no coolant 'lhm' as on Cadillac northstar and au falcon

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no coolant 'lhm' as on Cadillac northstar and au falcon

Postby barana » Sat Sep 13, 2014 10:36 am

was thinking this would be a very handy feature if you ran out of coolant or your waterpump carks it a couple of hundred kays from anywhere or if one is running late for work. like the above engines, the ecu would run in lowpower or cool(off stoich) mode so that you can limp home.iirc the northstar v8 runs one bank for a while then alternates to the other as to not overheat.I presume the falcon would run in 3cyl mode,alternating to the other three.
This would be a cool feature for 304/8 ,253's holden v6's and red/blue/black sixes.
Is it feasable?
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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby jenko » Sat Sep 13, 2014 1:21 pm

yes but you will still cook the engine with no coolant. Engines are very reliable till they run out of something.

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby barana » Sat Sep 13, 2014 5:31 pm

from what I recall from the report, I think i saw it maybe on youtube, that the northstar will alternate from one bank to the other for up to 100km. weather they used sensors to say sample oil temp, or due to testing they reconed 100km or was it miles? is about the limit of this low power mode. it would be more effective with a v engine i recon.I remember reading about pumping losses on engines, and a broad statement in this writeup was something to the effect of 'engines only need about 40hp for highway cruising' I think also with a coolant loss there would be a few litres of coolant sittng in the bottom of the block, albeit boiling but would still having a cooling effect for some km. lemme see if i can find the northstar info.
"Its alright for god, he doesnt drive a kingswood.Even the nuns only have toranas"-Ted Bullpit
Me:yeah,corse,God's a Holden man
Mate:whaaa?
Me:Psalm 83:15 so pursue them with your Tempest and terrify them with your Storm
A Holden & a pontiac

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby barana » Sat Sep 13, 2014 6:19 pm

www.tomorrowstechnician.com/northstar-v ... ry-carley/ Ok here it is. Not much detail
,but there's two interesting points.1.coolant lhm allows vehicle to run for 50 miles @50 mph without coolant by cycling the firing cyls , when each cylinder Is not firing it has just air pumping thru it thereby cooling it.
2. At the end of the article there is an interesting bit on the pcm setting being adjustable and viewable on the.climate control displays.. Pretty cool idea.
"Its alright for god, he doesnt drive a kingswood.Even the nuns only have toranas"-Ted Bullpit
Me:yeah,corse,God's a Holden man
Mate:whaaa?
Me:Psalm 83:15 so pursue them with your Tempest and terrify them with your Storm
A Holden & a pontiac

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby antus » Sun Sep 14, 2014 7:37 pm

Thinking about this, Im dubious how much gain there could be in that. Running half as many cylinders means the other half have to be burning twice the fuel to generate the same power. The same amount of cool air is going in, and exhaust temps will be higher in the cylinders that are doing the work. Thus when you swap which cylinders are doing the work they are starting at a higher temperature than if they all ran. Whats more although they are designed for heat cycle im not sure moving hot spots around the head is a great idea. I'd rather see the pcm with electronic throttle just limit the throttle opening depending on temp and set the CEL light, but of course then you might want to sink in the boot to get out of trouble and to hell with the engine (might be about to be hit by a truck etc). To my mind the gains would be small, if at all, and it sounds like marketing.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby barana » Sun Sep 14, 2014 8:07 pm

Reduced power.80km/h cruise requires little power. Around the 40hp mark. Also I think they cycle the pistons that ignite, kinda like hot potato. 50 miles is like 60kays. An when the engine gets too hot the info display says.shutdown now.Yes it sounds like marketing, but they would not risk 20,000 lawsuits for a feature that doesnt work.
"Its alright for god, he doesnt drive a kingswood.Even the nuns only have toranas"-Ted Bullpit
Me:yeah,corse,God's a Holden man
Mate:whaaa?
Me:Psalm 83:15 so pursue them with your Tempest and terrify them with your Storm
A Holden & a pontiac

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby antus » Sun Sep 14, 2014 8:36 pm

Yes. I question how much improved it is over regulating power with your right foot and with manual shutdown by watching the temp gauge while running on all cylinders with less load per cylinder. Although you would want to know where your dash temp sensor is, as if its away from the engine the engine could be significantly hotter than the meter on the dash.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby barana » Sun Sep 14, 2014 8:41 pm

Yes I have wondered how the ecu knows what is too hot for the engine, considering the sender would be high and dry the only idea I would have is it monitors oil temp and exhaust temp.
Much improved, id say, as constant burning in cyls will result in overheating quick, yet 5 seconds on (at a low power mode, such as slightly rich or lean with timing that would fit a low power producing profile)5 seconds off would give 5 seconds air cooling time.
"Its alright for god, he doesnt drive a kingswood.Even the nuns only have toranas"-Ted Bullpit
Me:yeah,corse,God's a Holden man
Mate:whaaa?
Me:Psalm 83:15 so pursue them with your Tempest and terrify them with your Storm
A Holden & a pontiac

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby jenko » Sun Sep 14, 2014 9:40 pm

in past expirience if the bottom radiator hose blows the engine is cooked before the temp gauge even registers that is with cast iron chev alloy would be even worse

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Re: no coolant 'lhm' as on Cadillac northstar and au falcon

Postby VL400 » Mon Sep 15, 2014 2:02 pm

Aside from having the same thoughts as others, its not possible on the '808 (VN/VP) ECU to do this as its batch fired injection so cannot turn off individual injectors.

Your other question on how the ECU knows what is too hot etc, the factory engineers would model the engine under various conditions and then setup the calibration to estimate temperature. They do this on LS1 engines to control ignition coil temperatures and then varying the dwell, there is no temperature sensor in the coil so based on vehicle speed, coolant temp, engine load and other factors the temperature is estimated. The charge temp calculation on our MAP engines is another example, there is no temperature sensor in the combustion chamber to measure the air temperature so a model was developed to estimate the influence of coolant temperature heating the air as it passes through the intake at various load and RPM points in addition to the manifold air temp sensor. Catalyst over temp another example.

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