Need Some Ideal's
 

On Getting more air in the engine hatch on a 271 2000 yr Motor is natural aspirated, its a sleeper ! project , :party-smiley-004: :evilb:

Not sure how much it would help, but putting vents on the back is an idea. This is a low pressure area and should help pull hot air out of the engine compartment. I believe I saw pictures of a 382 / 700HP SCi's with vents in this area.

My 292 has the scoops on the sides and I know the openings under the scoops can be enlarged to help bring in more air. Not sure about the 271.

I have a 382 with 630hp 540's. I tried opening the engine hatch about 4-5 inches while running to see if air flow was an issue.....made no difference on the O2 sensors.

Not claiming to be an expert on the subject, but I'm not sure you would expect to see a change in a O2 sensor reading in that example. The cooler, dense air will have more oxygen, but wouldn't the EFI compensate by richening up the mixture so not much change at the O2 sensor in the exhaust(?)

As an example, if you are running on a 50°F day compared to a 100°F day. Wouldn't the O2 sensor read the same? You just make more power on the cooler day since the EFI can pump in more fuel to burn with the additional oxygen. I dunno, just throwing it out there...:drink:

I was taking readings for potential adjustments to the computers (looking to see if I was running rich). I didn't know what the data would tell me, I was just recording it for the "guru". I wanted to make sure I posted the entire senario so someone with more knowledge could comment. I was told to try it and see if the vacuum readings or O2 readings changed while running....they didn't so I believed it to mean I was already getting enough airflow.

I cut in some of these vents recently on my boat for more air,they look very nice!

http://www.eddiemarine.com/store/car...&p=12238&c=276

Ahhh, I see.

I have been thinking of a test that would be interesting to run and is related to this thread. The temperature of the air going into the engine will tell you how well the engine compartment is ventilated. Using a multimeter you can run a wire and have a thermister mounted at the air intake of the engine with the hatch closed. Then run wide open for a minute and monitor the temperature. If it is a 90°F day and the temperature reads something like 140°F, more air intake should help. If the temperature reading isn't a whole lot higher than ambient, no need for any changes. It would be interesting to test before and after any changes. Has anyone tried this type of test?

Air
 

MORE COOL AIR , into to the intake manifold the more power you will make , a cooler engine will preform better , Looking at a bigger intake manifold and different throttle body , That is why I posed the original post. and Also keep it looking like a sleeper motor ! / Boat ! - looking for some idealolgy with out getting off the deep end with test and meters . :rolleyes: simple is better .

Not to but in here but, I think you're entirely correct. However, if there is no discernable "seat of the pants" increase in performance, doesn't really matter, does it?

More Air
 

My 271 is the same way but I need to open up the vent's and then somehow plum up to my new intake and throttle body for some more H.P./ just do'nt like the vent in the back by the swim platform !:cool: