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Lowering AFR to lower engine temp?

Started by Ronbo2, April 02, 2020, 08:50:44 PM

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Ronbo2

I have some questions on lowering my AFR settings to lower my engine temp.

BIKE 17 FREEWHEELER,107, HEAVY BREATHER, 22X CAM, CFR SLIP-ON, CAN TUNE from fuel moto, PV tuner

CURRENT SITUATION:
I feel I have my VE tables tuned in pretty well and now only get 2%-4% variations if I run a PV autune basic.  BUT now cruising at 70mph on 75 degree day my head temp runs about 10-15 degrees hotter (360) than it did before changing the VF tables.  Engine temp is around 320-330. Oil temp under 220.

MY THOUGHT IS
to lower the AFR table from 0.980 to 0.952 (3%) in the area I cruise at about 70% of the time (70mph, 2900 rpm, 40-55 map, 17-20 TPS), in order to lower my engine head temp.

MY QUESTIONS  ARE
- Is lowering my AFR better then raising my VE tables to lower the head temp?
- is 3% a big difference? (0.980 vs 0.952) ... should I go even a bit more?
- is there any negative side to tuning an engine a bit richer in these lower MAP and TPS areas?  I don't care about gas mileage, but don't want to loose any power, mess up my 02 sensors, etc. 
- does changing AFR affect other setting in the ECM?

guydoc77

I wonder more what your timing is in those area.

Ronbo2

Thanks for your input.  I'm a bit uncomfortable about changing timing because I don't have a good understanding of what the effects may be.  I've attached a photo of my front spark advance and am willing to play a bit if you have any suggestions.  My head temp spark adjust table shows a -1 to -3 when HT reach 356-360 at 40-50 MAP.

Would appreciate any suggestions!
Thanks,
Ron
[attach=0]

rigidthumper

Going from .980 ( 14.39 AFR) to .952 (13.98) results in less than 3% more fuel being sprayed, not enough to lower temps significantly. You could try adding a significant amount of fuel,(.920, ~13.5) but be aware since you are increasing the leftover fuel in the pipe, you are also increasing the temp @ the catalytic converter.

Ignorance is bliss, and accuracy expensive. How much of either can you afford?

mayor

I haven't tuned or ridden an M8 so I could be giving you bad advice, but it looks to me like the timing table are somewhat retarded.  Too little timing will create heat.  If it were mine, I would try adding 2 degrees of timing in the 1750-3000 rpm columns in the 40-80 kPa columns and see how that affects heat. 
warning, this poster suffers from bizarre delusions

Coyote

Does it not seem messed up to have head temps that high with oil temp that low?

rigidthumper

M8 cylinder head temps read higher than TC head temps because of the sensor location. Oil temps are more important to me.
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

Coyote

Quote from: rigidthumper on April 04, 2020, 11:13:12 AM
M8 cylinder head temps read higher than TC head temps because of the sensor location. Oil temps are more important to me.

:up:  Yeah the oil temp is plenty cool.

Ronbo2

Quote from: rigidthumper on April 04, 2020, 07:33:59 AM
Going from .980 ( 14.39 AFR) to .952 (13.98) results in less than 3% more fuel being sprayed, not enough to lower temps significantly. You could try adding a significant amount of fuel,(.920, ~13.5) but be aware since you are increasing the leftover fuel in the pipe, you are also increasing the temp @ the catalytic converter.

Thanks for the input.  I'm going to lower to 13.98 just to see what happens. If it's significant I'll play around a bit and see what happens.  My spark advance drops by 1 each 10 degrees the head temp rises above 340.  Didn't even think about the cat, but right now the 'felt' heat isn't a real issue for me. 

Thanks again,
Ron

Ronbo2

Quote from: mayor on April 04, 2020, 07:52:43 AM
I haven't tuned or ridden an M8 so I could be giving you bad advice, but it looks to me like the timing table are somewhat retarded.  Too little timing will create heat.  If it were mine, I would try adding 2 degrees of timing in the 1750-3000 rpm columns in the 40-80 kPa columns and see how that affects heat.

Thanks, I'm going to give it try just for my education if nothing else.  I did notice that my spark advance head temp table does drop 1 degree for each 10 degrees my head temp goes up after 340.
Thanks again,
Ron

Ronbo2

Quote from: Coyote on April 04, 2020, 10:27:11 AM
Does it not seem messed up to have head temps that high with oil temp that low?

