Good, honest advice wanted.
11-05-2002, 11:45 AM
#41
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Joey,
Here`s the boat: Baja Hammer, 21`8", 3600#. Stock configuration: 7.4 MPI thru-hull exh with stock manifolds/risers. GPS 67.1 @ 4650 rpm.
Installed Stainless Marine GEN III manifolds and tailpipes, K&N arrestor, Vortec adj fuel reg set @ 43 psi WOT. Results: GPS 67.3 @4650 rpm (hits rev-limiter at 4700). Running a 23" Mirage Plus (blueprinted).
It does FEEL like it pulls harder through mid-range, but seems to taper off around 4000 rpm. Several people have suggested the MPI is the bottleneck, hence the carb swap. I just thought while I had the intake off I would swap to a more efficient camshaft. I would really like to see this hit 70 on GPS.
Here`s the boat: Baja Hammer, 21`8", 3600#. Stock configuration: 7.4 MPI thru-hull exh with stock manifolds/risers. GPS 67.1 @ 4650 rpm.
Installed Stainless Marine GEN III manifolds and tailpipes, K&N arrestor, Vortec adj fuel reg set @ 43 psi WOT. Results: GPS 67.3 @4650 rpm (hits rev-limiter at 4700). Running a 23" Mirage Plus (blueprinted).
It does FEEL like it pulls harder through mid-range, but seems to taper off around 4000 rpm. Several people have suggested the MPI is the bottleneck, hence the carb swap. I just thought while I had the intake off I would swap to a more efficient camshaft. I would really like to see this hit 70 on GPS.
11-05-2002, 12:12 PM
#42
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http://www.boatramp.com/prop_applet/...erAppletG.html
run the #'s and see what you come up with.
i have re-worked and mod'ed a lot of efi engines...have even gone so far as to redesign the throttle body for one (flow was tremendous but gains were nothing on top). i have no idea what efi system is on that engine (year?)....
70 is a good goal to have....but that's a big # for that prop and RPM...like i said you do the #'s....first thing you have to do is the math...then base line...you gota find out what the hell prop is now on there?...what drive do you have?? pick ups?? check the mph with another gps (or two)....LEAVE the efi on there for now while doing all this....if 67 is not an erroneous number then 70 should go....trust me...don't bail out on your setup yet...
i think wett vett has this hull??...get some #'s from him....inquire about X dim. as well.
what you need is data from people with the same hull, X, and drive (get the SN) as yours....the engine means NOTHING right now...get what props they have used and are using and what RPMS...then with the link i provided plug all the numers. ....so get to it...start a new thread...."what are your #'s (prop/RPM/speed)for your hammer?"...get a little data base and see what you have to do and what your up against??
run the #'s and see what you come up with.
i have re-worked and mod'ed a lot of efi engines...have even gone so far as to redesign the throttle body for one (flow was tremendous but gains were nothing on top). i have no idea what efi system is on that engine (year?)....
70 is a good goal to have....but that's a big # for that prop and RPM...like i said you do the #'s....first thing you have to do is the math...then base line...you gota find out what the hell prop is now on there?...what drive do you have?? pick ups?? check the mph with another gps (or two)....LEAVE the efi on there for now while doing all this....if 67 is not an erroneous number then 70 should go....trust me...don't bail out on your setup yet...
i think wett vett has this hull??...get some #'s from him....inquire about X dim. as well.
what you need is data from people with the same hull, X, and drive (get the SN) as yours....the engine means NOTHING right now...get what props they have used and are using and what RPMS...then with the link i provided plug all the numers. ....so get to it...start a new thread...."what are your #'s (prop/RPM/speed)for your hammer?"...get a little data base and see what you have to do and what your up against??
11-05-2002, 02:17 PM
#43
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Don't forget to see if your boat responds to more fresh air in the engine compartment. There are several here with Bajas that responded with 100 more rpm when cracking the hatch. I think that's crappy design on Baja's part, but if it's there, take it and smile.
If you run your numbers, they come out to a very low slip (too low). That blueprinted prop must have some more pitch or cup, or your tach may be a little off. Still looks like it's in a good direction.
Have you considered the Crane 226/236 587/610-112 roller cam? It works real good in applications like yours. I also would not be too scared of running that motor to 5500rpm. I did it for three seasons and never heard a peep. Engine looked new upon dissassembly. Maybe I was lucky, but I think these engines can take more than many think, as long as you don't get ludicrous. I think it would be leaving too much on the table to run either cam below 5000 rpm, 5200 better.
I think Wette's hull is a little different than yours, but close enough for some comparison. I think he had good luck with a shorty drive.
I would stay with the TB distributor and ignition, you don't need any more. The straight hp module that was used on old hp 500 carb motors has a 20 degree advance with no internal limiter. Add an MSD limiter and your there.
If you run your numbers, they come out to a very low slip (too low). That blueprinted prop must have some more pitch or cup, or your tach may be a little off. Still looks like it's in a good direction.
Have you considered the Crane 226/236 587/610-112 roller cam? It works real good in applications like yours. I also would not be too scared of running that motor to 5500rpm. I did it for three seasons and never heard a peep. Engine looked new upon dissassembly. Maybe I was lucky, but I think these engines can take more than many think, as long as you don't get ludicrous. I think it would be leaving too much on the table to run either cam below 5000 rpm, 5200 better.
