Bubbles in fuel line and tuning

[crabbdean]

I'll start this as a new topic as I want to cover some ground on it
that may not be related to the previous post. I'll prefix the post
with the the end of the previous thread as a lead in.

===============

> Being new to this ... I can imagine bubbles in the fuel line aren't
> desirable. I noticed this on mine the other day. Not bieng a racing
> guy, although I may work up to that, are bubbles necessarily bad for a
> beginner like me? Does it damage the engine? Is it just a matter of
> tuning to get rid of them?

> Ta
> Dean

Doc wrote:

Dean,
Yes, bubbles are bad. What's important is WHY the bubbles are there.
There
are two reasons:

1) Hole in fuel line
2) Engine is overheating, fuel is boiling/evaporating inside the carb
and
blowing fuel and bubbles out of the cab, thru the fuel line back
towards the
fuel tank.

A few little bubbles here and there are normal, a constant stream of
bubbles
or several large bubbles indicates one of the two above scenarios and
needs
to be immediately rectified.

An on-board temp gauge such as MIP's is highly recommended for nitro
newbs
in my book! I'm an experienced tuner and I still use em'. Some will
balk
at this idea and to them I say: would you drive your 1:1 vehicle w/o a
temp
gauge or idiot light of some sort?

Doc

======================

So, I got my car out on the weekend, this is my second weekend out, and
now starting to play a little with tuning. I want to relay some of the
experience I had on the weekend to get feedback on it.

When I first started to run the car and tune it, it appeared to go okay
but at full throttle it would choke and stall. Initially I thought was
running too rich so tried to lean it out more - still had the same
problem. Then I noticed after it choked at full speed that there were
massive bubbles in the fuel line. Riching the mixture more and it ran
fine. I'm not sure of the cause behind this. Is it because of what
Doc explains above in point 2??

Also I noticed it was sugglish off the start. I think I leaned out the
bottom end a bit and it was much quicker off the mark. Can someone
explain to me the theory behind this also. What am I looking for?

Thanks
Dean

PS. Also took some video on the weekend. I'll try and get find an FTP
site I can upload it to.

[crabbdean]

"Doc" wrote:

> HSN is adjusted properly when you get good top speed, a nice smoke trail at
> WOT and temps between 240*-300*F.
>

Thanks Doc, that's really helpful. I hope the wording of my question
didn't come across as not trusting your information, it was just the
way I (badly) worded it.

The temps provided above... I found my car going over this range the
other day, up to (and over) 250 deg cel. I'm wondering if the temp
varies based on engine size? Mine is a .21, does that make a
difference? Does the high temp suggest I'm running too lean?

I really want to get out with my car and do quite a bit of engine
tuning so I get a feel for it and how the performance varies based on
this (I guess that will come with time too). I feel I may be damaging
my engine without doing this properly, but I guess that is always a
beginners mistake when you have limited information at hand about what
to properly look for.

Talking smoke trails, I noticed when I pulled on full throttle I get an
initial burst of smoke as the car accelerates. At higher speed that
trail goes down to minimal. Is that right?

Thanks in advance

Dean

[DanTXD]

"crabbdean" <crabbd@tabcorp.com.au> wrote in message
news:1154326167.836043.137180@s13g2000cwa.googlegr oups.com...
>
> "Doc" wrote:
>
>> HSN is adjusted properly when you get good top speed, a nice smoke trail
>> at
>> WOT and temps between 240*-300*F.
>>
>
> Thanks Doc, that's really helpful. I hope the wording of my question
> didn't come across as not trusting your information, it was just the
> way I (badly) worded it.
>
> The temps provided above... I found my car going over this range the
> other day, up to (and over) 250 deg cel. I'm wondering if the temp
> varies based on engine size? Mine is a .21, does that make a
> difference? Does the high temp suggest I'm running too lean?

I think you'll find it was 250f - I'm pretty sure it would be dead if it
went to 250c - thats like, what, 500-600f? What engine specifically as we
taking about and what is it running in? Some like to run hot (usually high
performance race spec lumps - RB WS7 II and the like). Once you've ran a
few, you'll start to not use the temp gauge, you'll get used to the sound
and the feel (performance wise) and you'll know when it's dialled in nicely.

