[QUOTE=articfriends;4533411].....Official done testing anymore carbs on this engine, giving all carbs back to their righful owners and even drug out a few good carbs i own and put them on ebay because IF i ever put a carb on anything of mine again EVER which i probably wont do i would just give norm a stack and say build me one! Now on to efi if my parts ever show up! /[QUOTE]

I don't know about that. Carbs are wonderful devices. Simple and you can pretty much make them do anything you want with a small handful of brass parts. For marine use, about the only negative (and it is a big one) is that they can fill your engine bay full of gas vapor. That's a pretty big argument in favor of EFI right there though.

I love what you're doing here. I really like the fact that you are doing it with a real world (low compression) engine and not something requiring avgas or whatever as the ultimate shootout engine. I like your attitude of building an engine that can reliably run 20 minutes at full throttle. And then do it again. Endurance race engines might be the toughest to build.

Thanks for sharing your research. I'm really enjoying it.

Dan

Post #63

Unless you raise the injectors up in the runners.. not at the base like they usually are. Think Nascar of today....Old news that has been used in Formel1 and tintops since 60's. Stack injections wake up with on top injection and a plenum on top... sorta like putting a Big plenum on top of a tunnel and injectors there in line above throats.

Chasing 17-20,000 rpm gives you really short intake tracks!

Look how tiny that clutch is, and how low (close to the ground) that allows the crankshaft to be. Just beautiful.

Look at how many plates that clutch has.... Short runners or not (those are variable) Never Ever put the injectors washing up the valve stems from lube like it is the norm for OEM engines... Just look at every injection, even mechanical form early 60's including Crower ( which was what KAM used) back in the day. * Thats why Carbs usually beat EFIS for top hp...

FI on performance motorcycles were a step backwards powerwise for a while until they put a second injector further upstream in the intake, and that was a major game changer. I have never once heard any racer say that they miss carbs after that. Are there two stage injectors on these bigger motors?

Last day of carb testing, was going to be done BUT norm and i decided to do what we could to straighten out f2speedy/33outlawsst's cs carbs. Norm calculated what size the power valve feed resttictions would need to be to get a nominal increase in flow when power valve opened so we could jet his primary main jets leaner but still get enough fuel flow at wot to support his hp goals. So we opened up the feed holes with a #47 drill and went down 7 sizes on primary main jets. His cs carb made good wot hp at a safe afr BUT having to use a #93 main jet put afrs into mid to low 11s when i dragged the dyno brake at 2800 to 4000 from 250 to 375 ft lbs. After the mod of course we had to see where we were at on dyno. With power valve closed at a part throttle load we were now able to get mid 13s and then go richer when you leaned on it at wot. Previously it did the opposite! Called it a day, looked at afrs at 5500 rpms and about 625 hp load and decided what jets HIS carbs would need for safe starting point. Im quite impressed w norms nowledge and ability! We slapped a prototype carb on that norm built and is experimenting with, did a few adjustments then called it a day! All efi stuff happened to show up today, starting to bolt all that on Tommorrow! Btw, check out the adjustable cam linkage norm built for progression rate of secondarys!

Prototype carb he built, notice anything missing?

Everything. Where are the mister thingamajigs? Never mind the choke and J-tubes. ;)

Missing MORE than that in appearance