L92 Truck Engine - - Perhaps ????

[RustyJC]

Dieselclacker,

From my earlier post:

So, if the engine designers wish, they could supercharge this engine and achieve the same ~400 BHP at a lower RPM (N) with a higher torque (related to P) which would make this engine's performance characteristics more comparable to large displacement naturally aspirated gasoline engines. This higher BMEP does require beefier internal components, however - think diesel engine component design.

Rusty

[dieselclacker]

Rusty,

I agree completely with your prior "diesel beef" statement, just putting in my two cents.

Dieselclacker

[tderonne]

You don't have to wonder what a supercharged L92 would look like.

It's an LSA as seen in the Cadillac CTS-V. Here's the flyer for the marine version:

http://http://www.marinepowerusa.com...MarineBase.pdf

[DriVer]

Try this it works better

Oh My goodness ...... 540 by 540 awesome!

It's my opinion that at the end of the day here, we're going to see some type of supercharged Lx engine variant in our Workhorse motorhomes in 2011 and beyond!

[motohomer]

Here are the 2010 specs:
http://www.gm.com/experience/technol...LSA_Marine.pdf

Note the 'official' power numbers are with 93 octane. Premium required.

It also states E85 compatibility. E85 has a bit less power, but a higher octane rating, so in this instance there could be real cost benefits as E85 is much cheaper than premium.

We could get into a whole discussion on increasing the stroke and lowering the compression to move the power curves (flatten the low RPM torque) and allow for 87 octane. But the EPA NOx regs will probably prevent that.

A flat 500 lb-ft, with a 400 HP peak at under 4500 RPM, and 200 HP on tap at ~2200 RPM would suit most of us fine.

The normaly aspirated 6.2 puts out about 400 HP & 400 lbft. Albeit at almost 6000 RPM. Thats sufficient for all but the biggest W22's at a much lower cost. Here is a link:
http://archives.media.gm.com/us/powe...ilveradoLT.pdf

Anybody know if the EPA marine regs are the same as the on-highway regs? I find the EPA site to be one big marketing campaign without any actual regulations listed.

[RustyJC]

One factor to remember about marine engines - they have an infinite supply of cool water for engine, lube oil and charge air cooling. That's why marine ratings of all manufacturer's engines are higher.

Rusty

[tderonne]

The CTS-V version is rated at 556 HP and 551 ft-lbs. The ZR1 Corvette version, the LS9, is rated at 638 HP and 604 ft-lbs. A real marine rating, with a really cold (lake water cold) would be even higher. The 540/540 is a pretty conservative number, something like what a truck version would be, if GM was in the medium duty truck market anymore.

[RustyJC]

Apples and oranges. What I'm saying is that, if you take the marine engine with no other changes and put it into a truck application, one wouldn't get a 540/540 rating. It would be lower due to the cooling (if not other powertrain) limitations.

Example - back when the Cummins 5.9L 12 valve diesel was rated at 215 BHP for truck applications, the marine engine was rated at 370 BHP. Mercury rates the 24 valve Cummins ISB (QSB in marine service) at 425 BHP.

Rusty

[DriVer]

Originally Posted by RustyJC

Apples and oranges. What I'm saying is that, if you take the marine engine with no other changes and put it into a truck application, one wouldn't get a 540/540 rating. It would be lower due to the cooling (if not other powertrain) limitations.

Rusty is right. You'd have to go with an Allison MH3000 to handle the torque and I don't expect that would sit well with people if they had a gas motorhome and had to buy one of those.

Keep the torque someplace like 450 to 500 and I believe that an MH1K/2K could handle it.

[motohomer]

Here is (was) the 2010 marine 8.1 spec sheet:
http://www.gm.com/experience/technol..._HP_Marine.pdf
Intake looks different
Headers could be anything (no cats)
And a different ECM.
All add up to better specs, but not drasticly.

For comparison here is the "industrial - gas" 8.1:
http://www.gm.com/experience/technol...Industrial.pdf

[RustyJC]

Industrial = 255 BHP rating @ 2800 RPM; 511 lb-ft @ 1800 RPM

Marine = 419 BHP rating @ 5000 RPM; 503 lb-ft @ 4000 RPM

The RPM limitation of the industrial rating kills the BHP comparison between the two.

Rusty

[TXiceman]

After reading all of this, my mind is still set to the opinion that real trucks don't have spark plugs. From a performance and efficiency view point, I'd rather have a diesle power truck and car over small displacement blown gasser.

Ken

[DriVer]

Originally Posted by TXiceman

I'd rather have a diesel power truck and car over small displacement blown gasser.

Ken, I would not disagree with you 1 bit. Diesel engines are definitely gaining in popularity and affordability!