Landracing Forum
Tech Information => Technical Discussion => Topic started by: 38flattie on December 27, 2012, 05:17:26 PM
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Ok guys, I know nothing about nitro, but NEED to! :-o
In our quest for 200 mph with the flathead, we'll be running on fuel. Any pointers on the use of nitro with a blower is appreciated!
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More is better. Tony :cheers:
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Start building your back-up motor.
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More is better. Tony :cheers:
The whole saying:
"A little is good, more is better, and too much is just enough." :-)
Regards, Neil Tucson, AZ
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its hard to get "good" information on the stuff if you are planning on runing low percentages, all the top fuel knowledge is based on 90+ and is "totally irrelavent" to anything less,, my experience/advice is to sneak up on it, increase in small percentages, moniter, and keep notes,, from around 30-40*, everything tuning wise changes bigtime the more you tip the can,, :-)
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Buddy, you're just bound and determined to blow that pretty motor up, aren't 'cha? :wink:
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Ok guys, I know nothing about nitro, but NEED to! :-o
In our quest for 200 mph with the flathead, we'll be running on fuel. Any pointers on the use of nitro with a blower is appreciated!
What Stan said, and double your budget depending on the percentage of Nitro. I wish you the best.
Tom G.
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Start building your back-up motor.
loloutloud.
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Do you fee obligated to kill your project in 2013?
BLOWER? FUEL? OK!! But start with alky.
In science courses in college the rule was to make one change at at time.
If you don't you won't know what killed the engine.
Don't try to learn it out of a book. Get someone that can assist you
that has had experience with supercharging and fuel.
Use the money you save and buy cat food.
For the first time in my life I am organizing a Prayer Circle: just for You.
FREUD
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You guys are making me laugh!
....and a whole lot nervous! :-o
Buddy, you're just bound and determined to blow that pretty motor up, aren't 'cha? :wink:
Chris, I DON'T WANT to blow it up, but pushing it to 200 mph is no easy feat- some parts may have to be sacrificed to the 'Salt Gods'!
Do you fee obligated to kill your project in 2013?
BLOWER? FUEL? OK!! But start with alky.
In science courses in college the rule was to make one change at at time.
If you don't you won't know what killed the engine.
Don't try to learn it out of a book. Get someone that can assist you
that has had experience with supercharging and fuel.
Use the money you save and buy cat food.
For the first time in my life I am organizing a Prayer Circle: just for You.
FREUD
Aw, it'll be alright-or not! :evil:
I'll gather everything I need, study up on it, then take everything to John Beck. We'll dyno it with the gas setup, to get a baseline.
After that, we'll tune it with alky, and see where we're at, and add the juice until we get 800 HP, or need the kitty litter! :mrgreen:
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Just a few basic parameters: I built my 496 Dart BBC to run on 30% max Nitro (unblown) using 12 1/4 to 1 Compression which is as far as I feel is safe for 30% (okay, what the hell, lets make it 35%)!
Basicly, I used a Dart Big M tall deck block with billet main caps, ARP main studs, Callies Crank, Carrillo rods ($2200 a set), JE pistons, Barnes six stage Dry Sump oil pump, external JK water pump, Donavan Gear Drive, front driven Mallory Mag IV, Comp Cams Cam and Roller Lifters, Jessel shaft rockers and 7/16" pushrods on Dart Heads, using ARP head studs, Cometic Head Gaskets (MLS), and NO O-Rings head to deck. I use a Edelbrock tunnel ram with a Enderle hat and a front drive Enderle pump.
Now add up the cost of those parts and keep in mind that every four runs I get to remove the $700. pan to replace the rod bearings and now you are in the ballpark........
NOT INCLUDING THE BLOWER which you better be ready to restrip every four or so passes.
Add in a new blower belt every few runs, and don't forget that the oil in the engine (I run eight gallons) must be changed every pass because of dillution.
Now if you have the ball's to fire it up, try to remember to back the motor down first or your new blower and hat will be in your neghbors yard or living room, and you will never hear clearly again.
