High Output 3.6L

[dwightlooi]

The 3.6L Direct Injected V6 is a fine engine, making between 288 and 304hp is a wide variety of applications while ingesting an unfussy diet of 87 Octane.

However, given that Ford and others have upped the ante on V6 performance, there may be a place for a high output 3.6 to compliment the "Regular" 3.6. This engine shall be targeted at sporty car applications. It is modified for an 18% increase in specific output at the expense of slightly higher costs, a little low end grunt and expects a diet of 91 octane.

Proposed changes:-

• Increased Compression Ratio (11.3:1 --> 12.3:1)
  
• More aggressive cam profiles (increased lift, duration and overlap)
  
• Revised Intake (Larger Throttle Body, Increased air box volume, trumpeted velocity stacks, larger filter area)
  
• Improved Bottom End (Lightened H-section Connecting Rods, Forged Crank, lighter pistons, ladder style main bearing griddles, Piston oil jets)
  
• LF1 (3.0L) style exhaust port (3:1 collector integrated into aluminum cylinder head)
  
• Revised exhaust system (metallic high flow catalysts, larger cross section pipes)
  
• Better Spark Plugs (Iridium Electrode Sparking plugs)
  

Accompanying Transmission Improvements (6L50 --> 6L55)

• Improved Power Rating (315 bhp --> 369 bhp)
  
• Improved Torque Rating (332 --> 345 lb-ft)
  
• Improved Max Gearbox Torque (480 lb-ft --> 521 lb-ft)
  
• Increased Maximum Shift Speed (7000 rpm --> 7200 rpm)
  
• Marginal reduction in Ratio Spread (6.05 --> 5.94)
  

Target Performance:-

Output: 360 bhp @ 7000 rpm

Specific Output: 101 bhp / liter

Torque: 283 lb-ft @ 5800 rpm

Specific Torque: 79 lb-ft / liter

Rev Limiter: 7200 rpm

Fuel Requirement: 91 Octane Unleaded Gasoline

Oil Requirement: 0W-40 Synthetic Oil (Factory Fill --> 0W-40 Mobil 1)

[Z-06]

I am assuming that the fuel economy numbers remain unchanged after this alteration.

How flat will the torque curve be?

[Drew Dowdell]

That would be a wicked one up to Ford if the fuel economy numbers remain the same.

[Carguy]

I like the idea except for fords 365HP Turbocharged 3.7L V6 and its superior Torque advantages. I would just Turbocharge it to 400HP while saving its fuel economy advantage in the process and be more competitive in its Torque #'s. Interesting idea though. I like the way you think!

[dwightlooi]

I like the idea except for fords 365HP Turbocharged 3.7L V6 and its superior Torque advantages. I would just Turbocharge it to 400HP while saving its fuel economy advantage in the process and be more competitive in its Torque #'s. Interesting idea though. I like the way you think!

Well, a turbocharger is not a simple add on either. You have about $500~600 for the turbo alone, the exhaust plumbing to feed it, then you need the IC, the pipings to and from it, etc. Also, turbocharging typically is not fuel economy neutral mainly because you have to drop the compression ratio and go to an intake plenum/runner that doesn't promote cruise efficiency.

An alternative would be a "milder" makeover of the 3.6L DI V6 such as...

Proposed changes:-

• Increased Compression Ratio (11.3:1 --> 12.3:1)
  
• Revised Camshaft Profile (Slight increase in intake duration)
  
• Revised exhaust system (metallic high flow catalysts, larger cross section pipes)
  
• Better Spark Plugs (Iridium Electrode Sparking plugs)
  

Accompanying Transmission Modifications (6L50 --> 6L50E)

• Improved Power Rating (315 bhp --> 325 bhp)
  
• Reduced Input Torque Rating (332 lb-ft --> 312 lb-ft)
  
• Increased Maximum Shift Speed (7000 rpm --> 7200 rpm)
  

