Fangdango! V8 drag car

[Xraycer]

My wife said "I thought this was a Winter project, what will you do now?"

Build a 1:1 version!
You're welcome!

 

[johnnydmd]

Couple of scale comparisons. Interesting that the Viper body is so small that the car looks barely larger than the smaller scale Vette.

My teammates are pretty much "insisting" that I run the car on the list next year, lol. I also think a couple of them will be running similar cars...

Significantly, looks like Toyan is dropping their new V8 this week, that from reviews of its demo in the Germany toy show last Winter looks like a huge improvement over their old one. I don't know the specs, if it's still only 28cc or not (The Cison is 48cc). It does have a killer looking carb on it, much better intake manifold and valve covers. Internals? No idea. Price - rumored to be only 800 dollars. If that is true, and the thing is reasonably well built, this could ignite an entire new segment of RC drag racing.

 

[CertifiedMike]

Couple of scale comparisons. Interesting that the Viper body is so small that the car looks barely larger than the smaller scale Vette.

View attachment 208522
View attachment 208523

My teammates are pretty much "insisting" that I run the car on the list next year, lol. I also think a couple of them will be running similar cars...

Significantly, looks like Toyan is dropping their new V8 this week, that from reviews of its demo in the Germany toy show last Winter looks like a huge improvement over their old one. I don't know the specs, if it's still only 28cc or not (The Cison is 48cc). It does have a killer looking carb on it, much better intake manifold and valve covers. Internals? No idea. Price - rumored to be only 800 dollars. If that is true, and the thing is reasonably well built, this could ignite an entire new segment of RC drag racing.

I would never have expected to see a revival in drag racing with the current trends in technology.

Its SO cool to see it happening at the scale level!

Those cars look GREAT side by side! Nice paint work!!!

 

[johnnydmd]

I didn't get to test as planned as we had a party on Saturday and went to one on Sunday. Good times

I did fire the engine up a few times, and Sunday night I took the plugs out to inspect. Some were a little dirty, others looked completely new. Closer inspection revealed that the wires on the ones that looked new were NOT making contact. I cleaned all the plugs up, redid the wiring and went to bed. Next day it totally dawned on me how the things were supposed to be done (there is literally no instructions, and nobody seems to know how so everyone just does them their own way). I tried what I think they wanted and fired the engine up. Well, it ran amazing. For about a minute. Then the contact became bad from vibration, and the engine was misfiring horrendously, spewing and belching, now clearly misfiring. I also sprung another massive coolant leak, which also got all over the hall sensor connection on the distributer probably causing some of the misfiring too. Sigh. It's whack-a-mole with the coolant. This spot was definitely due to a little bit of poor design, but it really came down to another hose needing a clamp.

I took the engine out and front end off and cleaned everything up. I redid the wires, and this time did it like originally, but better, this time coiling the wire ends and hitting with a little solder (just on the distributer side, no solder on the plug side coils). I don't think I'll have any spark issues now. This will make great contact.

While the engine was out, changed the oil. It wasn't too bad this time. I also took my valve covers off to re-check and inspect the rockers. All was good, so I went ahead and re-sealed. I had run it the last time without re-sealing, and I can rest assured that PLENTY of oil gets to the top of the engine, as I saw it dripping out from the valve covers. There is some optional thing where you can route more oil up there (In the instructions it even says "not necessary"), and a few guys have done it, but I strongly suspect that causes more harm than good as it takes away oil from the rest of the engine, and the amount I'm seeing in the top end is plenty.

Re-filled the coolant, and fired it back up for a few seconds, and it seemed happy again, and was extremely responsive. I still need to fine tune the carb. I had it pretty good, then kinda mucked it when it was misfiring thinking that was the issue. By now the garage smelled like crap (like a poorly running engine, lol) even with my fan blowing it out. Didn't want to get in trouble again The good news also was that I saw no coolant spewing anywhere. Finally.

Make a makeshift dipstick as well and marked it. That would just be useful on a race day to make sure oil was good. I cut a hole in the bottom of the chassis under the drain plug so that I can easily change the oil now without having to suck it out or remove the engine. That's something I'll do after each use of the car.

One other thing I've been pondering, is some kind of fuel pump. Maybe something to attach to the inlet that was for the nitro exhaust to pump air into the tank. Not sure about that yet. Small aerator?

 

[CertifiedMike]

Sounds like a bit of the "one step forward, one step back" 2step!
I'm glad you caught the issues now!
The picture of the coiled wire made my hands hurt!