> I really want to get out with my car and do quite a bit of engine
> tuning so I get a feel for it and how the performance varies based on
> this (I guess that will come with time too). I feel I may be damaging
> my engine without doing this properly, but I guess that is always a
> beginners mistake when you have limited information at hand about what
> to properly look for.

Well to be fair, I've over-leaned engines many a times, as long as you don't
just keep driving it and adjust it after it's complained you'll be alright,
you might reduce it's life by a bit, but I usually get bored and change
engines before this has ever mattered hehe :-)

> Talking smoke trails, I noticed when I pulled on full throttle I get an
> initial burst of smoke as the car accelerates. At higher speed that
> trail goes down to minimal. Is that right?

Yea that sounds about right, probably means you can lean your LSN another
tiny touch, but if it's taking off ok anyway, leave it. Personally, my Sav
has a slightly over rich bottom end as a kind of primitive launch control -
if I dial it in perfect it spends it's day flipping over with wheelies :-).
The advantage of course of this as well is I'm probably saving my rear diff
a lot of pain.

> Thanks in advance

No probs, HTH.

> Dean
>

--
Dan - on Laptop

[\Doc\]

"DanTXD" <me@privacy.net> wrote in message
news:4j673fF6ge14U1@individual.net...
> Been a while since we had some good banter going on in here isn't it :-)
> Got an opinion on STS motors? My K4.6 swallowed a lot of sand not long
> ago and I'm thinking i might need a change soon.... STS .28 appears to be
> cheap and powerful.
>
> --
> Dan - on Laptop

On paper they look good. Real good. Unfortunately they're a bit of a
bugger to purchase and get parts for on this side of the pond; they seem to
be much more prolific over in the UK and Oz. They're rated around 3.5 HP
aren't they? Have you looked at the Axial and SureFire .32's? They
definitely have my attention.............

Doc

[\Doc\]

"crabbdean" <crabbd@tabcorp.com.au> wrote in message
news:1154326167.836043.137180@s13g2000cwa.googlegr oups.com...
>
> "Doc" wrote:
>
>> HSN is adjusted properly when you get good top speed, a nice smoke trail
>> at
>> WOT and temps between 240*-300*F.
>>
>
> Thanks Doc, that's really helpful. I hope the wording of my question
> didn't come across as not trusting your information, it was just the
> way I (badly) worded it.

Not at all my friend!

> The temps provided above... I found my car going over this range the
> other day, up to (and over) 250 deg cel. I'm wondering if the temp
> varies based on engine size? Mine is a .21, does that make a
> difference? Does the high temp suggest I'm running too lean?

That's 482* F!! Like Dan has already suggested, recheck your guage and make
sure it's reading celcius and not F. If it was 250F you're doing ok; if it
was 250*C start looking for a new motor. I've only seen one motor run even
close to that temp without immediately dying and that was a Wasp .18 that
was running 410*F-ish. It blew it's little guts out all over my yard within
a few minutes at this temp. Anything above 300*F (149*C) indicates that the
HSN is too lean.

Temps are pretty consistent across the board of engine sizes, from .12 to
..32. Just about everything is happiest between 240*-300* F. Some of the
Italian racing mills will run in the 350-375's all day long, but they cost
more than the vehicle they're in! I have found that a nitro mill will
overheat long before it's reached it's performance potential, so if you tune
solely based on performance and smoke trail and ignore temp altogether
you're likely gunna be running her on the hot side.

FWIW, I have a .25 in my Savage with around 15 gallons of fuel thru it (yes,
15!). It runs like brand new and shows no signs of giving up the ghost
anytime soon. She has always been run 275-300*F on O'Donnell's 20% Race
Blend with OS A3 (fall and winter) and #8 (spring and summer) and had Marvel
Mystery Oil squirted down the carb as after-run oil after each session.
These little motors will run forever if you take care of them correctly and
pay close attention to tuning and temp.