Target Performance:-

• Output: 321 bhp @ 7000 rpm
  
• Specific Output: 90 bhp / liter
  
• Torque: 278 lb-ft @ 5700 rpm
  
• Specific Torque: 79 lb-ft / liter
  
• Rev Limiter: 7200 rpm
  
• Fuel Requirement: 91 Octane Unleaded Gasoline
  
• Oil Requirement: 5W-30 Synthetic Oil (Factory Fill --> 5W30 Mobil 1 Extended Performance
  

[Carguy]

If they where to do what you envision it should be the standard engine in the Cadillac line and perhaps the mid range engine in a future Alpha based Camaro. Anything other then those would come up against the far more Torque laden Turbo Ford/Lincoln products. With around 350HP it could be positioned above a Turbo DI 2.0L I4 Alpha based Camaro with 300HP or so horsepower. It would seem to me its usefulness would come into question being its not Torquey enough to compete with the Turbo EcoBoost Ford/Lincoln products in other applications.

[Robert Hall]

I could see such an engine being useful in a CTS Sport model between the regular CTS and the V-series, and maybe in a Camaro between the LT and SS, among other applications. More torque would be good, at least 300 lbft (or 406nm).

[smk4565]

Seems like it would have to rev too much to get power out of it. To me, the 3.6 already lacks power until it gets to around 4,000 RPM. A high revver would work for a sports car or track car, like an S2000 or M3, but in a CTS or especially any of the SUVs, I think the engine needs more low end usable power. I think turbo charging is the way to go. A 3.6 twin turbo with 350 lb-ft at 1800 rpm sounds better than a 3.6 tuned to rev to 7200 rpm.

[dwightlooi]

If they where to do what you envision it should be the standard engine in the Cadillac line and perhaps the mid range engine in a future Alpha based Camaro. Anything other then those would come up against the far more Torque laden Turbo Ford/Lincoln products. With around 350HP it could be positioned above a Turbo DI 2.0L I4 Alpha based Camaro with 300HP or so horsepower. It would seem to me its usefulness would come into question being its not Torquey enough to compete with the Turbo EcoBoost Ford/Lincoln products in other applications.

It really comes down to cost vs benefit. A high revving 3.6 can give GM a clearly class leading NA V6. In fact, even the "modest" version with nothing more than a compression bump, camshaft change and tuning for 91 octane will put the 3.6 in the #2 spot amongst "big" V6 class -- trumping the Ford, Hyundai, Toyota and Mitsubishi 3.5~3.7 liter mills, and fall in in just behind Nissan's 330hp CVVL 3.7 liter on power and beating it on torque. It'll do so without incurring the cost and complexity of a twin turbo setup.

A twin turbo DOHC V6 offers good power, but I am not sure it is more economical than a small block pushrod V8 -- not in terms of fuel economy, not in terms of power-to-weight, not in terms of power-to-size and certain not in terms of simplicity. For instance, the SHO's Ecoboost 3.5 makes 350~355 horses and turns in 17/25 mpg with an automatic tranny. A 6.2 liter small block offers 400~426 hp and turns in 16/24 mpg with an automatic tranny in an SS. Granted the SHO is some 300 lbs heavier and AWD. But it also makes 50~76 less horsepower and is basically FWD until the tires slip.

[Drew Dowdell]

but the 6.2 has pushrods, so it must automatically suck....

[CanadianBacon94]

The 3.6L Direct Injected V6 is a fine engine, making between 288 and 304hp is a wide variety of applications while ingesting an unfussy diet of 87 Octane.

i thought the certified number was 312

[Carguy]

It really comes down to cost vs benefit. A high revving 3.6 can give GM a clearly class leading NA V6. In fact, even the "modest" version with nothing more than a compression bump, camshaft change and tuning for 91 octane will put the 3.6 in the #2 spot amongst "big" V6 class -- trumping the Ford, Hyundai, Toyota and Mitsubishi 3.5~3.7 liter mills, and fall in in just behind Nissan's 330hp CVVL 3.7 liter on power and beating it on torque. It'll do so without incurring the cost and complexity of a twin turbo setup.

