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318 Chrysler Motor Change

Ward

New member
I own a 24' Uniflite "Salty Pup" with a 318 Chrysler inboard abd Borg Warner transmission. I am thinking of changing to a fuel injected V-6. My goal is to add more power at a lower RPM and improve fuel economy. Has anyone had experience with this application?
 
Hello Ward,

I also own a Uniflite. 27' Cruiser with twin 318's. I live in Western Washington but my boat is in SE Alaska. I know several people up their that have inboards with fuel injection. The only issue besides the cost of the changeover is the salt air degrades electronics. Recently I spoke with a local fireman in Sitka and he has twin mercs fuel injected that are computer controlled. He told me if he had to do it again he would stay carbureted. The salt air is giving him fits with his computer. I have no personal experience with what you're asking but if you decide to get ride of your engines/trannys let me know. It looks like we live in the same State. Take Care

Russ
 
I own a 24' Uniflite "Salty Pup" with a 318 Chrysler inboard abd Borg Warner transmission. I am thinking of changing to a fuel injected V-6. My goal is to add more power at a lower RPM and improve fuel economy. Has anyone had experience with this application?

Ayuh,.... A 4.3l fuel injected does 'bout 225 hp,.... 'bout the same as a 318,...

No way yer gonna get More horsepower, at lower rpms,....
'n the fuel burn won't be much lower, as it takes some many gallons of gas to move a hull through the water, at whatever speed ya choose,....
Regardless the motor, or it's induction,...
 
It takes torque to spin a prop and torque comes from displacement. I have a 1969 ChrisCraft Lancer cuddy with a 20 degree deadrise hull. It came factory stock with a 283 CID 185 HP engine. It burned 10+ GPH at cruise. I replaced the engine a year after I bought the boat with a 5.7L (350CID) 260 HP carbed engine ( I don't like all those electronics on an engine in salt water either and I'm an electronics design engineer by trade). The new engine with better torque ( and a different prop) planes and cruises the boat at substantially lower (by 600) RPMs and burns about 6.5 GPH doing it. One of the factors that contributes to this improved fuel burn is that the original engine was raw watercooled and ran a 130 ish deree T'stat, while my current engine is FWC and runs a 160 T'stat. Better efficiency @ higher engine temp. BTW, the Lancer's dry weight is about 4000 lbs and Deep V hulls are notorious gas eaters..
 
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I agree with Bob....... you'll want to make torque!

A Chrysler 360, with a good quench dimension built into the combustion chamber, will make more than what a FI 4.3L can make.

I'd also recommend staying away from the more "detonation" prone lower rpm range!
For best results, keep the hull up on step..... and a tad bit more.
If propped correctly, that will put you in the correct rpm range, reduce engines loads and will offer you better on-step fuel economy!


.
 
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