LS speed density
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LS speed density
Hi all I am new to the forum so maybe this post is in the wrong link...Anyway I have an ls3 in my ski boat currently running on a carb and msd box setup, I would like to change it to efi but am having a hard time figuring out how to get around the wet exhaust manifolds (no MAF or O2 sensors), basically running a speed density open loop system. Has anyone run into this and come up with a solid fix? I saw one post from a few years ago by wasted income that was just about exactly what I'm talking about, any help would be greatly appreciated!
Thanks
Will
Thanks
Will
#3
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I don't know what type of manifolds you have but there are spacers out there that slip into a joint to accommodate an O2 sensor such as the Wags Engineering unit. Or you can get one made.
http://wagsengineering.com/products/...sensor-spacer/
There's various EFI TB setups that will plug and play. FAST, Holley Sniper, etc.
http://wagsengineering.com/products/...sensor-spacer/
There's various EFI TB setups that will plug and play. FAST, Holley Sniper, etc.
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I saw those manifold adapters and actually emailed wags but didn't get a response..I would like to just drop a factory intake harness and ecm in it, if I can run o2 then that makes it easier but I haven't come up with a solution yet, thank you for your responses
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Nothing wrong with open loop speed density. Same as the efi merc engines. Use the factory ect/iat tables. You will need to rig up at least temporarily an o2 sensor to get the VE and PE dialed in. Once there you're good.
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This may be of use.
http://www.offshoreonly.com/forums/d...setup-how.html
If you're thinking of dropping a factory merc system on there that would be a major pita, and many folks pull those off and put a carb on it.
http://www.offshoreonly.com/forums/d...setup-how.html
If you're thinking of dropping a factory merc system on there that would be a major pita, and many folks pull those off and put a carb on it.
Last edited by Baja Rooster; 04-05-2017 at 10:02 PM.
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I tuned my LS jet boat OLSD. I made a temporary dry tailpipe to accomodate a wideband O2 to get the tune dialed in. The good news is that EFI tuning on a boat is significantly easier than a car. You basically have just a diagonal line to tune on the 3D VE map instead of a larger portion of the map since there are no gears to change, so the load vs rpm stays pretty linear.
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Was there a reason you decided to go speed density instead of MAF? Space or water intrusion? I am having a hard time finding a tuner that will touch something like that...and I have no expierience in EFI live or hp tuners personally. Kind of stuck at the moment trying to figure that part out, do you know anyone/do you tune for others?
Thanks
Thanks
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I have a LQ4 twin turbo in my boat, running Holley HP EFI in speed density. I would figure out away to get an o2 sensor in place otherwise you are just guessing when it comes to EFI.
If you can get a 02 sensor in place you can running self learn and the boat will "tune" itself.
Holley (among others) makes a really nice fuel injection set-up that just replaces the carb(s).
This is the way I would go
https://www.holley.com/products/fuel...parts/550-511K
You will need todo a elec fuel pump, and strongly recommended an 02 sensor, once you have it tuned in you can disable self learn and just run it off the base map(speed density).
I have mine set-up to only running closed loop above 2000rpm, and only adjust upto 10% of the value.
If you can get a 02 sensor in place you can running self learn and the boat will "tune" itself.
Holley (among others) makes a really nice fuel injection set-up that just replaces the carb(s).
This is the way I would go
https://www.holley.com/products/fuel...parts/550-511K
You will need todo a elec fuel pump, and strongly recommended an 02 sensor, once you have it tuned in you can disable self learn and just run it off the base map(speed density).
I have mine set-up to only running closed loop above 2000rpm, and only adjust upto 10% of the value.
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Was there a reason you decided to go speed density instead of MAF? Space or water intrusion? I am having a hard time finding a tuner that will touch something like that...and I have no expierience in EFI live or hp tuners personally. Kind of stuck at the moment trying to figure that part out, do you know anyone/do you tune for others?
Thanks
Thanks