Sunsation Dominator 383 build project
 

Hey guys,

There has been a lot of talk about 6.2s lately and upgrades, so I figured I'd share some details about mine now that it is finally coming together. I've been working with Bob Lloyd at Full Throttle Marine and we're pretty excited to get this thing together.

My boat was originally with 6.2s and clogged injectors caused them to lean out then blow a chunk of piston loose. A big bummer, but I think this should be an exciting upside about having to do rebuilds. If you haven't had your injectors flow tested recently, you might want to think about it! Wish someone told me!

The builds:

Bored out to 383
Forged pistons
Custom cam from Bob Madera
Comp roller rockers
Edelbrock intake
Kept the Lunati crank
Getting rid of the captain's call and putting on
GLM Exhaust manifolds with stainless risers

The first engine is finished and on the dyno. Bob is going to save all the data and send the computer off for tuning tomorrow. So hopefully we'll know soon how much power we're going to get. Aiming for at least 400 and hopefully a good bit more.

Here's some pics and a vid:

http://www.austinboatforums.com/cgi-...num=1384826827

You'll get the 400+ ...no problem...but more importantly you'll get 450-500 # of torque!!

Why so lean? Sounds stupid to not fatten the entire curve initially so you don't hurt brand new motors.

Have to send off the computers to get that done which is getting done tomorrow.

I will be real interested in this. Can I ask why GLM manifolds?

That was just a bit of luck. I couldn't quite swing doing full headers and it turned out, the boat already had the GLM manifolds. They do flow better than stock, but more importantly the risk of reversion is much lower so we were able to go with a larger cam.

How much gain are you hoping to see in mph and are you upgrading props? I've got a $100 that says Ole 2 Buckets will walk that ass. :boat:

This is with the stock computer. It is the ECM555 that I cannot program. We are gathering data to send it to Mark Boos to reprogram. Yeh it's crazy lean. That is a good thing. It means we're flowing a lot more air than it did stock. Now we just need to get the fuel to it.

Not to derail but how easy is this to do to a 350 mag mpi with mefi3 computer. I assume whole new rotating assembly, what else?

I'm no bench racer, so when it's done I'll post whatever it does. No point in guessing. My goals were to build an extremely reliable engine with solid quality parts that would make quite a bit more power than stock. Not looking to be the fastest guy on the lake, just a faster guy on the lake. :) I was pretty happy with my performance before.

I don't think I heard how your new setup turned out. Pretty happy with it? I knew she flew before your did your rebuild so I'd imagine it's really good now.

I'm just pokin at ya, Evan. Nothing changed on my motor. Just did a valve job and made some improvements to the fuel system. Haven't run her much since then as I'm looking to sell when spring rolls around. However, she's back to her old self and pulling like a freight train.

https://www.youtube.com/watch?v=ey__...e_gdata_player

She's alive again! Lake test today.

Catpain Yarrr, How fast was your boat before? How fast is it now? What intake did you use? Did you stay with the stock throttle body?

The best I've ever seen was me, one other guy, cold day and light on fuel got 72. So that's optimal conditions. Under average conditions it was in the 68 range and sometimes 70.

We just got 74 at a lake higher altitude than I normally run, running rich so we've got some tuning to do before it's dialed in. Expecting another 2-3 MPH when we're all done. I'm sure I'll get faster on another "perfect conditions" day. But in terms of a real every day MPH that's where we are at. I probably should start looking at making some prop changes as well. I'll probably need to get down to the coast to hit my internet forum racing bragging MPH number :)

We used an Edelbrock 29135 intake. We still have the same throttle body. Bob Lloyd put on another bigger throttle body on the dyno and picked up 10 HP. I decided against putting a new throttle body on because it's a lot of money for a small gain.

do you know the specs on the cam? what intake are you using? do you know what throttle body he tried?

Intake is Edelbrock Super Victor EFI intake. Throttle body was a 1000 CFM 4bbl style EFI. It actually picked up closer to 15 HP. Really surprised me since the 6.2 throttle body is the same as run on the 496 and I've run them over 500 HP. Difference is the huge plenum on the 496. As far as other specs, I'll let Capt YARRR post them. I'ts his baby.

Bob

Bob ,, if i understand right you tried the throttle body as is with stock tune on ECM for the 6.2...... do you think you would get more HP/TQ out of it if ECM was tuned with the larger throttle body?

He tried it when the engine already had a few rounds of tuning and was pretty close.

I'll get some cam specs up tomorrow maybe.

