iddling mixture speed, Vacuum in airbox

[Phil1988]

Hey,

got another question http://fsae.com/groupee_common/emoticons/icon_smile.gif Can someone tell what iddling mixture speed is usefull? Our idling mixture speed is now at round 2500 RPM and we got heat problems very fast.
How long is the time we can start the engine before a start of an dynamic event? When its more than 5 minutes we have real probs.

We got no experience because we are a completly new team.

Has anyone of you meassuered the vaccum in the airbox? I meassuered it last week and got 0.7 bar vacuum.

regards Phil

[Phil1988]

Hey,

got another question http://fsae.com/groupee_common/emoticons/icon_smile.gif Can someone tell what iddling mixture speed is usefull? Our idling mixture speed is now at round 2500 RPM and we got heat problems very fast.
How long is the time we can start the engine before a start of an dynamic event? When its more than 5 minutes we have real probs.

We got no experience because we are a completly new team.

Has anyone of you meassuered the vaccum in the airbox? I meassuered it last week and got 0.7 bar vacuum.

regards Phil

[exFSAE]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:
Our idling mixture speed is now at round 2500 RPM and we got heat problems very fast. </div></BLOCKQUOTE>

How on earth...? Even if you didn't have a fan installed (presumably you do) I'm amazed you can overheat within minutes - at idle.

[jlangholzj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:
Hey,

got another question http://fsae.com/groupee_common/emoticons/icon_smile.gif Can someone tell what iddling mixture speed is usefull? Our idling mixture speed is now at round 2500 RPM and we got heat problems very fast.
How long is the time we can start the engine before a start of an dynamic event? When its more than 5 minutes we have real probs.

We got no experience because we are a completly new team.

Has anyone of you meassuered the vaccum in the airbox? I meassuered it last week and got 0.7 bar vacuum.

regards Phil </div></BLOCKQUOTE>

I'd suggest checking that there's something not going on internally with the motor....for you to overheat that fast is very odd. No clue what motor you're running either but we run an 07 R6 with e85 and its typically a good 2-3 mins before our t-stat will open at idle and another 3-4 after that until the fans kick in. It almost sounds like something else is causing it to "overheat"....which also brings up what do you consider to be "overheating" ? for our system 200F is about operating temp...which is "hot" when tihnking in relative terms...but thats normal for the motor.

[TMichaels]

There must be something severely wrong. Are you already driving? I suppose not, because I cannot think of a failure mode (in FSAE applications) in which the engine overheats while idling, but not on the track.

What do you mean with 0.7 bar vacuum?
BTW: The SI unit (which should be mandatory for engineers) for pressure is Pascal.

[Mbirt]

Phil,

If you want us to help you, we need more information. Which engine, do you have a cooling fan, is the cooling system bled, is water coming out of the vent at the pressure cap, what is the cap pressure? Five minutes of idling to a tap water boil-over with no airflow through the radiator does not seam that far out of the realm of possibility.

[JWard]

I agree with Mbirt, especially a single with low mass, and possibly an underspecd rad. Bare in mind a lot of euro teams don't see the need for a fan unlike US teams. I've seen a ktm 525 heat up quickly because the waterjacket of the cylinder had a deposit on it.

To the OP: there's no need to be severely worried unless you're seeing large temps whilst driving - noise test is likely to be the longest period you'll run the engine for whilst sitting stationary (atleast at fsuk anyway).

Words of assurance aside, the guys in this forum will be able to help you diagnose this and work out why she's getting warm so quick - more info please!

[Wesley]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:
Hey,

got another question http://fsae.com/groupee_common/emoticons/icon_smile.gif Can someone tell what iddling mixture speed is usefull? Our idling mixture speed is now at round 2500 RPM and we got heat problems very fast.
How long is the time we can start the engine before a start of an dynamic event? When its more than 5 minutes we have real probs.

We got no experience because we are a completly new team.

