How do I test turbo boost? Do I need a scan tool? I'm sorry if my questions are "noobish" but I am new to the 6.5 club.

best bet would be a permanently mounted 0 to 15 psi boost gauge attached via a gauge pod to the a-pillar. but thats just me. :p::D

Sounds good to me. Is there a certain brand that best integrates? Is there a DIY on the procedure?

i bought a stewart warner gauge for ~$50 off summit racing. love it. individually numbered 0 to 15 with enough room on the dial that i can tell down to 1/2 a psi what i'm running for boost. get an EGT gauge as well. if your EGTs get too high you'll be runnign 0 boost as you'll cook your turbo(max pre-turbo is 1250*F).

If you really just want a peak at your boost levels, a higher end scanner will tell you what boost values your turbo is putting out. A boost guage is pretty worthless unless you truck is modified to build more boost than stock.

I don't think a boost guage is worthless without mods, I enjoy watching it climb and telling people I have a boost guage. Plus it just looks cool to additional guages!

Why in the heck didnt GM put a boost gauge in from the factory? :rolleyes:

A boost guage is pretty worthless unless you truck is modified to build more boost than stock.

You're right, on a stock truck you can do without it, but it does have it merits. Besides the "cool" factor (which I think is reason enough to get it!), it can help in diagnosing a problem.

Why in the heck didnt GM put a boost gauge in from the factory? :rolleyes:

Just like car companies have gotten away from numbers on temperature gauges - it just gives customers one more thing to look at and ultimately tell their dealer "There's something wrong with my boost - I should be getting 7lbs and I'm only getting 6.5lbs - you need to fix it under warranty". Well, something like that, anyway. :) Of course, the other train of thought is that putting in a boost gauge would make too much sense.

I thought the boost gauge gave me at least 50 hp:D. If you just want to cheaply test your boost you can buy a cheap gauge and plumb it in using brass fittings with your intake temp sensor. Not a perm solution but works in a pinch.

What kind of boost do these trucks build stock?

A boost guage is pretty worthless unless you truck is modified to build more boost than stock.

I respectfully, but totally disagree. Boost can tell you a lot of things about your truck. Example; let 5-10 psi out of each tire, then go drive it just like you normally do - hey, why is my boost higher than normal when cruising?

A buddy of mine was towing a boat to key west in his (totally stock)6.5 3500 dually and noticed that his boost was climbing a bit on level ground - after about 15 minutes he could feel the load getting harder to pull so we pulled over and when we got down to around 20 miles per hour one of the tires came apart on the trailer.

If you know how to use(and pay attention to it) a boost gauge can assist in several areas, not just tires/load. Plus they're just cool :D - why would anyone have a TD diesel and not have a boost gauge?:)

My boost gauge is essential. My intercooler pipes can only hold to 22 psi, if i don't back off before that I blow the pipes apart and then i don't get any boost. If you are going to change the boost control to a spring you better know what the boost and EGT's are before you blow the thing up. How are you going to know that if you don't have a boost gauge.

My boost gauge is essential. My intercooler pipes can only hold to 22 psi, if i don't back off before that I blow the pipes apart and then i don't get any boost. If you are going to change the boost control to a spring you better know what the boost and EGT's are before you blow the thing up. How are you going to know that if you don't have a boost gauge.

22PSI even with an IC that seem to be a bit much for a 6.5

I respectfully, but totally disagree. Boost can tell you a lot of things about your truck. Example; let 5-10 psi out of each tire, then go drive it just like you normally do - hey, why is my boost higher than normal when cruising?

A buddy of mine was towing a boat to key west in his (totally stock)6.5 3500 dually and noticed that his boost was climbing a bit on level ground - after about 15 minutes he could feel the load getting harder to pull so we pulled over and when we got down to around 20 miles per hour one of the tires came apart on the trailer.

If you know how to use(and pay attention to it) a boost gauge can assist in several areas, not just tires/load. Plus they're just cool :D - why would anyone have a TD diesel and not have a boost gauge?:)

Man, i see your point but thats kind of a stretch as justification for most people to spend the money on a boost guage. I suppose the typical person who has the desire to put a boost gauge on a stock truck will be attentitive to the inforamation the gauge provides, unlike the average person on the road who would ignore the check engine light flashing at them for miles upon miles.

My initial point was if someone were just wanting to check there boost quick, it could be easily done with a scan tool and they would not need to spend $50 bucks on a boost gauge if they dont want to.

