Turbo Surge, Turbonetics T61, GTP38R, & GT38 w/ 99.5 & Early 99 Wheels.
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10-19-2007, 10:03 PM
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Turbo Surge, Turbonetics T61, GTP38R, & GT38 w/ 99.5 & Early 99 Wheels.
Thanks to Tenn's data I've put together a preliminary model for a 99.5 engine. It's still a work in progress, but I just used it to analyze 99.5 engine air flow vs the surge performance of 4 popular turbos, the Turbonetics Ball Buster T61, the Garrett GTP38R, and the stock 99.5 GT38 with the stock Late (L99.5) compressor wheel, and with an Early (E99) wheel, which is also called the WW or the Banks wheel, but they're all the same wheel.
The bottom line is that for controlling surge at the same nominal engine operating conditions, the Turbonetics is by far the best, the Garrett GTP38R is the same as the stock GT38 with an E99 wheel, and the stock GT38 with the stock L99.5 wheel flat out sucks, or to be more precise, it stops sucking at a BP that's about 5 psi lower than for the E99 wheel. If you follow the discussion of pic #2, you'll see why the use of an E99 wheel shouldn't be discouraged just because it reduces your surge free max BP by a couple of psi at 3200 RPM. I show why the E99 wheel gives a higher max HP, and much better performance for towing!
Pic #3 shows why towing at higher altitudes is the "elephant graveyard" for turbos! Mine failed in the mountains, and I've seen at least 6 posts where others had turbo failures in the mountains, and several weren't even towing! After I got a rebuilt early 99 turbo that came with a late 99.5 wheel, I learned the hard way towing the Grapevine the results I now see in my graphs, which clearly show how much worse surge is with a L99.5 wheel vs an E99 wheel, and how much worse surge is in general at higher altitudes!
Pic #1 is the input data to my model for the reference graph in pic #2. The key inputs of pressure and temp at the air filter inlet were chosen to give a turbo inlet pressure of 13.95 psi and an inlet temp of 85 F to match the standard reference conditions that are used when turbos are run on a test bench to measure their compressor maps. In this bench test the compressor wheel is spun at a fixed RPM, and data is first taken with the turbo outlet wide open. This determines the maximum air flow and a single data point on the choke line for the given wheel RPM. Then the turbo outlet is gradually closed off to reduce the air flow while the wheel RPM is kept constant. Eventually the compressor stalls, and this determines the data point on the surge line for the given wheel RPM. This test is repeated for a number of fixed wheel RPM's, and the outlet-to-inlet pressure ratio, PR, is plotted vs inlet MAF for each constant wheel RPM speed line, and that's how a compressor map is generated.
The lines of constant efficiency are determined from measurements of outlet-to-inlet temp differences, and they form elongated ovals on the map that are approximately parallel to the surge line and their centers are offset about 10 to 15 MAF lb/min to the right. The complication for using these maps is that they only apply for the standard test bench reference conditions with a turbo inlet of 13.95 psi and 85 F.
As I studied up in this area I noticed that everyone takes their actual engine air flow data and corrects it to the standard reference condition for a turbo bench test so they can plot their corrected data directly on a bench test compressor map. In the pic #2 graph I operated the engine at the standard reference condition for a bench test, so the MAF & IVAF and other parameters on the graph are actual engine data, and likewise the surge lines are the same as for a bench test compressor map.
Instead of following what others do, I correct the compressor map data to the actual engine operating conditions, as this gives a much nicer way of understanding what's happing as engine conditions change. Pic #3 is for an altitude of 6 K ft, which reduces the turbo inlet pressure to 11.19 psi, but I kept the turbo inlet temp at the standard 85 F reference value, so that pressure is the only parameter that was changed from pic #2. In pic #3 all the engine data and other operating parameters on the graph are still actual values, but the compressor map surge lines are corrected for the higher altitude to give the map you'd get if you ran the turbo bench test at the actual 6 K altitude. In other words, everyone else converts their engine data to what it would be if the engine were run on the test bench, but I convert the turbo bench test data to how the turbo actually performs on the engine at, in this case, a 6 K ft altitude.
