Higher/Same mpg with Heads/Cam? LS1 M6
04-13-2012, 09:08 AM
#21
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I think thats good advice.....and even achieving those goals would be an impressive feat.
Its almost the "FAST, RELIABLE, CHEAP" thing.....(you know the ending....pick two because that's all you will ever realistically have). In the OP's scenario I'm suggesting that he may be forced to pick one or slightly compromise both.
Something has to give because a 346 CID engine capable of 450 to the ground (530 ish at the crank) is going to need the proper valve events to get there and if your forced to keep the valve timing light (for MPG reasons) you are going to need an extremely efficient cylinder head.....a ported stocker wont cut it IMO (port gets too large before it becomes reasonably effective at moving air).
And you should be considering an AFR head if your serious in your quest (or a similar clean sheet design with an efficient small runner). In fact when we were going for our CARB number with the AFR 205's back in 2004, the government agency doing the testing noted that with our heads, not only did the engine produce more power than the stock 243 castings, they also reduced hydrocarbons (burned cleaner) and increased the MPG by a coupe of points in their particular testing (they were impressed actually and shared that with the owner of AFR who passed the info along to me....I was very pleased with that news as you might guess and I was confident it was due to the completely different approach I took in designing it (focusing on a smaller port than stock but a much more efficient higher flowing piece). Some of you may not even realize it but the AFR 205 was THE first aftermarket LS Gen III cylinder head to hit the market.
Anyway, getting back on track, my former 346 which I debuted and used as a promotional vehicle of sorts for that new at the time 205 head, gets close to what your looking for but even that combo, as good as it was, falls short of your lofty goals by a decent amount. However it was actually generating 25-30 more ponies than your target so reducing the cam timing some would have increased the MPG (and hurt power of course) but that should be noted here.
I would have to add that duplicating my combo meant you pretty much threw budget out the window and I worked really hard at completely optimizing that particular package (basically my quest was to make as much power as I could with a smallish 224 cam....MPG wasn't much of a concern but either goal still requires a very efficient engine/driveline). It was an extremely detailed / very optimized build and to this day is arguably the strongest 224 cammed car I have seen.
My Vette would get about 28 - 30 MPG on a straight HWY cruise at 75 MPH or so.....but that's a non stop cruise in light traffic (very little braking and accelerating) on flat tarmac. Not very realistic IMO but it was fun for bragging rights. If I drove it in normal type of situations (some Hwy and some around town stop and go stuff) it would get about 22-24 MPG if I didn't flex the throttle much....if I was in the mood to play it would quickly be in the high teens (still very respectable for a car that would trap 124-125 MPH)
And keep in mind my Vette had everything going for it in the MPG department.....it was (is) a very aerodynamic car with a light clutch, carbon fibre prop shaft, light rims and tires, electric water pump.....all the things you would need to do to get closer to your goals. Truthfully, having spent the better part of my life dedicated to this hobby and the last 10 years or so hyper-focused on Gen III LS engines, my opinion is that your goals are bit unrealistic, even if you had cubic dollars to throw at the project but of course that's just my opinion (although my opinion is based on a reasonable amount of real world experience and the mathematics that drive this hobby).
I should mention compression would help your cause but thats a catch 22 because if you took my combination and shrunk the cam sat six degrees or so (to help out the economy side of the equation and thereby reducing my 475 - 480 RWHP to closer to your 450), the dynamic compression would go thru the roof and you would have a harder time getting this combo to run on pump gas because the DCR would be really high. Big cammed cars you can crank the static up getting close to 12 to 1 because the dynamic compression is still workable on pump fuel due to all the cylinder pressure bled off from the cam overlap. You could run some methanol injection of course.....that would help.
Anyway....I could go on and on. Having done something similar and knowing how many small details were hit to get there, I would say you have you work cut out for you.
The suggestion by "Mr. Sir" which I quoted at the very beginning of this post is a really good one IMO and honestly even those targets would be an accomplishment, but I think those figures are closer to the realm of doable if you have the coin and the determination to see it thru.
I will be rooting for you either way.....its always fun to push the envelope some!
