FlyFast

Paul

I have a 96 chaparral with a sbc. My motor died and I added alot more ponies. I found my top end with one person on the boat and little gas was much faster. My top end with the boat pigged out with folks and fuel runs the same as my last motor. My new motor is alot quicker to plane and up tto speed. I figure there is alot to do with the hull to get much more additional speed.

I don't understand drag with a planning hull but someone on this board could probally explain why it takes so much more power to go a little faster.

Waterfoul

I believe Tyler Crockets "Cam Upgrades" also include exhaust and a re-mapping of the ECU. I know a guy in Grand Haven who did the same thing to the 502 in his 27 powerquest and gained nearly 7 mph overall with a light load. He had EMI exhaust on his. I know that the upgrades I made this spring were good for about the same 100 hp as you and I got a 6 mph increase. Older boat, heavier boat, no steps.....6 mph gain. You're missing something. Post some numbers. RPM, mph, cam specs, what exactly did you get from Tyler, etc..... Tyler has a GREAT reputation for getting hp from big block Chevy motors....I'd be surprised if you didn't get somewhere near the 100 hp he claims his kit gets.

Mike

PAUL HARRIS

1. Thanks guys for all of your responses to my dilema.
2. Here are some more specs. We installed 2.250 intake valves 1.90 exhaust valves, a three angled valve job, milled the heads .020, a cam motion cam w/ .574 intake, .558 exhaust lift duration of 223intake 230.5 exhaust w/ 114 seperation, roller rockers vortech flame arrestor. Eddie Marine thunder manifolds and stainless risers. Tyler did the mapping of the computer.
Stock my bout ran 68mph on gps @5150 rpm w/ 23 mirage plus
First attempt after mods w/ same prop boat ran 67mph @5000rpm Next step was to increase fuel, so I bought a cool fuel system from Tyler. It replace the vst tank and old fuel pump with new electric pump cooled by lake water.
latest attempt w/ new fuel system the boat didn't get over 65mph ( I think now it's running to rich-need to turn down to approx. 42psi next time out)
The only dyno I did was @ grand sport which doesn't tell squat
Anyone out there know where to dyno in norhtern IL.
I did try several propellars from John @ DAH propellers
my speed was always the same from a 23, 25 ,27 3 blades, to 24,26 4blades. Only slight fluctuations in rpm
Tyler suggested I post my problem to the panel and hopefully someone has an idea. Thanks again, slow Donzi

Ric232

Paul,

I was considering the same Tyler package for my 232 Baja w/454 Mag MPI. Maybe I won't.

On your camshaft, you said lift of .574" intake and .558" exhaust. Is that exhaust number right? Sounds like the numbers might be reversed.

Also, do you know what your compression ratio is now with the milled heads?

mcollinstn

any chance that you changed to different (nonspiral core) plug wires? That, or another source of electrical "noise" could be making your TboltV think you are knocking, and the computer may be pulling out all your ignition advance... You never know what little connection somewhere may be intermittent when you yank and reinstall a motor..

Offshore Addiction

try putting a stock computer back on

turbo2256

You might need some of the smaller port aftermarket cylinder heads ... assuming you have square port heads you appear to have the perfect set up for the oval port head engine with some hot heads. Try a pair of the Canfield or Brodex small "square" port
heads say like the 310 Canfields.

check300

Tom Earhart does a lot of dyno work on boat motors. Has done several for OSO members. He is located in Gun Lake Mi which is about 25 mi. north of Kalamazoo. There is no better way to get a motor dialed in then on a dyno. His phone number is
269-795-9679. Good Luck!
Bill

FBRONCO

I put the same kit on my 95 24 outlaw with a 454 mag in it. Did all the work myself - except for the head work. I only gained about 3 mph in top end. Runs good though.

audacity

did you dial in the cam???....did you do it on multiple lobes???...more on the intake side...wow, that's strange