new intake on 4.3

W

wyoboat

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Edelbrock makes a 4.3 four barrel intake manifold that they claim is worth 18 hp over a stock marine. I was thinking of getting this and a carb to match it has anyone on here used this set up? I know it is probably a wast of money but i can't help but tinker on my toys.:)
 
M

machz1000

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Re: new intake on 4.3

hope to hear how you make out with it.I have a set of vortec heads edelbrock intake carb and cam to go on mine
 
achris

achris

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Re: new intake on 4.3

Just to let you know what that 18hp will get you... I had a 1994 4.3LX that made 180hp and the boat did just on 40knots. I replaced that engine with a 2006 4.3MPI and the top speed is now 43.2knots. For 40hp I got just on 3 knots increase. FYI.

Chris.........
 
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wyoboat

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Re: new intake on 4.3

yea i know, that's why i said it's probably a wast of money. But i think i may do it anyway. wont know till you do it. I would think the carb swap otta help a bit to.
 
scooper77515

scooper77515

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Re: new intake on 4.3

Bigger carb on better flowing intake will most likely suck more gas...
 
Volphin

Volphin

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Re: new intake on 4.3

I have done this upgrade. Eddy 2111 and 1409 combo. Here is what I experienced... 1) Regardless of the larger carb, I got much better fuel economy at cruise. 2) The engine was not straining to breathe any longer. 3) +6 mph.

I have since upgraded to Vortec heads and am using the 2114 and 1409. Much more power across the band.

A 2111 can be found on ebay for $99 used usually.

HTH

V
 
achris

achris

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Re: new intake on 4.3

fossill said:
Out of curiosity, how much money did that 40 hp/ 3 knot increase cost you?
Click to expand...

The cost of changing over from the 4bbl carb engine to the MPI engine ended up being $3,000. But for that I also got a 12 years newer engine and better fuel economy. Was it worth it? Definitely not! This is the engine that has been cracking timing covers. See THIS thread. And I currently have it out again now, for the same problem. It just will not be fixed.... I want my old engine back...
sad0004.gif
Mercury as still being uncooperative. So, no surprise there.

Chris........
 
180shabah

180shabah

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Re: new intake on 4.3

scooper77515 said:
Bigger carb on better flowing intake will most likely suck more gas...
Click to expand...

And this is based on what????

better flowing intake (and or exhaust, for that matter) = more efficient engine opperation - less pumping loss

Replaceing a 2bbl with a 4bbl does not equal higher fuel burn - properly tuned is properly tuned

Your right arm ultimately controls fuel use - as long as cruise speed remains the same - so should actual fuel use...
 
Bondo

Bondo

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Re: new intake on 4.3

wyoboat said:
Edelbrock makes a 4.3 four barrel intake manifold that they claim is worth 18 hp over a stock marine. I was thinking of getting this and a carb to match it has anyone on here used this set up? I know it is probably a wast of money but i can't help but tinker on my toys.:)
Click to expand...

Ayuh,... My questions are,... What's on it Now,..?? What vintage is the motor,..??
 
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wyoboat

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Re: new intake on 4.3

it's a 20ft larson 1988 205 horse 4.3 with a stock manifold and a Q-jet carb that by looks of it has to be at least a 650cfm. so i think I'd be going down i cfm's. I'd like to put a 500cfm on it. Do these carbs have to be "marine" what is the difference?
 
180shabah

180shabah

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Re: new intake on 4.3

ABSOLUTELY!!! must be marine....

Auto carbs go BOOM!!!!:eek:
 
J

jkust

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Re: new intake on 4.3

I've seen a few guys on here do the conversion. I haven't been wowed by the results. Your 88's hp isn't rated at the prop like the vortec engines are. If it was your 205 hp is the most you could expect from that conversion on a vortec 190hp. As for more fuel usage, I'd only expect slightly more usage with the secondaries opened.
 
Volphin

Volphin

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Re: new intake on 4.3

wyoboat said:
it's a 20ft larson 1988 205 horse 4.3 with a stock manifold and a Q-jet carb that by looks of it has to be at least a 650cfm. so i think I'd be going down i cfm's. I'd like to put a 500cfm on it. Do these carbs have to be "marine" what is the difference?
Click to expand...

The Eddy 1409 is rated at 600cfm. More cfm on a V6 will make for one lazy engine... it is really about air/fuel velocity down the runners, not cfm. Yes use a marine carb.

V
 
J

John_S

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Re: new intake on 4.3

wyoboat said:
it's a 20ft larson 1988 205 horse 4.3 with a stock manifold and a Q-jet carb that by looks of it has to be at least a 650cfm. so i think I'd be going down i cfm's. I'd like to put a 500cfm on it. Do these carbs have to be "marine" what is the difference?
Click to expand...

The q-jet that is on there is 750cfm. Mercuiser used that and a 600cfm weber. Neither is too much for the engine, because they both are vacuum secondaries which will only flow what you will need. The Edelbrock 1409 is a very close copy of the merc weber, and there is a tuning kit for 4.3L.

Given your current carb is the q-jet, you will not see any noticable performance increase, unless something is not working correctly with your set-up today. If the q-jet was tuned correctly, it is probably slightly better at fuel efficiency with the small triple venturi primaries. You also would not need to change the intake. Merc used spreadbore to squarebore adapters, and you could as well.
 
scooper77515

scooper77515

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Re: new intake on 4.3

And this is based on what????
Click to expand...

First off, re-read my post. I said "most likely" because I know that there are some people out there who can fine-tune and get good, if not better gas mileage. I ran a 600 cfm on my Maverick 302, getting 1 mpg if I nailed it hard, or 20-22 mpg if I drove like a granny.

This guy wants more power, and more speed. Gonna generally take more gas to get it. 2bbl, 4bbl, or whatever.

I doubt he wants to soup up the motor and then keep it under 1800 rpms from here on out so he can maintain his current gas mileage....

Don't just try to stir up an argument or play devil's advocate. Because you KNOW that "generally" and "most likely" if he slaps a 4-bbl and intake on this engine, he will use a touch more gas while trying to get a few more ponies out of it.
 
Volphin

Volphin

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Re: new intake on 4.3

FYI for those interested: Stock manifold is 28 lbs. Eddy 2111 is 11.9 lbs.

V
 
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