Repair-It

http://www.lsxtv.com/tech-stories/engin ... pe-ls-v10/

This engine however uses what appears to be a unique manifold. The twin throttle-body design feeds each bank individually. Masters says there is no cross-over within the manifold. This would further aide a displacement on demand system in shutting down one bank of the engine completely, including airflow for anything other than cooling purposes, possibly further improving on performance, emissions, and efficiency when running in DOD mode.

“Our GM sources says that around the time of this engine’s development, GM was looking to get into the V10 market to compete with the Ford pickup V10 and even the Dodge SRT-10 pickup. This engine we are told made 616 horsepower and 789 lb-ft of torque.”

Well this blows my mind for the day.

The LS7 would have been well into its development cycle by this time. I don't really see why they needed this, since the high water mark for BBC power was 340 with the Vortec 8100. Plenty of 6.0 and 6.2L truck engines have exceeded that.

That torque figure is basically impossible though. In LT1 terms, that V10 would need to be 10.75L to make that much torque. I mean 7.5L is only a little bigger than the LS7 and that made like 470 lb-ft.

The LS7 would have been well into its development cycle by this time.

Wait, What?

Let's get off the LS7 high horse, which must come with whip-its or some other brain stopping substance.

The LS7 is: 505 horsepower and 470 lb-ft of torque. I understand that is great, but by todays standards, it is not the be all end all anymore. And at 20K to me it is an over-priced joke. GM has plenty of engines that can hit these stats for much less than 20K. Also, before everyone flips out, I get that for the time that this came out, this was excellent.

Back to the point:

What does that have to do with a 616 horsepower and 789 lb-ft of torque V10? Sorry, if those specs were real, that is an entirely different animal which is why they could have made it. And if they did, everyone would be like LS7 who?

LS7 is the highest output V8, naturally aspirated, that GM ever made.

I made several points.

- Why develop something as exotic as a 7.5L V10 when the LS architecture obviously supported 7.0L? They could have made a truck version out of that. Side note: The 2002 LQ9 was already 5 hp more than a Vortec 8100. I am doubting the stated "need" for this engine.

- There is no way that engine made 789 lb-ft. The LT1 is the current high water mark for torque to displacement and you'd have to scale an LT1 to 10.75L to make that torque. So, no way could a 7.5L Gen III/IV do it, regardless of cylinders. You'd need forced induction, end of story.

- There is no way that "truck" engine made 616 hp if a 7.0L LS7 only made 505, in 2006. The LS7 is expensive because of what it takes to make all that work. I assure you it is cheaper and simpler than a contemporary BMW V10 of similar output. Naturally aspirated power is expensive, in general. Always has been, always will be.

- Why did they need 616 hp to compete with the Triton V10??

Much of this doesn't make sense.

I stand corrected, the engine is now: $16,503.

- Why develop something as exotic as a 7.5L V10 when the LS architecture obviously supported 7.0L?

616 horsepower and 789 lb-ft of torque in a V10.

I agree that if you just extrapolate the cylinders/displacement, it doesn't add up but I am not sure that this V10 would have been the same design with 2 more cylinders, if it was, they probably would have made it since that wouldn't have been to hard to do. Also, if they were trying something more complex and exotic, that is a good reason why they either ran out of money or it wasn't reliable to productionize so it never came to fruition.

Why did they need 616 hp to compete with the Triton V10??

It said they wanted to compete with the RT-10, isn't that the Viper?

The LS7 is expensive because of what it takes to make all that work

Human hands... Two sets.

billgiacheri wrote:I stand corrected, the engine is now: $16,503.

That's fine. I am sure the BMW S85 is substantially more. And wouldn't you know, they have rod bearing problems.
http://www.m5board.com/vbulletin/e60-m5 ... istry.html

$16k is a good deal for what it is. There are cheaper ways to make 500 hp, but not naturally aspirated.

616 horsepower and 789 lb-ft of torque in a V10.

Yes, if that was anything other than pure fiction.

