Hi all
I am new to the inboard and the madness that is associated. I am asking for a little of the wealth when it comes to volvo legs and setups.
Originaly the boat had a 4.3 1990 non vortec coupled with a DPA 2.30:1 leg
With that engine.. (before the bottom end fell out) used to pull to about 4600rpm 4up, and on the gps achieved 45mph
Now i have just aquired a new vortec lump, again 4.3, from GM to go back in. This one achieving slightly more power to my older unit (according to book) approx 225hp from 190hp.
One thing i am after is a faster cruising speed and a bigger top end. I know the boat is capable of handling this as i have had numerous outboards on smaller, less well built boats and achieving closer to 65mph.
So i have been looking into larger engines and lowing the gear ratio to 1.78 or similar..
but... i have data from volvo penta website that seems to suggest that even with a massive power engine and 1.78 ratio leg that the best achievable is 55mph odd...
when i glanced over at the sx section of the same data sheets i notices a huge difference.
comparing the same engine. the lowest power 4.3 as i would like to stick with this unit if possible due to space, the preformance seems contradictory to info i have attained previously.
4.3 GL with sx 1.85:1 drive and 23inch prop achieves 58mph
4.3 GL with dpa 290 1.95:1 drive and the longest prop achieves 50mph
i know that ur going to tell me that the ratios are different but why are there not listing 1.78:1 drives on dpa until 7.4litre engines. Even then they are only achieving 52mph..
my question is.. has anyone got experience of this? is the volvo data perhaps inaccurate?
and can you replace the gearbox to an sx easilly or is it a full leg and gimball replacement?
also looking at the DPS drive higher speeds are achieveable, again is this an option for a swap out? whats required in this?
any other suggestions or advice is greatly appreciated on this matter.
thanks in advance for the advice..
I am new to the inboard and the madness that is associated. I am asking for a little of the wealth when it comes to volvo legs and setups.
Originaly the boat had a 4.3 1990 non vortec coupled with a DPA 2.30:1 leg
With that engine.. (before the bottom end fell out) used to pull to about 4600rpm 4up, and on the gps achieved 45mph
Now i have just aquired a new vortec lump, again 4.3, from GM to go back in. This one achieving slightly more power to my older unit (according to book) approx 225hp from 190hp.
One thing i am after is a faster cruising speed and a bigger top end. I know the boat is capable of handling this as i have had numerous outboards on smaller, less well built boats and achieving closer to 65mph.
So i have been looking into larger engines and lowing the gear ratio to 1.78 or similar..
but... i have data from volvo penta website that seems to suggest that even with a massive power engine and 1.78 ratio leg that the best achievable is 55mph odd...
when i glanced over at the sx section of the same data sheets i notices a huge difference.
comparing the same engine. the lowest power 4.3 as i would like to stick with this unit if possible due to space, the preformance seems contradictory to info i have attained previously.
4.3 GL with sx 1.85:1 drive and 23inch prop achieves 58mph
4.3 GL with dpa 290 1.95:1 drive and the longest prop achieves 50mph
i know that ur going to tell me that the ratios are different but why are there not listing 1.78:1 drives on dpa until 7.4litre engines. Even then they are only achieving 52mph..
my question is.. has anyone got experience of this? is the volvo data perhaps inaccurate?
and can you replace the gearbox to an sx easilly or is it a full leg and gimball replacement?
also looking at the DPS drive higher speeds are achieveable, again is this an option for a swap out? whats required in this?
any other suggestions or advice is greatly appreciated on this matter.
thanks in advance for the advice..