Boost and egt ?

[Mad Bomber]

What is the best temp to wait for shut down on a preturbo guage? Also boost guage falls to 0 if I'm not accelerating. I can get about 18 # at WOT

 

[Double 6]

You need to let temp. get down to 300 before shutdown otherwise you will coke up the turbo bearings.

 

[Cummins Corvette]

I wait until 350. If I wait until 300 I will be sitting there for at least 20 minutes most of the time (no exaggeration here). It takes about 3 to 5 minutes to get to 350 unless I was just putting around.

 

[DAWG-1]

Hi Eric,

Good to hear you got your gauges installed. I have allways waited until it drops below 300* before shut down. Sam

 

[illflem]

Since most gauges are only accurate in the middle of their range you need to figure out your own shut down temp as it will vary from gauge to gauge. Take your truck for a moderate drive then read the temp after a couple of minutes of idleing, the temp should be safe for shutting down, just remember that number. I'm with CAnderson, if I waited for 300° I'd be there all day. If your AC is on it will take much longer to cool down, this applies to the defrost mode as well since the AC is on, turn off the fan for a faster cool down.

 

[LSMITH]

300 is a good number for shutdown. If I am in a hurry I will shut it off at 325. 18 PSI at WOT is pretty normal, most trucks will spike up to 20 or 21 before the wastegate catches it, but come back down to 18 or 19 quickly and stay there.

 

[RJOL]

Boost

It's normal for you boost to drop to almost zero when not on the pedal. At about 60mph (stock truck) you should hold a steady 3-5lbs boost. If you don't see that, check all your fittings for a leak. If there is just a tube connector at the guage, without any tiewrap, then use a small tiewrap to secure the tube there. This will also prevent the tube from blowing off, which is guarenteed to get your attention...

 

[SlyBones]

Another reason for synthetic oils. Higher flash point??



I wait to 350 for normal driving. 300 when towing so I know the turbo has gotten plenty of air and time.



Another reason for a PDR HX35 turbo from santa. All that extra airflow helps those temps come down quicker. At least it seems that way to me.



Although even before the turbo, I dont recall 300 taking too long on my truck. 250 if I sit and wait forever. this is in nutreal or park. In gear it wont drop below 350 no matter how long I sit at the light.

 

[SnoKing]

I think the important thing here is to let it idle for a few minutes when it has been working hard to circulate oil through the turbo to cool it down. EGT temp will come down alot faster than the temp of the metal in the tubro. Post Turbo EGT's would be better for watching cool down. Does anyone with two senders have input to how closely post tracks to pre turbo temps during cool down? SNOKING

 

[JohnE]

its not E<b>G</b>T, but the manifold and casting temps

Exhaust <b>Gas</b> Temperature is most important during the high load running of your engine. Once the load is off and the EGT's cool down, the engine is safe again, but maybe not your turbo.



The important factor in engine (turbo) shutdown is to have the turbo castings and exhaust manifold below a temperature threshold that causes oil coking. An accepted standard for conventional oils is 300&deg; F. EGT. Those with synthetics are good for more, but I haven't seen levels in &quot;writing&quot;.



Obviously, a 1200&deg; F. EGT does not necessarily mean your turbo housing is near the same temperature, but it does if you hold your engine loaded for a significant time.



The reverse is also true. An idling diesel has a very cold exhaust. If you have been running under a load it will take time for the cooler exhaust gas to strip the heat from the hotter exhaust manifolds and turbo. Your thermocouple on the pyrometer is mounted in your exhaust manifold or turbo elbow. It picks up a lot of parasitic readings, especially at idle.



OK, many of you already know that. Some do not. Just thought it needed to be posted.



-John

 

[Mad Bomber]

thanx

Thank you one and all for info

 

[The patriot]

By the time I pull in the driveway, it's usually at 300, as long as I wasnt beating on it, or towing.



I dont know if it would be cost wise warranted, but when I owned my last car (turbo V-6 gasoline) there was some people who ran WATER COOLED turbo housings.

~Piers... are you listening?~



Eric

 

[JohnE]

WATER COOLED turbo housings?

The Cummins ISC and C+ gas (compressed natural gas version of 8. 3l engine) both use a coolant circulated turbo housing. The first problem in adapting that to our 5. 9's is the need to add a surge tank for proper coolant flow and block fill venting.



Hopefully ...



-John