4th Gen - Aluminum Sub-frame Spacer Modification
 

Over the past couple of months, I have received several requests to post information on the sub-frame spacer modification. It has taken a couple of months to try several different products and approaches to finally settle on a method that I feel comfortable sharing.

All total I must have spent $400 on an assortment of poly bushings, washers, ceramic magnets, and spacers to finally reach an approach where the modification can be repeated in the $90 to $100 per vehicle range. Since I paid $90 for the original set of spacers that I'm replacing with a hopefully better product, I think it will be worth it. I want this modification to last for several years.

This modification uses a combination of parts from the following vehicles:

1) Nissan 300ZX Aluminum Sub-frame Spacers
2) Nissan Titan Truck PRG Delrin Suspension Spacers
3) Subaru WRX - Perrin 4268 Sub-frame Bushings


Installation Vehicles

1998 Maxima GLE – Recently converted to SE suspension. Note initially this modification was made to the stock GLE sub-frame. Later the 98 GLE was converted to use the triangular sub-frame braces from a 97 SE. Pictures of how the bushings look in both the stock GLE and upgraded SE type suspension are provided.
1999 Maxima SE – This is the 2nd installation where I used this modification.
Post Installation Pictures

Front 300ZX Aluminum Subframe Spacer with PRG Delrin Titan/Armada spacer and flat washer.

Attachment 12049

Rear 300ZX Aluminum Subframe Spacer with Perrin 4268 Subaru WRX Bushing

SE Type Suspension

Attachment 12050

Non-SE Type Suspension

Attachment 12051

The Problem

Space between the sub-frame mount post and the body results in a loose sloppy feel when driving over rough places in the road and lowers the amount of feedback from the rack to the driver.

Also, when the sub-frame upper post rubs against the body it can make a creaking noise.

Attachment 12052

Roughly 3 years ago, I purchased a set of plastic spacers to tighten subframe movement. Unfortunately, the upper spacers were not thick enough to completely stop the movement. Since the upper spacers are C-shaped, the upper rears spacers eventually worked loose and fell out on the street somewhere.

Attachment 12053

The old spacers helped after the initial installation. Since I could see the gap that remained between sub-frame post and the body would eventually allow the upper C-shaped collar to fall out. So I had to use Gorilla Tape as a temporary measure to wrap the area until I could come up with a tighter solution.

Looking back, I could have stacked up additional washers on the bottom
post to remove slack. By then, I had already lost one of the rear spacers. Unfortunately, I just did not have a solution at the time when I realized the old spacers were too loose. Since the spacers are no longer available and the seller was not responding to email when I attempted to buy another set, I decided to find a repeatable solution using a combination common parts from other platforms.

Old to New Parts Comparison

The old parts are in the upper row.
Attachment 12054

Comparing the Perrin rear lower bushing to the original lower spacer.


Here's a picture of the new Perrin 4268 bushing that is used on a Subaru WRX compared to the old rear lower spacer. The Perrin bushing is definitely thicker and is capable of absorbing shock that may be transmitted to the rear part of the sub-frame.

Attachment 12055

Cost Summary

Aluminum 300ZX subframe spacers $25 to $28 depending on color. Shipping free from eBay sellers.

PRG Delrin Titan spacers (set of two) $20 + shipping

Perrin 4268 WRX bushings ~$10 + shipping.

Fastenal 33098 Washers $1 to $2 x 2 = $4 high

Harbor Freight Step Drill Bit $16 (with a 20% off coupon) to $20

Rough Estimate Total $90 to $100 depending on shipping costs.

Parts Sources

Perrin WRX Bushings Part Number 4268
300ZX Aluminum Subframe Spacers

Multiple eBay sellers – Prices vary based by color. Just search for 300ZX aluminum sub-frame spacers and go for the best deal.

Red

http://www.ebay.com/itm/Aluminum-Sub...RYbvZO&vxp=mtr

Silver (I bought silver because I didnÂ’t want a color to get scratched off during installation.)

http://www.ebay.com/itm/Rev9-SILVER-...5Vbew2&vxp=mtr


Flat Washers

Fastenal

SKU 33098

https://www.fastenal.com/products/details/33098
NOTE: The washer is listed as 1 - 1/8 ID but you can see it actually has a larger ID.

Washer Inner Diameter

Attachment 12056

Washer Outer Diameter


http://i286.photobucket.com/albums/l...psywwmrb9q.jpg

https://www.fastenal.com/products/details/33098

PRG Delrin Titan Spacers

Approximate Cost $20 for a set of two.