There's some interesting physics relating to this compressor map correction, and I'm pretty sure none of the "compressor map" sites understand it because they just present the correction formulas, mumble something about air density, and wave their hands as if it should be obvious to all why corrections are needed and how and what they're really correcting for! But that's a story for another day. For now I'm also just giving the correction formulas in pic # 4. Pic # 5 is a map for the GTP38R, and I overlaid the surge line from the Turbonetics T61 map, and the line for the GT38 with the L99.5 wheel on that map. As indicated, the GT38 with an E99 wheel matches the surge line for the GTP38R very closely. I included pic #6 because it's a neat overview, and to once again emphasize that the darker blue color for the #1 turbo inlet arrow means that your turbo wants the coolest possible air going into its inlet.
Looking at pic #2, as I tow a grade at 2000 RPM, which is 65 MPH with my 4.10 diff, I need to progressively apply an increasing amount of throttle to keep my speed constant. This moves me along the blue 2000 RPM curve (it's not quite a straight line) from left to right which increases BP, IVAF, MAF, and HP. All along the blue 2000 RPM curve the volume air flow into the cylinders (CVAF) is a constant 257 CFM. The reason the inlet volume air flow (IVAF) and MAF increase at a constant engine RPM as you push harder on the throttle is because the higher BP increases the cylinder air density (CAD), and this puts more lbs of air into the cylinders for each intake stroke even though the cylinder volume air flow is constant.
If you follow the blue curve up to where it hits the red surge line, you start encountering surge at about BP=17 psi with the stock L99.5 wheel. Note that the BP scale on the right is separate from the PR scale on the left, and the PR scale is used to generate the grid reference lines, so the BP values don't exactly match these reference lines. You can follow the blue curve up to a BP of about 22.5 psi before hitting the lime green surge line for an E99 wheel. That's more than a 5 psi improvement in surge free boost with an E99 vs the stock L99.5 wheel, and that provides about 5 lb/min more MAF! I've also confirmed this conclusion with my SOP surge detector before I had the L99.5 wheel on my rebuilt turbo changed to an E99 wheel.
You can see from the pic #2 graph what the "poor mans" solution for surge is. You just downshift to 3rd, and now at 65 MPH you're turning about 2800 RPM, and now you're operating on the pink 2800 RPM curve at about a BP=16 psi to have the same HP as for 2000 RPM at 17 psi. The volumetric and thermodynamic efficiencies are maximum at 2000 RPM, and lower at 2800 RPM, however, at 2800 RPM you can increase BP by an additional 7 psi, to 23 psi before hitting the red surge line. So in 3rd gear you've got some surge margin to play with.
Now if you look at the gray 3200 RPM line, it shows a surge free max BP=28 psi with a L99.5 wheel. Maybe the E99 wheel only generates say 26 psi at this RPM, but consider this. At 2800 RPM where you get max HP, surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99.5 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP than the L99.5 wheel! As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!
Note that in the pic #3 graph the BP scale vs the PR scale is different than the one in pic #2, because at altitude the turbo produces less BP for a given PR. Now you hit the red surge line at BP=13.5 psi in 4th at 2000 RPM, but downshifting to 3rd still allows a BP=19 psi. I'll be giving a more detailed post on how altitude effects turbo and engine performance.
I considered plotting compressor wheel RPM and turbo efficiency lines, but the graph is already so cluttered it's getting hard to read. However, one can just eyeball the compressor maps and use the surge lines as a reference to see about where the other map features are located on my graphs. For example the maximum efficiency is about 10 to 15 lb/min of MAF in a horizontal direction to the right of the surge line. That says the highest efficiency occurs for a BP of 10 to 12 psi and RPM between 2000 to 2400.
You can also use these graphs to see why you encounter surge if you apply too much throttle when accelerating from a stop. The lowest RPM curve is the green 1600 line, but if you imagine the other lower RPM lines to the left of that, you'll see that it doesn't take much BP to drive the turbo into surge at lower RPM. This is why disconnecting the red line eats your turbo for lunch, and why the stock waste gate control shouldn't be messed with, unless you're in the market for a new turbo anyway.
Even though this surge when starting up too aggressively is a momentary condition, the wear and tear on the turbo bearing accumulates. It's not like being pregnant, you can have a little surge and not even realize it. It takes significant surge to make the noises that people report, and for sure this is the most damaging surge condition, but surge comes on gradually in the vicinity of these surge lines, and if you keep pushing it, then surge announces itself with the tell tale noises that indicate a higher level of more immediate damage.
