nothing left need some suggestions.
 

00 42 tiger, fresh motors, 600 hp xrs and 26 p 4 blades.

While running everything stops at 5K, have checked the rev limiters, they are at 5800 am checking throttle stops today, the boat runs great but dont know why it hits the wall. I figured with the 26's I would be bumping the limiter but I'm way off. Will having too small of a prop do this?

Re: nothing left need some suggestions.
 

What is the speed at 5000 rpm and what is the gear ratio of the drives?

Matt

Re: nothing left need some suggestions.
 

speed is 69-70 and drives are 1.5's. Was running 73 last year and spinning at 5100-5200 with the same props, stock 26's..

Re: nothing left need some suggestions.
 

Something is not right and unless you have some obvious prop damage I don't think it's a prop issue.

Too small a prop will not cause the problem you have. I would go over the motors to figure out what's going on.

When you say the motors are fresh what was done to them? Was there a cam change, carb change, heads, etc. Something with the motors is different from last year. I would figure out what's going on with the motors. Do you have dyno sheets for these motors?

Matt

Re: nothing left need some suggestions.
 

the motors have gone up in hp, yes the cam was changed.the 500's now are making 580-600. comps have been redone. my motor builder and the guy that did the comp agree, I have to lab my 26's to get that rpm back. Was also told from a few sources that I may not see much of a top end improvement in a tiger. the stock 500 was in its power band at this speed, now my new ones don't make power until 5200-5500 so I will lab the 26 to get me there and then should find the extra mph, wether its 2 mph or 4 mph. either way I'm still pleased with the overall pkg, the midrange now is amazing.

Re: nothing left need some suggestions.
 

Have you added any weight to the boat?

Re: nothing left need some suggestions.
 

You may have to do some prop work to get the rpm up over a hump. Then the motors may make more power and bring the rpm where it needs to be.

If you can get your hands on some stock 24's that would be a good place to start. They should run close to the same rpm as lab finished 26's so they would give you a good idea of what the motors will do with a lower pitch prop or lab finishing.

If you can't find stock 24's to run we have them available in our test prop program.

Matt

Re: nothing left need some suggestions.
 

I agree to down pitch to see if the motors will pull past the 51-5200 range. If they only pull to 5300 with 24's, the power hasn't gone up in that range. It would be a natural progression meaning the power curve will not pull 26's beyond the normal Lab Finishing rpm gain of 5200-5300.

See if you can get a dyno reading done.

Re: nothing left need some suggestions.
 

Great talkin with you again yesterday Brett, props being labbed will test on Sat, let's hope our theory turns into a reality:)...Rob

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I have my 24's that you can try Rob

You have b1's or XR'S ??

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thanks,I have xr's just got the labbed back will try them today on my way to cambridge, they have the steel insert, does that make the b1's fix xr shafts?

Re: nothing left need some suggestions.
 

you are up in horsepower.........could you be down in torque?

Re: nothing left need some suggestions.
 

no the torque is well into the 620's... I did run with the labbed 26's and it seemed better, didnt get a chance to air it out and really test the intervals. have to align the throttles to have the motors running the same rpm. port side is 400 revs more at the same position. Once I get these little things straight I can get more accurate numbers. I may try some box 24's as well...It just freaks me out to make more hp and have to run smaller props, this boating thing is crazy..:D

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THAT Happen to me made more hp hit a wall put on a nickerson carb and a 2'' shortie hitting 5600 to 5800rpms with lab 26 was hitting 5100 74 before. old carb jetting was way off looked good on the dyno 647hp tq was 627. will re dyno this winter with new carb and head work.

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update:
Thanks to Brett at BBlades we have it figured out, tried some 24 stock and the RPMS flew to 5700 and the boat peaked at 73-74. It was hard to tell as it was kind of rough out. I am shickled titless at what JC did with my motors, hearing those things at 5700 is amazing, I have to get used to it. I'm going to have Brett do my 26 lab work and it should still be at 5700, I will also get a set of 24's to have as spares. Bretts calculations have the boat at 76.5, I'm hoping he is correct.

Oh btw, i had a local company depitch and "lab" my 26's, and it was 500 bucks wasted, I'm not mad, but next time I'll send it out and make sure it is done right by people that are experianced in hi perf apps.

I highly recommend Brett and his test program!!! thanks again for all your help, talk with you soon...Rob

Re: nothing left need some suggestions.
 

Who did the work locally Rob?? I wasn't aware anyone is "labbing" here.

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Millers Island, when they came back they were stamped 25, so I guess thier idea was to depitch them. I heard when the driver dropped them back off that he told the guys at the shop they will never do that again. I wish they would have just said, "no we dont do that type of work" Oh well it's only money huh?

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Hmmm, 25 huh? That might work for a certain Formula I know :cool:

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I have xr's we can get the hub adapter and try em out, call me and let me know, I'll be out next weekend:)..will be in vegas tues thru fri.

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I had props repaired by them. Had to send them to Throttle Up to have fixed, but Matt did a great job. Good props only go to Florida for us now.