I think Wette's hull is a little different than yours, but close enough for some comparison. I think he had good luck with a shorty drive.
I would stay with the TB distributor and ignition, you don't need any more. The straight hp module that was used on old hp 500 carb motors has a 20 degree advance with no internal limiter. Add an MSD limiter and your there.
11-05-2002, 02:26 PM
#44
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Good point about the steering. You need to check the current state of your gimbal ring. I was once talking to Gene Weeks about my hull and when he heard that I didn't have hydraulic steering and was doing ~85 in that boat, he almost hung up on me. I didn't understand until the horror stories I heard from members here drove it home. It's something you need to seriously consider if you plan on keeping the boat a while and like driving fast.
WPM sells full hydraulic systems for a good price. I couldn't be happier with mine.
Good luck!
WPM sells full hydraulic systems for a good price. I couldn't be happier with mine.
Good luck!
11-05-2002, 02:42 PM
#45
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My hull is an older 210 Sport, which is similar to the Hammer. If you are running 67 and hitting the rev limiter you are an easy 70 with the correct prop. Call Hydromotive and run the numbers by them. They will recommend a prop and if it doesn't work you can return it for $50.00 restock or try a different for $20.00. It is a pretty good deal and they did a great job helping me find a spare prop to my custom Spinelli. If 70 is REALLY what you want to see I would say leave it as is and do some prop testing first. The short drive works well on my boat. without it driveability at 75 MPH plus was difficult. My boat is a 1990 and you have to keep in mind that 4 blade props were just gaining popularity and x dims were much less aggressive to accomodate the standard 3 blade wheels. Newer models have higher x dims and may not like the 2.5" shorty. It costs $2500.00 to find out unless you have a good buddy that is willing to let you try it. If you are interested I know a guy that has an IMCO shorty for sale because it didn't work on his boat. (bottom only)
11-05-2002, 02:53 PM
#46
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My .02 is to only change from the EFI to a carb as a last resort. You will be trashing the value of the boat/engine by taking the stock EFI off. I would explore what your options are to modify that injection system. You can make the cast iron version of the 454 run pretty good, even with the cast parts, but it takes more than just adding the a bigger cam and carb. As Dyno said, if you are going to spin these cast motors up, your machine work and assembly must be top notch. Also, 67.3 MPH@ 4,650 RPM with a 23 inch pitch is pretty damn good, almost to good.
Enjoy what you have and build yourself another engine on the side in your spare time. Like you said, do it right the first time!
Enjoy what you have and build yourself another engine on the side in your spare time. Like you said, do it right the first time!
11-05-2002, 03:24 PM
#47
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Several good points here guys. Thank You.
Joey, I think I am finally understanding where you`re coming from. You just didn`t have a good presentation at first. I will run my numbers, see what gives. This GPS I was using may be optimistic, if that`s possible. I borrowed it from a buddy and it is several years old. My tach could very well be off too. A while back, I ran some numbers from the BAM Marine site. If memory serves me, it said something like 65 mph with my prop and RPM with average slip%. I am beginning to have my doubts about my true top speed. My Farria speed shows 68...
I have considered building another engine in my spare time, but you know, Joey may ACTUALLY be making some sense
I should optimize my hull and wring all I can out of it first, then look towards engine mods if still not happy.
Keep the opinions coming, I am stewing all this info right now.
THANKS!
Joey, I think I am finally understanding where you`re coming from. You just didn`t have a good presentation at first. I will run my numbers, see what gives. This GPS I was using may be optimistic, if that`s possible. I borrowed it from a buddy and it is several years old. My tach could very well be off too. A while back, I ran some numbers from the BAM Marine site. If memory serves me, it said something like 65 mph with my prop and RPM with average slip%. I am beginning to have my doubts about my true top speed. My Farria speed shows 68...
I have considered building another engine in my spare time, but you know, Joey may ACTUALLY be making some sense
I should optimize my hull and wring all I can out of it first, then look towards engine mods if still not happy.Keep the opinions coming, I am stewing all this info right now.
THANKS!
11-05-2002, 03:39 PM
#48
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I plugged in the numbers abd something`s not jiving
It first said that run the numbers I think I`m running, I have only 2% prop slip...not likely.
If I plug in like 8% slip, it says 65 mph.
As per Joey`s advice I am going to start a new thread here asking for info from Hammer owners.
Thanks!!!!
It first said that run the numbers I think I`m running, I have only 2% prop slip...not likely.
If I plug in like 8% slip, it says 65 mph.
As per Joey`s advice I am going to start a new thread here asking for info from Hammer owners.
Thanks!!!!
11-05-2002, 04:47 PM
#49
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Hey Wette, could you give us your measurement (cord style) from the bottom of the transom assembly to the pad bottom of the boat? Cord says to add 9.25 to get a handle on what the actual crank to prop distance is. I hate trying to measure the actual prop to bottom of boat on the trailer. Then I guess you would subtract 2.5" from that for apples to apples for a standard B1.
11-05-2002, 05:08 PM
#50
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No prob Brad. I will do that this coming weekend. I have the boat in mothballs until spring, but this will give me an excuse to check on it. I will take a few different measurements and let you know.
