I need information about the technical characteristics of a Group N Opel Corsa B x16xe with an SBD ECU?
The Corsa group N system was originally designed in 1993 and was used by Steve Green to win class using a Corsa 1600 GSi in the RAC rally. The standard engine would normally produce 110 bhp. When the group N kit was fitted and tested with standard cast manifold, but with uprated downpipes and freeflow exhaust system, the engine produced 128bhp. The torque curve was much smoother and stronger than the standard engine, because the system uses throttle angle sensing instead of air flow metering. The throttle response was dramatically improved. The driver reported the engine was much nicer to drive in every part of the rev range and under hard acceleration. The group N system comes complete with a fully reprogrammable MBE9A4 ECU, a custom made wiring harness, modified idle control valve and a COIL-4. You would also be able to fine tune the fuelling and ignition if required, to suit your engines own characteristics and fuel available in your country. It could also be reprogrammed to accommodate any changes you may wish to make to the engine.
We have built a Vauxhall Corsa B 1.6 16V C16XE grA rally car a year ago, parts ordered from you, and since built we have overheating problems. The coolant temperature reaches 110 deg C after 5 km of special stage of any kind. At the beginning we had retained the OEM cooling system with the only difference that the heater radiator has been removed and the cylinder head and return hose sealed. While trying to cure the problem we have tried system cleaning, a bigger radiator, big fans but the problem remains. I would appreciate it if you let me know if there is an inherent cooling problem to these engines and if you could suggest any solution. We will try some more things like rerouting the cylinder head coolant exit (originally feed to heater radiator) but any suggestion would be helpful.
See the attached pdfs for cooling systems for the 2.0L XE, although it is not quite the same as the 1.6 XE it is basically very similar. Removing the heat would not create any problems. I would suggest a 70-deg thermostat (Do not run without a thermostat).
The customer also saw a big improvement by moving the oil cooler in the wheel arch and by directing the heater radiator feed hose (that was previously sealed) to the main radiator.
We have built a Vauxhall Corsa B 1.6 16V C16XE grA rally car a year ago. On this engine we now use a cams set with Inlet 12.00mm lift, 288deg, 3.7mm lift @TDC, Exhaust 10.5mm lift, 284 deg, 3.2mm lift @TDC. As the car is grA we need to keep the OEM inlet manifold and throttle body and the OEM exhaust manifold. The torque of the engine is 16.7Kg m @ 5200 rpm and the power 161bhp @7400 (rolling road test). Since the cams are relatively big but the peak torque rpm point is low we wonder if there is potential to this engine to move the peak torque point 1000rpm higher (as is the case with the Peugeot 1.6 16V engines) and peak power at 7800-8000 rpm so as to improve high rpm range performance, or there is something (for example the inlet manifold) that will not allow this.
We have not worked on Group A Corsa engines for more than 10 years, the intake system is the biggest restriction & is one of the worst we have seen. This is the part that holds the power back in comparison with better intakes, such as the Peugeot. We did use much bigger cams than you are using & although the engine produced slightly more peak bhp, in our opinion the engine generally got worse meaning less driveable. Unless you can replace the intake system, your options are limited.
Our customer replied: 'Thank you for your e-mail. The customer had said that he would use this engine for one year just to get familiar with the car and develop the chassis and then he would go for a kit car spec engine with throttle bodies etc. so we did not spend time flow testing the head, intake etc. But the data I had during mapping and then on the dyno showed that something does not allow the torque to go at high revs and cam timing changes affected low but not high rpm performance. We tried a bigger exhaust but things were the same if not worse. So the only thing that was left to blame (we had a bad feeling for the intake from the beginning ) was the intake which is very long with small chamber volume and many curves. Your e-mail confirms this impression. Thank you for your feedback.'