Difference between Volvo Gi and GXi ??

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cube21

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I searched all over this forum and the web and just CANNOT get any definate answers, so Im hoping you can help.

I need to know the difference between the Volvo Penta 5.0 Gi and the Volvo Penta 5.0 GXi.

I understand that to some extent, they are both "fuel injected". I have read varying things as far as similarities and differences and I just cant come to a conclusion on what is right and wrong. Please help! Were trying to make sure we buy the right engine.
We have already ruled out any carbs as its just not what we want. But I need a comparison between these Gi and GXi models.

thanks all!
-CUBE-
 

superpop

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Re: Difference between Volvo Gi and GXi ??

The X stands for Xstra special.
 

cube21

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Re: Difference between Volvo Gi and GXi ??

I was aware of the difference in HP, and I also know that the Gi is TBI (throttle body injected) and the GXi is MPI (multipoint injected), but being that I dont understand what these mean, Im more worried about the surrounding details.

Anyone know of any differences/similarities between:

-Starting (choke, turning over, etc)?
-Services needed for elevational changes?
-Parts that you need to service periodically (carb parts, injectors, etc)?
-Reliability?
-Torque specifications?

PLEASE!!!
-CUBE-
 

Tail_Gunner

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Re: Difference between Volvo Gi and GXi ??

............


:rolleyes: Knuckle head response was smitten..
 

lucky7

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Re: Difference between Volvo Gi and GXi ??

take this with a grain of salt, as im no expert... tbi has 1 central fuel injection point, like a carb, then the fuel disperses through the intake to diffrent cyls. mpi has an injector for each cyl, fueling can be more precisely metered, the engine can run more efficiently, smoother cold start, better idle, higher hp. i have no idea how well volvos software takes advantage of the superior design of mpi, but the system is potentially better. on the down side, there are more injectors that may someday need to be cleaned, but that wouldnt stop me from choosing mpi.
 

TilliamWe

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Re: Difference between Volvo Gi and GXi ??

Lucky is almost exactly right. TBI (Rochester's name) is "almost" like a fancy carb. It has 2 electronically controlled injectors that spray a constant stream of fuel down on top of the throttle plate that open up, just like a regular carburetor. They are less precise and are not "timed" like MPI can be. But they offer all the real benefits of fuel injection (cause it is fuel injection)... turn key starts, better throttle response, improved fuel economy, in relation to a carb.
I really didn't think the current Volvo engines use TBI anymore. Are you sure about the Gi being TBI? Have you physically seen it?

I have always heard, but have never seen, that on a 5.7GXi, they use roller rockers with a 1.6 ratio. Also the exhaust manifolds on a 5.7GXi are supposedly different, but I can't see it. Maybe these apply to the 5.0 as well?

Regardless, the general concensus is that on the 5.7GXi the extra HP comes at the very upper rpm range and the low end performance is no better than the Gi engines. I could see the same being tru of the 5.0 as well.
 

Don S

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Re: Difference between Volvo Gi and GXi ??

Without knowing the years, full model numbers etc of the Gi and/or GXi, it's hard to say what is different.

Could be nothing more than an ECM change in programming.

PS: The X stands for exceptiional, not extra special.
 

slasmith1

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Re: Difference between Volvo Gi and GXi ??

Without knowing the years, full model numbers etc of the Gi and/or GXi, it's hard to say what is different.

Could be nothing more than an ECM change in programming.

PS: The X stands for exceptiional, not extra special.

if the x is for exceptional then what is the s in gsi for?
 

Don S

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Re: Difference between Volvo Gi and GXi ??

I was just doing some number checking. The only thing I can find different on the Gi engines and the GXi engines is the ECU.
Rocker arms are all 1.5:1, fuel pumps and injectors the same, throttle body and sensors the same, exhaust manifolds and risers are the same.
 

Tail_Gunner

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Re: Difference between Volvo Gi and GXi ??

Lucky is almost exactly right. TBI (Rochester's name) is "almost" like a fancy carb. It has 2 electronically controlled injectors that spray a constant stream of fuel down on top of the throttle plate that open up, just like a regular carburetor. They are less precise and are not "timed" like MPI can be. But they offer all the real benefits of fuel injection (cause it is fuel injection)... turn key starts, better throttle response, improved fuel economy, in relation to a carb.
I really didn't think the current Volvo engines use TBI anymore. Are you sure about the Gi being TBI? Have you physically seen it?

