When it rains it pours!

[UncagedShadow]

I see, that was my main concern. I was almost certain the stoich mixture rates would not allow a proper and long term mixture of the two.

I have heard of the conflicting designs of top fuel vs gasoline drag engines. I am persuing my automotive technology degree at the moment. At my school, Antron Brown(driver of the matco tools top fuel dragster) was a guest speaker and brought his car. Unexplainable in words being able to talk to this guy and see his car. Learned alot of great stuff.

I have recently been reading up on the massive fuel requirements/flow needed to maintain an engine run off of nitro. The powerjet and fuel pump ideas you posted sparked this interest. I have learned that to run methanol, one needs to have their fuel flowing at about 2.5 times that of a gasoline powered engine. Therefore, i can infer from BTU output differences and fuel amounts per air charge need in each stroke that to run nitromethane, one may need 4-5 times the fuel flow of a gas engine. Am i correct in this inference(more assumption)?

 

[sicivicdude]

I've seen quoted 4-7 times the fuel flow for pure nitromethane fueled engines vs gasoline simply because of the amount of oxygen in the liquid.

I'm thinking I'll need about three times the fuel flow (of a similar output "gasser" engine) which is why I started down the path of fuel pump and HUGE carb and powerjet (plus huge main and shaved needle) to begin with. I figured 600cc's of fuel needed to run 300ft at 25% nitro blend. The amount of fuel needed is astounding when compared to a stock blaster going the same distance.

 

[UncagedShadow]

Yes the amount of needed fuel that you calculated is absolutely astounding. But therein lies the potential of nitromethane. You can squeeze some much more nitrometh into the blasty cylinder than gasoline, thus making you sh*t you pants on the first ride. At least that is what i forsee in the future.

Now you are going stock bore and stroke with a custom pipe, huge carb, and of course nitrometh mix as your fuel.

As much as a 240 would be nice to do this with(cuz as we all know, there is no replacement for displacement), the piston issue is still the biggest turn off for me. So, my plans have been to use a +4 crank, maybe a 40mm carb, custom built pipe, and i plan to attempt a retro fit a fuel pump off a carbed street bike.

Keep in mind I will not even be starting this radical build until I have graduated and have some dough to throw around. I am excited that a fellow blasty bro has the gears in his head turning the same way my gears are turning. But not to take the spotlight off of civic.

The trophy for craziest, yet most awesome fuggin' member on blasterforum goes to my main man "sicivicdude".

Anything you need, I here bro.

 

[sicivicdude]

But who else is crazy enough to do this kinda stuff with a STOCK blaster? We're talking 197cc engine (66.50mm) and a stock frame..... who else can say that?

This fuel pump is just like the one which might come on a carb'd street bike. I do need to change out two of the nipples. I need to get two 3/8" drive in nipples and drill out those 1/4".

 

[UncagedShadow]

Haha you are very right civic. It will be nice to see how fast this nearly stock setup is. People around my parts and around my local track dog blasters all day, saying they are worthless quads that have no potential to be competitivley fast. 1 or 2 have given me props on how easily I can manipulate my blaster when on the trails. Another guy wants to get one after i passed him on a trail in a spot his raptor 660 couldn't fit through. Now something like this blasty of yours could make people respect the blaster seeing that you will be runnign a stock bore and stroke.

 

[sicivicdude]

Funny part is if this really is fast, no one will actually believe it.... everyone will think I'm "cheating" somehow. I don't consider fuel choices to be cheating but no one will believe it's a stock bore and stock stroke.

 

[UncagedShadow]

Ya, the haters will always find something to complain about or some reason why you won and they lost, other than your faster than them.

Fuel is a major part in high performance engines. Top fuel cars prove that. I mean they run 500ci engines with superchargers. Not totally crazy except they can put out 6000 to 10,000 horsepower and anywheres from 7000 to 9000 ft lbs of torque. None of these numbers are truly confirmed though becasue although they do have dynomometers that can measure top fuel cars, most of these engines can not operate at full power for more than 7-10 seconds without grenading.

