View Full Version : 225 EFI modification
Has anyone made the hood modification as seen in Bass and Walleye Boats May 2002. This is the one were they raise the rear cowling vent and remove hood foam and large air holes have be routed in the rear cowl supports on the inside. This lets the moter get more air and make more power. Seems that it gives you about one to two miles an hour more speed all things being the same other then more air. What are the draw backs? I need about one to two miles an hour more out of my set up. You know the story, brother in laws boat that much faster and I am sick of his s**t. So will this work and what are the trade off's? Do I need to worry about blow motor? I know the fuel milage will suck but is already does as the beast likes to eat. Thanks for your imput. And yes I know Bass and Walleye said these mods are racing only, but thats what I have in mind, racing my brother in law and blowing his doors off. You know boys and there toys.
Dont do it
08-21-2003, 11:28 AM
You will need to re-jet the carbs too. At least that is what I was told by my trusted mechanic. He chucked at that article.
Not to mention it is illegal to modify that motor. (EPA regs) If you do the mods, you can only use the motor for racing.
Dont do it
08-21-2003, 11:28 AM
You will need to re-jet the carbs too. At least that is what I was told by my trusted mechanic. He chucked at that article.
Not to mention it is illegal to modify that motor. (EPA regs) If you do the mods, you can only use the motor for racing.
perchjerker
08-21-2003, 11:54 AM
"rejet the carbs?"
A 225 EFI with carbs?
Sounds like someone took lunch at the bar...
perchjerker
08-21-2003, 11:54 AM
"rejet the carbs?"
A 225 EFI with carbs?
Sounds like someone took lunch at the bar...
Husky
08-21-2003, 12:15 PM
No carbs on an EFI. This modification only provides more fresh air access to the motor ( not ram air or pressuruzed air), no alterations with carbs would be needed either.
As for the EPA regulations, this is not altering any mechanical or electrical part of the motor and I doubt it would be considered an alteration to the motor.
Husky
08-21-2003, 12:15 PM
No carbs on an EFI. This modification only provides more fresh air access to the motor ( not ram air or pressuruzed air), no alterations with carbs would be needed either.
As for the EPA regulations, this is not altering any mechanical or electrical part of the motor and I doubt it would be considered an alteration to the motor.
Here is some info for you, may be more than you want, but here goes.
I have this very same motor and have performed this, along with other modifications, to it and have increased my performance. This of course, was for racing use only.
First, a motor is just a big pump, the more air and fuel you can put in, and at the same time sending more exhaust out, the more horsepower you create. This cowl modification will increase performance but you need to make sure you can increase your exhaust output as well. This can be accomplished with an after market tuner or, in the case of the 225 EFI, simply by cutting off six inches of the stock tuner and shroud and drilling 5 or six 1/2 inch holes in the cavitation plate (on the inside of the lower unit cowl). These two mods will increase your air intake and exhaust flow and should increase your horsepower by as much as 15, sometimes 20 hp.
These two mods will also only be the most noticable during warm and humid air conditions, the reason?, colder, less humid air is denser, and therefore has more oxygen. During warmer conditions this mod helps the engine breath better. You should notice this alreaqdy with your present setup, the cooler the air temp the more power you likely are creating and your boat should be a little faster.
I have also installed blueprinted heads and adjusted engine height for additional performance. Now none of this will make any differnce at all if you are not propped correctly. If your present stock motor is turning at max rpm already, which is 5800 for the 225, then any mod will only make it rev quicker to 5800 but not a faster top speed. If your motor is turning anything less than this than it should increase performance. With my setup as is, I turn a 23 Tempest at 5800 rpm + (I can hit the rev limiter at 6000 rpm during cooler weather) and have increased my top end by 5 mph. Previously, under stock setup, I could only turn a 21 Tempest at 5700 rpm and this is on a 20 foot glass boat.
As far as risks to your motor? I have had 0 issues, but as with any mod, the harder you push your motor the more likely you could create a problem. The key is to keep it under the rev limiter and within factory rpm specs and do this by adjusting prop pitch.
Tazz, Thanks for the infor. I am running a four blade trophy on a glass boat, 223 champion elite. I am turning 5800 rpm's with one person in the boat about 5700 with two. If I read you right there is no reason to change the set up because I am hitting the rev limiter in the summer in the heat of the day so I will not see any increase in speed with this mod. Do you think a three blade prop would help?I have a manual jack plate maybe its time to look at a hydraulic jack plate.Or maybe I should just learn to eat crow, it not like I am running slow at 74.9 mph.Then again my boat is payed off this Dec. and I should go see the bullet dealer or maybe the Allison dealer. Glad it cost nothing to dream. Remember we are just boys with fast toys.
wildgerman
08-22-2003, 11:53 AM
Tazz E-mail me,I need to ask you some questions. Wildgerman fbsheiser@invisimax.com
Abe1, sorry I did not respond sooner, I was fishing over the weekend and just checked my e-mail. I think you have the right idea in regards to jack plate and prop adjustment as your next step. I am not sure where you have your jack plate set, but typically on a boat with a padded hull, which I believe your Champion has, you can set the center line of the prop shaft at 3 inches below the pad. This is measured with the cavitation plate level with the pad, do not measure with the motor at full tuck in as this is typically set at 30 degrees for hole shot purposes. You can go higher but make sure you have good water pressure, depending on the year of your 225 they now have low water pickups built into the nose of the bullet.
Once you have made sure your motor is set the highest, the next step is prop. My personal experience with 3 and 4 blade props is the 4 blade is heavier and generally harder to spin. If you are spinning a four blade at max rpm now, then I would go up a pitch or two in a 3 blade and see what you get. I would keep experimenting with jack plate height and prop pitch until you find a combo that pulls you back to 5500 or 5600 rpms and then you know you have taxed the motor and performance upgrades would help. The upgrades would then push you back up to the 5800 rpm range.
One thing to remember, going up one pitch in prop or 200 rpms will typically give you a couple miles an hour.
Tazz, Thanks for the infor. I will try a three blade prop and work on the jake plate and let you know what happens. Better yet when I get the set up right and beat my brother in law I will e-mail you pixs of him eating crow. Thanks again for the help Abe