2013~2016 CX-5 Balance Shaft Delete

Nelson de Leon said:

I think based on what you have posted sir, removing the BS would equate to better fuel economy. However, let's talk of purpose. I'm sure the BS is there not to provide just better mileage but for a lot more reasons.

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The main purpose of most balance shafts are to dampen unwanted vibrations from the motor. The motor is already “balanced”. It is setup for only a certain rpm range and not actual whole rev range. So when removing it you shouldnt feel vibration every where in the rpm range. For example in the sentra (with oem motor mounts) I noticed slight vibration at around 4k-4.5k area only. Other cars might have slightly broader range of vibration or start from lower or higher rpm. Some car companies install balance shafts on the US vehicles but leave them out for the same motor/model that are sold in other Regions . Balance shafts are typically found in in inline motor vehicles , example inline 4..

thejeans said:

i ran my 2.3L mazda3 without a balance shaft for nearly 100k. the Balance shaft delete was a popular mod for the naturally aspirated 3 guys.
it allowed the engine to be a bit more free revving (comparable to going from a stock flywheel to a lighter flywheel) wasn't much of a hp gain nor did i see a huge mpg gain.

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Different motor brands will react differently. Fortunate for myself with the Sentra 2.5 L motor I cant say I felt HP but I noticed the MPG improvement that made it well worth the effort. I also noticed it revved quicker in neutral. Who knows, the CX-5 motor might react same way as my sentra, better, similar to your 2.3L or even less difference . We wont know unless someone actually removes it.

4G63T said:

Different motor brands will react differently. Fortunate for myself with the Sentra 2.5 L motor I cant say I felt HP but I noticed the MPG improvement that made it well worth the effort. I also noticed it revved quicker in neutral. Who knows, the CX-5 motor might react same way as my sentra, better, similar to your 2.3L or even less difference . We wont know unless someone actually removes it.

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Im going to guess that the 2.5 will react similarly to what the 2.3's did. slightly freer revving but not much else.

Is this B.S. still going on? Really? Will somebody give that poor kid a high school physics book?!!??!!!

A balance shaft adds ONLY rotational inertia, like a heavier flywheel, while *cancelling* vibration from the secondary imbalance of the crankshaft. A few plain bearings cannot add enough friction to make a "free'd hp" available. Pluuuueeese!

I went from a 17lbs flywheel to a 8lbs flywheel on the RX-7 and the engine response was way better, however my MPG was no different. We are talking a 8lbs drop here!

ColtX-5 said:

Is this B.S. still going on? Really? Will somebody give that poor kid a high school physics book?!!??!!!

A balance shaft adds ONLY rotational inertia, like a heavier flywheel, while *cancelling* vibration from the secondary imbalance of the crankshaft. A few plain bearings cannot add enough friction to make a "free'd hp" available. Pluuuueeese!

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Im not sure if you even read this thread because I did not mention anything about friction of bs bearings causing the resistance.

Anyways here are different motors before and after dyno’s. As said before different car motor designs and their balance shaft will have different effects. Some you may not even notice any difference other than increased vibration. Sometimes people remove them not for the minimal hp they may free up, but to avoid the risk of the bs failing. Remember this thing spins twice the rpms of the motor.

Honda Civic Dyno :
http://www.tdi-plc.com/great-gains-on-civic-type-r-fn2-with-toda-balancer-shaft-killer-kit/

This DSM gained 16whp and 18wtq :
https://www.youtube.com/watch?v=L-zTxKbFjBY

Post 3 has the dyno. The MZR 2.3 did not have much of a difference worth the effort.
https://www.mazdas247.com/forum/sho...-Balance-Shaft-Delete-BSD-Kit-by-hate_romania

Read here. https://www.w8ji.com/rotating_mass_acceleration.htm

You can gain insight into how a spinning mass such as a tire or flywheel or w/e stores (robs) energy.

4G63T said:

Im not sure if you even read this thread because I did not mention anything about friction of bs bearings causing the resistance.

Anyways here are different motors before and after dyno’s. As said before different car motor designs and their balance shaft will have different effects. Some you may not even notice any difference other than increased vibration. Sometimes people remove them not for the minimal hp they may free up, but to avoid the risk of the bs failing. Remember this thing spins twice the rpms of the motor.

Honda Civic Dyno :
http://www.tdi-plc.com/great-gains-on-civic-type-r-fn2-with-toda-balancer-shaft-killer-kit/

This DSM gained 16whp and 18wtq :
https://www.youtube.com/watch?v=L-zTxKbFjBY

Post 3 has the dyno. The MZR 2.3 did not have much of a difference worth the effort.
https://www.mazdas247.com/forum/sho...-Balance-Shaft-Delete-BSD-Kit-by-hate_romania

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You have misinterpreted the results. A reduction in rotational inertia CANNOT result in a real increase in HP. No freakin' way. A misapplication of an inertial dynomometer can show a FAKE increase, but never a real increase. NEVER.

ColtX-5 said:

You have misinterpreted the results. A reduction in rotational inertia CANNOT result in a real increase in HP. No freakin' way. A misapplication of an inertial dynomometer can show a FAKE increase, but never a real increase. NEVER.

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It's not an increase in power, it's "freeing" up power that's already there but not spent on rotating the bs. I should have been more clear. On the dyno it may show as an "increase" but it's not an actual increase if that make sense .

4G63T said:

It's not an increase in power, it's "freeing" up power that's already there but not spent on rotating the bs. I should have been more clear. On the dyno it may show as an "increase" but it's not an actual increase if that make sense .

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I think that would be the correct way to spin it.