I agree that if you just extrapolate the cylinders/displacement, it doesn't add up but I am not sure that this V10 would have been the same design with 2 more cylinders, if it was, they probably would have made it since that wouldn't have been to hard to do. Also, if they were trying something more complex and exotic, that is a good reason why they either ran out of money or it wasn't reliable to productionize so it never came to fruition.

But that's the thing - it was Gen III/IV engine architecture in a V10 form factor at 7.5L. PROBABLY, it was a way to increase displacement above 7.0L.

It said they wanted to compete with the RT-10, isn't that the Viper?

Yes, but the 2005 Dodge Viper had 500-510 hp...so...where's the fire again?

Human hands... Two sets.

Yes I will grant you the hand built assembly is part of the cost. But the engine has some fancy materials in it, as well.

I don't know why you are giving the LS7 such a hard time. This V10 was supposedly in development and was canceled like 10+ years ago, not last year.

Yes, if that was anything other than pure fiction.

I agree that they seem very optimistic, but if this was really leaked by a GM insider, these seem pretty specific vice 600HP and 800 Ft-lbs. I guess I am saying that if someone is going to leak a story like this with specific numbers, and you believe the V10 part, there must be something to the rating, even if that was the goal, and was never attained. I am just not ready to totally dismiss it as possible. These were GM's dark ages where money was starting to get very tight and they were really failing, so it might have just not been cost effective to produce or even continue looking into. Gas was on the rise, V8's were on the decline as far as demand, and this isn't far from when the Corvette was almost discontinued so I can imagine it would not have taken much to squash this. Too bad.

So HP requires some combination of volumetric efficiency, displacement or RPM. Given the similar architecture and head design, it is totally reasonable to look at the displacement and compare to other LS engines of the era, like the LS7. And if the LS7 originally cost $20k for 505 hp, I think it is obvious that a 616 hp version with only half a liter more displacement, that was supposed to be a truck engine, is just total fiction, unless it was going to cost way more. Fiction in terms of practical possibility, and in terms of not having a need for that engine at that time.

As for the torque, which I actually find more interesting, I found a very useful link on Wiki:
https://en.wikipedia.org/wiki/List_of_a ... perlatives

Specifically: https://en.wikipedia.org/wiki/List_of_a ... ves#Torque

The highest specific torque output is on the 2010 Ferrari 458. It makes a staggering 398 lb-ft from only 4.5L. My LS6 needs 5.7L to make the same torque. Likely this was achieved with very careful attention to intake resonance tuning, and I'd bet this engine does better than 100% VE at its torque peak, which is awesome.

But the point is, 89 lb-ft per liter is STILL only 668 lb-ft at 7.5L, which paints the 789 lb-ft in an extremely unrealistic light. It is just not possible. I have no idea what those numbers mean. It would have to be forced induction. But then, just turbo an existing V8. I continue to challenge this V10. Unless it was a very small group of engineers and when engines like the LS7, LS3, LSA, LS9 and all of the increasingly powerful truck engines kept coming, there was no need for it. The LQ9 literally made the Vortec 8100 obsolete as it was canceled in favor of the Vortec Max branded 3/4 ton engine (a recycled LQ9 from the 2002 Escalade).

GM has settled on 6.2L as the magic number since the 2008 LS3, for whatever reason.

But if you want to get chills:

Also curious is the 7.7 in that stamping. That may also indicate that GM had plans for a slightly larger displacement variant of this engine as well, possibly using a longer stroke.

Hmm, 7.7. You know what 6.2L scaled to a V10 would be? 7.75L.

The Gen III/IV 6.0 has a 4" bore, and scales to the 7.5L V10. The 6.2L has a larger bore, not longer stroke. But they did say "possibly" so maybe it was all bore. Who knows.

The LSV10 appears to be based around the late model LS engine architecture sharing much of its key characteristics with the LS2 and LS7

So exotic architecture is out. Must have been forced induction to come close to those numbers. That would explain the boost in torque.

That is all I can think of. The whole thing is very interesting, but I can see why they canceled it (and have resorted to superchargers after the LS7).