Great update!!!

 

[Doom!]

I would be so lost. I'm glad you know what your doing.

 

[johnnydmd]

Ran the engine some more last night and tuned it a bit. Seems to be consistently firing on all cylinders now No leakage whatsoever coming from the engine...but...a puddle appeared under the radiator! Further inspection revealed that my overflow tank was leaking due to some small cracks around the fitting at the bottom that drains into the radiator. This happened because I replace the original fitting with a different one and had to drill the hole out, I didn't make it big enough and I guess the pressure when screwing it in caused the cracks. Hit it first with some gap filling superglue, then put silicone sealant over all of that. Filled the tank up and left overnight, and finally, NO LEAKS.

I also got some advice on the plug wires from some others. At some point I will make proper contacts - it can be done pretty similarly to how the 1:1 stuff is actually. For now, though, what I have is working fine. The engine was idling very well, didn't notice any misfires whatsoever once it warmed up and cleared out all the oil/fuel from the previous day's shenanigans. Played with the HSN some, and got it pretty dialed in. I also got a tip for wire management and took it:

That's just basically using fuel line with slits in them and supergluing it together. The new tach/sensors for the CDI comes soon (original one was defective), so I'll be able to see some real data.

I also got a nice pic of the car out in the wild (well, my driveway):

Saturday I will be testing with some friends (who are also looking to build their own versions). Should be fun! Many questions could be answered.

One question that will probably linger, is power adders. I have turbos. But...it appears that Mr Cison is in the process of developing a roots blower for this engine! If that's the case, that will 100% be the route I go if adding power. Much easier and much better since there's no lag.

The other thing I mentioned before was fuel delivery. The car seems to do ok, but I do notice it leaning out, especially when it gets warmed up. I realize most engines are gonna idle higher when hotter, but I'm also seeing that it's kind of a vicious cycle with this setup. I also foresee that under acceleration it could *really* starve. I looked around and found tiny 3v aerators for aquariums that I could use to pressurize the fuel tank once the engine is running. I think.

 

[Xraycer]

Ran the engine some more last night and tuned it a bit. Seems to be consistently firing on all cylinders now No leakage whatsoever coming from the engine...but...a puddle appeared under the radiator! Further inspection revealed that my overflow tank was leaking due to some small cracks around the fitting at the bottom that drains into the radiator. This happened because I replace the original fitting with a different one and had to drill the hole out, I didn't make it big enough and I guess the pressure when screwing it in caused the cracks. Hit it first with some gap filling superglue, then put silicone sealant over all of that. Filled the tank up and left overnight, and finally, NO LEAKS.

I also got some advice on the plug wires from some others. At some point I will make proper contacts - it can be done pretty similarly to how the 1:1 stuff is actually. For now, though, what I have is working fine. The engine was idling very well, didn't notice any misfires whatsoever once it warmed up and cleared out all the oil/fuel from the previous day's shenanigans. Played with the HSN some, and got it pretty dialed in. I also got a tip for wire management and took it:
View attachment 209151

That's just basically using fuel line with slits in them and supergluing it together. The new tach/sensors for the CDI comes soon (original one was defective), so I'll be able to see some real data.

I also got a nice pic of the car out in the wild (well, my driveway):
View attachment 209152

Saturday I will be testing with some friends (who are also looking to build their own versions). Should be fun! Many questions could be answered.

One question that will probably linger, is power adders. I have turbos. But...it appears that Mr Cison is in the process of developing a roots blower for this engine! If that's the case, that will 100% be the route I go if adding power. Much easier and much better since there's no lag.

The other thing I mentioned before was fuel delivery. The car seems to do ok, but I do notice it leaning out, especially when it gets warmed up. I realize most engines are gonna idle higher when hotter, but I'm also seeing that it's kind of a vicious cycle with this setup. I also foresee that under acceleration it could *really* starve. I looked around and found tiny 3v aerators for aquariums that I could use to pressurize the fuel tank once the engine is running. I think.
View attachment 209153

Well, this is easily a ROTM winner, once you're eligible again.

 

[Doom!]

I'm pretty sure this would be rig of the year.

 

[CertifiedMike]

Ran the engine some more last night and tuned it a bit. Seems to be consistently firing on all cylinders now No leakage whatsoever coming from the engine...but...a puddle appeared under the radiator! Further inspection revealed that my overflow tank was leaking due to some small cracks around the fitting at the bottom that drains into the radiator. This happened because I replace the original fitting with a different one and had to drill the hole out, I didn't make it big enough and I guess the pressure when screwing it in caused the cracks. Hit it first with some gap filling superglue, then put silicone sealant over all of that. Filled the tank up and left overnight, and finally, NO LEAKS.