Has anyone of you meassuered the vaccum in the airbox? I meassuered it last week and got 0.7 bar vacuum.

regards Phil </div></BLOCKQUOTE>

I would check your ignition timing, it sounds like you may be running it retarded. Also, the airbox shouldn't be pulling much of a vacuum unless it's a huge restriction. The carbs are attached directly to the head.

[Rex Chan]

I can tell you what idle engine speed is "normal" for us: 2000 (good - 2011) to 4000 (bad - 2009/10).

If your *cooling system* is overheating, then that's not good. But if that's what you designed it for... We run electric pump and thermo fan, so cooling at idle/revving with no car airflow isn't a problem (runs the battery down though). This works for us on testing (external battery) and comp (internal battery always on the charger).

You can start your engine up as late as you like at comp, so you can avoid overheating that way. But we like hot engines (over fuel economy), so warm ours up plenty.

PS. Unless you mean exhaust heat issues?

[jlangholzj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:

I would check your ignition timing, it sounds like you may be running it retarded. Also, the airbox shouldn't be pulling much of a vacuum unless it's a huge restriction. The carbs are attached directly to the head. </div></BLOCKQUOTE>

for us at 1400RPM we're at about 5-10kPa of vacuum. Just to support your point and to give some actual numbers.

[Phil1988]

Hey everybody,

thanks for the big response http://fsae.com/groupee_common/emoticons/icon_smile.gif great forum.

We use a Husaberg 570 single cylinder with 570ccm and about 70 Hp.

Our idling mixture speed is at about 3000 RPM. We still optimize our mapping. We have no dyno so we must improve it at driving with a lambda controller.

The engine has 110 °C after the cylinderhead approximatly after 10 min. We have a little fan with 120mm diameter from the motorcyle supplies.

The temperatur while driving is about 85°C

Regards Phil

[Mbirt]

Sounds like you're fine, Phil. Those temperatures are nothing to worry about.

I just looked up the 570--that's one different-looking single! If you rotated it 180 deg about the Z axis and used a jackshaft or internal gear work to reverse the sprocket's rotation, it might just fit Z's brown gokart.

[jlangholzj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:
Hey everybody,

thanks for the big response http://fsae.com/groupee_common/emoticons/icon_smile.gif great forum.

We use a Husaberg 570 single cylinder with 570ccm and about 70 Hp.

Our idling mixture speed is at about 3000 RPM. We still optimize our mapping. We have no dyno so we must improve it at driving with a lambda controller.

The engine has 110 °C after the cylinderhead approximatly after 10 min. We have a little fan with 120mm diameter from the motorcyle supplies.

The temperatur while driving is about 85°C

Regards Phil </div></BLOCKQUOTE>

typically whenever I get the motor first running, I'll get it started first (duur) and then get the idle set where I want it. After that I can set the mixture by revving the motor (VERY CAREFULLY i might add...be sure to watch that lambda!) and looking at lambda. Did i mention that you REALLY need to pay attention to lambda? This is your no-load line. That will give you a base from which you can get a pretty good idea what your map should look like. Typically I'll have to go back and get my idle dialed in after the no-load and some driving to get it right.

so:

1) idle
2) no load (you can then get a rough map from this)
3) idle
4) typically doing VERY light dyno pulls to get a feel for it and refine the map

what ECU/data logger are you running to actually look at the data? Also keep in mind that when you're looking at that data, make sure the driver has a very smooth throttle response. This will get you as close to the "steady state" as you possibly can. Otherwise if he's quickly opening and closing the throttle, chances are you're running into issues with accel/decel compensations.

If you don't have the resources for an engine brake or a dyno I'd suggest finding an open parking lot so you can moderately apply throttle in most of your gears. Get moving in first and then shift into third. That will move your whole load line up on the map and you can further tune it out.

As birt mentioned 110C is nothing to be scared of. As i mentioned earlier 100C is about operating for us (Yamaha R6) and 85C while driving tells me your radiator is working fine.

if you're overheating at idle, take a look at another (bigger) fan. Its all about fluid flow, whether it be water or air. If you look at our ETC's at idle, you can clearly see the drop when the fan turns on/off. For us I've got our fan coming on around 100C and shuts off at 85C

[Simon Dingle]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:

We use a Husaberg 570 single cylinder with 570ccm and about 70 Hp.