Oh, once it fires, you are doomed................. nothing (except maybe Beer and Sex) will ever be of interest to you except....................... NITROOOOOOOOOOOOOOO!
One Run Bob (maybe 32% should be where I stop) :roll:
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I wonder if Austin Coil is bored and ready to destroy something? He always put his thumb and forefinger together in front of Force's w/sgield just when he wanted John to stage the car. Force said that he figured out that the sign meant that he had zero chance of getting to the other end without being on fire. A couple of backup motors will be a good idea. I think alcohol would be a good start.
Doug :cheers: :cheers: :cheers:
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Just a few basic parameters: I built my 496 Dart BBC to run on 30% max Nitro (unblown) using 12 1/4 to 1 Compression which is as far as I feel is safe for 30% (okay, what the hell, lets make it 35%)!
Basicly, I used a Dart Big M tall deck block with billet main caps, ARP main studs, Callies Crank, Carrillo rods ($2200 a set), . . .
Buddy, you've got 40% fewer main bearings than Bob, and you want to run Blown on Nitro? :?
I understand that Colorado just legalized pot, but DUDE, you don't have to advertise it . . .
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This seems like something to learn about on an inline four cylinder that is easier to work on and has a lot fewer parts to buy and modify.
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I know the MG factory team of 1957 was running 86% methanol with nitrobenzene, acetone and sulphuric ether in the EX 181. That was a four banger with dual overhead cams and 3 mains, supercharged, 90 CI and they got 290 hp out of it. They buzzed it up to better than 7 grand, but there was a whole lot less reciprocating mass, and a lot less car to push down the salt. And it certainly didn’t hurt that they had a fistful of factory engineers on the project, along with a deep reserve of cash.
I guess I shouldn’t be so mean, but there’s still so much that you still question about this combination that to jump into Funny Car Fuel is a step farther than seems prudent. I agree with Stay'tee – inch your way up on this one, and monitor everything.
I’m going to be there this August – Freud and I will be the ones with the prayer beads.
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I'm afraid I have to echo what others are saying about nitro being too big a "leap" at this point.
To add yet another viewpoint to all the others: why not develop a comfort level of burning methanol, then up the boost as needed for your goal? Simply switching to one of the modern twin-screw blowers offers huge gains in blower efficiency.
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Just a few basic parameters: I built my 496 Dart BBC to run on 30% max Nitro (unblown) using 12 1/4 to 1 Compression which is as far as I feel is safe for 30% (okay, what the hell, lets make it 35%)!
Basicly, I used a Dart Big M tall deck block with billet main caps, ARP main studs, Callies Crank, Carrillo rods ($2200 a set), . . .
Buddy, you've got 40% fewer main bearings than Bob, and you want to run Blown on Nitro? :?
I understand that Colorado just legalized pot, but DUDE, you don't have to advertise it . . .
SHHHHH! They're watching....... lol!
Interesting responses, er...warnings! Lol!
Out of curiosity, how many of you have actually run nitro? I mean no disrespect, I'm just curious.
Here's my biased, and probably warped view on it. I don't think the engine knows if the extra cylinder pressure comes from added boost, or nitro- cylinder pressure is cylinder pressure! I believe the only way I can achieve my goals is with added HP, and alcohol alone won't get me there.
Of course, as pointed out, the engine may not survive. I'd rather give my everything to achieve this goal, than look back at a failure, and wonder if I could have somehow been successful, if only I had....
So, please help me make this engine survive, using this volatile stuff- feed me some useful info to keep me from unnecessarily grenading the engine!
Just a few basic parameters: I built my 496 Dart BBC to run on 30% max Nitro (unblown) using 12 1/4 to 1 Compression which is as far as I feel is safe for 30% (okay, what the hell, lets make it 35%)!
Basicly, I used a Dart Big M tall deck block with billet main caps, ARP main studs, Callies Crank, Carrillo rods ($2200 a set), JE pistons, Barnes six stage Dry Sump oil pump, external JK water pump, Donavan Gear Drive, front driven Mallory Mag IV, Comp Cams Cam and Roller Lifters, Jessel shaft rockers and 7/16" pushrods on Dart Heads, using ARP head studs, Cometic Head Gaskets (MLS), and NO O-Rings head to deck. I use a Edelbrock tunnel ram with a Enderle hat and a front drive Enderle pump.
