Solved: CD009 trans on SR20DET - Vibration at 4000rpm? (Posts #79, 108)

[jr_ss]

Have you given thought to trying other mounts? Such as but limited to Nismo, energy suspension, etc? It would be interesting to see this comparison.

[slider2828]

Originally Posted by canadians14sr20det

So I tested this with the driveshaft disconnected, no change at all. It is entirely related to the mass of the transmission and the way the trans case carries the vibration to the chassis. Weight of oil will help gear chatter related to switching to a single mass flywheel, but won't change the fact this trans does this in neutral as well. Resonance is a function of the natural frequency and mass of the object, in this case there isn't much you can do to the trans to change it.

Thanks for your clarity.

I thought you were revving the car to 4500 and beyond... Just thinking oil should help it a bit and I do like the idea of trying different mounts, maybe with lower durometer like driftfreaq mounts.

[spooled240]

This is very interesting as I have been trying to figure out a resonance vibration on my KA for years. Contrary to your experiences, the vibration in my car is felt anytime the engine is revving around 2200 rpms (free-rev clutch in/out or driving in any gear) which means the source is the engine itself. Replacing the harder Nismo engine mounts with softer, liquid-filled motor mounts perhaps off an older BMW 5 series is what I'm going to try.

Positive rep for the very methodical and technical approach to testing and updating this thread with findings!

[canadians14sr20det]

Originally Posted by TheRealSy90

I may be interested in buying one of these mounts from you.

Originally Posted by mr.nismo.

Same if I have issues with my setup as well. I'm using the gk mount so we'll see

Sent from my Note 20 Ultra using Tapatalk

I won't be building and selling these as I don't want the headache that goes with all that. I will however provide the plans for whatever I build so anyone else can replicate it, or at least have a fabricator build it for them.

Originally Posted by jr_ss

Have you given thought to trying other mounts? Such as but limited to Nismo, energy suspension, etc? It would be interesting to see this comparison.

I have already done this. I've tried:
- OEM s14 mount
- OEM s14 nismo mount
- OEM 350z mount
- OEM 370z mount
- Generic energy suspension bushing

The 350z mount with the damper bolt was the best, but only marginally better than an OEM s14 mount. Frankly none work well as they are all not designed to work in this application.

Originally Posted by spooled240

This is very interesting as I have been trying to figure out a resonance vibration on my KA for years. Contrary to your experiences, the vibration in my car is felt anytime the engine is revving around 2200 rpms (free-rev clutch in/out or driving in any gear) which means the source is the engine itself. Replacing the harder Nismo engine mounts with softer, liquid-filled motor mounts perhaps off an older BMW 5 series is what I'm going to try.

Positive rep for the very methodical and technical approach to testing and updating this thread with findings!

This is probably normal. The second order vibration moves lower in the rev range as the 4 cylinder gets bigger. As the KA is a bigger engine this would make some sense. You can use an app like Vibrations! on your phone to determine the frequency of the vibration. If you have a vibration of ~70Hz at that RPM it's a second order vibration and your plan for the 5 series mounts would probably help.

[jr_ss]

Originally Posted by canadians14sr20det

I have already done this. I've tried:
- OEM s14 mount
- OEM s14 nismo mount
- OEM 350z mount
- OEM 370z mount
- Generic energy suspension bushing

The 350z mount with the damper bolt was the best, but only marginally better than an OEM s14 mount. Frankly none work well as they are all not designed to work in this application.

I figured this would be the results. It only makes sense, since they are sold as a higher durometer rubber. Thanks for confirming!

[foreverdeath]

Did you ever make those plans? I get the same vibration with a cd009 and turbo K24A2. After 4k rpm the chassis is vibrating pretty intensely, but flat out I cant notice it feel it.

[mechanicalmoron]

Trying it without the damper does not eliminate the damper - it simulates a really-bad-case (I only don't say worst because half a damper could be even worse... but worst possible, right?) damper damage scenario - it's highly inadvisable to rev it like that without a damper, even briefly.

[canadians14sr20det]

Originally Posted by foreverdeath

Did you ever make those plans? I get the same vibration with a cd009 and turbo K24A2. After 4k rpm the chassis is vibrating pretty intensely, but flat out I cant notice it feel it.

Yeah that makes sense. Under full throttle the time you spend at that rpm is limited so the chassis has trouble getting into resonance, as well as the gear lash stays tighter inside the trans.

