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Hi all. I am looking for advice on where to look for a problem. I have a bike that has Stage 3 gears, EC Intercooler kit, Billet fuel rail and injectors as well as the AEM fuel pump upgrade and P16 filter. The bike is running E85 and goes well and makes good power up to around 12,000rpm, and then it noses over and starts to go down. It should power on until 13,500 i would have thought. We are just setting up currently and first time it has run and dyno tuning it currently.

What are peoples thoughts?

It seems to be nudging 30psi boost, so could it be an overboost protection of some sort? Reaching the limits of the supercharger etc? Who has a solution to this?

Have replaced plugs and narrowed the plug gap, but still the same.
 

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Hi all. I am looking for advice on where to look for a problem. I have a bike that has Stage 3 gears, EC Intercooler kit, Billet fuel rail and injectors as well as the AEM fuel pump upgrade and P16 filter. The bike is running E85 and goes well and makes good power up to around 12,000rpm, and then it noses over and starts to go down. It should power on until 13,500 i would have thought. We are just setting up currently and first time it has run and dyno tuning it currently.

What are peoples thoughts?

It seems to be nudging 30psi boost, so could it be an overboost protection of some sort? Reaching the limits of the supercharger etc? Who has a solution to this?

Have replaced plugs and narrowed the plug gap, but still the same.
Hey man,

Yes, I have seen this with a handful of bikes. Based on my observations, typically the power flattens after 12k for Stage 2 gears and around 13k for Stage 3 gears. In my case, I have been able to dial back any drops in power by advancing the ignition timing. Timing advance is safe now with the lower boost temps. Fueling alone won't get the power back. On my graph, I have the same peak horsepower as before but I make it 1000rpm sooner. Everywhere else in the graph (4000-11000rpm) I made about 10hp more on pump gas than the bike did on Race gas when it didn't have the EC. It's definitely a faster bike now even on the pump gas. I'm going to head back before the season starts with some race fuel to do a "like-for-like" dyno comparison. I expect a gain of about 15hp from 4-11k rpm with the same peak figure as before (approx 260-263rwhp).

I've spoken to Ben at length and there are possibly a few factors at play.
- Colder temps always produce lower PSI. So it's typical to lose a couple of PSI when intercooled.
- The ECU may be intervening. Coincidentally, the graphs looks very similar to stock bikes when the throttlebodies closed the plates gradually. We speculate that because the boost temps are so low that maybe the ECU doesn't think the bike has come up to temperature fully and either closes the blades or pulls timing at a target rpm range. To date, no one has been able to verify for certain.
- Possible changes in air flow dynamics due to the plenum core.
- Lack of RG62 Velocity Stacks which smoothed the airflow. The RG62 stacks were good for 6-7hp way up top.

........or perhaps a combination of all the above.
 

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Another factor could be that E85 itself has a cooling effect of over 120 F, not necessarily all of that observed in I AT but by time if full vaporization. That plus intercooler is a lot of cooling.
 

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It sounds like the impeller is cavitating, by finally just spinning it up too fast. Or the ports can't handle the flow. Or both.
 

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@TedG: I thought the same, that the impeller size seemed in the range where increasing its rpm beyond what it is at H2R redline might put the tips supersonic and actually reduce output with yet higher rpm, or lose power from overspeed from another reason, but RG's dyno results with the gears and his tuning showed no indication of any loss at high rpm: quite the opposite.
 

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@TedG : I thought the same, that the impeller size seemed in the range where increasing its rpm beyond what it is at H2R redline might put the tips supersonic and actually reduce output with yet higher rpm, or lose power from overspeed from another reason, but RG's dyno results with the gears and his tuning showed no indication of any loss at high rpm: quite the opposite.
It could be flow, if the engine can't pump the volume, the impeller will cavitate. Think of a vacuum cleaner, listen to the speed of the motor, then plug the intake or the outlet. The rpm will rise sharply because the impeller will cavitate. If there isn't enough air it just spins. This also could be the lack of ram air. Sitting still on the dyno you don't get air. RG may be supplying more air, or a freer flowing exhaust, etc.
 

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Ok two things are happening. Either the intercooler is robbing you of power, or you getting tire slippage on the dyno. Try strapping the bike down a little tighter on the dyno, do a pull and see if that helps. I saw a big power drop just from slippage.
 
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Ok two things are happening. Either the intercooler is robbing you of power, or you getting tire slippage on the dyno. Try strapping the bike down a little tighter on the dyno, do a pull and see if that helps. I saw a big power drop just from slippage.
That is a good thought also. It could be the clutch slipping as well. You can pretty much tell if it is because the clutch will smell funny. Smell it first, do your pull and smell afterward. Usually has a burnt cork smell. But who knows what the clutch is made out of.
 

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This one stumped my tuner as well. Stage 2 gears and EC intercooler. The bike loses power at 12k.
 

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Just to add some more to this thread: My 2015 H2 has a Brock's/Guhl flash, PCV with custom map, and air filter. The power also noses over at 12,000rpm and for LSR I've had to gear it accordingly, rather than to the engine red line.

I recently added the Akrapovic race system and had it remapped, we found several more HP but the characteristic "nose over" at 12,000 is still there.

I'm fairly sure it isn't slippage on the dyno' or the clutch. If the curve carried on to the red line without going over the top there would be a useful power gain. Obviously I'm interested in any solutions or suggestions.
 

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The cam durations sure aren't optimized for past 12,000 rpm, as another possible reason for losing power at highest rpm, yet if that were the cause, why would it be affecting only some bikes and (apparently) not others.
 

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Just to add some more to this thread: My 2015 H2 has a Brock's/Guhl flash, PCV with custom map, and air filter. The power also noses over at 12,000rpm and for LSR I've had to gear it accordingly, rather than to the engine red line.

I recently added the Akrapovic race system and had it remapped, we found several more HP but the characteristic "nose over" at 12,000 is still there.

I'm fairly sure it isn't slippage on the dyno' or the clutch. If the curve carried on to the red line without going over the top there would be a useful power gain. Obviously I'm interested in any solutions or suggestions.
What is your rev limiter set at?
 

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The cam durations sure aren't optimized for past 12,000 rpm, as another possible reason for losing power at highest rpm, yet if that were the cause, why would it be affecting only some bikes and (apparently) not others.
That isn't the cause, as you mentioned it would have to be affecting every bike since they all share the same cams and degree.
 

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This one stumped my tuner as well. Stage 2 gears and EC intercooler. The bike loses power at 12k.
It's the intercooler.
 
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