Now add up the cost of those parts and keep in mind that every four runs I get to remove the $700. pan to replace the rod bearings and now you are in the ballpark........
NOT INCLUDING THE BLOWER which you better be ready to restrip every four or so passes.
Add in a new blower belt every few runs, and don't forget that the oil in the engine (I run eight gallons) must be changed every pass because of dillution.
Now if you have the ball's to fire it up, try to remember to back the motor down first or your new blower and hat will be in your neghbors yard or living room, and you will never hear clearly again.
Oh, once it fires, you are doomed................. nothing (except maybe Beer and Sex) will ever be of interest to you except....................... NITROOOOOOOOOOOOOOO!
One Run Bob (maybe 32% should be where I stop) :roll:
Bob, Interestingly enough, I run many of the same parts as you- billet main caps and girdle, ARP main studs, Crower crank, Crower rods ($2200 set), Venolia pistons, Barnes dry sump, external water pump, Donavan gear drive, front driven mag, Elgin cams cam and custom roller lifters, ARP head studs, and new Cometic head gaskets. The Elgin cam, rollers, and Cometic head gaskets are new this year. I also run a 6-71 stripped blower, with Enderle bugcatcher and front drive Hilborn pump.
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I read sometime ago that to double the horsepower N/A you increase the stress by 350% + or - 50% to double the HP with turbos it only adds about 20% more stress on components. Buddy I would sure look at Blow through Carbs, Turbos, Intercoolers, and Methonol---much higher knowledge base--- much more forgiving --- the alky broadens your tuning window and is much more forgiving!
IF you were to CHOOSE to TRY do it on race gas --- all you have to do is break the seal or run 70-30 with you water injectors to be in the fuel class.
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The amount of blown nitro grenaded motors can be weighed in the tons. Only because it's easier to do then on gas. But grenaded blown gas motors are out there too.
There is no end to the amount of horsepower you can create. Think 90 psi, 80 percent nitro AND nitrous!
The limitation is all in the metal components. Somewhere between running 100% methanol and the explosion is an answer.
If you think you have a target horsepower number then start with 10% on the dyno and tune for that. The result will point you in the right direction.
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The people I would talk to is John Beck and Fred Dannenfelzer. They know how to make them live. My experience is 75% unblown and with that knowledge I can say a few things:
#1. Get a bigger gear and tire. Nitro makes a ton of torque, burns slower, and doesn't need RPM to do the work. That blown Caddie should do everything you need under 5000 (probably 4500)
#2. Don't let it unload. Learn to drive with that egg under your shoe. If you do get out of it go back in slow.
#3. Your car will never smell that good again............Good Luck :cheers:
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I've run a couple of small blocks on the dyno with nitro. A "C" motor with 10% N/A picks up about 75 hp. No muss or fuss, kinda easy or no big deal. 12.5:1, no timing change, didn't delute the oil right away. Just a simple way to get 75 ponies.
The problem comes when you start pushing. After about 25% the details to keep making more power started to take the "fun" out of it. And as I'm sure you know or at least have heard it said.......... "we need just a bit more, lets tip the can".
Buddy, I know you have a big car, and it sure ain't very aero........ But 850 hp for 200?
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Just to add to my previous post, when I stated that I built the motor for Nitro, it has to this date only made one pass (with 25%) burning Nitro and was shut off at the 4 mile at 225 mph.
We have spent the last three years running straight Methanol trying to see how close we can get to the 250.5 class record (A/CFALT) on Alky alone before we start back on the Nitro program. This is the only way I can afford (like hell!) to learn what the motor likes.
So far we have gone 238+ which isn't too bad for a 12 to l motor (Alky likes 14 to l or higher) but I specificaly built this motor for the low dosage of Nitro (for my own sexual gratification)!
When I (hopefully) restart the Nitro effort it will be on 20% and then gradually build back up 5% at a time.
