Renault 5 GT Turbo E.F.I.

It all started with the idea of having a reliable engine able to make 200hp+. To get this without a high boost setting, the camshaft timing and valve lifting had to be increased, leading to an irregular idle, poor low rpm torque, increased turbo lag and the added difficulty to setup the carburettor.

So in order to minimized all the bad things and get some extra good things...why not fuel inject it? We came up with the idea of using a simple and not too expensive ECU, the Webber/Marelli IAW045.01 from a Ford Sierra Cosworth 2WD.

The electrical was also modified, reducing energy losses, minimising consumptions and rewiring, were the major objectives. Of course if you take off some redundant devices, such as the rear windscreen wiper (and motor), all the related wiring will come off too, meaning... less weight... a two-in-one operation!

With all this we expected to have a powerful but still easy-to-drive street car.

The picture is an old impression of the car, with a few bits missing, before this projected had started.


Early setting

The hp at that time with all major engine components standard and with the original turbocharger set to make 1bar (168hp).

Timing the camshaft

The camshaft was carefully timed by our mechanical engineer, L. Coa with the help of J. Martins (electrical design and advisor) and P. Vicente (the owner) .

We had some problems with the setup as there were some small discrepancies between the datasheet that came with the camshaft and the one on the suppliers website. But in the end we did find the proper setup.

Flywheel modifications

The difference between the original (left) and the altered flywheel (right). The clutch plate holding pins had to be taken out and repositioned.

Rpm sensor and alternator belt

The IAW045 ECU uses two sensors to determine rpm and injection sequence. One of these detects the presence of four 90 spaced teeth placed on the crankshaft pulley, so a metallic plate was made to the necessary shape (+).

The R5 has a bit of a problem with holding alternator belts in place at high rpm due to the distance between the water pump and crankshaft pulley. To keep it in place a small pulley was placed just above the crankshaft pulley. The belt can now be tensioned without having to use the alternator. 

The alternator

As part of the idea of taking inertia of the engine and since the electrical was going to be more efficient, the standard alternator was replaced with one from a Suzuki Swift. The smaller part also allowed more room for the intake tubing that connects to the upgraded intercooler and since the alternator has an independent connection for the battery warning light and ignition feed, a switch was placed on the throttle body to cut off the ignition signal to the alternator when in full throttle, this makes it stop charging, leaving a bit more power to the wheels.

Intake manifold

The manifold used for this conversion came from a car that was a strong competitor of the same category as the R5. We did some resizing and welding and it fits perfectly! After questioning the size of the original throttle body versus the required air mass to achieve the 200hp, we decided to replace it with a bigger one (61mm diameter), from a Renault Clio Sport phase1. The set of four injectors came from a R21 Turbo.

The turbocharger

This unit is a Garrett GT28R Dual ball bearing.

Making the down-pipe

Since the exhaust manifold and turbocharger were upgraded all downstream exhaust was also altered to get a wider and smoother tube curving, plus the increase in diameter to 3inch (~76mm), all the way to the back end.

The engine bay

In order to keep the engine bay as cool as possible, an exhaust heat wrap was placed on the custom exhaust manifold, at this time the positioning of the down-pipe was still being tested and so, no yet shown on the top picture. The soft-clutch modification kit can also be seen here.

The finished down-pipe in place. The close proximity of brake lines and water tubing, made this a bit of a challenge!

more to come...