The bottom line is that for controlling surge at the same nominal engine operating conditions, the Turbonetics is by far the best, the Garrett GTP38R is the same as the stock GT38 with an E99 wheel, and the stock GT38 with the stock L99.5 wheel flat out sucks, or to be more precise, it stops sucking at a BP that's about 5 psi lower than for the E99 wheel. If you follow the discussion of pic #2, you'll see why the use of an E99 wheel shouldn't be discouraged just because it reduces your surge free max BP by a couple of psi at 3200 RPM. I show why the E99 wheel gives a higher max HP, and much better performance for towing!
Pic #3 shows why towing at higher altitudes is the "elephant graveyard" for turbos! Mine failed in the mountains, and I've seen at least 6 posts where others had turbo failures in the mountains, and several weren't even towing! After I got a rebuilt early 99 turbo that came with a late 99.5 wheel, I learned the hard way towing the Grapevine the results I now see in my graphs, which clearly show how much worse surge is with a L99.5 wheel vs an E99 wheel, and how much worse surge is in general at higher altitudes!
Pic #1 is the input data to my model for the reference graph in pic #2. The key inputs of pressure and temp at the air filter inlet were chosen to give a turbo inlet pressure of 13.95 psi and an inlet temp of 85 F to match the standard reference conditions that are used when turbos are run on a test bench to measure their compressor maps. In this bench test the compressor wheel is spun at a fixed RPM, and data is first taken with the turbo outlet wide open. This determines the maximum air flow and a single data point on the choke line for the given wheel RPM. Then the turbo outlet is gradually closed off to reduce the air flow while the wheel RPM is kept constant. Eventually the compressor stalls, and this determines the data point on the surge line for the given wheel RPM. This test is repeated for a number of fixed wheel RPM's, and the outlet-to-inlet pressure ratio, PR, is plotted vs inlet MAF for each constant wheel RPM speed line, and that's how a compressor map is generated.
The lines of constant efficiency are determined from measurements of outlet-to-inlet temp differences, and they form elongated ovals on the map that are approximately parallel to the surge line and their centers are offset about 10 to 15 MAF lb/min to the right. The complication for using these maps is that they only apply for the standard test bench reference conditions with a turbo inlet of 13.95 psi and 85 F.
As I studied up in this area I noticed that everyone takes their actual engine air flow data and corrects it to the standard reference condition for a turbo bench test so they can plot their corrected data directly on a bench test compressor map. In the pic #2 graph I operated the engine at the standard reference condition for a bench test, so the MAF & IVAF and other parameters on the graph are actual engine data, and likewise the surge lines are the same as for a bench test compressor map.
Instead of following what others do, I correct the compressor map data to the actual engine operating conditions, as this gives a much nicer way of understanding what's happing as engine conditions change. Pic #3 is for an altitude of 6 K ft, which reduces the turbo inlet pressure to 11.19 psi, but I kept the turbo inlet temp at the standard 85 F reference value, so that pressure is the only parameter that was changed from pic #2. In pic #3 all the engine data and other operating parameters on the graph are still actual values, but the compressor map surge lines are corrected for the higher altitude to give the map you'd get if you ran the turbo bench test at the actual 6 K altitude. In other words, everyone else converts their engine data to what it would be if the engine were run on the test bench, but I convert the turbo bench test data to how the turbo actually performs on the engine at, in this case, a 6 K ft altitude.
There's some interesting physics relating to this compressor map correction, and I'm pretty sure none of the "compressor map" sites understand it because they just present the correction formulas, mumble something about air density, and wave their hands as if it should be obvious to all why corrections are needed and how and what they're really correcting for! But that's a story for another day. For now I'm also just giving the correction formulas in pic # 4. Pic # 5 is a map for the GTP38R, and I overlaid the surge line from the Turbonetics T61 map, and the line for the GT38 with the L99.5 wheel on that map. As indicated, the GT38 with an E99 wheel matches the surge line for the GTP38R very closely. I included pic #6 because it's a neat overview, and to once again emphasize that the darker blue color for the #1 turbo inlet arrow means that your turbo wants the coolest possible air going into its inlet.