Nitro takes no hostages, you either treat it with respect or it will bite you right in the wallet....................................... One Run, out.....................
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Buddy..just estimating on these numbers with the Bville pro computer program
30 sq ft frontal area
.4 CD
3300 lbs
510 hp =167 mph
856 hp =200.7 mph
Takes a bunch of hp to push a brick.
If I knew your frontal area-weight and speed at Bville, Bville pro could calculate the CD and HP.
JL222
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Thanks JD, Bob, and Dean! That's good info! John Beck will do our tune on the dyno.
Yea Mike, it takes a lot of HP to push this brick!
John, Thanks! Frontal area is about 29 sq.ft, weight was 4400lbs, and speed was 166 mph. You were as close as you can get!
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Out of curiosity, how many of you have actually run nitro? I mean no disrespect, I'm just curious.
I helped a guy back in 1969 and 1970 run a Jr. Fuel car, so I will not be any help. We ran 85-90% at the time, and the one thing I do remember is running rich was way easier on the parts in the motor.
Here's my biased, and probably warped view on it. I don't think the engine knows if the extra cylinder pressure comes from added boost, or nitro- cylinder pressure is cylinder pressure! I believe the only way I can achieve my goals is with added HP, and alcohol alone won't get me there.
Why not alcohol and added Boost? Just curious. Another question. Is there a reason why this goal of 200 has to be met in 2013 ? Sorry I am not any help, but as I said in my previous post I wish you the best.
Tom G.
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Out of curiosity, how many of you have actually run nitro? I mean no disrespect, I'm just curious.
I helped a guy back in 1969 and 1970 run a Jr. Fuel car, so I will not be any help. We ran 85-90% at the time, and the one thing I do remember is running rich was way easier on the parts in the motor.
Here's my biased, and probably warped view on it. I don't think the engine knows if the extra cylinder pressure comes from added boost, or nitro- cylinder pressure is cylinder pressure! I believe the only way I can achieve my goals is with added HP, and alcohol alone won't get me there.
Why not alcohol and added Boost? Just curious. Another question. Is there a reason why this goal of 200 has to be met in 2013 ? Sorry I am not any help, but as I said in my previous post I wish you the best.
Tom G.
Tom, we will try alky and more boost on the dyno, but do you think that will be any different than nitro, in the fact that both ways I have more cylinder pressure? I do realize it would be a LOT easier to tune, if it will build the needed HP.
As for does it need to be this year- I wanted to take 2013 off, and get the engine ready for a special construction car- turbos, EFI,different intercooler, etc.. In fact, Sparky lent me most of the stuff for the conversion!
At the end of B'ville last year, I told the team this, and they weren't happy, so we held a team vote- I was the only vote for jumping right to special construction. Since everyone on the team does soooo much to make it possible for us to do this, I respect their collective opinion.
So, this year is for me to see just what the engine can really handle. 200 mph seemed a worthwhile goal to push the engine, and it's a one shot deal.
Ultimately, I want to follow in Jimmy Stevens and Ron Main's footsteps, and push over 300 mph. This engine with turbos and fuel will already make as much or more HP as Main did, but for how long I don't know. I also figure I'll need more HP than he did, because finding and fitting it in a car like the Speed Demon probably won't happen!
I know it sounds a lot easier than it will be, but I have time!
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i ran a injected blown fuel bike (970cc Z based Kawasaki, Hilborne in frount of a 60c" Magnusson) back in the earlie 80`s, this was the begining of my nitro experience, but a divorce soon put a stop to that, :lol:,,, over the last cuppla years i have been messing with the stuff in my inline n/a four (Kawasaki ZX12) and have seen a real gain at the wheel on the dyno and out on course at 20*,,
ive had zip experience with flathead chamber design, but have found that what works in a hemi head dose not necessarly work in a pent roof,,
keep a "real close" eye on A/F, every percentage change, along with temperature (both fuel and ambient) will "affect" A/F, the jimmy`s going to complicate this, but moniter "everything" and err to rich, 8-),,
imho the biggest problem with "juice" is the naysayers, the WOW factor based on nothing else than seeing what it dose when people do not have a clue,, :evil:,, if more folks started ignoreing this and had a go at small doses the information shared would be priceless, not to mention performance gained,, :cheers:
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Freud's post#3921 ranks number ONE for wit and wisdom! Some where in my extensive hot rod book collection is an issue with one of the first articles on running NITRO. It got into all aspects of what was known about the stuff at the time. Technical type stuff. How to modify your Stromburg 97 and the like. One of the pictures used was a pile of Ford V8 flatheads that had given there all at Bonneville. If I can find the book and send you the picture you'll be able to superimpose your engine in the picture and make a cool T shirt to sell and try and recoup some of your losses. No thanks to Freud, I'm going to go and change my undies.