Good luck!
Regards,
Tony
Its almost the "FAST, RELIABLE, CHEAP" thing.....(you know the ending....pick two because that's all you will ever realistically have). In the OP's scenario I'm suggesting that he may be forced to pick one or slightly compromise both.
Something has to give because a 346 CID engine capable of 450 to the ground (530 ish at the crank) is going to need the proper valve events to get there and if your forced to keep the valve timing light (for MPG reasons) you are going to need an extremely efficient cylinder head.....a ported stocker wont cut it IMO (port gets too large before it becomes reasonably effective at moving air).
And you should be considering an AFR head if your serious in your quest (or a similar clean sheet design with an efficient small runner). In fact when we were going for our CARB number with the AFR 205's back in 2004, the government agency doing the testing noted that with our heads, not only did the engine produce more power than the stock 243 castings, they also reduced hydrocarbons (burned cleaner) and increased the MPG by a coupe of points in their particular testing (they were impressed actually and shared that with the owner of AFR who passed the info along to me....I was very pleased with that news as you might guess and I was confident it was due to the completely different approach I took in designing it (focusing on a smaller port than stock but a much more efficient higher flowing piece). Some of you may not even realize it but the AFR 205 was THE first aftermarket LS Gen III cylinder head to hit the market.
Anyway, getting back on track, my former 346 which I debuted and used as a promotional vehicle of sorts for that new at the time 205 head, gets close to what your looking for but even that combo, as good as it was, falls short of your lofty goals by a decent amount. However it was actually generating 25-30 more ponies than your target so reducing the cam timing some would have increased the MPG (and hurt power of course) but that should be noted here.
I would have to add that duplicating my combo meant you pretty much threw budget out the window and I worked really hard at completely optimizing that particular package (basically my quest was to make as much power as I could with a smallish 224 cam....MPG wasn't much of a concern but either goal still requires a very efficient engine/driveline). It was an extremely detailed / very optimized build and to this day is arguably the strongest 224 cammed car I have seen.
My Vette would get about 28 - 30 MPG on a straight HWY cruise at 75 MPH or so.....but that's a non stop cruise in light traffic (very little braking and accelerating) on flat tarmac. Not very realistic IMO but it was fun for bragging rights. If I drove it in normal type of situations (some Hwy and some around town stop and go stuff) it would get about 22-24 MPG if I didn't flex the throttle much....if I was in the mood to play it would quickly be in the high teens (still very respectable for a car that would trap 124-125 MPH)
And keep in mind my Vette had everything going for it in the MPG department.....it was (is) a very aerodynamic car with a light clutch, carbon fibre prop shaft, light rims and tires, electric water pump.....all the things you would need to do to get closer to your goals. Truthfully, having spent the better part of my life dedicated to this hobby and the last 10 years or so hyper-focused on Gen III LS engines, my opinion is that your goals are bit unrealistic, even if you had cubic dollars to throw at the project but of course that's just my opinion (although my opinion is based on a reasonable amount of real world experience and the mathematics that drive this hobby).
I should mention compression would help your cause but thats a catch 22 because if you took my combination and shrunk the cam sat six degrees or so (to help out the economy side of the equation and thereby reducing my 475 - 480 RWHP to closer to your 450), the dynamic compression would go thru the roof and you would have a harder time getting this combo to run on pump gas because the DCR would be really high. Big cammed cars you can crank the static up getting close to 12 to 1 because the dynamic compression is still workable on pump fuel due to all the cylinder pressure bled off from the cam overlap. You could run some methanol injection of course.....that would help.
Anyway....I could go on and on. Having done something similar and knowing how many small details were hit to get there, I would say you have you work cut out for you.
The suggestion by "Mr. Sir" which I quoted at the very beginning of this post is a really good one IMO and honestly even those targets would be an accomplishment, but I think those figures are closer to the realm of doable if you have the coin and the determination to see it thru.
I will be rooting for you either way.....its always fun to push the envelope some!
Good luck!
Regards,
Tony
04-13-2012, 09:09 AM
#22
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I think thats good advice.....and even achieving those goals would be an impressive feat.