I also got some advice on the plug wires from some others. At some point I will make proper contacts - it can be done pretty similarly to how the 1:1 stuff is actually. For now, though, what I have is working fine. The engine was idling very well, didn't notice any misfires whatsoever once it warmed up and cleared out all the oil/fuel from the previous day's shenanigans. Played with the HSN some, and got it pretty dialed in. I also got a tip for wire management and took it:
View attachment 209151

That's just basically using fuel line with slits in them and supergluing it together. The new tach/sensors for the CDI comes soon (original one was defective), so I'll be able to see some real data.

I also got a nice pic of the car out in the wild (well, my driveway):
View attachment 209152

Saturday I will be testing with some friends (who are also looking to build their own versions). Should be fun! Many questions could be answered.

One question that will probably linger, is power adders. I have turbos. But...it appears that Mr Cison is in the process of developing a roots blower for this engine! If that's the case, that will 100% be the route I go if adding power. Much easier and much better since there's no lag.

The other thing I mentioned before was fuel delivery. The car seems to do ok, but I do notice it leaning out, especially when it gets warmed up. I realize most engines are gonna idle higher when hotter, but I'm also seeing that it's kind of a vicious cycle with this setup. I also foresee that under acceleration it could *really* starve. I looked around and found tiny 3v aerators for aquariums that I could use to pressurize the fuel tank once the engine is running. I think.
View attachment 209153

I haven't a clue if one would work/help for your fuel issues but boost bottles were designed to catch some reversionary back pressure in the lines caused by the single cylinder draw/fire cycle.
It looks good on paper.
If I recall, they weren't a big hit for nitro but it doesn't mean it couldn't work here.
I have ZERO exerience with them but I was reading about them less than a week ago...
Maybe???

"Build of the year" vote just placed!

 

[johnnydmd]

Some people have expressed ideas about it. Boost bottle, or something to capture air off the exhaust, not sure. Someone also mentioned a float cutoff like a regular carb. That actually might be easy enough to do.

 

[CertifiedMike]

My nitro Kyosho uses a button to pump pressure into the tank at start and a line from muffler into tank.
Maybe its worth a shot?
I thought it was too much coincidence t have "happened" on the boost bottle article, then this and not mention it at least.
Seems like they can be had cheap on thebay for an experiment if building one isn't realistic.

That blower would turn this whole idea on its head!
Are they releasing a gear drive fuel pump for this thing too???

The whole build is TOO COOL!!!

 

[Xraycer]

I'm pretty sure this would be rig of the year.

Now, don't go getting all crazy! I do now, own an rtr Kyosho Datsun 240z!

 

[332_RC]

Well, this is easily a ROTM winner, once you're eligible again.

ROTM???? How about the year?

 

[johnnydmd]

My nitro Kyosho uses a button to pump pressure into the tank at start and a line from muffler into tank.
Maybe its worth a shot?
I thought it was too much coincidence t have "happened" on the boost bottle article, then this and not mention it at least.
Seems like they can be had cheap on thebay for an experiment if building one isn't realistic.

That blower would turn this whole idea on its head!
Are they releasing a gear drive fuel pump for this thing too???

The whole build is TOO COOL!!!

No idea if they would release a fuel pump. A few have mentioned a line from the exhaust, but there's a few problems with that I think. One, that I'm running open headers, and also that I don't want exhaust pressure like a nitro, that would murder performance.

Some have mentioned oscillating Perry pumps, which is intriguing, but not really sure where I could mount it on the engine block.

Others mentioned needing a float, but I'm really only looking to add small pressure in the tank to keep the fuel moving and not relying entire on suction, I plan on using a control valve to adjust, and it'll only run when the engine is running.

 

[johnnydmd]

This weekend I had a lot of free time, and it got spent on this car. First thing I did was head out and get some proper fuel!

I love the smell of that stuff

Saturday, I took the car out and decided to drive it around an empty parking lot. Engine fired up, and I started tweaking the needles. After a bit, I got it running well, and started trying to just lightly drive it around. Man, it did not get far at all! Just giving it the slightest amount of throttle and the car was wildly spinning out. No doubt far too light in the rear and nose heavy. This is definitely a combo of things, but I clearly need to replace the axle housing with the heavier titanium one (on order). I also note that the front servo was jerking around a lot whenever I gave it decent throttle. This was likely due to 1) It being a cruddy 10 dollar servo, as my throttle servo was fine and 2) Loose wiring on the distributor/plugs causing noise. Minor stuff though. I was incredibly impressed with the raw power the engine has. My biggest question was how fast would this thing be, and I think my answer is that it's going to be very, very fast.