<Dan, I know you're reading this...................and to you I
say.................I might be a bit anal with my nitro stuff, but who's
engine has more fuel run thru it and is still running strong and whose if
full of sand and in need of replacement! :-) >

> I really want to get out with my car and do quite a bit of engine
> tuning so I get a feel for it and how the performance varies based on
> this (I guess that will come with time too). I feel I may be damaging
> my engine without doing this properly, but I guess that is always a
> beginners mistake when you have limited information at hand about what
> to properly look for.

The first one is always a bugger to get a feel for. I killed a motor <poor
little thing> before I got good at tuning. I started in this hobby all by
myself, just like you. I didn't find this group until after I had started
to get a feel for it. I know how you feel! Just start rich and SLOWLY lean
the HSN out until the performance and temps are within acceptable ranges.
Ask lots of questions on here; there are some very knowledgeable folks who
are willing to give their time and advice. I'm very anal with my tuning,
running, cleaning and maintenance; others are quite the opposite. Somewhere
in-between the two is probably the best!

> Talking smoke trails, I noticed when I pulled on full throttle I get an
> initial burst of smoke as the car accelerates. At higher speed that
> trail goes down to minimal. Is that right?

Yup. A healthy puff off-idle is just fine; as long as you can see
blue/white at WOT and max speed you're doing allright.

Doc

[DanTXD]

""Doc"" <nospam@noway.com> wrote in message
news:3OWdnQsJcO9n_1PZnZ2dnUVZ_oSdnZ2d@adelphia.com ...
>
> "DanTXD" <me@privacy.net> wrote in message
> news:4j673fF6ge14U1@individual.net...
>> Been a while since we had some good banter going on in here isn't it :-)
>> Got an opinion on STS motors? My K4.6 swallowed a lot of sand not long
>> ago and I'm thinking i might need a change soon.... STS .28 appears to be
>> cheap and powerful.
>>
>> --
>> Dan - on Laptop
>
> On paper they look good. Real good. Unfortunately they're a bit of a
> bugger to purchase and get parts for on this side of the pond; they seem
> to be much more prolific over in the UK and Oz. They're rated around 3.5
> HP aren't they? Have you looked at the Axial and SureFire .32's? They
> definitely have my attention.............
>

They're the opposite over here, can't get Axial and SureFire bits, but I can
get STS bits everywhere :-) Definately one to consider for me then....
Hmmmm :-)

--
Dan - on his PC

[DanTXD]

""Doc"" <nospam@noway.com> wrote in message
news:V8ydne7JxfGR9FPZnZ2dnUVZ_vKdnZ2d@adelphia.com ...
>
>
> FWIW, I have a .25 in my Savage with around 15 gallons of fuel thru it
> (yes, 15!). It runs like brand new and shows no signs of giving up the
> ghost anytime soon. She has always been run 275-300*F on O'Donnell's 20%
> Race Blend with OS A3 (fall and winter) and #8 (spring and summer) and had
> Marvel Mystery Oil squirted down the carb as after-run oil after each
> session. These little motors will run forever if you take care of them
> correctly and pay close attention to tuning and temp.
>
> <Dan, I know you're reading this...................and to you I
> say.................I might be a bit anal with my nitro stuff, but who's
> engine has more fuel run thru it and is still running strong and whose if
> full of sand and in need of replacement! :-) >
>

You're of course right :-) But to be fair, it only got sand in it because
the air filter fell off and I didn't notice hehehe :-) For long life
definately follow Doc's advice - for the lazy persons way and *possibly*
faster running till they die - my way works for me.

--
Dan - on his PC

[crabbdean]

Thanks Dan and Doc for you advice. I find it sad that this info is so
hard to come by, so I'm really appreciating your advice. In the
perfect world, every car should come with a manual about tips and
tricks for maintenance and tuning. Even when I asked at the store
about when I bought it they only gave information if you specifically
prompted them for it, even then they weren't too forthcoming. I mean,
how am I meant to ask a question about something if I don't know what I
even meant to be asking for!!!

Anyway.... I bought the car but my brother-in-law and I are kind of
doing it together as a hobby, although I'll be doing all the
maintenance. I'm pretty anal as well and like the tinkering/repairing
part of it as much as the driving part ... so I think I'd prefer to run
it properly, and maintain it properly.