Just like if you put 70lbs wheels on a car and dyno it vs 35lb wheels dyno would extrapolate a lower HP number for the heavier wheels.

4G63T said:

Lets talk about how we can delete the Balance Shaft on the SkyActiv-G 2.5 .

The Balancer Unit weighs around 17 lbs and adds resistance to the motor. Removing so would free the motor from wasting energy rotating it twice the speed of the crank from idle to all throughout the RPM range.

Previous Experience with BS delete:

Back in 2003-2004 I removed the BS from my 2003 Nissan Sentra SE-R Spec V . I gained 5-6 MPG’s on the QR25DE motor (2.5L 4 cylinder). There was a little Power gain about 8-10 hp. In addition, it took about a qt more oil due to the extra space created when deleting the BS. There was ver so slight vibration around 3.5k RPM’s . And between 0-10 scale, I would say the vibration was around a 1-2 depending if you are very sensitive person.​

Difference between the Mazda 2.3 Balance Shaft and Skyactiv-g 2.5:

From my observation, the 2.3 Balancer Unit can be removed simply by unbolting and dropping it. The Skyactiv-g 2.5 motor can not be deleted the same way. Unfortunately for us 2.5’ers , the Balance Shaft is Spun with a chain that is shared with the Oil Pump. See image below.​

Compared to the SkyActiv-G 2.0 without Balance Shaft:

The 2.0 does not have Balancer Unit. It simply has a chain from the crank that spins the oil pump and chain tensioner. Image Below .​

The Possible How:

I’m assuming both blocks (2.0 and 2.5) are very similar and maybe the oil pump parts are interchangeable on both motors. To delete the BS, we can probably do so by installing the 2.0 oil pump chain and tensioner after removing the Balancer Unit? Then obviously we would need to plug the deleted BS oil feed on the block. What will be a headache added is if the chain is not able to be disassembled to install/remove and needing to remove the crank/utility pulley etc..

Another option is if someone/vendor made a idle sprocket we can install in place of the balance shaft. Maybe something else to which we can take apart the BS case remove the balancers, put in the idler sprocket and install the unit/case back.

What you guys think ?

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Hi, I have a Mazda 6 with Skyactive-G 2.0l. I feel vibrations on the steering wheel even with the car parked, especially when revving up to around 2500 rpm. At idle (say 700-1500rpm) I feel no such engine vibrations at all. The vibrations are of the type like holding the electric toothbrush or a smoothie mixer. I am probably sensitive to these type of vibrations.

Can you confirm that the 2.0l Skyactive-G does not have a balancer shaft?

Someone on YouTube mentioned, that acutally the Skyactive-G 2.0 in Miata/MX-5 does have a balancer shaft. Maybe Mazda makes couple of different versions of Skyactive-G 2.0l?

I was brfiely sitting the in the 2.5l Skyactive-G Mazda6, and there were zero such vibrations.

As far as I know Ecoboost 2.0l does have a balancer shaft, and I think premium engines (BMW, etc...) have balancer shafts even if they are below 2.0l. Skyactive-G is a long stroke engine, which tells me that it is actually more prone to the type of vibration that is taken care by the balancer shaft. So, I am surprised why Mazda would avoid the balancer shaft in the 2.0l Skyactive-G. Maybe in turbo motors balancer shaft is there to protect the turbo? (but I cannot believe that, turbo must withstand all kinds of road vibrations etc.).

So, is it pure cutting the corners by Mazda, or is there any explanation of the missing balancer shaft in Skyactive-G 2.0l? Surely, no manufacturer would mount expensive and bulky balancer shafts if it was not really necessary.

Any comment on this issue would be very welcome.

Miata.net says the ND 2.0 has no balance shaft and pics show no location to drive them.

Typically, engine vibrations from I-4s less that 2.3l are low enough that no balance shaft is needed. That the stroke is under-square matters little as the "opposite" piston counters the primary vibration mode. If the Ecoboost 2.0 has a balance shaft, remember, it is used in Lincolns and those customers expect more smoothness.
Yes, deleting or not building the S-G 2.0 is a cost saving move. Since is isn't needed, that's a really good thing. Mazdas don't have to be priced closer to Lincolns. The lower rotating mass also allows the engine to rev quicker, too, improving the sporting feel of a Mazda.

Thanks for the comments. I did more testing. My car has a vibration resonances at around 1250 rpm and 2500 rpm (when parked and in neutral, manual transmission), so it seems like frequency doubling. Hard to tell with 5000 rpm, as this car does not rev to more than 4000 rpm when parked. I tried on neutral gear when driving, and I did not feel a clear resonance at 5000 rpm, and certainly 5000 rpm is not worse than 2500 rpm.

The resonance at 2500 rpm feels on the steering wheel like holding the kitchen mixer or electric toothbrush. But it is not a huge vibration, maybe many people would not notice it or would not care.

To me this all means it is probably not a balance shaft issue. This is because probably balancer shaft is targeted towards vibrations at some particular frequencies. According to physics of this, these kind of vibrations should increase a lot with rpm, something that does not happen in my case. Also, it is not that I am sensitive to every engine vibration, I have driven around 1 million km in various passenger cars over the past 20 years and they certainly vibrated a bit, especially that some of them were diesels.

So, I suspect some small issue inside the engine, maybe on the connection between engine and transmission, maybe a slightly bent crank. I doubt I have bad engine mounts because the car is new and they look good by visual inspection. I think there is no chance to sort it out with Mazda, and I am planning to sell the car (and unfortunately lose a lot of money). I think someone else might like the car, it actually drives pretty well.

What do you think?