How to limit red line?

Asking about on red lines I've got some scope of insights and sick humor.
Likely the heat soak of WOT on air cooled Twin would spell
the end even if kept below normal red line by tall gearing, ugh.
But for that there's water spray or even liquid CO2 to help.

Factory 750 set up for 7000, 850's 6800 in practice. Factory
heads tend to float and clash after 7000.
920 cc road race Norton based engines are limited to 7200.
Essentially stock bottom and parts 850 with lightened crank aka
TC dual engine shifted at 8000. 750 desert racers survived
8500 and I've a few separate tales including one of my own of
regularly hitting 9000 for short spurts in specials.

Ms Peel engine head is good to over 10,000, tested fine even
on the severe jerking it got as cam chain and cam lobe torn up loose..
Crank is as stout and sling mass shifted as the 9000 kind.
The pistons new lightest available and 1/2" longer rods are steel
yet lighter than factory Al rods. Cryogenic tempered barrel shaped
roller bearings to take up some crank flexing. Inch thick Maney race
cases to take the slinging inside. All fastened by over size AN bolts
and or Timesets in Al. Will also cable down the dang head to the
mounts. Boost on top of piston intake decent relieves crank flex
and piston acceleration stress some too.

10:5 static CR + at least 10 PSI boost @ 7000 calc's out to like 17:1.
Should flat explode w/o 112+ octane to stand best spark time pressure.
Even so squish bands, which are at least double area of factory heads
must be kept close to actually quench. I think squish band impact will limit
rpm before other parts give up. Nortoneers report it takes over 7000 to
close up-kiss.a .035" squish with Al rods. So Peel engine might be ok
to 8000 for all out mania tests. If so the blower curve rather steepens
over 10 PSI and so do the power calculators zoom up. Max port Mach
number by calculator is low .7's, ie: about 3/4 way before sonic choke
back up so should keep on increasing torque even steeper. No sense to let off!

I will put witness objects at ends of crank for creeping up on that
flex that hurts whats attached like cam, oil pump and blower drives.
I will work up rpm by rev limiter then pop the top and look close.
This is one shot last dream project so don't/won't have time if
smithereens stupidly. Not yet got piston acceleration tolerance data.

Here's about as good as it gets so far. My teeth grit to listen.
http://www.youtube.com/watch?v=S509LGFabCw
How the hard hearts really use them to go down fast, if ya can stand it.
http://www.youtube.com/watch?v=IhLEJxpW ... re=related

hobot

Hobot asks the forum "How to limit red line"?


Well, I guess some sort of rev limiter could be set up to help Hobot out with all this newly anticipated power he has planned.

What could help Steve?

Some sort of ignition shut off tied to rpm perhaps?

What can we suggest to help out here so Hobot does not over rev his new motor, when he gets it done someday?


Personally, I just watch my tach, but that's just me, probably much too simplistic of an answer for Hobot.

Pazon have programable rev limiters is their more expensive options.

Aw shucks fella's I've been here not quite 2 years but Peel's engine been in process for 6+ yr now. Two factors missed by those not familiar with dragster responsive engines, only takes a bit of throttle sticking or missed shift to over do it and they can rev up so fast throttle hand can't always back off in time. Peel has digital program ign with adjustable rev limits, 4 of em, just not sure where to put a stop to it w/o stopping power climb too short. Some powerful egnines go zaarrRRROOOMM, others baLATTT!

[video]http://www.youtube.com/watch?v=QLo2fxfU4w0&feature=related[/video]
[video]http://www.youtube.com/watch?v=9-pwa_uVNEs[/video]
[video]http://www.youtube.com/watch?v=hrPE0qSxHkU&feature=related[/video]
[video]http://www.youtube.com/watch?v=3pWBv7WrnXw&feature=related[/video]

Convert it to . SIDE VALVE . :lol: . Used to be centriugal cut outs , but a bit suss . If Electronic with a computor
it shoulnt be too difficut . Well have you building computors next . :? :wink:
http://www.youtube.com/watch?v=yH97lImrr0Q
http://www.youtube.com/watch?v=dhxL5xbL ... re=related

There are voices in my head and they are not mine. Hehe haha Hoho the weapon cage worked out by 3:30 am wonder if I can out run the projectiles?
[video]http://www.youtube.com/watch?v=oQcSCq8gqKM&feature=fvwrel[/video]

well since you are going to boost 10PSI (supercharge) I would think, based on my years of autocrossing ( MGB) and a few club championships that the cam becomes the ultimate "regulator".
I built as fully ported high RPM high compression road race engine with a mild torque cam. I ran it for many seasons and won many trophies in the unlimited class agains all comers.
This is actually my view for my future hot rod atlas. The cam will be less than combat but all the rest especially compression will be way up there. The whole exercise will be about the ignition curve....on high test... pump gas.

I would say that the fact that your engine has been "in progress" for over 6+years, with no end in sight, is, in and of itself, a rev limiter.

Diablouph said:

I would say that the fact that your engine has been "in progress" for over 6+years, with no end in sight, is, in and of itself, a rev limiter.

Click to expand...

Big ole +1

Hey Dyno, I accidentally did your small port head on Combat idea and once the megaphone adjusted by 12 ga shot gun I became a sports bike hunter and quickly got back my ole P!! dragster reflex to lock to bike at lower speeds before snapping throttle. I want to out leap the current crop of elites to over 150 mph so scratching at straws to get away with it yet its more fun and more routine for me to be off roading on loose stuff than skiing tarmac in public, so had to clash Peels cam profile for tame bottom range yet spikes torque by mid range on. Norris D+ drag only cam is the best I could come up with off the shelf. Ideally would need an assymetric grind with emphasis on the exhaust opening rather than the forced intake side. 20% bigger engine tames aggressive cam made for 750's. Small valves and ports for the 920 size also tame aggressive cams. Having some positive pressure on intake also tames aggressive cams. Norris D's late inlet closing lowers effective CR to ~7.5 in hopes it'll let me kick it off and not just spin out on easy throttle nor require 112+ octane just to piddle around. Peel has
a cam door to inspect and replace over the years till i get it right or really wrong.

Drouin boost amount is a nebulous sliding scale as mainly depends on how fast one can load engine. Feathered throttle should lug like a trail bike w/o boost but fast throttle will leave me in spinning in place or tripping out at will. Don't think I'll need full rpm but for dyno or land speed or drag strip, not regular use or track days or Pike Peak pecking order. Still a bit depressed they paved it all now.

Engine has been delayed d/t cost, broken necks and new features as they come to my attention. Oil jets, rifle drilled cam and oil feed are about all left before engine sent home. Mean while configuring Peel for deer and crashing w/o harm to full fairing and suspension height system and 2nd oil supply. I'm lucky to be alive while others ain't - so life is 24/7 surreal so taking my time savoring the journey. Oh yeah also delayed a month figuring out compression releases so expect more delay to try install on a standard head then Peel's.