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TM results and other observations/questions

bison

bison

Well-Known Member
Messages
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Location
Near Peace River-Alberta
On my 98,I got the TM build and took a testdrive.I am impressed! Its a complete diff truck now.Whoever came up with this idea needs a :grouphug:.

Cruising at 2000 rpm at 105 km nets a steady 3 psi and 400'ish EGT's,was about 700 before the TM,and no boost on the flat.
Climbing a couple of long 7% hills whips the boost to 8 and EGT,s rise to 800 and stay steady.
When i stomped on it,the boost went to 15 psi ( might need to back the spring off a bit) but the EGT's stayed at just under 1000 for the duration till i crested the hill and backed of the trottle.(bout 15 sec).Before the TM i got 4-5 psi at 1000 egt's on same hills cruising.

No codes or seslight triggered,no defueling either,she just keep pulling.Stock puter.

coolant Temps stay steady as a rock at 180 F.
I got a CTS in the rear of the pass side head as well,with a toggle switch in the cab to monitor eiher bank on the dash gauge. temps on both banks stay identical on all occasions.( longterm beliefs that the rear gets hotter than the front are not backed up by what i found sofar)?

I hooked up a line in the plugged air filter indicator port with a vac gauge in the cab before the TM test,to see how much vac the turbo would pull.
surprise surprise,there was zilch,zero,notting,not even at 15 psi boost( the gauge is accurate)I can suck it with my mouth up to the limmit.

Question: is no vac at all times pre turbo inlet normal?
If it is, then that brings me to the next question:
how in the world can the CDR ( not that i have one, i dont,I never believed in them) maintain a vac in the crankcase if there aint none at the T inlet elbow to start with???:dunno:
 
I think you will find you are using wrong instrument to measure with, due to volume of flow and large cross sectional area of measurement, you need a manometer or flow gage that measures like a manometer to read the vac, it's there rest assured.
 
Turbine Doc said:
I think you will find you are using wrong instrument to measure with, due to volume of flow and large cross sectional area of measurement, you need a manometer or flow gage that measures like a manometer to read the vac, it's there rest assured.
Click to expand...
howmuch vac is there supposed to be in the crankcase,if i cant read none cause of the reasons you stated, then IMO the CDR would have the same problem.IE not enough flow to make the diff,and just becomes a one way breather.Unless the airflow past the 90 degree angle to the tubo wheel installed CDR T inlet creates some suction there.Like blowing across the open end of a straw.Gawd, this gets confusing

The gauge i used is a sensitive 4" full sweep gauge commonly used on milking machines ,that will read in fractions of an hg.

You said in another post,that the stock filter was so restricted that it would trigger the airfilter indicator when you stepped on the trottle on your ATT equiped engine.the orifice on that thing aint much bigger than my gauge inlet.
At what boost level was that?
 
Good job on the home-built TM.

I've got the factory coolant sensor/gauge in its stock location & an aftermarket, mechanical sender/gauge in the opposite head's port - don't trust the factory setup precision enough to try compare the two. On the racecar, any temp difference btwn the front & back cylinders showed most when the cooling system was near its limits - when the rad exit temps were higher. Be interesting to see if you see any differences at your highest summer temps with the loaded stock trailer?

Did the filter minder trip as it's supposed to when the filter got more loaded & restrictive?

I measured vacuum btwn the air filter & turbo compressor inlet in the first couple weeks of driving my fresh engine to get some idea if my air cleaner setup flowed adequately. With stock chip boost levels (peak 8-9 psi), peak vacuum levels looked to be btwn 1-2 psi. Appeared to be a relatively small pressure difference before & after the filter. I'll measure this again as I go stepwise to higher boost/fuel on the stock GM-4 turbo, & again w/ the Holset. Should show if/when the current air cleaner becomes restrictive.

I'd really like also have a large, unrestrictive hot-wire mass airflow sensor in the air intake & be able to datalog actual airflow relative to rpm/boost & other parameters. One of my past gas turbo engine projects used an aftermarket hot-wire MAS along with datalogging. Going thru a run stepwise watching the parameters change in small time intervals was helpful in understanding what's going on.

Accurate MAS readings could be helpful in better understanding the flow differences in the various turbo's being run on the 6.5. This is interesting to me because diesels run such a wide variety of air/fuel ratios compared to gassers. Seeing what/if any power differences went with changes in boost/airflow at a given rpm & fuel rate. You could make better, more analytical judgements on what the ideal boost/airflow rate is for different conditions. How/when additional airflow adds power & how it impacts EGT etc.

If EFI Live has these datalogging & graphic display/playback functions, that makes me a bit envious of the DMax guys using it.
 
Perhaps there would only be vacuum if the air intake was inadequate or clogged. Otherwise just flow.

Sucking out of a coffee stirrer - vacuum, inadequate CFM allowed by

Sucking out of a large shop-vac hose (patooie) - no vacuum, adequate CFM allowed

Perhaps?
 
