Pennock's Fiero Forum
  Technical Discussion & Questions
  Does flipping over the strut top mounting plate change the Fiero's rear height? (Page 2)

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version

This topic is 2 pages long:  1   2 
Previous Page | Next Page
next newest topic | next oldest topic
Does flipping over the strut top mounting plate change the Fiero's rear height? by Patrick
Started on: 11-21-2013 02:17 AM
Replies: 56 (3197 views)
Last post by: Spadesluck on 11-12-2023 06:11 PM
fieroguru
Member
Posts: 12336
From: Champaign, IL
Registered: Aug 2003


Feedback score:    (45)
Leave feedback





Total ratings: 259
Rate this member

Report this Post01-29-2022 09:25 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

When flipping the strut plate, the bottom surface of the bump stop moves up as well.

Does this create the potential for the tire to hit/rub the plastic wheel well liner, or perhaps other issues? 84-87 toe-link hitting the frame rail? My Fiero is covered in snow; can't look now.


Tire rubbing is largely dependent diameter and width of tire and offset of wheel. If the wheel/tire combo is close to stock, tires should not nub. Wider/taller tires likely will. This is less of an issue with the 88's as the 88 knuckle is taller (from wheel center), so you reach the end of strut travel with the wheel further from the underside

Tie tie rod link will likely interfere with the frame rail. On page 18 of Will's thread he cycles his 84-87 suspension to full compression w/o any springs or bump stops and the strut hat in stock orientation, the tire rod is about 1/8 from the frame. The flange and rail could be trimmed slightly for additional clearance.
IP: Logged
pmbrunelle
Member
Posts: 4510
From: Grand-Mère, Québec
Registered: Sep 2008


Feedback score: N/A
Leave feedback





Total ratings: 63
Rate this member

Report this Post01-29-2022 09:46 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroguru:
Tie tie rod link will likely interfere with the frame rail. On page 18 of Will's thread he cycles his 84-87 suspension to full compression w/o any springs or bump stops and the strut hat in stock orientation, the tire rod is about 1/8 from the frame. The flange and rail could be trimmed slightly for additional clearance.


That's good info, thanks for finding it.

Flipping a KYB strut plate will move the strut rod up by ~1.050".

Probably with the right bumpstop the toe link can be kept far enough away from the frame rail notch.

I suppose that without a spring, if the rear of the car is jacked up via the knuckle (the entire rear end weight squishing one bumpstop) that would represent a worst-case bumpstop squish.

[This message has been edited by pmbrunelle (edited 01-29-2022).]

IP: Logged
fieroguru
Member
Posts: 12336
From: Champaign, IL
Registered: Aug 2003


Feedback score:    (45)
Leave feedback





Total ratings: 259
Rate this member

Report this Post01-30-2022 09:30 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
With the sway bar disconnected (if you have one) and no spring, it is quite easy to cycle to the suspension to full compression. While it is there, you might as well put the trans in neutral and spin the wheels by hand to check for Tripot binding. As you maximize the limits of suspension travel, tripot clearance becomes more important to check. Especially if you like to lower the drivetrain as low as possible in the chassis.
IP: Logged
wilberto
Member
Posts: 72
From: park city, utah
Registered: Apr 2021


Feedback score: N/A
Leave feedback

Rate this member

Report this Post01-30-2022 12:21 PM Click Here to See the Profile for wilbertoSend a Private Message to wilbertoEdit/Delete MessageReply w/QuoteDirect Link to This Post
I did a complete new suspension on my 85 GT, rebodied as a 308. Bushings, rear struts, shocks and Eibach springs. I flipped the strut towers before installing new springs and it lowered my rear suspension about .5" I do have more travel as well, no bottoming out. The springs are what lowered it the most. I also installed 2" wheel spacers in front and 2 3/8" wheel spacers in the rear to give it the proper stance. I wasn't thinking about handling when I did the wheel spacers but...WOW. Unbelievable handling, like a rally car, Very tight and responsive.
IP: Logged
Patrick
Member
Posts: 37857
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post01-30-2022 04:03 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by wilberto:

I flipped the strut towers before installing new springs and it lowered my rear suspension about .5"... The springs are what lowered it the most.


For clarification... it was just the new springs that lowered your suspension. Flipping over the top mounting plates played no part in lowering the suspension.

 
quote
Originally posted by wilberto:

I also installed 2" wheel spacers in front and 2 3/8" wheel spacers in the rear to give it the proper stance.


