Re: How fast should I be going?
 

I have a Sutphen 30. Your boat weighs 5800 lbs.

I am running a totally different set up, so I can`t really offer you any comparison.
I have stock Merc 420`s / TRS / 26P Bravo 4-blades. My props are too big for these engines. I can only get 4100 rpm and then it quits pulling. I`m seeing 64 on GPS speedo.

I`d love to try smaller props to get my R`s up. I`d like to see upper 60`s at least.

Good luck

Re: How fast should I be going?
 

I just reread combo and the 34 dgrees total timing just jumped out.

Do you have factory OE heads ?

If so, the total timing on a performance build usually ends up being 36-38 (some even more :eek: ) because of the combustion chamber design.

Bump up timing two degrees, do a run, note performance, and check plugs for any signs of detonation. I'd probably run 91-92 octane fuel just to be safe.

If performance does jump, try another degree or two and recheck plugs.

Some motors don't respond much to few degrees of timing, but some really wake up. Only one way to find out.

Re: How fast should I be going?
 

I will ttry this for testing purposes. I would be scared to keep it that high. The plug readings showed the timing to be a little high at 35 so I backed it off to 34 and the now the readings are almost perfect.

I saw no performance difference between 34 or 35.

I used to run 87 octane I went up to 89 to be on th esafer side. I will try some 91 or 92 when I up the timing.

Re: How fast should I be going?
 

So I can safely say with fuel gear and 2 people Im right around 7k.

I have a set of 22 bravos that would probably be perfect for you. Too bad your in Texas. I wouldn't mind trying the 26's.

Re: How fast should I be going?
 

Plugs look good. I wouldn't lean it out any. Sorry, just wanted to check.

Re: How fast should I be going?
 

I did lean it out you were right it was a little fat. The pictures are from after I droped it down a little. Unfortunatly it did not net me any gain.

Thanks Rob

Re: How fast should I be going?
 

So what jets did you end up going with? THe last set of pictures looked good.

Re: How fast should I be going?
 

The only things that look out of place on your build are the Air Gap intakes. There are a couple of used HP500, Dart intakes for sale in the classifieds. That's what I'd use.

Re: How fast should I be going?
 

I used to have a 30' Scarab with 420's and TRS drives. It weighed 6800 dry according to the factory. It went 70 with 23 pitch 3 blade cleavers. This size boat always seemed to run well with 3 blade props. With almost 100 hp more a side you should be able to spin 25 pitch Mirages. :confused:

Re: How fast should I be going?
 

Any interest in trying a set of 23P Mirage's? It's what I'm running now and would love to swap and try your 22P Bravo's.