Builds 1988 BJ74 “Number 1” (10 Viewers)
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FJBen
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- #1,002
IH8FAWKING THIEVES!!!
At another building at work today and I came out a few hours later. Hopped in and noticed my glovebox open, things strewn about. The back door was open too.
Hopped out back to see what they stole. They tried to get my sub-box out bug couldn't open the other door to get the big thing out, or got caught in the middle of doing it. I asked the lady next to me who had a soft top jeep and she said she got broke into as well. Stole her sub and amp and rifled through her stuff.
Broad daylight, in a parking lot in the middle of town. Jerks. They ended up stealing only my Leatherman tool that I've had for over 10 years so thats a bit annoying. I suppose time to take the stereo out and go full stealth with a bluetooth and hidden sub setup or just bluetooth speaker.
At another building at work today and I came out a few hours later. Hopped in and noticed my glovebox open, things strewn about. The back door was open too.
Hopped out back to see what they stole. They tried to get my sub-box out bug couldn't open the other door to get the big thing out, or got caught in the middle of doing it. I asked the lady next to me who had a soft top jeep and she said she got broke into as well. Stole her sub and amp and rifled through her stuff.
Broad daylight, in a parking lot in the middle of town. Jerks. They ended up stealing only my Leatherman tool that I've had for over 10 years so thats a bit annoying. I suppose time to take the stereo out and go full stealth with a bluetooth and hidden sub setup or just bluetooth speaker.
FJBen
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- #1,003
Slow progress.
Got the right M8 studs in, looks good.
The right sized crush washers 12mm internal, 18mm external. So far Belmetric is a great place to get all this stuff from.
Got another drain to try. I think this one will work with some modding. A shorten and a bend will have it clearing so I can put a hose on. Eventually I will probably go to AN setup, but that can get pricey in this guessing game of trying to make it all fit and mock up.
Got the right M8 studs in, looks good.
The right sized crush washers 12mm internal, 18mm external. So far Belmetric is a great place to get all this stuff from.
Got another drain to try. I think this one will work with some modding. A shorten and a bend will have it clearing so I can put a hose on. Eventually I will probably go to AN setup, but that can get pricey in this guessing game of trying to make it all fit and mock up.
That should work... awfully close to the "hot spot", but if you can get a longer one, and use a pipe bender to navigate away from the exhaust?
That should keep your rubber hose from melting...
FJBen
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- #1,005
Yeah I'm going to see if I can bend or cut/weld to get it further away. I like the first pipe I had I just don't like that it's slightly smaller than the outlet. Maybe it's not enough to worry about.That should work... awfully close to the "hot spot", but if you can get a longer one, and use a pipe bender to navigate away from the exhaust?
That should keep your rubber hose from melting...
FJBen
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- Thread starter
- #1,010
Pulled the heat shield to check clearances.
I’m pretty sure that elbow I have isn’t going to fit. It will be really tight so back to the drawing board on this one. I've got a few calls out for measurements on some other dump pipes. Worst case I will have to get someone to fab one for me.
And of course a Monday Mural picture just for fun.
I’m pretty sure that elbow I have isn’t going to fit. It will be really tight so back to the drawing board on this one. I've got a few calls out for measurements on some other dump pipes. Worst case I will have to get someone to fab one for me.
And of course a Monday Mural picture just for fun.
Yeah, that is a pretty sharp angle... any time you can make things as free flowing as possible for both intake/exhaust it is advisable. But yes, you need to work with the space you have, and you want to leave SOME clearance because of heat. This is a tough one. The existing port already is at a pretty sharp angle, so at the very least you are not changing that if that is the route you have to go...
At the end of the day you are still going to see a performance gain, and if you don't have neighbors too close you could test the difference with the 90 and just an open exhaust port!!
Do they make something like this for the flange? I originally had the flat exhaust flange on the back of my turbo but changed to one like this. No sure if it will help having the wastegate exit more freely?
I haven't finished my V2.0 exhaust to find out if it makes a difference in EGT yet
I haven't finished my V2.0 exhaust to find out if it makes a difference in EGT yet
FJBen
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- #1,013
Yeah, that is a pretty sharp angle... any time you can make things as free flowing as possible for both intake/exhaust it is advisable. But yes, you need to work with the space you have, and you want to leave SOME clearance because of heat. This is a tough one. The existing port already is at a pretty sharp angle, so at the very least you are not changing that if that is the route you have to go...