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I myself would love to build a nitro-burner but can't afford it. I say go for it :evil:. Going lean is when things go boom, and you need a healthy fuel system to keep LOTS of nitro packed in the cylinders. Here is some inspiration!
http://www.youtube.com/watch?v=WLFTO0Bx9-E
http://www.youtube.com/watch?v=NfQUc5F_JMs
http://www.youtube.com/watch?v=5dfTktM4JzI
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Gasoline runs at 14.7:1. Very stable, well known properties.
Methanol runs at 6.4:1. Also very stable, and you do need twice as much.
Nitromethane at 1.7:1 requires massive amounts of fuel compared to gasoline. Trying to pour that amount through a carburetor is a tough deal. Injection is the only way to go.
So yeah, it makes a bunch of heat and pressure. It's much harder to reach the mechanical limits with gas or alky. Not so hard with dial-a-percentage nitro. Tipping the can is so gratifying! And the smell is sooooooo good. I love the smell of nitromethane in the morning. :cheers:
These days with sensors and data logging and dyno runs you have a much better handle on what the engine is telling you. Having a good dyno baseline will save you parts on the salt.
both ways I have more cylinder pressure?
True enough. Cranking boost allows you to stuff more fuel in, gas, alky or nitro. The only question you can't answer, and really don't want to answer, is what is going to break first.
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This might help. It is experience from the 1970's when we were trying to build British vertical twins capable of racing against Japanese four cylinder bikes. The weaknesses of the brit bikes were poor machining for the most part, weak metal, and designs that were originally done before World War II. The engines were naturally aspirated and running on gas. The failures were like engines using fuel, i.e. cylinders pulling away from the blocks, cylinders breaking at the base flanges, rod big end bearings flattening, etc.
This is what I learned. The combustion process produces a peak pressure a short time after ignition and this is not proportional to rpm. The pressure spike, if it happens when the piston is too close to top dead center, pushes down on the piston when the rod has poor leverage on the crank. This is hard on the rod bearings, everything else, and it hurts power. The pressure spike itself, if it happens when the piston is too far down from TDC, is not as great as it can be - although the rod to crank leverage is better. The pressure spike and piston position need to be optimal for the most power and engine life. Spark advance timing can be used to keep the pressure spike and piston position optimal, to some extent. So can choice of fuel. The other factor is engine speed. The piston is further past TDC when the pressure spike occurs at higher rpm.
One of my engines was built at the limit in regards to compression and the anti-knock capabilities of the gasoline I had. The pressure spike and optimal piston position were within tolerable limits for a few thousand rpm. My method was to roll on the throttle until the engine was within those rpm limits and then to open it up all of the way. That is the only way I could get the engine to be powerful and reliable.
This is a long story. The point is, it helps me a lot to be aware of what happens in the combustion cycle and when it occurs. Some of this might apply to fuel use.
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Buddy --
Maybe changing your frontal area would be less expensive in the long run than going to nitro. How about a 48 Crosley? Here's my one voyage into nitro, be it 50 years ago. We didn't use much and surely didn't learn much.
Gee -- this car might be just right for the new Roadster class!
Stan
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Buddy --
Maybe changing your frontal area would be less expensive in the long run than going to nitro. How about a 48 Crosley? Here's my one voyage into nitro, be it 50 years ago. We didn't use much and surely didn't learn much.
