Blower Upgrade
 

The boat is a 2000 Checkmate 259 Convincor we bought new in 2002. The original power was a 454MAG(MPI) in front of a Bravo Drive w/ a Mirage Plus 23 pitch prop. The boat currently has 265 hours on it. At 215 hours we upgraded the motor with a Stainless Marine exhaust system, roller cam, 2.25 intake valves, 1.89 Inconel exhaust valves, new valve springs, locks and seals, milled the heads .020, roller rocker arms, rocker studs, pushrods, valve job and changed the prop to a 26 Bravo labbed. The engine was dynoed at 461HP (5100RPMs) and 514lbs/tq (3800RPMs). The upgraded motor has 50 hours on it. The engine was upgraded by Tyler Crockett and runs great. The boat also has full hydraulic steering and HP trim tabs. I feel the boat can handle more power. I am thinking about installing a Blowershop 250 blower w/ a single 1050 blower carb 5lbs boost, an oil cooler and a MSD ignition. The combo should make around 600HP. I have always wanted a roots style blower. The valve train only has 50 hours on it. The boat is used for all purpose recreational boating. It needs to idle well, start consistenly and run well in most conditions. I am expecting 200 hours out of this engine and drive with this upgrade. Is this upgrade and expectation reasonable with this setup? Is changing the fuel injection to a carb setup crazy? Anything I am missing. Any thoughts and/or opinions would be appreciated.

Sounds reasonable to me. Have Nickerson set up the carb and it should idle just fine.

My 525sc with a 1050cfm idled like an EFI after it was warmed up. They are a little cold blooded at initial start up.

The drive may or may not handle it for that long. It depends on how good of condition its in now and how you treat it.

Thanks for sharing your experience Griff.

That sounds very close to the exact same power/torque and RPM's my cousin Jason's 454's make! Only he's running some real old GM semi open chamber truck heads (large oval port runners) and upgraded to larger valves (2.19"/1.85"), dual plane intakes, heads were pocket/bowl ported by JimV and cylinder bores had a "bore notch" job done to them, 8.6 comp ratio, stock Merc Thunderbolt ignition, cams are Comp Cams flat tapper hydraulic 218*/226* .515"/.515" on 110* lobes......made 461hp @5100rpm and 510 or 514lbs or torque @3600 or 3800rpm on Tom Earhart's dyno with tubular car/dyno headers. Jason runs GIL dry exhaust in the boat.

I think he made good power mostly from JimV's head port work and the bore notch job JimV did as well.

Would you have any concerns running 5 pounds of boost, no intercooler on with this engine with the current compression? I think the compression should be around 9:1, not sure.

Yeah I think the power is good for the displacement and head work. My problem is I can not keep up with the twin engine boats on our local lake. Everyone is always waiting on the Checkmate at the stops. I think 5 pounds of boost will help me keep up with the herd.

I think you won't need the 1050 carb, a 850 will work fine, a weiand 177 will work very well as well on that size engine, I'm running a 251 with a 489 w/850. you might consider H2O injection to help prevent det. be sure fuel delivery is good, the mallory dist will work better as you can dial in the total amount of advance, restricted on the msd with their bushings. you want about 15-18 degree's of initial and about 28 total, your H/P #'s should be close, but pay attention to your cam, a blower profile will help, mine is a comp on a 114 center...hope this helps, Rob

Tyler Crockett recommended the 250 and 1050 carb. Predetonation is a big concern. I am not familar with H20 injection. Would that be needed with 5 pounds of boost? Should I consider less boost? The blower upgrade kit would include an adjustable fuel regulator, blower, carb, oil cooler, fuel pump, fuel line and throttle bracket, billet flame arrestor and MSD ignition. Anything else needed?

I had a cig. top gun, with 525SC's upgraded with blower shop 250's and 1050 dominators. The setup ran great. I would check cam profile, should have lobe centerline of 112 or 114. good luck

How many hours did you put on the motors with this setup? Thanks for the cam profile info, I will look into it.

about 150hrs. never skipped a beat

You don't need water injection with 5# of boost. Your static comp ratio is about 8.9:1. Keep the boost at 4-5# and it should be fine on 93 octane.
I would also go with a 250 blower over the 177 if you are buying something. The 250 will make less heat and reduce the risk of detonation. Have Nickerson set up a carb for you.

Griff,
How about retarding the timing to 18 degrees total advance and running on 91 octane? Is that possible with this setup? What are the trade offs of retarding the timing to prevent detonation on lower octane fuels? Tyler will sell me a blower prepped 1050 carb, I will ask him if it is from Nickerson.

Sounds like I need to buy the blower kit.

Total agreement here. 575sci has a 256 stock, an 871 would have been a better fit with its 7.5:1 low compression. With your higher compression the 256 should be fine. As someone else also mentioned you will most likely want another cam for a supercharged application. I am sure Crocket would have a few grinds in mind. Keep in mind your hatch clearance. If it does not clear do you really wanna cut it? Are you sure you want to loose the FI?

