Why not direct injection?
Thread Starter
Intermediate
Joined: Jan 2008
Posts: 32
Likes: 0
From: Fremont CA
Why not direct injection?
A lot of manufacturers have started using direct injection in their vehicles. The results seem to be increased mileage and horse power.
GM has used this technology on the CTS.
Is there a reason it isn't being used on the Corvette?
I am not complaining about insufficient power, and the mileage is actually quite good for a V8, but I don't think anybody would say no thank you to more miles per gallon.
I also realize we just got the LS3, so perhaps a future enhancement down the road?
GM has used this technology on the CTS.
Is there a reason it isn't being used on the Corvette?
I am not complaining about insufficient power, and the mileage is actually quite good for a V8, but I don't think anybody would say no thank you to more miles per gallon.
I also realize we just got the LS3, so perhaps a future enhancement down the road?
Le Mans Master
Joined: Apr 2006
Posts: 5,933
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From: The Beautiful Inland Empire WA.
GM is alluding to "exciting upgrades" for the 2010 Corvette........maybe DI for the LS3 could be one of them.....but the way that GM is bleeding $$'s and projected to completely run out of money by this time next year.....any upgrades to any of their fleet are very likely taking a back seat to just plain survival..........
Le Mans Master
Joined: Sep 2008
Posts: 8,022
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From: Stafford VA, home of our wolf den. No house break ins to date.
The Solstice gxp and Saturn Sky Redline (turbo cars) have it... that part of the reason they pump out 260hp and 260ftlbs of torque out of a two liter motor...2.0 thats it.. direct injection.... over 2k lbs per square inch of fuel pressure though...i could here the build up on initial start up..hahaahaqaaa
Melting Slicks
Joined: Nov 2004
Posts: 3,064
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From: Pinellas Park Florida
Well first off the CTS is the darling of GM and it gets all the very best pieces as befits the caddy image. As far as I know the only GM DI is the 304hp, V6 from Australia. The CTS-V gets the current 6.2 with a different super charger set up.
DI would have been a great choice for the Corvette motor with better MPG and, if wanted, more HP. You could reduce the cubic inches and keep the same hp that way you keep it as a V8
DI would have been a great choice for the Corvette motor with better MPG and, if wanted, more HP. You could reduce the cubic inches and keep the same hp that way you keep it as a V8
Last edited by AutoCutter; Oct 29, 2008 at 04:00 PM.
Drifting
Joined: May 2007
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From: Seattle WA
GM, if you are listening, boost the power and MPG for 2010, maybe upgrades the seats, and I'll buy!
Le Mans Master
Joined: Oct 2007
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From: Greater Detroit Metro MI, when I'm not travelling.
Cost. Direct injection adds a fair amount of cost to any vehicle and GM decided they could meet their power and fuel economy goals with the more economical and low tech port injection. Same reason our cars don't have better seats, better paint, a better steering wheel, etc etc... This is a Chevrolet, and a 44,000 dollar one at that; there will always be some compromises.
I hope it makes it to the C7 though... DI is some very neat technology.
I hope it makes it to the C7 though... DI is some very neat technology.
Drifting
Joined: Nov 2004
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From: Cape Canaveral Florida
St. Jude Donor '07 thru '26
NCM Lifetime Member
Eventually, we will probably see DI on all engines ... but it takes time to do the engineering, money to do all the certifications (EPA, reliability, longevity, etc.), and the Vette is pretty far down the pecking order (do the engines you sell the most of first - the V6 and I4s, then trickle to the V8s). The process is far more complex than most people realize ...
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Le Mans Master
Joined: Oct 2007
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From: Greater Detroit Metro MI, when I'm not travelling.
Eventually, we will probably see DI on all engines ... but it takes time to do the engineering, money to do all the certifications (EPA, reliability, longevity, etc.), and the Vette is pretty far down the pecking order (do the engines you sell the most of first - the V6 and I4s, then trickle to the V8s). The process is far more complex than most people realize ...
Carburation<Throttle Body Injection<Port Injection<Direct Injection.
Similarly some day all engines will probably end up with infinately variable valve timing and variable valve lift. When that happens engines will all be making great power figures over 100hp/l with perfect driveabiliy, great gas mileage and low emissions.
And they will be a nightmare to work on
Drifting
Joined: Apr 2008
Posts: 1,759
Likes: 4
From: Texas
I agree... It is the natural progression:
Carburation<Throttle Body Injection<Port Injection<Direct Injection.
Similarly some day all engines will probably end up with infinately variable valve timing and variable valve lift. When that happens engines will all be making great power figures over 100hp/l with perfect driveabiliy, great gas mileage and low emissions.
