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GEOO
09-12-2000, 07:06 PM
BigGrizzly, I need some tuning help.
I had my engine tuned on the dyno. The engine didn't feel as powerfull as the dyno indicated. I checked the A/F ratio with a Lap Top hooked up to my ECU. I was getting readings of 9.1 to 9.5. My guess is the fuel pressure must be higher in the boat then it was on the dyno. I ordered a fuel presure gauge to help. In the mean time; I adjusted the fuel map and the closed loop system to move the A/F ratio to 12.7. The boat ran faster. How lean should I go? How can I tell if the motor starts to run too lean? I don't want to put a hole in the piston!! I checked the plugs; how can you get an accurate reading? Thanks. GEOO

BigGrizzly
09-12-2000, 10:28 PM
I would like more information. The only thing i know about your engine is, it is injected and it had 575 hp on the dyno. 9.5 is way too fat. 12.7n is closer, 12.5-13.5 would be the best If the load is light, cruise can be real lean. Question, do you know how to read plugs? In a boat you can't hear or feel detonation or lean untill it is too late. On a eailer post you told Chris the Crane cam you used on the 383- good move. Before I step in it big time give me some specs, timing (both idle and full any built in retard) comp ratio, injector size cam specs (especially duration and overlap if possible) . I hope you have forged pistons. I was just puzzled carb gave you 602 and injector 575, what gives?
I love your boat and drive. You really took a big chance and MADE it work. Some day I would like a ride in it. No wise cracks, he's gone faster and longer then most people .
Jusr a note. I was over at Grimes this afternoon. He had his 24 V hull brand x boat with a small block with a very large blower which puts out well over 700hp. your only 10 mph away from him.

[This message has been edited by BigGrizzly (edited 09-13-2000).]

GEOO
09-13-2000, 06:47 AM
BigGrizzly,
The engine liked 35deg. when on the dyno. I don't have a cam card but it's about 255/262,
613/627, 112, solid roller. Have 6.125" rods,4" stroke. Alum heads, 10.5:1, 232cc runners, flow 308 @ .6. Jessel shaft mounted rocker arms. With current prop runs 5500-5800. Engine was set up to be propped @ 6000. I know the concept of reading plug. If the are black too rich, white to lean. It's easy to see the plugs are black, but what do white plugs look like? How do you look at the plugs? Do you need a lighted magnified Glass type of gadget? or with your bare eye?
The carb was a basic Holley carb he took off another engine and just put on my intake. He left my injectors and everything in place. The carb did have a 1" spacer under it. I tried adding a spacer under my throttle body, it seams to increase power. I was told the carb has better fuel vaporization and the fuel entering the intake sooner has a cooling effect on the air making a better charge. GEOO

BigGrizzly
09-13-2000, 05:55 PM
It was good talking to you this morning. Im going out this weekend, if i can I will get agood plug chop and send it to you for a comparision, with a complete explanation. I you have any other questions just ask.

Emmo
09-13-2000, 09:52 PM
GEOO- How hard would it be to tap your exhaust for EGT? Figure out which cylinder on each side tends to run the leanest and put the EGT sensor as close as possible to it.

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Emmo mailto:emmette@emmette.comemmette@emmette.com</A>

Barry Phillips
09-22-2000, 07:57 AM
Big Grizzly:
Geoo took me out for a spin on Lake
George. This boat rocks. I think the
lenght of the drive acts like an extension
box, seemed stable at 80+ mph, the only
thing to look out for is cross wakes.
Geoo reads the water really well and
dose not take stupid risk. This boat feels
lighter than my Classic 18 and one has
the feeling that WOT from mid -range
will rokett this boat big time. I think Geoo
can find 90mph with some more tuning
and flat water.
I wish him luck:
SO-SLO