ECOTEC vs SBC vs O-540, A Power to Weight Ratio Discussion

[DynaMarine]

With the recent increase in discussion on the Ecotecs and where they might fit into the airboat industry I wanted to really dive into this and see what it's all about from a numbers perspective. Those that know me, know that I'm the type to analyize the hell out of something in order to either validate, improve on, or scrap a particular design or setup. So I figured I'd dig into this Ecotec thing and see what we could come up with.

My approach to it all was from a purely mathmatical perspective, kind of like a Car & Driver new car comparrision. Just how might these motor packages perform against the industry standards? Lets dig in.

First off lets establish some constants. I tried to keep it as apples to apples as I could, with the exception being the HP rating of the O-540. All the other motors used would be rated at 400hp.

#1 LS 5.3 or SBC 350ci Iron Block Motor
Weight - 525#
Horsepower - 400

#2 LS1/6 All Aluminum Motor
Weight - 450#
Horsepower - 400

#3 O-540 Aircraft Motor
Weight - 475#
Horsepower - 300

#4 2.4L Ecotec
Weight - 280#
Horsepower - 400

Gearbox on Carmotor Setup - 70#
Gearbox on Ecotec Setup - 60#

Prop on Carmotor Setup - #30
Prop on Ecotec and O-540 Setup - 25#

Now that we have that, I want picked an "average" weight for a typical ride boat that you might find any of these combos on. I picked a ride weight of 1800lbs as the base for an Iron Block CM setup and deducted the difference in the motor setups to get each configurations "standard" weight.

Lets look at the details of each setup and see if we can all agree on some level. Lets say a 3-4 person 14' Open boat with .190 bottom and poly with stainless rigging.

#1 (SBC/LS Iron Block Motor Ride Boat)
Motor - 525#
Gearbox - 70#
Prop - 30#
Rest of Boat - 1175#
Total - 1800#

#2 (LS1/6 Aluminum Motor Ride Boat)
Motor - 450#
Gearbox - 70#
Prop - 30#
Rest of Boat - 1175#
Total - 1725#

#3 (O-540 Motor Ride Boat)
Motor - 475#
Prop - 25#
Rest of Boat - 1175#
Total - 1675#

#4 (Ecotec Aluminum Motor Ride Boat)
Motor - 280#
Gearbox - 60#
Prop - 25#
Rest of Boat - 1175#
Total - 1540#

OK, now lets do the power to weight ratio for each.

#1 (Iron Motor) 1800# / 400hp = 4.5lb per HP

#2 (Aluminum LS) 1725# / 400hp = 4.31lb per HP

#3 (O-540 AC) 1675# / 300hp = 5.58lb per HP

#4 (2.4L Ecotec) 1540# / 400hp = 3.85lb per HP

We still agree on the numbers so far? Ok, now what does this actually mean? Maybe a better way to look at this would be how much increase in performance would one might expect to see. Better yet, what does the reduced weight equate to in actual performance? Lets figure out what the horsepower equivalent would look like. Basically, if I went from an an Iron Motor to an all aluminum LS, would the performance gain be significant enough? What about going from a O-540 to an Ecotec or even crazier...an LS to an Ecotec?!?!?!?

To figure the horsepower equivilant, we'll use a Horsepower to Weight Loss Formula that will tell us what additional HP we would need to achieve the same power to weight ratio, in essence resulting in the same performance. Formula looks like this...

Old Weight / New Power to Weight Ratio = HP Needed

Lets just look at the comparing an Ecotec to the others

#1 (Iron Motor) 1800# / 3.85 = 467.5HP

#2 (Aluminum LS) 1725# / 3.85 = 448HP

#3 (O-540 AC) 1675# / 3.85 = 435HP

#4 (2.4L Ecotec) 1540# / 3.85 = 400HP

What this essentially projects is that given the same theoretical boat, what HP would be needed to make it perform as good as the Ecotec numbers. Granted these are numbers and I'm not suggestion that it would outperform anything. Could be better, could be worse...still a lot of variables out there. So what does this mean. It suggests that an Iron motor setup would need to make 467.5hp, the LS would need 448hp and the O-540 would need to make 435hp in order to have the same power to weight ratio.

Now will it actually perform like that out in the marsh or wherever you ride...good question! There aren't enough of these things running around to really get some conclusive data. How many folks have actually switched from an SBC iron motor, LS or O-540 to an Ecotec and measured the difference? The folks that have made the switch all seem to rave about it, so there has to be SOME truth to the numbers right?

Me being a numbers guy, you might be able to see where I drew my conclusion that these little motors, if proven durable, will absolutely have a place in the airboat industry. At least convinced me enough to build a couple and see how they stack up against a 450HP LS1/6 boat.

Wonder how much this post will

[ptr34]

Ger my ride boat done. And we will have all the data needed .

[Waterthunder]

If I owned a LS that only made 400HP , I would Immediately start look for the missing plug wire!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[DynaMarine]

What's a bone stock 5.3L motor make, how about stock LS1?

Just to humor you Dave let's look at one of your budget Iron block motors or even a 475hp Aluminum LS.

(Iron LS) 1800# / 475hp = 3.78lb per HP

(Aluminum LS) 1725# / 475hp = 3.63lb per HP

(2.4L Ecotec) 1540# / 430hp = 3.58lb per HP

That's a hell of a lot closer for sure and I doubt the person driving would feel the difference in .2lbs per HP difference in the 2 boats. Might be different at the pump, but I've got no fuel data that I can claim on that.

[Tony480]

Exactly who the hell builds an LS that only makes 400 horse. Hell a bone stock LS3 from gm makes 430. And will make 500 easily with the right cam choice.

[DynaMarine]

Here you go Tony...just for you.

(Iron LS) 1800# / 500hp = 3.6lb per HP, same as an Ecotec

(Aluminum LS) 1725# / 500hp = 3.45lb per HP...beat out that Ecotec there

And just to clarify, I wasn't suggesting that the Ecotec is a replacement option for the LS, just comparing #'s is all. We all know every LS makes at least 500hp

[Tony480]

And the guys that are going to buy a 540 like them for their simplicity. An eco tech is far from that. Hell an injected 540 could be ran with no battery what so ever if need be. And as far as comparing it to a 5.3...most guys that are going to put a 5.3 on a boat are on a tight budget and get their motor from the junk yard and no 5.3 makes 400 and neither does any junk yard eco tech. The only thing you can compare it to is a 540. And even then you will have very few that will ever pay $14.5 for some 4 cylinder car motor that sounds like a Kubota diesel. Don't get me wrong those eco tec have their place and it's usually as a starter for a real motor

[Seven3]

Good thread. I absolutely agree these engines will have their place in the airboat industry. But IMO they're priced too close to the LS's to make a lot of people choose them over an LS. I'm not even an LS guy. Just saying that if I was building a CM boat I'd rather spend a few more $ and opt for the LS that is proven reliable and have excellent resale values. The LS has been called the greatest engine design of the last 20 years by Jalopnik (not the best media source, I know). People are shoving the LS in everything from Fords, Dodges, and even experimental aircraft I believe. And this is coming from an AC guy!

[eskimoboy]

Cheaper to operate (fuel consumption), cheaper to maintain (cheaper parts) and more than enough HP for guys that don't need to race. For guys like us that want to get into airboating that's a whole lot of incentive at a decent price.

[digginfool]

Somewhere along the way, you have to consider how much torque and where it's at.

[lyc180racer]

Another eco tech infomercial I think I'm going to puke.

[DynaMarine]

Your right Tony, no junkyard 5.3L makes 400hp and neither does a junkyard Ecotec. But like you said earlier, it doesn't take much to get 400+hp out of an LS and same goes for the Ecotec. What's Russ getting out of his Ecotec...400hp? I know JB550 motor is capable of 400+ and I'm sure Chuck and the otehr players will vouche for 400+ farily easily out of an Ecotec.

I know several folks who've pulled 5.3L salvage motors up here and put decent cam, couple swapped to higher compression pistons or milled the heads to bump up to 10:1 or 10.5:1 which they were looking for around 400hp. None of them dyno'd their motors, but there's enough build data online to see that the mods they did should've got them close to their target of 385-415hp.

Theirs an ass for every seat and a motor for every budget. I'm just hoping the Ecotec I've got sitting in the shop has enough umph to be a starter motor for your beast

[fl cracker]

Turbo Ecotec w/ cooling system , Gear Box,Prop & computer , is considerbly more expensive than a rebuilt 540. Untill a DD Ecotec can perform with a 540 it should even be considered in the same class. What does a fully dressed Eco w/ coolant , gearbox & prop weigh? The weight shown for the 540, is that SV or A/V?

[getchasumairboats]

How many of these 350-400 hp eco tecs have ya'll put together that are running ? How many hours do you have on them ?

[DynaMarine]

Fl Cracker...what's a rebuilt 300hp O-540 cost with oil cooler and all that jazz from Schmidt, Juringan any of the other reputable engine builders? I mean complete with starter kit, headers, oil cooler and all. $10,500 - 11,000ish maybe?

Fully dressed Ecotec with gearbox and prop should be around 475lbs, best estimate. I've got a 430hp Ecotec and I'll throw a GB and Prop on it and weigh it and see what we got. Add 20-25lbs for radiator and coolant and should come in around 500lbs.

[DynaMarine]

How many of these 350-400 hp eco tecs have ya'll put together that are running ? How many hours do you have on them ?

I'm putting one together now man, and we'll see how it holds up with Terry in the seat. I've got no clue how it'll hold up long-term, but we'll see. Everything we've seen so far says it will, but we all know an airboat is a little harder on stuff than other applications.

[DynaMarine]

Somewhere along the way, you have to consider how much torque and where it's at.

Very true....and we'll see soon enough I suppose.

[Tony480]

How many of these 350-400 hp eco tecs have ya'll put together that are running ? How many hours do you have on them ?

I'm putting one together now man, and we'll see how it holds up with Terry in the seat. I've got no clue how it'll hold up long-term, but we'll see. Everything we've seen so far says it will, but we all know an airboat is a little harder on stuff than other applications.

So the answer is none. And your trying to hype these things up and sell em without even knowing first hand if they will hold up

[getchasumairboats]

So ya'll are selling a product for $14,500 and you don't know if it's gonna last ????? And if it doesn't work then they are stuck with a gearbox that only fits a 4 cylinder and a prop that's to small for a V-8. Good luck with that. In a budget build from the salvage yard yep I could see it maybe. Imo

[DynaMarine]

So the answer is none. And your trying to hype these things up and sell em without even knowing first hand if they will hold up

Not trying to hype them up at all, this thread was just a technical discussion about power to weight. People can draw their own conclusions and a lot of folks read these forums just for info gathering purposes. Will I sell them and stand behind them, yep. I'm willing to take that "gamble" given the info I've seen on them.

Would I recommend it in place of an LS, nope. I love me some LS engines. But for someone that is looking to run a smaller boat, better fuel consumption and so on, yeah I'd likely throw an Ecotec out there as an option.

There's a growing number of them being used in commercial applications in Alaska and Louisiana...must be durable.

[JB550]

Let's see your 540 turn this prop.

[Tony480]

It will with a gear box...will yours turn it without it?

[JB550]

It will with a gear box...will yours turn it without it?

Will yours?

[plumcrazy]

the ecotecs i have driven will hang with the 540 even a geared one we did a compareson test 2 years ago thrust, speed, ground running, hill climbing ,after running identical routes the brand new 540 with a 1.5 stinger burned 3 times more av fuel at 5.25 per gal as apposed to 3.25 high test in the eco... the eco out performed it in every respect the man that owned the newly built 540 boat which by the way was 150 lbs lighter than the eco now drives a eco boat sold his 540 that week.... all i can say is if you get the oportunity to operate one do it it will make you smile then shake your head i have a customer in alaska who does 500 mile round trips all his buddys pay for fuel to be flown in to make the same trip he does with fuel on board its here its gonna stay

[lyc180racer]

Tony if you buy now we will throw in a 2nd Eco tech motor for free you only need to pay shipping and handling