You can get a gauge for $10 - $20 on eBay... Just look around. A 15 psi gauge will also work as a fuel pressure gauge for testing purposes.
You don't need anything fancy for testing things. A gauge, some tubing and a couple of fittings in the tool box for diagnostic purposes.

Just replaced wastegate actuator, it was not able to keep wastegate closed enough WOT. (EM chip, peak 1.0 bar, wot 0.8 bar) I think the "skin" is stretched... other wastegate actuator keeps boost fine :)

I had to look boost meter, temporarely vacuum meter, tdscan screen and the traffic during test run...

I couldnt even imagine not having a boost gauge. Even if you are trying to drive economically, you can monitor boost level and try to keep it low, thus requesting less fuel.

Man, i see your point but thats kind of a stretch as justification for most people to spend the money on a boost guage. I suppose the typical person who has the desire to put a boost gauge on a stock truck will be attentitive to the inforamation the gauge provides, unlike the average person on the road who would ignore the check engine light flashing at them for miles upon miles.

My initial point was if someone were just wanting to check there boost quick, it could be easily done with a scan tool and they would not need to spend $50 bucks on a boost gauge if they dont want to.

I say this humorously, but if someone buys a 6.5 and can't afford a boost gauge....they probably need to get rid of the truck. :)

How much does a scan tool cost?

These trucks aren't the most powerful diesels on the road and knowing what your turbo is doing(or not doing) is a must. As far as my justification being a stretch, that was just one reason. What about when someone adds a turbo master. How will they adjust it? When I installed my homemade TM it took me weeks to get it 'dialed in'...just when I thought I had it right, I hooked my equipment trailer and tractor to it, more adjustment. I guess if you knew someone that didn't mind you borrowing a scan tool...often, you could always go that route.

I think it was Diesel Pro, when I first joined - one of the first things he suggested was to install a boost gauge.

I say this humorously, but if someone buys a 6.5 and can't afford a boost gauge....they probably need to get rid of the truck. :)

How much does a scan tool cost?

These trucks aren't the most powerful diesels on the road and knowing what your turbo is doing(or not doing) is a must. As far as my justification being a stretch, that was just one reason. What about when someone adds a turbo master. How will they adjust it? When I installed my homemade TM it took me weeks to get it 'dialed in'...just when I thought I had it right, I hooked my equipment trailer and tractor to it, more adjustment. I guess if you knew someone that didn't mind you borrowing a scan tool...often, you could always go that route.

I think it was Diesel Pro, when I first joined - one of the first things he suggested was to install a boost gauge.

When someone adds a turbo master there truck is no longer stock, i would tell anyone who has installed a turbo master or anything that changed boost levels to install a boost gauge.

The person who started this thread asked what was needed to test boost, and also asked if a scan tool was necessary. There question was simple and my reply was pretty simple, if you just want a quick look, a good scan tool will tell you what kind of boost you are building, and ill bet if i had re worded my comment about boost gauges being worthless on stock trucks this thread would have had about half the replys. In my opinion stock boost levels are not worth monitoring, if your truck is 100% stock you shouldnt even be taking your eyes off the temp gauge long enough to even check a boost gauge:p:, besides do they even make a 0-7psi gauge ?:rolleyes:

Is gauge cheaper than a scan tool? Yes, i currently have $800 invested in my snap-on scanner and will probably spend more money on it of they still offer updates for my model in a couple years. Check the pinned up scan-tool/ lend a hand thread and you just may find someone in your area who would be willing to plug a truck in for pretty much nothing and has bud light on tap at home like i do, thats cheaper than buying a gauge or a scan tool.

Well, that's what I like about this place - we can respectfully agree to disagree on things.

When I installed a boost gauge on my 'stock' truck (as recommended by someone on DP) the first thing I noticed was that it was a great idea to monitor my 'stock' boost levels as they were almost non existent.

You can run a TM without a boost gauge..(Not recomended) Heath provides you with a stock setting.
A few guys here have done it.
This does not apply to "Homemade" TM.......Heaths unit is calibrated from the spring length......I believe it's 2 1/2 inches......again "AT YOUR OWN RISK"

Well, that's what I like about this place - we can respectfully agree to disagree on things.

When I installed a boost gauge on my 'stock' truck (as recommended by someone on DP) the first thing I noticed was that it was a great idea to monitor my 'stock' boost levels as they were almost non existent.

