+- Rawze.com: Rawze's ISX Technical Discussion and more (http://rawze.com/forums)
+-- Forum: Big Truck Technical Discussion... (/forumdisplay.php?fid=1)
+--- Forum: ISX Related Help (/forumdisplay.php?fid=68)
+--- Thread: turbo blanket (/showthread.php?tid=6868)
Pages: 1 2
RE: turbo blanket - Rawze - 12-21-2020
(12-21-2020 )Smiling lemon Wrote: Since i have the time now I'll elaborate. So easy turbo blankets and headed wraps increase performance is two part.
1st: keep heat within the pipe before turbo i.e. more heat more pressure. More pressure on the turbine allows higher compressor speed increasing available boost.
2nd: insulating the turbine from the compressor reducing intake charge temperatures. Lower temperatures higher air density, Bigger bang, more power. And you can increase this effect further by using ice on a liquid intercooler or N2o on a air intercooler
Pros more power
Con higher temperatures in your turbo.
Long upgrades it becomes irrelevant do to the heat soak. Because of the higher temperatures you also cook the bearings and any oil in the turbo is going to be fried. Variable geometry turbo components also do not hold up to high temperature
I think you have some things a little sideways there. I have seen turbo blankets on several trucks that have come around here, taken measurements and compared a truck or 2 with them on and off.
-- Thermal camera clearly shows MORE heat soak from heat being trapped at the turbo and therefore higher temps into the CAC. - I don't know where you got some of those statements from but it was not from anyone that actually measured anything.
More heat soak = a shorter turbocharger lifespan and if your CAC is not adequate to handle the extra added heat because someone installed a turbo sock onto the turbo like in a prostar with its smaller sized CAC unit, then this means efficiency losses for the engine.
I.E.> A turbo sock on a turbo inside a prostar or cascadia and its small CAC will lead to higher than normal intake temps and efficiency loss. One installed on a W900 and its large CAC will not likely have this same cold-side CAC thermal issues but the turbo will still be running significantly hotter than it should, shortening its life. Big square-nose truck have other problems though, ... but that is a whole other subject.
-- With regard to turbo sock and performance on the ISX ... It will not make any measurable difference on an ISX. It has been tested... and shows nothing. The turbocharger is not the issue, and putting a sock on one only makes its overall core temps higher than normal and this is not so good for them, especially when pulling freight.
- As far as wrapping things and improving exhaust thru-put for performance or efficiency gains .. wrapping the exhaust manifold helps considerably more than wrapping the turbo. Wrapping the entire exhaust system form the back of the turbo all the way to the output of the stack (minus the turbo itself) has the biggest and most effective gains for both efficiency and performance.
- Cutting and directing the outlet/end tip of the exhaust piping so that it is angled and creates a venturi effect in the wind helps too. I have seen that make a measurable difference as well. Putting the whole exhaust stack into the air stream is bad, but an exhaust designed for just the tip to be so it can take advantage of venturi effect, this works.
- Aftermarket hi-flo exhaust manifolds for the ISX have shown ZERO measurable gains whatsoever below 800+ horsepower. They also did not show any differences/improvements whatsoever on a thermal imaging camera. Don't believe any of the marketing garbage you see out there for exhaust manifolds. It will only empty your wallet.
- There are aftermarket intake manifolds (and CM570 factory manifolds) that fit the CM870 specifically out there that claim to be hi-flow. Those will have slight improvement above 500~ish HP due to the venturi circuit being cut out of the center of them or missing. They make zero difference below 500~+ hp though and require an egr-delete. The factory manifold has no flow restrictions below this point. For those with CM870's, they are deleted, and they are set above 500~ish horsepower, this is not a bad investment.
In Contrast to this though, NEWER engines like the CM871, and newer common rail engines, no aftermarket manifold has ever made a difference. This problem was essentially solved in the factory manifold. Non-factory manifolds however have some risk. This is because many of them are not designed to even out the distribution of intake air evenly to the cylinders like the factory unit does. This makes cylinders 5 and 6 run hotter than the rest, and imbalances the engine slightly. Therefore I am not a proponent of them in general on anything newer than a CM870... Just a warning.
As far as the VGT and heat.... Holset says 1350-F for 3 minutes at a time or 1250-F continuous. Experience and helping others tells me though that keeping the exhaust manifold/outer housing temp below 950F ( below 1100F with a pyro mounted post-turbo) is what makes them last 500+k miles at a time. As others have pointed out, this is amplified by installing a turbo blanket. Someone would be far better off if they installed an exhaust manifold wrap and then proceeded to wrap their entire exhaust as much as possible without wrapping the turbo itself.
-- Lastly, the exhaust wrap does not keep in more heat making more pressure.. That is not correct information. It is an issue of heat, flow, and density all combined. As exhaust gasses cool, they become exponentially more dense. Inside a confined space, this presents a problem and creates resistance making the engine work harder to push them thru the exhaust piping.