And they will be a nightmare to work on
Carburation<Throttle Body Injection<Port Injection<Direct Injection.
Similarly some day all engines will probably end up with infinately variable valve timing and variable valve lift. When that happens engines will all be making great power figures over 100hp/l with perfect driveabiliy, great gas mileage and low emissions.
And they will be a nightmare to work on
Melting Slicks
Joined: Aug 2006
Posts: 2,409
Likes: 129
From: Fairview Heights IL
Replacing mechanical cams with computer controlled valve actuators will take a lot of engineering, but the reward will be huge. You'll save a modest amount of weight (no more cams, pushrods, or timing chain), and precisely control hp/torque across a very broad rpm range. Of course, Chuck/CoW will need a much bigger laptop to tune the additional computers.
Le Mans Master
Joined: Aug 1999
Posts: 5,411
Likes: 2
From: N Carolina 08 Z51 Coupe
GM needs a reason for people to upgrade.. In the future.. you will see a smaller displacement V8 using DI to give it more power and meet EPA fuel requirements..
Team Owner
Joined: Sep 1999
Posts: 20,054
Likes: 44
From: Swansea IL
Man that would be sweet, the 3.6L DI V6 that's in the 2LT/RS Camaro I just ordered for the wife has a specific output of 1.4 HP per Cubic Inch. That's more than the LS3/LS7 and only bettered by the LS9.
It's clear to me that DI is the future. Using the 1.4 HP per CI ratio, the current LS3 would be rated at over 525 HP. Sweet.
It's clear to me that DI is the future. Using the 1.4 HP per CI ratio, the current LS3 would be rated at over 525 HP. Sweet.
Last edited by AFVETTE; Oct 30, 2008 at 03:44 PM. Reason: spelling
Team Owner
Joined: Jun 2001
Posts: 26,714
Likes: 344
From: Houston, TX
Well first off the CTS is the darling of GM and it gets all the very best pieces as befits the caddy image. As far as I know the only GM DI is the 304hp, V6 from Australia. The CTS-V gets the current 6.2 with a different super charger set up.
DI would have been a great choice for the Corvette motor with better MPG and, if wanted, more HP. You could reduce the cubic inches and keep the same hp that way you keep it as a V8
DI would have been a great choice for the Corvette motor with better MPG and, if wanted, more HP. You could reduce the cubic inches and keep the same hp that way you keep it as a V8
Melting Slicks
Joined: Nov 2004
Posts: 3,064
Likes: 6
From: Pinellas Park Florida
I agree... It is the natural progression:
Carburation<Throttle Body Injection<Port Injection<Direct Injection.
Similarly some day all engines will probably end up with infinately variable valve timing and variable valve lift. When that happens engines will all be making great power figures over 100hp/l with perfect driveabiliy, great gas mileage and low emissions.
And they will be a nightmare to work on
Carburation<Throttle Body Injection<Port Injection<Direct Injection.
Similarly some day all engines will probably end up with infinately variable valve timing and variable valve lift. When that happens engines will all be making great power figures over 100hp/l with perfect driveabiliy, great gas mileage and low emissions.
And they will be a nightmare to work on
Last edited by AutoCutter; Nov 3, 2008 at 07:34 AM. Reason: Correction
Race Director
Joined: Dec 2007
Posts: 19,030
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From: Maumelle Arkansas
St. Jude Donor '13-'14-'15-'16-'17
Be Happy
Just be glad you have port injection for now.
The added cost and complexity of direct injection is not worth the cost presently. Maybe in the future.
I hope when it does come it's to improve performance and not just a fuel milage band aid and lower performance.
LJ
The added cost and complexity of direct injection is not worth the cost presently. Maybe in the future.
I hope when it does come it's to improve performance and not just a fuel milage band aid and lower performance.
LJ
Race Director
Joined: Oct 2004
Posts: 10,089
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Every diesel engine has direct injection. It is a very old technology, dating back to the end of the 19th century. It is expensive because of the very high pressures involved, and requires precision equipment to service, but it will allow an engine to run a very lean burn, improving MPG at part throttle.
Racer
Joined: Dec 2005
Posts: 363
Likes: 13
From: Dallas TX
Every diesel engine has direct injection. It is a very old technology, dating back to the end of the 19th century. It is expensive because of the very high pressures involved, and requires precision equipment to service, but it will allow an engine to run a very lean burn, improving MPG at part throttle.
Racer
Joined: Mar 2008
Posts: 465
Likes: 0
I seem to remember reading in another thread that DI could not be used in the Vet because of the routing of the intake air. A giant gulp of water in the intake of a DI motor would ruin your day. The low intake of the vet can scoop up a lot of water.