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few questions about the handling characteristics by RudyGT
Started on: 12-01-2018 09:03 PM
Replies: 10 (173 views)
Last post by: msweldon on 12-02-2018 03:20 PM
RudyGT
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Report this Post12-01-2018 09:03 PM Click Here to See the Profile for RudyGTSend a Private Message to RudyGTEdit/Delete MessageReply w/QuoteDirect Link to This Post

hello again, 88 formula here, stock components
so there's a few round-a-bouts 'round here, and i've noticed when i am taking them fast while accelerating or maintaining gas
(i dont recall ever NOT being on the throttle through a turn) it seems the car anti-squats on all 4 wheels, like the car is lifting up in the air. normal?
is this called something? am i doing something wrong?

and im assuming the fiero also is very susceptible to wind as i can travel the same road at different times, same speed,
and its smooth as can be, others im pushed all over but i don't hear wind buffeting so im not sure.. i only hear WWOOOOOOOOOUUUO
and a little music that over powers the engine sound

also is it normal that since it's not power steering any grade difference and deep bumps will grab the car and take it where it wants?

and lastly that i can think of that has been on my mind is, at speeds around 80+, the front end feels really light, the car doesnt seem planted.
Quickly giving inputs to the steering wheel results in a floating feel, and actually feeling the delay for the rear wheels to line up with the front,
is this because the whole front hood is positively filled with air?
i heard cutting a scoop would let the air pass through and fix this issue, is this correct or is there other known solutions?
anyone know how that affects the drag co-efficient?

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Gall757
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Report this Post12-01-2018 09:54 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

I think you have some worn out components in your suspension......perhaps bad tires, shocks, or bad wheel bearings. There may be some alignment issues too. I say this because I have a Formula that I have pushed around a little bit and it feels really solid except for that front end float issue......but I've only noticed that at about 100 mph.

edit: bumps in the road moving the car around is not normal. Something is loose.

[This message has been edited by Gall757 (edited 12-01-2018).]

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La fiera
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Report this Post12-01-2018 10:11 PM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post

Replace your steering damper. Front end will float past 100 mph, thats normal. And yes, if you can make a hood vent to release air pressure off from under the front bonnet it will alleviate that problem. My Fiero was doing the same thing and I installed a front splitter and a hood vent and at 140mph on the banks of my local speedway the car felt very steady and firm.

https://youtu.be/Ps9PgmKFuNw

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msweldon
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Report this Post12-02-2018 01:40 AM Click Here to See the Profile for msweldonClick Here to Email msweldonSend a Private Message to msweldonEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by La fiera:

Replace your steering damper. Front end will float past 100 mph, thats normal. And yes, if you can make a hood vent to release air pressure off from under the front bonnet it will alleviate that problem. My Fiero was doing the same thing and I installed a front splitter and a hood vent and at 140mph on the banks of my local speedway the car felt very steady and firm.

https://youtu.be/Ps9PgmKFuNw


No steering damper on an 88.

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fieroguru
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Report this Post12-02-2018 11:01 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post

Worn suspension bushings, rack bushing, too little caster, loose long bolt in the rear, bad tires, wheel bearings or struts.

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La fiera
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Report this Post12-02-2018 11:09 AM Click Here to See the Profile for La fieraSend a Private Message to La fieraEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by msweldon:


No steering damper on an 88.


Thanks for the correction Weldon!

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msweldon
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Report this Post12-02-2018 11:27 AM Click Here to See the Profile for msweldonClick Here to Email msweldonSend a Private Message to msweldonEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by La fiera:


Thanks for the correction Weldon!


NP

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msweldon
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Report this Post12-02-2018 11:44 AM Click Here to See the Profile for msweldonClick Here to Email msweldonSend a Private Message to msweldonEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by fieroguru:

Worn suspension bushings, rack bushing, too little caster, loose long bolt in the rear, bad tires, wheel bearings or struts.


What he said X2

I obtained a 150K mile 88 GT that was kept in near immaculate shape, all original, and was and still impressed of how relatively stable a ride it is at the limit, during transitions, etc... and still maintain a comparatively comfortable ride. At autocross speeds, it can still surprisingly 4 wheel drift through a wet corner at a neutral throttle and the rear tucks in nicely under braking "as" you "start" to transition into oversteer.


The roaring sound you are hearing is most probably a wheel bearing.

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RudyGT
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Report this Post12-02-2018 12:38 PM Click Here to See the Profile for RudyGTSend a Private Message to RudyGTEdit/Delete MessageReply w/QuoteDirect Link to This Post

 
quote
Originally posted by msweldon:
The roaring sound you are hearing is most probably a wheel bearing.

wheel bearings would get hot if bad right? i'll check them if so, the roaring sound i referred to though is most definitely the engine.
anything above 60mph in 5th gear and its loud, except maybe 85+ it no longer resonates as bad.

i'll look up how to visually inspect components, i did mean deep bumps, the steering wheel reacts to these things as well.
if the car is affected by the road i feel it in the wheel, also i feel pretty much everything with my body, but this is comming from a more cushioned ride.

im putting the car back up on 3 foot jack stands to get back under and patch the exhaust near the cat so i'll take a look at everything.
i do have new bright red poly bushings on the anti-sway bars front and back. grease has covered one of the tie rods in the front right i think, its a tie rod

as it is now i only know motorcycle and mountain bike suspension so, i understand the concept and why its stiff but, things like control arms..
i get that they try to remove camber as the tire goes up and down but how thats done i gotta read up on along with steering being tied into 2 wheels.

thanks for the help guys, but does the anti squat thing in corners make any sense to anyone? specially in rally cross?
we're talking like 35-40mph decreasing radius turns where the entire car seems to lift, is this just physics because of centripetal force?

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Gall757
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Report this Post12-02-2018 12:59 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post

There are a lot of Fiero gatherings in Florida. Keep an eye open for one and take your car. That would be a quick way to diagnose. Fieros don't 'squat' much, so I am thinking you should contemplate new shock absorbers first. Loose wheel bearings may not heat up, but they sure can make the car squirrilly...

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msweldon
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Report this Post12-02-2018 03:20 PM Click Here to See the Profile for msweldonClick Here to Email msweldonSend a Private Message to msweldonEdit/Delete MessageReply w/QuoteDirect Link to This Post

Do you hear the roar more when you load up one side of the suspension? Still not convinced it's not bearings. Jack up the car and do a 3/9 o'clock and 12/6 o'clock manual test on the bearing with the wheel attached to look for any movement

Luckily the 88 subframe is solid mounted to the chassis unlike the pre 88s so no worry there. Do inspect your struts, if they are OEM originals or 20 year old after markets they're probably toast.

Simply put, the front unequal length wishbone / suspension design is intended to increase 'negative' camber on the outside wheels of a turn and increase positive camber on the inside wheels of a turn in relation to the amount of chassis roll. There's more to it than that but that's the basic premise.

The rear multilink / McPherson setup does the same, just not as well and only for a limited range of motion, if lowered or lowered by sagging 30 yr old oem springs, the rear camber under load can go from negative camber "good" to positive camber "bad" which might explain 'some' of the squirrelyness as the suspension compresses. Look at the rear suspension while on flat ground, if the control arm links that go out perpendicular to the chassis to the upright are not parallel to the ground and are pointing up you have some sag and some positive camber under load.


the 88 fiero is rear biased obviously and being both under-sprung and under-tired from the factory to maintain a smooth ride and fuel economy it's butt will lag a bit behind the rear.

[This message has been edited by msweldon (edited 12-02-2018).]

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