500 hp
 

Well its been a long winter but the shop called Friday and was ready to to dyno my motor. I had this thing completely gone over cleaned and magna. The motor is a 500 hp carbed

I ended up going with 741 cam and Brodix BB2+ heads with a blower shop 250 blower. when i went down to the shop my camera battery was dead so i will put some pictures of the motor this week. I did take a picture of my dyno sheet so i will post that.

Let me know what you guys think and i could use some advice on a prop size.

The boat is 25 outlaw 1998. Thanks to everyone that helped out with advice.

http://i41.tinypic.com/20889d5.jpg

Great power. You will need a stout lower unit to handle that. I am no expert, but the air fuel ratio looks a little lean, especially at the top. May want to inquire further on that.

You should be spinning that combo to at least 5500rpms. Did you go any higher on the rpms????

Do you have the printout that shows the atmospheric data and the correction factor used to correct the uncorrected torque and hp to the corrected values? That info would be helpful.

No we didnt go any higher griff i was planning on 5200.

I will see if i can get that data thundersuck.

Way lean.

Ditto.

Although Al Gore and his friends might not think so ;)

So what should it be. The guy at the shop is saying its fine.

12.0 to 12.5 a/f

I just found out that the shop did not use my index regulator when they had it on the dyno would this have caused the problem.

I have no clue and this is why i paid these guys to set it up. So please i am open to any and all advice. Thanks

A 741 cam is going to keep making more horsepower up to at least 5500 rpms.

Like was said, way lean on the AF for a boat. For a drag car, it would be fine, but sustained rpms in boat are going to melt something and cause detonation.

So will the index regulator help with the problem or what should i have them do?

Also will the bottom end handle the 5500? All stock parts out of the 500. Merc says 5250. Thanks Griff

I agree, it needs to be revved higher. With those heads and that cam and a supercharger, it won't peak until it starts to float the valves. Probably around 6000 rpm. Looks like you have about 800 hp up there. Congrats. Way too lean. Like the other guys say. With the wrong AF ratio, you can put holes in the tops of your pistons the first time you try full throttle. Not a good way to start the season.

What do you mean index regulator? With a roots blower there is no need to index the fuel pressure regulator. Just make sure you have @ 7 lbs at all times. Boost referencing the power valves is something you might want to have done. Larger main jets on the secondary side about 4 sizes to start also.

One last thing, is your oil cooling system up to the task of removing all of this extra heat? If it's not, one minute of full throttle will put your oil temp at 300 degrees and weld bearings to crankshaft. Until you get to know this engine, keep a close eye on your oil temp gauge. When it hits 280, back off. I guess the reason I'm worried is because running lean causes high oil temp as the heat is passed thru the top of the piston. If your oil cooling system is marginal, running lean makes it worse.

Excellent advice PatriYacht.

Thanks, Niceguy

Definitely get the A/F right in the boat! Oil temp gauge and sufficient coolers also a must. Every one here giving advice learned it the hard way. Take a chance and you will too! By the way it cost me an engine for each one of my suggestions!!!

I don't know what you are referring to as the "index regulator"

The bottom end will handle 5500-5800rpms just fine. I spun my 454mag with an upgraded cam to 5500rpms.

The bottom end is fine to 6000 rpm. The weak link in any BBC is the valvetrain. That being said, without a cool, clean, unfoamed supply of oil at @ 60 lbs. it will have a short life.

Get it Right Now before you Loose it!
 

Looks like from these numbers you've got a nice combination in the engine and I think a 800HP @5500 sounds about right. Now to make it last and keep it reliable and safe!
I totally agree with PatriYacht and others here, the air fuels are way to lean if they are being measured correctly and this is where the actual setup and correction needs to be done on the dyno now or in the boat with a wideband to make sure the air fuels stay in a good range or you will burn that nice motor down in a heartbeat!!
The suggestions for a thermostatically controlled larger oil cooler on the engine and sufficient oil pan and oil capacity are also a MUST! The guys are right that this engine will produce peak power at about 5400-5500rpms with that cam and blower combo and you should set the rev -limiter arount 5600 unless you got some special valve train and you might want to prop for about 5500 rpm. Just some thoughts here.

Best Regards,
Ray @ Raylar

I have the stock oil cooler. Do you guys have any suggestions on a after market one or will it be ok?

The jets are 90 the guy took the motor off the dyno. He says its fine i trust what you guys are telling me but now i have no idea how to get it right.

