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View Full Version : Engine Rebuild, TBW, ZO


jwroblew
07-07-2009, 10:35 AM
I've asked the question before but here goes again.

I've got an '03 X7 with 1400 hours, by the end of the season most likely 1600. It has the RTP TBI engine in it with 310 HP. The boat is getting a little tired so I figure an engine rebuild is due in a year or two.

I also ski a lot, and would like to go to Zero Off, love the simplicity of the system and tournaments are pulled with it so why not.

Selling my boat and buying a new to me one in this economic climate doesn't make sense. With that many hours I'm probably looking at low $20s, if I can sell it, and a 2007 or newer is going to run $40.

So what do I need:
Do I need to go to the RTP-1 set up? MPFE instead of TBI?
Intake
Throttle body
Fuel Rail
Throttle by wire module
Zero Off with new ECU
MMDC?
New wiring?

I'm hoping I can due it for around $5K, $2k of it being the Zero Off and new ecu. I would be doing all the work my self.

JimN
07-07-2009, 10:55 AM
I've asked the question before but here goes again.

I've got an '03 X7 with 1400 hours, by the end of the season most likely 1600. It has the RTP TBI engine in it with 310 HP. The boat is getting a little tired so I figure an engine rebuild is due in a year or two.

I also ski a lot, and would like to go to Zero Off, love the simplicity of the system and tournaments are pulled with it so why not.

Selling my boat and buying a new to me one in this economic climate doesn't make sense. With that many hours I'm probably looking at low $20s, if I can sell it, and a 2007 or newer is going to run $40.

So what do I need:
Do I need to go to the RTP-1 set up? MPFE instead of TBI?
Intake
Throttle body
Fuel Rail
Throttle by wire module
Zero Off with new ECU
MMDC?
New wiring?

I'm hoping I can due it for around $5K, $2k of it being the Zero Off and new ecu. I would be doing all the work my self.

Before you rebuild anything, do some testing to rule out what's making it "tired". Compression, vacuum and cylinder leakdown, spark intensity, fuel pressure/volume and engine/shaft alignment can all make it slower but the alignment can knock off a couple of MPH and be fixed without needing more than new strut bushings and some tweaking. The first three will indicate the general health of the motor and don't take long to test.

If you do all of the things you listed, you'd be better off getting a different boat, IMO.

jwroblew
07-07-2009, 11:32 AM
I would love a new boat but a $20K vs $5k is big to me..

JimN
07-07-2009, 06:25 PM
I would love a new boat but a $20K vs $5k is big to me..

My main point was to find out why it's acting kind of puny and that may take care of the whole thing without having to spend even $5K. The harness alone would be pretty extensive and if that's not done to spec, it can cause all kinds of grief. FYI- the intake manifold on the Indmar motors is about as good as it gets and if you were to get a MFI setup instead of TBI, you would probably be able to just recal the ECM since you have a MEFI 5 controller. If you make it into an LTR, it would be the easiest route.

Or, call MC and ask if they have a "bobtail" motor that you could drop in. As bad as things have been for them, they may be glad just to move a spare motor out the door.

André
07-07-2009, 06:59 PM
Does that 5k include the engine rebuilt that you think you need?
How much an 06 with MCX is selling for in your area?
I think you could easily be in a nice DBW boat with ZO and more HP then your RTP for WAY less then 40k...

jwroblew
07-07-2009, 07:05 PM
OK, tired might be a little bit of an exaggeration, it runs fine but I would like to go to ZO so why not do the rebuild at the same time. As far as recaling the ECM, wouldn't mater, I need to go to the e-controls ECM anyway. The ZO website only lists MC's going back to 2007, but I don't know if it would work on older boats, I know you need TBW, and when you go through the ordering process it does not ask what engine, so I don't know what they do about the ECM. If I could keep the TBI system and go to ZO I would, less work, I think. I think the RTP was MPFI making it the RTP-1 in 2007, if not earlier.

What is a LTR, I didn't see it on the Indmar web site?
What is a "bobtail" motor?

