Landracing Forum
Tech Information => Technical Discussion => Topic started by: racer x on July 19, 2008, 11:44:05 PM
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I was wondering . For you people running nitrous on a motorcycle . How much do you use in general? I mean if you have a 2.5 lb bottle . Do you refill or top it up between runs or make 5 runs on one bottle? Thanks for your help
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Racer X
Depends on your bike and class, some bikes run out of Nitrous and have had to resort to a larger bottle and diifferent tune up and some have found the better bottle is made by Garrett :mrgreen:
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Thank you . Congratulations on you latest records Mr Noonan.
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Thank you . Congratulations on you latest records Mr Noonan.
R/X,
I drag raced with N20 for a season or two and found Bottle pressure was THE Key!As it would run Pig Rich when the Pressure dropped 50% by the end of the run.We Went to 2 -2.5lb Bottles for a 100 shot for 1/4 of a Mile.Then Would Top off each bottle after every pass.
Like The Worlds Fastest said Garret market a Nonrefillable unit :evil:!
Kaz.......
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Search the topic, it has been discussed a lot. If you are planning to go fast, get a 10 lb bottle, use 8-9 lbs of it every run... :wink:
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Depends on size of your shot and how many gears are you going to spray in. But volume is good,double up your bottles.
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Don't laugh. I am tinkering with a 10 hp "shot on a 250 cc four stroke. they have 10 oz bottles but even for the small amount I need . if it goes rich becausee the pressure drops then it looses power.2.5 lb bottles looks like a scooba tank on my little bike .But as I said Im still tinkering.I would only spray in sixth gear .I was just woundering how much the big bikes went through on a one mile track like Maxton
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I am moving forward with my 15 cubic inch nitrous bike.
I have spent three seasons tweaking the bike. I went from my 87 mph first pass in 2008 to 109.7 fighting a slight wind in April 2010. Now I can add power with out waisting much.
The bike will go 14 sec in 1/4 mile@ 91 mph in forth gear.I go 110 in a mile. I am in 6th gear for 1/2 mile and intend to start spraying at the 3/4 mile marker. About 7 seconds of spray
First thing I want to do is figure out a system that is appropriate for a 1 mile ECTA bike. It is a 250 cc Four stroke engine that made 26 hp@11250 and now makes almost 34 at over 12500 rpm.
The engine likes timing .The more I advance the timing the more fuel it burns and the more power it seems to make
I am using s stock engine But changed from 11.6 to 1 stock cast pistons to 12.5 to 1 JE pistons. That and carbs and timing have made the power.
For nitrous I have a thick copper head gasket.I can raise the head up to reduce compression.( I can adjust the cams to compensate for raising the head) .The JE pistons are forged
Plan 1 was to use a dry shot .The bike runs a 118 jets .So I figure a 123 jet and advanced timing.Then using a Mini NOS controller I would reduced the timing advance from 45 deg to 35 deg and spray Just nitrous .And see what happens.
Plan 2 was to use a wet shot . 1000 psi in the 2.5 lb bottle and a 7.5 lb of fuel pressure with jetting that is yet to be determined .And using the same scheme spray both fuel and nitrous .Without a Controller.
My question is what Octane fuel should I use ?
should I use one octane for the carbs then use higher octane from a separate tank to feed with nitrous?
And what jet size are there.One thing I read says 15 nitrous and 18 fuel will make 10 hp .Another says .38mm nitrous and .40mm fuel.
What is the common measuring unit ?
I have not even gotten to the bottle filling part. Can I just put a big 20# bottle in my van and fill up 2.5 lb bottles at the track ?
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Yes you can fill at the track, big bottle in the sun, little bottle in the cooler, baby scale to ensure you don't put 4 lbs in your 2.5, but you probably can put 3 as long as you keep it cool, in the 800 to 850 range. When you start spraying the bottle will get cold and drop to that pressure anyway.
Again I will warn you to know what you are putting in your motor. Waste a pound or two and learn what your ratios will be. Weigh your gas for the same time period.
Unless you are injected and have a way to control enrichment don't try a dry shot...
Or you can break out the torch and see if it will cut a hole in your head and pistons..... if it won't you will be OK with in motor experimentation.... :roll:
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The amount that you are spraying with a 250 only in high gear is pretty minimal. Start easy and work up.
I would suggest that you work out the bugs on a dyno before you head to the track.
If that's not in your budget . . .
Gas = 34 hp
Very small amount of N2O = More hp
Very small increase N2O = Maybe more hp, maybe hole in piston
Very small increase again N2O = Maybe more hp, maybe hole in piston, maybe rods hanging out the bottom.
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Just curious..what exactly are you using to change the timing on your 250?
Thanks.
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I have special ignition system made in Thailand.Called a BRT-Tis .It has a programmable rev limit to 16000 rpm and fully adjustable timing across 30 programmable steps. I change about 1/2 a deg every 500 rpm but that is totally variable. It also has a two map memory to so I can change maps from a push button switch on the bar or through a relay controlled by a nitrous controller like a mini NOS.
The problem is And I spend months on the phone with MSD and Dave Daugren at EMS.The 250 ninja pickups don't talk to any regular ignition units . Something about the pulse width. The only solution was to make something $$$$$ or run universal pick ups and no charging system .Or mount a pick up through the cam cover. None of those solution cost 300 dollars and works perfectly like the BRT-Tis.So I was very happy when I found it.I also adapted an 88-94 ignition system that raised my limit and advanced the ignition but was not adjustable.
As for testing. I use a duyo for all my testing. Then the 1/4 mile track.And once everything is ready I go for the mile.
The plan is to build the system off the bike and (like you said) Fire the system and measure two things.How much dose the weight of the bottle change with 10sec of activation.
And how much pressure will the bottle have after 10 sec of activation.
Once I get it on the bike I will go to the dyno.
There I will be looking for Power increase and A/F ratio.
Going with a dry shot is NOT what I want to do.But it is not out of the question . The engine runs with very good power at 12to1 then as I add timing it makes great power and goes to close 15 to 1 .If I take away the timing and given enough octane it may work.
Blowing a hole in a piston is one reason I got away from the thin crown cast pistons the bike came with .(Edited)
Now that the war in Bangkok is over They will ship my belly pan . So I will have a oil catch and oil absorbent mats in the pan.
I also have the rods from carrillo :wink:
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Dose anyone run one octane for motor than a different octane for the injection? Or is that a drifter car tuner thing
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i don't know who is tuning your bike but i guarantee your motor wont make it to the 3 mile at 17to1 air fuel.... is this an air cooled motor? how many nozzles are ya planning on running?....
Kent
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toooo much sun today. 12 not 17 . The bike runs well rich. Then as I add timing the mixture leans out. If I where to run rich then retard the timing and spray just nitrous .It MAY work But I am not trying a dry shot.
It is a water cooled engine and I am planning on one fuel and one nitrous nozzel per cylinder. There are two cylinders.
I only need to go 1 mile . BUT not at 17.to 1 :oops:
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I run between a 140 - 200 hp jetting for 1 mile and can get 2 runs from a 5LB bottle
Guy
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I run between a 140 - 200 hp jetting for 1 mile and can get 2 runs from a 5LB bottle
Guy
If that is a four cylinder motor. with 4 nitrous jets and 4 fuel jets.
If I want to run a 2 cylinder bike with 2 fuel jets and 2 nitrous jets making 14 to 20 hp .Then I would use 1/10th your total volume ? Is it that simple?
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racer x......they are ALL variable cylinder, variable displacement engines.......
...using variable amts of nitrous....depending on the day...run..etc..
nitrous.......invariably variable.....
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I found the Dyno Tune web site. It had lots of info and Kits They also have a jet calculator.
I entered 7.5 lb of fuel PSI and 1100 psi of nitrous pressure. For 15 hp it said 16 and 18 jets. BUT that is ONE jet and that is a fogger system.\
http://www.dynotunenitrous.com/store/Scripts/Jet_calculator/nitrousjetcalc.asp
Do I then divide that number in half and use 8/9 jets? I know it is just a starting point.
http://www.dynotunenitrous.com/store/scripts/prodView.asp?idproduct=174
They sell a KIT for a 2 cylinder engine . I don't think I can get those nozzles to fit. I can use the 90deg style but That will be a tight fit.
http://www.dynotunenitrous.com/store/scripts/prodView.asp?idproduct=250
that KIT says 18 hp jetting comes with it.Should I buy that and just got one step smaller with the jet size?
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You would have to custom make jets if you want to go much small than a #16 I think.
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That is what I mean when I say I am in uncharted territory.
How about lower bottle pressure?
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Try contacting the BuddFab Streamliner guys...they have experience spraying small engines.
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These replies are being very helpful to me as well and I am feeling more comfortable about nitrous reading this, I just tried the calculator racerx posted and trying different imputs sheds a little more light on things.
Thanks for what has been posted and please contribute more if something important is lacking, Jon, thank you for the website.
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This is all a learning experience and it will be fun to see it go.
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I found the Dyno Tune web site. It had lots of info and Kits They also have a jet calculator.
