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Last month I detailed our throttle body setup for our Renault Megane F7R engine based around Suzuki GSXR 750, this month i wanted to detail the engine management system that’s going to be the brains behind the outfit.

Whilst there are many aftermarket ECU’s available to buy, none is quite the same as Megasquirt for getting your hands dirty. Megasquirt originally arrives as a bare circuit board imported from America, along with a bag of components all which need to be soldered into the correct positions of the circuit board.

Whilst this is a fun process, once you’ve built up a few of them it quickly gets repetitive. Luckily for us, being an electronics company, we have access to a wave solder machine, so we just push the components into the board and send it through the machine and a wave of solder rises up and goes underneath the board and solders the components leads all at once. We offer both assembled and in-kit-form Megasquirts in our online shop.

Megasquirts can run pretty much any configuration, from 2 cylinders to V12s and is highly configurable, in fact it can be an overwhelming experience the first time you open Megatune (the software you use on  your laptop to configure and “tune” your Megasquirt).

Its advisable, if possible, to find someone else’s configuration just so you have a starting point. Unfortunately for us, Megasquirts used on Renault engines don’t seem to be a popular configuration (yet!) – for our other project car (a Focus ST170) we managed to locate and download a configuration within a ten minutes of Googling – for the Megane we hit a brick wall.

A couple of years back we setup a Megasquirt running a Renault Clio F7P engine on similar throttle bodies, this was used to take the car the engine was mounted in (a Volvo!) around Croft race track. Our plan is to use the F7P configuration and alter it to suit the Megane engine – one of the major differences is the flywheel configuration.

The F7P uses a 32-2-2 Flywheel (see illustrations) whereas the Megane uses a 60-2 configuration – the majority of cars utilise a toothed flywheel so the engine management knows the exact position of the engine. As each tooth passes a flywheel sensor (“variable reluctance sensor” to quote its official name) a small voltage is generated – the engine management waits for the gap and then starts counting teeth – in the case of our Megane flywheel case we have 60 teeth and 2 missing teeth – hence 60-2.

The F7P flywheel is a bit of an old ball because it has two joined up teeth and two missing teeth – I ended up modifying the Motorola microcontroller assembly code for the Megasquirt to properly support the 32-2-2 flywheel as its an odd configuration to get it working properly but the Megane one is a pretty standard configuration so it should just work out of the box.

Once you know how many teeth and how many are missing the next thing to work out is the tooth number that will be under the flywheel sensor at top dead centre – tooth number one is the tooth immediately after the missing tooth so its pretty easy to work it out, especially if you’ve got the gearbox and engine block separated so you can visualise it all!

The next thing thats different in our configuration is the fuel injector impedance – a fuel injector contains a coil which is energised for a very small fraction of time (a few milliseconds) to allow a certain amount of fuel to flow through every two engine cycles – this coil has a resistance (impedance) – high impedance injectors can be controlled directly from the Megasquirt as they don’t require as much current to open – low impedance injectors either need power resistors inline with them or controlled with a pulse-width modulated (PWM) signal – both of which the Megasquirt supports. Again by googling the part number of your fuel injectors its easy to find out the resistance of your injectors – failing that by using a simple multimeter on resistance check between the two terminals on each injector you can measure it yourself – typically high impedance injectors are around 15 ohms whereas low impedance are around 3 ohms.

If your interested in receiving a copy of our F7P or F7R Megasquirt configurations please feel to get in touch and I’ll e-mail the relevant data files across, next month I’ll detail the more interesting setup of the Megasquirt – ignition and fuelling tables and our fuelling strategy (AlphaN vs Speed Density).

TrackLogic Piranha – a dashboard mount touch sensitive screen which features

• Two line 16 character display
• Full OBDII fault code database onboard so if a fault does arise your not just presented with a fault code but a full description
• Real time sensor information
• Speed camera alerts (when connected to our GPS module)
• Engine alerts – if any sensor goes out of tolerance the unit notifies you
• Rev counter
• 8 LEDs which can be mapped to display engine RPM or lambda
• MicroSD card slot featured on the left hand side of the unit – all data captured is recorded to MicroSD card for later viewing in our TrackLogic DataViewer software
• Fully compatible with all our TrackLogic range of sensors/wideband controllers
• Built in accelerometer for measurement of g-force and calculation of BHP (in-car dynometer).
• Currently supports all OBDII compliant vehicles OR can be connected directly to a Megasquirt with appropriate adapter cable
• Ford enhanced version (enhanced-PIDs) due mid-November – displays and logs not only OBDII standard parameters but things like VCT error, VCT angle etc..
• Available to purchase November 2011 via our PistonFreaks.co.uk website

Check us out in this months Performance French Car magazine where we start to detail our Megasquirt setup for the Megane F7R monster we are creating!