I have always heard, but have never seen, that on a 5.7GXi, they use roller rockers with a 1.6 ratio. Also the exhaust manifolds on a 5.7GXi are supposedly different, but I can't see it. Maybe these apply to the 5.0 as well?

Regardless, the general concensus is that on the 5.7GXi the extra HP comes at the very upper rpm range and the low end performance is no better than the Gi engines. I could see the same being tru of the 5.0 as well.

Me bad...GI does not mean TBI....Seems like i have TBI burnout going on with tying to get my 4.3 done cost effectivley..
 

cube21

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Re: Difference between Volvo Gi and GXi ??

The two engines I actually was comparing were both from 2001. Seems like Im getting some good info here.
I know that with standard carbed engines you need to get certain parts changed in order to use your boat at higher/lower elevations. Is this true for TBI and MPI engines as well? Or will the ECU recognize different air mixtures and adjust...this is one of our primary concerns as well be taking our boat to Tahoe and Powell, as well as regular sea level lakes around our area. We want to make sure we get the right engine.

:)
-CUBE-
 

TilliamWe

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Re: Difference between Volvo Gi and GXi ??

The ECU will make some adjustments. But since it is not a closed loop fuel injection system, it won't be perfect. But there aren't any "parts" you can change to help it. Just propellers. Cause the motor (either one) will be less powerful at elevation than near sea level.
As far as MPI v TBI, you are just going to have to lok at the engines to see which has which. The difference will be Obvious.

DonS, thanks for the parts look up, and showing that the manifolds and such are the same.
 

Don S

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Re: Difference between Volvo Gi and GXi ??

The two engines I actually was comparing were both from 2001.

Were those engine years or boat years? They probably are not the same. A 2001 boat could have a 2000 or a 2002 motor and drive.
That is why Volvo and Mercruiser go by Serial Numbers or Full Model numbers and never mention years.
 

cube21

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Re: Difference between Volvo Gi and GXi ??

The boat years were 2001. Guess Im not really sure what year the engines were...
When it comes down to it I guess I should worry too much about "what type" of fuel injection it is in the boat we buy, as long as it has it.
We might be taking this 01 Ebbtide Campione out for a spin this weekend, it has the Gi. Another boat we looked at, a Glastron, had a GXi, and this is what started all the confusion.
 

Don S

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Re: Difference between Volvo Gi and GXi ??

What you should be checking out is how the 2 boats perform with the power in them. Does it make the boat operate the way you hoped or not. Doesn't even matter what a few letters in the engines model number says or what the differences are between the two. It all comes down to how the 2 boats operate with the power plants in them.
Even if you had 2 identical boats with 2 engines one called a Gi, the other called a GXi, I would bet you would choose the one that ran the best and did what you wanted.
 

IMPBA Racer

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Re: Difference between Volvo Gi and GXi ??

Don,

Is there any performance parts made for Volvo GXi engines?? Or Volvo engines in general?

Thanks,

Mike Hoffman
 

Tail_Gunner

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Re: Difference between Volvo Gi and GXi ??

Yes what ever can be done to a 350 can pretty much be done to a 4.3. The biggest challenge will come from the mefi-3 or 4 software reprogramming. They are open loop systems and run pretty rich, you will need to purchase a software program that will allow you reflash your ecm. Needles to say you will need to be experienced with software programing and have a good working knowledge of fuel injection aka injector pulse width along with timing curves....The programs are about 800 and the first time out id suggest finding a person who is quite fimilar with mefi to build your first retune....There are not many..;)

From there cams, lifter's larger injector's..piston's...maifold's...custom head porting..It's all out there..And then's there's reversion to deal with after your all done. That is pretty simple to deal with after all of the above mods...Simple little thru the hull exhasut system and your home free...Well not quite free, buy something off the shelf could cost you as much as 4000 or you can customize one for yourself for about 500...


Personally i have found it quite intresting and have a guy coming down from the washington area to retune the mefi. Based upon what i have read on ramjet's i believe that better econ will result and maybe a little hp increase. If that all works out i have a list of mod's that should net out 285 hp for about $1800

Like to know more here is a start..

http://www.michaelstractors.com/forum/topic.asp?TOPIC_ID=199
 
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