Who's swapped to an LT1

seeray

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May 4, 2012
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Ive seen lots of posts searching regarding this but who has done it?
Has anyone kept it fuel injected and if you did how did you wire the shift interrupt?
 

Bondo

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Re: Who's swapped to an LT1

Ive seen lots of posts searching regarding this but who has done it?
Has anyone kept it fuel injected and if you did how did you wire the shift interrupt?

Ayuh,.... Welcome Aboard,.... For various reasons, it won't work....
 

seeray

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Re: Who's swapped to an LT1

What are some of the issues? i don't see why it wont work. There is a carb intake manifold available for the LT1 and everything is swappable with the addition of an inline fuel pump, but i would like the fuel injection.

I was asking if anyone has done it before. Not opinions on if it will work or not.
 

Don S

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Re: Who's swapped to an LT1

The automotive EFI is not setup for running in water, and at cooler operating temps, no O2 sensors, doesn't play well with shift interruper switches, to name a few problems. Plus, none of it is marine rated for safety.
 

seeray

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Re: Who's swapped to an LT1

Im only asking if anyone has done it....Looking for some insight or ideas on how to make it work. Maybe somone to brainstorm with.

I have read plenty of mis-informed posts of why people think the "bottom end wont hold" or how "they are different engines".



Im looking on how to make it work. Am i looking in the wrong place?

I apreciate the regurgatation that it wont work though. (it will)


I am trying to decide between the delteq or the "northstar" ignition sysytem thats used on mastercrafts/aftermarket auto parts. Or using 24x EFI with an ls1 pcm, eliminating not only the optical drive that the mastercrafts used but upgrading to a better pcm and ignition system used on the new LQ4 and lsa marine engines.


No, oxygen sensors are not a problem and havent been for a while.(welcome to the 21s century) Running speed density is how many after market racing setups are run, Several of my personal Tuned modern vehicles(including my LT1) dont use Oxygen sensors, as i have eliminated them.

There is no danger in using an "EFI system" for marine use. For example the coil on plug design eliminates spark plug wires arching probably making the ignition system safer. Or in my case less exposed wire. Running fuel injectors instead of a carb are a huge safety plus, no spilt fuems or fuel, and very very little chance of an atmospheric backfire unlike a carb.
I guess thats why all the high performance boats using the LS motors are unsafe for marine use?

The best option i have right now is, I thinking to use(brainstorming with some hotrod buddies) the shift interrupt matched to the AC circuit relay from the PCM, is uses a .5 volt range, with adjustable settings inside the pcm to change timing based on A/C demand. When the inturruptor grounds its sends that info to the pcm. I can tune it to pull all of the ignition timing when it thinks the A/C button or the "shift interrupt" is on, essentially killing the ignition. people tune their cars using the same tech to retard their timing under boost or nitrous.
(i will be loading a tune to my lt1 vehicle to test this theory).

The only question I would have is how low of an idle must there be for a smooth non damaging shift to occur. I could command say 200 rpm or 50 rpm or even 0rpm when the "A/C" or shift interrupt is engaged.
 

Bondo

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71,012
Re: Who's swapped to an LT1

Im only asking if anyone has done it....Looking for some insight or ideas on how to make it work. Maybe somone to brainstorm with.

I have read plenty of mis-informed posts of why people think the "bottom end wont hold" or how "they are different engines".



Im looking on how to make it work. Am i looking in the wrong place?

I apreciate the regurgatation that it wont work though. (it will)


I am trying to decide between the delteq or the "northstar" ignition sysytem thats used on mastercrafts/aftermarket auto parts. Or using 24x EFI with an ls1 pcm, eliminating not only the optical drive that the mastercrafts used but upgrading to a better pcm and ignition system used on the new LQ4 and lsa marine engines.


No, oxygen sensors are not a problem and havent been for a while.(welcome to the 21s century) Running speed density is how many after market racing setups are run, Several of my personal Tuned modern vehicles(including my LT1) dont use Oxygen sensors, as i have eliminated them.

There is no danger in using an "EFI system" for marine use. For example the coil on plug design eliminates spark plug wires arching probably making the ignition system safer. Or in my case less exposed wire. Running fuel injectors instead of a carb are a huge safety plus, no spilt fuems or fuel, and very very little chance of an atmospheric backfire unlike a carb.
I guess thats why all the high performance boats using the LS motors are unsafe for marine use?

The best option i have right now is, I thinking to use(brainstorming with some hotrod buddies) the shift interrupt matched to the AC circuit relay from the PCM, is uses a .5 volt range, with adjustable settings inside the pcm to change timing based on A/C demand. When the inturruptor grounds its sends that info to the pcm. I can tune it to pull all of the ignition timing when it thinks the A/C button or the "shift interrupt" is on, essentially killing the ignition. people tune their cars using the same tech to retard their timing under boost or nitrous.
(i will be loading a tune to my lt1 vehicle to test this theory).

The only question I would have is how low of an idle must there be for a smooth non damaging shift to occur. I could command say 200 rpm or 50 rpm or even 0rpm when the "A/C" or shift interrupt is engaged.


Ayuh,.... Must Be,....

What are ya gonna use for water cooled exhaust manifolds, considerin' what ya need don't exist,..??
'n how ya gonna deal with the reversed coolin' flows,..??
'n whatcha gonna use for a T-stat housin', that don't exist,..??
 

seeray

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Re: Who's swapped to an LT1

Water cooled exhaust mani's are swappable between the two, the iron or aluminum heads both will accept SBC headers/manifolds.

The idea of reverse flow cooling is it sends water through the heads first, If you understood how it actually worked you wouldn't be asking a simple question. It Changes the flow inside the block. It does enter the ports on the block first but instead of the water/coolant cooling the block first its directed to the heads first then the block, the water pump has four ports instead of the typical SBC 2, it still has a cold return and hot exit just like a sbc water pump.

I am looking into indmar as a simple BOLT ON solution, the thermostat housing is $66.00 from the cheapest supplier ive found.
Indmar also has a solution for the shift interrupt.
 

Bondo

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Re: Who's swapped to an LT1

Im looking on how to make it work. Am i looking in the wrong place?

I apreciate the regurgatation that it wont work though. (it will)

Ok,.. Simple question,....

What are the Advantages of this swap,..??
 

Idlespeedonly

Senior Chief Petty Officer
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Jun 30, 2011
Messages
779
Re: Who's swapped to an LT1

Are you planning to use the optispark?
 

seeray

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May 4, 2012
Messages
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Re: Who's swapped to an LT1

Ok,.. Simple question,....

What are the Advantages of this swap,..??

More power better fuel economy, with the smaller camshaft idle will improve as well as fuel economy. No more pumping the stupid carb to start, it should just take a quick flip of the key, just like a modern car.

Switching to EFI wil safe about 7% in fuel, it will save even More with the LT1s smaller camshaft making better power than most marinized 350s.
So if i went with a carb intake and carb electric fuel pump, it would still be more efficient(not as much) just not as cool as fuel injection.

Other advantages are the abundance of the engine, they are cheap and everywhere.
You could run a vortec, but in my area they are $1k+. I can find Iron headed LT1s for $500 with low mileage all day long.
Far cheaper than rebuilding a mid 80s short block for at-least 1200.

Idlespeedonly, No i would never take an opti to the water. If you re-read i was talking about running efi24x or the delteq system that master-craft uses.
 
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