I did make the mount but it also wasn't a huge help (though it worked great free revving the engine). Under cruising load the vibrations are being transferred from the trans through the driveshaft to the rear end. I have solid subframe mounts so that probably isn't helping. Guessing most of the people on here have solid subframe mounts as well. Anyways, here's my design:



The rubber mounts on the side mount to aluminum L-brackets that bolt to the stock location. Like I said, works great with no load on the engine, just free-revving. Inspired by this jaguar mount design:



Since this still doesn't work under load I'm gonna try switching my subframe mounts from solid aluminum back to nismo rubber bushes. If that doesn't work I may try a carbon fiber driveshaft. I'd like to throw a dual mass flywheel on or a guibo on the driveshaft but both of those options would require crazy custom machining. Honestly I may say fuck it and go back to a 5 speed.

Originally Posted by mechanicalmoron

Trying it without the damper does not eliminate the damper - it simulates a really-bad-case (I only don't say worst because half a damper could be even worse... but worst possible, right?) damper damage scenario - it's highly inadvisable to rev it like that without a damper, even briefly.

I have no idea what you are talking about. There is no damper that is integral to the CD009.

[spooled240]

I think swapping the solid subframe bushings out is a good plan. I have solid aluminum bushings on my subframe and I get noticeable vibrations from the rear of the car right around 2200rpms in lower gears. 2200 rpms is also where I get resonance on my KA 5 speed. I just ordered Nismo subframe bushings because it is bothering me so much.

[foreverdeath]

I fixed the vibrant on accident... I redid the rear most hanger on my exhaust hoping it would make the drone less intense on the highway, as it had one of these cheap "hangers" welded to the the frame rail. It worked, it was a bit quiter at highways speeds, I could hear the 525LPH walbro at idle, and my 4k vibration was gone. I do still have a mild vibrant between 3500 -3750rpm but that's probably from using poly leaf spring bushings as custom motor mounts.

[canadians14sr20det]

So interesting development on this, Taylor Ray built a similar mount for his K24 BMW trans combo. Seemed to solve his problem mostly.

https://www.youtube.com/watch?v=dSZSMsZ604Q

[slider2828]

I think he is on zilvia, because he mentions something about someone doing a similar thing lol.... I wonder if we can use a mount with a low durometer? Might be better? SR with CD009 and valve springs is a easy solution.... I wonder if safe?

[canadians14sr20det]

Originally Posted by slider2828

I think he is on zilvia, because he mentions something about someone doing a similar thing lol.... I wonder if we can use a mount with a low durometer? Might be better? SR with CD009 and valve springs is a easy solution.... I wonder if safe?

The way he did it (welding the spring to a plate) is definitely not safe. You never want to weld a spring, it'll break eventually. See my photos above for a better way to do it.

However I think I now finally have solved the issue. I cracked my subframe, so over the winter I swapped it out with one with GK tech reinforcement plates and nismo subframe bushes. Vibration is like 99% gone. I understand whats going on and why the cd009 is so brutal on an sr car. I'll try to explain.

Stock 350z setup:
- 6 cylinder
- Dual mass flywheel
- Soft Trans mount
- Carbon driveshaft
- Very soft subframe bushes

With a modified SR 9/10 you lose literally all of the above. You can't add a DMF or 2 extra cylinders to an sr easily, so what fixed it for me is:
- Soft trans mount (I used valve springs, but I'm almost certain a stock 350z mount would be fine)
- Soft(ish) subframe bushes (nismo)

I'm convinced that going back to a 2 piece or a carbon driveshaft would bring my car back to almost OEM levels of vibration.

[jr_ss]

Originally Posted by canadians14sr20det

The way he did it (welding the spring to a plate) is definitely not safe. You never want to weld a spring, it'll break eventually. See my photos above for a better way to do it.

However I think I now finally have solved the issue. I cracked my subframe, so over the winter I swapped it out with one with GK tech reinforcement plates and nismo subframe bushes. Vibration is like 99% gone. I understand whats going on and why the cd009 is so brutal on an sr car. I'll try to explain.

Stock 350z setup:
- 6 cylinder
- Dual mass flywheel
- Soft Trans mount
- Carbon driveshaft
- Very soft subframe bushes

With a modified SR 9/10 you lose literally all of the above. You can't add a DMF or 2 extra cylinders to an sr easily, so what fixed it for me is:
- Soft trans mount (I used valve springs, but I'm almost certain a stock 350z mount would be fine)
- Soft(ish) subframe bushes (nismo)

I'm convinced that going back to a 2 piece or a carbon driveshaft would bring my car back to almost OEM levels of vibration.