I was suspect of the oil temp as well but have done several checks over many different riding conditions with a digital thermometer as quickly as possible after stopping.  The oil temp does continue to slowly rise as it sits for 10 minutes which kind of makes sense as everything beings to equalize.  I do have an aux 6 tube jagg cooler on it along with the stock fan cooled oil cooler.  It use to run around 240 without it. 

Thanks

Ronbo2

Quote from: rigidthumper on April 04, 2020, 11:13:12 AM
M8 cylinder head temps read higher than TC head temps because of the sensor location. Oil temps are more important to me.

I agree... the oil temp is a big reassuring factor to me.  I have come to the conclusion that the biggest factor with the head and engine temp is the air flow.  I've noticed that with riding with the right 10-15 mph cross wind will bring the temps down a good 15 degrees, while adding the oil cooler only gave me about a 5 degree drop in engine temp even though the oil dropped over 15 degrees.

My main objective in trying to bring down the head temp is performance.  Looking at the different ECM tables it starts to really pull back spark etc after 343 degrees, so my goal is to see if I can somehow keep it under that when I'm just cruising around. 

Sunny Jim

Do you have lower fairings? Air flow is essential.
I run mine around 14.2 - 14.4 in cruise. I sit around 290 - 320 * on a 30*c day.
It's a Roadglide. I also have wards fans! They make a difference.

joe_lyons

I would suggest setting your minimum closed-loop lambda value to .956 and setting your closed loop area in to be at .958ish.  most of the time I see that the actual AFR is about a half a point leaner than what is commanded, sometimes due to the sensor location and other factors.  You may just highlight from 60 kPa and down and a couple degrees both front and rear ign timing and see what that does.  More often than not adding too much fuel goes the opposite direction for cooling the engine than what most people think.  Realistically enough though if your oil temps are staying in that range you're right there where you need to be, you would always like to see your oil temp stay just above boiling point of water.
Powerhouse Cycle & Dyno - Performance is our passion 816-425-4901

Ronbo2

Quote from: Sunny Jim on April 07, 2020, 06:27:39 AM
Do you have lower fairings? Air flow is essential.
I run mine around 14.2 - 14.4 in cruise. I sit around 290 - 320 * on a 30*c day.
It's a Roadglide. I also have wards fans! They make a difference.

No fairings, but I have noticed a 15 to 20 degree drop with a 15mph cross wind versus a tail wing so you're dead on about air flow.  When you say 290-320 is that engine temp or head temp... hoping it engine temp.  I thinking about fans but not sure how big of a difference they make after 50mph. My slow speed temps are relatively low, but I never been stuck in heavy traffic for an hour either.

Thanks, Ron

Ronbo2

Quote from: joe_lyons on April 07, 2020, 06:37:16 AM
I would suggest setting your minimum closed-loop lambda value to .956 and setting your closed loop area in to be at .958ish.  most of the time I see that the actual AFR is about a half a point leaner than what is commanded, sometimes due to the sensor location and other factors.  You may just highlight from 60 kPa and down and a couple degrees both front and rear ign timing and see what that does.  More often than not adding too much fuel goes the opposite direction for cooling the engine than what most people think.  Realistically enough though if your oil temps are staying in that range you're right there where you need to be, you would always like to see your oil temp stay just above boiling point of water.

I'm going to play around with this and maybe even learn something.  I just looked at several canned maps from dyno jet and fuel moto and so far they all use the identical minimum closed-loop lambda value of 1.014 and .981 max... would like to see if these are changed when a specific bike is dyno'd.  So much to learn.

At least everyone is saying my oil temp is ok which has given me some piece of mind.

Thanks again, Ron

aharp

You haven't mentioned what oil you run, curious on that
Speed costs money. How fast do you want to spend?

Ronbo2

Quote from: aharp on April 09, 2020, 03:32:26 AM
You haven't mentioned what oil you run, curious on that

Just the HD full syn.  I did just get the new larger oil filter put on but I don't expect to see any change temp wise.  I also have the 6 line aux jagg oil cooler and the stock cooler with fan.  I was a bit surprised to see how small the oil line used to cool the head was.  My oil goes through both coolers, then the heads.

aharp

Quote from: Ronbo2 on April 09, 2020, 09:35:52 PM

Just the HD full syn.  I did just get the new larger oil filter put on but I don't expect to see any change temp wise.  I also have the 6 line aux jagg oil cooler and the stock cooler with fan.  I was a bit surprised to see how small the oil line used to cool the head was.  My oil goes through both coolers, then the heads.

I am a fan of the 60wt Amsoil synthetic, although i havent done any testing to see if it lowers temps any.
Speed costs money. How fast do you want to spend?