Gee -- this car might be just right for the new Roadster class!
Stan
Does the tree come with it? :-D
Are those portawall white sidewalls on those slicks? We had them on our drag street roadster in the late 50ts :roll: They would come off at high speed [for then].
JL222
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Gasoline runs at 14.7:1. Very stable, well known properties.
Methanol runs at 6.4:1. Also very stable, and you do need twice as much.
Nitromethane at 1.7:1 requires massive amounts of fuel compared to gasoline. Trying to pour that amount through a carburetor is a tough deal. Injection is the only way to go.
figures quoted are for "raw" fuel,, the actual A/F depends on the percentage you are going to mix, then take into account the variables, temp, boost etc, it aint easy but do the calculations, will save, or at best minimise brakeages,, :-)
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Buddy,
My comment regarding running enough "pop" (nitro) to go from 570 to 800 hp is that I think you could convert to alcohol, increase your blower pressure and probably get very close to or exceed 800 without the risk of nitro. The great thing about alcohol is its' latent heat, i.e. its' ability to adsorb heat out of the incoming air and reduce the charge temp and therefore increase the air density. Properly done a good alcohol system can take 100 degrees out of the inlet air temp which of course means you can run more boost. When Indy cars were running turbos with unlimited boost the 159 inch Offies were making around 1200 hp on about 100-120 inches of boost, without an intercooler and they could run like this for 10 miles to qualify. You could even add a small shot of nitrous if you needed a quick 50 hp to make 200, and there are a lot of guys on this forum that have nitrous experience.
A comment about nitro: Nitro is very close to being an explosive and can be dangerous. A friend of mine, who runs a D fuel lakester, runs a 300 inch Chrysler on 90% and after a run several years ago he pulled back into the pits and did not realize that there was a fuel leak in the return system that allowed fuel, 90%!, to leak back into the engine. While sitting in the pits, right after the run, he accidentally hit the ignition switch which caused a spark in one of the front cylinders which set off the nitro. It did not crack the block or head it blew them off!! the complete front of the block and head on one side was completely blown away!!! Not something I would like to work with.
Rex
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This is more about what I learned with the British bike fiasco. Ignition timing in those days was by mechanical systems with counterweights and springs. The typical setup in those days was to have the spark at full advance at about midway between idle and red line. The advance curves I set were as linear as I could make them with full advance occurring at red line, and not before. This was done after figuring out the relationships between combustion speed, rpm, and piston position. I did this by putting heavy springs on the advance and lightening the weights.
Once the advance curve was set, I set the ignition to a setting I knew would be retarded. Then I went out to a back road where I could do some testing. I made runs and looked at the spark plugs. The positive electrodes were what I examined. I advanced the timing gradually until the outer 1/4 to 1/3 of the electrode length was shiny. Then I had the timing set. I put a timing light on the bike and made timing marks on the rotor so I would have a reference when I set the timing in the future.
In those days I was barely older than the teens. I did not know jack rabbit on my own. I could listen and take advice and the folks that helped me were familiar with fuel. This is NA gasoline experience. It might help.
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Thanks Guys! Lots of good info here!
I guess we'll see how much HP we make on fuel, then decide which way to go.
Rex, I've blown a couple of engine up on nitrous, mostly because I got greedy! Still, it might be a better alternative than nitro.
Are guys using it the whole run, or just fogging it the last 1/2 mile or so? Simple push button fogger, or controlled electronically?
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Jason...Your avitar has a bike so that may be your thing but I saw no difference in building a fuel engine versus gasoline and we used 75% as a goal. One time we started at Bonneville too lean and hurt some valves but that was it. Same expensive pistons, rods, valves, cam, steel main caps, etc. Yes the barrel of nitro costs $850 at the time and when we reched the limit of RPM (yes there was one) taller tires were bought twice but that had nothing to do with the engine.
