ILMORdude

Everyone is always happy with the gun results in LOTO.

Uncle Dave

Pretty sure you mean this 408. Right? Same build from the article you quote.

Notice the headers- dry and super large with a nice long collector.

Not a wet marine header.

Notice the accessories - or lack thereof.

No seapump
No recirculating pump
No alternator
No power steering
No Ignition (ignition is supplied by the dyno and powered externally - usually)

Im actually a bit surprised it didnt really make any more torque than my 406 small block.

It also has an endless supply of fairly cool water.
It was dyno'd using 93 Octane gas (you cannot find that in any marina)

By the time you add all of these things together the effect it would have on that 408 would be dazzling, and I doubt it would put out near what the Ilmor does with all of the above hooked up and running. Then it has to idle in and out of gear, and not revert water...

and then theres the warranty..........

Uncle Dave

Raylar

I know I am gonna take some real flack over this post, but here it goes!
It seems as though we always seem to have this automotive magazine and automotive high performance representations and comparisons on how much horsepower and torque LS engines can and do make? Lets face it in high performance automotive use and even race car usage LS engines in various sizes, build types and configurations can make anywhere between 350HP and 2000hp. This has been done demonstrated and verified probably over a 1000 times in the US alone in the last 4-5 years alone. No one hear is arguing or saying that the LS based engines are not great engines, no one is saying they can't make awesome horsepower, no one is saying that they are not a good PLATFORM for marine usage and I am not saying they will make 20% less power because of wet exhaust usage!
What I and others here on OSO are saying who have good marine engine knowledge and some good LS engine development experience is that when you take an LS or LSX based engine even with the best reworked GM or aftermarket heads, put in camshafts (that will work in wet exhausts in boats)and marine header systems, use cubic inch sizes of lets say 427 to 454 and set them up to idle at lets say 650-750 rpms (for drive life) without any reversion, keep them in an rpm limit of lets say 6200rpms, ask them to make high torque from lets say 2500 rpms to 5500rpms, install and run all the accessories needed such as raw water pump, circulating water pump, power steering pump, alternator and complete serpentine belt drive system with tensioner, use a complete freshwater (heat exchanger) cooling system to protect all aluminum parts (heads especially), use heavy flywheel and coupler, build them to run under high loads for many hundreds of hours in boats, warranty them for a minimum of one year maybe more and have them meet current EPA, Carb and European emmissions standards with catalyst exhaust control systems -YOUR HORSEPOWER DEVELOPMENT WILL BE ABOUT BETWEEN 500 AND 600hp AT BEST! These puppies complete will cost the boat buyer about $25-$35K depending on whose offering we are talking about. You ain't gonna buy one of these LS or LSX high performance full marine engines for $10-20$K that will do all these things.

I guess what I am saying here is I am just about sick and tired of the constant comparison of performance automotive use and performance of LS & LSX based engines with real working marine LS & LSX engines-THEY AIN'T THE SAME ! and this type of constant comparison will only misguide and misinform potential marine engine interested and serious buyers or users who are not well versed or familiar with LS & LSX marine engine offerings and what it takes to get these engines in marine high performance endurance trim.

This thread was started to discuss the new Ilmor MV570 LSX marine engine, which is just such an engine and produces results right inline with my statements above. Ilmor has done a magnificent job of bringing a complete, well engineered and constructed LSX marine engine to market that I am sure will perform beautifully in correct marine applications and will give years of trouble free performance and reliability just as their V-10 marine engines have done. Ilmor does not put their name on mediocere marine engine offerings!

For any others out there who can deliver such a product or viable offering then I say BRING IT ON! it will be well received and if you can exceed these ranges for reliable power and torque it will be even more well received.

Jim has built some nice LS marine engines and if they can be put into production and deliver on these requirements then great, he should get busy and put them to market! He as well as anyone should also be prepared to prove up their performance and reliability.

I know there are nearly no marine performance magazines now for readers but lets stop this automotive performance substitution and comparisons especially from magazine sources- it's really is getting old and it reads like BAD BENCH RACING where people are comparing apples to tomatoes! they are both fruit, but that's where the comparison stops!

As for this developing fray between JimKid and Skater 30 it seems like the only real finality other than their inflamatory tossing tennis match thats going on may be some sort of special SHOOTOUT that might be arrainged in Michigan this year that should be convienent to both parties. What's that other old saying "When the green light drops, the bull**** stops" Should get a big attendance from OSO'ers and interested performance boaters AND BE THE TOPIC FOR A LOT OF FUTURE DISCUSSIONS!

Best Regards,
Ray @ Raylar

fastestbowtie

That might be the 408, but I do not believe that is the current test. They did use a motor that had been used for other test previously to test some new aftermarket cathedral and square port heads. They did use 1 7/8 long tube American Racing headers and yes I am sure it was dyno'd without accesories. But it was also dyno'd with off the shelf Fast intakes, stock LS3 rockers and other off the shelf parts... I realize that the lack of accesories would affect the final numbers (though we do not know for sure if the Ilmor was dyno'd with all accesories either) and as mentioned the exhaust would have an affect, but how much? As anyone actually dyno'd a motor back to back with off the shelf automotive headers and then again with a high dollar set of marine headers (the tubes on those CMI's don't look too small either). They also turned that 408 upwards of 6600 RPMS though the peak numbers were reached around 6300-6400 and all 4 test were north of 600 HP by 5500 or so. In any case I would expect the extra 45 inches to more than make up any of that difference. Like I said perhaps they were just going for a docile relatively high powered large inch small block for which they definitely achieved their goals. It is just as a LS enthusiast the results leave a little to be desired for me. UD, I forget how big your small block is, but lets just say you had the resources Ilmor has when you were building it. If you paired your combo with a set of canted valve 14 deg heads and tubular exhaust and a custom intake with custom EFI, would you not expect it to make more than 570 HP? Like I said, it may be the perfect small block with big block performance and it might make a perfect OEM installation to compete with Mercruisers 525 or 565, I would have just expected a little more.

Uncle Dave

Fair questions. I believe based on its history Ilmor could make an engine from scratch do do whatever they wished with one exception. Hit a price point.

When I spoke with one of Californias most highly regarded engine builders about accessories and header loss on his marine engines compared to a raw dyno the number floated out was around 100 on a 500 HP engine. This guy has an in house dyno and more than enough data to back his claim, and is one of the few builders that can deal with my Mercury product and my Ilmor product. (that'll narrow it down greatly)

When I said the difference all that stuff makes is dazzling I wasnt being overly dramatic.

Ray is right on the money - you cant compare a block bolted to a stand with one ready to run for the marine application.
This is why there arent 10 guys doing it right now.

If we reverse this the comparison and say the Ilmor under the same conditions puts out about 670 HP (and has a warranty and actually idles AND passes CARB) would you feel better about Ilmors LSX representation to the enthusiast?

Uncle Dave

fastestbowtie

I know Ray gets passionate about these discussions and he has most likely forgotten more about marine engines than most of us will ever know so I respect his opinions but I still think that Ilmor has left a little on the table when it comes to their LS marine power plants. Who knows, maybe that is all in their plan. Start out conservative and then tweak and improve as they gain experience. Is that not how they started with their V-10 program. Remember it started out at 550 HP, then they made modifications and improvements and before you know it they are up to 700+ HP. I am also not so quick to disregard automotive technology. Granted I have nothing to compare to most of the HP mils on this forum, but my 355 ci small block was built by an automotive machine shop back in 1995 with all automotive spec off the shelf parts and made 425 HP and 450 ft/lbs of tq and now has almost 400 hours on it since the build and has never had a mechanical issue (now the factory 1987 EFI system and electronics are another story).

HaxbySpeed

Many times.. It's about 25-30hp on a 600 hp engine.

fastestbowtie

ABSOLUTELY... If that is an accurate number it would explain everything. That was why I questioned if it made a 20% difference (which is exactly what a 100 hp would be on a 500 hp motor), but even Ray said it would not make that much difference. Was he comparing car headers to wet high perf marine headers or stock Merc style manifolds?

HaxbySpeed

On a production engine there will always be something left on the table or compromises made. They delivered an engine that will run on junk gas and have a very long service life. I don't doubt that they could release a 700hp version that runs on premium fuel and has a 200 hr service life, I just don't think that's what they were after. They built a spin off of an engine they were already using in ski boats.
On 91 octane a GM LSX 454 with a cam swap made 628hp and 604ft/lbs running wet aluminum manifolds and all accessories. Sure Ilmor's engine could make more power but that can be said of anything. I can give you an extra 40+hp on almost any LS powered vehicle by hitting a few buttons on my Keyboard with HP Tuners. Did GM let you down? No, they built it conservatively, just like Ilmor.

Uncle Dave

Ray didnt say 20% because of exhaust alone.

Its all the stuff on top of the exhaust he and I both came up witha similar list of "stuff".

Every driven device carries a HP penalty.

Ray could probably tell you off the top off his head about what each driven accessory "cost" The recirculation pump itself is about 14 HP. The alternator varies based on load- but its pretty safe to assume a boat is in charge mode quite a bit.


The exhaust isnt cut and dried either.

Oh....the marine exhaust may dyno only say 30 HP down- but that isnt in the boat yet.

If the pipes go straight out it will probably put out the same power on the dyno - but if your installation requires you to put and "s" bend into it- look at losing 10-20 more.

All that stuffs add up really quickly.

UD