Looking at pic #2, as I tow a grade at 2000 RPM, which is 65 MPH with my 4.10 diff, I need to progressively apply an increasing amount of throttle to keep my speed constant. This moves me along the blue 2000 RPM curve (it's not quite a straight line) from left to right which increases BP, IVAF, MAF, and HP. All along the blue 2000 RPM curve the volume air flow into the cylinders (CVAF) is a constant 257 CFM. The reason the inlet volume air flow (IVAF) and MAF increase at a constant engine RPM as you push harder on the throttle is because the higher BP increases the cylinder air density (CAD), and this puts more lbs of air into the cylinders for each intake stroke even though the cylinder volume air flow is constant.
If you follow the blue curve up to where it hits the red surge line, you start encountering surge at about BP=17 psi with the stock L99.5 wheel. Note that the BP scale on the right is separate from the PR scale on the left, and the PR scale is used to generate the grid reference lines, so the BP values don't exactly match these reference lines. You can follow the blue curve up to a BP of about 22.5 psi before hitting the lime green surge line for an E99 wheel. That's more than a 5 psi improvement in surge free boost with an E99 vs the stock L99.5 wheel, and that provides about 5 lb/min more MAF! I've also confirmed this conclusion with my SOP surge detector before I had the L99.5 wheel on my rebuilt turbo changed to an E99 wheel.
You can see from the pic #2 graph what the "poor mans" solution for surge is. You just downshift to 3rd, and now at 65 MPH you're turning about 2800 RPM, and now you're operating on the pink 2800 RPM curve at about a BP=16 psi to have the same HP as for 2000 RPM at 17 psi. The volumetric and thermodynamic efficiencies are maximum at 2000 RPM, and lower at 2800 RPM, however, at 2800 RPM you can increase BP by an additional 7 psi, to 23 psi before hitting the red surge line. So in 3rd gear you've got some surge margin to play with.
Now if you look at the gray 3200 RPM line, it shows a surge free max BP=28 psi with a L99.5 wheel. Maybe the E99 wheel only generates say 26 psi at this RPM, but consider this. At 2800 RPM where you get max HP, surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99.5 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP than the L99.5 wheel! As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!
Note that in the pic #3 graph the BP scale vs the PR scale is different than the one in pic #2, because at altitude the turbo produces less BP for a given PR. Now you hit the red surge line at BP=13.5 psi in 4th at 2000 RPM, but downshifting to 3rd still allows a BP=19 psi. I'll be giving a more detailed post on how altitude effects turbo and engine performance.
I considered plotting compressor wheel RPM and turbo efficiency lines, but the graph is already so cluttered it's getting hard to read. However, one can just eyeball the compressor maps and use the surge lines as a reference to see about where the other map features are located on my graphs. For example the maximum efficiency is about 10 to 15 lb/min of MAF in a horizontal direction to the right of the surge line. That says the highest efficiency occurs for a BP of 10 to 12 psi and RPM between 2000 to 2400.
You can also use these graphs to see why you encounter surge if you apply too much throttle when accelerating from a stop. The lowest RPM curve is the green 1600 line, but if you imagine the other lower RPM lines to the left of that, you'll see that it doesn't take much BP to drive the turbo into surge at lower RPM. This is why disconnecting the red line eats your turbo for lunch, and why the stock waste gate control shouldn't be messed with, unless you're in the market for a new turbo anyway.
Even though this surge when starting up too aggressively is a momentary condition, the wear and tear on the turbo bearing accumulates. It's not like being pregnant, you can have a little surge and not even realize it. It takes significant surge to make the noises that people report, and for sure this is the most damaging surge condition, but surge comes on gradually in the vicinity of these surge lines, and if you keep pushing it, then surge announces itself with the tell tale noises that indicate a higher level of more immediate damage.
