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go to hell Veritcal scope

6K views 58 replies 17 participants last post by  crazybroncoman 
#1 · (Edited)
#10 · (Edited)
cant leave that shit alone can ya? if it werent for that we'd be going to riverrock next weekend :smokin:

ahh well, reckon we will make it to june jam... hell maybe by then i will havw my beadlocks, cromo shafts/joints, slugs, and GLO diff cover all installed!!!



hey... a man can dream :flipoff2:

-cutts-
 
#12 ·
think it would be worth changing to the thicker gasket i stated above?

is the 12.98 the comp ratio with my curretn gaskets and the piston top ring volume?

i talked to propane guy(cary) and he said hes heard of 12.5 or so successfully but couldnt remeber if he has ever heard of 13:1 being done? lunati cams tech guy said go for it???


are there any other dangers of running 13:1 on a trail motor??



i hear ya cutts, you know me i cant leave shit alone...
That was with a .040" head gasket thickness. If people get away with 12.5 and youve got a "big" cam, id say it will be ok.
 
#18 ·
dynamic with thick gaskets is 10.32 with current gaskets its 10.952

i just want as much power as possible, thats why im debating the comp ratio...but theres not much info to be found on what you can do on a propane powered motor, its all wishy washy

i think im going to swap out gaskets at summit tomorrow and go witht he thick ones to give me a static of 12.39 and dynamic of 10.32 (thats without using that top ring calc you spoke of)
Without calculating that volume, your not getting an effective compression ratio. After all it is part of the combustion chamber. www.diamondracing.net is that calc I am using.
 
#23 ·
dont run a thicker gasket, you will lose quench and will probably have worse detonation issues than if you didnt. how is your deck right now?? zero?? out of the hole?? you are better off changing the cam or just pulling a little timing. personally i think you will be fine at 13:1 if the propane is actually 105 octane, im running over 11:1 on 91 pump gas in my 521 with .040 quench and flat tops, A-460 head and 34 degrees of timing, no detonation. Also, keep it cool and that will go along way as far as detonation goes. this isnt a fucking chevy with big shitty chambers that dont burn worth a shit and ping like a bastard.
 
#24 ·
can someone explain the basics of quench to me? ive done alot of reading about it but ive never been able to quite grasp it

When you say how is my deck...do you mean how is the piston in relation to the deck of the block??

if so its a little out of the hole...i havent measured anything...the flat part of the piston is .025 below the deck and the dome is .4" i think??

keeping my junk cool has never been a problem, i run a large horsepower robbing mechanical fan with clutch and fan shroud....never had a problem

thats part of the deal, some people say propane has 100, some people say 104, some say more, i havent been able to find a clear answer on the "octane" rating
 
#25 · (Edited)
Squish clearance has to do with creating turbulence and allows for a more complete combustion. Thats what I have read, I would like to know more about it though for those who know... If I had to guess the tighter the squish band, the more spread out the mixture becomes, allowing for a more complete and balanced combustion...I read that in a race engine the closer the squish clearance the better, and at high rpm you want it as close as possible. You have to factor in rod stretch and all that though.. crazy
 
#26 · (Edited)
editing in progress***


quench (or squish) is the distance from piston at TDC to head.
it's the perfect size air bubble in your compression chamber. when you squish that air bubble JUSSSST RIGHT it sends a shockwave (think of the *NOISE* of a balloon popping) down the combustion chamber that helps even the temperature of the block. i believe it has to do with resonance (like VRIS in an intake manifold)

BUT!!!

you are getting WAY too involved in engine building specifics for what you are actually considering doing. if you are seriously going to run one OHGX450... then you're not building a frickin race motor. so as long as your compression ratio is north of 10:1 you don't need to concern yourself too much with all that effective ratio stuff.


1:accepted optimal CR for LPG is around 11:1

2: squish, swirl, valve steps, shrouding, wet-flow, and turbulence can pretty much be thrown out the freakin window... you don't need to vaporize your gasoline between the float bowl and the piston. your Pane IS vaporized, and at 11:1 your mixer *tuning* and spark advance will control detonation very well.

3: you should be most concerned with a complete combustion event and opt for dished pistons to facilitate. i STRONGLY suggest having your (hypertectec) pistons, chambers and valves pollished. all those reflective surfaces will bounce that heat right out your exhaust. *side note- polishing all these things averages a 6% increase in HP.

4: 160* thermostat at the highest... make sure you have a glycol%, radiator, and enough CFM from your fan(s). some things (besides all the polishing) to help keep your temp down : eliminate EGR. use an aluminum intake like performer RPM that has eliminated the heat cross-over.




here's some clear answers for your pane questions...

the effective octane rating of LPG is 103 and you will get similar *performance* using LPG vs. gasoline
BUT it has a lower energy content (Propane contains about 84,000 Btu/gallon and regular gasoline averages 114,000 Btu/gallon)
so your *mpg* will drop, depending on load. at optimal load you will lose .08% MPG... but, once you put that pedal down to pass a blue-hair, or climb an obstacle, your MPG is going to drop much faster than .08%

if you're running forklift tanks, you are choosing between 10 and 16 gallon tanks. you're not getting very far with that. those tanks cost you between 100-200$ each.... how many do you want to buy and carry around?

but i keep coming back to the initial remark i made...
why on earth would you run ONE X-450 on a 472 when most% of people aren't happy with ONE X-450 on a 350 with decent HP #s!?!?!?

the ohgx450 is rated at 435CFM... can you IMAGINE putting a carb like that on a bigblock? granted, cfm means different things for gasoline/lpg...

you need to figure out your engines cfm demand at a given rpm... if it's ever OVER 435, then you are going to SUFERRRRRRRR anywhere faster than that RPM. do that, and i'm sure you'll see why you should go with a dual mixer setup. they will of course be smaller mixers, probably giving you ~300cfm each.
 
#29 · (Edited)
ummmm yeah... except there are some good pane forums with gurus that have as much knowledge in building for pane performance as the gurus on pirate4x have in rockcrawling.

i would have given him the same advice if he was strapping the motor to a red-ryder to compete in some backwoods-beer-blitzed-wagon-race.

for basic questions: http://fuelsforum.rasoenterprises.com/viewforum.php?f=5
 
#30 ·
Really? Guys aren't happy with one x450 on their small block? Who?
I've got a ton of customers running some pretty hot motors on one mixer. 383 strokers, a 350 that runs over 7000rpm all day, big blocks over 500 cubes, etc.. They will make 500hp and short bursts even higher. AK Miller, the one who designed this mixer, used to run one mixer on top of a supercharged 350 until he passed away.
 
#33 ·
just stating what i've heard from guys running 400+hp smallblocks. most of them aren't happy.

and supercharging or turboing totally changes the ballgame when you are talking about mixers...

i respect your company and what you are trying to do... but it's a simple question of cfm that a 472 is going to demand. without calculating for his specifin engine, i'd speculate it's going to fade HARD around 3500-3750RPM

that's only based on #s i recall for a 400ci needing the maximum cfm of an X450 at just 4000rpm
 
#34 ·
I guess my point was it can flow enough air to do it. It was a draw through setup. (carb on top of blower).
 
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