A twin turbo DOHC V6 offers good power, but I am not sure it is more economical than a small block pushrod V8 -- not in terms of fuel economy, not in terms of power-to-weight, not in terms of power-to-size and certain not in terms of simplicity. For instance, the SHO's Ecoboost 3.5 makes 350~355 horses and turns in 17/25 mpg with an automatic tranny. A 6.2 liter small block offers 400~426 hp and turns in 16/24 mpg with an automatic tranny in an SS. Granted the SHO is some 300 lbs heavier and AWD. But it also makes 50~76 less horsepower and is basically FWD until the tires slip.

The economy of Turbo engines has been questionable to me since the Nissan 3.0L V6 with 300HP from the old 300ZX when compared to the larger 5.7L V8 245-300HP Vette from the time proved that the Vette was more efficient. So on that point your impression about todays 6.2L V8 would also ring true. But would a high revving 3.6L truly be more efficient then the planned Turbo 3.0L DI V6 GM has planned? I dont know. Its the lack of Torque that bothers me when compared the Ford/Lincoln EcoBoost. Again if there is a place for your higher revving 3.6L it would be as a base Cadillac engine. I would like to see GM do a more unique version of the high feature V6 for Cadillac. Perhaps a unique for Caddy 3.8L version with a non turbo like yours 350HP and a turbocharged 420HP NS V8 replacement. Being the High feature line can and does come in differing sizes why not do unique for each brand version with the best and largest going to Cadillac. In this your plan for a more premium HF V6 could become a reality if GM is listening.

[loki]

i thought the certified number was 312

in the new '11 camaro ...is it that for others?

[CanadianBacon94]

in the new '11 camaro ...is it that for others?

you would think so huh?

[intrigued]

I heard GM was making a twin turbo engine based on the 3.0 HF v6. Any news on that? It should be a very importnt engine to Caddy with all the smaller displacment forced induction engines proliferating through the class.

[aldw]

It really comes down to cost vs benefit. A high revving 3.6 can give GM a clearly class leading NA V6. In fact, even the "modest" version with nothing more than a compression bump, camshaft change and tuning for 91 octane will put the 3.6 in the #2 spot amongst "big" V6 class -- trumping the Ford, Hyundai, Toyota and Mitsubishi 3.5~3.7 liter mills, and fall in in just behind Nissan's 330hp CVVL 3.7 liter on power and beating it on torque. It'll do so without incurring the cost and complexity of a twin turbo setup.

A twin turbo DOHC V6 offers good power, but I am not sure it is more economical than a small block pushrod V8 -- not in terms of fuel economy, not in terms of power-to-weight, not in terms of power-to-size and certain not in terms of simplicity. For instance, the SHO's Ecoboost 3.5 makes 350~355 horses and turns in 17/25 mpg with an automatic tranny. A 6.2 liter small block offers 400~426 hp and turns in 16/24 mpg with an automatic tranny in an SS. Granted the SHO is some 300 lbs heavier and AWD. But it also makes 50~76 less horsepower and is basically FWD until the tires slip.

Wrt luxury vehicles the more important issue is having more exclusivity in the product especially the powertrain and not just the power output,

The market expects high tech

Pushrod OHV engines are not precieved as high tech no matter how good they may be.

Try telling a future Caddy owner that he gets to pay twice as much for what is the same engine as in a truck.

I think you get the idea

A luxury car should have the best Tech and the LS is not - its a good engine but its not high tech

GM has invested zero in combating the perception problem OHV engines have.

Unless GM is willing to invest the time and money to change perceptions (which they don't have), DOHC is the only viable route.

Edited June 21, 2010 by aldw

[regfootball]

It really comes down to cost vs benefit. A high revving 3.6 can give GM a clearly class leading NA V6. In fact, even the "modest" version with nothing more than a compression bump, camshaft change and tuning for 91 octane will put the 3.6 in the #2 spot amongst "big" V6 class -- trumping the Ford, Hyundai, Toyota and Mitsubishi 3.5~3.7 liter mills, and fall in in just behind Nissan's 330hp CVVL 3.7 liter on power and beating it on torque. It'll do so without incurring the cost and complexity of a twin turbo setup.

