rivercrazy

I usually just run '87. I read somewhere that any lower than that can damage your motor but any higher doesn't really help on a low compression motor (other than maybe some added cleaners).

5-90

F1 is usually a very undersquare engine, with like a 2-1/2" stroke. Shortening the stroke that far lets you wind it up farther.

The RX-series engine (as well as the Mazda Cosmo, and the old Rotary Pickup) are Wankel Rotary Engines - as mentioned, there is no crankshaft. They use ovoid chambers and eccentric rotors, and picking a "redline" for them is a matter of finely balancing them. 'Way back when, when I was still building strip engines (playing with staged forced induction and exotic fuels,) I was in an informal competition with a guy who specialised in Mazda rotaries. He was working on pushing the redline of his engines - twenty-odd years ago, when we were doing this, he was balancing them to spin 30,000rpm all day long (yes, it's doable!)

Myself, I prefer long-stroke/long-rod piston engines now, due to the higher torque at lower crankshaft speeds. I'm more into torque than horsepower now anyhow. But, I also have fond memories of building a Hemi with pop-ups, running a pair of turbos into an 8-71 to shove in about three atmospheres, and running the damned thing on a cut of 120LL and toluene (damn thing would ping stupid running on anything less than a calculated 125 AKI!)

sv41878

Haven't had a chance to look for the ticket, but 30k rpm. Oh that's sweet, where can I find this guy?

ZachsXJ

IMO this whole thread is full of win. 30K rotary engines. HEMIs that require 125AKI fuel to run properly due to 44lbs of boost :P

5-90

He's probably retired, but he was in central Indiana. Lebanon, IN, I think (on I-65, about halfway between Lafayette and Indy. I grew up mostly in Lafayette, with a bunch of time spent in Monon, Monticello, and Yeoman. Born in Monticello. Still have family in Monon, Yeoman, and Terre Haute - if you meed a "Diggs" in Indiana, I'm probably related.)

@ZachsXJ - 45psig of boost isn't really that much, compared to some I've seen. Top Fuel dragsters compress the air-fuel charge almost solid at TDC. I've seen Diesel pulling engines (tractor/truck pulls) running staged supercharging at 7-8ATM of boost. There's not much of a limit to what you can do - when someone else is footing the bill with deep pockets!

Consider that I started doing mechanical work when I was six, built my first engine when I was eight, and started making extra money doing mechanical work when I was twelve. I learned theory to go with the practical, and that opened up what I could do - I started building strip engines before I could drive (I was fifteen. I wasn't totally out of vehicles - I'd been flying for a year. Besides, I was big for my age - I'd been driving since I was twelve.)

I never got into the rotary scene, but I'm sure there are still people out there who are very good at it. Or will be again, now that the Wankel is making a comeback with the RX-8...

ZachsXJ

Well yeah, when people have ridiculously deep pockets 44lbs of boost is nothing. My buddie's dad has an F350 7.2 diesel that makes 44lbs of boost easy. Diesel engines can take a ridiculous amount of boost because of how they're built, I would LOVE the opportunity to drop a 4BT into my XJ if I could somehow afford it. Diesel engines are so much more practical than gasoline.
A top-fuel supercharger car makes an average of 60lbs of boost and up to 75lbs. Like I stated before, if you have funding from a big company the limits for what you can do go way up.

rickybarth

yea if you get a ticket for doing 220 your probally not going to be driving for a while and deffinentyl wont have your car

itsanxjthing

Lets just all get jobs with popular nascar sponsors, then convince them that rockcrawling is a legit sport, so they could sponsor rockcrawling.

84wagoneer

ever ridden a sport bike? 16k is a beautiful sound. the high rpm's are hard on the motors too, theyre usually miled out at around 50k. cheaper to go buy a brand new one off the lot