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-   -   Bbc blower motor help! (https://www.offshoreonly.com/forums/general-q/357137-bbc-blower-motor-help.html)

Daytona25 03-13-2019 05:14 PM

Don’t worry about hi jacking the thread, I’m learning too!!

SB 03-13-2019 05:55 PM


Originally Posted by LTZCrew (Post 4677017)
i was going to send you a pm to pick your brain so i dont hi jack this thread haha, stock 575sci units with the pods removed

Figure somewhere around 750cfm or so per throttle body. They have 2" bores and now no injectors over them to impede airflow.

Daytona25 06-12-2019 07:27 AM

https://cimg2.ibsrv.net/gimg/www.off...6d7b4d4f1.jpeg

14 apache 06-12-2019 09:18 AM


Originally Posted by Daytona25 (Post 4691465)

power looks pretty good. I don't know why he did 600rpm a sec. it would be nice to see o2 reAdings I see BSFC is very high on the top end may be power there if it's that Rich.

MILD THUNDER 06-12-2019 09:35 AM


Originally Posted by 14 apache (Post 4691491)

power looks pretty good. I don't know why he did 600rpm a sec. it would be nice to see o2 reAdings I see BSFC is very high on the top end may be power there if it's that Rich.

Id think by looking at the bsfcs, that thing is really rich! Afrs prob in the 10s

Daytona25 06-12-2019 11:02 AM

He did not have the ability to hook up o2 sensors so I’ll have to fine tune the rest out in my boat! Still happy with the power for the cubic inches though so far!! 3* timing was worth 50hp!

14 apache 06-12-2019 11:15 AM


Originally Posted by Daytona25 (Post 4691514)
He did not have the ability to hook up o2 sensors so I’ll have to fine tune the rest out in my boat! Still happy with the power for the cubic inches though so far!! 3* timing was worth 50hp!

be carful tuning for power with timing especially dynoing it at 600rpm a second. Watch how far down the ground strap it burns. There is a big difference at 600rpm to 100rpm a second. What heat range plugs you run on dyno?

Daytona25 06-12-2019 04:04 PM

Ground straps still showed it would have probably taken more timing than we put in it, started at 29* and could hardly tell the tip of the strap was colored then I slowed the blower down and took 2 jet sizes out of front and back of both carbs and made a second pull, it picked up tq and lost a few ho but still had a flat spot around 5800rpm so I bumped timing up to 32* and the motor pulled cleaner and sounded a lot better still shows timing mark before the elbow on the ground strap but that pull picked up another 10tq and 50hp and had a nice smooth power curve with no dips or stumbles so I left it there plan on checking plugs and air fuel ratio once it’s in the boat?

Daytona25 06-12-2019 04:05 PM


Daytona25 06-12-2019 04:05 PM

That’s first pull at 10% overdriven with 29* timing and 82 & 86 jets


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