Have you given this a thought?

https://www.vibra-technics.com/nissa...ia_200sx_240sx

[slider2828]

Could you use just a softer durometer mount like a driftfreaq mount? I also have seen the importance of pinion and drive line angles which have make a big difference in higher speed.

I thought this was super neat and downloaded the app for when the car is back on the ground.

https://www.motortrend.com/how-to/15...le-finder-app/

[97kouki1J]

I don't know how many people here still care or are still following but


TF works now makes a s14 CD009 Cross members that intergrates the original cd009 transmission mount

[slider2828]

It only looks like it works with with maverick adapter. I am asking if it will work with mazworx... i like the design

[slider2828]

Hi all. I finally finished this swap and dealing with this vibration. I am using mazworx swap kit and drift freaq engine and tranny mount. Whay i have found is probably with driveline angle. With this kit and 1/4inch plate yo raise the tranny, the angle of the output shaft points at 2.3 degrees up and the shaft remains at 1.3 degrees down making a v angle. This is too steep. Long story short the output shaft of the diff pinion should be equal opposite of the shaft. So the best angle is try to get nose of pinion 1 degree down if your output shaft is point from tail to front of the car up 1 degree.

Or better expained try to get your driveshaft angle as close to 0 as possible.

[mrmephistopheles]

Originally Posted by slider2828

Hi all. I finally finished this swap and dealing with this vibration.

I'll update the thread title.

[slider2828]

Originally Posted by mrmephistopheles

I'll update the thread title.

Cool thanks!!

I am going with some bmw spec e46 shorty engine mounts. Based on the research it should be close to 57mm in height. I am shooting for the engine mount to be 58mm...

For posterity,
GTR and Z32 is too tall 79mm
Nismo sr20 engine mounts 73mm
Drift freaq is 69mm
Gktech is 65mm
Condor speed spec e46mm should be 57mm as they claim it drops the engine 10mm off stock which is 67mm...

Will report back but its 100% drive angle for sure because diff was inspected by 2 reputable rear engine shops and cd009 is 30k miles and basically new.

[bl3ujay07]

Keep us updated! I just finished my swap with the SRVQ kit as well. I also am using the drift freaq motor and transmission mount so if it the issues is resolved for you, I?ll be placing an order as well! Thanks for keeping this thread alive!

Originally Posted by slider2828

Cool thanks!!

I am going with some bmw spec e46 shorty engine mounts. Based on the research it should be close to 57mm in height. I am shooting for the engine mount to be 58mm...

For posterity,
GTR and Z32 is too tall 79mm
Nismo sr20 engine mounts 73mm
Drift freaq is 69mm
Gktech is 65mm
Condor speed spec e46mm should be 57mm as they claim it drops the engine 10mm off stock which is 67mm...

Will report back but its 100% drive angle for sure because diff was inspected by 2 reputable rear engine shops and cd009 is 30k miles and basically new.

[slider2828]

Originally Posted by bl3ujay07

Keep us updated! I just finished my swap with the SRVQ kit as well. I also am using the drift freaq motor and transmission mount so if it the issues is resolved for you, I?ll be placing an order as well! Thanks for keeping this thread alive!

Are you getting vibration? Heres othe tricks that really smooth out the tranny. I use amsoil tranmission oil and I hated the notchiness of the shifter from gktech so i added a super heavy weights shift knob and got a 1 inch extension from ebay. Feels so good.

My rear end is diff rear bushings is gktech and then front diff bushings is solid spls. I tried gktech but the vibrations exploded the bushings in the front.

Make sure you measure all driveline angles. Its important.

[slider2828]

So got the condorspeed bmw mounts and measures 61.7mm. What i dont like is that it is solid delrin. I am asking what height is the vibra mounts as well... i think it needs to be close to 60mm

But will try the condorspeeds and see if that helps

[slider2828]

Well that was dumb.... So took out drift freaqs and measured his original set of yellow engine mounts. Over the 12 years it basically is now also 61.9mm.... Lol it permanently deformed over 7mm as I know his original was 69mm....

The Condorspeed E46 spec fits perfectly but you just have to shave down two nubs on it.... The driveline is nearly straight after I put literally a 1.2inch lift to the transmission. So the CD is literally touching the top of the shifter tunnel and the driveline is basically straight....

let's see how the noise is now.....