At the end of the day you are still going to see a performance gain, and if you don't have neighbors too close you could test the difference with the 90 and just an open exhaust port!!
Oh yeah, the first will be pretty much wide open off the downpipe so I will test both. No close neighbors at all so it will be nice and loud lol.
I don’t know if this would work, it’s for a 12HT. From down under.
FJBen
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- Thread starter
- #1,016
Exhaust. I always try to learn about all the systems on a vehicle and why they are designed the way they are and how it effects performance. The easy answer is people say 3" exhaust, but 2.5" is easier to fit. It works great but I kind of want to know the physics behind it.
We know engines are basically air pumps. Air goes in, air goes out. The wrong sizing, shape, restrictions can cause performance problems. Obviously a straight pipe and no bends would be ideal but not realistic.
So what we need to do is figure out how much air this engine needs, and how much exhaust it's going to put out so we can size the pipe correctly. We already know fairly close what the 13BT should need for intake CFM when I sized up the turbo.
13BT, 3400cc = ~208 cubic inches.
208ci x 3400rpm divided by 3,456 = 205cfm (cubic feet/min)
205 x .80*** efficiency = 164cfm (Volumetric efficiency is a moving target. Lots of factors but generalizing will be close enough)
So at 3400RPM, the 13BT uses 164cfm. Thats assuming 0psi, or basically 1 bar/atmosphere. 1 bar is 14.7psi at sea level. The higher you go up, the lower that pressure is. At 5000' in elevation, it's around 12.2psi.
So what air does the engine use without boost and with different levels of boost.
1:0 would be164cfm at 0psi
2:1 that would be 327cfm at 14.7psi
3:1 would be 492cfm at 29.4psi
So more maths:
To figure out how much exhaust I'm flowing out at 14.7psi we use this formula which has some variables that I don't have exact numbers for
EGT + 460 divided by 540 times CFM
So at 1000 EGT we get this
1000 + 460 = 1460.
1460 divided by 540 = 2.70
2.70 times 327cfm = 884cfm in exhaust will be leaving the engine
at 1100 its 944cfm
at 900 it's 823cfm
EGT effects this quite a bit.
Again, this is all at 3400rpm. So in theory the 13BT would put out 800~900cfm in exhaust, maximum. Donaldson did a lot of the math with probably much better numbers for a number of engines. The 4BT is fairly close so this is what they come up with for stock numbers on the 4BT.
View attachment 2824678
The 120HP 4BT, at 2500rpm and 970EGT flows 922cfm. That leads me to believe my numbers arent that far off. the 13BT and 4BT are pretty similar in reality. I'm pushing quite a bit more rpm, which means more CFM. That will be the max cfm on this engine. Ive seen other quick math showing
Now that we are in the ballpark on Exhaust CFM, we can see what size pipes we need.
and a picture in case you don't care to read any of that boring crap above.
We know engines are basically air pumps. Air goes in, air goes out. The wrong sizing, shape, restrictions can cause performance problems. Obviously a straight pipe and no bends would be ideal but not realistic.
So what we need to do is figure out how much air this engine needs, and how much exhaust it's going to put out so we can size the pipe correctly. We already know fairly close what the 13BT should need for intake CFM when I sized up the turbo.
13BT, 3400cc = ~208 cubic inches.
208ci x 3400rpm divided by 3,456 = 205cfm (cubic feet/min)
205 x .80*** efficiency = 164cfm (Volumetric efficiency is a moving target. Lots of factors but generalizing will be close enough)
So at 3400RPM, the 13BT uses 164cfm. Thats assuming 0psi, or basically 1 bar/atmosphere. 1 bar is 14.7psi at sea level. The higher you go up, the lower that pressure is. At 5000' in elevation, it's around 12.2psi.
So what air does the engine use without boost and with different levels of boost.
1:0 would be164cfm at 0psi
2:1 that would be 327cfm at 14.7psi
3:1 would be 492cfm at 29.4psi
So more maths:
To figure out how much exhaust I'm flowing out at 14.7psi we use this formula which has some variables that I don't have exact numbers for
EGT + 460 divided by 540 times CFM
So at 1000 EGT we get this
1000 + 460 = 1460.
1460 divided by 540 = 2.70
2.70 times 327cfm = 884cfm in exhaust will be leaving the engine
at 1100 its 944cfm
at 900 it's 823cfm
EGT effects this quite a bit.
Again, this is all at 3400rpm. So in theory the 13BT would put out 800~900cfm in exhaust, maximum. Donaldson did a lot of the math with probably much better numbers for a number of engines. The 4BT is fairly close so this is what they come up with for stock numbers on the 4BT.
View attachment 2824678
The 120HP 4BT, at 2500rpm and 970EGT flows 922cfm. That leads me to believe my numbers arent that far off. the 13BT and 4BT are pretty similar in reality. I'm pushing quite a bit more rpm, which means more CFM. That will be the max cfm on this engine. Ive seen other quick math showing
Now that we are in the ballpark on Exhaust CFM, we can see what size pipes we need.
and a picture in case you don't care to read any of that boring crap above.
yes
FJBen
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- Thread starter
- #1,020
PIpe sizing and exhaust. There is A LOT of informations, and mis-information on this. I was actually surprised to learn how different everyone treats this.
A section of straight pipe the length of a typical muffler flows about 115 cfm per square inch.. This is according to David Vizard who wrote books and article on extensive testing of exhaust, flow, pipe size, HP etc. I'm going to not go very deep into this, as most pertains to Gasser and race engines which neither of those apply to my Land Cruiser
We know it's flows about 115cfm per square inch. We now can figure out flow per exhaust size using this formula.
Area = π·r2 So area times cfm gives flow.
2.0" exhaust - 361cfm
2.5" exhaust - 565cfm
3.0" exhaust - 813cfm
3.5" exhaust - 1,106cfm
So at this, we can see the factory exhaust will be restrictive at full output and give backpressure issues IF the numbers are correct.
Increased exhaust pressure can have a number of effects on the diesel engine, as follows:
Another online calculator stated I would need 600ish cfm for exhaust flow. That also showed the 4BT as only 500ish.
Donaldson shows 900ish so I really don't know the real answer with just "maths" because I have a lot of conflicting information. Most forums are just a bunch of people arguing over what they think is the right way to figure it...wait that's EVERY forum about EVERYTHING!!! Your intake system needs to flow 1.5 CFM per engine horsepower, and your exhaust system needs to flow 2.2 CFM per engine horsepower is another quick and dirty figure.
From everything I soaked in, 2.5" should be fine, but 3" would be better and have more headroom. In theory, a 2.5" exhaust pipe supports 250HP+ from all the sources I have seen. Thats a whole lot of reading and learning to not really learn a whole lot other than no backpressure on diesel, and free flowing as possible.
In other news the drive in was brutal fog yesterday.
Good thing i got my TEQ Angry Eyes kit installed
A section of straight pipe the length of a typical muffler flows about 115 cfm per square inch.. This is according to David Vizard who wrote books and article on extensive testing of exhaust, flow, pipe size, HP etc. I'm going to not go very deep into this, as most pertains to Gasser and race engines which neither of those apply to my Land Cruiser
We know it's flows about 115cfm per square inch. We now can figure out flow per exhaust size using this formula.
Area = π·r2 So area times cfm gives flow.
2.0" exhaust - 361cfm
2.5" exhaust - 565cfm
3.0" exhaust - 813cfm
3.5" exhaust - 1,106cfm
So at this, we can see the factory exhaust will be restrictive at full output and give backpressure issues IF the numbers are correct.
Increased exhaust pressure can have a number of effects on the diesel engine, as follows:
- Increased pumping work
- Reduced intake manifold boost pressure
- Cylinder scavenging and combustion effects
- Turbocharger problems
Another online calculator stated I would need 600ish cfm for exhaust flow. That also showed the 4BT as only 500ish.
Donaldson shows 900ish so I really don't know the real answer with just "maths" because I have a lot of conflicting information. Most forums are just a bunch of people arguing over what they think is the right way to figure it...wait that's EVERY forum about EVERYTHING!!! Your intake system needs to flow 1.5 CFM per engine horsepower, and your exhaust system needs to flow 2.2 CFM per engine horsepower is another quick and dirty figure. From everything I soaked in, 2.5" should be fine, but 3" would be better and have more headroom. In theory, a 2.5" exhaust pipe supports 250HP+ from all the sources I have seen. Thats a whole lot of reading and learning to not really learn a whole lot other than no backpressure on diesel, and free flowing as possible.
In other news the drive in was brutal fog yesterday.
Good thing i got my TEQ Angry Eyes kit installed
