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Balance isn't mythical. A vehicle whose center of gravity and center of pressure for the aero are not aligned will suffer drastic handling changes depending on speed. Not ideal. And a spoiler is designed to spoil airflow to prevent lift. On a car it is usually employed to prevent air from flowing around (usually under) the car and lifting it at higher speeds. An airfoil generates lift (downforce if mounted upside down obviously).
 

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Balance isn't mythical. A vehicle whose center of gravity and center of pressure for the aero are not aligned will suffer drastic handling changes depending on speed. Not ideal. And a spoiler is designed to spoil airflow to prevent lift. On a car it is usually employed to prevent air from flowing around (usually under) the car and lifting it at higher speeds. An airfoil generates lift (downforce if mounted upside down obviously).

My point being that it WORKS on a light road car like the ZZW30. Any arguments about upsetting balance support this.
Whether the effect is as one wants it or not is a totally different issue.
Point is that aero works at cycling speed! See the one inch strip and legal highway speed stability increase, which also affects the ´balance´ by the way ;)

And centre of gravity.... that is a bit dfferent. Aero is weightless, ´just´ a force possibly creating a moment around the axle of turning which in this case can be taken as the rear wheels.
A rear wing, air foil, spoiler, means weightless extra traction of the rear tyres. This at no negating cost of extra centrifugal force through corners.
Yes it changes balance by changing, reducing, the drift angle of the rear tyres as cornering speed increases.
It does nothing to weight balance or moment of inertia.
To put the effect in perspective a quite large and effective rear wing increases the road on the rear axle with say 500N at 120 km/h. The weight of the car at the rear is some 6.000N....
Now have a look at the spring rates in the table: The ratio of OEM and after market vs the TRD ratio has a larger effect on how the rear suspension speeds up in relation to the front. Yet this seems to pass universally unnoticed.
Bottom line; balance is all relative :cool:

And please note that extra traction at the rear because of aero does not give you any less at the front.
You can also rephrase it into it reducing the snap of oversteer resulting from too much throttle or lifting it.
So, you balance the pros and cons 🤪

And regardless; we apparently all agree that it works (y)
 

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A wing provides downforce. A spoiler interrupts airflow for the purpose of controlling turbulence. That is the origin of the name "spoiler." A spoiler on the rear deck is usually to reduce drag. A spoiler in a different location is probably very specific to the airflow at that point. A fairing or air dam is just supposed to exclude the airflow from a certain space.
If you insist on semantics than you are wrong.
A wing is an air foil. As a wíng the effect is creating líft. On a car it is uses as an inverted wing.

Whether upwards or downwards in effect, tt does so by interfering with.... air flow.

A spoiler on the rear deck, well. again, no, not that simple. How would you call a one inch rubber lip to create a tear off ridge for the flow?
Or what about the Gurney flap?

And ´fairing or air dam´.... Are those not too two different things? Not quite interchangeable words in mý aero dictionary.

Point being that you are using semantics as you see fit, totally confusing the issue.
I don´t care what tag you want to stick on which aero attribute. Even the flip up thingy behind the seats and mongos are ´spoilers´ of sort, changing the turbulence .... In mý dictionary is simply is all aero aids.

On mý car I have the OEM ´dams´ in front of the front wheels, added a chin lip, removed the spare wheel well, added bonnet (hood) vents, created some rake, have mongos, removed the undertrays at the rear, increased air flow through the engine bay, removed the rear heat shield opening up the rear exit, mounted an inverted wing, stuck a lip at the rear.... Ah and have a tonneau tarp which at one time was all but obligatory for spyders at LeMans 24H.
By all means you class the aero mods as dams, fairings, spoilers, flaps or whatever as you see fit.

Btw. a bloke on the UK forum did a nice before and after of the turbulence behind the front wheels of OEM mudguards. Quite effective spoilers ;)
 

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Discussion Starter · #64 · (Edited)
Any chance you have a picture of it installed?
Automotive parking light Tire Wheel Car Vehicle


All installed. Had the oil changed yesterday and the mechanic I see likes my car so he installed the chin spoiler for $70. Since I'm 71 I don't care for getting on the floor with bulging discs and all. Mech said that he had to drill into the bumper, which I approved, since there was nowhere to bolt in the part. Upon research, he claimed that the chin spoiler was not offered as an option until 2002 (mine's a 2001).


Also, I'm assuming that to the right on the following picture, this is one (I have both) of the "spats" that OldMan mentioned earlier in this thread:

Automotive parking light Tire Wheel Vehicle Automotive lighting


Several SpyderChat members have posted about engine lid mounted luggage racks, but I'm not one of them. I rarely carry any cargo other than a coat stored in the cubby behind the seats and a small "survival kit" in the frunk.

On this thread's original topic:
All Spyders came with rectangular "spats" in front of the front wheels. They add stability and should not be removed, but owners have been known to remove them anyway. If yours are missing, replace them. Here is a low resolution image (best I could find) of a 2000 ad extolling them.
We're dealing with remnants of Ian in southern New England, a first world problem compared with my friends in the South, so I won't test this out until Thursday. Between the Spyder, hockey, Amateur Radio License test in two weeks, studying Russian (изучать русский язык) one of my jobs in the Army, wife, sons, and Leukemia follow-ups (clean for now) I'm staying busy and I'd like to thank everyone here for their guidance, advice, and patience.

My car... well needs just a wee bit more rake still. Who needs top speed on the public road anyway?
I do. I'm just very judicious about it. Plus you don't know when you need to rob a bank. God bless 'murica. :cool:
 

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Discussion Starter · #66 ·
Correct.

