F4i EGT's

[Mike Claffey]

Lately I have been wondering what is a dangerous EGT for our F4i. We see above 6-700 degreesC at the exhaust ports while chugging along at places like 20-40% throttle and I'm just trying to get a good idea as to when to say ohh shit and back it off. Right now that happens around 800-850 degreesC. Am I being to conservative here? (Or to rough?)

What has your experiences told you when it comes to the limits of the F4i?

thanks,

Mike
UWAM

[Mike Claffey]

Lately I have been wondering what is a dangerous EGT for our F4i. We see above 6-700 degreesC at the exhaust ports while chugging along at places like 20-40% throttle and I'm just trying to get a good idea as to when to say ohh shit and back it off. Right now that happens around 800-850 degreesC. Am I being to conservative here? (Or to rough?)

What has your experiences told you when it comes to the limits of the F4i?

thanks,

Mike
UWAM

[BeaverGuy]

Last year with our Kawasaki motor we had EGTs up to 1500-1600 degreesF at full throttle and 12,000 RPM taken just outside the ports. We didn't have any problems.

[Erich Ohlde]

If u melt ur head gasket then u were running a lil too hot.

we somehow manage to get our header to run red hot when we tool around in a parking lot. definately looks cool at night. not sure what the temps are but they are enough to turn stainless steel a perfect gold color like what happens after you weld it. and thats through the header wrap

[DaveC]

High EGT temps can cause cumulative damage. The shorter the lifespan you require of the motor, the more liberal you can be with EGT limits. It also depends how long the EGTS are up there. On my Rally car, which I DO NOT want to have to rebuild the motor very often (at all), 900 C is a good short term limit. If it gets up that high for a second or two on an uphill straight, thats OK, but I'd like it to be at 775 C or so normally.

[Perry Harrington]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by jayhawk_electrical:
If u melt ur head gasket then u were running a lil too hot.

we somehow manage to get our header to run red hot when we tool around in a parking lot. definately looks cool at night. not sure what the temps are but they are enough to turn stainless steel a perfect gold color like what happens after you weld it. and thats through the header wrap </div></BLOCKQUOTE>

I've seen this on Yamaha WR450F engines. It can be caused by a few things. Rich with late timing. Late timing period. And exhaust cam timing that is way too early.

--Perry

[Mike Claffey]

Does anyone go past 55 degrees advance on the f4i?

Regards,

Mike
UWAM

[Erich Ohlde]

holy crap! 55 degree's! We don't take it past 45 although we have proven that an F4/3(not sure which) can run 85 degrees of iginition timing. although they make like 40 hp and overheat idleing

[Mike Claffey]

Erich: 85 im surprised, even low load that doesnt sound to good. Previous engine guys at our team have taken an f4 up to ~72 and things went bang pritty quickly. I realise that timing is just one factor in a complex system so I wouldn't mind knowing if any teams have made things work well with lots of advance.

Another question, does anyone run with 4 pressure transducers in their f4i's head? It seems like a really good way to know whats going on inside there. I'm trying to think of a way to measure/listen for knocking when the car is in an insulated test cell - any ideas?

Cheers,

Mike
UWAM

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Claffey:
I'm trying to think of a way to measure/listen for knocking when the car is in an insulated test cell - any ideas?
UWAM </div></BLOCKQUOTE>

Dyno knock monitors basically consist of a microphone or transducer clamped to the cylinder head with an adjustable band-pass filter and then a speaker. Set up right you only hear a click when it's a real knock. Set up wrong and you can miss the knock events...

An electronics student could probably build something quite easily.
Ian

[Erich Ohlde]

Lemme tell ya. We didn't mean to do 85 degrees. It was back on the '99 team. They did something funky and they thought they were only running 42 degrees of timing. Ran through competition (didn't finish endurance), all summer autocrossing then the 2000 team figured out that the 99 team was stupid. Good times tho

[Patrick Cahill]

So how are these guys arriving at timing values anyway?

[Mike Claffey]

950 was reached when steady stating the dyno at some points today. Didn't sit there for too long but the numbers were really good. BSFC and torque were good. I'm starting to reasses where I should put the limit, as I hear some of the turbo teams run past 1100 C. Anyone else willing to chime in on how high they let their egt's go.

Regards,

Mike
UWAM

[CMURacing - Prometheus]

hot enough to melt the aluminum tip off of our yoshimura muffler on the dyno...

[kovacs]

So how are these guys arriving at timing values anyway?

work on the dyna, and in the car until you get good power numbers with no pre-ignition, and good car response. theres no set way to say at this rpm, MAP there should be this specific degrees advance.....you have to put endless hours in on the dyna.

[murpia]

Minimum advance for Best Torque or MBT is the usual technique to set advance.

Run at a steady-state rpm and MAP / throttle. Start off retarded and keep advancing the spark until you see a peak torque figure. That is your MBT advance at that mapping point.

Sometimes the engine will knock before you reach peak torque, in which case you are knock limited. Keep below the knock limit.

MBT and knock are both affected by air inlet temp, engine coolant temp and lambda. Make sure a) these are at realistic values on your dyno for your vehicle installation, and b) constant during the test. Sometimes hard to do, but necessary.

Ian

[Frank]

speaking of heat...

don't run a carbon muffler on a dyno, they need a lot of air passing over them

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Frank:
speaking of heat...

don't run a carbon muffler on a dyno, they need a lot of air passing over them </div></BLOCKQUOTE>
I will make a 4-year bump to second this notion. We didn't even run under load http://fsae.com/groupee_common/emoticons/icon_frown.gif

[JamesWolak]

500+ pulls on the dyno with a carbon muffler and never had a issue. Was it a two brothers one?

[Wesley]

We also have run red-hot headers several times (often through the ceramic coating) while putting around in skidpad, and melted aluminum shims at the muffler inlet.

I've heard numbers from 1300-1500ºF are reasonable rules of thumb, but that was for bigger V8's and not high-speed bike engines. That's not based on engineering data, just what works for some people.

At around 1650ºF oxygen sensors start to fry, so I wouldn't run for any length of time above that..

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JamesWolak:
500+ pulls on the dyno with a carbon muffler and never had a issue. Was it a two brothers one? </div></BLOCKQUOTE>
It was a donated Vance and Hines muffler. It is now discontinued, and never gave me a whole lot of confidence (the whole casing would pulse and swell). It got a little hot and cracked. I liked it, it weighed nothing.

[Grant Mahler]

The R1 Ti mufflers will crack/melt pretty quick if you run rich/retarded.

[Marshall.Hagen]

1350*F @ 8700, 42 lb-ft, 41* BTDC for MBT.

EGT's spike to ~1500 during part throttle, high advance areas of the map.

Superflow SF-901 Engine Dynamometer

[Drew Price]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Grant Mahler:
The R1 Ti mufflers will crack/melt pretty quick if you run rich/retarded. </div></BLOCKQUOTE>



.....and on rigid mounts (as opposed to vibration isolating).



Best,
Drew

[kapps]

We also saw over 1500*F on ours in places at the top of the revband. Headers glowing down to the collector. We made several dozen pulls and the engine came through like a champ. I was expecting bad things the first time I saw them get so high. We're running an SF-901 dyno with k-type thermocouples in each pipe about 1.5" from the head.
http://gallery.me.com/kapps/100024/IMG_0372/web.jpg?ver=12276772280002

[Wesley]

They can get hot sometimes.

http://www.youtube.com/watch?v=grCTYKpzFmM