I entered 7.5 lb of fuel PSI and 1100 psi of nitrous pressure. For 15 hp it said 16 and 18 jets. BUT that is ONE jet and that is a fogger system.\
http://www.dynotunenitrous.com/store/Scripts/Jet_calculator/nitrousjetcalc.asp
Do I then divide that number in half and use 8/9 jets? I know it is just a starting point.
http://www.dynotunenitrous.com/store/scripts/prodView.asp?idproduct=174
They sell a KIT for a 2 cylinder engine . I don't think I can get those nozzles to fit. I can use the 90deg style but That will be a tight fit.
http://www.dynotunenitrous.com/store/scripts/prodView.asp?idproduct=250
that KIT says 18 hp jetting comes with it.Should I buy that and just got one step smaller with the jet size?
RX, using the calculator just figure half the desired HP if you are planning a 2 cylinder, 1/4 for a 4.....
If they have jets in a 10 HP kit buy 2....
As suggested you may need to buy jets, solder them closed and drill holes... Flow the learn pounds of fuel to pounds of N20 and you are set. The calc should give you good starting drill sizes.
Again good luck.... With N20 it is better to have a lot of luck and a little skill :-D
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Thanks
The Kit I posted comes with 18 or 34 hp jets. 18 is my magic number .I need about 50 hp to get a" D "licence @ 125 mph. I have lots of experience reaming jets because I work in a scooter shop. Personally I hate to do it .I don't feel it is very precise. I always try to use new jets .But some times it is quicker to make a 50 dollar scooter run .
I developed a way to measure the hole and depth of the throat part of the jet.
So my plan is to buy the kit and solder the 34 hp jets closed then measure the 18 hp jets . Then I will need to figure out Half the flow rate.
I do know half the hole size is not half the flow rate.
I will put the system together OFF the bike. and spray nitrous for 10 seconds . Then measuring bottle weight I will make my best guess till I spray half as much as an 18 hp shot will require.
That should be a 9 hp shot and a good starting point.
Dose this sound logical?
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Eric,
Yes it sounds logical... but be careful,, as logic many times does not previal with power adders.
Back in the early 80's when I was drag racing Suzuki's (not much info and parts available for N2O back then)
We used logic in place of experiance with N2O.. and lost 2 engines in two weeks.. I have not tried N2O since..
Have fun, good luck and do what you are doing here,,, asking the folks that DO have many years experiance with N20...
Our knick name for N20 back them was Ka-boom juice...
Charles
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"If you spray - you'll pay!" Or -- "If you're spraying -- soon you'll be paying."
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Speed cost money. :lol: I just have to spend it in the right places. That is why I have spent so long tweaking the bike on the stock motor.
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Eric, I feel confident 125 is in your future with the lil 250.
Keep the faith....
Charles
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why are you trying to screw with your jets? let me ask ya this..... why do ya think an 80hp shot for a 4 cylinder 4 nozzle kit is the smallest kit most of the NOS manufacturers sell?.... Ya think they have had, or know of problems with running a smaller jet? like freezing or plugging? smallest flare jet ive seen is .010 and funnel jet at .008.... NOS is tricky enough..... just put in the 18hp shot and run it....
kent
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Kent Ya think you were clear enough :?
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Racer X - just so you know NX makes jets .009, .010, .012, .014, .015, .016 - they use the tiny one's in RC cars
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Nitrous is something I have not used, but I have done other similar goofy stuff. One thing I learned is to take plug chops during the first runs and to look at the plug with a magnifying glass. Look for any molten aluminum flecks. Look down through the plug hole at the piston crown. The carbon coating should be light tan to nipple brown. Bare metal or pitting on the crown is an indication that it is time to do something different.
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with nos you don't get a chance to do plug chops and look see how every things gettin along within your motor...... its usually everything is tuned up and fine then blaaaaaaaa as it melts your piston and head or BANG as it tosses a leg out the cases.....your tune up can be good 1 day and junk the next...... 2 things are for sure with NOS, everyone gets greedy and you will blow something up...
Kent
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Thank you all for the responses.
I understand you logic with freezing jets. and getting carried away with unrealistic expectations.Greed dose not play into it though
I have very specific goals and expectations.
I am not building a Hyabusa.it is a 3500 dollar started bike with a fragile 249cc engine.
I will eventually need to turn my engine 1000 rpm faster than it will turn now using one less tooth on the rear sprocket. Or 750 more RPM with two less teeth out back..not much to ask but a lot to do.
.
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with nos you don't get a chance to do plug chops and look see how every things gettin along within your motor...... its usually everything is tuned up and fine then blaaaaaaaa as it melts your piston and head or BANG as it tosses a leg out the cases.....your tune up can be good 1 day and junk the next...... 2 things are for sure with NOS, everyone gets greedy and you will blow something up...
Kent
ABSO-FRIKKIN-LUTELY... ya know that one more step up will make the back-up run fast enough for a record faster than the qualifier....
I don't think you will have problems with the little jets freezing closed, but you need to filter the gas, and put a Murphy switch on it so N20 won't come on unless you have gas pressure.
