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J-Series Engine Mounts Compared: Innovative & XLR8 Mounts

J-series Polyurethane Engine Mount Kits Compared: Innovative Mounts and XLR8 Mounts

The J-series engine mount game has been somewhat heavily contested over the years; Innovative versus XLR8. We get calls and emails all the time about these two quality brands from people confused about forum hearsay and old, outdated posts. This article is going to lay out some of the similarities and differences between these two great performance mount kits.

First, a bit of backstory. There seems to be this lingering rumor that the Innovative Mounts are inherently bad because of “donuting” or deformation of the ploy bushings. Factually, there was a thread posted on which discussed the issues with an old Innovative design. Speculation and/or general consensus was that the bushing design used by Innovative was not adequate for the load they were under. The design of the mount and/or bushing needed improvement. What is important to know is that many years ago the Innovative kit was completely redesigned in an aptly innovative way, and that while threads on the internet are relatively permanent, product design and reputation is not. The current design is not susceptible to bushing deformation at all.

Now that that is clear, we'll get the comparo going.

Factory mounts are very good at isolating noise and vibration from the engine. Despite what you might read online, they are actually fairly durable as well. They usually last in excess of 100,000 miles, except in some cases where heavy duty-cycle (aggressive driving with performance mods) can cause them to wear prematurely. It should be understood that changing to aftermarket mounts will noticeably increase both noise and vibration inside the cabin significantly. Whatever polyurethane mount set you choose, it won’t result in fluid filled, rubber-dampened comfort. Your Acura TL won’t feel quite so luxurious with poly mounts in, regardless of the durometer you choose. That said, original mounts can fail with increasing frequency with the intensity of power addition that enthusiasts do these days. If you just need new mounts after 120,000 miles, we might suggest new stock mounts. If you are looking for more performance, read on.

But there is clearly a need for performance polyurethane engine mounts for J-series engines, so here they are. Now, both kits, XLR8 on the left, Innovative on the right:

They look pretty different, don’t they?

The old Innovative kit used to look similar to the current XLR8 kit, but Innovative rethought the loading and potential for problems with front and rear mounts and addressed them by turning the bushings on end. With a lateral mount position, the surface area that carries the weight of the mount is pretty small. With the bushings mounted vertically, the load is carried over a larger area and the bushings have been proven to be much more durable over time, even the softest 60A durometer that presented an issue with the old design.

If the CNC stainless steel bracket on the Innovative mount above looks turned 90 degrees, that is because it is. We were playing with swapping bushings and accitdently left this one off in the pcis.

The rear mount is the same arrangement as the front. The front and rear position mount design are critical due to their need to the loading they take as the engine moves back and forth on and off the throttle. The XLR8 mounts using the lateral bushing layout have been reliable. Our preference is the Innovative method. We don’t try to steer customers one way or the other here, as it seems a matter of preference.

Both mounts use precition cut steel parts which are assembled and welded. One nice feature of the Innovative mount is the individual parts all lock together to locate themselves before welding. The XLR8 design is simpler, but by interlocking the parts before welding there is far less chance of assembling incorrectly before welding. Ultimately, both parts are made in good fixtures that produce repeatable good fitment and we have no complaints about installation on either.

While the front and rear subframe mounts take the brunt of the drivetrain load, the standard engine mount on the right side of the engine tends to fail pretty frequently. Thusly, XLR8 and Innovative Ploy Mount kits both include these passenger-side mounts.

Functionally these mounts do the same thing, but there is no denying the amount of craftsmanship that has gone into the Innovative Mounts rivals the XLR8 ones. If we look at how the load is carried on these mounts, both bushings are mounted laterally. As the engine moves in the mounts, the XLR8 bushings undergo a twisting force, while the Innovative ones undergo a rotational force along the axis of the bolt. As such, there would be more force needed to move the XLR8 mount, putting more stress on the steel brackets. We do have one recorded failure of the XLR8 design here, but it seems to have been an anomoly. We don't see problems with either design in general. Again, we don’t try to steer customers here, but the material and fabrication quality is noticeably more impressive in one of these mounts:

The above shot gives a good look at the shape and size of the Innovative bushings as compared to the XLR8 ones. The Innovative ones are smaller, and have a tapered face to them. Speculation has it that these two factors were contributing to the "donuting" that occurred when the bushings were allowing the mount pins to sag in the material, permanently deforming it. The XLR8 bushings are larger and have flat faces, but these two factors cannot contribute to a more stable bushing. The load is the same. Making the bushing more captive in one area to prevent it from squishing out would only serve to cause it to squish into a different area. The size of the bushing would not prevent the material from deforming either; The reason being, the deformation happens at the point of application of force. Two bushings of the same durometer with a 1/2" hole in the middle are going to deform the same at the hole, whether the OD is 3" or 10".

Thus, with the XLR8 design, we feel, without having measured them, that the stiffness of the softest XLR8 bushings (62A) must be significantly more than that of the softest Innovative bushings (60A); more than the durometers would imply. Otherwise, they would be deforming as well. One of these two is not providing an accurate bushing durometer, it would seem.

But ultimately what difference does it make? We have tested both the 60A and 75A Innovative bushings in our TSX and noticed essentially no difference in vibration between the two. Poly is poly and is going to be uncomfortable.

So there we have it. A real, current-day look at the differences between the XLR8 and Innovative mounts for Honda and Acura J-Series engines. Which one is for you? Take your pick.


07-04-2016 12:10 PM at 12:10 PM
You used the word burnt instead of brunt in your paragraph about the passenger side Mount, FYI.
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Thanks! We've fixed it now.

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