We are now stocking assembled and unassembled versions of the Megasquirt V3 PCB in our online EFI store (PistonFreaks.co.uk).

The MegaSquirt EFI System is truly the dream Electronic Fuel Injection computer for the DIYer. MegaSquirt has been installed on thousands of engines from restored classics to daily drivers to full on race-cars. Turbo, supercharged, or NA the MegaSquirt can handle your fueling needs. More information about MegaSquirt can be found at www.megamanual.com.

This is the unassembled kit version of the Megasquirt – all components are labelled and supplied all you need to provide is the solder and labour for assembly! We also stock a pre-built version of the kit, see our other Megasquirt items.

All of our Megasquirt kits also come with a cd containing the latest Megasquirt tuning software and our tried and tested Megasquirt to USB cable for connection up to your laptop – all free of charge.

Free shipping also applies to this product

Features / Benefits of the MegaSquirt-I EFI System

Just a quick note  really to mention that we’ve added a 2003 Ford Focus ST170 to our fleet, this one was bought for a very good price as it has a few small issues that we intend to solve.

First one is engine management light comes on, after reading the fault codes Lambda Sensor #2 (which is just behind the cat.) is reporting heater short circuit and we’ve got a missfire engine code which is something to do with the VCT setup.

Last month I detailed how to setup vernier cam pulleys after we fitted a pair of fast road cams and adjustable pulleys to our Megane F7R engine. This month I’m going to detail our custom built individual throttle body setup (ITBs).

We started out purchasing a set of used Suzuki GXSR 750 motorbike throttle bodies, these are a good set of throttle bodies to start with as each one can be individually separated – the Megane F7R ports are spaced differently to the 750 so the first job was to manufacturer aluminium spacers to go between each throttle body, these sit on a long bolt that go across the width of the entire assembly and keeps everything together.

The GXSR has a fuel injector per throttle body, these are positioned so the fuel injects just behind the throttle plate – we decided that we wanted to retain the stock Megane F7R injector location (injecting the fuel into the cylinder) rather than going behind the throttle plate – so the GXSR injector ports were filled with chemical metal which is an amazing substance – once its dried it can be drilled, filled and even tapped.

Next was making a manifold assembly that bolts between the cylinder head and the throttle bodies – we took two aluminium plates – on one plate we machined the plate so that it had four holes each sized and spaced the same as the ports in the Megane F7R head. The other plate was machined to match the size and shape of the GXSR ports, and finally we welded four metal tubes between each plate.

To get the best torque from ITBs its generally understood that the runner length, the distance between the back of the intake valve and the start of the radiused entry, should be as long as possible. To gain extra length we manufactured, using left over tube from our manifold, four trumpets which, again using the trusty chemical metal, we bonded to the GXSR assembly, we shaped the end of the tube into a trumpet type shape to aid airflow.

The design decision we still need to make is what to use for an air filter – either individual trumpet socks or constructing of an air box for each trumpet to sit into using a standard performance panel filter. Critically we need to make sure that the trumpets have a cold air feed – the warmer the air going into the engine the less power it produces.

Due to ITBs producing unstable vacuum, a standard engine ECU  (which tend to use vacuum to measure engine load) would be very difficult if not impossible to remap, so the Megane is getting fitted out with a Megasquirt aftermarket ECU this will allow us to run in AlphaN mode which simply uses accelerator position (from throttle position sensor) vs engine RPM which will allow us to produce fuel VE table.

Once the ITBs are finally fitted and the engine is kicked up the final job is balancing them – you can purchase carb balancing tools cheaply on eBay – these consist of 4x vacuum gauges which you plumb into the vacuum port on the base of each throttle port and by adjusting the small set screw you can allow air to leak past the throttle plate – the idea being that each cylinder should create the same amount of vacuum to keep everything balanced.

Just a quick post as we finally got round to taking a picture of the vernier cam pulleys we’ve just fitted to the Megane 714 engine – note these are still to setup before we can finally get the engine fired into life.

One thing we’ve had to do to fit these pulleys is to manufacture two locking pins – the fast road cams we have fitted have two cut outs for a locking pin and the puleys have a hole in them for a pin to sit through, but unfortunately we could not source a pin (the standard Megane pulleys have a dowel fitted as part of the casting).

We ended up turning down a small round steel bar with two different diameters – the smaller diameter half goes into the tapered fit in the cam shaft and the larger diameter is an interference fit with the hole in the vernier pulley. The locking pin sits underneath the large bolt head in the center of the pulley so it is not visible in the above shot.

It’s been a busy old month here at TrackLogic – finally we managed to install our freshly rebuilt Renault Megane 2.0 (F7R) engine into its new home ready for the aftermarket engine management to be fitted (Megasquirt) using our in-house built ITBs.

