Directfreak

iTrader: (2)

I am sorry. I know Rice Racing is considered a Demi-God around these parts. However, I still don't beleive it.

I know there have been many improvements to power, technology, suspension in 20+ years.

You are saying that Rice racing has 600Hp or whatever, I doubt a stock bodied 1st gen could realistically survive it.

If the car is basically a plastic shell around a custom body, - basically not street legal - then that is a different car altogether.

Just like "funny" cars are nothing more than a resemblence to the production models.

I respect Rice Racing very much - can you provide different proof? I'd be happy to change my mind.

peejay

alrighty then. i'm still curious as to where you were on the tach. 140mph would be about 6500rpm with stock gearing and tires - and it'd be a healthy engine indeed (or a turbo) to make a minimum of 200 or so HP at only 6500.

revhed - i've never felt any instability in my RX-7s, ever. then again i set my alignment to somewhat bizarre (compared to norm) specs - the maximum negative camber I could get with the stock adjustment was +.5 degree, and I set toe to roughly -.5deg total. That's an awful lot of toe-out. The closer you set toe to zero, the more wandery it becomes at speed. There's a sweet spot between zero toe and extreme toe where a car will be the most stable, and after that as you go further with toe settings it gets worse, not better.

Also, wide low-profile tires are quite directionally unstable, because they lack self-aligning torque. Take off those spray-on tires and put on 185/70s and you will find the car transformed into a rock-stable beast at speed. (But good luck finding 185/70s with speed rating anymore!)

REVHED

Ratio box... it's a little gear box that goes in between your speedo cable and speedo drive.

peejay

You can also locate different-sized cable gears from Mazda. It's not as precise as a ratio box could be but it's cheaper. (Hey, it's good enough for manufacturers and gets you within 2% of perfect, right?)

Problem is, Mazda speedos are bad for slipping out of adjustment. The odometer will read accurately, but the speedometer will start reading too high.

MIKE-P-28

iTrader: (1)

Cuz when you change tire height you affect the number of times the tire has to turn to produce a given speed.

Pele

iTrader: (28)

I'm talking about my 1985 4wd wagon model with the 3 barrel carburetor. 6000 RPM redline.

That rear axle and differential add a bit of drag.

REVHED

*sigh* Rice Racing's car is a full stock bodied first gen devoid of body kit with suspension based on the stock design.

To reach these speeds he ran a 4.44:1 LSD and a 0.726:1 fifth gear.

This is a fully registered street car built for driving on the street and circuit racing.

Any more questions.

BTW, I have the full in-depth feature on this car in Zoom magazine right here in front of me.

peejay

I thought it was on-line too... I just spent about 1/2 hour or so searching for it but to no avail

Oh well, he'll probably be here sooner or later and set everybody straight

REVHED

Here's some pics of the car just for you Directfreak.

Directfreak

iTrader: (2)

Fair enough. I believe it.

I'll tell you this, ANYBODY who is willing to go over 160MPH (much less 200 Mph) on a stock bodied first Gen - HAS BIG *****.

Personally, I didn't think you could do it, without totally altering the aerodynamics of the first gen.

So...

I will shut up now.

MIKE-P-28

iTrader: (1)

And not only that but driving on the wrong side of the car Sorry I had to do it

peejay

On the Pantera mailing list I found some interesting info... they found that a significant high pressure area forms under the rear hatch.

I found the same effect in my RX-7 when driving at high speed with the windows open - the high pressure got under the rear carpet and it whipped forward and tried to wrap around my arms. Not a good thing to happen at 105mph.

The Pantera guys were talking about leaving the hatch open when driving at high speed. Over 140mph their hatch will "float" 6 inches up, and drag is reduced by eliminating a low-pressure area behind the car. The only potential problem with that is if the car spins, then the hatch would catch the air and whip open and all sorts of bad stuff would happen (even worse than merely spinning). So I was thinking, how about making a latch extension so that the hatch is fixed about 3-4 inches open? I'm willing to try it, and should not be difficult to do at all.

