We were pleased to be appointed as the restore the Ralt RT32 / 778 by a long standing client and owner of a number of historic F1 cars. The car had spent much of it's life in Japanese F3 and came to us in need of full restoration. The RT32 was a car developed for the 1988 season and this one was a good project to restore. We were able to purchase a Nissan CA18 engine along with the car and set to work. In discussion with the client we decided to go with the famous Marlboro colour scheme
The engine underwent our normal in depth assessment and rebuild with modifications as necessary. Our in house engine specialist comments on the project as follows:
"The heart of the Ralt is its CA18 engine. An old engine some might say, but one incredibly good for power and found more often these days in drift cars and high Power turbo cars. The Nissan engine originally would have been 1800cc although 2 litres blocks were later used.
We stripped the engine on receipt of the car. To work out what we had, what condition it was in and what we could reuse.
We ended up with a bore size of 85.50mm. combined with a stroke of 83.6mm which was going to give a 1916cc capacity. We could not justify boring any more as the pistons were custom from Diamond Racing in the US and were in excellent condition. The rods also were forged, in good condition with a length of 136mm, just like Honda B18 rods.
The valve pockets and piston crown gave a small volume of 0.55cc so the deck height was reduced to 203.3mm. Combined with gasket and head this would give a compression of 9:1
We used ACL Race series bearings and ARP for Bolts throughout.
On the cylinder head we gas flowed and made some improvements and ended up with ports that flowed 240cfm. When matched to a good inlet and exhaust system, this should be good.
The cams had a lift of 9.8mm which was not massive, but it gave good piston to valve clearance, the duration on the cams too is not great at 235 deg. However you soon find out that these engines work with little cam duration due to the large valves and flow rate. This was useful in deciding our finally CR as above, as with such a short duration cam the dynamic CR would still be in the 7.8 area.
The head gasket was Cosmetic (MLS) and the STD Vernier pulleys were used.
The car was on an Onyx Ecu which we opted to keep in view of simplicity and long inlet runners and a slider throttle body. We also had a good size exhaust manifold which we opted to re-use.
Ignition was from the Onyx Ecu and wasted spark via a Ford coil
We ran the car twice on the rolling road, the first time we ended up a bit low on power but after some adjustments the final number was 227bhp at 7000. Pretty good by any standards for a Normally Aspirated CA engine.
Out on the track, the car seems to keep on giving and is an experience to drive with its little weight. The power to weight ratio is better than any street turbo CA"