#2
10-19-2007, 10:04 PM
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Pics For... Surge Analysis
I'm tired of waiting for FTE to fix their site so I can post my pics like before. Here's another version of my pics, but when you click on pics #2, #3, and #5, you need to hit the mouse pointer over the pic and click the "+" enlarge button to see them clearly.
http://h1.ripway.com/ernesteugene/Pic1.bmp
http://h1.ripway.com/ernesteugene/Pic2.bmp
http://h1.ripway.com/ernesteugene/Pic3.bmp
http://h1.ripway.com/ernesteugene/Pic4.bmp
http://h1.ripway.com/ernesteugene/Pic5.bmp
http://h1.ripway.com/ernesteugene/Pic6.jpg
http://h1.ripway.com/ernesteugene/Pic1.bmp
http://h1.ripway.com/ernesteugene/Pic2.bmp
http://h1.ripway.com/ernesteugene/Pic3.bmp
http://h1.ripway.com/ernesteugene/Pic4.bmp
http://h1.ripway.com/ernesteugene/Pic5.bmp
http://h1.ripway.com/ernesteugene/Pic6.jpg
#3
10-19-2007, 10:11 PM
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10-19-2007, 10:49 PM
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Faster loading pics!
These versions of the same pics are smaller size and load faster!
http://h1.ripway.com/ernesteugene/1DataTable.jpg
http://h1.ripway.com/ernesteugene/2Map_Ref.jpg
http://h1.ripway.com/ernesteugene/3Map_6K.jpg
http://h1.ripway.com/ernesteugene/4Terms.jpg
http://h1.ripway.com/ernesteugene/5Map.jpg
http://h1.ripway.com/ernesteugene/6Turbo.jpg
http://h1.ripway.com/ernesteugene/1DataTable.jpg
http://h1.ripway.com/ernesteugene/2Map_Ref.jpg
http://h1.ripway.com/ernesteugene/3Map_6K.jpg
http://h1.ripway.com/ernesteugene/4Terms.jpg
http://h1.ripway.com/ernesteugene/5Map.jpg
http://h1.ripway.com/ernesteugene/6Turbo.jpg
#5
10-19-2007, 11:31 PM
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Originally Posted by ernesteugene
If you follow the blue curve up to where it hits the red surge line, you start encountering surge at about BP=17 psi with the stock L99.5 wheel. Note that the BP scale on the right is separate from the PR scale on the left, and the PR scale is used to generate the grid reference lines, so the BP values don't exactly match these reference lines. You can follow the blue curve up to a BP of about 22.5 psi before hitting the lime green surge line for an E99 wheel. That's more than a 5 psi improvement in surge free boost with an E99 vs the stock L99.5 wheel, and that provides about 5 lb/min more MAF! I've also confirmed this conclusion with my SOP surge detector before I had the L99.5 wheel on my rebuilt turbo changed to an E99 wheel.
You can see from the pic #2 graph what the "poor mans" solution for surge is. You just downshift to 3rd, and now at 65 MPH you're turning about 2800 RPM, and now you're operating on the pink 2800 RPM curve at about a BP=16 psi to have the same HP as for 2000 RPM at 17 psi. The volumetric and thermodynamic efficiencies are maximum at 2000 RPM, and lower at 2800 RPM, however, at 2800 RPM you can increase BP by an additional 7 psi, to 23 psi before hitting the red surge line. So in 3rd gear you've got some surge margin to play with.
Now if you look at the gray 3200 RPM line, it shows a surge free max BP=28 psi with a L99.5 wheel. Maybe the E99 wheel only generates say 26 psi at this RPM, but consider this. At 2800 RPM where you get max HP, surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99.5 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP than the L99.5 wheel! As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!
You can see from the pic #2 graph what the "poor mans" solution for surge is. You just downshift to 3rd, and now at 65 MPH you're turning about 2800 RPM, and now you're operating on the pink 2800 RPM curve at about a BP=16 psi to have the same HP as for 2000 RPM at 17 psi. The volumetric and thermodynamic efficiencies are maximum at 2000 RPM, and lower at 2800 RPM, however, at 2800 RPM you can increase BP by an additional 7 psi, to 23 psi before hitting the red surge line. So in 3rd gear you've got some surge margin to play with.
Now if you look at the gray 3200 RPM line, it shows a surge free max BP=28 psi with a L99.5 wheel. Maybe the E99 wheel only generates say 26 psi at this RPM, but consider this. At 2800 RPM where you get max HP, surge limits you to a max BP=23 psi (MAF=42) with a L99.5 wheel, but with the E99.5 wheel you can use your max BP of 26 psi, have a 4 psi surge margin, and get MAF=44 lb/min which provides more HP than the L99.5 wheel! As you look at RPM's lower than 2800 the E99 wheel has an even larger advantage over the L99.5 version. So let's stop discouraging the use of the E99 wheel based on a meaningless reduction of about 2 psi BP at 3200 RPM!