It's possible that using spacers of that thickness contributes to lowering the car as well, as the wheels being pushed out by that distance changes suspension geometry, leverage on the springs etc. Maybe fieroguru could comment on this.

[This message has been edited by Patrick (edited 01-30-2022).]

IP: Logged
wilberto
Member
Posts: 72
From: park city, utah
Registered: Apr 2021


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-02-2022 08:43 AM Click Here to See the Profile for wilbertoSend a Private Message to wilbertoEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you read my post, I said I flipped the strut towers before installing the springs and it lowered the car by .5". I can't be more clear on that.
IP: Logged
Will
Member
Posts: 14252
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 237
Rate this member

Report this Post02-02-2022 09:27 AM Click Here to See the Profile for WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroguru:

Tire rubbing is largely dependent diameter and width of tire and offset of wheel. If the wheel/tire combo is close to stock, tires should not nub. Wider/taller tires likely will. This is less of an issue with the 88's as the 88 knuckle is taller (from wheel center), so you reach the end of strut travel with the wheel further from the underside

Tie tie rod link will likely interfere with the frame rail. On page 18 of Will's thread he cycles his 84-87 suspension to full compression w/o any springs or bump stops and the strut hat in stock orientation, the tire rod is about 1/8 from the frame. The flange and rail could be trimmed slightly for additional clearance.


https://www.fiero.nl/forum/.../000121-21.html#p817

Bump stop removed; measurements taken at metal-to-metal contact between the gland nut of the Koni strut and the dished washer underneath the strut top mount.
Tire pictured is 285/30-18 on a C5 Corvette 18x9.5 Conestoga (61mm offset) with a 1" spacer/adapter.

Flipping the top mount and installing a bump stop would result in a bit more wheel travel possible, but the tire would definitely rub the fender on large excursions.

IP: Logged
jjd2296
Member
Posts: 1453
From: toronto ON
Registered: Jan 2016


Feedback score:    (8)
Leave feedback

Rate this member

Report this Post02-02-2022 12:18 PM Click Here to See the Profile for jjd2296Send a Private Message to jjd2296Edit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure if this was previously mentioned, but why not just install the tie rod end to the bottom of the knuckle rather than on the top to compensate for the additional height as a result of the kyb strut plate being upside-down?

[This message has been edited by jjd2296 (edited 02-02-2022).]

IP: Logged
pmbrunelle
Member
Posts: 4510
From: Grand-Mère, Québec
Registered: Sep 2008


Feedback score: N/A
Leave feedback





Total ratings: 63
Rate this member

Report this Post02-02-2022 01:11 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Will:
Flipping the top mount and installing a bump stop would result in a bit more wheel travel possible, but the tire would definitely rub the fender on large excursions.


Assuming I install the spring with the same preload (1/4") in both cases (standard/flipped), the coilover assembly will provide exactly the same compression/droop travel relative to the resting position.

So the main difference between standard/flipped would be a ~1" difference in ride height.

Standard:
Car CG a bit higher, less risk of rubbing things

Flipped:
Car CG a bit lower, more risk of rubbing things

Next spring/summer I will check which alternative I prefer by cycling the suspension with my tire of choice.

My main focus is to make my Fiero easy to drive / predictable, while not having the highest limits. If I lose a bit of grip because its CG is higher, I won't cry over that.
IP: Logged
Will
Member
Posts: 14252
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 237
Rate this member

Report this Post02-02-2022 01:41 PM Click Here to See the Profile for WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by jjd2296:

Not sure if this was previously mentioned, but why not just install the tie rod end to the bottom of the knuckle rather than on the top to compensate for the additional height as a result of the kyb strut plate being upside-down?



That would require using a tapered reamer to cut the correct taper into the knuckle and would create large amounts of bump steer.
IP: Logged
Will
Member
Posts: 14252
From: Where you least expect me
Registered: Jun 2000


Feedback score: (1)
Leave feedback





Total ratings: 237
Rate this member

Report this Post02-02-2022 01:47 PM Click Here to See the Profile for WillSend a Private Message to WillEdit/Delete MessageReply w/QuoteDirect Link to This Post

Will

14252 posts
Member since Jun 2000
 
quote
Originally posted by pmbrunelle:

Assuming I install the spring with the same preload (1/4") in both cases (standard/flipped), the coilover assembly will provide exactly the same compression/droop travel relative to the resting position.

So the main difference between standard/flipped would be a ~1" difference in ride height.

Standard:
Car CG a bit higher, less risk of rubbing things

Flipped:
Car CG a bit lower, more risk of rubbing things

Next spring/summer I will check which alternative I prefer by cycling the suspension with my tire of choice.

