13100 rpm fourbanger restricted to 9300 redline

[ptuomov]

Trying to approach this from a different direction, this may not be useful. Either the engines are actually making 10% different power, or the power is being made but is being lost in one of them. Start with #1. You say the AFR is the same so the fueling is the same, but do you have any way to measure actual engine airflow or fuel flow? Can you log the ecu data and compare the engines that way? If somehow the airflow is restricted on the weak chassis you would see the same afr on the lambda meter if the ecu tune is good but different maf or map or ve (or whatever your ecu reports) readings. As for #2, these are making about 70 hp (I think you said), so 10% is 7 hp. If you are making the power but it isn't getting to the wheels it must be getting lost due to friction and should show up as heat. I would think that 7 hp (= 5225 watts) worth of heat should show up with an IR thermometer somewhere after a bit of time under load. Make a run on the dyno or a lap or whatever, then take readings on the engine, chain, sprockets, cv joints, rear end, all the brakes, everything you can. One of those cheap ir cameras would be great, or try to video the display on a simple ir thermometer while also showing where the laser dot is aimed and just slowly scan it over everything as soon as you shut down the motor, then do the other car the same way. Good hunting.

Thanks, this is logical.

I believe that the same amount of air and same amount of fuel is going into the engine in both chassis. '

To make sure that it's not an airflow restriction, the air boxes and ducting were swapped also in one experiment.

The injector pulse width wasn't logged into a file, but since this is being run in open loop Alpha-N mode and we're swapping the control boxes, it's unlikely that fuel was different either. That said, we'll look at the injector pulse width explicitly, too. I'm not sure off the top of my head whether there's already a fuel pressure sensor there, so I guess to be completely sure about the fuel flow one would need to compute/log the injector pulse width net of the offset times the square root of the fuel pressure.

I agree that five kilo Watts should show up over time on a thermometer. I have a flir thermal camera for the phone and infrared thermometer. We have to hold the load on the dyno for a minute or so. A 7hp or 5.2kW power loss for a minute will heat 37 kg of steel by 20C, if I did the math right!

[ptuomov]

First thing to check would be your toe alignment.
Too tight press fits of ball bearings in the hubs or fit of the wheel spindles in the bearings is easy to over look and will cause zero or negative clearance.
Drive unit misalignment
Friction seals LU/ LLU type, may be fitted instead of no contact LB/LBB type or Z/ZZ shields if balls.
Tight CV joint ball tracks, bottoming CV
Correct bearings but crush preload on the upright bearings from innacurate assembly, ditto for the sprocket carrier assembly
Brake drag from misalignment, master cylinder adjustment sticky pistons etc.
Slight pitching error on the sprocket teeth is not unknown. Unnecessary O ring chain.
Chain run looks strange on the underside?

All things to go thru and rule out if both chassis ECU's provide the same ignition advance, same fuel, and same throttle angle.

One thing to note is that the chain in this car is half the length of the chain in the bike. It might be especially finicky about alignment, something that was already noted by a poster earlier.

That said, as was pointed out earlier, 7hp additional driveline loss would generate a whole lot of additional heat, so the heat signature should be detectable. The chain should glow like Columbia after a day on the dyno, relative to the other chassis.

[Rick!]

First thing to check would be your toe alignment.
Too tight press fits of ball bearings in the hubs or fit of the wheel spindles in the bearings is easy to over look and will cause zero or negative clearance.
Drive unit misalignment
Friction seals LU/ LLU type, may be fitted instead of no contact LB/LBB type or Z/ZZ shields if balls.
Tight CV joint ball tracks, bottoming CV
Correct bearings but crush preload on the upright bearings from innacurate assembly, ditto for the sprocket carrier assembly
Brake drag from misalignment, master cylinder adjustment sticky pistons etc.
Slight pitching error on the sprocket teeth is not unknown. Unnecessary O ring chain.
Chain run looks strange on the underside?

All things to go thru and rule out if both chassis ECU's provide the same ignition advance, same fuel, and same throttle angle.

One thing to note is that the chain in this car is half the length of the chain in the bike. It might be especially finicky about alignment, something that was already noted by a poster earlier.

That said, as was pointed out earlier, 7hp additional driveline loss would generate a whole lot of additional heat, so the heat signature should be detectable. The chain should glow like Columbia after a day on the dyno, relative to the other chassis.

Right. An IR camera would make short order of hot stuff inspection, assuming a little flat black was applied to the suspect parts. Beat licking your fingertips and listening for sizzling noises.

[MadBill]

"That said, as was pointed out earlier, 7hp additional driveline loss would generate a whole lot of additional heat, so the heat signature should be detectable. The chain should glow like Columbia after a day on the dyno, relative to the other chassis."

Ah, but the coast down numbers are the same between chassis, so not a driveline friction issue, at least not in decel mode...

[ptuomov]

"That said, as was pointed out earlier, 7hp additional driveline loss would generate a whole lot of additional heat, so the heat signature should be detectable. The chain should glow like Columbia after a day on the dyno, relative to the other chassis."

Ah, but the coast down numbers are the same between chassis, so not a driveline friction issue, at least not in decel mode...

Yes, but it could be a misaligned something like a sprocket that tilts or bends worse when being pulled by the engine but tilts straight when pulled by the dyno rollers. Is that possible?

[Momus]

First thing to check would be your toe alignment.
Too tight press fits of ball bearings in the hubs or fit of the wheel spindles in the bearings is easy to over look and will cause zero or negative clearance.
Drive unit misalignment
Friction seals LU/ LLU type, may be fitted instead of no contact LB/LBB type or Z/ZZ shields if balls.
Tight CV joint ball tracks, bottoming CV
Correct bearings but crush preload on the upright bearings from innacurate assembly, ditto for the sprocket carrier assembly
Brake drag from misalignment, master cylinder adjustment sticky pistons etc.
Slight pitching error on the sprocket teeth is not unknown. Unnecessary O ring chain.
Chain run looks strange on the underside?