OK, i will give you that a on a DB2 fed truck there is no other way to tell how much boost is being made unless you put in a gauge.What is stock boost for a DB2 pump truck? something like 4psi? But on the 94 up trucks with computers, high or low boost levels will trigger a DTC. Im not trying to tell anyone to not buy a boost gauge, just trying to say its not the only way to get an idea of how much boost your truck is producing with the 94 up trucks.

But on the 94 up trucks with computers, high or low boost levels will trigger a DTC.
So my '97 would post a DTC if boost was too low/high? Would it also trigger a CEL/SES on the dash or just store the DTC to memory?

So my '97 would post a DTC if boost was too low/high? Would it also trigger a CEL/SES on the dash or just store the DTC to memory?
It may but that is kind of like waiting for the oil pressure light to come on to tell you to check the oil. You may get away with it for a while but in the long run it can't be good for the engine!

So my '97 would post a DTC if boost was too low/high? Would it also trigger a CEL/SES on the dash or just store the DTC to memory?


Yes. Your engine light will be on.

Yes. Your engine light will be on.
That is only assuming the sensor WORKS AND it knows when the boost is too high! From what i gather off this site egt's are the only way to know exactly when boost gets too high.

That is only assuming the sensor WORKS AND it knows when the boost is too high! From what i gather off this site egt's are the only way to know exactly when boost gets too high.

Im not overly familiar with the wastegate solenoid, but i believe since it measures voltage, a faulty sensor, or an unhooked sensor should produce a code for low or high voltage, much the same as a high boost or low boost code. Exhaust Gas Temperatures are not an accurate way to measure boost because even with say 20psi of boost, if there is no additional fuel to burn the exhaust gas temperature will not rise significantly.

Exhaust Gas Temperatures are not an accurate way to measure boost because even with say 20psi of boost, if there is no additional fuel to burn the exhaust gas temperature will not rise significantly

I've been wrong before but - Lean mixture means HOT.
Please educate me if I'm way off here!

I am by no means an expert but I understand it that:

Without an increase in cooled intake air, more fuel = hotter combustion = high EGT

Or increased intake heat due to no I/C, inefficient turbo, etc = increased EGT

Lean mixture means HOT.

:exactly: :agreed:

Maybe im still in the wrong here, BUT, seeing as how a diesel engine fires on compression and not spark....... If your air to fuel ratio was that unfavorable the truck would just flat out not run. Lean mixture/overly advanced timing in a gas motor= spark knock. How can one obtain spark knock in an engine that has no spark? Here is my understanding, as from reading, and having had to sort out a motor swap on a mechanical pumped truck.......... The less the fuel the lower the EGT. Less exhaust back pressure= lower exhaust gas temp. So perhaps even if a diesel engine experiences a "lean condition" the combustion chamber temperature is higher than it should be, but in my experience, less fuel mean lower EGTs, regardless of boost levels. I would love for someone with more experience/intelligence to explain this better than me. Perhaps im wrong, if i am mis interpreting my personal experience i would very much like for someone to correct me and explain to me why im wrong.

In my opinion there should be a boost guage installed on every turbo diesel vehicle. Its not just worrying about to much boost but to little also can cause problems over the long term.

You can not run a diesel "lean". "Lean" is a gas engine termonology. A diesel engine is controlled by fuel not air. When you increase the throttle you are giving the engine more fuel. When you decrease the throttle you are reducing the amount of fuel. You can over fuel a diesel by giving too much fuel, but they won't run or not for long. So, no you can not run a diesel lean.

In my opinion there should be a boost guage installed on every turbo diesel vehicle. Its not just worrying about to much boost but to little also can cause problems over the long term.
Which is exactly why the computer controlled vehicles will set off a DTC for out of spec boost levels.

You can not run a diesel "lean". "Lean" is a gas engine termonology. A diesel engine is controlled by fuel not air. When you increase the throttle you are giving the engine more fuel. When you decrease the throttle you are reducing the amount of fuel. You can over fuel a diesel by giving too much fuel, but they won't run or not for long. So, no you can not run a diesel lean. :agreed: But if someone has differing opinions/facts, we can sure continue to hi-jack this thread in the name of education;)

[QUOTE=odlaw;2919540]I say this humorously, but if someone buys a 6.5 and can't afford a boost gauge....they probably need to get rid of the truck. :)

I think I resent that statement:mad::D I have spent soooo much on this truck since I bought it i am quickly going broke, but, I WILL NOT part the truck. it is my first diesel & I love it:):D:thumb: