Why Did Indmar Reinvent The Wheel?

[UNSTUCK]

My boat needs more power, BAD! Fortunately it has a GM L96 (LS based motor). The LS series of engines have become hugely popular for builders in the last 15 or so years for their awesome reliability and ease of modding. Indmar buys bone stock L96 motors from GM and basically just adds their appearance package and marine exhaust. Oh, and they had E-Controls build them an ecm with their own "proprietary" tune. At this point I can't find anyone who has the ability to tune these ecm's. Seems like my two options are to switch over to MEFI or maybe even just swap out the ecm to a GM ecm and modify the harness to plug into it. With either of these OS I can tune all I want. The GM system being easier for me because I can put my local tuner that I use often on car builds in the boat and tune on the fly. Maybe even at a discounted rate if I give him a pull or two afterwards.
I just wonder why Indmar would go through all the expense and heartache just to use their own system when others are already out there that work as good or even better than what they have? What am I missing?

[TeamAllen]

I would be surprised if these guys can't help you.
https://www.obd2allinone.com/mefiecms.asp

[duffymahoney]

My boat needs more power, BAD! Fortunately it has a GM L96 (LS based motor). The LS series of engines have become hugely popular for builders in the last 15 or so years for their awesome reliability and ease of modding. Indmar buys bone stock L96 motors from GM and basically just adds their appearance package and marine exhaust. Oh, and they had E-Controls build them an ecm with their own "proprietary" tune. At this point I can't find anyone who has the ability to tune these ecm's. Seems like my two options are to switch over to MEFI or maybe even just swap out the ecm to a GM ecm and modify the harness to plug into it. With either of these OS I can tune all I want. The GM system being easier for me because I can put my local tuner that I use often on car builds in the boat and tune on the fly. Maybe even at a discounted rate if I give him a pull or two afterwards.
I just wonder why Indmar would go through all the expense and heartache just to use their own system when others are already out there that work as good or even better than what they have? What am I missing?

What exactly are you looking for? For top end? Surfing? Most of this can be fully fixed with a new prop.

[ericinmich]

One reason is to better control how their engines are run. Some will tune an engine and damage it, then try to get warranty to pay. It's basically stealing but some folks think it's fine...

[UNSTUCK]

It may be that I haven't found the right prop. I'm on my 3rd one in a months time and still am not there. So far the best prop (2937) to pull my weight has me running at over 4500 rpms at 11.5 mph with a top speed of around 24, empty. I'm not comfortable with that sustained rpm. The next prop (2419, I think), is my current one and won't get to speed fully loaded. I have to dump almost half my ballast if the water is less than glass. It's very similar to my old 1235 which wouldn't do it either. A cup change may get me to speed, but only save a few hundred RPM. I'd really like to be surfing under 4k rpm. I think if I had more power from a simple cam swap I could prop up and pull hard and still have a nice cruise speed. Plus, who doesn't want more HP? And it is still pretty cheap to do. Depending on how the ecm tune plays out it could be done real cheap. WAY less than the upgrade from a new 400 to 440, and I could get 100 hp out of it.

In the auto world, ecm are tunable from day one. I'm sure it voids warranties, and could lead to stealing, which I agree is wrong. I'm not sure what they do about that. My boat is out of warranty and I understand what can happen with a poor tune job.

Mike, I have been talking with Bob over there. He said if it is in fact an E-controls ecm, he is pretty sure no one tunes them. I will look closely at the ecm this weekend.

[Thegerman618]

How much weight are you running and where is it placed? I have a hard believing the motor is your problem. I ran 4000+lbs on an old GM 5.7L 340HP with a moderate surf prop (1235) and a surf a system to boot and the motor didn't have any problems.

[hcooperrn]

I think you're wanting more torque, not hp, right? My Raptor 400 has 400lb/ft, and it's moving my Z3 with Surf XL plus 500lbs, plus a full crew, at 5500', with only a hint of cavitation and no problems getting to speed -- are you heavier than that?