It reminds me of something I read about the RB LSR 3rd-gen (before it crashed), and how they were having aerodynamic problems - the air was not staying attached to the car and it was creating lots of turbulence and drag. They were experimenting with bleeding high-pressure air out of the cabin by altering the seals at the sunroof, which helped re-establish proper airflow over the rear of the car. (The reason the car crashed was simple - not enough traction - the saltbed is basically about as grippy as driving on snow. Back tires spin at 215mph, back end starts coming around, and at those speeds just about any shape can become a wing and get airborne)

REVHED

LOL!!

And Directfreak, there was a quote in the magazine article that the car is actually very stable at those speeds... as long as you don't lift off the throttle.

riffraff

i had that same thing happen in my 80.. doing high speed runs with the top off, and windows down.. suddenly i looked in my rear view mirror and everything was black. i was like what the ****... the wind completely picked up the rear carpet..

jeremy

iTrader: (1)

ok, why not roll up your windows and cut drag and lift?

"i turned my aluminum wing upside down i tried doing a highspeed run and the rearend lifted off the ground? i don't know why." lol.

sorry, i'm tired.

here's an idea. adust the u-bar on the hatch latch (haha, i rhyme) so that if there is enough pressure to actually lift the rear end, it will lift the hatch however much you allow in the design and vent the pressure.

nimrodTT

so it gets scary when you want to slow things down... interesting.

Jerm982

HAHAHA

Does that really do anything at all?

ben79

This is the same reason I was surprised to see a Mariah body kit peice which had this hatch replacement. I thought body kits were supposed to be aerodynamic, but this completely negates that. Notchbacks(think fiero) have notoriously high drag coefficients because the low pressure area which forms from the swirling air behind the rear window. This causes a suction which pulls backwards on the car and creates *huge* turbulance. Which, because of the time of night, i illustrated below
.........____..
..___/.......|@'_
<___________>@@@@
....O.............O

.........____ .......
..___/........\__- - - -
<__________> - - - - -
...O.............O

cpt_gloval

iTrader: (1)

i know it's a little late, but...

fastest i got my fb up to was 110-ish on I5 just south of bellingham WA. i had to back off 'cause i hit a curvy section and almost drove into the median...

riffraff

jerm982.. it adds some stability, and makes the car less likely for lift..

i remember , back in the good old days, when my father had an second gen (n/a). raising the sunroof made a lot of difference on that car too.

Node

iTrader: (1)

George (Exit13B) had his full bodied bridgeported FC up to 194MPH. I don't see why it's hard to believe. Not like the car is going to fall apart. As long as you have some sort of downforce. FB's aren't shaped like bricks. They're actually quite aerodynamic.
I see no reason why he couldn't get up to 200mph besides instability. Something to help that double edged sword you guys have for front bumpers would help a lot

Node

iTrader: (1)

I know for a fact that the sunroof (or is it moonroof, i always forget which is which) was meant to be used to create additional downforce when open.
Mazda rocks

peejay

I think having the sunroof up would help, but not for his reasoning. It would vent high pressure air from the cabin into a low-pressure area (the air over the back of the car). Having more pressure over that area means less lift and less drag.

People gripe about how ugly the C5's rear end is... i think it's beautiful, but then again that's how I feel about almost all purely-function designs. It generates downforce with very little drag by making sure the low-pressure area is underneath the rear, not above, and it doesn't require a big ugly spoiler or wing to make an artificial high-pressure area above the car. Like I said, it's beautiful!

speckamp

Yep, I've noticed a signifigant difference in the stability of the car w/ the moonroof (sunroof, metal thing, whatever) open / closed / off. Open being the best, off being...well intresting.

Kinda cool that they'd think about that in the design.

--matt

edit: oh yeah, max speed reached = 121MPH (end of 4th gear)

itzweapon

140+ mph..
SE rear..
89 Convertable Gearbox..
14psi of boost..
Just over 7500rpms..
15 inch Epslions w/225-50's on the rear..
Now this can be either a few miles under or over 140mph.. because @ these speeds.. the speedo is not accurate. Most of the older cars.. where not expected to reach these types of mph.
I'll have to be honest.. I've to admit.. this was a short test if top end speed. My SE did not feel stable at all. I have a full body kit.. including a rear deck spoiler which , to me , didn't help much. Now the time it took to get to 140+/- did take much time :]