Nitro questions.

[Zippo25]

I have a few nitro questions for all you engine guru's. I've been reading a lot recently about "turbo" engines. What exactly qualifies as a turbo engine? i've seen some with agressive porting or turbo plugs.. what makes a plug a turbo plug? Also.. and bear with me here. i've seen some racers wrap a loop of fuel line around the bottom of their cooling heads.. does anyone know why? does heating the fuel maximize the vaporization or something? Anyways, thanks for the help.


Jo

 

[Clintd]

I know the turbo plug's are taperd and have no gasket like a regular spark plug. and the port timing is usaly radicly different on a turbo engine.

 

[olds97_lss]

Yeah, it has to do with the shape of the head plug where the glow plug goes in. It makes a nice flush surface inside the head. It's also more prone to airleaks because you don't use a brass washer on the glowplug to make the seal.

 

[SkyMaxx]

Turbo engines are usually ported a bit differently and the glo plugs typically have an ignitor bar across the gap. Aside from that, I can not give specifics on what makes a turbo engine a true turbo engine.

 

[olds97_lss]

An ignitor bar? Like an idle bar?

 

[SkyMaxx]

Same thing...small portion of plug body that goes over the coil. Makes the plug resemble a spark plug from your car.

 

[Monkey Wrench]

Same thing...small portion of plug body that goes over the coil. Makes the plug resemble a spark plug from your car.

Huh, I didn't know that. I have a WASP .28 with the turbo head and have been using the OS turbo plugs. I can see where the end is tapered down, but it has no bar across the bottom. Is there a particular manufacturer that has this? May explain why it can be a PITA sometimes to run!

Thanks!

 

[SkyMaxx]

Before you run out and buy the plug I described, let me clarify something based on Olds post and my own misreading. The turbo plugs that were described prior to my post are accurately described (the package of a turbo plug should be so labeled.) The plugs I described are a turbo plug with an idle/ignitor bar. Not all plugs with this idle bar are turbo plugs and not all engines will take a plug with an idle bar. Before just dropping a turbo plug into your mill, make certain your mill is made to handle a turbo plug or a plug with an idle bar. MW, my money is on the WASP not needing the idle bar, but will need to look into the owners manual on it to be certain.

-SkyMaxx

PS...In other words I misread the post and responded with not 100% correct information...also known as a mistake. My apologies if I got anyone going down the wrong path.

 

[olds97_lss]

Man... nothing but lies and fairy tails!

Sorry about questioning you. I've only read about turbo engines. I thought glow plugs with the bar thing were more for newbies to help the engines idle. It would have never crossed my mind that something like that would have been on a "performance" engine as a standard.

 

[SkyMaxx]

Question away. That is why we have this board...to ask questions. If someone puts out the wrong information, we are all here to make certain it gets corrected. Moderators make mistakes. Just because I am a moderator, does not mean I know everything about a question. It simply means I get to enforce the rules of the forum.

 

[olds97_lss]

Any idea what the little bar is for? Or is it something different than an idle bar?

 

[SkyMaxx]

I'd have to look it up. Used to know, but it has been a little bit since I was last discussing the finer points of glo plugs. What I do know is that most engines do not work so well with them and most engines are not really designed for them. That is why I recommend checking the owner's manual for the engine in question. They are usually really good about defining what and what can not be used in the engine.

While I generally do not like making mistakes, I do like to make certain I find the correct answer and put it out there. So, Olds...here is what I found out about the infamous idle bar.

IDLE BARS

Idle bar glow plugs came about because some engines were having trouble transitioning from idle to high speed. When the throttle was opened from idle, the incoming air and raw fuel would strike the glow plug's heated coil, cooling it to the point where it would no longer support the combustion process, so the engine would die. To help prevent this, the idle bar was added to the glow plug to serve as a physical shield, helping to keep the coil from cooling off too quickly.

A glow plug with an idle bar will not increase peak RPM (it may even reduce it in some cases), but it may improve the idle with some engines, since it simply helps to keep the plug hot enough to light the fuel. If your having transition problems, you might want to try using a glow plug with an idle bar. Some modelers use idle bar plugs in the winter only, since the glow plug tends to loose heat faster in the colder environment.

Naturally, all of this assumes that you have the low speed mixture adjusted correctly to begin with.

The above information came from this site, and is a direct quote: http://www.scootworks.com/rdrc/gloplugs.html

Here is an image of a turbo plug:

Click the following link at OS. The first bullet on the site gives information about turbo engines versus standard.

http://www.osengines.com/accys/choosing-glowplugs.html

Hope this sets the questions to rest and makes up for my goof up.

-SkyMaxx