Whiplash Gen II Sport X with a CMB101

[RaceMechaniX]

YEs I did have a chance to run it. Ended up running a 91rs instead of the 101 due to some problems with the 101. Ran a AB billet 101 pipe at 12.5" on 45%. Tested about a dozen different props and similar gas props ran the best. We ended up running a Brent Dailey 6719/3 progressive pitch 35/45/55 prop. Speed was a consistent 72mph in flat water running a little rich. Leaning it down produced speeds up to 75, but the motor was coming back too warm. My GX-1 whip runs a consistent 74-76mph with the same prop. The nitro version starts heavier tha the gas version with the extra weight of the fuel, but burns it off quickly. I would say either setup is very cometitive. Don't know if the backlash will run the same. There is more performce to be had, but the set-up runs consistently and pulls from a medium slow mill start pretty good.

The CMB Alpha is a potent engine and at least in the rigger I have seen it run in there was no performance disadvantage from the extra weight.

Tyler

 

[Ross Petersen]

Thanks for the test results,I think I'm better off keeping with the gas engine in the backlash being bigger and heaver than the wip.

I might still give it a run as I have most of the set up completed accept for cutting the cowl ,past the point of no return.I'll just make some sort of temp cowl.

Like you mentioned fuel storage could be a problem without major mods to boat,different project maybe,just liked the idea of trying the nitro engine in it.

Good luck with your future testing .

Thanks.

Ross

 

[RaceMechaniX]

Ross, I would say so. The weight of the fuel is not a huge penalty, but it takes careful placement. I had fuel draw issues running two tanks with the second one behind the engine. I ended up removing the second tank for testing and just had to refill often. I bought a smaller second tank yesterday to move under the starboard side deck adjacent to the engine. I do like the nitro variant of the whip and with the CMB it starts and runs in competitive trim. I have a district race in the August and plan on running it in open oval.

 

[Ross Petersen]

A couple of photos of the mounts I milled up to fit onto original Backlash mounting rubbers,I.m just going to leave tank in front for trial as I will set boat up back to rcmk motor. I will try with Cmb 101, this is 90 out of other boat just for fit up.

 

[RaceMechaniX]

Nice mount design Ross. I had drawn up a set just like those but ran out of time to machine a pair. Tyler

 

[julianconde]

Tyler put the 1394 pipe at 11 1/2 that's what we run in F Mono, F Hydro and Twin hydro with the 91RS or 101 RS. Also try running some MC9 or OD89 plugs they will do great as well. Pull some of the element out too run 60% nitro ;-)

This is a very nice project I like it if you can post some videos.

 

[RaceMechaniX]

Julian, I tried the 1394 pipe short like it is in my SD3, but it would not pull it. Element was pulled, but just running 45% with a ton of oil. We put small props on, but it was not happy. I have a district race this weekend where it's entered in open oval. I'll report after the race. TG

 

[julianconde]

Julian, I tried the 1394 pipe short like it is in my SD3, but it would not pull it. Element was pulled, but just running 45% with a ton of oil. We put small props on, but it was not happy. I have a district race this weekend where it's entered in open oval. I'll report after the race. TG

Wow that's interesting. I use the 1394 for every big block I have with very good results on the mono and Twin. We run 60% nitro and 18% oil with 3oz of Klotz kl100 to each gallon. What issues did you have with your 101RS ? Post some videos it would be interesting to see.

Julian

 

[RaceMechaniX]

At the district race this weekend I finally was able to test the Sport X in race water with mixed results. First off the boat is fast, very fast as in somewhere between 72 and 75 mph. It picked up speed as it got chopped up just like the GX-1 sport hydro I have. However, in two heats it hit rollers and just went sailing. In the last heat, I stuck a buoy dead on the right sponson. At partial to 3/4 throttle that boat looks sticky on the front end, but at full song it looks pretty good. Still some refinement needed to trim the boat and I need a strong turnfin bracket. In the race I did finish I think I lapped most of the field although I don't think the faster boats were on their A game for that heat. The whiplash turns and tracks like a rigger, so pretty pleased with the results. Julian, I think difference is in the wetted surface area when the boat is off plane. The Whip has a lot of drag milling around compared to a rigger so it needs the extra low end grunt to get it back up. I found no advantage to running 60% over 45% and we are running a little more than 20% oil with some of it Castor. Seems to seal up and lubricate better than pure Klotz. The sleeve looks great with the new blend. There were some people snapping pics and video at the race so if they got some footage I will post them. TG

 

[julianconde]

At the district race this weekend I finally was able to test the Sport X in race water with mixed results. First off the boat is fast, very fast as in somewhere between 72 and 75 mph. It picked up speed as it got chopped up just like the GX-1 sport hydro I have. However, in two heats it hit rollers and just went sailing. In the last heat, I stuck a buoy dead on the right sponson. At partial to 3/4 throttle that boat looks sticky on the front end, but at full song it looks pretty good. Still some refinement needed to trim the boat and I need a strong turnfin bracket. In the race I did finish I think I lapped most of the field although I don't think the faster boats were on their A game for that heat. The whiplash turns and tracks like a rigger, so pretty pleased with the results. Julian, I think difference is in the wetted surface area when the boat is off plane. The Whip has a lot of drag milling around compared to a rigger so it needs the extra low end grunt to get it back up. I found no advantage to running 60% over 45% and we are running a little more than 20% oil with some of it Castor. Seems to seal up and lubricate better than pure Klotz. The sleeve looks great with the new blend. There were some people snapping pics and video at the race so if they got some footage I will post them. TG

Tyler that's good guess it hauls the mail fine tune it and go for it again. I do agree with you a sport hydro does have more wet surfaces then a rigger. So your saying there no advantage at all from running 45% to 60 % that's interesting. I use technology hobbies fuel what ever he puts on it 18% oil then I add 3oz of Klotz KL100 per gallon. after a year and some change the engine on the inside looks brand new and has a perfect seal ;-) but what works for one person does not work for everyone.

I would love to see videos of the boat running.

Julian Conde

 

[RaceMechaniX]

Julian, at least for the bowl/squish combo I am running the 45% is easier to needle and still has plenty of performance. Granted I am not trying to squeeze every last bit of performance from this particular motor. Just something to run in open and keep the motor solid. The 91VAC I run in my SGX runs 60% with the Mac pipe and it is quite happy. We'll see if any pics or vids pop up from Vance who was filming at the race. TG