#6
10-20-2007, 12:17 AM
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Once again Gene, your data analysis is amazing, and I have an engineering background. First Rate stuff, really........
I, too, can backup the turbo failure data at high altitude. I live at 9000ft, and I have been through 2 stock GT38's on my '03 7.3. I have just now crossed the 90K mark. The first GT38 went at 42k miles, the EBPV stuck closed and caused a moderate oil leak from the seals. Warranty. Then, at 81k miles, I started to get a weird howl from the turbo at spool-up and when it spun down as well. Eventually, I was losing max boost pressure, and could only make a max boost of 16psi even with Jody's 100hp program. Upon removal of the turbo, I found tons of issues. The journal where the shaft bearing sat in the back plate of the compressor housing was missing 1/4 of that cutout. It was in the oil pan. Also, for what reason I do not know, the exhaust turbine blades were very chopped up on the outside trailing edges, the blades were missing alot of surface area. I still have that dismantaled turbo if anyone wants pics or part discriptions from it. The TN unit on the truck have been nothing short of perfect, makes 25psi on average with shift spikes near 30psi, going across a Spearco 6.0 IC with minimal boost losses. The Ford dealer even admitted that our high altitude is murder on diesel turbos across the board.
Hoping my upgrades will keep my 7.3 running for a long time. Even with the challenge of thin air......
-Kevin
I, too, can backup the turbo failure data at high altitude. I live at 9000ft, and I have been through 2 stock GT38's on my '03 7.3. I have just now crossed the 90K mark. The first GT38 went at 42k miles, the EBPV stuck closed and caused a moderate oil leak from the seals. Warranty. Then, at 81k miles, I started to get a weird howl from the turbo at spool-up and when it spun down as well. Eventually, I was losing max boost pressure, and could only make a max boost of 16psi even with Jody's 100hp program. Upon removal of the turbo, I found tons of issues. The journal where the shaft bearing sat in the back plate of the compressor housing was missing 1/4 of that cutout. It was in the oil pan. Also, for what reason I do not know, the exhaust turbine blades were very chopped up on the outside trailing edges, the blades were missing alot of surface area. I still have that dismantaled turbo if anyone wants pics or part discriptions from it. The TN unit on the truck have been nothing short of perfect, makes 25psi on average with shift spikes near 30psi, going across a Spearco 6.0 IC with minimal boost losses. The Ford dealer even admitted that our high altitude is murder on diesel turbos across the board.
Hoping my upgrades will keep my 7.3 running for a long time. Even with the challenge of thin air......
-Kevin
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10-20-2007, 12:41 AM
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10-20-2007, 12:45 AM
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#9
10-20-2007, 03:29 AM
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Originally Posted by k2vailkid
... Once again Gene, your data analysis is amazing, and I have an engineering background. First Rate stuff, really ...
Originally Posted by k2vailkid
... I live at 9000ft, and I have been through 2 stock GT38's on my '03 7.3. The Ford dealer even admitted that our high altitude is murder on diesel turbos across the board ...
(3x 6.8L Triton V10's) + (236K mi) = (2x 7.3L PSD's) + (2x Turbo's) + (1x 4R100) + (259K mi)
which shows how hard altitude is on both types of engines, and that got me interested in doing an analysis to compare high altitude performance of normally aspirated and turbocharged engines. Here's the link to the Yellowstone post... https://www.ford-trucks.com/forums/647541-performance-equation-for-the-6-8l-triton-v10-versus-the-7-3l-psd.html#post5079171 and here's one to the first installment of the altitude analysis... https://www.ford-trucks.com/forums/653632-high-altitude-effects-part-1-cooling-system-1-of-2-a.html#post5157106 My next installment should be done soon.