Its almost the "FAST, RELIABLE, CHEAP" thing.....(you know the ending....pick two because that's all you will ever realistically have). In the OP's scenario I'm suggesting that he may be forced to pick one or slightly compromise both.
Something has to give because a 346 CID engine capable of 450 to the ground (530 ish at the crank) is going to need the proper valve events to get there and if your forced to keep the valve timing light (for MPG reasons) you are going to need an extremely efficient cylinder head.....a ported stocker wont cut it IMO (port gets too large before it becomes reasonably effective at moving air).
And you should be considering an AFR head if your serious in your quest (or a similar clean sheet design with an efficient small runner). In fact when we were going for our CARB number with the AFR 205's back in 2004, the government agency doing the testing noted that with our heads, not only did the engine produce more power than the stock 243 castings, they also reduced hydrocarbons (burned cleaner) and increased the MPG by a coupe of points in their particular testing (they were impressed actually and shared that with the owner of AFR who passed the info along to me....I was very pleased with that news as you might guess and I was confident it was due to the completely different approach I took in designing it (focusing on a smaller port than stock but a much more efficient higher flowing piece). Some of you may not even realize it but the AFR 205 was THE first aftermarket LS Gen III cylinder head to hit the market.
Anyway, getting back on track, my former 346 which I debuted and used as a promotional vehicle of sorts for that new at the time 205 head, gets close to what your looking for but even that combo, as good as it was, falls short of your lofty goals by a decent amount. However it was actually generating 25-30 more ponies than your target so reducing the cam timing some would have increased the MPG (and hurt power of course) but that should be noted here.
I would have to add that duplicating my combo meant you pretty much threw budget out the window and I worked really hard at completely optimizing that particular package (basically my quest was to make as much power as I could with a smallish 224 cam....MPG wasn't much of a concern but either goal still requires a very efficient engine/driveline). It was an extremely detailed / very optimized build and to this day is arguably the strongest 224 cammed car I have seen.
My Vette would get about 28 - 30 MPG on a straight HWY cruise at 75 MPH or so.....but that's a non stop cruise in light traffic (very little braking and accelerating) on flat tarmac. Not very realistic IMO but it was fun for bragging rights. If I drove it in normal type of situations (some Hwy and some around town stop and go stuff) it would get about 22-24 MPG if I didn't flex the throttle much....if I was in the mood to play it would quickly be in the high teens (still very respectable for a car that would trap 124-125 MPH)
And keep in mind my Vette had everything going for it in the MPG department.....it was (is) a very aerodynamic car with a light clutch, carbon fibre prop shaft, light rims and tires, electric water pump.....all the things you would need to do to get closer to your goals. Truthfully, having spent the better part of my life dedicated to this hobby and the last 10 years or so hyper-focused on Gen III LS engines, my opinion is that your goals are bit unrealistic, even if you had cubic dollars to throw at the project but of course that's just my opinion (although my opinion is based on a reasonable amount of real world experience and the mathematics that drive this hobby).
I should mention compression would help your cause but thats a catch 22 because if you took my combination and shrunk the cam sat six degrees or so (to help out the economy side of the equation and thereby reducing my 475 - 480 RWHP to closer to your 450), the dynamic compression would go thru the roof and you would have a harder time getting this combo to run on pump gas because the DCR would be really high. Big cammed cars you can crank the static up getting close to 12 to 1 because the dynamic compression is still workable on pump fuel due to all the cylinder pressure bled off from the cam overlap. You could run some methanol injection of course.....that would help.
Anyway....I could go on and on. Having done something similar and knowing how many small details were hit to get there, I would say you have you work cut out for you.
The suggestion by "Mr. Sir" which I quoted at the very beginning of this post is a really good one IMO and honestly even those targets would be an accomplishment, but I think those figures are closer to the realm of doable if you have the coin and the determination to see it thru.
I will be rooting for you either way.....its always fun to push the envelope some!
Good luck!
Regards,
Tony
Its almost the "FAST, RELIABLE, CHEAP" thing.....(you know the ending....pick two because that's all you will ever realistically have). In the OP's scenario I'm suggesting that he may be forced to pick one or slightly compromise both.