A twin turbo DOHC V6 offers good power, but I am not sure it is more economical than a small block pushrod V8 -- not in terms of fuel economy, not in terms of power-to-weight, not in terms of power-to-size and certain not in terms of simplicity. For instance, the SHO's Ecoboost 3.5 makes 350~355 horses and turns in 17/25 mpg with an automatic tranny. A 6.2 liter small block offers 400~426 hp and turns in 16/24 mpg with an automatic tranny in an SS. Granted the SHO is some 300 lbs heavier and AWD. But it also makes 50~76 less horsepower and is basically FWD until the tires slip.

SHO 17/25

G8 GXP 13/20

there is a fuel economy difference.

look what happened with the 2.8t when GM said, 'premium only'.....

Edited June 22, 2010 by regfootball

[CanadianBacon94]

SHO 17/25

G8 GXP 13/20

there is a fuel economy difference.

look what happened with the 2.8t when GM said, 'premium only'.....

how much power does a GXP make?

[SAmadei]

how much power does a GXP make?

415 hp. But I have to question the GXP's 13/20 fuel figures. The Camaro is 16/25... a 250lb difference is not going to translate into such a big difference.

I wonder if in the rush to market for the GXP, if a less than optimum gear ratio or programming was used.

Its also interesting to note that the GXP is not listed on fueleconomy.gov.

[smk4565]

A 750iL Hybrid makes 455 hp, 515 lb-ft and gets 17/26 mpg. So maybe GM needs to do something like that. And that car is fat load, that engine could probably get another 1-2 mpg in a lighter car.

[regfootball]

i do know the GXP had a bad mpg rating. but the SHO had equal or more weight and AWD. The SHO yes is slower, so maybe someone can tell me what the G8 GT's mpg was. I do know one road test i read on the GXP G8 they only got like 13 real world mpg.

[dwightlooi]

SHO 17/25

G8 GXP 13/20

there is a fuel economy difference.

look what happened with the 2.8t when GM said, 'premium only'.....

Well, a few things of note here...

The first being that you can skew things significantly wit the choice of gearing. The 6.2 Small Block turns in 16/25 on an Automatic Camaro SS for instance.

The second being that you are looking at about 60 more horses and two more cylinders on the small block so it is not exactly an apples to apples engine comparison.

Overall, there seems to be a difference in fuel economy between DOHC and Pushrod engines of similar output, cylinder count and/or displacement. And, it seems to favor the Pushrod engines. For instance... the 6.2 liter Gen IV Pushrod turns in significantly better numbers than the Mercedes 6.3 liter DOHC V8 (AMG) or the BMW 4.8 liter (N54) NA engines. Better by about 2~3 mpg in city cycle and 3~5 on the highway. Despite perceptions to the contrary, there is a very good reasoning behind this. The Pushrod layout has less valves, less cam lobes, less cams, less bearing surfaces in the valve train. This in general translate to lower frictional losses. They do not have as much valve area and do not breathe as well at higher RPMs. But, engine breathing has practically nothing to do with fuel economy -- at part throttle and at cruise, the engine is making partial power based on an intentionally reduced amount of air actually being aspirated. Any amount of restriction not presented by the intake and valves, is intentionally created by the throttle plate! Similar pumping losses + higher frictional losses means higher consumption, all else being equal.

Reducing displacement in and of itself also sounds better than it actually helps. A 3.0 V6 in the CTS is no more economical than a 3.6 V6. A 1.4 turbo is only 2MPG better in a 38 MPG car than a 1.8 NA while making the same amount of power (albiet a bit more torque), and only with the help of lower rolling resistance tires. This shouldn't be that surprising either. Think about it, same cylinder count, same # of valves and cams means nearly the same frictional loss save of that associated with the very slightly smaller bore. Hence, the gains in frictional reduction is small to begin with. While the turbo brings additional power to make up for the power loss due to displacement reduction, it also brings with it a reduction in compression ratio which hurts cruise economy.

