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Stock vs GP3 vs Powerflex Gearbox Mount Differences
Hey everyone,
You have seen me lurking, throwing stuff up on Marketplace (thanks to everyone I have transacted with) and my build thread for F5666. The car is in the middle of the journey to 550hp/600tq, sitting somewhere close by to 400hp at the moment (dyno coming soon). I am obsessive about the build and exclusively do all my own work + a ton of research.
Given how much power is on tap and how its delivered (it gets explosive after 3k RPM), I have always had issues with the factory mounting points on top of the reliability issues associated with them, so needless to say I am always searching for a better solution. I was ready to move to the much more restrictive Direnza mounts but by the time I was ready to purchase they were removed from the market - apparently in an email to me they stated they took them off market b/c they were not happy with their performance and are currently doing a redesign :|
So what's a high horsepower MINIac to do? I started exploring the Powerflex options plus the mounts used in the 300hp factory B48 cars like the GP3, ALL4 Countryman and Clubman JCW for example. I was expecting to be able to drop the Powerflex insert into the GP3 mount to get something stiff with moderate compliance given how much the engine can be tossed around under the hood pushing the power I am. I was in for a surprise, it was physically different to the point the insert will not work with the GP3 mount.
I bought the GP3 gearbox mount (part # 22316886197) as well as the stock gearbox mount (Part # 22316853453) and did some comparison side-by-side and also do some very unscientific tests to see if I could gleam which solution will work better: the factory mount with a Powerflex Street durometer insert vs the GP3 mount.
The pics below show you every angle of the mounts side-by-side. Overall form factor is identical with minor differences in the location of a pinhole on the bottom, a small corner cutoff on the flange of the factory unit and the internal portion of the mount, which on the GP3 looks bigger and is somehow anchored or bound together with a metal insert in the rubber along with a couple bolts. There is also a flange and reinforcement at the top center of the mount above the part that bolts to the transmission. The "bumpers" inside the mount on the front and rear of the bracket that attaches to the transmission are bigger it seems on the factory part vs the GP3 part - this presumably limited forward and aft movement. Curiously, the number imprinted on the rubber center portion is different on each: 220150-3 for factory part vs 220424-1 for the GP3 part.
When you hold the mount down and try to exert pressure on the flange to visually observe amount of movement and resistance, they honest feel nearly identical. This leads me to believe they did not beef up the dampening or stiffness but merely reinforced the mount so it doesn't come apart as easily. Once I dropped the Powerflex mount in the factory mount, it severely restricted its movement and thus made it much harder to induce flex or movement versus the GP3 mount. This will be the solution for me since I am only going up from here in power.
Next week I am installing a twin plate clutch and will install the mount at the same time. I will provide feedback or answer questions for those curious on this little discussed topic.
In the meantime, if anyone wants to buy the GP3 tranny / gearbox mount from me, shoot me a PM.
You have seen me lurking, throwing stuff up on Marketplace (thanks to everyone I have transacted with) and my build thread for F5666. The car is in the middle of the journey to 550hp/600tq, sitting somewhere close by to 400hp at the moment (dyno coming soon). I am obsessive about the build and exclusively do all my own work + a ton of research.
Given how much power is on tap and how its delivered (it gets explosive after 3k RPM), I have always had issues with the factory mounting points on top of the reliability issues associated with them, so needless to say I am always searching for a better solution. I was ready to move to the much more restrictive Direnza mounts but by the time I was ready to purchase they were removed from the market - apparently in an email to me they stated they took them off market b/c they were not happy with their performance and are currently doing a redesign :|
So what's a high horsepower MINIac to do? I started exploring the Powerflex options plus the mounts used in the 300hp factory B48 cars like the GP3, ALL4 Countryman and Clubman JCW for example. I was expecting to be able to drop the Powerflex insert into the GP3 mount to get something stiff with moderate compliance given how much the engine can be tossed around under the hood pushing the power I am. I was in for a surprise, it was physically different to the point the insert will not work with the GP3 mount.
I bought the GP3 gearbox mount (part # 22316886197) as well as the stock gearbox mount (Part # 22316853453) and did some comparison side-by-side and also do some very unscientific tests to see if I could gleam which solution will work better: the factory mount with a Powerflex Street durometer insert vs the GP3 mount.
The pics below show you every angle of the mounts side-by-side. Overall form factor is identical with minor differences in the location of a pinhole on the bottom, a small corner cutoff on the flange of the factory unit and the internal portion of the mount, which on the GP3 looks bigger and is somehow anchored or bound together with a metal insert in the rubber along with a couple bolts. There is also a flange and reinforcement at the top center of the mount above the part that bolts to the transmission. The "bumpers" inside the mount on the front and rear of the bracket that attaches to the transmission are bigger it seems on the factory part vs the GP3 part - this presumably limited forward and aft movement. Curiously, the number imprinted on the rubber center portion is different on each: 220150-3 for factory part vs 220424-1 for the GP3 part.
When you hold the mount down and try to exert pressure on the flange to visually observe amount of movement and resistance, they honest feel nearly identical. This leads me to believe they did not beef up the dampening or stiffness but merely reinforced the mount so it doesn't come apart as easily. Once I dropped the Powerflex mount in the factory mount, it severely restricted its movement and thus made it much harder to induce flex or movement versus the GP3 mount. This will be the solution for me since I am only going up from here in power.
Next week I am installing a twin plate clutch and will install the mount at the same time. I will provide feedback or answer questions for those curious on this little discussed topic.
In the meantime, if anyone wants to buy the GP3 tranny / gearbox mount from me, shoot me a PM.
Awesome doing the comparison dive! I'm about to replace all 3 of my mounts with the Powerflex bushings myself, main motivation being to feel more connected to the car.
I got the powerflex inserts into the Upper and Lower mount just fine, and their fit feels right. The trans mount insert on the other hand feels like it could easily work its way out once normal operating conditions. Me inserting it then wiggling the mount arm by hand makes the yellow insert wanna shimmy out, despite it initially being fully seated. In the pic below, the insert sticks out just from me having wiggled the mount arm for a bit...
In your pic I see you have it pushed in quite far. Did you "aggressively" push it in really deep then not have any issues with it wanting to work its way out? Did you, or would you recommend, a polyurethane adhesive to ensure it remains seated? Does the slot the tranny mount slides into, in the car's frame, have tight enough clearance to keep the insert contained even if it does start sliding out? Did you feel the gear shifts quickly getting less crisp than when you first installed the insert?
Or did I perhaps get a shrunken insert? In hindsight the cylindrical piece at one of the corners of the insert seems like it isn't nearly as beefy as it needs to be, even in official pics of the design
