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 from a Ford Sierra Cosworth 2WD, which was easily available. The electrical was also a target for changes. Reducing energy loss, minimising consumptions and rewiring, was the major objective. 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 car. The picture is an old impression of the car, with a few bits missing, before this projected had started. |
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Early settingThe hp at that time with all major engine components standard and with the original turbocharger set to make 1bar (168hp). | ||
The camshaft was carefully timed by our mechanical engineer, L. Coa with the help of J. Martins (electrical design and advisor) and P. Vicente (car owner and sponsor) . 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 eventually we did find the proper setup. | ||
The difference between the original (left) and the altered flywheel (right). The clutch plate holding pins had to be taken out and repositioned. The opposite side was also worked out. | ||
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 pulleys. To keep it in place a small pulley was placed just above the crankshaft pulley (see picture). The belt can now be tensioned without having to use the alternator. | ||
As part of the idea of taking inertia of the engine and due to a more economic and efficient electrical, and of course overall weight, the standard alternator was replaced with one from a Suzuki Swift. The smaller alternator also allowed more room for the intake tubing that comes from upgraded intercooler. There are a few more tricks related with the use of this device but at this time I am not allowed, by the sponsor, to disclose them...sorry! | ||
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 mark, 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. | ||
This unit is a Garrett GT28R Dual ball bearing. | ||
Making the down-pipeSince 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. | ||
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.
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| more to come...
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© 2006 RPM