All in all, if you want to build the most economical engine, you'll want the minimum cylinder count, highest compression ratio, the least number of valves and the smallest number of camshafts that will still give you the required output. There are certain contradictions in this in that big bores and lower cylinder count tends to also hurt the maximum compression ratio you can run with a given fuel octane number. For example, a 3.0 liter I-4 for instance with say 11:1 compression on 91 octane, a single overhead cam and 8 valves will be more economical than a 2.5 V6 with quad cams and 24 valves. Another example will be a 1.8 liter 3-cylinder 2-valve SOHC ought to be more economical than a 1.5 or 1.8 liter 4-cylinder. When the objective is all out economy, Honda went for a 1.0 liter three port with 1 cam and 2-valves per cylinder in the original Insight. This is from a company who championed DOHC and cam switching VTEC on their sport compacts at the same time. On the big end of things, we see that a 6.2 liter V8 with 16-valves and 1 cam can be more economical than a 4.8 liter quad cam 32-valve V8. The question is whether you are willing to live with the increased vibrations of having bigger cylinders and fewer of them.

[regfootball]

3 cyl 2 valave engines would never fly here

[Drew Dowdell]

when they're attached to hybrid setups, they might

[67impss]

So the formula for the GEO Metro has merit 3cyl = + MPG's. I really thought GM would go the triple route especially after the Volt was to have one but they 1/2 @$$ it again did well with the I4 but the economy #'s would be much better with I3.

Edited June 26, 2010 by 67impss

[regfootball]

LNF is a smooth motor.

[aldw]

Well, a few things of note here...

The first being that you can skew things significantly wit the choice of gearing. The 6.2 Small Block turns in 16/25 on an Automatic Camaro SS for instance.

The second being that you are looking at about 60 more horses and two more cylinders on the small block so it is not exactly an apples to apples engine comparison.

Overall, there seems to be a difference in fuel economy between DOHC and Pushrod engines of similar output, cylinder count and/or displacement. And, it seems to favor the Pushrod engines. For instance... the 6.2 liter Gen IV Pushrod turns in significantly better numbers than the Mercedes 6.3 liter DOHC V8 (AMG) or the BMW 4.8 liter (N54) NA engines. Better by about 2~3 mpg in city cycle and 3~5 on the highway. Despite perceptions to the contrary, there is a very good reasoning behind this. The Pushrod layout has less valves, less cam lobes, less cams, less bearing surfaces in the valve train. This in general translate to lower frictional losses. They do not have as much valve area and do not breathe as well at higher RPMs. But, engine breathing has practically nothing to do with fuel economy -- at part throttle and at cruise, the engine is making partial power based on an intentionally reduced amount of air actually being aspirated. Any amount of restriction not presented by the intake and valves, is intentionally created by the throttle plate! Similar pumping losses + higher frictional losses means higher consumption, all else being equal.

Reducing displacement in and of itself also sounds better than it actually helps. A 3.0 V6 in the CTS is no more economical than a 3.6 V6. A 1.4 turbo is only 2MPG better in a 38 MPG car than a 1.8 NA while making the same amount of power (albiet a bit more torque), and only with the help of lower rolling resistance tires. This shouldn't be that surprising either. Think about it, same cylinder count, same # of valves and cams means nearly the same frictional loss save of that associated with the very slightly smaller bore. Hence, the gains in frictional reduction is small to begin with. While the turbo brings additional power to make up for the power loss due to displacement reduction, it also brings with it a reduction in compression ratio which hurts cruise economy.

All in all, if you want to build the most economical engine, you'll want the minimum cylinder count, highest compression ratio, the least number of valves and the smallest number of camshafts that will still give you the required output. There are certain contradictions in this in that big bores and lower cylinder count tends to also hurt the maximum compression ratio you can run with a given fuel octane number. For example, a 3.0 liter I-4 for instance with say 11:1 compression on 91 octane, a single overhead cam and 8 valves will be more economical than a 2.5 V6 with quad cams and 24 valves. Another example will be a 1.8 liter 3-cylinder 2-valve SOHC ought to be more economical than a 1.5 or 1.8 liter 4-cylinder. When the objective is all out economy, Honda went for a 1.0 liter three port with 1 cam and 2-valves per cylinder in the original Insight. This is from a company who championed DOHC and cam switching VTEC on their sport compacts at the same time. On the big end of things, we see that a 6.2 liter V8 with 16-valves and 1 cam can be more economical than a 4.8 liter quad cam 32-valve V8. The question is whether you are willing to live with the increased vibrations of having bigger cylinders and fewer of them.