Attachment 12057
Attachment 12058

Harbor Freight
http://www.harborfreight.com/2-piece...lls-96275.html

Attachment 12059
Attachment 12060

Harbor Freight 24" Tire Iron

This $5.99 Harbor Freight Tire Iron worked best for wedging in between the rear subframe mount area and the body to "open a gap" so the aluminum collar can be inserted. It came in handy when I needed to push the down on the subframe during installation.

http://www.harborfreight.com/24-inch...ron-93230.html

http://www.harborfreight.com/media/c...mage_21240.jpg


Installation Notes

Tools: 19mm socket for sub-frame mount bolts - for SE models there are two 14mm bolts that hold the additional support plate to the body.

Perrin Bushing Location - SE Suspension

http://i286.photobucket.com/albums/l...psbehsm6of.jpg

Perrin Bushing Location - non-SE suspension

Attachment 12061

Rear Spacer

You will need to use a pry bar to push the sub-frame downward and away from the body so the sub-frame collar can slide over and into the sub-frame mount position. Remove both rear sub-frame 19mm bolts and loosen the fronts to provide ample clearance for sliding the aluminum collars into position. This was relatively easy the passenger side but required more effort on the driver side. Where you insert the pry bar depends on the size and length of the bar.

Here's a picture of the location where I inserted the pry bar at the rear of the sub-frame to push it down so the C collars (front and rear) would slip around the old rubber mount. It is not necessary to cut the old rubber mount or to widen the opening of the C collar after the sub-frame has been pushed down and out of the way using a pry bar for installation. Using this approach allows the new C collars to fit tight around the old rubber post bushing so they will not fall out.

Attachment 12062

After you slide the new C collar into position, be sure to center the spacer so the most contact is made between the spacer and the upper part of the sub-frame mount post before tightening the 19mm nut on the sub-frame post stud bolt.

http://i286.photobucket.com/albums/l...psngr1ov5y.jpg

Front Spacer

Like the rear, a pry bar will need to be used to push the sub-frame down far enough for the aluminum collar to clear the sub-frame post. The 19mm bolt and square washer will need to be loosened and removed so the sub-frame post can be lowered enough to allow the collar to clear the upper mount post.

Note on the driver side, I could not get enough clearance for the collar to slide around the post. I used a rubber hammer and tapped the collar into position. Since the inner post is made from rubber, it won't hurt it. Once the post has been cleared, the collar will be loose for adjustment and final tightening like you see in the picture below.

Attachment 12063

Note that the PRG Delrin Titan spacers will need to be bored out to an Inside Diameter of 1-1/4 inch.

Attachment 12058

Use care and wear eye protection when operating a drill and performing this operation to bore out the spacer. How you choose to secure the spacer while boring out the hold will depend on your skill level, and tools available. I used a small drill press vice to hold the spacer in place while I drilled out the ID. I could have used vice grips to clamp the spacer while holding it down. Be sure to stop periodically to clear away shreds of plastic remnants from the sides of the spacer that will appear as you start to bore out the ID.

Disclaimer

This mod should be only used for experimental AutoX track type vehicles that operate on smooth road surfaces where the driver needs maximum feedback from the suspension to make quick decisions while driving a slalom type competition course.

If you drive on rough unpaved roads, cobblestone streets, and traverse large potholes often, then depending on your tire/rim size, you may find the direct feel between the sub-frame and the body to be harsh, uncomfortable, and hard to handle.

For example, this modification on the 98 model with 17" wheels and 235/45 tires has a completely different feel when compared to the 99 model with 18" rims and low profile tires. A normal driver would find this modification on the 99 model, with an already stiff suspension, to be too harsh for anything other than smooth interstate driving.

So consider this modification at your own risk.

Love those stepper bits... Ever done any autocross Craig? I never have, but it's always what I've wanted to do... seems like this would be a great start for Maximus Autocrossios! My 19" TSW's are bumpy enough... I love the look, but really not happy with the ride quality.

Hey the price for Titan Delrin spacers has come down by $20 since the first post. Now PerformanceLifts has agreed to sell only two for $20 + shipping.

Yes to AutoX. Actually, I got my youngest son started in SCCA AutoX back when he was 15. I would let him and his buds take out the Q45 to learn how to drive at the track. He plans to introduce the 99 model to AutoX maybe this summer> That is if I'll ever stop modifying it.

He played a XBox games when he was growing up like Forza IV and others that developed his eye to hand coordination and AutoX course cone recognition. So when he was old enough to drive on a real track, he already knew the cone signals and how to turn accordingly.

He was 15 in this picture. I think getting an early start with AutoX training and driving makes for a much safer driver. You understand and respect the limits of your vehicle and driving conditions.

Attachment 12037

Here's where learned about aluminium subframe spacers in the link below. It would be great if we could use the lower spacers also, but our posts are too small so I had to improvise with the Titan & WRX bushing combo.

http://www.nicoclub.com/archives/ins...initi-q45.html

As you can see from the following picture of my Q45, I'm running aluminum subframe spacers in some form or fashion on everything I own. That is except the Hondas and they don't really matter. :D

Attachment 12038

Updated with Fastenal SKU 33098 zinc plated automotive washer info.