Throttle body was after final tuning. Made a pull with stock TB, installed new TB and made another pull. All wihtin a 30 minute window of time. Stock made 399.9 HP @ 5400 RPM, 4 bbl made 415.3 @ 5600 RPM. Also peak HP moved up 200 RPM, so it definitely appears the stock TB is too small.

Bob, did you add oil coolers?

Please keep in mind these engines are being dyno'd in complete marine trim, running stock manifolds with full water.Just for grins I pulled the serpentine belt and made a pull without accessories. That brought it up over 425 HP. If you installed dyno headers you easily pick up 25-30 HP. So for comparison purposes with other custom builds and dyno tests these engines are well over 450 HP. Also, for real world comparison, a 496 HO makes 430 HP on my dyno in complete marine trim, 496 Mag makes around 390 and 502 Mag made 440.

Bob Lloyd
Full Throttle Marine

Yes, I installed some take off 454 oil coolers I had.

Catpain Yarrr ,, bob ,, were the heads stock cast or some port work done and are you running stock size valves? How did the tq look with the bigger throttle body ? Hey Captain Yarrr what prop are you running ?

I did a pretty thorough bowl blend but used stock valves. Throttle body picked up about 10 ft. lbs. across the board. When I get time I'll try to post the dyno sheets if it's OK with the Capt. One other note. This is a 9:1 compression engine so it can run on 87 octane. That was one of the build requirements.

Nice project! Which heads and valve size?

Jeff

Stock Vortec heads & valves. Machined them for comp 986 springs.

hey bob, can you share cam specs,,,,, just curious ,,,

That's a pretty good result. Where did the torque end up?

Jeff

Sure Bob, feel free to post the sheets. Hopefully they can help someone.

Cam:
112.2 LSA
5.3 valve overlap
225.6 intake duration
.540 lift

Exhaust
232.4 duration
.526 lift

We are talking about spinning the props inward. Anyone know how the Dominator hull behaves with that?

383 dyno sheets
 

383 dyno sheet with stock throttle body, second is with 4 bbl throttle body

Good Work! You'll be pullin' stumps out of the river with those numbers.

Do you have a picture of the throttle bodies?


Jeff

I haven't had a chance to drive it yet, very excited to feel how it accelerates. Those torque numbers are amazingly flat from the word GO. We're hoping for next week to be finished with tuning if the Texas weather wants to play ball. Maybe my boat wants to be my Valentine.

Bob and Captain, just a few more questions if you don't mind (BTW - best thread on the 6.2s since I have been a member - thanks to you both).

Why the Super Victor Intake? The suggested power range is listed as 3500-8000? This is not meant in ANY way as a criticism I'm just curious if there are other options.

Did you try the matching #3978 throttle body?

What horsepower was left "on the table" by keeping the compression ratio low enough for 87 fuel? How high can you go on compression and still run safely on pump premium?

What oil temps are you experiencing after a good run at WOT? Current r.p.m.s at WOT?

Thanks for your time in advance -:)

Main reason on the intake is availability. The Edelbrock and a similar Holley intake are the only performance intakes available for the EFI Vortec small block. Since this is MPI the air velocity issues are not as big an issue either. You also don't need low end torque much below 3500 in this style boat. It's got plenty of torque. Just because the intake says it will flow to 8000 RPM, Doesn't mean it won't make more power at 5000 RPM. We're just not utilyzing it full potential, so I do understand where your question arises. Comes down to dollars and cents. An intake like the scorpion uses would probably be the best set up if cost wasn't a consideration.

Another point of compression would be worth 15-20 HP and still run on 93 octane.

We did not try any other throttle bodies. That is just what I had on the shelf.

Haven't run it enough to check oil temps. It doesn't have temp gauges. Probably be a good idea to check them with a temp gun, but with the cold winter water temps it's not going to tell you a whole lot.

Bob

If we went balls out, new throttle bodies, high compression and headers (we went with stainless risers and GLM manifolds), we could be knocking around the 430 - 440 range easily. My wallet just couldn't open quite that wide. :) The nice thing about two of those things, I can always add those later if I get itchy.

What kind of speeds are you hoping for out of this setup?

Bob, what are your thoughts on the 7138 EFI intake pictured below on a 6.2? It has an available 90mm throttle body.
Sounds like you are getting 496HO performance with a lighter weight 6.2. Very impressive.
http://www.beautifulmauicondo.com/bo...es/EFI7138.jpg

Be fun to test that intake. I've not seen any numbers on it so I don't know.

Quick video running back to the marina:

https://www.youtube.com/watch?v=Iga-...e_gdata_player