Since you ´test´ at speed; have you noticed an effect?
Marginal at best. It hasn't gotten worse, but I really haven't driven the car at high speed all that much lately. Car felt fine at 90mph last week. I am considering putting 215's in the back and 205's in the front but that'll be next year (I know there's a thread on Spyderchat with someone putting 215 and 205 on the OEM 6.5" and 6" rims; need to research that again). Will most likely get a Moroso oil pan first. I'll keep this car for the long haul and I still enjoy going for pleasant drives with the wife. Cheers
 

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Marginal at best. It hasn't gotten worse, but I really haven't driven the car at high speed all that much lately. Car felt fine at 90mph last week. I am considering putting 215's in the back and 205's in the front but that'll be next year (I know there's a thread on Spyderchat with someone putting 215 and 205 on the OEM 6.5" and 6" rims; need to research that again). Will most likely get a Moroso oil pan first. I'll keep this car for the long haul and I still enjoy going for pleasant drives with the wife. Cheers
Did you mean 215/45r16 in the rear? I don't think anyone makes a 215 tire for 15 wheels. 225 yes, but 7 inch wheels are required. You said earlier that you had S-Drives at one time, how did they compare at 90+ to your current PA31s ?
You could always get a splitter for the front for serious high speed driving.
 

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A better car, of course. More specifically, higher straight line speed while not sacrificing safety. I realize this is a difficult combination.
Not that obvious, the more because wider tyres do not contribute to your goal.
Furthermore a higher top speed does not make a better car.
Lastly higher speed is per definition more risk. No way around that.

The pfl OEM size is pretty much the ideal for road use. Even pretty extreme, illegal speed, road use.
If you want it safe, simply buy the bést tyre for your purpose.

If (perceived) stability is your issue, then fit the toolkit in with the jack and spare tyre.
More weight further up front increases the moment of inertia (MR2). Some even add some ballast weight.
 

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Discussion Starter · #71 ·
Did you mean 215/45r16 in the rear? I don't think anyone makes a 215 tire for 15 wheels. 225 yes, but 7 inch wheels are required. You said earlier that you had S-Drives at one time, how did they compare at 90+ to your current PA31s ?
You could always get a splitter for the front for serious high speed driving.
I found these on tirerack:

VREDESTEIN
SPRINT +
Grand Touring Summer
  • Size: 215/50R15 88W
  • Style: Blackwall
PIRELLI
P700-Z (COLLEZIONE)
High Performance Summer
  • Size: 215/50ZR15 88Y
  • AO Audi, Pirelli Classic Tire
  • Style: Blackwall
Expensive for my tastes, but I'd like to find out if they'd fit on my OEM rims.
 

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Discussion Starter · #72 ·
Not that obvious, the more because wider tyres do not contribute to your goal.
Furthermore a higher top speed does not make a better car.
Lastly higher speed is per definition more risk. No way around that.

The pfl OEM size is pretty much the ideal for road use. Even pretty extreme, illegal speed, road use.
If you want it safe, simply buy the bést tyre for your purpose.

If (perceived) stability is your issue, then fit the toolkit in with the jack and spare tyre.
More weight further up front increases the moment of inertia (MR2). Some even add some ballast weight.
What a "better" car is debatable. If you want more speed than the other driver, then more speed is better. There's a nice stretch of interstate south of me in NE Connecticut that is sparsely patrolled during daylight hours. But yeah, your point of better tires is well made and well taken. My carppy PA31 Ecsta's most likely are not worthy of speed. They used to be worth it for 20k miles at around 85 dollar, now not so much I do wish they still made the s-drives; they were a nice tire, but, I had the 1ZZ back then. Now with the 2ZZ I know the car has much more potential. Really don't know which way I want to go, especially with this place, Thompson Speedway – Full Speed Ahead , right down the road from my location.

It has been mentioned in this thread that wider tires produce a more stable drive. Do you disagree with this premise? I like the idea of more ballast. I do, however, have an OEM jack/ttoolkit stored behind the passenger. Not trying to be disagreeable; just trying to weigh all the data/factors before I spend money. Cheers.
 

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It has been mentioned in this thread that wider tires produce a more stable drive. Do you disagree with this premise?
Well, the basic ´problem´ of ´instabiity´ is the low moment of inertia but as that is the whole reason for the concept of the MR2; heck it is even námed after it! the subject is a bit diffuse unless more specifically explained.
The ´instabilty´ makes it such a joy to flick through twisties.
It also means it needs less input for (apparent) change in direction when in a straight line at higher speed.

Wider tyres will indeed dull down the overall nimbleness of the car. So yes, also a bit at speed.

I took a lót of weight off the front end to make the car overall more nimble (less stable?) still and restored high speed stability with an already mentioned of aero.

Anyway, I´d stick with OEM pfl size, nót dumb the delightful car down and simply by the best in class tyre.
 

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I found these on tirerack:

VREDESTEIN
SPRINT +
Grand Touring Summer
  • Size: 215/50R15 88W
  • Style: Blackwall
PIRELLI
P700-Z (COLLEZIONE)
High Performance Summer
  • Size: 215/50ZR15 88Y
  • AO Audi, Pirelli Classic Tire
  • Style: Blackwall
Expensive for my tastes, but I'd like to find out if they'd fit on my OEM rims.
Both those tires would be nice but expensive tires for the back. I believe they fit best on 7 inch wheels. But I did not see a compatible front tire unless you mix brands.
What you can do and what you should do is all a matter of opinion. I agree with Petrus, stick with OEM sizes. If you want wider in the back go with the 2003-05 7 inch rear wheels. You can keep 6 inch in the front or put the 6.5's in the front. That little wheel "nib/tang" on the rear wheel can be unscrewed.
 
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