My next issue was when I got home, cleaning the car up, was just a hassle. The open headers inside the thing just get fuel and crud everywhere on the rear section of the chassis. It was high time to put my exhaust on! So I got to doing that...

Nothing fancy, just some gently bent copper tubing with a hanger. Heat shrink tubing to insulate the chassis and body. Didn't really lose any of the awesome open header sound either. Reminds me a lot of the exhaust I had on my 71 Camaro in my punk street racing days

I do like when a plan works out.

So now it was Sunday, and I was mostly interested in tuning the engine and figuring out why the servo might be acting whacky. I had the car in my driveway and on the street, just goofing around. Man, the way this thing sounds, it simply just roars like a real car. Even just lightly tooling around, the thing just sounds scary as hell. I fiddled around with carb settings had it purring nicely for a bit, then not, then purring. Thing just seemed all over the place. One thing, my ignition battery (9v rechargeable) was low, so I have two, and swapped it, and the car was happy again. I also noticed that the plug wire caps on the distributer, a few of them anyway, kept getting loose. I honestly hate the design. Look below, and tell me how is anything supposed to stay connected? Why in the word do they not have some kind of either threaded end, or snap end?

My wife said put clamps on the boots. Maybe not a bad idea, but there's no room to do it. I decided to try something, which was take an m2 nut, and bore out the hole some to make a contact that would tightly fit on the posts and solder it to the wires.

Then I shoved the nut up into the boot, and put it on the cap. Seems to fit really snug. Hoping this will work. For the plug ends, my buddy came up with an idea that was great, which was to take a section of the spring from the glow plug wire from a Traxxas car and see if it would snap over the spark plug ends, and sure enough, it's the perfect size. The wire just slips in (tightly) into the end of the spring section. Haven't done it yet because so far, I think that plug boots are staying quite snug on the plugs.

I also alleviated any fuel flow concerns. I was not seeing any air in the line when revving, and so I'm not going to bother with the pump. I did test to see if it worked, and it did build slight pressure in the tank. It's something I can worry about later under much harder acceleration tests.

I had planned on taking some video. My phone was set up, but I hit the wrong button, and did not check until I put everything away. I'll get some very soon though.

With the car on the jacks, I noticed the oil was getting funky after all that running over the weekend. Drained it, and inspected it.

Looks like a good mix of brass from the crank bearings/connecting rods, and carbon steel from the rings. I think that is to be expected as the engine breaks in, but no doubt it's a good idea to change the oil after each use. The engine still feels pretty tight when turning by hand, so it's got a ways to go yet before break-in is done.

The other problems I had was the throttle linkage binding slightly, and the carb needles. I think I'm getting closer on those, but it's hard to tell when you keep dropping cylinders due to loose wires. I also need to properly set the timing. I could do it by ear, but I'll see about getting a timing gun. The last thing is coolant spillage out of the overflow tank. Not much I can really do about that one, other than not put too much in the system. However, too low, and the system draws air, and tends to run too hot and blow steam out the little hole in the tank. I think I'm going to put a fitting in the hole and run a line somewhere less obnoxious that getting all over the front of the engine.

 

[thrak76]

I really enjoy your updates @johnnydmd. So much tinkering, as compared to plug-in-and-play electric rigs...

 

[Doom!]

I really enjoy your updates @johnnydmd. So much tinkering, as compared to plug-in-and-play electric rigs...

I enjoy @johnnydmd 's updates, and still thank god for plug an play electric rigs!

 

[Xraycer]

I love when people take their passion to another level..........or 1000!

 

[johnnydmd]

Last night something occurred to me about the amount power when speccing this thing out vs a nitro (or brushless) car. I was focusing on HP, I should have been looking at torque.

Based on manufacturer's numbers for HP for this engine (4.8 at 10000 rpm) vs an OS .21 (2.8 x 42000 rpm) - that calculates out to the V8 having 7x more torque than a big block nitro. And about 3-5 times more torque than a 2s brushless car.

I can believe this is reasonably accurate based on what I was seeing. I do have to add weight to the rear, and get the weight transfer much better, or it's not going to be very controllable.