Next generation GM V-8?

[BRAAP]

I may be a bit behind the modern automative informational times not having any C&D, MT, R&T or AW subscriptions any more, forgive me is this old news.

 

Is there any truth to this, other evidence, etc... GM's new flag ship V8?... More details please... .

 

http://www.autoblog.com/2010/06/29/report-next-chevrolet-corvette-to-get-440-hp-5-5-liter-v8/

[Zmanco]

I get C&D and R&T and don't remember seeing this. The power to displacement ratio goes up by 15% based on their numbers if I did the math right. I believe the Mercedes 4 valve 5.5 L V8 is rated around 380 HP so 440 from 2 valves is pretty impressive.

 

Of course, I'm assuming they're staying with 2 valves per cylinder. Would it be possible to go add a third for intake with only 1 cam? Hope that's not a stupid question - I know next to nothing about GM V8s.

[260DET]

For any sort of mass produced road car anything more than a two valve pushrod or SOHC motor is just wasteful marketing nonsense. The multi valve engines gained an advantage because they were competing against old technology that had not had anywhere near the same R&D put into them, the LS engines are putting that right.

 

Only thing is the Corvette engine should be turbocharged, not supercharged which is relatively inefficient and panders to the lazy 'I can't be bothered changing gear' lot. Get a bloody auto.

[78 LS2 Z]

 

Only thing is the Corvette engine should be turbocharged, not supercharged which is relatively inefficient and panders to the lazy 'I can't be bothered changing gear' lot.

 

I think in the Vette's case this is all to do with packaging. Intercooling packaging is easier too with the charger. Sure, these are relatively inefficient but they tend to be easier to tune and are less fickle than the turbo setups. Heat is a big issue too. Point is that you can make a good case for either power adder and the point of "relative" inefficiency of a supercharger is made moot by simply spinning the thing to get the desired power level. Ask the top fuel guys if they feel supercharger efficiency is an issue. I don't think either is superior to the other, just different.

[SUNNY Z]

I would say the supercharging vs turbo on the 'Vette has to do with drivability as well. With the tall gears the vette has, being a dog down low would make it a real turd to drive. Plus, when the engine hit boost (turbo), it would likely come on very violently, causing loss of traction, and / or control. Seeing how these cars were designed to be road raced, it is less than ideal to have to brake boost through the corner inorder to have a scorching exit speed. Just my opinion, I've been wrong before.

Edited July 16, 2010 by SUNNY Z

[FlatBlack]

That concept car makes me want to claw my eyes out.

 

I'd agree with the 'hitting boost' comment. The S/C has a smoother, more predictable power delivery. And who needs more than 640WHP in a factory car, anyways??

[78 LS2 Z]

That concept car makes me want to claw my eyes out.

 

I'd agree with the 'hitting boost' comment. The S/C has a smoother, more predictable power delivery. And who needs more than 640WHP in a factory car, anyways??

 

I'd like more power, but I also need therapy. Yup, even with a centrifugal supercharger it's pretty steady. My YSi trim vortech in my Stang has a power and torque curve that is instant and straight across the paper, no matter what RPM you start the pull. If it were a cardiogram the patient would be very dead...... Try that in a turbo. In fact, my torque and power are nearly identical at every part of the powerband, you almost can't tell which line is which...Makes for a very predictable, consistent and satisfying car. Once you get to a certain power level (and any power level to a point), predictable is a very good and necessary thing IMO.

 

Anyways, back to the point- I think you are right, you don't see V8 turbos in OEM applications for a reason. Superchargers are a blast. I used to own an 01 Lightning that was a real hoot.

[GOTHALOSISM]

Thats the Stingray concept, it was in the last Transformers movie. I was able to see it at the Denver autoshow and it was quite interesting to say the least.

[nullbound]

I get motor trend and saw the source article that the autoblog link is referring to:

 

http://www.motortrend.com/features/auto_news/2010/1008_corvette_to_get_all_new_small_block/index.html

 

I haven't seen anything else on this, though.

[Aaron D]

The boys at GM tried a Turbo in the '09 ZR1. The reason they didn't go with it is because they don't know how to build a turbo'd sports car. They burned it to the ground: http://www.automobilemag.com/reviews/chevrolet/0802_2009_chevrolet_corvette_zr1/index.html

 

They just gave up on it and went with the easy way out with the super charger, probably because it seemed the safer route too since it didn't burn the car down either, a few liabilities there I'm sure.

 

 

 

This argument between the Centrifugal S/C and Turbo is really a moot point since the Centrifugal is basically a belt driven turbo, the exhaust driven turbo could be sized to give a performance/power curve very nearly the same as the belt driven one with improved MPG's since there is less parasitic drag on the engine. The upshot of if GM HAD used a turbo set up would have been aftermarket tuneability, upsizing turbos etc.

 

Now if GM had used a screw or roots style S/C, then there would be much more room for argument. Performance characteristics of Positive displacement Superchargers are worlds apart from Centrifugal.

[FlatBlack]

Now if GM had used a screw or roots style S/C, then there would be much more room for argument. Performance characteristics of Positive displacement Superchargers are worlds apart from Centrifugal.

 

Are you saying they are using a centrifugal S/C on the LS9/LSAs?

 

 

 

 

That looks like a 'Roots-style' to me.

 

The article you linked even stated it had a roots type blower:

 

THE ENGINE

 

The star of the underhood team is a Roots-type supercharger manufactured by the Eaton Corporation. Carmakers have used the supercharging gambit for more than a century because it works: when you blow more air into an engine, more power comes out.

Edited July 20, 2010 by FlatBlack

[Aaron D]

Sorry, I got caught up in my Centrifugal thoughts with "78 LS2 Z", no the LS9 has the roots style for sure.

[78 LS2 Z]

 

 

This argument between the Centrifugal S/C and Turbo is really a moot point since the Centrifugal is basically a belt driven turbo, the exhaust driven turbo could be sized to give a performance/power curve very nearly the same as the belt driven one with improved MPG's since there is less parasitic drag on the engine. The upshot of if GM HAD used a turbo set up would have been aftermarket tuneability, upsizing turbos etc.

 

Now if GM had used a screw or roots style S/C, then there would be much more room for argument. Performance characteristics of Positive displacement Superchargers are worlds apart from Centrifugal.

 

My point has nothing to do with the type of supercharger, it is the argument of a turbocharger vs. a supercharger. My centrifugal comments were nothing more than an example of how good a supercharger can be. The GM supercharger is not a centrifugal supercharger, it is a positive dispacement supercharger. As far a there being room for argument, there is simply no cut and dry answer to which is better. Merely stating that the centrifugal is just a belt driven turbo is far from accurate. There are many more parts with a turbo setup and parts break. Ask any tuner what is easier to tune and the centrifugal blower will usually take the nod. Either can be made in a more favorable light given the purpose of your build.

 

As far as the aftermarket tunability and upgrading goes, ever heard of a cog? Custom tunability is not optional with a turbo, it's mandatory and you better know what you are doing. Optional is not bad, it's good. My YSi centrifugal blower puts 750hp to the wheels with a bone stock Mustang 89 processor, tuned through a timing light, fuel pressure and injector only. Would you rather be at your laptop figuring out a tune after every run or shut the hood, forget about it and race? I have hundreds of passes with this combo and zero issues. It hasn't been on a dyno since the base tune 3 years ago. That's on a slipping 8 rib belt too, no cog.