Every year the engine was torn down, valves were checked, rings changed and bearings inspected. Maybe we were lucky in a way because we needed only 2 or 3 passes to bump up a record and we changed oil after every 2 runs. (unblown) but in reality I do the same with my gas engines with the execption of the oil. Winter is tear down. If you want to run at the top of your class this is all a necessity. Your competition is doing it to catch and pass you. Good Luck
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jimmy, bikes are actually new to me. I've always liked them but my wife finally changed her mind about being scared of me owning one and decided it's something we could do together. I'm still first and foremost a car guy, although if it has an engine, I'm probably going to like it.
I know the cost for a competitive race engine will be pretty much the same, just different specs (compression ratio, cam grind, etc.), I just don't have the money for either lol. You would be hard pressed to find someone who loves flatheads more than I do, but unfortunately I don't have any experience building them. I would LOVE to build a Vintage Fuel Competition Coupe out of a '33 Ford Sedan or a Fuel Modified Roadster, but I don't see it happening in the near future.
I'm glad to hear you didn't have any major problems with nitro, and I wish you the best of luck.
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My experience with nitro was with my unblown BBC dragster . 300 runs including getting the NHRA et record in 1968 . It was fairly easy on parts . 75% normally . Stock head gaskets and rods with small 3/8" bolts . Checked the bearings every week and never lost one . Singed one piston when a splinter partly blocked a nozzle. It made power with lots of spark and as much compression as possible . 12.8:1 was all you could get with a .060 over 427 . The only oil then with additives to prevent piston scuffing was 70 wt Penzoil . Probably not a proplem with lower % . Saw a friend's jr fueler make one of his best runs on 28% . One of the things I wished I'd tried was low % . With an unblown engine on high % it's very difficult to get the nitro to release much of it's oxygen . The only way I found was nough CR and spark lead to make it detonate which tuliped valves and ocasionally broke ring lands . Gene Adams did it far better by getting pistons with thick crowns and warming them well while staging . Tom Skinner ran a low % in his GMC's to stay competitive with the 480 ci BBC modifieds . Nitro is beautiful stuff , especially with small % . The stories of damaged engines and burned pistons I think come from running lean on high % . As I said my only nitro experience is with drag racing but I wouldn't be afraid of 10% or 15% with LSR with proper jetting .
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Thanks guys- good info here!
I talked to John Beck today, and we'll dyno and tune on gas.
We'll then change ignition, add a computer system and MSD box, and tune on alky. John feels nitro is more stable than nitrous, so if we still need more HP, and haven't used the kitty litter yet, we'll start adding the pop. John doesn't think we'll need much-10-20% max.
It would be real nice to have a good 'tuner' on the crew for B'ville! :-D
Happy new year!
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"nitro is more stable than nitrous", x2, :-)
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I tried adding 15% nitro to my Ford flathead at WOS on my backup run. I only ran a little over a mile an hour over the record for my class the previous day and it was 46 degrees so it seemed like a good idea at the time to add some nitro.
I melted 3 of the outside pistons (1,5, & 8) however the motor sounded like it was on steroids. Aftrward someone came to our trailer and asked if it was really a flathead (I run a 4th exhaust out the heat riser hole) because it sure didn't sound like one.
I'm running 21 pounds of boost and a 2 port Hilborn with direct port injection. I ran the same size nozzles to all cylinders.
Ross has made me some heaver pistons and I plan to run larger nozzles to the outside pistons for 2013.
Just a little info from someone who has some experience blowing up flatheads but I think I'm getting close.
Happy 2013!
Jerry Wortman
#7472
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Thanks everyone!
I just got off of the phone with Rick Schnell, owner of 'Slider", the worlds fastest flathead dragster, with over 900HP.
Interestingly,he too only has 3 mains, Moldex crank, Crower rods, big crank girdle. He's running 60% nitro. He said sneak into the tune, and don't get gready. He says for every 10% nitro increase, he has to fatten the fuel return by .010. He says go .020-.030 to be safe.
Boys, if we don't go lean, I have to think we have a shot!
Forgot to mention, though, the block is aluminum filled.
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Also only run a 1/4 mile at a time. :-o
Have fun with the project! 8-)
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38,
what do you mean by fattening the fuel return by .1 ?
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38,
what do you mean by fattening the fuel return by .1 ?
