bobl

I just finished dynoing my engine. So now we have some more very good data to play with. First remember my 28 Heat Mid cabin runs a consistent 86 with a best of 89, running in 95+ degree weather at around 800 ft. elevation. I've never made a pass in it with the temp below 90 degrees. With that said, I pulled the engine out of the boat and put it straight on the dyno, changing nothing. The dyno sheet is attached. What I find interesting is that peak HP occurred at 6100 RPM. I never turned it past 5600, so I was leaving a couple of MPH on the table. I'm rebuilding it this winter and doing some improvements. The second dyno pull is with 2 more pounds of boost. It likes boost!

Steve Zuckerman

Bob,
Aren't dynos the ****! The second chart is sweet. Just prop for 5800 and set the limiter at 6000 and let her eat ............
What are you planning for the winter?
Looks like all you needed was the dyno sheet and the smaller pulley !
Regards,
Steve

bobl

I really thought it would peak around 5800 with that cam and heads. I'm sending the heads to Jim V for a serious massage. I want to lower the compression a little and run more boost. I'll install a cam more suited to a supercharged engine. Mainly I have to freshen it up because one cylinder was having a lot of blowby, so it was time. It has over 300 hours on it. Looking at the second dyno run it looks like I am running into a flow restriction somewhere because the boost shot up and power fell past 5600 RPM. I think the heads are too small. They were configured for it being naturally aspirated.

Steve Zuckerman

Bob,
Looks like a 900HP summer 07 for you ...............
I am proceeding with modifying my 575 this winter with Dart/marine aluminum heads, roller cam (suggestions welcome, am getting recommendations from KE and RM Builder), and raising compression to 8.5 from 7.5 static.
Boost should be 7 PSI intercooled (which it is now).
I don't know how my drive is going to like this, but I think I will like it a lot ..................
Regards,
Steve

SeaRay Jim

Wow. And that's before freshening it up!!!! Can't wait until next summer.

It'll be really interesting to see "another" dyno to compare!

When we looked, I had room didn't I?

bobl

Room?? for a supercharger???? Yeh, you've got plenty of room. Especially in your house after Mary leaves....LOL

SeaRay Jim

LOL, so when can you start?

boatingbent

LMAO.......

So you think if we pull my engine out again this winter Brenda might leave me???????????????????????????????????????????????? ?????????????? NOT!!!!!!!!!!!!!!!!

bobl

Here's a link to the video of this dyno run if anyone is interested.

http://media.putfile.com/FTM-800-EFI-dyno-test

Knotwright

Bobl,

Look at the fuel column on your dyno sheet.
Fuel goes way up, your power does not, yet your AFR is good.
The fuel is going somewhere.

I think your cam overlap/center/duration is pumping the fuel into you exhaust.

I also noticed that you are burning a bunch of fuel to make 820Hp..Again I point the finger at your cam.

I have been down this road before and had the same thing happen....Then again, my wife says I am a moron!