Something has to give because a 346 CID engine capable of 450 to the ground (530 ish at the crank) is going to need the proper valve events to get there and if your forced to keep the valve timing light (for MPG reasons) you are going to need an extremely efficient cylinder head.....a ported stocker wont cut it IMO (port gets too large before it becomes reasonably effective at moving air).
And you should be considering an AFR head if your serious in your quest (or a similar clean sheet design with an efficient small runner). In fact when we were going for our CARB number with the AFR 205's back in 2004, the government agency doing the testing noted that with our heads, not only did the engine produce more power than the stock 243 castings, they also reduced hydrocarbons (burned cleaner) and increased the MPG by a coupe of points in their particular testing (they were impressed actually and shared that with the owner of AFR who passed the info along to me....I was very pleased with that news as you might guess and I was confident it was due to the completely different approach I took in designing it (focusing on a smaller port than stock but a much more efficient higher flowing piece). Some of you may not even realize it but the AFR 205 was THE first aftermarket LS Gen III cylinder head to hit the market.
Anyway, getting back on track, my former 346 which I debuted and used as a promotional vehicle of sorts for that new at the time 205 head, gets close to what your looking for but even that combo, as good as it was, falls short of your lofty goals by a decent amount. However it was actually generating 25-30 more ponies than your target so reducing the cam timing some would have increased the MPG (and hurt power of course) but that should be noted here.
I would have to add that duplicating my combo meant you pretty much threw budget out the window and I worked really hard at completely optimizing that particular package (basically my quest was to make as much power as I could with a smallish 224 cam....MPG wasn't much of a concern but either goal still requires a very efficient engine/driveline). It was an extremely detailed / very optimized build and to this day is arguably the strongest 224 cammed car I have seen.
My Vette would get about 28 - 30 MPG on a straight HWY cruise at 75 MPH or so.....but that's a non stop cruise in light traffic (very little braking and accelerating) on flat tarmac. Not very realistic IMO but it was fun for bragging rights. If I drove it in normal type of situations (some Hwy and some around town stop and go stuff) it would get about 22-24 MPG if I didn't flex the throttle much....if I was in the mood to play it would quickly be in the high teens (still very respectable for a car that would trap 124-125 MPH)
And keep in mind my Vette had everything going for it in the MPG department.....it was (is) a very aerodynamic car with a light clutch, carbon fibre prop shaft, light rims and tires, electric water pump.....all the things you would need to do to get closer to your goals. Truthfully, having spent the better part of my life dedicated to this hobby and the last 10 years or so hyper-focused on Gen III LS engines, my opinion is that your goals are bit unrealistic, even if you had cubic dollars to throw at the project but of course that's just my opinion (although my opinion is based on a reasonable amount of real world experience and the mathematics that drive this hobby).
I should mention compression would help your cause but thats a catch 22 because if you took my combination and shrunk the cam sat six degrees or so (to help out the economy side of the equation and thereby reducing my 475 - 480 RWHP to closer to your 450), the dynamic compression would go thru the roof and you would have a harder time getting this combo to run on pump gas because the DCR would be really high. Big cammed cars you can crank the static up getting close to 12 to 1 because the dynamic compression is still workable on pump fuel due to all the cylinder pressure bled off from the cam overlap. You could run some methanol injection of course.....that would help.
Anyway....I could go on and on. Having done something similar and knowing how many small details were hit to get there, I would say you have you work cut out for you.
The suggestion by "Mr. Sir" which I quoted at the very beginning of this post is a really good one IMO and honestly even those targets would be an accomplishment, but I think those figures are closer to the realm of doable if you have the coin and the determination to see it thru.
I will be rooting for you either way.....its always fun to push the envelope some!
Good luck!
Regards,
Tony
Btw, I have determination out the ***
04-13-2012, 09:47 AM
#24
Your best bet to increase MPGs and power at the same time is a small twin turbo system, low low gears and weight reduction.
That way you get the power up top when you want it, but while cruising you don't waste anymore gas due to the turbos not producing boost.