The persistent thing that's bugging GM is that no matter how good technically a pushrod design may be, it will still cost less to sell a DOHC-engine vehicle than a pushrod equivalent thanks to all the momentum the DOHC designs have been getting over the last 20 years, something that GM doesn't have the money or the time to overcome. This is also why I expect Ford to be able to sell more 5.0 V8 equipped vehicles of whatever type compared to their GM counterparts.

Edited June 30, 2010 by aldw

[loki]

3 cyl 2 valave engines would never fly here

http://www.chiefaircraft.com/rcmsec/Models/Engines/Saito/Saito-radials.html

radials... so they prolly do fly!

[dwightlooi]

The persistent thing that's bugging GM is that no matter how good technically a pushrod design may be, it will still cost less to sell a DOHC-engine vehicle than a pushrod equivalent thanks to all the momentum the DOHC designs have been getting over the last 20 years, something that GM doesn't have the money or the time to overcome. This is also why I expect Ford to be able to sell more 5.0 V8 equipped vehicles of whatever type compared to their GM counterparts.

Actually, that may not be the case. Let's put it this way...

There are in general two types of car buyers -- the tech savvy ones and the those that are not.

It is easy to sell technical merit to the tech savvy buyers. Just tell them how your solution is better -- better power to weight, better power to size, better economy, whatever. Most of the time you don't even have to tell them. Bury that marketing in a brochure and they will find it even before your sales guy does.

And then, there are the typical buyer who doesn't even know what DOHC stands for and thinks push rods is something that's part of the door. These types will probably look at the MPG numbers on the stickers and some may go as far as to ask you if it is a "Vee 6". If you tell them it's an I4, they may tell you "Oh, that's cool, just like an iPhone!" But that's about it. They'll go for a test drive, listen for road noise, feel the ride a little and they'll check out the amenitities in the car. How valves are operated in the engine won't come up in the conversation.

For the former, as long as the engine has merit it'll do fine. For the latter, whether an engine has merit or not probably doesn't matter as much as the seat cushions.

Edited June 30, 2010 by dwightlooi

[aldw]

Actually, that may not be the case. Let's put it this way...

There are in general two types of car buyers -- the tech savvy ones and the those that are not.

It is easy to sell technical merit to the tech savvy buyers. Just tell them how your solution is better -- better power to weight, better power to size, better economy, whatever. Most of the time you don't even have to tell them. Bury that marketing in a brochure and they will find it even before your sales guy does.

And then, there are the typical buyer who doesn't even know what DOHC stands for and thinks push rods is something that's part of the door. These types will probably look at the MPG numbers on the stickers and some may go as far as to ask you if it is a "Vee 6". If you tell them it's an I4, they may tell you "Oh, that's cool, just like an iPhone!" But that's about it. They'll go for a test drive, listen for road noise, feel the ride a little and they'll check out the amenitities in the car. How valves are operated in the engine won't come up in the conversation.

For the former, as long as the engine has merit it'll do fine. For the latter, whether an engine has merit or not probably doesn't matter as much as the seat cushions.

There's still the in-between crowd that thinks in terms of HP/L and '4-valves good, 2-valves bad' that is also pretty sizeable and spreads things via word-of-mouth, that's also something that marketing should take into account too.

[dwightlooi]

There's still the in-between crowd that thinks in terms of HP/L and '4-valves good, 2-valves bad' that is also pretty sizeable and spreads things via word-of-mouth, that's also something that marketing should take into account too.

It's relatively easy for that crowd to understand "Horsepower" & "MPG". Even without advertising to this specific regard, when "470hp" & "17 (city) / 26 (hwy) MPG" appears on the same sticker or the same ad, they ought to say "Wow! Really?" You don't really have to talk about camshafts and pushrods until after the fact.