Top Speed R5 with 380 and 430 HP

[thunder550]

Do the new engines have VVT? They could do a lot with that to cut top end power while retaining efficiency. Less air, less fuel, less power but still efficient. I used to mess around with tuning in my old truck, but that was before VVT and DI and all that stuff. Not sure how much of that stuff the newer VPs have.

[slideruleracer]

They have vvt on the cam as a whole, but not on cylinders individually. All gen v's have di and variable cam timing.

But, vvt doesn't change duration and lift, so you're not changing how much air gets into the cylinder.

[Ytmsn]

It's a conspiracy I tell ya. Slide you and Matt are starting to dig down deep and reveal the truth. You both need to start watching for the black helicopters to fly over!

[thunder550]

I'd still put some $$ on timing being the main difference if everything else is the same. Pull some timing, lean it out a little bit and make less power but still get complete fuel burn.

[slideruleracer]

I'd still put some $$ on timing being the main difference if everything else is the same. Pull some timing, lean it out a little bit and make less power but still get complete fuel burn.

Maybe, but then why the change to the fuel system parts? It doesn't make sense that they would bother.. I'm still thinking there's a chance that the fiche has an error and there's really a different cam in it.

[cmattj]

It's a conspiracy I tell ya. Slide you and Matt are starting to dig down deep and reveal the truth. You both need to start watching for the black helicopters to fly over!

[BobRae99]

Doesn't Cobalt publish time to plane, time to speed (various points) and top speed for it's boats with different power? To the OP, I'd look to Cobalt for the numbers. As to the differences between the 380 and 430; maybe it's programming, but until someone looks at all of the part numbers to see what is different, how can you conclude it is only a program change (unless VP has said as much)?

[slideruleracer]

Doesn't Cobalt publish time to plane, time to speed (various points) and top speed for it's boats with different power? To the OP, I'd look to Cobalt for the numbers. As to the differences between the 380 and 430; maybe it's programming, but until someone looks at all of the part numbers to see what is different, how can you conclude it is only a program change (unless VP has said as much)?

Up above you'll see that cmattj did go through the part numbers. Found only changes to ECU and fuel line assembly.

[slideruleracer]

One glaring fact that may give some hints..
We know the engines are the same, we know that the compression ratio is a rather high 11.5 to 1, and both can run 88 octane gasoline. That tells me that both the 380 and the 430 ECU programs have slightly retarded timing programs in order to safely burn regular 87-88 gasoline. I would expect major pre-ignition, but there never is a hint of knock. My wife’s 6.2L gen 5 in her Denali requires 92 octane.. or it will back down timing if the ECU senses knock.
Personally, I would have more respect for the idea of program horsepower if the 430 required premium gasoline.. It doesn’t, which leads to more questions regarding the value of the 430 upcharge.

IMO, I would guess that there is little difference between the two. Simply marketing a 10K upload, a sticker, and an F6 prop to keep the needle watchers happy.
The difference in speed is purely prop. The 380 uses the F5, the 430 uses the F6. The 380 advertises faster plane times than the 430, again prop..
I don’t really know what I have for a program. I do have the F5 prop, and my engine redlines easily to where I can’t leave it wide open..as if being underpropped.

I am sure I could easily squeeze higher speeds with a simple prop change.

Do you know what ECU your engine is running?

[BobRae99]

Doesn't Cobalt publish time to plane, time to speed (various points) and top speed for it's boats with different power? To the OP, I'd look to Cobalt for the numbers. As to the differences between the 380 and 430; maybe it's programming, but until someone looks at all of the part numbers to see what is different, how can you conclude it is only a program change (unless VP has said as much)?

Up above you'll see that cmattj did go through the part numbers. Found only changes to ECU and fuel line assembly.

OK, thanks, but nothing here answers the OPs question. I think contacting Cobalt is the best solution. When I was trying to decide between a 2015 Cobalt 210 with a V8/270 DP and a 2016 Cobalt 210 with a V6/280 DP, I spoke to the Cobalt rep at our local boat show. He pulled out the performance charts which showed top speed was within 2 mph and the V6/280 got on plane .6 seconds quicker than the V8/270. I based my purchase decision on that. I think all of the information here is useful, but in the end, Cobalt has the performance figures and is happy to share them.

[cmattj]

Thought I would drop an email to Volvo . Unfortunately they only allow 250 characters, and I can do that in one breathe.

But here is what I got back. Very interesting.

[BobRae99]

Thought I would drop an email to Volvo . Unfortunately they only allow 250 characters, and I can do that in one breathe.

But here is what I got back. Very interesting.

I'd say it has nothing to do with the EPA. It has more to do with not disclosing trade secrets to the competition. I guess Volvo figures that if the competition wants to know how they are building their engines, they can buy one and tear it apart and then hack into the ECM and read the code.

[Ytmsn]

Well, just to be clear, it doesn't matter if it's a Volvo or Merc, it's a GM motor. Only the components on the outside make it a Volvo or Merc.
Matt, maybe an email to GM would yield better results?

I think the EPA answer is just an excuse and diversion.

[thunder550]

Aren't the ECMs proprietary though? Or are they GM parts as well?

[cmattj]

Well, just to be clear, it doesn't matter if it's a Volvo or Merc, it's a GM motor. Only the components on the outside make it a Volvo or Merc.
Matt, maybe an email to GM would yield better results?

I think the EPA answer is just an excuse and diversion.

In the automotive GM world. Your 6.2 in the Denali 420hp and the 6.2L 455hp in the Corvettes Do have different camshafts entirely, but share the same other top end components including pistons.

I know someone I’ll reach out to and dig further.

Warm up the black helicopters