Why monitor boost?

[scubieman]

Hoping someone can help me understand boost?. I understand it uses the exhaust pressure to spin turbo to push more air into the engine..But why have a gauge for it? Only thing I can assume is for the people that are running it down a truck or pulling 20k+ trailers. I plan on for now pulling about 10k or less. Chipping for MPG not for power. I am not running it down the track.. I guess you could say I will not be pushing it's limits in any shape.the only gauges I can think of of getting is pyro, trans temp, and soon rail/fuel PSI.Also what makes boost change? Putting pedal down? Pulling a trailer up steeper hill? I'm new at the boost so a guide for dummies would be great!

[Mopar1973Man]

But why have a gauge for it?

Basically more boost more fuel consumed!

Also what makes boost change?

Load... You can hold you throttle steady but climb a mild grade boost will increase. Boost also keeps the EGT's in check to when towing heavy loads more boost is normal which keeps the fuel burning clear (no smoke) and EGT's down to a managable level. Like running around empty I'm lucky if I see above 5 PSI cruising... But now load my truck with firewood or hitch up the Jayco behind me I might be lucky to see boost pressures below 10 PSI cruising. But out here where I'm at in Idaho there lots of rolling hills and grades so I've seen up to 32 PSI of boost climbing a 6% grade. Basically its nice to monitor that because you know you getting a good amount of air for the amount of fuel your supplying.

[scubieman]

But why monitor it? Do I have to worry ever about too much?

[Mopar1973Man]

Well at least for the 2nd Gen 24V series Hx35 turbo you start to worry about boost at 32-35 PSI... Then at about 40-50 PSI you start to worry about head gaskets. Then like in my little wild tale I lost a manifold bolt on a trip and lost all boost down to 8 PSI. Nice to have the gauge...

[scubieman]

So its like fuel pressure gauge... Dont really need but is nice for some troubleshooting while on the road?

[cajflynn]

I drive by boost and not mph. That is the best way to get mpg's. The more boost the more fuel you are using and vice versa.

[AH64ID]

But why monitor it? Do I have to worry ever about too much?

It's pretty much a work meter, more boost and your motor is doing more work... But really its not as important as some of the others, boost is fun to watch on a forced induction motor. Yes you can have too much, you don't want to push the 6.7 past 35-38 on the stock turbo/exhaust setup for fear of head-gasket issues caused by excessive back-pressure and limited flow. Boost is probably much more important on a 6.7 with a mild tune than rail pressure will ever be. Boost gauges are cheap, run one.

[clutch]

Boost involves boots and clamps that can sometimes leak. With a gauge you will notice what is not normal right away and be able to fix it before a hose might blow off and leave you sitting on the edge of the road. I have most things and a boost gauge is near the top of my list.

[AH64ID]

Boost involves boots and clamps that can sometimes leak. With a gauge you will notice what is not normal right away and be able to fix it before a hose might blow off and leave you sitting on the edge of the road. I have most things and a boost gauge is near the top of my list.

Very true. I would have never known my IC had a leak without a boost gauge. And without a pyro I would have melted something, even in stock trim.

[JOHNFAK]

But why monitor it? Do I have to worry ever about too much?

PLus its one of the more 'cooler' monitors. Someone says I was running 2400 rpm kinda sounds dull compared to 24 psi. But really - just like everyone else said its a really good monitor of whats happening in your engine. As EGT alone wont show you how much air your pushing and other problems or changes in the truck. I think boost and egt are really all I look at 90% of the time.

[dually]

Very true. I would have never known my IC had a leak without a boost gauge. And without a pyro I would have melted something, even in stock trim.

If you ever have a boost leak it will help. You can get a leak from several places.

[tonkatruck]

Like said above, I like running a boost gauge just in case the boost gets to high and cause a blown head gasket. It also shows if theres a leak somewheres, and show how the air filter is doing. Just this week i noticed the gauge seemed to have a slower climb in boost and only peaked at about 20-25 psi. My filter was clogged up from all the dirt roads I've been driving. Changed the filter and now back to 30-35 psi and a quicker build of boost. Guess its more of a maintenance thing for me

[dorkweed]

I drive by boost and not mph. That is the best way to get mpg's. The more boost the more fuel you are using and vice versa.

Don't know why I never bothered to check this thread out; but WOW!!! Mr. Flynn has just told the world how I get the mileage I do out of my '04.5!!!! Many folks take it as a "given" that the '04.5+ Dodge/Cummins get poor mileage. They don't if you know how to drive them.