All things to go thru and rule out if both chassis ECU's provide the same ignition advance, same fuel, and same throttle angle.

One thing to note is that the chain in this car is half the length of the chain in the bike. It might be especially finicky about alignment, something that was already noted by a poster earlier.

That said, as was pointed out earlier, 7hp additional driveline loss would generate a whole lot of additional heat, so the heat signature should be detectable. The chain should glow like Columbia after a day on the dyno, relative to the other chassis.

I'll disagree re the power loss being obvious as severe heating if the final drive or wheel alignment is the issue.

The tyres, if toed, won't blink absorbing and dissipating a couple of horse power each moving through the cooling air as they are.
The other parts also have considerable thermal mass and radiation capacity.
You probably need a set of dedicated wheels and tyres for the rollers.

[ptuomov]

We see the same power loss on an eddy current hub dyno that doesn’t have the tire variable.

I agree that if we just do 9 second passes, the thermal inertia and air cooling will mask any temperature-based inefficiency measurements.

However, I think the difference in heat signatures should be visible in the problem spot if run on an eddy current hub dyno for a minute. The quantity of heat produced by the additional 5.2kW power loss in a minute is over 300 kilo Joules. You’d think that’d show up on a thermal imaging camera? But I’ve never tried specifically that, just done thermal imaging heat shielding for my turbo car, so I’m asking not stating.

[Momus]

Perhaps you will find an engine output related issue that fixes the problem.

I've never temp checked with a gun or camera though have seen the blackened and burnt results of too tight or unlubed rear end bearings after dyno runs.

A decent lathe, fitted with an accurate current meter and the necessary adaptor would perhaps be a way to check final drive losses.

[ptuomov]

It looks like the problem was in the electronic selector / TRE unit and it’s wiring that chooses the A/B Suzuki drive mode and creates the gear input for the ECU (should be the fifth gear). In the process, the random ECU fires problem was likely also resolved…. The remaining power difference between the cars is small. Now we’re cooking.

[MadBill]

ptuomov, could you expand that explanation a bit and define terms (TRE, A/B drive modes, etc.) for us electron Luddites?

Perhaps you mean that the stock bike has a 'power-stifle mode' in the lower gears which was accidentally enabled full-time (in all gears?) in the weaker combo?

[ptuomov]

“ Another point not mentioned earlier is the Suzuki-Drive Mode System, which allows the rider to choose between two different power settings, A and B. With this being a racetrack environment on a sunny California day, we didn’t bother with B mode as it drastically spoils the fun.”

https://www.motorcycle.com/shoot-outs/2 ... tml?page=5

“With activated TRE (Timing Retard Eliminator) both throttle response and acceleration are improved in the lower gears. Also, the bike’s top speed limiter is disabled on 1000+ cc bikes. TRE automatically switches off in Neutral for smooth idle operation and switches back to the selected mode when the gearbox is in gear. If a TRE device is installed on a bike equipped with in-dash gear indicator, the bike’s indicator will show the mapped gear. However, the GIpro will indicate the gear selected regardless whether the built-in TRE is active or not. TRE is disabled by default. To comply with local regulations, do NOT activate TRE mode on public roads.”

https://www.healtech-electronics.com/pr ... ipro/gpat/

[ptuomov]

ptuomov, could you expand that explanation a bit and define terms (TRE, A/B drive modes, etc.) for us electron Luddites?

Perhaps you mean that the stock bike has a 'power-stifle mode' in the lower gears which was accidentally enabled full-time (in all gears?) in the weaker combo?

There was an electrical fault in the various electronics that we use to tell the ECU the drive mode and gear. It caused erratic operation, ECU’s burning, and other issues that also now explain the lower power and wrong maps being selected.

[MadBill]

Wow, talk about obscure faults! Must have been high fiv...err elbows all around when you nailed it.

[ptuomov]

90 hp @ 9300 RPM is just under 51 lb-ft.

https://www.gixxer.com/threads/stock-k7 ... 72&slide=0

That's a K7 GSXR600 ('06'-07ish), and @ 9300 it's making what....less than 40 lb-ft? Sure, there's some drivetrain loss there but bikes are pretty efficient. I don't see you gaining 25% torque at that RPM point by playing with stock variations of heads and cams. The new latest and greatest GSXR600 is rated at ~45 lb-ft peak, and that's way above 9300.

This back of the napkin math shows you won't be racing against anyone with 90 hp that isn't heavily, HEAVILY cheating. Your competition will have a heck of a time making 80 hp if they're following the rules.

Yesterday, we were at a dyno which generally replicates stock motorcycle engine power levels claimed by factories for stock bikes and by race teams for race bikes. After two summers of tinkering, we are at 78hp at 8800rm and 64Nm at 7600-8600rpm at the wheels on 98E5 pump gasoline. The free roll driveline loss estimate at peak power rpm at the dyno is slightly over 9hp, which would put us to 87hp at the crank if the driveline loss estimate is taken seriously. This is from four 150cc cylinders with a four valve head.

Compared to the stock bike at those rpms, the cylinders are now filling so much better than stock that the measured torque keeps going up as we reduce ignition timing up to 6 degrees. Having to pull off six degrees of ignition advance to get best torque in the 7600-9200 range tells me that the bike engine was obviously not optimized for this rpm range (the bike engine shows signs of life at 10k rpm) and our longs and skinny intake and exhaust are doing something beneficial.

[ptuomov]

Yesterday, our driver won the national championship with the headers discussed in various Speed-Talk.com threads:

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