Circa 2008 4.3 GXi (SX-A) Possible to increase power/performance?

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FTP20

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On a 2008 (could be an '07 or '09, can't recall) Stingray 195X bowrider with a Volvo Penta 4.3 GXi-J and SX-A 1.66 outdrive, are there any simple ways to improve engine output and performance? The throttle response off-idle is quite soft and the boat struggles to pull a ~200lb slalom skier out of the water.

My engine knowledge is from the car world so I don't know if there are options for ECU/PCM upgrades/tuning, a better air intake, etc on a boat like with a car/truck?

I did change from the original aluminum 14 x 21 four blade prop to a Turning Point Hustler 14 x 19 four blade. This seemed to help a little bit with the hole shot but maybe I should have gone with a stainless prop and solid hub instead of the aluminum / rubber combo?

FWIW, with the new 14 x 19 prop, in perfect conditions, the boat will reach a GPS-verified 48mph (78km/h) @ ~4800rpm. In reality we will never need to operate the boat over ~40mph.

*File photo attached - not the actual boat
 

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QBhoy

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Hi. Quite a common issue, on boats in the 18-20ft class with the 4.3 gxi/mpi.
They require a very carefully and well selected prop to see them at their best. They really can be gutless down low with too much prop pitch. It’s a very fine balance to get it as good as she can be. Having propped a couple of regal 1900’s with the 4.3 mpi merc version…I found them at their best all round when they can only just touch the limiter at about 4900/4950ish top end (usually about 50 mph gps or a little over on them). In their case, it was a 19” tempest plus 3 blade that performed the best, out of the props I tried. Be similar ratio to your VP. So I’d suggest a really good stainless prop that will allow you near or just on the limited top end…giving the best mix of top end and low down performance. That’s if you want it all round good and able. Hope that helps. But yeah…it’s a commonly found thing on these particular engines for sure.
 
Scott Danforth

Scott Danforth

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you cant squeeze any more juice from a 4.3 without a supercharger...... the motor is currently on the very edge of reversion and detonation and no way to get more naturally aspirated power out of it. and for the price of a supercharger, you can sell your current boat, buy a bigger one with a bigger motor.
 
Bondo

Bondo

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FTP20 said:
On a 2008 (could be an '07 or '09, can't recall) Stingray 195X bowrider with a Volvo Penta 4.3 GXi-J and SX-A 1.66 outdrive, are there any simple ways to improve engine output and performance? The throttle response off-idle is quite soft and the boat struggles to pull a ~200lb slalom skier out of the water.

My engine knowledge is from the car world so I don't know if there are options for ECU/PCM upgrades/tuning, a better air intake, etc on a boat like with a car/truck?

I did change from the original aluminum 14 x 21 four blade prop to a Turning Point Hustler 14 x 19 four blade. This seemed to help a little bit with the hole shot but maybe I should have gone with a stainless prop and solid hub instead of the aluminum / rubber combo?

FWIW, with the new 14 x 19 prop, in perfect conditions, the boat will reach a GPS-verified 48mph (78km/h) @ ~4800rpm. In reality we will never need to operate the boat over ~40mph.

*File photo attached - not the actual boat
Click to expand...
Ayuh,..... Welcome Aboard,..... The Best way to get more power is to pull the 4.3l, 'n drop in a 5.7l,....

There's no chip changes, nor easy bolt on answers to squeeze much more outa the 4.3l,.....
 
F

FTP20

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Joined
Aug 2, 2022
Messages
6
Bondo said:
Ayuh,..... Welcome Aboard,..... The Best way to get more power is to pull the 4.3l, 'n drop in a 5.7l,....

There's no chip changes, nor easy bolt on answers to squeeze much more outa the 4.3l,.....
Click to expand...
Case closed! Sounds like we can close this thread and I will focus on prop options. Thanks
 
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