 

[04YamahaRider]

Same stuff there. The rc cars run nitromethane. Same thing he plans to run. Same thing I am planning on running in the future. It can be done since the 2 stroke r/c cars love to drink some nitrometh, its just it hasnt been done often enough with quads and bikes to have all the tuning info at easy access.

Some interesting facts about nitromethane.

14.7 lbs. of air is required to burn 1 pound of gasoline, but only 1.7 lb. of air for 1 lb. of nitromethane. Since an engine’s cylinder can only contain a limited amount of air on each stroke, 8.7 times more nitromethane than gasoline can be burned in one stroke. Nitromethane, however, has a lower energy density: Gasoline provides about 42–44 MJ/kg whereas nitromethane provides only 11.3 MJ/kg. This analysis indicates that nitromethane generates about 2.3 times the power of gasoline when combined with a given amount of oxygen.

Nitromethane has a laminar combustion velocity of approx. 0.5 m/s, somewhat higher than gasoline, thus making it suitable for high speed engines. It also has a somewhat higher flame temperature of about 2,400 °C (4,352 °F). The high heat of vaporization of 0.56 MJ/kg together with the high fuel flow provides significant cooling of the incoming charge (about twice that of methanol), resulting in reasonably low temperatures.
Nitromethane is usually used with rich air/fuel mixtures because it provides power even in the absence of atmospheric oxygen. When rich air/fuel mixtures are used, hydrogen and carbon monoxide are two of the combustion products. These gases often ignite, sometimes spectacularly, as the normally very rich mixtures of the still burning fuel exits the exhaust ports. Very rich mixtures are necessary to reduce the temperature of combustion chamber hot parts in order to control pre-ignition and subsequent detonation. Operational details depend on the particular mixture and engine characteristics.

A small amount of hydrazine blended in nitromethane can increase the power output even further. With nitromethane, hydrazine forms an explosive salt that is again a monopropellant. This unstable mixture poses a severe safety hazard, and is forbidden for use in model aircraft fuels.
In model aircraft and car glow fuel, the primary ingredient is generally methanol with some nitromethane (0% to 65%, but rarely over 30% since nitromethane is expensive compared to methanol) and 10–20% lubricants (usually castor oil and/or synthetic oil). Even moderate amounts of nitromethane tend to increase the power created by the engine (as the limiting factor is often the air intake), making the engine easier to tune (adjust for the proper air/fuel ratio).

OK you my friend have now fried my brain haha but yeah i know, i have a 1/8 nitro truggy thats why i suggested that and b/c i dont understand all the technical talk so i wouldn't have known lol

 

[sicivicdude]

Alright, slip roll ordered. I'll be going through all that when it arrives.

I contacted the manufacturer and they answered a bunch of questions I had and gave me a warm fuzzy feeling about this machine. It looks like it'll work for a long long time.

It's a Woodward-Fab model WFSR12.

 

[Surfrjag]

This is gonna be saweet! I'm definitly staying tinned in for this! Btw that crank deal is awsome. The next bottom end I do I will be sending it to get rebuilt I don't think anyone can beat that price.

 

[sicivicdude]

This is gonna be saweet! I'm definitly staying tinned in for this! Btw that crank deal is awsome. The next bottom end I do I will be sending it to get rebuilt I don't think anyone can beat that price.

That price is his "deal" for everyone who mentions the blaster forum, $99 including return shipping. I don't think anyone can touch that price either, I'm thinking about getting another crank done just to have a spare.

 

[UncagedShadow]

Man that guy is crazy nice to be giving us a deal as good as that just for advertising his crank rebuild service. I was going to just get a stroker soon since my rod went on my crank, but I may just send him that crank for the 99$ and run it.

 

[sicivicdude]

That's not even for advertising or anything. He apparently got a huge lot of yammy rod kits and can afford to turn them back out reasonably priced.

I specifically inquired about his "sustainable" price for crankshaft rebuilds. He said $99 shipped is what he can do them for and make enough profit to KEEP doing them.