Great thread, thanks for posting up all of the details and links! I still have the delrin ones on my car from 10 years ago or whenever they came out, but it's good to know there are some other options out there if needed. Remind me, the stock bushings are just rubber, right? Did they just slide off or did they need to be cut/burned?

Thanks for the question. Actually the delrin C shaped collars for the rear I bought years ago fell out. I guess the ones I got were too thin and the opening was too wide for them to stay in for the long haul.

Are the stock bushings rubber? Correct. If I remember correctly there may be an end piece that looks like a metal washer.

Did they just slide off or did they need to be cut/burned?

No removal, cutting, or burning of the old rubber bushings required.

That is what makes this suspension mod one of the easier ones to install. :)

Also, since the old bushings stay in the subframe, you can revert back to the old stock bushings at any time if you decide to move to a different 4th gen.

The Aluminum 300zx collars have a narrower opening than the earlier delrin versions that some of us may still be running. The aluminum versions slide below and around the old bushings during installation. This requires the installer to press down on the subframe (using a pry bar as shown in a picture above) to lower it enough so the C collar opening can clear the old rubber mount.

So this mod requires a bit more muscle to install the aluminum upper C collars than the old versions, but the payback from the smaller C opening will prevent the collars from falling out on the street should the lower bushing become loose after years of use.

Also note that if you already have the older delrin versions, and the upper C collars have fallen out or you still have some subframe slop to tighten up, you can use the old lower delrin spacers on the front post instead of the Titan truck delrin spacers. In that case you only need to buy the Aluminum 300zx C collars, the Perrin bushing and possibly a Fastenal washer. The Fastenal washer would only be needed if you want to give the lower front bushing a little more support. I chose the Fastenal washer to give the Titan truck delrin bushing some extra strength so I won't need to touch it again for a very long time.

I actually had one 4th gen running with a hybrid mix of the old delrin front lower with the Aluminum 300zx uppers and the Perrin rear bushing while prototyping this mod. So there may be some members with the old delrins that are looking to upgrade.

Because I wanted to make this a mod that anybody could replicate, I bought the Titan delrin bushings and learned those could be used after being bored out to fit over the old rubber subframe bushing.

The mod is working great on two 4th gens that are daily drivers for my son and daughter.

Update: My youngest son just installed G35 front brakes on the 99 SE. I'm hoping he will post a write-up. It has BRAKES now.

dual piston right? sounds kool

That's right with larger rotors.

After 5,000+ miles of use on the 99 model SE, here are a couple of pictures to check on on how the bushings are holding up. So far so good.

Rear

Attachment 11742

Front

Attachment 11743

wonder if this will work on a 2001 . Should be the same:confused:

I would try to find the original delrin FS threads and compare the 4th and 5th gen pics! But there's really only one way to find out! :D

I've always wondered if there was supposed to be a thickness difference between the 4th and 5th gen. Also were the front and rear Delrin spacers for the 5th gen the same thickness?

I may be wrong, but I always thought I ended up with 5th gen Delrin spacers by mistake. They just seemed too small from day one. Though, another person that bought the 4th gen Delrin had one fall out as well. I bought that person's set and found out later that it was missing a collar. When I asked about it, they said they lost it somewhere.

If somebody already has a set of the old Delrin spacers and they are looking to upgrade, they can use the old Delrin lower front spacer with the aluminum c-collars as uppers. They might also be able to use the old Delrin rear lower with the aluminum upper c-collar. I didn't try that using the old Delrin for the rear. However, I did try it for the front with the Fastenal washer and it worked.

So if you have a set of the old Delrin spacers, and you have lost one of the uppers, you might try the aluminum c-collars as replacements.

I've seen pictures of cars where industrial washers were cutout to the size of the c-collars. I thought about that but didn't want the whole thing to completely metal-to-metal especially for the rear.

I'll post pictures at 5,000 mile increments to show how this holds up.

Please note that the cars where I have this running have no rust damage or exposure to road salt. They also have new LCAs, struts, end links, and bushings. So this was the last thing I felt like I needed to do on that suspension project. But I can't begin to think about how this would feel or work with other body or suspension wear variables.

Here's a link to the original 5th gen thread.

https://maxima.org/forums/group-deal...e-collars.html

And the link to the 4th gen thread.

https://maxima.org/forums/4th-genera...e-collars.html

Over a year later and we're in July of 2018. The spacers are still working.

http://i286.photobucket.com/albums/l...r_Subframe.jpg

http://i286.photobucket.com/albums/l...r_Subframe.jpg

How about a July 2019 update with pics?