I've done GM tuning on tuned-port camaros and corvettes before, and I know that while I could usually squeeze out more hp at the top end pretty easily, getting more grunt out of the bottom end was tough without changing the cam and intake to start with. In other words, if your engine is optimally tuned, it takes more parts to get a bigger impact.

I do know that the Indmar 400 and 440 are the same parts, just different tunes. However, that's only a 10% increase in torque to get you up on plane. By the time you factor in drive train loss and prop inefficiency, the tune itself isn't too dramatic a difference, at least on paper.

Just my opinion -- from your description, the engine sounds weak in general, not just from the tune. I'd be doing a full tune-up, checking base timing to make sure nothing has slipped, checking compression, etc. Sometimes engines just don't have the grunt they should, and just the process of a re-ring can bring it back to life?

I could be way off -- I'm still leaning on my car experience while getting deeper into boats.

[duffymahoney]

It may be that I haven't found the right prop. I'm on my 3rd one in a months time and still am not there. So far the best prop (2937) to pull my weight has me running at over 4500 rpms at 11.5 mph with a top speed of around 24, empty. I'm not comfortable with that sustained rpm. The next prop (2419, I think), is my current one and won't get to speed fully loaded. I have to dump almost half my ballast if the water is less than glass. It's very similar to my old 1235 which wouldn't do it either. A cup change may get me to speed, but only save a few hundred RPM. I'd really like to be surfing under 4k rpm. I think if I had more power from a simple cam swap I could prop up and pull hard and still have a nice cruise speed. Plus, who doesn't want more HP? And it is still pretty cheap to do. Depending on how the ecm tune plays out it could be done real cheap. WAY less than the upgrade from a new 400 to 440, and I could get 100 hp out of it.

In the auto world, ecm are tunable from day one. I'm sure it voids warranties, and could lead to stealing, which I agree is wrong. I'm not sure what they do about that. My boat is out of warranty and I understand what can happen with a poor tune job.

Mike, I have been talking with Bob over there. He said if it is in fact an E-controls ecm, he is pretty sure no one tunes them. I will look closely at the ecm this weekend.

I doubt you will be able to tune the motor enough to notice a difference. I bet you have just the wrong props.

What v-drive do you have? Blue or black? I am guessing you have the 1:1 which means you would probably need a 3 blade prop like the 911.

[Germaine Marine]

1. V drive Ratio
2. distance available from top of blade to Hull

Those two things are needed to get you the right prop.

I am 100% confident that you just have been getting the wrong prop...

No one at the MB forum with your model can help you get going? Thats most unfortunate if true.......

[Bakes5]

How much weight are you running in that thing? What speed are you trying to get up to with the 2419? I mean, if your over revving with the 11 pitch and the 12 pitch isn't cutting it, that does not make sense. Heavy weight and full crew with the 2419?

24 mph sounds about right with an 11 pitch prop and 1.5 transmission.

I don't think any tune is going to help you get a 24 foot boat with 5000lbs ballast onto plane.

[UNSTUCK]

Acme said I should have a 1.7 ratio. I looked at the tag on the drive and it says 1.4. Fully loaded I'm at 2400 in hard tanks, from the rear up to about the driver seat. I then have 2- 1100 bags in the rear, I run a 750 in the bow. That is normally with my wife and 3 young kids, so pretty minimal people weight. If I fill the boat with people like last weekend I run without the bow bag so people will fit up front, I then had to almost empty the hard tanks. That was with 13 total people. Mostly adults. All this testing is done at a lake at about 4500'.

My thought is I will change the cam and then tune to make the engine work better with that cam. The 400 and 440 are VERY similar engines until the top of the RPM range. On paper, most people wouldn't notice a difference between the two engines. It may be true that the engine is not running perfect. I just rolled 200 hours which I would think should still be good for a while before a tune up. I also have a hard time thinking boats, with my car knowledge. In the end, the engine has no idea what it's spinning though. It could be a transmission or genset. It doesn't care. It just feels load.

Duffy, like I said before, I'm not looking just to tune. I need to tune to compensate for the mechanical changes.

Jason, I remember thinking I should have room for a 15.5" prop, at least to the hull. I don't remember really looking at trailer clearance though. I haven't given up on props, but not sure where to go without accepting running the engine at that high rpm all day long. Do you really think I could find a prop that would get me 11.5 mph and stay under 4k rpm's? In my mind, having more HP would allow me to put the 1235 or similar back on and have the pull and rpm's I want. As for the MB forum.... Well I posted up here, not there, for a reason.

Bakes I will double check my prop now. I know it's a 15x12, but don't remember which cup. I agree no tune alone will help, but a cam should.

[chpthril]

These hulls arent really planing hulls as compared to that of a bow rider or go fast. Have you considered that you have too much aft ballast and no amount pf prop/HP/torque is going to puch the boat through the water at a speed that well below planing.

[Germaine Marine]

Acme said I should have a 1.7 ratio. I looked at the tag on the drive and it says 1.4. Fully loaded I'm at 2400 in hard tanks, from the rear up to about the driver seat. I then have 2- 1100 bags in the rear, I run a 750 in the bow. That is normally with my wife and 3 young kids, so pretty minimal people weight. If I fill the boat with people like last weekend I run without the bow bag so people will fit up front, I then had to almost empty the hard tanks. That was with 13 total people. Mostly adults. All this testing is done at a lake at about 4500'.

My thought is I will change the cam and then tune to make the engine work better with that cam. The 400 and 440 are VERY similar engines until the top of the RPM range. On paper, most people wouldn't notice a difference between the two engines. It may be true that the engine is not running perfect. I just rolled 200 hours which I would think should still be good for a while before a tune up. I also have a hard time thinking boats, with my car knowledge. In the end, the engine has no idea what it's spinning though. It could be a transmission or genset. It doesn't care. It just feels load.

Duffy, like I said before, I'm not looking just to tune. I need to tune to compensate for the mechanical changes.

Jason, I remember thinking I should have room for a 15.5" prop, at least to the hull. I don't remember really looking at trailer clearance though. I haven't given up on props, but not sure where to go without accepting running the engine at that high rpm all day long. Do you really think I could find a prop that would get me 11.5 mph and stay under 4k rpm's? In my mind, having more HP would allow me to put the 1235 or similar back on and have the pull and rpm's I want. As for the MB forum.... Well I posted up here, not there, for a reason.

Bakes I will double check my prop now. I know it's a 15x12, but don't remember which cup. I agree no tune alone will help, but a cam should.

/1/

i absolutely do. But it really is imperative to know exactly what Ratio that boat is before I can tell you where I would go.

For example.. Tige went to a 2-1 at the end of last year, and by all accounts its the right move... "IF" you have enough hull clearance to run a big wheel, its why Tige changed the strut and went to a 1-1/4....... The 2-1 has no advantage unless you can run atleast a 17 inch wheel preferably 18-20. Without the necessary room, the play would have been to go to a 1.76 with roughly a 16-16.5 and it would be money.

The nice thing, the new rzx 2 and 3 look to be able to run a 17.... its close but we are right at about 3/4 inch mark with a 17 on it....

Sorry to go off topic.

Squeeze everything you can out of what you have and dial the pitch accordingly.. Diameter Diameter Diameter when it comes to surfing.... As much as your motor will turn.

I would feel comfortable with 3/4 clearance if it were me, I know buddies who are at 5/8 with out issue.

[Germaine Marine]

As for Indmar.. the dyno stuff I have seen between the 400-440-460 is all pretty comparable on the torque side up to 3500rpm, its after that we start to see separation.

If I remember correctly, the dyno numbers on the 400 440 and 575 were ...

Hp Tq

350 404
400 430
530 575

Dont remember the 460 info... I actually dont think I ever saw info for that option.

[chpthril]

I agree that if there is ANY question about what the v-drive ratio is, you absolutely have to confirm this, or everything else is just tossing darts with a blindfold. On paper, a larger prop will reduce the engine rpm, but the trade off is, it takes more engine to turn that larger wheel. The answer for that is, another drop in pitch, which you guessed it, RPM go back up.