A simplified description of this would be to imagine a metal straw you are blowing exhaust air thru. Keep the entire straw and air temp the same (by wrapping it up well) and the air moves smoothly. Cool the air by a few hundred degrees by heat absorption of the metal in the straw, cooling it off, and by the time the air reached the other end, it is so dense that it is like trying to blow thru a cotton ball that has been stuffed inside it. The longer the straw is and the more times it bends also increases resistance too.
I.E.> Rapid exhaust gas cooling in the exhaust piping as it moves along its length creates resistance and a "pillow" effect up-stream, all the way to the engine and therefore efficiency losses. - The fewest number of bends in the exhaust, the least amount of heat-loss, and any component that does get hot.. should stay as warm as possible to prevent it from constantly bleeding off exhaust heat, the VG turbo itself being the exception. It is not "AIR" your trying to get to the other end...but "HEAT", and anything that can absorb or reflect that "heat" .. makes for a lower efficiency.
I should also mention that diesel engines have too high of a compression ratio to benefit from "tuned" exhaust like some cars do ... It is simply a matter of "the absolute least exhaust resistance possible" with regards to a turbocharged diesel.
here are some related threads/posts ...
http://rawze.com/forums/showthread.php?tid=1128&pid=9593#pid9593
RE: turbo blanket - DVT873 - 12-22-2020
Another possible benefit of wrapping the exhaust all the way to the DPF is to keep the DPF temp at 600F or better. Mild regen starts around 600F so in theory fewer active (dosing fuel) regens will be needed. Early on some mfrs wrapped their systems pretty completely. Not so much anymore. Maybe they want the money from aftertreatment system repairs.
RE: turbo blanket - JimT - 01-07-2021
(12-21-2020 )Rawze Wrote: Someone would be far better off if they installed an exhaust manifold wrap and then proceeded to wrap their entire exhaust as much as possible without wrapping the turbo itself.
-- Lastly, the exhaust wrap does not keep in more heat making more pressure.. That is not correct information.
Good to know. Had considered doing this at some point, mainly to reduce heat bleeding into the cab from the weed burner setup on my truck. Put it out of my mind when the dpf was emptied, but might look into in the future if it can actually help increase flow. With all the back and forth of the exhaust piping under my cab there's a lot of surface area to transfer heat.
Although, the extra heat under the cab isn't a bad thing in the winter months...
RE: turbo blanket - Rawze - 01-08-2021
(01-07-2021 )JimT Wrote:(12-21-2020 )Rawze Wrote: Someone would be far better off if they installed an exhaust manifold wrap and then proceeded to wrap their entire exhaust as much as possible without wrapping the turbo itself.
-- Lastly, the exhaust wrap does not keep in more heat making more pressure.. That is not correct information.
Good to know. Had considered doing this at some point, mainly to reduce heat bleeding into the cab from the weed burner setup on my truck. Put it out of my mind when the dpf was emptied, but might look into in the future if it can actually help increase flow. With all the back and forth of the exhaust piping under my cab there's a lot of surface area to transfer heat.
Although, the extra heat under the cab isn't a bad thing in the winter months...
When I installed an exhaust wrap on my pipe between the back of the turbo and the DOC inlet (2011 prostar), it made a huge difference inside the sleeper area of the truck in the summer time. The A/C system did not have to work nearly as hard. I also gained a good 0.2 ~ 0.3 ish mpg.
(speculation)...
I would imagine that some of the fuel mileage gains are from the wrap itself, and some from the A/C not having to work as hard + engine fan not operating on as often. Add it all up and over time it could be more savings than a person might think.
I had someone from the forum that visited me about 4 years ago who wrapped their entire exhaust system starting behind the turbo and converted it to a weed-burner, down pipe in the wind for the venturi effect. They gained easily, a good 0.4~ or more mpg. Again, it was a prostar except his had a 2350 engine, as it was a 2014 model.
RE: turbo blanket - Chamberpains - 01-08-2021
Rawze, I believe you said you used welding blankets and metal ties to secure them. Did your exhaust pipes rot any faster or slower? Just curious if the blankets maybe protected the pipes from corrosion, nature and salt? Any extra or less longevity to note from wrapping the pipes?
RE: turbo blanket - Rawze - 01-09-2021
(01-08-2021 )Chamberpains Wrote: Rawze, I believe you said you used welding blankets and metal ties to secure them. Did your exhaust pipes rot any faster or slower? Just curious if the blankets maybe protected the pipes from corrosion, nature and salt? Any extra or less longevity to note from wrapping the pipes?
so far so good. it has been about 5 years so. I do need to replace the wrap though, it is starting to go bad in a few spots that I did not secure as well as it should have been.