Originally Posted by k2vailkid
... The TN unit on the truck have been nothing short of perfect, makes 25psi on average with shift spikes near 30psi, going across a Spearco 6.0 IC with minimal boost losses ... -Kevin
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10-20-2007, 04:14 AM
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Originally Posted by Tenn01PSD350
Hmmm. It would seem that this data would make Joe very happy as he is a devout WW supporter. I need more time to digest that, and perhaps a WW test is in my future for testing too. What program are you using to plot data Gene? BTW, I think Joe was really trying to help with your previous post but you didn't wait for him to correct that.
I'm not sure Joe will like my conclusion regarding the red line, because he runs with his disconnected, and I don't think he babies it when pulling away from traffic lights. At least he's got the E99 wheel, but if you look at pic #2 you see that all the surge lines start to merge together at low air flow, which is the case when accelerating from a dead stop.
I use Excel to do the graphs, and the first set of links that take awhile to download are for the bitmap versions that are much easier to read than the email jpg versions that I normally post using FTE. It would be nice if you could click a link and get a pic up in one window, and read the text in another, but I haven't figured out how to do that.
#12
10-20-2007, 08:11 AM
Originally Posted by ernesteugene
Yes I know Joe was trying to helpful, he even took the time once to measure the blade angles on his compressor wheel to help me with an analysis. Joe, I'm sorry I yelled at you, but I'd been fighting with the FTE site, my computer, and trying to figure out how to use my new ripway account to post the pics, and then Tenn said he wouldn't read my post, etc... I've seen other threads that don't fit in my window and they're very hard to read, and no matter how wide I stretch out my FTE window they still won't fit?
I'm not sure Joe will like my conclusion regarding the red line, because he runs with his disconnected, and I don't think he babies it when pulling away from traffic lights. At least he's got the E99 wheel, but if you look at pic #2 you see that all the surge lines start to merge together at low air flow, which is the case when accelerating from a dead stop.
I use Excel to do the graphs, and the first set of links that take awhile to download are for the bitmap versions that are much easier to read than the email jpg versions that I normally post using FTE. It would be nice if you could click a link and get a pic up in one window, and read the text in another, but I haven't figured out how to do that.
I'm not sure Joe will like my conclusion regarding the red line, because he runs with his disconnected, and I don't think he babies it when pulling away from traffic lights. At least he's got the E99 wheel, but if you look at pic #2 you see that all the surge lines start to merge together at low air flow, which is the case when accelerating from a dead stop.
I use Excel to do the graphs, and the first set of links that take awhile to download are for the bitmap versions that are much easier to read than the email jpg versions that I normally post using FTE. It would be nice if you could click a link and get a pic up in one window, and read the text in another, but I haven't figured out how to do that.
I'm heading out to the garage to **FINALLY** get my in-tank mods done (and a few other things), so I'll be away for a while. But I do appreciate what you do, Gene. I know sometimes we have different oppinions on what all this means, but without any analysis, it's just guesses.
And yes I do like the way the early wheel fixed the surge/overboost problems on my truck. For me, it was a perfect combination of wins. I do run without the WG line, but I don't treat it as bad as you may think. I usually end up running across folks wanting to run when I'm already on the interstate/tollway here going to work. That said, I do run into the occasion @$$clown at a light. Just yesterday one in a "5.9 R/T" Dakota tried to take me. I think I surprised him when he took off (I wasn't thinking about racing him right then so he got me off the line), then I started catching & passing him. He then let off the throttle because he knew I had him. I was along side him and almost passed him when he shut it down. I actaully surprised myself with that one. I figure those little things were pretty fast. Well, I guess they are, but I'm a little faster.
Last edited by Izzy351; 10-20-2007 at 08:14 AM.
#14
10-20-2007, 09:12 AM
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Originally Posted by ernesteugene
Thanks for the complement, the one thing I miss most in retirement is not running across many engineers to compare notes with. You must be in decent shape to live at that altitude!
For work now I ski & also am a wine sommelier, so I am very much out of engineering type practice, but every now and then some project comes out better from sitting down and thinking things through. I'm sure you understand.....
Originally Posted by ernesteugene
Which TN model do you have, is it the T61 I used in my comparison?
That IC is a really tight fit. I'd like to figure out how to get the radiator away from it a bit, as they rest on each other. Might help intake temps some more.....
Last edited by k2vailkid; 10-20-2007 at 09:16 AM.
#15
10-20-2007, 09:48 AM
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