A cam and heads will increase airflow at all speeds, so it will kill your MPGs. A turbo will not increase airflow at all speeds, only when it produces boost. So that way you won't hurt mileage when cruising.
Although I will say that anymore than 30mpgs on the highway with a H/C car is going to be unrealistic and hard to achieve. You will be riding around on the chassis and 4 wheels with no body or interior to speak of if you want to achieve 40mpg with those mods. Wouldn't call that a car, that's a big go kart.
That way you get the power up top when you want it, but while cruising you don't waste anymore gas due to the turbos not producing boost.
A cam and heads will increase airflow at all speeds, so it will kill your MPGs. A turbo will not increase airflow at all speeds, only when it produces boost. So that way you won't hurt mileage when cruising.
Although I will say that anymore than 30mpgs on the highway with a H/C car is going to be unrealistic and hard to achieve. You will be riding around on the chassis and 4 wheels with no body or interior to speak of if you want to achieve 40mpg with those mods. Wouldn't call that a car, that's a big go kart.
04-13-2012, 01:38 PM
#25
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The cam may decrease mileage due to slightly lower power production at low rpm. Heads however... The ports are more efficient, as is the combustion chamber, and compression will most likely be higher as well. I think that you think that because they flow more air at WOT they hurt mileage. They CAN flow more, however the throttle is ultimately what controls airflow. Because of the increase in combustion efficiency, you'll actually see a decrease in throttle opening, meaning less air (and fuel) are being consumed.
04-13-2012, 01:53 PM
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All I can say is good luck. I have had several cammed LS cars and none of them have ever gotten more than 28mpg. My G8 with a DOD cam that works with the factory cylinder deactivation would get about 28mpg highway and that was running mainly on 4 cylinders.
04-13-2012, 02:02 PM
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Good luck!
I used to get 30 highway and low to mid 20's city with my intake and cat back 6spd ws6 but even with turbo I doubt you'd get much more than that if any. Maybe if you do a propane mix or cng or something.
Once you up the power to a point you lose your mpg. There has to be a good balance of both.
Again, good luck.
I used to get 30 highway and low to mid 20's city with my intake and cat back 6spd ws6 but even with turbo I doubt you'd get much more than that if any. Maybe if you do a propane mix or cng or something.
Once you up the power to a point you lose your mpg. There has to be a good balance of both.
Again, good luck.
04-13-2012, 03:47 PM
#29
TECH Enthusiast
Build yourself a 10 second car for the weekends, and buy a Civic or such for your commuting needs. You will have your LS1 and 38-40 MPG. I disagree with your 38-40 MPG, and increased power output, being possible for several reasons. Like Tony said, the valve timing events to support your HP goals, will not be good for fuel efficiency. You would need some type of variable valve timing to be able to achieve these goals. You would have better luck with a DOHC engine that you could advance and retard the cams independantly to hit your goals. For example, opening of the exhaust valve, your going to want it to stay closed much longer for efficiency, to get all of the energy out of each "bang" stroke. For performance sake you need to get it open sooner to use that enegry to drive the exhaust out. For efficiency your not going to want any overlap, so unburnt fuel charge doesn't get sucked out the exhaust at low RPM, and for performance you want some overlap to suck charge into the cylinder at higher RPM. Without a way to control these valve events independantly, there is no way to achieve both goals. If you said get 38-40 MPG from an LS1 car, I'd think that difficult but possible. I would run a lean tune, tall gear, improve drag, reduce weight and do some computer modeling to determine best efficiency for valve timing events. Also eliminating the A/C will yeild a little efficiency. You would probably want to put about a 30 MM TB on it to help control the driver input too. One romp to the floor and the MPG average is shot.
I think the AFR heads and a custom cam would be a good choice for both performance and fuel economy. Theoretically a smaller duration cam than stock may yield a little better fuel economy, then you could run a 2.73 as well, and have more torque in the 11-1200 cruise RPM range you will need to keep it to get that type of mileage.
You could also buy an EVO, become a ricer, and get good milage and performance? I say you got 'em smoke em, we won't run out of oil in my lifetime, so anyone have a 6000 SUX forsale?