If you are lucky the first indication of a problem will not be a big hole.... just a little hole or a burned valve... :|
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Another way to put it (what Stainless said) is to try to run a big number on your qualifying run (at Bonneville, that is -- no two-run requirement at Maxton) so you can back it down a tad for your return run. It's really a bummer to grenade the motor on that second run -- when you ran pretty well on the qualifier. As usual -- don't bother to ask me how I know. But -- for the record, see the Photogallery and the section called "Offerings to the Gods of Speed" and you'll see my plugs and a well-ventilated piston. It took about 8 seconds from when I pushed the button -- 'til I needed some internal work on the motor.
Speaking of that part of the gallery: Folks, if you've got photos of the parts that you've damaged and are willing to share 'em -- send them along and I'll get them into that section, too. Not that many folks will be able to learn from your sad situation -- but once in a while we need a good laugh and a reminder that it's not all that uncommon to damage a motor or hurt the tranny (or whatever) when doing this land speed racing thing.
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With Maxton you don't have to back up the last run. We race Five times a year. I need to BETTER the last run every time I go .
I dont think anything will freeze in North Carolina in June. :-P
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I agree with Kent. Stop trying to over think and engineer the kit and the use of it,start with a known setup(the 18hp kit) test it and go race. I'm not a nitrous guru but I used to use it on my talon I used to drag race. As for the tune up I would use your box and pull the timing down a degree or two, jet the n20 so it runs a lot richer than you have been ruining(I don't know na numbers but I would guess somewhere in the high 12 to 1 afr), as good a gas as you can run per the rules, maybe a colder plug(non-projected tip), and last but not least I would start spaying it in 3rd or 4th gear.
All right you motor bike guys it's time to pick apart what I said to see if I'm even close on a bike.
Mike Reichen
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I agree I should just go for the 18 hp set up . It is a lot but lets see what happens. I will drop the compression with a thicker head gasket.and adjust timing accordingly. I will balance the octane requirements of a low compression motor with the needs of the nitrous.
As for spraying in third gear. I am a little afraid to push nitrous in lower gears.The architecture of the engine is not robust.
How did the talon trans hold up?I fooled with them a while back. Seems like they had some trans problems.
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I'm not a n2o guy but I run high 12s afr. would think maybe mid 11s for n2o?
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you don't want to lower the compression for NOS... it will run like a dog turd when your off the button....a dedicated NOS motor is built way different than a gas motor but lowering static and cranking compression is NOT one of the changes
kent
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That is good to know. I am at close to 13 to 1 now. M was going to use 12.5 to 1 for nitrous.
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racer....many ways to skin a cat.....
nothing in stone...all with a grain of salt...
i ran 8.5-1 and was one of the key features of our nitrous
motor...at bonn....for many years...:)
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Edelbrock, and I'm sure all other Nitrous companies, offer blank jets. You can drill them to any size you like. The Edelbrock part number is 73013 for Taper Face Jets and 74000 for Funnel Jets.
JW
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Does running nitrous put you in a different class/category?
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Does running nitrous put you in a different class/category?
YES.. anything "other than" GAS bought from the track vendor puts you in FUEL Class..
So adding Nitrous puts you in Fuel class no matter what else is in your tank.
Charles
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The engine likes timing .The more I advance the timing the more fuel it burns and the more power it seems to make
You need to find a way to retard your timing when you spray or that will be the last run that engine is likely to make. It sucks that MSD can't read your ignition unit because they make one that comes on automatically when you spray, but they aren't the only ones who do.
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no not really.... if yer spraying less than a 50 shot there is no need to retard timing..... but some people like me think spraying anything less than a hun is a waste of time. :-o
kent
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You need to find a way to retard your timing when you spray or that will be the last run that engine is likely to make. It sucks that MSD can't read your ignition unit because they make one that comes on automatically when you spray, but they aren't the only ones who do.
I have an ignition system called a BRT-Tis . I have a switch on the bar. I can select between two maps on the fly. When I make an all motor run I have close to 43 deg of timing across most of the RPM band.
When I spray nitrous I will start with 35 deg across the entire RPM range ( stock ignition curve ) and work from there.
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http://www.ignitech.cz/english/aindex.htm
Have you tried these guys for an ignition unit?
I have one, not installed yet, about 150USD I think
Cheers
Alan
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Thanks for the link . I will look at that.
The BRT is made just for the 250 it is a fully programmable unit and has two maps that can be switched on the fly or with a relay when I spray.
It has a programmable rev limit up to 16000 rpm and the ignition curves are programmable in 16 steps.
In case anyone wants one It is available from Spoptisimotousa
http://www.youtube.com/watch?v=d2GvsiRa7E8