The engine was removed from an 80,000 mile insurance write-off, soon after getting our hands on just the engine we started the process of separating the block and the head and concentrating our efforts on the bottom end.  As soon as we had the crankshaft removed, the real work began – all the journals had scoring marks, so the first job was sending the crank away for a regrind and ordering some new shells.

Whilst the crank was away at the machine shop, we started to take a look at the various oil and waterways in the block, casting slag was found and these were remove also the oil pick up was enlarged to promote better flow. Next on the list was the oil pump, this was overhauled with the pump housing being refaced to meet Renault tolerances and finally the pistons were de-coked and new rings ordered.

The block then had hours of therapeutic cleaning, making sure everything was surgically clean – not wanting to score our newly resurfaced crank after we got the block up and running. After what seemed like days of scrubbing, sore fingers (and at one point a sump in the bath – not a word to her indoors(!) we finally sent the block to the machine shop for a steam clean and degrease before receiving both the crank and block with various new parts, all greeted with a big grin on our faces – nothing beats the feeling of receiving shiny new engine bits.

We decided to paint the engine block in Hammerite blue, masking off all the various parts before giving it a couple of coats – it really transforms the look engine and is well worth spending a few hours during any engine rebuild.

Our attention then went to the cylinder head – luckily we’d found a fellow forum member that had a reworked Megane F7R head for sale – it had already been ported, polished and new valve seats reground – so we quickly purchased this and stored the original head away as a project for a rainy day.  The other great thing about the head is it had already been to a machine shop and a cut out made for a distributor should we ever feel like fitting one (the Megane F7R head is usually distributor-less, Renault opting to use two coil packs in a wasted-spark arrangement instead of the mechanical distributor and coil arrangement found on older 19s/Clios).

Our only modification to the head was to install some vernier pulleys and a pair of Kentcam Fast Road cams into the head, before we started the  reassembly process – as we’d made sure every bolt was screwed back into where it had come from, along with taking photos for reference, reassembly was  relatively painless process. Plenty of priming oil was placed on the cams, tappets and crank journals ready for that first start that we’re longing for.

Next months task is producing a custom wiring loom, ready for the initial fire up of the engine using a standard Megane plenum chamber to break the engine in before we switch to our ITBs with AlphaN control. ITBs due to the large area of the throttle plates produce very little vacuum so traditional MAP based engine management is difficult to tune and get right, AlphaN (which uses throttle position/RPM rather than vacuum/RPM) is the usual tuning route.

Catch us in the May/June issue of Performance French Car magazine where we talk about our latest Megane F7R 2.0 engine rebuild which our newly in house built ITBs are destined for.

Website moved to a much faster and UK based server rather than the previous US based host

See us this month in Performance French Car magazine where we discuss GPS laptimers using our TLDisplay and TLGPS products.

Lap timers used to be based on a radio beacon type system – radio transponders (or a collection of) were strategically placed around the track and by monitoring when a vehicle comes in range with the transponder calculations could be made to the vehicle speed around various sections.

As technology has progressed, generic lap timers (and devices with lap timer functionality such as the TLDisplay product) utilise GPS technology to provide much more accurate data – no more placing transponders – instead all you need to do is drive around the course and press the place “checkpoint” button at the points of interest. The lap timer will record your GPS longitude and latitude and use this in future for its calculations.

One thing to be aware of when selecting a GPS-powered lap timer is the “update rate” –GPS devices used in products such as satellite navigation systems tend to update the positional information once per second (1hz) – if you ever watch your Sat. Nav indicated speed as you accelerate or de-accelerate you’ll notice it lags behind – this is due to the update rate. For motorsport applications a GPS device with an update rate of 5hz (5 updates per second) or greater (10hz is currently the best) keeps this lag to a minimum.

Usually one check point is placed on the starting line, this allows entire laps to be timed, but by adding more points around the course individual sections can be timed – how quick did we go through the Jim Clark Esses at Croft?

Once the start line check point has been defined the lap timer device will keep track of the number of laps completed and of course show you have many laps remain. The display will indicate your fastest 3 lap times and your current lap time.

By comparing the vehicle position (obtained from the GPS information) in the TrackLogic DataViewer software alongside the lap times the driver can determine the fastest racing lines – add a tri-axis accelerometer box and the driver can also review cornering forces – a tyre can only provide a finite amount of grip before the car starts to slide – along with acceleration and deceleration times.

Lap time and positional information can be shared on the internet so you can see exactly where you are gaining or loosing time in comparison to other drivers – having records of your times can provide “bragging rights” – especially with the ability of automatically uploading your best times to your Facebook wall!