So should i not run the index reg? I thought it was just added security. I forgot to mention that i also have the timing set at 28.

My last question is when this all started i was told my final comp would be 11 to 1 now i am told that its 13 to 1

So as far as fuel what should i run i was thinking turbo blue 110 mixed 50 50 with 93 will this be ok or is there a better route to go?

I would like to thank all that is helping me out i am so glad there is a good community at OSO that i can turn to for help and advice!!!! Thanks Jeramy

Timing is a little low at 28. Most guys are using about 30. Too low and you roast your exhaust valves, too high and you have detonation. I'm still not sure what you mean by index reg. Can you give a specific model or manufacturer name or picture? Sounds like a good mix of fuel but I would need to know what your compression ratio is and how many lbs of boost you are running. Are you using an intercooler? If you don't want to modify the carbs yourself send them to a good guy like Nickerson. Oh and a good size oil cooler is the 3x 18 from Eddie Marine.

The regulator i was told is a boost reference regulator that will pump 1 lb of fuel for every pound of boost it senses. Witch i am told is gonna lower my AF ratio. The static comp is 9.1 with 8.2 pounds of boost final comp is gonna be 13 to 13.7 is what i was told. I have consider going witha larger pulley on top witch would put me at around 7 lbs of boost at a final comp of around 12.7 again this is what i was told.

What should i run for fuel? also would i benefit from adding a thru hall water pick up?

Get a pulley to reduce the boost to below 6# and run pump fuel and spin it up to about 5600rpms. Keep the smaller pulley and get a second prop for when you want to run race fuel.

My pulley choices are are 3.35 witch should put me at 7 lbs then it goes to 3.60 witch is 5.2 lbs of boost.

I am worried about loosing a lot of power going to the 3.60 pulley.

If the motor can handle the 7 lb or the 8.2 lb on race fuel thats the rout e i will go i have a friend i can get it from that its only a 1.00 a gallon more than 93. What do you guys think?

If you don't mind the hassel go ahead and run the race fuel and high boost. It should be ok but problems always happen faster and more severe at higher boost. From the sound of it you are going to need help tuning this engine. Where are you located? Maybe we can help you find someone. Btw, a boost referenced fuel pressure regulator is for blow thru the carb applications like Procharger or turbocharged not roots type blowers. A Bravo water pickup can move a lot of water so it should be ok. Maybe change to a cooler thermostat. Arizona Speed and Marine has a 120 degree thermstat.

I live by peoria I'll
I just thought I would lose a lot of power going to the 5
Lb and with seven lb I Would need to run race gas. I will go with what you guys recomend .

There is a guy in West Michigan, Dave Wessledyke, I think his company is called Wesco, who is one of the best at building and tuning marine engines. I know 10x here on the board went to him for his most recent set of engines. The more I think about it, you need to get away from the guys that set up your engine. 9.1 compression, 8.2 lbs of boost, no intercooler and lean fuel mixture is an engine failure waiting to happen. It can be tuned to run on a mixture of race gas and premium but your margin for error will be small. Take it to someone who really knows what they are doing.

You should still make at least 700hp running 5.2# of boost. Your drive will be happier as well.

I think he has air/ fuel ratio confused with compression ratio, both need to be lowered. And how does fuel pressue change fuel mixtue on a carb motor ?

Did u upgrade the motor mounts? Someone told me Baja lags into the stringers instead of using the offshore type. Like I said, that's what I heard

BTW, congrats on the power increase. I'm thinking about doing the same to my 500's if I keep my boat. 3 blowers:eek:

I talked with the motor guy again. He said he told me that the AF was 1 point off when he checks it with a O2 sensor. So he said i will have to take 1 point off the totals. He also said that he was gonna re jet the carb.

The carb has 90,s front and back. he said that he was putting 93,s in the front and 95,s in the back.

my 93 outlaw is just lagged. i did not switch to offshore mounts but i installed metal plates across the stringers to help distribute the weight. then re-alined the engine. it is that same baja style.... cheap and quick. might be my last baja

What size & brand carb are you working with ?

1050 dominator

You may be able to reduce high speed air bleed size so you won,t have to run such a big main jet, big jets will foul plugs in lower RPM range.

I would put the power valves back in the carbs & run 86-88 jets. Big carb with rich jets = ring & bearing failure.

Exactly, unless it was loosing or had low fuel pressure at higher rpms, it doesn't do anything to richen it.