearstick further back. You can fit anything in theory, but there will come a compromise somewhere along the line that will mean the conversion is not to everyones taste. Part of the problem is the shape of the MX5 engine bay, it won't take tall engines without heavy modification which rules out many of the sensible choices for a V6. Also you have to think about wieght distribution, an MX5 is particularly well balanced, if you fit something non-standard you might end up with too much weight on the front wheels, worsening the handling. You can get 300 BHP out of the Mazda 1.8 if you spend enough, so why pay more for the same power output? Anything can be done, but there will come a compromise somewhere!

Captain Muppet corrected me on this section, I'm not particularly knowledgeable about engine transplanting - except it's hard. His full correction relates mainly to the Supra engine, which is an inline 6 rather than a V. For everyones benefit, his insights follow:-

The Supra engine is an in-line 6 not a V. Inline engines are longer than Vs for the same number of cylinders (nearly twice as long) so fitting an I6 means you run out of space at the front and back of the engine bay. V engines tend to be lower than in-line (not taller as you suggest) but they are wider and need space for an exhaust on both sides - which means you run out of room at the sides of the engine bay. Swapping other in-line 4 cylinder engines is the easiest in tems of pacakging room, but even then the sump will need modification to clear the subframe, as well as modifications to the chassis or gearbox to mate to the MX5s Powerplant Frame. Mazdas own 13B rotary engine can also be fitted, but again, not without custom fabrication work.

The MX5s 1.6 and 1.8 engines have a heavy cast iron block, so larger aluminium blocked engines could be fitted without a weight penaulty (the Nissan SR20DET or Honda's S2000 engine might work well).
It might be worth ending this with "If you didn't know all of this already it is unlikely that you are ready to engineer an alternative engine installation."

* If you're thinking about an RX8 Renesis conversion, the consensus is, Yes it's possible, but it's a relatively problematic conversion and probably not worth the hassle and cost. Spend the money on something else, or a FI conversion, UNLESS you are desperate to enjoy the 'feel' of rotary in your 5 and cost/hassle is not an obstacle.

# I want to do an MX5 FI project, what's the best car to buy as a donor?

The general consensus is a 1.8i of some description. Beyond that it comes somewhat down to taste. The Mk2 1.8i 140 BHP model is best for high power, a higher starting point is good, but not having the VVTi of the 147 BHP Mk2.5 is a good thing for FI, makes it simpler and allows a little more headroom. The advantage in starting with a Mk1 1.8i is that it's a slightly sharper more focused car, maybe a better choice for a person doing track work.

In addition to this, the 1.8i is a better choice because it has:-

* Bigger brakes
* Bigger clutch
* Stronger differential
Of course these issues can be resolved - but obviously at increased cost!
*Thanks to Captain Muppet for suggestion on how to improve this point.

# What about {Insert model of MX5/Eunos here} version? What can I fit to that?

Basically anything can be fitted to anything, but in some circumstances there is no standard kit to do it. This is going to mean more problems and more expense. If you have a Mk1 1.6i there are some nice and cheap turbo kits available, and if you look harder you can find supercharger kits, at the time of writing a Jackson Racing M45 kit is available off the shelf and there is talk of a more powerful MP62 kit coming soon. The Mk1, Mk2 and Mk2.5 1.8i have lots of stuff available for them, Turbo kits, M45, MP62 kits, you name it. The poorer candidates for FI are the later low power Mk1 1.6i, mainly due to a lower starting point and the Mk2 1.6i, mainly because most of the kit was developed in America, where they only have the 1.8i version of the Mk2/Mk2.5. The Mk2 1.8i has a small advantage over the Mk2.5 1.8i VVTi because the VVTi requires more sophisticated tuning to get the best out of it and possibly less head room due to the different compression.

# Wouldn't it be easier to just buy a car that's already been done?

In a nutshell, yes! The trouble is apart from the rare BBR turbo or the rarer still Mazdaspeed turbo imports, all turbo and supercharged MX5's are bespoke projects and there will be a lot of unknowns in buying one. Who did the work? Did they do the work properly? Has it been messed with since? Is the engine about to blow up? If you take someone who knows there stuff with you and you can spot a good one it will save you thousands of course. The trouble is, modifying you car is something of an act of personalization, many people go FI because they love their car but want more go. Of course if you don't have a 5, but want a quick one, then buying a modified one will save you a lot of time and hassle. Of course be careful and try to take someone who knows what they are looking at. There's a lot more that needs to be looked at on a modded 5 - you wouldn't want to pay extra for a £50 cheap, plastic, electric turbo whizzer off Ebay would you?

# I'm not sure about buying one of these bespoke 'pimped' cars isn't there a standard factory turbo version?

Yes, several. However the turbo editions are very limited. Option 1 is a BBR Turbo, offered in 1990 it had a 1.6i engine with a Brodie Britain Racing turbo fitted. The factory option developed 152 BHP but Brodie could up this at the cost of losing your warranty. Less than 1000 of these were sold. Option 2 is a Le Mans special edition offered in 1991, it was basically a BBR turbo with orange and green racing livery, copied from the Mazda 787B Le Mans winning car. Due to the extreme paint job proving a hard sell, it's rumoured a few of the 24 cars built were sent back for a more standard looking paint job. As only 24 were sold, they are something of a rarity and expensive collectors item now. Some owners got sick of the racing colours and resprayed them a more standard colour. Option 3 is a 211 BHP 2002 MX5 SP, developed and sold in Australia, only 100 cars were sold, they were rather more expensive than standard, shipping one here would be expensive. Option 4 is the 2004 Japanese Special Mazdaspeed version. It developed 178 BHP and production carried through into 2005. The problem is they are incredibly rare on these shores, with less than 6000 made, it might be that more start to find there way over in the future, but being so different to the UK car and requiring SVA because of the cars year might keep them a rare sight on UK roads. Of course there is the American Mazdaspeed version, but then you're in left hand drive territory - something of a compromise.

# What about a standard factory supercharged version?

There has never been one, and probably never will. The closest you will get is a Mk1 Japanese import that has been fitted with the Mazdaspeed aftermarket supercharger kit.

# Why aren't there more technical articles here about how to do stuff like there is on MX5NUTZ?

Mainly because there are lots of good technical articles on MX5NUTZ, why duplicate them?

# I want to learn more about turbo and supercharger science - where is a good place to start?

There are two books by the engineer Corky Bell, who is considered knowledgable about both systems that are often suggested reading material.

  • Maximum Boost: Designing, Testing & Installing Turbocharger Systems (Engineering and Performance) by Corky Bell

  • Supercharged: Design,Testing and Installation of Supercharger Systems (Engineering and Performance) by Corky Bell