Mercury 500 EFI
 

What is the safest, biggest, cheapest, H.P. gain?

How many hours on the engines currently?

Hello guys Im a new member and I was told that this was the best site to get questions answered. Im running triple 500 efi's in a 2004 Baja 40' Outlaw. I dont want to go into the motor but I would like to add some bolt-ons. Any ideas?

I have approximately 245 hours on the them. They are bone stock

Are you running 500's too?

I would personally go with either a Vortech or Whipple system. The Vortech is likely to cause more problems with your exhaust. I would not do anything to them before I had them freshened up.

Nice boat, I have had some seat time in an identical setup.

You will find that you will need to rephrase your question to this:
"What is the safest, biggest H.P. gain?"

Thanks, Im admiring your Excalibur as well. Yeah I was thinking that I wanted to stay away from chargers for now. At least until like you said after they were freshened up. I was thinking about a ECM reflash, new throttle body, MSD ignition, and flame arrestor? I know the HP gains are not as significant but I think it is a lot safer.

Save your money.

The gains from these things arent worth the money spent. That is what I was afraid of !!!!

I have a new intake top that will be available soon that has a 2000 cfm throttlebody built right in the top that will bolt right on your intake. I tested one last week on a Merc 525 and picked up 18 HP and 18 #of torque at the same RPM's. I also can reprogram your ecu.

there are different things you can do and in stages to boost your horsepower. Many builders can take the 500 and get it up to 560-580 and not break the bank. you can pretty much make it a 525 by adding aluminum heads as well, just wont have closed cooling. dont be discouraged, you have a great base to build from. contact the following shops.

JC performance
Richie Zul
Precision Marine
Tyler Crockett
Gellner Performance
MDG Performance

All of these guys are stand up boat folks and can offer you many options.

I built up a pair of 500EFI's last winter.....DON'T DO IT. Although we made alot of power and they sound great, I'll never do it again (fully dressed at 630 HP, 700TQ). It would have been alot cheaper to run the engines at 4,500 rpms all the time and re-build them (back to stock condition) after 200 hrs use.

Does the plenum need to be matched with the throttlebody?

Thats pretty impressive 630 hp!! I guess a long trip without refueling was out of the question?

If you put a bigger thottlebody like the 525 Yes you need to open up the stock manifold or you will still be restricted.

We put a Crane 741 series cam in one, reprogrammed the ECU, and did some mild port work on the heads and it made 563 hp. Also added the AZSM throttle body. The motor had valve train issue and had to be refreshened anyways, it wasn't opened up just to make more hp.

Could you give me some prices on a ECU reflash and 2000 cfm throttlebody. Arizona Speed and Marine has a 1300 cfm throttlebody for the 500 but I think yours will hve more airflow

be fair though Russ you made 540's out of yours and went through everything, he is asking about smaller things that can be done and they are plenty. comp changes, throttle bodys are the main, you can change cam and mill the heads for more. mine were 575 hp and not that expensive to do.

I bet that cam sounds BADDASS!!!

i ahve a 525 cam in mine and they sound great, idle like a dream and do what ever I want. they still arent the fastest, but this year I'm going alum heads and am shooting for 625. Mark and tyler know fuel injection like no one else...check with them and weigh out your options....you wont be dissapointed.

This boat runs approximately 75 mph! I would like to do at least 80 MPH! I know,I know the Baja's are so heavy and they have no steps. I think HP is my only option!

Thanks you have been a big help! What have you done to your motor besides your cam and what kind of boat are you running?

I did the same thing I used the 741 but put a pair of Dart 310 heads out of the box No cnc porting and made 587 HP with the bigger throttlebody. Then I put a set of fully cnc ported 315 AFR heads on and only gained 15 HP. Then I thought the intake and throttle body was holding me back so I put a Holley Intake on and a 2000 cfm throttlebody on and gained almost 40 HP but lost a lot of torque. Then I put the 500 efi manifold back on and cut a 4" by 4" hole in the top of the stock plenum and mounted the 2000 cfm throttlebody on and gained the same 40 HP and gained all the torque back plus some. That's why I made the new tops to go on the 500 and 525 engines when camshafts and head work are done on these engines.

I have had the cam, switched to alum heads this year, and computer work. I went from 72 mph to 77 mph and with the head and mor comp work I am hoping to be at 80. I have a straight hull 2000 Cig Tiger with pumped up twin 500 efi's and bravo xr's. i have a 9800 lb pig and it moves great for 42 ft long.

thats good to kow, I am putting afr 315's on mine.

Thats pretty impressive for only having two 500's!

exactly, they are great motors, just need to find the right set up. Zul has 500 efi's doing 640+ hp, but it going through the whole motor. make it breathe and give it fuel, it will run.

Guys you have been a big help. Thanks again. Tyler if you dont mind Ill be in touch. Im interested in the reflash and the throttlebodies. Im signing off. Hope to see you guys at the Emerald Coast Run

I know, I was coming back to post the 540 info....but I still say run the hell out of stock 500's and re-build more often as necessary. :D

if you are in Al, go see mark at precision marine in Kenner LA, he did my comp and they rock..if not him tyler will hook ya up...

You can trade me for stock 500's if you dislike them so much. Your pain in was self inflicted in the builds

I'll admit that too. Look at my first post here (#12). I like the motors but for the money spentI wouldn't do it again.

We haven't seen much of you lately, call me sometime. How's the place at the river coming along?

Likewise, Mark's a great guy and is really sharp with EFI. Not discounting any of the aforementioned engine guys because they all have great reputations and are all very knowledgeable. Just suggesting Mark because of proximity.

Also, if you are in Montgomery, Ala. and you would rather have someone else handle the mods for you, talk to Steve at Cathouse Performance Marine in Prattville. Good friend of mine and takes much pride in his work. Small shop but good guy to deal with. He does a lot of work with Mark at Precision.

Good luck

40BADBOY, you won't see much gain unless you either open up the stock heads, or replace them. They are a big limiting factor on the HP500EFI's. I have done the larger throttle body, and ECm reprogram. Didn't gain schit. So, I finally just Whippled the b itch. I'm good now :-)

I had a friend rebuild his 500 (carb) . new cam, higher compression, but didn't touch the heads. He went up a 1/2 pitch in prop and gained, MAYBE, 2 mph. He's pissed. He didn't touch the heads.

i have the same motors with 250 hrs. is it worth doing the heads cam and throttle body with out doing the bottom right now and is the crane 168731 big enough to do the job.

Save your money.

What do you mean by that comment ????