I think the AFR heads and a custom cam would be a good choice for both performance and fuel economy. Theoretically a smaller duration cam than stock may yield a little better fuel economy, then you could run a 2.73 as well, and have more torque in the 11-1200 cruise RPM range you will need to keep it to get that type of mileage.
You could also buy an EVO, become a ricer, and get good milage and performance? I say you got 'em smoke em, we won't run out of oil in my lifetime, so anyone have a 6000 SUX forsale?
04-15-2012, 04:35 PM
#31
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Launching a man into space was unrealistic at one time. Talking on a wireless telephone was unrealistic. Something unrealistic is just something that hasn't been done yet. Determination is all it takes. One man put hope and determination in the hearts of Americans to push us into space. I am just a mere visionary, and soon, more than that.
04-15-2012, 06:05 PM
#33
What is your budget for this project?
Props if it can be done but after 15+ years of LS engine building and engineering, I simply don't see it happening now. You have one of the brightest LS minds in the world commenting on how even 420rwhp and 35mpg is pushing the limits. Your goals are unfortunately unrealistic.
Props if it can be done but after 15+ years of LS engine building and engineering, I simply don't see it happening now. You have one of the brightest LS minds in the world commenting on how even 420rwhp and 35mpg is pushing the limits. Your goals are unfortunately unrealistic.
04-15-2012, 06:36 PM
#34
04-15-2012, 09:28 PM
#35
Launching a man into space was unrealistic at one time. Talking on a wireless telephone was unrealistic. Something unrealistic is just something that hasn't been done yet.
Space travel was unrealistic due to not having the tech to move something fast enough to fly. Teleporting a human being accross thousands of miles is not something that's unrealistic and we're simply not there yet with technology in order to do it...it's physically impossible. Humans in the 15th century knew that flying was possible (they say birds do it all the time), but they just didn't have the capabilities to do the same. It's not like we can see things being reported all around us and it's just a matter of us finding out how it's done.
While I'm sure that eventually we as humans will develop an engine capable of 450hp and then delivering 40mpgs, we are not in that time yet.
Manufacturers with billions of dollars in reserves and million dollar budget R&Ds have not been able to achieve such a feat in the 100+ years since the automobile has been invented. What makes you think that you will be able to do something that GM or Ford or BMW or MB have not bee able to?
But alas, go head and be this pioneer...we're all going to enjoy watching you try and try and try again...
04-16-2012, 12:39 AM
#36
In a nutshell, the current LS engine design/architecture simply wont support it....my opinion of course. 40 MPG with efficient four valve per cylinder pent roof design four bangers and light cars are barely achieving this.
You would need DOD, and variable valve timing to even get close....it wont happen with a conventional LS set-up.
As these engines evolve it will become more possible but in its current configuration it just wont happen.
May I ask how can you be so sure that you can achieve this??
Do you have any prototype work out in the real world to support your "confidence" for lack of a better word? If so lets hear about it.....if not you might want to back it off a notch and lets just have an open forum discussion on how it might be possible to get close and what you would do in an attempt to achieve impressive yet slightly more realistic goals (say 425 RWHP and an honest 35 MPG.....thats over 500 at the crank and getting 35 MPG at that power level would be extremely impressive IMO).
My .02
-Tony
PS....If you even get to the bogey I just mentioned above with a set of AFR's I will get you a free set of heads but your paying for the first set till you make a believer out of me
You would need DOD, and variable valve timing to even get close....it wont happen with a conventional LS set-up.
As these engines evolve it will become more possible but in its current configuration it just wont happen.
May I ask how can you be so sure that you can achieve this??
Do you have any prototype work out in the real world to support your "confidence" for lack of a better word? If so lets hear about it.....if not you might want to back it off a notch and lets just have an open forum discussion on how it might be possible to get close and what you would do in an attempt to achieve impressive yet slightly more realistic goals (say 425 RWHP and an honest 35 MPG.....thats over 500 at the crank and getting 35 MPG at that power level would be extremely impressive IMO).
