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ls2 180 degree headers

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Old 11-15-2015, 02:18 AM
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Originally Posted by Van Gui1d3r #838
I'm building the engine to rev high and have very broad power. using stock bore and stroke, stock heads and only throwing in a cam really. heads may get slightly ported more or less port matching it to a good intake
All this and you're using a stock motor with a cam???
Old 11-15-2015, 06:26 AM
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Originally Posted by shtoooobs
Sound like what I'm up to as well, with differences ofcource, blueprinted&drysumped lq4, pair of fresh 317 heads with a custom ground cam, 8into1 headers stuffed into a 95 e34 bmw wagon. I'm scared to rev past 6500 but with proper cam and tune youll see a pretty broad power band.
I went aluminum 6.0 because I need as much weight reduction as possible in my build. I'm actually looking at relocation my radiator to the rear today just to help disperse the weight better in my car. I see 2 pros to this, stock radiator will cool no problems at all because the travel back and forth also will help cool, and ill also get more room up front to get these 180s done.
Old 11-15-2015, 10:30 AM
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If you cut the t top well out and flat sheet metal it over you could get an alum radiator to mount in the back with a remote water pump, run a single -12 feed and return and just tee it off up front to feed both sides in/out, and put one small tank up front as a high point on the shock tower, run the steam lines into it, one line off the return line to the radiator up to it so you can fill there, put a radiator cap also on the same tank, and run an overflow line off it and mount the overflow into he back inside the bumper cover, set it up as a return style, but have the overflow line exit in the back so if it pukes/overflows it doesn't end up on the tires.


Battery and radiator in the back would give you all the room to rout the headers forward and cross them over easily, and a motor/mid plate along with lateral support would easily give routing space for your crossover headers.
Old 11-15-2015, 08:26 PM
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Originally Posted by Blown06
All this and you're using a stock motor with a cam???
I need to buy rods and pistons because I bought a brand new GMPP LS2 block... the rods and pistons will be some kind of aftermarket but yes the heads, crank, gaskets, bearings, and all else internal will be stock. id like to go remote water pump to help relieve the front accessories so the engine can spin up faster. pretty much just run an alternator... that's all that's needed up there...

Originally Posted by JL ws-6
If you cut the t top well out and flat sheet metal it over you could get an alum radiator to mount in the back with a remote water pump, run a single -12 feed and return and just tee it off up front to feed both sides in/out, and put one small tank up front as a high point on the shock tower, run the steam lines into it, one line off the return line to the radiator up to it so you can fill there, put a radiator cap also on the same tank, and run an overflow line off it and mount the overflow into he back inside the bumper cover, set it up as a return style, but have the overflow line exit in the back so if it pukes/overflows it doesn't end up on the tires.


Battery and radiator in the back would give you all the room to rout the headers forward and cross them over easily, and a motor/mid plate along with lateral support would easily give routing space for your crossover headers.
I like the rear mount. I want to run it horizontally over the trunk area and the trunk is already cut out. pusher fans on top and air ducts pulling air from the rear fender area to flow through the radiator and out the bottom to the diffuser and out the back. the line in and the line out, I was thinking to run in aluminum tubing because itll also disperse heat which will also help in cooling.
Old 11-16-2015, 02:24 PM
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Have you looked into anti-reversion cones? I know someone who tried this on a pinto engine and a 428 with good results both times. He tried all this in the late 70s to early 80s before dynos were available to the masses but he was able to use a tighter stall converter with the 428. This is also something that Smokey Yunick experimented with and saw gains from although it's hard to find good information on the topic.
Old 11-16-2015, 06:40 PM
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Originally Posted by greasess
Have you looked into anti-reversion cones? I know someone who tried this on a pinto engine and a 428 with good results both times. He tried all this in the late 70s to early 80s before dynos were available to the masses but he was able to use a tighter stall converter with the 428. This is also something that Smokey Yunick experimented with and saw gains from although it's hard to find good information on the topic.
no I haven't really looked into it. I had some research back in the day on my xs650 about it and never took it anywhere
Old 11-26-2015, 02:51 PM
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There are a few schools of thought for headers beyond the 180 degree deals. I was stuck on 180's for quite some time until I sat down and tried to tailor an outcome. My conclusion is to run whatever headers you want, but try to run a Y-pipe if you can. The flow will even out with a y-pipe of the right size. Nascars have run y-pipes for some time.

These are the mindsets of crossplane headers.
Interpret them how you wish and don't make any math errors.
finding the diameters involve exhaust valve duration, desired V.E.

1: Merge collector with spikes, go straight from primary tube diameter to collector diameter that carries the net flow of the bank. 1.75" primary>3" collector for example.

2: Conical collector. The primary tubes go together to a small diameter collector ring that bears the CFM rating of the two cylinders on the 90 degree interval, and then opens to the collector for the net flow of the bank.

3: 270 degree Tri-Y - Primary tube diameter merges two tubes to a single tube that has a net flow for the two tubes and adjusts them with respect to exhaust valve time open. LS paired cylinders. 1,5 3,7 2,4 6,8.

4: 180 degree Tri-Y split bank - A.K.A. ram horns. Pair 1,7 3,5 2,8 4,6 < nobody makes them this way anymore.

5: Complete 180 headers: If you make complete 180 headers, you are going to take the 1,7 tube and combine it with the 4,6 tube from the above style+ vise versa for the other two tubes.

If you want a flat torque curve for your 6.0, use the LSXRT intake and a cam like the GMPP 226/236-110 cam, but with .580 lift. I'm inclined to say you want a 3.5" y-pipe as close to the collectors as possible that starts at the collector diameter and cones out to 3.5"
Torque = early IVO, early IVC, Late EVO, Early EVC.
Power = early IVO, Late IVC, Early EVO, Late EVC
Old 12-03-2015, 03:14 PM
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Originally Posted by MIKE1444
There are a few schools of thought for headers beyond the 180 degree deals. I was stuck on 180's for quite some time until I sat down and tried to tailor an outcome. My conclusion is to run whatever headers you want, but try to run a Y-pipe if you can. The flow will even out with a y-pipe of the right size. Nascars have run y-pipes for some time.

These are the mindsets of crossplane headers.
Interpret them how you wish and don't make any math errors.
finding the diameters involve exhaust valve duration, desired V.E.

1: Merge collector with spikes, go straight from primary tube diameter to collector diameter that carries the net flow of the bank. 1.75" primary>3" collector for example.

2: Conical collector. The primary tubes go together to a small diameter collector ring that bears the CFM rating of the two cylinders on the 90 degree interval, and then opens to the collector for the net flow of the bank.

3: 270 degree Tri-Y - Primary tube diameter merges two tubes to a single tube that has a net flow for the two tubes and adjusts them with respect to exhaust valve time open. LS paired cylinders. 1,5 3,7 2,4 6,8.

4: 180 degree Tri-Y split bank - A.K.A. ram horns. Pair 1,7 3,5 2,8 4,6 < nobody makes them this way anymore.

5: Complete 180 headers: If you make complete 180 headers, you are going to take the 1,7 tube and combine it with the 4,6 tube from the above style+ vise versa for the other two tubes.

If you want a flat torque curve for your 6.0, use the LSXRT intake and a cam like the GMPP 226/236-110 cam, but with .580 lift. I'm inclined to say you want a 3.5" y-pipe as close to the collectors as possible that starts at the collector diameter and cones out to 3.5"
Torque = early IVO, early IVC, Late EVO, Early EVC.
Power = early IVO, Late IVC, Early EVO, Late EVC
you seem to know a thing or two. care to explain your background a bit?
Old 12-07-2015, 06:10 PM
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I'm a senior engineering student.
Don't build what you can buy is my mentality.
Spark notes: You need AFR 230 heads, and a 228/232 112+7 .581/.581
Your engine is going to blow up at 6800 on those stock rod bolts.

General rule of thumb for cams. You lose 60 degrees of duration to normalize at you advertised flow number. This accounts for low lift flow.
A good engine with 10.5:1 compression can definitely make 72 lbft per liter.

Close your valve at about 45 degrees bottom dead center, open it between 14 and 7 degrees before top dead center. That gives you a 239 cam with a ton of valve overlap that messes up your idle. But if your car came stock with a 204 cam, it's a battle of 179 and 144. The 239 will flow you 24.3% higher on the intake side. The thing is that the engine at a lower speed, takes longer to flow with more cam in it. That's your bottom end loss. So, you need middle ground. That's why folks pay me to think and doubt myself to generate a solution.

If I crack out some software that folks don't seem to appreciate, I can reverse engineer your engine. 3.622" stroke, approx 4" bore, 6.098" rod. 1.331" piston. 260 cfm heads. With a 204 cam that closes 39 degrees after bottom dead center. Your engine is breathing its deepest at 4200. When you spin it higher so it has latency from the combustion chamber and 10% volume loss in the 39 degree intake valve closing, the engine is admittedly at its air limit at 5100. Spin it harder, so it exceeds the available flow by 10% again and that engine just won't pull at 5600 like it did at 4K. Give it 24% more usable cam before you run the engine dead out of air and it'll pull hard to 6000. It's out of air at 6600, and you can wing it higher to 7K, but your rod bolts and valvetrain were never meant to go there. Your engine will make 494 crank at 6000 rpm. 239 cam. Your torque at 2800 will be under 300 lbft. 475 lbft peak, 4800. Your low end torque is dead.

You need ported heads in the 310 CFM range @ .551 so that you don't need a 240 cam to get better volumetric efficency. That's why GMPP runs that ASA cam in the ls3 crate. flatter torque curve. A more responsive build would be 234/258 108+8, but that will idle at 2K. Welcome to engineering.
Old 12-07-2015, 07:27 PM
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Let's look at pipe flow. Generally, its 100 CFM per square inch, at 1 PSI. What does 1.75" primary do (1.875 O.D., .0625" wall")? 2.4 square inches, 240 CFM. Since your engine throws about half of its energy out the exhaust, the least it could do is use that to give us about a 1.5 psi pressure differential so we can flow a crap exhaust port with wasted heat, and let us run a good intake valve.
If you make some tri-y headers, there are two options:
1: Don't mess up the CFM rating and keep the flow constant,
2: Or solve a vibrations problem.
I don't know much about air vibration, so CFM it is.
The pipe is flowing twice as much air half of the time. Do we get a bigger pipe? We would need 2.5." pipe. It's still running half of the time though, so why not just run the 1.875" pipe at full duty cycle? Well, there's a 5 unit wait time and a 3 unit wait time from the center of one cylinder to the other. What if we double the flow capacity, and then run 3/5 as much pipe? 20% more flow? 1.91" pipe. Just run 2" o.d. and call it a day? Hell with it.

The collector pretty much sees one cylinder at a time, except for this spot where two cylinders are on top of each other. They run 50% longer than normal at twice the flow. I need 30% more flow for sure. I started with 2" pipe, so I go bigger I guess. I need a 2.375" pipe I guess, or should I make it flow four times the flow? Four times the flow is 3.5" pipe at half cycle. What about four times the flow at 75% cycle? 3" collector? Cutting and welding different sizes is gonna suck. It works however I want. I guess I could merge the 2" pipes to 2.5" collector that cones out to 3"

Why should I run a y-pipe? Well, I don't really know for sure, but I do know that it will see a fresh cylinder at an even interval. None of this 180, 270, then almost two at the same time business. Eight times the flow, half the duty freedom, and maybe 5% more, because hell, you saw how complicated this was. 3.5" pipe. You could probably bolt up 3" and not notice much of a difference by the time the air volume has cooled down from the headers. Plumb it into a 30" long magnaflow and 45 it out in front of the rear tire. Any more, and we're gonna have a ton of work, blown cash, complicated car, for a problem we solve better with bolt-on ported heads and some headers we can buy. On paper, I just said it would make 500hp. Why not?
Old 12-08-2015, 03:14 AM
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Originally Posted by MIKE1444
I'm a senior engineering student.
Don't build what you can buy is my mentality.
Spark notes: You need AFR 230 heads, and a 228/232 112+7 .581/.581
Your engine is going to blow up at 6800 on those stock rod bolts.

General rule of thumb for cams. You lose 60 degrees of duration to normalize at you advertised flow number. This accounts for low lift flow.
A good engine with 10.5:1 compression can definitely make 72 lbft per liter.

Close your valve at about 45 degrees bottom dead center, open it between 14 and 7 degrees before top dead center. That gives you a 239 cam with a ton of valve overlap that messes up your idle. But if your car came stock with a 204 cam, it's a battle of 179 and 144. The 239 will flow you 24.3% higher on the intake side. The thing is that the engine at a lower speed, takes longer to flow with more cam in it. That's your bottom end loss. So, you need middle ground. That's why folks pay me to think and doubt myself to generate a solution.

If I crack out some software that folks don't seem to appreciate, I can reverse engineer your engine. 3.622" stroke, approx 4" bore, 6.098" rod. 1.331" piston. 260 cfm heads. With a 204 cam that closes 39 degrees after bottom dead center. Your engine is breathing its deepest at 4200. When you spin it higher so it has latency from the combustion chamber and 10% volume loss in the 39 degree intake valve closing, the engine is admittedly at its air limit at 5100. Spin it harder, so it exceeds the available flow by 10% again and that engine just won't pull at 5600 like it did at 4K. Give it 24% more usable cam before you run the engine dead out of air and it'll pull hard to 6000. It's out of air at 6600, and you can wing it higher to 7K, but your rod bolts and valvetrain were never meant to go there. Your engine will make 494 crank at 6000 rpm. 239 cam. Your torque at 2800 will be under 300 lbft. 475 lbft peak, 4800. Your low end torque is dead.

You need ported heads in the 310 CFM range @ .551 so that you don't need a 240 cam to get better volumetric efficency. That's why GMPP runs that ASA cam in the ls3 crate. flatter torque curve. A more responsive build would be 234/258 108+8, but that will idle at 2K. Welcome to engineering.
Typical engineer ****. When real world results makes what you wrote on paper seem stupid as ****.
Old 12-08-2015, 07:07 PM
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now how does this play into the 180 degree headers?
Old 12-08-2015, 08:56 PM
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https://ls1tech.com/articles/lingenf...g-to-9000-rpm/

https://ls1tech.com/forums/generatio...ls1-build.html

was 2012 but a flat crank was only $2500, leaves you enough room for the cam, and headers, and you have a way way easier build
Old 12-08-2015, 10:18 PM
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Originally Posted by Blown06
Typical engineer ****. When real world results makes what you wrote on paper seem stupid as ****.
You're right dude. My calculations say a 6.0 with 243 heads and a 239 cam is a build that makes 494 crank with a soft bottom end. Anybody know what that kind of build actually does? The only 239 cam off the shelf I know about is the MS4 239/242.
Old 12-08-2015, 10:34 PM
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Originally Posted by Van Gui1d3r #838
now how does this play into the 180 degree headers?
In a nutshell, it's a ton of work and it's not gonna feel like it was worth it.

We could actually sit here and look at the thermodynamics and harmonics of 180 headers, and come up with tuned tubes like 32" long and with diameters of 1.75" to make a high revving 6.0, and to check it, we could fire up Star CCM, and Ansys, and Flo-Works, and solve the same Ordinary Differential Equation with 100 different tweaks, but just a rinky dink numeric approximation in Excel says it's not worth our time.

The 180 headers won't have a magical effect that makes them so much better compared to a well executed cam/long tube/x-pipe build with ported heads and the LSXRT intake, or just an L76/gmppL92 head swap and an itty bitty 216/228 cam. Don't get me wrong, I love the sound of flat plane cranks, but those engines are way different. 12.5:1 compression with heads that smoke nascar heads at low lift, and they're able to phase valve events, versus my feeble attempt at cranking up the duration just so we have a larger lift curve.
Old 12-09-2015, 08:53 AM
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Me thinks Mike1444 likes to hear himself talk...or type...
Once you graduate and get into real world where things don't act they "should" or you think some software told you it should it will be interesting.

And as far as this "don't build what you can buy" comment....what a line of bullshit. I understand the view that sometimes certain things are not worth building due to the cost/benefit ratio...but jesus being in engineering you are just lazy.

You are an engineer I could not stand being in the same room with since you seem to have no outside the box thinking due to your comments in here.

Hell, even if they don't work or make no more power than off the shelf headers, then OP can say he built something different that not too many people can handle. If everyone thought like you then everyone would ASSUME that the vendors made the best possible solution to any given problem...which is not the case.

End rant. Pisses me off when people that have their head buried so deep in virtual reality/CAD that they **** on other that want to actually research/fabricate something.
Old 12-09-2015, 09:22 AM
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All you engineer haters:
get out of your car, throw away your smartphones, take off your shoes and clothes, and walk...

( there are already too many damn arts graduates in the world already )
Old 12-09-2015, 09:28 AM
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"don't build what you can buy" is not a reference to being lazy (why don't you build yourself a cross plane crankshaft, you'll surely have bragging rights), but is a reference to utilizing someone else's specialized knowledge implemented in the product they're selling.
Old 12-09-2015, 05:59 PM
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Originally Posted by MIKE1444
In a nutshell, it's a ton of work and it's not gonna feel like it was worth it.

We could actually sit here and look at the thermodynamics and harmonics of 180 headers, and come up with tuned tubes like 32" long and with diameters of 1.75" to make a high revving 6.0, and to check it, we could fire up Star CCM, and Ansys, and Flo-Works, and solve the same Ordinary Differential Equation with 100 different tweaks, but just a rinky dink numeric approximation in Excel says it's not worth our time.

The 180 headers won't have a magical effect that makes them so much better compared to a well executed cam/long tube/x-pipe build with ported heads and the LSXRT intake, or just an L76/gmppL92 head swap and an itty bitty 216/228 cam. Don't get me wrong, I love the sound of flat plane cranks, but those engines are way different. 12.5:1 compression with heads that smoke nascar heads at low lift, and they're able to phase valve events, versus my feeble attempt at cranking up the duration just so we have a larger lift curve.
it may be a ton of work but I can do it and I want to. that enough reason for me. I like the sound, I like the fact that there are more people opposed to it then for it, and I think there is so much more too them then people believe. if not its my loss.

I just want the pros and cons and the gains or losses. that's the point of this thread.

Originally Posted by smitty2919
Me thinks Mike1444 likes to hear himself talk...or type...
Once you graduate and get into real world where things don't act they "should" or you think some software told you it should it will be interesting.

And as far as this "don't build what you can buy" comment....what a line of bullshit. I understand the view that sometimes certain things are not worth building due to the cost/benefit ratio...but jesus being in engineering you are just lazy.

You are an engineer I could not stand being in the same room with since you seem to have no outside the box thinking due to your comments in here.

Hell, even if they don't work or make no more power than off the shelf headers, then OP can say he built something different that not too many people can handle. If everyone thought like you then everyone would ASSUME that the vendors made the best possible solution to any given problem...which is not the case.

End rant. Pisses me off when people that have their head buried so deep in virtual reality/CAD that they **** on other that want to actually research/fabricate something.
I like your thinking. pretty damn harsh in the way you said it but its your attitude that keeps things moving forward.

still could've been a bit nicer though... a healthy debate isn't a bad thing(pain in the *** against an engineer sometimes)...


Originally Posted by joecar
All you engineer haters:
get out of your car, throw away your smartphones, take off your shoes and clothes, and walk...

( there are already too many damn arts graduates in the world already )
I'm not a hater, but as a CNC Machinist programmer, ive had my doubts in what goes on in "some" engineers heads

and before you come back at me for that, I have had a few moments where ive had to "correct" designs, and thought processes of the "higher educated".

Originally Posted by joecar
"don't build what you can buy" is not a reference to being lazy (why don't you build yourself a cross plane crankshaft, you'll surely have bragging rights), but is a reference to utilizing someone else's specialized knowledge implemented in the product they're selling.
remember, the best can only get better.

and I could, turn a flat plane crank... but id rather do 180 degree headers because you cant buy them for my car but I can buy a flat plane crank...


now if everyone would stop with the pissing match and either leave the thread or get back on task to the 180 degree headers. I don't want to hear why I shouldn't, but why I should.
Old 12-09-2015, 07:03 PM
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VG#838:

I wasn't aiming at you, you're trying to keep this on track, I was aiming at the other two.

Correcting of engineers, I don't doubt it, higher education doesn't waive smarts
(and conversely, there are higher educated smart people out there).

If you can fabricate headers, then by all means proceed... there'd be a very interesting learning curve regarding the specific details such as diameters, lengths, merges, tuning/harmonics, space constraints... I imagine someone going several iterations.

Another good example of 180 degree headers in a mid-engine car is the Ford GT40 with the FE 427.


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