It's a function of airflow, Bison, but it's an open system... the 'pull' of air (and it's there, no doubts) goes into the turbo. But... it goes in from the easiest possible area, just like water finding its' own level.

If the turbo can pull air easily from the filter, then it won't pull against the (closed) gauge. That's why the CDR works... it is a steady airflow out from the CDR, so ANY blowby into the crankcase just naturally pushes right out there past the diaphragm. When there is no blowby, the turbo sure as heck isn't going to suck up any oil.

Go under the hood, hook up your gauge, start the truck, and then plug the inlet air off... the turbo will suck that gauge flat... but as long as your air filter is allowing good flow, you won't get vacuum. Path of least resistance.

BTW - it's OK that you don't believe in CDR... it believes in you. :D
 
SmithvilleD said:
Good job on the home-built TM.

I've got the factory coolant sensor/gauge in its stock location & an aftermarket, mechanical sender/gauge in the opposite head's port - don't trust the factory setup precision enough to try compare the two. On the racecar, any temp difference btwn the front & back cylinders showed most when the cooling system was near its limits - when the rad exit temps were higher.
Be interesting to see if you see any differences at your highest summer temps with the loaded stock trailer?
Click to expand...
Will find out i guess,i just thought i would see some diff running high EGT's
Did the filter minder trip as it's supposed to when the filter got more loaded & restrictive
Click to expand...
?nope,never had that yet,thing does work though.(i aint gonna use the word suck here,people get funny ideas)

I measured vacuum btwn the air filter & turbo compressor inlet in the first couple weeks of driving my fresh engine to get some idea if my air cleaner setup flowed adequately. With stock chip boost levels (peak 8-9 psi), peak vacuum levels looked to be btwn 1-2 psi. Appeared to be a relatively small pressure difference before & after the filter. I'll measure this again as I go stepwise to higher boost/fuel on the stock GM-4 turbo, & again w/ the Holset. Should show if/when the current air cleaner becomes restrictive.
Click to expand...
So, how did you get to get some meassurable vac.I took it in same location as you. Maybe my filter flows better?

I'd really like also have a large, unrestrictive hot-wire mass airflow sensor in the air intake & be able to datalog actual airflow relative to rpm/boost & other parameters. One of my past gas turbo engine projects used an aftermarket hot-wire MAS along with datalogging. Going thru a run stepwise watching the parameters change in small time intervals was helpful in understanding what's going on.

Accurate MAS readings could be helpful in better understanding the flow differences in the various turbo's being run on the 6.5. This is interesting to me because diesels run such a wide variety of air/fuel ratios compared to gassers. Seeing what/if any power differences went with changes in boost/airflow at a given rpm & fuel rate. You could make better, more analytical judgements on what the ideal boost/airflow rate is for different conditions. How/when additional airflow adds power & how it impacts EGT etc.

If EFI Live has these datalogging & graphic display/playback functions, that makes me a bit envious of the DMax guys using it.
Click to expand...
the rest of your post makes my head spin.(i keep thinking what tricks to teach eddzed's wife)):h
 
bison said:
the rest of your post makes my head spin.(i keep thinking what tricks to teach eddzed's wife)):h
Click to expand...

Women with skills is certainly a more interesting subject:D

Reminds me of a classic Andrew Dice Clay line from years back. He sees a couple in the front row & asks the guy if they're together, and the guy answers "yes".

Next he baits the guy with the question "Is she good?" to which the guy answers as you'd expect him to, "yes".

Next line - "How do you 'spose she got that way!"
 
Matt Bachand said:
Perhaps there would only be vacuum if the air intake was inadequate or clogged. Otherwise just flow.

Sucking out of a coffee stirrer - vacuum, inadequate CFM allowed by

Sucking out of a large shop-vac hose (patooie) - no vacuum, adequate CFM allowed

Perhaps?
Click to expand...
Perhaps you should get in tatch with edzzed's honey,judged by above.
 
JiFaire said:
It's a function of airflow, Bison, but it's an open system... the 'pull' of air (and it's there, no doubts) goes into the turbo. But... it goes in from the easiest possible area, just like water finding its' own level.

If the turbo can pull air easily from the filter, then it won't pull against the (closed) gauge. That's why the CDR works... it is a steady airflow out from the CDR, so ANY blowby into the crankcase just naturally pushes right out there past the diaphragm. When there is no blowby, the turbo sure as heck isn't going to suck up any oil.
Click to expand...
Exactly,that is why i have said many a time,venting the tuna can to the atmosfeer wont harm the engine and cuts back on oil use on engines with high blowby.IMO, the diagram only closes when the airfilter gets dirty creating more vac post filter.



Go under the hood, hook up your gauge, start the truck, and then plug the inlet air off... the turbo will suck that gauge flat... but as long as your air filter is allowing good flow, you won't get vacuum. Path of least resistance.

BTW - it's OK that you don't believe in CDR... it believes in you. :D
Click to expand...
Click to expand...
:rolleyes5::smile5:
 
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