My .02
-Tony
PS....If you even get to the bogey I just mentioned above with a set of AFR's I will get you a free set of heads but your paying for the first set till you make a believer out of me
04-16-2012, 09:29 AM
#37
TECH Fanatic
Id be looking at what BSFC the goals were suggesting from the 346 cubes.
You will quickly find that its not possible unless you are thinking way outside the box with direct injection, stratified charge etc.
Maybe with a 4.8L on NOS, 2.7:1 gears, skinny front runners all round, one carbon fibre seat, no carpets, ac etc.
That being said spend a few mins looking at the efilive CAX extentions to allow lean cruise mode. That will get you running 17:1 AFR at cruise if you so desire.
Also whats your budget!?
You will quickly find that its not possible unless you are thinking way outside the box with direct injection, stratified charge etc.
Maybe with a 4.8L on NOS, 2.7:1 gears, skinny front runners all round, one carbon fibre seat, no carpets, ac etc.
That being said spend a few mins looking at the efilive CAX extentions to allow lean cruise mode. That will get you running 17:1 AFR at cruise if you so desire.
Also whats your budget!?
04-16-2012, 09:46 AM
#38
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Id be looking at what BSFC the goals were suggesting from the 346 cubes.
You will quickly find that its not possible unless you are thinking way outside the box with direct injection, stratified charge etc.
Maybe with a 4.8L on NOS, 2.7:1 gears, skinny front runners all round, one carbon fibre seat, no carpets, ac etc.
That being said spend a few mins looking at the efilive CAX extentions to allow lean cruise mode. That will get you running 17:1 AFR at cruise if you so desire.
Also whats your budget!?
You will quickly find that its not possible unless you are thinking way outside the box with direct injection, stratified charge etc.
Maybe with a 4.8L on NOS, 2.7:1 gears, skinny front runners all round, one carbon fibre seat, no carpets, ac etc.
That being said spend a few mins looking at the efilive CAX extentions to allow lean cruise mode. That will get you running 17:1 AFR at cruise if you so desire.
Also whats your budget!?
04-16-2012, 09:47 AM
#39
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In a nutshell, the current LS engine design/architecture simply wont support it....my opinion of course. 40 MPG with efficient four valve per cylinder pent roof design four bangers and light cars are barely achieving this.
You would need DOD, and variable valve timing to even get close....it wont happen with a conventional LS set-up.
As these engines evolve it will become more possible but in its current configuration it just wont happen.
May I ask how can you be so sure that you can achieve this??
Do you have any prototype work out in the real world to support your "confidence" for lack of a better word? If so lets hear about it.....if not you might want to back it off a notch and lets just have an open forum discussion on how it might be possible to get close and what you would do in an attempt to achieve impressive yet slightly more realistic goals (say 425 RWHP and an honest 35 MPG.....thats over 500 at the crank and getting 35 MPG at that power level would be extremely impressive IMO).
My .02
-Tony
PS....If you even get to the bogey I just mentioned above with a set of AFR's I will get you a free set of heads but your paying for the first set till you make a believer out of me
You would need DOD, and variable valve timing to even get close....it wont happen with a conventional LS set-up.
As these engines evolve it will become more possible but in its current configuration it just wont happen.
May I ask how can you be so sure that you can achieve this??
Do you have any prototype work out in the real world to support your "confidence" for lack of a better word? If so lets hear about it.....if not you might want to back it off a notch and lets just have an open forum discussion on how it might be possible to get close and what you would do in an attempt to achieve impressive yet slightly more realistic goals (say 425 RWHP and an honest 35 MPG.....thats over 500 at the crank and getting 35 MPG at that power level would be extremely impressive IMO).
My .02
-Tony
PS....If you even get to the bogey I just mentioned above with a set of AFR's I will get you a free set of heads but your paying for the first set till you make a believer out of me
04-16-2012, 10:47 AM
#40
I need almost no friction from tire to road, extremely light body, no wind running under the car,
So basically you agree that it's physically impossible to do this on planet Earth due to the laws of physics that it experiences, such as gravity, resistance, an atmosphere...