quote:Originally posted by Geeto67
with the technology that is out there now turbo is they way to go. Fuel Injection would also be the way to go. What wasn't around in the 1970s was variable electronic ignitions, boost controllers, and cheap FI parts that make 20 bls boost turbos viable where as the old setups would pull 6 to 8 before you started to lunch stuff. Turbos need a significant amount of timing retard at higher RPMs that just wasn't there with mechanical advance and points.
The one reason a supercharger was more popular in drag racing is it doesn't require you to pull as much timing out at higher boots levels and you can retard you stock system to enough at idle to compensate for like 10-12 lbs. A lot of drag racers used the drouins and I ahve yet to ever hear of a crank failure, and a lot of those guys ran lightened cranks. I do remember an old timer telling me about the hondamatic cranks being popular to use in the cb750 blocks for really stout big bore supercharged motors, but that involved a lot of work.
Supercharges always run in a fixed ratio in relation to engine speed because they are driven off the engine. Turbos run in a variable relation to the engine speed because they are exhaust driven - with turbos boost is controlled by a waste gate and/or boost controller because there is no way to adjust the dive mechanism to make max boost at peak hp. Output on a turbo increases exponentially in relation to engine speed.quote:Originally posted by HackAsaw
I find the timing assertions bizarre.............
with any boosted engine you need to run lower compression. When we put the eaton roots blower on my father's Harley, we needed to drop compression to 8:1.quote:Originally posted by bmartin
Geeto - I believe with a turbo setup you need to use lower compression pistons. Something like 7:1 instead of 9.5:1. I'm not a turbo expert but I've read about turbo powered hondas for years and they look really sweet. With a turbo honda, are you going to kick some new 600/1200 sport bikes ass - nope - but it still it would be a cool project.
No, it had no advance or retard and was strictly a drag racing unit with fixed timing(no box, or anything, timimg would stay the same all all RPM). It sure looked nice and shot a 2 inch spark, but the Dyna was more useful for the street.quote:Originally posted by HackAsaw
Fischer........ are you saying the Mallory Sprint mag, once on that bike, had an auto-advance unit?