My main focus is to make my Fiero easy to drive / predictable, while not having the highest limits. If I lose a bit of grip because its CG is higher, I won't cry over that.


If you moved the lower perch to maintain pre-load, then yes, that would change ride height.

Without moving the lower perch, there's no change in ride height.

At the higher ride height, the Fiero suspension has a higher roll center. '88's actually like this. Lowering the car lowers the roll center more than the car is lowered, so even though the CG is lower, the roll moment ends up HIGHER due to longer lever arm from CG to roll center.

[This message has been edited by Will (edited 02-03-2022).]

IP: Logged
PFF
System Bot
Patrick
Member
Posts: 37857
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post02-02-2022 03:35 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by wilberto:

If you read my post, I said I flipped the strut towers before installing the springs and it lowered the car by .5". I can't be more clear on that.


I read your post. What exactly are you referring to... "strut towers"...? You and I might be using different terminology. What did you actually flip?
IP: Logged
wilberto
Member
Posts: 72
From: park city, utah
Registered: Apr 2021


Feedback score: N/A
Leave feedback

Rate this member

Report this Post02-05-2022 03:45 PM Click Here to See the Profile for wilbertoSend a Private Message to wilbertoEdit/Delete MessageReply w/QuoteDirect Link to This Post
I just flipped the hats. I've read numerous articles on this subject...some people say it lowers the vehicle, some say it doesn't. I've got it where I want it so that's fine with me. We may be using different terminology for the same part, that can vary from manual to manual.
IP: Logged
Patrick
Member
Posts: 37857
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post02-05-2022 10:17 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by wilberto:

I just flipped the hats. I've read numerous articles on this subject...some people say it lowers the vehicle, some say it doesn't.


It doesn't.

 
quote
Originally posted by wilberto:

I've got it where I want it so that's fine with me.


I'm glad you got it where you want it, but it wasn't from flipping the hats.

Wilberto, the whole reason why I started this thread nine years ago was because of all the erroneous information that was floating around online about this simple mod. I felt there needed to be a thread at PFF where this was set straight once and for all. I have to admit I'm rather surprised that after all that's been posted in this thread, that there still appears to be some confusion. Several contributors to this thread, some much more knowledgeable than myself, have all agreed and stated quite clearly that flipping over the hats does not affect ride height at all. It is what it is.
IP: Logged
87GT3800SC5SPD
Member
Posts: 309
From: Gig Harbor, Washington
Registered: Oct 2002


Feedback score: N/A
Leave feedback

Rate this member

Report this Post11-12-2023 05:21 PM Click Here to See the Profile for 87GT3800SC5SPDSend a Private Message to 87GT3800SC5SPDEdit/Delete MessageReply w/QuoteDirect Link to This Post
I haven't visited the forum since sometime before this discussion began in 2013. It is nice to return and see that these kind of discussions are still going on.

My Fiero has been lowered three times in the past 26 years of ownership. The last time, it received 2" drop spindles in the front, 4 OMG firm springs and adjustable coil overs in the rear.

The final adjustment, after ride height was determined, was to reverse the top hat in the rear for the purpose of slightly increasing rear suspension travel. That change required the previously mentioned, small modification in the vents that is hardly noticeable. When the ride is similar to a shifter cart, you appreciate an additional .5" in suspension travel.

I can also verify that occasionally, an unexpected dip in the road will cause tires to contact the fender well liners. Those rub marks help identify where the liners need to be modified.

IP: Logged
Patrick
Member
Posts: 37857
From: Vancouver, British Columbia, Canada
Registered: Apr 99


Feedback score: (1)
Leave feedback





Total ratings: 464
Rate this member

Report this Post11-12-2023 05:43 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 87GT3800SC5SPD:

I haven't visited the forum since sometime before this discussion began in 2013. It is nice to return and see that these kind of discussions are still going on.


Welcome back... but aw man, another thread with missing images. I'll have to see if I can locate my missing images to re-post.
IP: Logged
Spadesluck
Member
Posts: 2147
From: Georgia
Registered: Jul 2016


Feedback score:    (8)
Leave feedback

Rate this member

Report this Post11-12-2023 06:11 PM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
On a stock height Fiero, I would say no unless you are jumping the car. Now, on a lowered car hitting the inner liner is always an issue depending on the ride height.

With my 87 lowered with coil overs in the back I never had an issues with toe or hitting liner. The front is another issue as there isn't as much tuck room.
IP: Logged
Previous Page | Next Page

This topic is 2 pages long:  1   2 
next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock