One SLC has been done with a 180 deg set of headers but it was quite involved and increased engine bay temps
SL-C powerplant possibility?
- Thread starter c0wboy
- Start date
The car I mentioned had ceramic coat and header wrap...and fans...and vents cut into the floor of the car to direct air up over and through the engine bay.....not worth the trouble IMHO....we would not make them...
Anything but the traditional 'american v8' rumble.X-merge pipe helps. I have also heard of Dr Gas's Freq mod muffler, but I don't have any experience with any of their stuff. Borla's and Bassani's may also help too.
I've definitely wanted to do something about the sound as well. I have a thought on a header design,, but not sure if it would be rubbish or not, but here is the concept.
What gives V8's it's "rumble" is the double pulses combined with a long pause between firing pulses. Here is the breakdown.
An LS(x) firing order is 1,8,7,2,6,5,4,3
The (*) represent pauses between the pulses
L Bank 1*7**5*31*7**5*3
R Bank 8*26*4**8*26*4*
Now what if you lengthened runners 1 & 7 on the left bank,, and 6 & 4 on the right. They would be considerably longer to compensate for the short exhaust pulse timing between (3 and 1) and (2 and 6). Pretty much trying to make pulses show up at the collector more evenly.
Think about 4 cars showing up at an intersection. Two of them always leave early, so to get them there "on time" you make the road to the intersection a little longer for the early goers, so they all show up properly staggered.
My "guess" would be that (1 & 7) and (6 & 4), would have to have an extra length that would increase the volume of the runners to that of half of the cylinder volume. Another question would be the pros & cons (theorizing here)
Cons:
Header length may not be optimal for all runners to take advantage of the "pulse" scavenging per cylinder cycles.
Pros:
Increase scavenging at the collector because the pulses will arrive more evenly.
I've definitely wanted to do something about the sound as well. I have a thought on a header design,, but not sure if it would be rubbish or not, but here is the concept.
What gives V8's it's "rumble" is the double pulses combined with a long pause between firing pulses. Here is the breakdown.
An LS(x) firing order is 1,8,7,2,6,5,4,3
The (*) represent pauses between the pulses
L Bank 1*7**5*31*7**5*3
R Bank 8*26*4**8*26*4*
Now what if you lengthened runners 1 & 7 on the left bank,, and 6 & 4 on the right. They would be considerably longer to compensate for the short exhaust pulse timing between (3 and 1) and (2 and 6). Pretty much trying to make pulses show up at the collector more evenly.
Think about 4 cars showing up at an intersection. Two of them always leave early, so to get them there "on time" you make the road to the intersection a little longer for the early goers, so they all show up properly staggered.
My "guess" would be that (1 & 7) and (6 & 4), would have to have an extra length that would increase the volume of the runners to that of half of the cylinder volume. Another question would be the pros & cons (theorizing here)
Cons:
Header length may not be optimal for all runners to take advantage of the "pulse" scavenging per cylinder cycles.
Pros:
Increase scavenging at the collector because the pulses will arrive more evenly.
Last edited:
No, he's not. A 180-degree header is an equal-length header. James is talking about an unequal-length header in which the lengths are adjusted so that exhaust pulses arrive at the collector evenly spaced. This won't really work since the necessary differences in primary lengths are a function of engine RPM, so the header will only work as intended at a single RPM.
Mark, I believe you are correct. However, I think it should smooth out the pulses a bit. True, you will only get one RPM where they match perfectly. However, I don't think it will be off as much as one would think. I believe if you look at it as a function of Cylinder emptying volume and speed, it is a matter of how much of the runner get's "filled" up before the next cylinder empties into the runner and exits out into the collector.
Of course, you could avoid all of this, and just make an 8 into 1 exhaust system. I heard an Ultima on youtube that had one and sounded pretty good. Not quite as exotic sounding as a 180 degree system, but more than a rumbling American V8 sound. But then again, it would be almost as complicated to make an 180 degree system.
I would be really interested in seeing if anyone has done this before, or if someone would build something as such.
Of course, you could avoid all of this, and just make an 8 into 1 exhaust system. I heard an Ultima on youtube that had one and sounded pretty good. Not quite as exotic sounding as a 180 degree system, but more than a rumbling American V8 sound. But then again, it would be almost as complicated to make an 180 degree system.
I would be really interested in seeing if anyone has done this before, or if someone would build something as such.
I read for a few hours last night about flat plane crank engines vs cross plane. The flat plane ones just sound amazing and have some benefits with some non, but overall I saw an interest for this and a few different people trying to do it. Now after reading I am wondering a few things.
1- Why has no one stepped up and made a kit. There seems be a little desire for it. Sure it would cost a bit, but that is part of having something inuquie.
2- From what I see you would need these items. Crank and camshaft. You would need to wire the injectors and ignition up a bit different. The spark would not be hard and with wasted spark should not be hard at all. Injectors should be able to be spliced and matched up I would think without a problem so the engine ecu should be the same. Is it really that simple? I would think I am missing something here because if you all you needed was a crank, cam and a little wiring to do it then why has it not been done.
3- I see people wanting to rev a lot and destroking the engines when doing it. I think that adds complexity so if they leave the same con rods and pistons to rev a little higher just the valve train. Mayby SS stronger valves and vavle springs then 8K should be fine.
What I am missing here. If we could have the exotic sound out of an LS3 376 then why has it not been done? If there was a kit I would get rid of my V6 TT idea and do that for sure. The sound of the engine makes the car and experince. Who does not love the sound of an F430 ripping by on track. Truely amazing. I want that bad.
Troy
1- Why has no one stepped up and made a kit. There seems be a little desire for it. Sure it would cost a bit, but that is part of having something inuquie.
2- From what I see you would need these items. Crank and camshaft. You would need to wire the injectors and ignition up a bit different. The spark would not be hard and with wasted spark should not be hard at all. Injectors should be able to be spliced and matched up I would think without a problem so the engine ecu should be the same. Is it really that simple? I would think I am missing something here because if you all you needed was a crank, cam and a little wiring to do it then why has it not been done.
3- I see people wanting to rev a lot and destroking the engines when doing it. I think that adds complexity so if they leave the same con rods and pistons to rev a little higher just the valve train. Mayby SS stronger valves and vavle springs then 8K should be fine.
What I am missing here. If we could have the exotic sound out of an LS3 376 then why has it not been done? If there was a kit I would get rid of my V6 TT idea and do that for sure. The sound of the engine makes the car and experince. Who does not love the sound of an F430 ripping by on track. Truely amazing. I want that bad.
Troy
It has been done. I believe Lingerfelter is testing one out right now. On the dyno it sounds amazing. However...............
With a flat plane crank, you get 1.44 times the vibration of a 4 cylinder with the same stroke and piston weight. The longer the stroke the more vibration. This is caused by the difference in piston speeds of the bottom and top pistons.
If it was just as simple as a billet crank and cam I would have been all over it. It would not cost much more than a 180 degree header system. You would also get the benefit of better scavenging and breathing.
The reason only really high dollar cars have flat plane V8's are as follows:
1. Requires very lightweight reciprocating mass (ie pistons, connecting rods,,ect,,$$$$$$)
2. Engine durablity goes way down, the bearings just can't take the punishment, meaning it would get expensive unless you only drive it 3000 miles a year (like more Ferrari's)$$$$
3. Vibration is hash were the ride would suffer, unless the engine was small. With a small engine you need to rev the heck out of it to get any power and need it to breath really well, meaning variable valve timing, lightweight valvetrain $$$$$$$ again.
It's not a matter of if it can be done. It's a matter of how much you want to spend to get "the sound". With all that spent on it get a V10 or V12 (if it fits), at least you have a lot more durability than a flat plane V8
I don't know how to embred video so here is the link
Lingenfelter 358 CID LSx Flat Plane Crank Engine - YouTube
With a flat plane crank, you get 1.44 times the vibration of a 4 cylinder with the same stroke and piston weight. The longer the stroke the more vibration. This is caused by the difference in piston speeds of the bottom and top pistons.
If it was just as simple as a billet crank and cam I would have been all over it. It would not cost much more than a 180 degree header system. You would also get the benefit of better scavenging and breathing.
The reason only really high dollar cars have flat plane V8's are as follows:
1. Requires very lightweight reciprocating mass (ie pistons, connecting rods,,ect,,$$$$$$)
2. Engine durablity goes way down, the bearings just can't take the punishment, meaning it would get expensive unless you only drive it 3000 miles a year (like more Ferrari's)$$$$
3. Vibration is hash were the ride would suffer, unless the engine was small. With a small engine you need to rev the heck out of it to get any power and need it to breath really well, meaning variable valve timing, lightweight valvetrain $$$$$$$ again.
It's not a matter of if it can be done. It's a matter of how much you want to spend to get "the sound". With all that spent on it get a V10 or V12 (if it fits), at least you have a lot more durability than a flat plane V8
I don't know how to embred video so here is the link
Lingenfelter 358 CID LSx Flat Plane Crank Engine - YouTube
Last edited:
Now that makes sense why they destroke them and talk so much about rod length.
I guess I am going to stick to the v6 twin turbo at 500+ Hp and 8,000 rpm. Fun.
I guess I am going to stick to the v6 twin turbo at 500+ Hp and 8,000 rpm. Fun.
Troy,
What 3.3 are you planning to use specifically? The 3MZ-FE? Any twin turbo ones that you have seen?
This you troy?
http://trueleo.com/SLC.htm
What 3.3 are you planning to use specifically? The 3MZ-FE? Any twin turbo ones that you have seen?
This you troy?
http://trueleo.com/SLC.htm
Last edited:
That is me. 3.3l 3mz-fe. I have seen single turbo ones done, but not a twin so it should be more efficient overall and different than all thr v8's. Plus it is cheap. I am making a custom twin plenum twin throttle body intake that should help with twin turbos and meth injection.
Do you have a link to Dan's build log and/or pics of the engine bay? (I am searching but haven't found it yet) Thanks!
How about for an LS 917? :devilish::devilish::devilish:
I thought about the 1UZ as well.
Pros:
- DOHC means good breathing on top end and the ability to have a high redline due to no pushrods
- Engine itself is cheap, and can be had for ~$400 or so
- Relatively small size and light weight (for a DOHC V8 of that size)
- Good for maybe 400hp without forced induction (if you really tuned the heck out of it)
CONS
- Expensive as hell aftermarket. The pistons and rods alone for a good set will run you as much as a fully forged rotating assembly for an LS(x) engine
- Anything over 400hp you are going to have to use foced induction, which means added cost, complexity, and possibly less reliablity
During the year of planning my build, I've been through a slough of engine possiblities to include:
- Coyote 5.0 (450lbs, DOHC, and can handle 8K rpm out of the box,, however engine is HUGE
- VQ37 (very light 330lbs, 335 out of the box,, and with power adders 500hp is possible without rebuild, Cost about $2,500, tuning an issue because of it's complex variable valve timing. Earlier VQ35 is not near as robust
- EZ30R (very light 330lbs or so, Low CG becaues its a flat 6, perfectly balanced and awesome sound, but aftermarket is sparce and expensive, you can't get any more displacement than 3.0L. The EZ36R is not the same and is much weaker
Other engines I thought about but either price, weight or aftermarket was an issue
BMW V10 (a bit heavier, and probably expensive)
Ford Modular (need to turbo to have any real power, but cheap aftermarket)
Nissan VK45 (Waaay Heavy and no aftermarket)
Pros:
- DOHC means good breathing on top end and the ability to have a high redline due to no pushrods
- Engine itself is cheap, and can be had for ~$400 or so
- Relatively small size and light weight (for a DOHC V8 of that size)
- Good for maybe 400hp without forced induction (if you really tuned the heck out of it)
CONS
- Expensive as hell aftermarket. The pistons and rods alone for a good set will run you as much as a fully forged rotating assembly for an LS(x) engine
- Anything over 400hp you are going to have to use foced induction, which means added cost, complexity, and possibly less reliablity
During the year of planning my build, I've been through a slough of engine possiblities to include:
- Coyote 5.0 (450lbs, DOHC, and can handle 8K rpm out of the box,, however engine is HUGE
- VQ37 (very light 330lbs, 335 out of the box,, and with power adders 500hp is possible without rebuild, Cost about $2,500, tuning an issue because of it's complex variable valve timing. Earlier VQ35 is not near as robust
- EZ30R (very light 330lbs or so, Low CG becaues its a flat 6, perfectly balanced and awesome sound, but aftermarket is sparce and expensive, you can't get any more displacement than 3.0L. The EZ36R is not the same and is much weaker
Other engines I thought about but either price, weight or aftermarket was an issue
BMW V10 (a bit heavier, and probably expensive)
Ford Modular (need to turbo to have any real power, but cheap aftermarket)
Nissan VK45 (Waaay Heavy and no aftermarket)