I bought everything to do this. I just don't quite have a reason to yet. My factory subframe bushings look and feel fantastic! I can't imagine the ride being much better with this mod, yet...

Here's a July 2019 update for the 99 model. My daughter has the 98 out on the road today.

My how time flies when you're having fun.

Let's make sure the expectation of ride is for tighter and more responsive handling vs. a new Cadillac ride. It brings our A32 closer to a tight and responsive sports car feel. I learned about this type of mod from the Nissan Z32, s-chassis (S13/S14), and Subaru WRX worlds.

Pardon the mud, dirt and road tar. This car is NOT a garage queen.

Left Front

https://i286.photobucket.com/albums/...Left_Front.jpg

Right Front

https://i286.photobucket.com/albums/...ight_Front.jpg

Left Rear

https://i286.photobucket.com/albums/...Right_Rear.jpg

Right Rear

https://i286.photobucket.com/albums/..._Left_Rear.jpg

Good stuff. I'll have to do this on my second 4th gen.

Posting the last update for 2019. All is well. I couldn't go back to a stock suspension now if I wanted.

https://i286.photobucket.com/albums/...frame_Pic2.jpg

https://i286.photobucket.com/albums/...frame_Pic3.jpg

That's just great! This really is a good thread. Thank you for your contribution, CS AR!

Great, thorough writeup! This should definitely be a sticky...if it isn't already. Have you PM'd a moderator?

I think the sticky section stopped being updated years ago. So many pictures no longer work.

Did you have to do anything on your SE to get the triangular braces to work with the subframe spacers? I had to add a bunch of washers to get them on with the spacers (this is many years ago, but still true today):

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

I wanted to re-seat my two front upper spacers as they weren't fully seated (needed to be hammered in a bit):

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

But when I got in there I noticed that two spacers in the front had started for form some cracks (after 10+ years of use):

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

So now I think I'm just going to replace all of them with the ones you use as there's no point in trying to fix something that's halfway broken. But when I went to test the removal of the nuts for the front studs, I couldn't get any tools in there. The access hole in the Moog control arms didn't line up:

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

And the control arms are too close to the stud to get any sockets in there:

https://images.squarespace-cdn.com/c...e=image%2Fjpeg

I'm guessing that's due to the coilovers not having as much droop travel as stock style struts. It looks like the easiest way to get access would be to pop the ball joint off the knuckle to allow the control arm to droop down further. What do you think?

It looks like your links for 300zx spacers on Ebay don't work anymore, are these the same ones? They look a little different than the ones you have pictured.

And in case anyone else was wondering, here's what the FSM says about torque specs. 107 ft-lbs for the front and rear nuts, and 33 ft-lbs for the two bolts for the SE triangular braces.

https://images.squarespace-cdn.com/c...pe=image%2Fpng

I didn't use any washers on my 97SE for that triangle bracket.
I would try using a wobble extension to get that subframe nut.

Interesting, does the triangle bracket actually sit flush like it did before the spacer install, or is it cocked at an angle? Looking at my car I can't see how the bracket could sit the way it normally does without washers in place.

Good idea on the wobble, I often forget I have those things :smash:

By coincidence, on 9/7 I was at a junkyard trying to find a steel wheel with minimal runout. Probably because of the heat and smoke, I came out with no wheel, but with 2 of the triangular brackets.
I started installing them and could not remember if the GXE part stacked with the bracket, so I came back in the house ready to pop the question :), fortunately Craig's thread answered it. Probably will make no difference, but I had enough of staring at monitors... Taking it out for a test drive in a bit as my 5y old wants to check "her" work.

edit: Drove it, placebo wants to make me think the steering wheel wobbles less on broken pavement, while transmitting more shock to the body.

The area around the subframe is slightly cocked.
https://cimg5.ibsrv.net/gimg/maxima....2c8f11a661.jpg

Or use one of those short sockets that snap in, not onto, a ratchet. The kind where bolts can pass completely through. Now you have an excuse to go out and buy more tools. :D

Oh, pass through sockets? I have those too, and always forget about them because of how infrequently I use them! I guess my big concern is being able to apply the correct amount of torque when reassembling everything, but I may be able to do that with a wobble bit like Leonard mentioned.

I ended up buying this set of 300zx aluminum spacers since the pictures more closely resembled the original pics CS_AR posted.

In case anyone is interested, I installed these onto my car, with some necessary modifications. Pics and info are in my build thread.

Hi, i already build this spacer. I used polyurethane with 90SH
https://cimg2.ibsrv.net/gimg/maxima....846f39e635.jpg

Final thickness 18mm..now i just wait 300zx alumunium spacer for the rear upper and front upper..
https://cimg2.ibsrv.net/gimg/maxima....7fc868ba55.jpg
Still need alumunium spacer.. I built this from polyurethane 90SH..

Very cool! I wish I had a lathe like that I could play with.