AFR recomended for crusing in boat?

AFR BOAT vs CAR?

Introduction:

I`m new to programming Afr. I do know a lot for engine building, Naturally aspired, Carburators etc. But its the first time I myself is going from Holly carburator to Fitech throttle body system in my boat.

Hardware setup: Chevy petrol 632 Cubic inch ( 10,4L ) , engine-V8. Max rpm 5500. Naturally aspired. And it`s used a lot of money into this machine in balance and

total build up,including increased toleranses for piston / sylinder bore etc etc. Machine vise adapted for marine use.

AFR:

The boat is heavy. The engine is as mentioned naturally aspired, producing 700-750 hp. Top speed like 70 mph.

I will travel long distances also with this boat in cruise speed ( 35- 50mph ). So it is important to find the cheapest / leanest Afr I safely can

drive the engine within the rpm range 3000 - 4500. The output power will probably be like 350- 550Hp in «constantly use»!!! ( Compared to car, do this mean constantly driving uphill with a full trialer )

So yes- . It is extremely hard use in this cruising Rpm. Of course I also is interessed in maximum power :) . This will be in the area 5000-5500 Rpm, but there its not so neccesary to run lean. There I can only think "power" and normal cooling.

Experience- recomondations:

* Do anyone have experience in this matter- Cruising Afr in boat. Is there any pre suggestions comparing to a car.? Do it need to be so or so much richer... Or just follow normal Afr setup or???

Injection setup:

I will have the Fitechs map / Afr sensors. The Afr system can be adjusted as you see attached in the Fitech pictures. And it is the thottle body system.

Privatly I will install exhasust temp. Both Exhaust sensors ( temp and Afr ) will be in the area where all 4 exhaust on one side has got together to one exhaustpipe, like 1,25 feet ( 40 cm) after exhaust outlet. Inside exhaust diameter 3,5inch.

Excited for you answers guys. : )

Best regards. Nils

Personally, because it's so difficult to get best lean torque, I'd be going for around 14.7 (stoich') and 15.5:1, and as much timing as the engine will take while keeping clear of detonation.

As an aside, there's a, IIRC, shop teacher building up something very similar, who posted recently on one of the "engine builder's" channels, was that possibly you? I was thinking off-road/rock crawler, but might have been wrong.

Thx Gord. Super answer : ) Do you mean 14,7 wot and 15,5:1 with cruising?

Double posting no. This is my first post here ever. But if you have a link to the post you mention it be good to look there also at the case and answers.

I have earlier had a crash in this engine. So I want to be safe, using your guys eqperience as help : )

If I go as lean as you suggest. Will I read this as increased exhause temperatur if I start richer and lean up against your suggsetions? Meaning: Can this also be a guide for me that I see a quicker change in increased temperatur as i tune against a "to lean level"?

As told. Im new inte this kind of tuning game. So sorry for asking a lot, hehe. : )

I'd be looking around 13-13.5 under full throttle, around 14.7 for medium load/around half throttle, around 15.5 for light throttle. using a curve with smooth transitions.

Yes, it is similar to towing up a hill, on part throttle.

The post I was referring to was in the comments of a Youtuber's channel, rather than here.

THX a lot again Gord. : ).

BR Nils