Haha! I meant by .010! I corrected it. So, you would decrease the return pill by that much.
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having a hard time posting on 3g for some reason.
after thinking more, it seems like it was for fuel injection and pill size.
another subject I'm not well versed in.
better to find out now about the difference in the sizes than with a running engine.
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Nitro air/fuel is odd . Lean is bad , a little rich is good , very rich is very bad (at least for unblown) and very very rich is where the big power is . Very very rich is where modern top fuelers , the unblown nitro TAD dragsters and the Davidson roadster are . With very rich being so bad no wonder it took a while for very very rich to be discovered .
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IIRC, the temps and pressure at full scream will cause nitromethane to burn without free oxygen if it's super rich and has consumed all the air. That's where the hydrogen comes from that burns out of the zoomies, burning nitro with no air makes free hydrogen gas, which would normally become water if there were more air. So the hydrogen burns AFTER it leaves the pipe. Flame temp goes down, but cyl pressure goes up. All molecules take up about the same room when they are a gas (liquids don't burn), so when H2O is made, the temp goes up, but volume goes down.
Or I might have misunderstood what I was told. I know nothing about it other than it's expensive, won't mix with diesel, and will dissolve super-glue.
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Sidebar: Turbocharging is the best form of supercharging when there is head flow limitations. The exhaust gases are always compressed, so sound waves move faster, and port size isn't as much a handicap. Methanol + high boost turbocharging can go >10HP/CI. Pretty sure your hard parts won't hold what a max effort turbo/meth setup will hit.
Nitro with a roots blower will certainly make huge power, but might not be the cost effective solution for any given HP level.
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Sidebar: Turbocharging is the best form of supercharging when there is head flow limitations. The exhaust gases are always compressed, so sound waves move faster, and port size isn't as much a handicap. Methanol + high boost turbocharging can go >10HP/CI. Pretty sure your hard parts won't hold what a max effort turbo/meth setup will hit.
Nitro with a roots blower will certainly make huge power, but might not be the cost effective solution for any given HP level.
I totally agree with you, and that is the plan once we are able to move to special construction.
As long as we continue to run a vintage class, though, we can't run a turbo.
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Sidebar: Turbocharging is the best form of supercharging when there is head flow limitations. The exhaust gases are always compressed, so sound waves move faster, and port size isn't as much a handicap. Methanol + high boost turbocharging can go >10HP/CI. Pretty sure your hard parts won't hold what a max effort turbo/meth setup will hit.
Nitro with a roots blower will certainly make huge power, but might not be the cost effective solution for any given HP level.
I totally agree with you, and that is the plan once we are able to move to special construction.
As long as we continue to run a vintage class, though, we can't run a turbo.
Odd since turbocharging started in 1905. But rules are rules.
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Just how fast is the World's Fastest?
Ex-Coltonite wants to know.
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At Bandimere's,5800' above sea level, just outside of Denver, he ran a 8.24 @ 167.75 MPH
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Sidebar: Turbocharging is the best form of supercharging when there is head flow limitations.
Nevertheless, an obstruction is still an obstruction, regardless if the engine is under boost or not. Unnecessary boost, be it from a blower or a turbo, restricted by the flow of the intake port and head design, requires more power to fill the intake, and produces more heat doing so. Additionally, seeing as both the intake and the exhaust ports are on the same side, additional heat is being transferred to the charge from the adjacent ports.
Buddy, I seem to recall a rework on the head was under consideration when you were doing the flow numbers and dye tests. Did I miss a post? I know it's an arduous path the charge is taking on this engine, but the more you can free up the flow, the less artificial atmosphere you'll need to make power.
This engine scares the hell out of me - that's why I love it . . . :cheers:
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Chris, we are making the mod to the chambers, that the flow bench showed improved flow. In addition, the chamber is being set .12" 'deeper' into the head, so that we have the proper clearance with the Cometic gaskets.
The engine doesn't scare me, but having to use mass amounts of kitty litter does! :?
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... he ran a 8.24 @ 167.75 MPH...
That's way short of putting the major fraction of 900 HP to the track. Just sayin'...