Regardless of horsepower ratings, the Opels are not as powerful as we´d like. This is the down side. The up side to this is they are relatively easy to improve in terms of proportion.
Early high compression engines are rated at 102 gross hp, and 90 hp net. Figure around 80-82 by today´s standards (at the flywheel, not at the rear wheels)
Later smog engines were pathetic. They were rated at 90 hp gross, and 75-78 net (depending on year). This is about 65 hp by today´s standards. A car magazine dynoed a smog-style Manta on a chassis dyno in the early 70s. It made 47 hp to the rear wheels. This is pretty accurate.
All is not lost however, I was able to get 97 hp from an early 1.9 with simple bolt-ons. This equates to about 20% more power than stock, and knocked 4 seconds off my 0-60 time (from 12.4 to 8.4). Top speed increased 18 mph.
I dynoed an engine I built for a friend of mine, it was a 2.0 litre that made 155 hp at the crank, with no air filter, and one muffler. With a restrictive air filter in place, and three mufflers to quiet it down, it made 114.7 hp to the rear wheels (over double that of a stock smog engine), through a Getrag, a limited slip, and tall 15 inch rear tires. The coast-down measured the driveline power losses @ 17%.
The *reasonable* streetable limit for a 2.0 or 1.9 Opel engine seems to be about 140-150 hp, any higher starts to really tax the pocket book and the driveability factor. The larger Opel engines with the better cylinder heads can make over 200 hp for about $6000 or so, and still retain driveability. I have a 2.2 litre that idles smooth at 900 rpm´s with dual Webers, and made 224 hp. Another friend has a 2.5 litre Opel engine that makes over 185 hp, but idles like a stocker, and pulls from idle to 7500 rpms, all with a single carburetor.
Now with turbos or superchargers, the sky is the limit, as long as you have cash to spend. The same person above with the 2.5 litre has asked me to build a 2.7 litre turbo Opel with programmable fuel injection. Preliminary estimates based on a Garrett engineers turbo recommendations, are 320-370 hp depending on fuel octane and boost level. But this will cost over $8000 to build.
This is wheel HP. If we assume 17% loss it's 128.4hp at the crank. Now that the fuel system is fixed and I won't go lean at ~5500rpm and based on peak hp at 6500 rpm I'm expecting another ~20hp. We'll see...
It looks like your maximum torque was right around 12:1 air fuel ratio. You have a lot to gain if you can tune the the rest of the RPM range closer to this mixture. Make sure to check your EGT at this mixture for "safe" operating temps.
I'm looking at a 72 1900 that I am told runs great at higher RPMs, but does poorly at lower ones. It sounds like it was set up more for racing than driving. I would like to use it for casual driving, not racing. Any suggestions on how to tame this thing? Would going back to a "stock" Weber...
Well I know there are a ton of threads on all kinds of builds and opinions but I thought I would start a consolidated thread on building a 2.5 to 2.7L engine for my 70 GT restoration. I'll be working with Charles Goin extensively on this build over the winter and hope to have this baby running...
Just wondering if anyone has the dimensions for the mounting holes for the CIH flywheel/crank
Need the pcd, hole sizes and the offset angle for the positioning/locator bolt if anyone has them, and any other dimesions come to think of it!!!
Decided to have a crack at machining up my own...