Obviously, this isn't for the performance enthusiast, mainly for those who are just going back with stock and don't want to risk a made-in-taiwan-who-knows-what crank and would like to save about $40 in the process LOL.

 

[UncagedShadow]

Ya I guess that makes alot more sense. But considering a stock crank brand new is 140-150+ and no measurments are checked, and a stroker is about 180+ and not clearanced either, this is the deal of the century for someone with a bad rod on their stock crank.

Question... Did you inquire on rebuilds of any stroker cranks? I.E. only needing a rod.

 

[sicivicdude]

I didn't inquire about stroker cranks. I know the +4 hot rods stroker uses a stock rod and this rod could be pressed onto the crank ends just like a stock stroke crank. Probably the same price.

The Vito's +3 stroker uses a thinner big end rod end and this rod COULD be pressed onto those crank ends it would require trenching to run the thicker big end rod end.

 

[UncagedShadow]

The Vito's +3 stroker uses a thinner big end rod end and this rod COULD be pressed onto those crank ends it would require trenching to run the thicker big end rod end.

This could be useful info. Theoretically, I could pick up a +3 stroker with a shot rod, and have the stock rod pressed on therefore making it a stronger +3 crank? The trenching would be worth it becasue you could run both the +3 or +4 crank. I might be on the lookout for a +3 or +4 crank with a shot rod to do this with. I would prefer a +4 though since I am doing the trenching.

 

[sicivicdude]

So I've had a couple of thoughts and done a little thinking. Some good, and some bad.

I've couple up with a few things and figured I'd share:

I said I'm going to use a stock frame. Let me clarify, I'm going to be using a stock FUNCTIONAL frame. In other words I am going to modify it slightly but the modifications aren't going to impeded its ability to operate as a stock frame. Specifically, I'm going to have all of the stock mounting tabs and everything but I'm going to have to modify the motor mounts considerably. The power targets I'm talking about would rip the front motor mount clean off the frame in a second. I'm going to use a set of regular cases to mock up new motor mounts using the stock location and everything but the new motor mounts are going to be longer and wrap all the way around the drop tube (and possibly be gussetted to the lower tubes as well). While this won't ACTUALLY be stock, it will be stock in function (I'm going to make it where it doesn't interfere with any of the stock stuff where you could theoretically revert this frame back to a completely stock quad) which is good enough for me.

There are two areas of damage which will have to be repaired before I can use this frame from it's previous life. One the of the "nut-serts" welded into the bracket for the grab bar is ripped out. I'll have to repair that area. It will be repaired to back to a "stock" configuration. One of the chain roller tubes has been ground off the frame and I'll have to do something about that (although for this purpose I probably won't need rollers I'd like to fix it back up anyway). Both of those areas will heopfully be reparied to a "stock" like function even though damage to the factory yamaha parts means I can't reuse the factory pieces.

I'm going to be using a blaster cylinder which is actually going to be a .010" or .020" (I can't remember which one it needs to go to now) oversize. I said "stock" but I wasn't really thinking about stock vs overbore size. What I mean by stock is stock yamaha cylinder and yamaha sleeve (not a big bore). I'm going to be making a few modifications in the name of power that some may or may not be kosher with. First off, the stock reed cage is not enough flow for this PJ38. I'm looking into a CR125 reed cage to stick into the cylinder. I've already got it on my BBK stroker trail quad but I'm thinking I'll need that extra flow when this thing is screaming. While that reed cage is not stock yamaha, I'm sure most can look over that fact considering it's not some crazy zany mod...just a relatively small one. The porting is going to be crazy harsh as this is only going to be a "top-end" motor anyway... I'll take pictures as I go of all of the work. I'm also thinking about upgrading all of the hold down hardware to M10 fine thread grade 12.9 stuff. I know that the cylinder mounting studs aren't up to the task of holding down this sort of power so they'll have to be changed out either way but I'm considering changing out all of it to hardened M10 stuff. Cylinder hold down bolts and head studs. It will take a bunch of work to get all of the hardware changed out but I think this is necessary to make sure the engine doesn't see an untimely demise simply because the bolts holding the assembly together aren't up to the task. I'm also thinking about making cylinder hold down tab supports out of steel. The cylinder hold down pieces are more than adequate for a stock quad but I want to make sure I distribute the load of the explosion this engine is going to create evenly around the mounting tabs. I'm thinking about making steel contoured caps to go under the nuts to sit on top of the aluminum and help spread some of the load. Anyone have thoughts on this?

