Whippled 496 HO question

[Phat Matt]

My friend just put one on his 28' Commander cat. We took it out for the first time on Sunday of Memorial weekend. Apparently there was something wrong with the computer program and we had Whipple reprogram it and next day air it to my place in Havasu so we used my boat on Saturday. Before the Whipple he was running close to 65mph. That Sunday in the rough afternoon chop we were up to about 78 or 79 and it was running strong. The sweet spot in the throttle however was not full, you had to back off a bit to feel the power. I was thinking maybe it was hitting the rev limiter and he should try a little bigger prop. He's running a Bravo 1 28 pitch. All in all though the boat ran great.
This past weekend at Mead we took the boat out and it seemed to load up and would have to kind of blow it out after idling out of the marina. Then when we took it for a speed run it just wasn't there. We couldn't top 69 and rpm's where maxed around 46 maybe 4700. The boat also seemed to lose power earlier in the throttle lever meaning you would have to back off on it even more before you hit a dead spot. Offshore Marine in Henderson did all the work and my friend is going to take him out on the lake to check it out, but does anyone here have any ideas on why the sudden loss of power, speed, rpm's and performance?
:confused:
Thanks
Matt

[SHAKEN Not Stirred]

Matt,
The engine may just be getting into "Guardian Mode", which will start by limiting the power by 5% or so and will continue to limit power more-N-more until you get the error cleared.
Or, maybe you may have an injector problem.
Have you talked to Dustin @ Whipple ???
I have emailed him this post just in case.
My Whippled 496 ran a little "Fat" also. When I experianced similar problems as this, we found by looking at it with a scan tool that it had recorded a couple small errors that would slightly retard the performance.
You can only clear them with a scan tool......
Hope this helps.
CJG

[Phat Matt]

Thanks. I'll keep you posted on what happens. So you got yours all fixed and are running strong now?

[SHAKEN Not Stirred]

My motor & boat were used by Whipple for the development of the product. Whipple had it for 6 months and I had the prototype system. My motor is in the Whipple magazine ad's.
I was running 62 with the stock motor, 420 HP and with the Whipple, mine dynoed at 620 HP. I then ran 74.5 on GPS with the extra 200 HP.
It took me a bit of time to get it dialed in, but remember I was the test motor. I ran into the Guardian Mode thing a couple times. If I remember correctly, one was for water temp and I forget what the other thing was.
Anyway, I got it dialed in and it ran fine. I still believe that it is the best and most reliable to get an additional 200 HP out of a stock Mercury motor. I just sold it in December of last year to build a Whippled 565.
I think your friend will be very happy once he gets the bugs worked out.
Let me know what happens.
CJG

[Phat Matt]

Whippled 565? Nice! I think he will be very happy once it's all dialed in. Like I said, the first time we took it out it was great. We were both going to get them together, but I chickened out at the last minute because I want to buy a deck boat (whippled ofcourse) next year, so I thought I would save that money for a down payment. Thanks for the info.
Matt

[SHAKEN Not Stirred]

I now run over 85 on GPS with the Whippled 565. We decided to keep the boost to 5-6 lbs, so she's at about 800 HP. I still have an additional 200HP or so if I ever wanted to be REAL stupid.

[Risky Business]

Originally posted by Christopher Gibbons
I now run over 85 on GPS with the Whippled 565. We decided to keep the boost to 5-6 lbs, so she's at about 800 HP. I still have an additional 200HP or so if I ever wanted to be REAL stupid.
Then you decided 5-6 pounds wasn't enough and purchased another pulley...............Am I correct so far?

[Phat Matt]

Originally posted by Christopher Gibbons
I now run over 85 on GPS with the Whippled 565. We decided to keep the boost to 5-6 lbs, so she's at about 800 HP. I still have an additional 200HP or so if I ever wanted to be REAL stupid.
That's a beautiful engine. Let me know what you get when you add a little boost, because you know you have got to try it at least once. ;) :D

[SHAKEN Not Stirred]

Oh yea.....
Thanks for reminding me........
I'm running 6-7 lbs of boost and making 875 HP.
I forgot I changed the pully.....I'm getting old.
See what you have to look forward to Eric......
Are we still heading to Havasu tomorrow afternoon ????
Call me in the morning !!!
CJG
:cool:

[Risky Business]

Gibbons:
Just decided to leave tonight...Race you up there.

[Just Tool'n]

Have you checked the fuel pressure. Use a mechnical gauge. Make sure you have addaquite fuel pressure at idle, then after you hit the throttle, then at WOT.
Just a thought, also have you check the A/F ratio with an oxyegen sensor?
Best of luck on this.

[Phat Matt]

Originally posted by Just Tool'n
Have you checked the fuel pressure. Use a mechnical gauge. Make sure you have addaquite fuel pressure at idle, then after you hit the throttle, then at WOT.
Just a thought, also have you check the A/F ratio with an oxyegen sensor?
Best of luck on this.
He hasn't had anyone look at it yet but Offshore Marine should look at it soon. I just wanted to get some more advice so he could tell them what else to check. 2 heads are better than one.
Thanks