Years ago, that's how the truckers did it. Drive by the boost gauge. It's smarter than you are........as long as it's working properly!!!

On my '04.5, I use the boost gauge and the RP (rail pressure) gauge to determine what speed I drive at. I'm a cheap buttocks, and anything I can do to get me more mileage out of a tank of fuel, I'll usually do. On trips I always leave early to give me plenty of time to get there...........if on a time frame. That way I don't have to go from a comfortable 68mph/2000rpm cruise; to a "white knuckle" 75-80mph slalom drive weaving in and out of traffic just to get there on time!!! I don't give a rats "dupa" if everyone on the road passes me. I had a cop tail gate me once on a "two lane". He couldn't pass me because of the on coming traffic for about 10-12 miles. I was doing 60 in the 55mph, and he was so close, that I couldn't see his headlights in my rear view mirror.

Anyhow; he found a spot to pass, and as he did, he paused along side of me and made a gesture to "pick up the pace". I gave him the "middle finger" and he buzzed off ahead of me. Go figure!!??? Nothing came of it. Had our situations been reversed; minus the hand gesture, I've no doubt I would've been pulled over.

[AH64ID]

Sometimes I wish I had a "boost control" instead of cruise control. Today I want to cruse at whatever 5psi will give me :-)The other factor is time, my time is worth something so I generally just cruise at a little faster pace but still reasonable. If I am going 500 miles and get 17 mpg at 75 mph (at 4.00 gal) it costs $117 and 6.7 hrs. If I am going 500 miles at get 19 mpg going 65 it costs $105 and 7.7 hrs, and depending on the circumstances my time may be worth more than $12/hr to me, other times it's not.

[diesel pap]

the 6.7 has a nice vgt turbo that does a great job. i blew a head gasket at 54k. it was because i had my smarty set to high and my right foot. the egts while towing never seem to get that high towing but the boost will get up there if your pulling hard. i run my truck when towing by the boost. i limit it to 32lb. once i reach that i back off. i hardly ever get 1100 egts. so to me on these 6.7s the boost is very important. of course this is just my opinion with little tests in a drive pressure gauge i rigged up after a hg repair.

[AH64ID]

Does the 6.7 run less boost than the 5.9 stock? The 04.5-07 5.9 runs up to 32 psi in OEM form.

[diesel pap]

i never saw a gauge on a stock truck to see for sure. i do know on my modded truck it will go way past that with a tuner fueling it. smarty has a boost fooler in it too. i do know after i blew a hg i put a make shift drive pressure gauge on the my truck. i found out that 24 lb of boost showed 24 lb of drive pressure 1 to 1 ratio. when the exhaust brake was on at about 2000 rpms the drive pressure showed 60 lb. at 32 lb of boost the drive pressure also showed about 60 lb. this is how i came up with my safe level (32 lb). the 6.7 vgt turbo is a good little fast spooling turbo but peaks out fast. this is the reason guys blows so many head gaskets. in my opinion the boost gauge is the most important on the 6.7 with the stock turbo. on the 5.9 the egt gauge is prob most important. i hope you can follow what a dumb ol man is saying

[AH64ID]

i never saw a gauge on a stock truck to see for sure. i do know on my modded truck it will go way past that with a tuner fueling it. smarty has a boost fooler in it too. i do know after i blew a hg i put a make shift drive pressure gauge on the my truck. i found out that 24 lb of boost showed 24 lb of drive pressure 1 to 1 ratio. when the exhaust brake was on at about 2000 rpms the drive pressure showed 60 lb. at 32 lb of boost the drive pressure also showed about 60 lb. this is how i came up with my safe level (32 lb). the 6.7 vgt turbo is a good little fast spooling turbo but peaks out fast. this is the reason guys blows so many head gaskets. in my opinion the boost gauge is the most important on the 6.7 with the stock turbo. on the 5.9 the egt gauge is prob most important. i hope you can follow what a dumb ol man is saying

That's a lot of DP, and also why I ditched my HE351. I think the Smarty runs more DP than the HS, but that's just what I have heard.

[diesel pap]

i dont really know how much diff between smarty and h&s. i know i blew my gasket on the smarty 14 me tune which was very good tune but like you said too much . i have the 22 me on it now. the later ones are still calmer. that 14 was power house though.

[pepsi71ocean]

t is more importaint to monitor boost in a 6.7, because of the cam. the exhaust stays closed longer, and rises cylinder pressure up much quicker, and thus leads to a higher frequency of head gaskets.If one was to simply throw in a towing cam this issue goes away.