I'm going to be manufacturing a pipe. This pipe will be fitted to my porting for the power output goals I'm shooting for. The first version will probably be a silenced Out Of Frame pipe. My goal is to make a pipe which I can test this engine combo with and make sure (before I spend ungodly amounts of hours handrolling an inframe drag pipe) that this is all going to work together. Super noober has already expressed interest LOL in purchasing it after I've confirmed the pipe is what I'm looking for. The "final" version will be an in frame pipe, it might be a little un-conventional but it will fit back into the frame before I'm done with it.

I'm going to have a maier white rear plastic, stock hood and stock tank cover but probably no front fenders. I don't really see the need for front fenders on a drag bike, fenders keep the front tires from throwing stuff up in your face. Drag bikes don't turn a lot and the front tires are going to be bald. I will retain the mounting tabs in case I find a good deal on some front fenders in the future but right now I don't have an fenders to run and don't see the point in finding any.

I'm taking the original stock fuel tank off and running an almost completely empty tank cover. After runs with methanol and nitro the entire fuel system and engine need to be purged because the fuel is corrosive and if left sitting in aluminum would eat it. I'm planning on putting a valve just outside the carb inlet (basically where the fuel valve is stock) to allow me to swtich between a very small container of mixed gasoline put where the stock fuel tank is and the fuel pump/new fuel tank which will be located inside the front bumper. All of these aftermarket components will be securely mounted utilizing the stock mounting tabs for other things.

I'm thinking about modifying the steering stem. I know some will cry "foul!" over the stock frame part but I believe in order to make single plane drag spindles work well, I need to turn the flag around and drop it down so the tie rods pass out in front of the flag pivot point. Otherwise my tie rods are going to be pointed WAY foward and the ackerman angles will be TERRIBLE. Considering you don't want the wheels of a dragger to turn that much anyway, I may make this happen. I have an old bent steering stem I may tinker with when the time comes for the front suspension. In order to maintain the "stock" moniker, I won't modify anything but the stem itself. I'll make sure a different stem could be put right back in it would be like stock.

 

[cole454]

Holy huge post!!

But sounds good. I:I

For the rollers, cut off the factory mounting and use these
http://cgi.ebay.com/ebaymotors/_W0QQcmdZViewItemQQ_trksidZp3984Q2em1438Q2el2649QQitemZ180639631001QQsspagenameZSTRKQ3aMEWAXQ3aIT

 

[UncagedShadow]

I dont think anyone is going to be judging your build based off a stock vs aftermarket/modded list. Its your bike and no one elses. I think the idea is cool and will be awesome when finished, but alot of people that run drag bikes have literally replaced almost every part on their bike in the pursuit of speed.

 

[sicivicdude]

I dont think anyone is going to be judging your build based off a stock vs aftermarket/modded list. Its your bike and no one elses. I think the idea is cool and will be awesome when finished, but alot of people that run drag bikes have literally replaced almost every part on their bike in the pursuit of speed.

Well that's kind of my idea behind this. I'm not trying to have a HUGE budget here. Most of the stuff I'm going to be doing here could be done by someone with regular tools (some of the welding is a little much maybe) on a regular budget. I'm trying to get as fast as possible without blowing the bank. A lot of the mods I'm doing are to keep costs down and make this simple enough to build while still making it FAST.

Cole, I'm thinking about repairing the stud so I can say that the frame is stock but not using those rollers anyway. I was thinking about making a tray for the chain to slide in. The suspension is going to be ridgid anyway.