JimN
07-07-2009, 09:06 PM
OK, tired might be a little bit of an exaggeration, it runs fine but I would like to go to ZO so why not do the rebuild at the same time. As far as recaling the ECM, wouldn't mater, I need to go to the e-controls ECM anyway. The ZO website only lists MC's going back to 2007, but I don't know if it would work on older boats, I know you need TBW, and when you go through the ordering process it does not ask what engine, so I don't know what they do about the ECM. If I could keep the TBI system and go to ZO I would, less work, I think. I think the RTP was MPFI making it the RTP-1 in 2007, if not earlier.

What is a LTR, I didn't see it on the Indmar web site?
What is a "bobtail" motor?

LTR is the motor with the big metal shroud intake plenum. It's really not too much more torque than the TBI but its curve is smoother and it adds 20 HP. Nice motor and you should be able to retro-fit the TBW. If the E-controls ECM looks like the MEFI, it probably is.

There's not that much wrong with TBI really, but the ignition using a distributor, isn't as consistent as the Northstar or Coil Near Plug. TBI also has a nice bump in the torque curve at the bottom end, which is good for pulling stumps.

jwroblew
07-07-2009, 11:48 PM
here is a pic of the e-controls ecu
49084

what would I need for a retrofit for TBW / DBW?

JimN
07-08-2009, 12:08 AM
here is a pic of the e-controls ecu
49084

what would I need for a retrofit for TBW / DBW?

TBW requires a servo at the throttle and a way to control it at the helm. This also needs fail-safe measures, in case of mechanical failure or incapacitation of the driver. Usually, these are defaults that are set in the program.

That doesn't look like a Delphi controller, but it doesn't mean it isn't.

I forgot to reply to what a "bobtail" is- it's a complete motor with the entire wiring harness, ready to plug into the boat harness, connect to the transmission, linkage and fuel system.

jwroblew
07-08-2009, 11:22 AM
The ecu is an e-controls unit, it comes with ZO, it replaces the black delphi unit with the cooling fins.

I would have thought DBW would eliminate a servo at the engine, the throttle would talk to the fuel delivery sytem directly.

Who would I talk to about a "bobtail"? This sounds like an expensive way to go, but know I'm curious.

dummy
07-08-2009, 11:42 AM
I would have thought DBW would eliminate a servo at the engine, the throttle would talk to the fuel delivery sytem directly.


Yeah, but something still needs to open the throttle body blade(s).

shepherd
07-08-2009, 11:55 AM
Are you wanting to replace the engine just so you can run Zero Off? :confused:
I've skied with Zero Off and it ain't all that impressive.

JimN
07-08-2009, 12:59 PM
The ecu is an e-controls unit, it comes with ZO, it replaces the black delphi unit with the cooling fins.

I would have thought DBW would eliminate a servo at the engine, the throttle would talk to the fuel delivery sytem directly.

Who would I talk to about a "bobtail"? This sounds like an expensive way to go, but know I'm curious.

I saw the photo but I meant that Delphi could make the controller and E-controls may just put their name on it.

As far as DBW- the RPM increases because the throttle opens, not because more fuel was added. The servo controls throttle position and the MC version has three tracers at each end so that, if two go out, it could still work but if two do fail, it defaults to idle, to keep from putting the passengers in harm's way with excessive speed and no throttle response.

Talk to technical or parts at MC or if you have a dealer that you like, have them call. It's how they get the motors from Indmar IIRC, although they may install the engine harnesses in Vonore,

JohnE
07-08-2009, 01:17 PM
Are you wanting to replace the engine just so you can run Zero Off? :confused:
I've skied with Zero Off and it ain't all that impressive.

I've ski'd with Zero Off and I ain't all that impressive.;)

AussieMC
07-21-2009, 01:49 AM
Has anyone got any idea of the costs invovled in upgrading to a TBW setup.
Even if Zero off is not impressive, all the tournaments down under are being pulled with it next season and I wouldn't mind upgrading my boat so as I could train behind it.(costs permitting). Our club is in the process of ordering a new boat and upgrading, (but it's a Bu.:D)