</div></BLOCKQUOTE>

Hi Phil,

That's a really interesting engine choice. Which team are you from, is your car going to be at FSUK next month? I'd love to see the installation.

Also, have you modified the engine at all to get 70bhp? I've read that the stock engine and ECU give the bike around 50bhp.

[Phil1988]

Hey guys,

Thanks to all the replies. The forum is great.
We're now looking for a second fan as a backup.

The stock engine has about 53hp. With little modifications like an sportexhaust and a modified mapping you get about 59 hp.

We modified the cylinder head a lot and integratet a new piston with a compression ratio of nearly 14 and special piston rings.

Regards

[Dunk Mckay]

Yup, as I've learnt over the last year or so this forum really does hold a wealth of information, you just have to be willing to find it, or failing that ask for it.

How did you source the engibes? If you can get it to run smoothly and bring a sweet car to comp it could be a good option, could be really nicely packaged.

Also as Simon asked, will you be attending FSUK this year, I'd love to have a look at what you've done.

[JWard]

Did you move to a different fuel? 14:1 on 99RON sounds ambitious!? Anyway, monsterous numbers for a NA restricted single, fair play!

I third Simon and Dunks questions - FSUK?

[Z]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mbirt:
I just looked up the 570 ...
it might just fit Z's brown gokart. </div></BLOCKQUOTE>
Mbirt,

I'd saw off the bottom half. Too much dead weight down there... http://fsae.com/groupee_common/emoticons/icon_smile.gif
~~~o0o~~~

Phil,

Remember that cold water wants to go down, while hot water and gas bubbles go up. Ideally the hot cylinder head is at the bottom, and the radiator and header tank at the top of the cooling circuit. Ie. thermo-siphon = good.

Radiator below cylinder head = trouble.
Header tank anywhere other than highest point = big trouble.
Engine exit pipe anywhere other than highest point of engine = big trouble.
Any flow paths going up-down like "W" = trouble.
Lots of rubber pipes going everywhere = trouble.
Thermostats = trouble.
Etc., etc.

Less is more. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Z

[Phil1988]

We're from the south of germany. Between Karlsruhe and Stuttgart. We only go to FSG and Italy... Uk would be too early http://fsae.com/groupee_common/emoticons/icon_wink.gif.The cars not running really fast and securehttp://fsae.com/groupee_common/emoticons/icon_frown.gif

We got great support from the little sportscar manufacturer and his motorsport section round stuttgart.

No we drive the 98 RON. I'm not the specialist at the engine things. To my knowledge the compression ratio at our engine could be up to 16 only considering the knocking of the engine because of the limited mass flow rate...

[Z]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Phil1988:
We're from the south of germany. Between Karlsruhe and Stuttgart. </div></BLOCKQUOTE>
Not too far from Mannheim, one time home of the legendary Lanz Bulldog. (http://en.wikipedia.org/wiki/Lanz_Bulldog)

(Easy starting...) (http://www.youtube.com/watch?v=TWSOuYSRII0&feature=related)

Now that was a good single!

Z

[Dunk Mckay]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mbirt:
I just looked up the 570--that's one different-looking single! If you rotated it 180 deg about the Z axis and used a jackshaft or internal gear work to reverse the sprocket's rotation, it might just fit Z's brown gokart. </div></BLOCKQUOTE>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Z:
I'd saw off the bottom half. Too much dead weight down there... </div></BLOCKQUOTE>

If you're gonna do that, chuck out the gears altogether and stick a CVT on that badboy while you're at it.

Phil, let us know how you get on. Sorry that we wont see you at Silverstone, but if I get very lucky I might make it to see you at FSG.

[Nicky]

I remember us having the same problem some time in the past. It turned out to be a problem with the water pump not being primed properly. Recommend you check that first.

Our engine temperature is nothing but the coolant temperature.