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Head Janitor
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Discussion Starter · #1 ·
Ok, Here's a quick question. Right now I have water injected through transom headers and I'm wanting to add EFI to my boat. I'd also like to utilize factory type and wideband O2 sensors...

Can I do that with water JACKETED through transom headers...or do they still run too cool and still have too much moisture?

Are dry over-the-transom headers the only option?



Also - how would one accurately install EGT sensors?
 

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It can be done with jacketed through transom headers but to be safe I would make them fully jacketed all the way to the tip and make sure the tips are above the waterline
 

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Discussion Starter · #3 ·
It can be done with jacketed through transom headers but to be safe I would make them fully jacketed all the way to the tip and make sure the tips are above the waterline

That's sort of what I figured would be the answer; my exhaust is already just below the waterline...so I'm thinking the "safest" thing is to go over the transom...
 

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Resident Ford Nut
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That's sort of what I figured would be the answer; my exhaust is already just below the waterline...so I'm thinking the "safest" thing is to go over the transom...
Is this for a 1 time tuning experience or something you want to keep in the boat for a gizmo?

do you want to put an egt probe in each cly or just a lean one?

S CP
 

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I have probes mounted 8" after turbos and less than 2' from merge to water with double jacketed tubes going to thruhull outlets with Salisbury flaps, never had a problem with moisture on the sensors!
 

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I have probes mounted 8" after turbos and less than 2' from merge to water with double jacketed tubes going to thruhull outlets with Salisbury flaps, never had a problem with moisture on the sensors!
Right, but turbos pretty much kill any pulses from the exhaust. The pulses make it a much more dynamic environment.
 

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Discussion Starter · #7 ·
Is this for a 1 time tuning experience or something you want to keep in the boat for a gizmo?

do you want to put an egt probe in each cly or just a lean one?

S CP
Probably wouldn't do 8 EGT probes...but to be honest, I'm pretty new to the EGT thing...

I would like to keep the O2's on the boat all the time. If I'm only using it for initial tuning then I have it "all figured out".



I have probes mounted 8" after turbos and less than 2' from merge to water with double jacketed tubes going to thruhull outlets with Salisbury flaps, never had a problem with moisture on the sensors!
2 feet, or 2 inches? I don't think I have that much exhaust...

I would like to see your exhaust setup, though - I do eventually plan to go turbo...but not yet.


Right, but turbos pretty much kill any pulses from the exhaust. The pulses make it a much more dynamic environment.
I think I already have a marginally "safe" cam for water injected headers...
 

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I agree with thread #2. Even if your exhaust is below or slightly below water line. All that really happens is the O2s get fuzzed up and screw your tune and you will know about it. Im sure your 5 wires are heated, that helps. Eliminate the water for the mean time and make it fire up nice and quick (base map tuning). This will help keep the O2s clean if it just fires looking at the switch. Once its lit, with your small cam , the O2s will last. If you are planning on idleing around a lot., dont.
 

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21 Daytona
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What exhaust do you have now?
I added O2 bungs to my Imco's
They exit under water at idle
And blend 18" after the sensors
I have a wide band on one side and a narrow on the other
No problems so far
Let's see what you have


Sent from my iPhone
 

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Discussion Starter · #11 ·
Outlaw - below is some pics of my current exhaust setup. Do you run water jacketed, or dry, or what?





 

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I'm running a jacketed exhaust, I'm not sure what might be available for your engine, I'm guessing you want to reinstall the EFI??
 

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Discussion Starter · #13 ·
I'm running a jacketed exhaust, I'm not sure what might be available for your engine, I'm guessing you want to reinstall the EFI??

Yes - you are correct. Lightning says they make LS1 jacketed headers...but I haven't priced them yet.


Been seriously considering going to a twin turbo setup...in which case I'd still probably need to do over-the-transom exhaust...
 

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Highaboosta
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Formula ZR,

That looks like a mercruiser heat exchanger, how has that been working for you ?
It looks like that same size unit that's on the 4 cylinder 470 mercruiser engine in my son in laws boat.
 

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Discussion Starter · #15 ·
Formula ZR,

That looks like a mercruiser heat exchanger, how has that been working for you ?
It looks like that same size unit that's on the 4 cylinder 470 mercruiser engine in my son in laws boat.
The one I'm using is a Westerbeke 36903 - the one pictured was my old one that I painted black, but it *should* be red. Shortly after that picture I discovered it had some internal leaks (no doubt from several years of offshore duty before I got it, among other things). I believe the one I use is supposed to be for a diesel generator...but I'm not sure.

Anyway, for me it works great. My engine is all aluminum, so it's a little easier to cool anyway. The temp stays at a mostly rock solid 180*. The end caps come off, which makes cleaning the fresh water section very easy if you get trash in it. I probably need to go a to sea strainer anyway. I'd assume a bigger heat exchanger would be needed for big horsepower...but I don't know for sure.
 

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Highaboosta
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Interesting,

Did it take some experimentation to get the flow right from the jet pump ?
Do you use a thermostat ?
 

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Discussion Starter · #17 · (Edited)
Interesting,

Did it take some experimentation to get the flow right from the jet pump ?
Do you use a thermostat ?
Not really - the black heat exchanger was bought used for super cheap (and was used on my first LS1 jet boat)...and just happened to be one of the size that appears to be working with fittings in the right place. Basically what I'm saying is my heat exchanger selection was based on nothing except price/availability.

As for the flow, well...mine is set up kind of weird. I have a T on the inlet, with one side going to the heat exchanger and the other side going to the exhaust. I have a water pressure relief kit on it, and that actually "relieves" into the exhaust side of the water. So...the short version of the story is unrestricted water, but with a pressure relief.

I do run a thermostat - on the LS motors the housing is integrated into the water pump housing...that's actually what the lower hose attaches to. I would assume the thermostat is why I didn't have to "dial in" the flow from the jet pump.



I was lucky in that this was one of the FEW aspects of putting an LS1 into a boat (twice) that actually fell into place without much headache.
 
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