SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: illmatic505 on November 25, 2011, 11:25:16 AM

Title: EFI with water jacket headers?
Post by: illmatic505 on November 25, 2011, 11:25:16 AM

Will the oxygen sensor still work with water blowing threw it?

Title: Re: EFI with water jacket headers?
Post by: MPKardell on November 25, 2011, 02:52:58 PM

No.  Needs to be hot and dry.

Title: Re: EFI with water jacket headers?
Post by: illmatic505 on November 26, 2011, 08:08:20 AM

So whats the alturnitive to efi? Do they make headers for efi? Thanks!

Title: Re: EFI with water jacket headers?
Post by: Nordie on November 26, 2011, 09:12:41 AM

Seen alot of efi boats efi with water jacketed headers, never seen em with water injected headers...how they do it is beyond me...

Sent from my Samsung Galaxy S 4G

Title: Re: EFI with water jacket headers?
Post by: MPKardell on November 28, 2011, 09:53:29 AM

If it's truly a dry water-jacketed header (all the way through the end of the collector), you *might* be able to drill through both walls in the collector and weld a bung in , assuming you have sufficient access to the inside of the collector to make that weld.  But the pipe is going to run cold, adn O2 sensors like to run hot.

I have tried using an O2 sensor in a short section of dry, "uncooled" pipe (just aft of my logs) as a tuning aid for my carburetted engines, but have trouble getting any kind of useful life out of the O2 sensor before they crap out.

An O2 sensor implies that you're intending to use a feedback fuel injection system.  Not sure if that's really necessary (or desirable) on a jet boat, since the purpose of a feedback system is to keep the F/A ratio near stoichiometric during cruise conditions, for proper function of the catalyst system in a car/truck.

If you go with an open-loop (pre-mapped) system, you don't need an O2 sensor.

But I'm no expert on either one of them.

Title: Re: EFI with water injected headers?
Post by: illmatic505 on December 09, 2011, 11:11:41 AM

oops! my headers are water injected, not water jacket...... thin it would still be a problem?

Title: Re: EFI with water jacket headers?
Post by: HDriderTH on December 10, 2011, 08:16:57 AM

I just installed an old B&M Throttle body injection system on a blown '69 Camaro....no O2 sensor, DID have a small hot wire MAF tho.

Title: Re: EFI with water jacket headers?
Post by: HDriderTH on December 10, 2011, 08:58:15 AM

Also, Dirty Daryl just turned me onto these mechanical pumps for injection. No return required!

www.racepumps.com (http://www.racepumps.com)

Title: Re: EFI with water jacket headers?
Post by: illmatic505 on December 12, 2011, 09:41:19 PM

Cool!!! I picked up a holley 4barrel tbi complete with marine computer. I saw the oxygen sensor and freaked. Thanks to all for the imput!!!!

Title: Re: EFI with water jacket headers?
Post by: TJS Nordic on December 13, 2011, 04:55:30 AM

I ran open loop without an o2 sensor. It is all in the tune and V/E and timing tables.
A dyno session day was a must.

Title: Re: EFI with water jacket headers?
Post by: illmatic505 on December 16, 2011, 10:12:10 PM

dig the pic of the boat! thanks for the info! gettin more fired up for this summer!!!!!