>>Temps are pretty consistent across the board of engine sizes, from .12 to
>> .32. Just about everything is happiest between 240*-300* F.

Now I'm pretty sure the temp guage was reading in deg cel. I even saw
it climb up to 350 deg cel. When I saw that I started freaking out!!
I let it cool down after that. But it makes me think the engine would
start melting about then. I wonder if the guage is reading wrong, or
is actually showing F instead of oC, even though is says oC.

Dean

[crabbdean]

Sorry, forgot to add, this is the specs on my car, including the engine
size etc.

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLMD1&P=7

Dean

[M78Ultra]

Been lookin at the STS pro 6 port..but I have yet to see any RPM range
listed...

"DanTXD" <me@privacy.net> wrote in message
news:4j7co2F6mqu3U1@individual.net...
> ""Doc"" <nospam@noway.com> wrote in message
> news:3OWdnQsJcO9n_1PZnZ2dnUVZ_oSdnZ2d@adelphia.com ...
> >
> > "DanTXD" <me@privacy.net> wrote in message
> > news:4j673fF6ge14U1@individual.net...
> >> Been a while since we had some good banter going on in here isn't it
:-)
> >> Got an opinion on STS motors? My K4.6 swallowed a lot of sand not long
> >> ago and I'm thinking i might need a change soon.... STS .28 appears to
be
> >> cheap and powerful.
> >>
> >> --
> >> Dan - on Laptop
> >
> > On paper they look good. Real good. Unfortunately they're a bit of a
> > bugger to purchase and get parts for on this side of the pond; they seem
> > to be much more prolific over in the UK and Oz. They're rated around
3.5
> > HP aren't they? Have you looked at the Axial and SureFire .32's? They
> > definitely have my attention.............
> >
>
> They're the opposite over here, can't get Axial and SureFire bits, but I
can
> get STS bits everywhere :-) Definately one to consider for me then....
> Hmmmm :-)
>
> --
> Dan - on his PC
>
>

[DanTXD]

"crabbdean" <crabbd@tabcorp.com.au> wrote in message
news:1154397778.533074.230510@i3g2000cwc.googlegro ups.com...
>
> Sorry, forgot to add, this is the specs on my car, including the engine
> size etc.
>
> http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLMD1&P=7
>
> Dean
>

I'd take a guess that that's running your basic Force .21 engine, as that's
what most RTR buggys, from companies that don't make engines run - also I
know the GV Mammoth here came with a Force .25. They're not bad engines per
say, tend to be easy to tune, but a little limp powerwise, and of the 3 or 4
i've known, 2 have blown up (nothing to do with me though!).

With buggys such as this brand (I had a Protech myself) you'll find it's
probably a re-badged something else (for example the protech was a Ofna
MBX). This is by no means a bad thing, in fact it can be very useful for
finding spares:-)

--
Dan - on his PC

[DanTXD]

"crabbdean" <crabbd@tabcorp.com.au> wrote in message
news:1154392758.381647.161990@b28g2000cwb.googlegr oups.com...
>
>
> Anyway.... I bought the car but my brother-in-law and I are kind of
> doing it together as a hobby, although I'll be doing all the
> maintenance. I'm pretty anal as well and like the tinkering/repairing
> part of it as much as the driving part ... so I think I'd prefer to run
> it properly, and maintain it properly.
>

Yea Doc's way is the best way to learn no doubt, I'm just a speed freak.
Off out to ride my motorbike now :-)

--
Dan - on his PC

[DanTXD]

"DanTXD" <me@privacy.net> wrote in message
news:4j8sulF56jvlU1@individual.net...
> "crabbdean" <crabbd@tabcorp.com.au> wrote in message
> news:1154397778.533074.230510@i3g2000cwc.googlegro ups.com...
>>
>> Sorry, forgot to add, this is the specs on my car, including the engine
>> size etc.
>>
>> http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXLMD1&P=7
>>
>> Dean
>>
>

<edit> I read it as GV - but it's not is it it's GS - someone else here had
a GV....

Anyway - It may still be a Force engine, but I can't be as sure as I was
when I thought it was a GV. I don't really know anything about GS - I'm not
sure we really get them over here.

--
Dan - on his PC