If it were me...I think I might just trade up for more power...most of the time its cheaper.

18*?????????? is not even close to enough timing.

28-30* is probably the minimum total timing you want to run. If you only have 91 octane available, then I would try to keep boost around 4#. TC should have a good idea of what you need for the carb and it should work fine.

Here's some good reading from the Holley web site
http://www.holley.com/data/TechServi...ech%20Info.pdf

How to get to 600HP on a budget is a major influence in the decision to supercharge. Supercharging what we have seems to be significantly less money than building a large displacement NA from scratch.

Griff,
Thanks for the technical info on superchargers, very informative.

Hey Rob,

Cant say I can help with anything about superchargers. I have very little experience with them. I can say this... Do you think you have enough room in front of your crank for that big wide blower pulley? Mine is the same boat as yours and mine wold be real tight, if not impossible.

Good point Vinny. It appears some fabrication will be necessary. I think a little saw action and some rearrangement of a crossbracket for the seat will be needed. I think it can be done without too much hassle. Although these projects all seem easier to me because I watch someone else struggle through it.:grinser010:

Dont forget this.. the fuel tank is just in front of the crank. Cant move that too easily. I never measured it, but maybe you should have someone close you into the bilge and measure the clearance between the the hatch and the front of the engine. Do you think the pulley of a roots style charger would clear the hatch? Not concerned about the top, but the front is where it will get tight. For instance, my closed cooling tank comes real close to the hatch.

Vinny,
I just took some measurements. It appears the belt assembly is approximately 3 inches from the tank wall. The crank is above the wall but the water pump dips below the wall. I would assume everything attached to the serpentine belt gets moved forward. Is that correct? Maybe the blower will not work.
Rob

hey rob, every consider a whipple instead... you won't have near the height and I thought they were suppose to be easier to idle than the roots type blower .

Don

Anything less than 28* on your timing will work against you and create lots of heat into the exhaust. Good thing you have inconel exhausts..

As said, you're better to find a cam/boost combo that allows you to run the available fuel at effective timing numbers like 32*.

Accessory drives are available to get you functional at your current crank/fuel tank location. Also, your blower drive on a 250 is in FRONT of your existing accessory belting. Water pump should stay in normal position.

Water injection is great, but you don't see it very often. At low boost and moderate performance, you don't need it.

I'll take a 250 over a 177 any day. It's got extra reserves for when you decide to bolt it on a 502 (a 177 just ain't enough for much of a 502). It's easier to sell if you decide to do that.

Yeah, a 177 will have to work extra hard to get you where you are talking about going, but that's maxed out. You're already going to be above the thermal efficiency curve on it. At the same power levels, you will require higher octane fuel with the 177 than with the 250 due to the mechanical heat you're gonna whip into it. Also, with the additional heat from the 177, 5 pounds of boost will give less HP than 5 pounds from the 250.

If you're looking for 600 HP though, I honestly don't think 5 pounds of boost will get you there with your current setup.

You'll be needing to BORE NOTCH, and spin the motor closer to 5600.

1050 carb is a lot of carb for that motor, but it's very tunable and well suited to the application.

go get em.
mc

As I said, I have almost no experience with blowers. The most I have done with them, is take them off my friends 575SC's and send them to the blower shop for rebuild. If my memory is correct, on his 575's, the blower belt is the outer most belt, the accessories are in there stock location. Sounds like its going to be time to get out the butter to squeeze this engine in. :hitfan:

I think I am putting my supercharger pipedream on hold until our current motor tires out. Then we will either rebuild and supercharge or trade it in for natural big cubes.:party-smiley-004:

I run a similar setup with a ProCharger. I have aluminum Edelbrock heads and a more radical cam, also upgraded fuel system to include injectors.. With a 7lb pully made an easy 710 HP and 727 ft lb torque. Not a bad way to go. Tyler dynoed it talk to him.
Bob

Hey Don how are you? You make a good point. I like the old style theme for the Checkmate. A roots sytle carbed blower maybe less efficient and a little more likely to detonate but they look cool and our "cost effective"(at least upfront which is important for the marriage). Have you put many hours on the new power? Do you plan and pulling the AO to Clinton anytime soon? Hope all is well.
Rob

[QUOTE=RBeyer;2571545]I run a similar setup with a ProCharger. I have aluminum Edelbrock heads and a more radical cam, also upgraded fuel system to include injectors.. With a 7lb pully made an easy 710 HP and 727 ft lb torque. Not a bad way to go. Tyler dynoed it talk to him.
Bob[/QUOTE
What prop are running now with 700HP? We still use your old 24 Hydromotive.

Vinny, yes it can be done seen a couple done, I have pics showing what has to be cut behind the seat..but yes, very close for sure..there are 2 blown 251's running around me with big blowers, one ran well over 100 at the radar run a year ago...the other never straitened out but ran in the 90's, Rob