geisha8

My 8 is bog stock standard. Everytime I take it up to 170km/h it starts to feel light and starts to get a little unstable at 180+ and I have to back off. There is clearly too much lift and not enough downforce esp at the rear. Has anyone felt this? A rear spoiler would probably help. I'm thinking of a MS unit; expensive but probably worthwhile (a heckuvalot cheaper than losing traction at those sort of speeds). These speeds are of course done on a closed circuit. Another option would be to do what ADR does to some learner approved bikes - limit the throttle range; cheap too hehehehe....
Any suggestions boys and girls? Arigato!

takahashi

Hi mate... long time no see.

You know that I have a MazdaSpeed spoiler and OEM front skirt; and I track my car a handfull of times at Sandown and it does go up to 195kmh. I can exactly remember what it feels like stock. I definitely track the car in stock (no wing) once. And I put the wing on when little Taka is 10 weeks in gestation (I know I had to take her mum for ultrasound that day. .... let me think.... I can't really tell now --- :D ---- It is certainly not a DRAMATIC difference that you will go wow. There is certainly a drag from those wings and Mazda claims to drag coefficent increase from 0.305 to about 0.33 with the wing on (which is not a lot if you play GT4 in a PS2).

That is my $0.02. It may be a lot of sense to get the body kit and lower the car to limit the air flowing underneath, rather than spend possibly $1800 for a genuine wing..

Mind you the MS wing looks awesome and it is worth the $$$ for the bling.

geisha8

G'day Taka
I would have thought that the rear wing will create a lot more downforce while the front spoiler will help deflect some air from the bottom of the car. I'm surprised there is only a slight difference. Hmmmm..... if there isn't much difference, I'll save the $$ Maybe just the front air dam? I can't lower the car as with a dented heat shield it's just clearing my driveway I guess I'll just have to go fast on my bike instead of my RX-8 :D Any suggestions Dr Taka?

takahashi

Well for anything the weight of the spoiler will help too... u can tell that it is heck of a lot heavier in the boot lid after the wing installed. Hmmm... I can't tell you more about the MS wing except it is a damn good look.

What I found that the wing can be adjusted and I swear it helps with planting the rear end under braking ... you see the rear feels like they are floating and wagging a little under brake - especially the bumpy 1st turn at Sandown and the rear wing helps - even creating the angle - it helps!

geisha8

EXACTLY!!!!! There is a lot of weight transfer from rear to front under brakes. Firmer springs might help too as will compression damping but OEM shocks are non-adjustable...... sigh...... guess I'll have to get my braking done REAL early at Wakefield esp Turn 1.

ILIV48

Having had to design rear wings, full body kits for Volvo Sweden (Yeah I know Volvo Ha ha) I can tell you most rear spoilers on the market for most cars actually create more lift than anything else. Just sticking a wing on a boot lid is not a good idea without looking at how the air is flowing over the vehicle and in particular coming off of the roof and across the rear window, not to mention how it exits the underneath of the rear.

A good suspension setup (not just springs) will have a greater effect on keepng the RX8 planted than slapping a small wing on the back. By reducing the amount of movement in the balance point of the car under acceleration and braking you can much reduce what you are feeling. Under hard acceleration the weight (balance point ) of the car moves to the rear causing the front to become lighter while the front also raises up allowing a greater volume of air underneath. The end result is loss of steering quality and instability. If you then just even throw in a few small bumps you have an RX8 that feels not so good at 190km/hr.

Get the suspension sorted and you can significantly reduce these effects and improve the feel at speed. A lot of the big wings you see on racing cars are used for corner speeds more than stability on the straights.

I personally think the RX8 is just painfully under dampened and attention in this area has big benefits in all the facits of Performance & handling! Drive an RX8 with some well sorted out suspension and you immediately notice the diiference especially over 130km/hr!

Cheers

takahashi

Stu,

It is a big statment considering the Wheels magazine has quoted Alan Horsley's decision of not to have an aftermarket suspension in his car.

I hope you are right that "any good suspension is better than stock suspension" :D

ILIV48

I think you will find that if they were still going to put it in Targa and could change the suspension they would. With what they are using the car for now why would you change it. The stock setup is a brilliant compromise. The RX8's suspension is great for road driving, comfortable and handles very good. In the wheels article they talk about how civil it is to drive and to me that is what they are demonstrating. It can be force fed and made fast and still remain a very nice car for the daily drive or extremely fun for the spirited run... But for serious speed and track work it does have it's limits.

I'll stand by my statement of good suspension is better than stock. Taken out of context like that can make it look wrong. Kept in context though of high speed stability/handling and having been sorted & setup properly for the 8, it will be superior for this task. Would it be better for everyday driving for most people... No because it will be at the sacrifice of comfort.

And remember thats good suspension setup properly not just thrown in :D

Once you get a drive of mine you will see what I am talking about although I like the slighlty harsher ride as it really now feels connected (you could almost say glued) to the road. I love that go-cart feeling though so what can I say :D

Don't worry Taka, with what I have felt with the new setup the TEINS FLEX you want will be well worth it indeed. You will not be disapointed although my option is alot cheaper :p

Revolver

What suspension mods have you made Stuart?

timbo

I would tend to agree with Stuart about the stock suspension being under-dampened -- especially at the rear (although I wouldn't say 'chronically' -- the 8 is very good in this respect stock, relative to other so-called sporting brands such as BMW, Audi and especially its nemesis - the stock 350Z)

That's why the first major suspension mod I would make -- and it's down the road apiece -- is to replace the OEM dampers with something like adjustable Konis. I would not like to lose that very fine handling/ride balance the 8 has.

geisha, I suspect damper replacement is going to address your problem more than any aerodynamic changes.

ILIV48

:D

labrat

Excerpt from the Labrat dictionary:

Spoiler n. What you put on a car to spoil 'er.

takahashi

Beauty is in the eye of the beholder, labrat.

Remeber: You are old and we are young

rotarenvy

are koni shocks that good? I put them on my last car and thought they were a waste of money. I wouldn't say it was a well set-up suspension but the kit was by a popular adjustable swaybar manufacture because of this experience I think koni are over-rated and I'm reluctant to touch the 8.

EZZY

i hope you were doing those 170km/h / 180+km/h in a safe, controlled enviroment

takahashi

Geisha said it is on a track EZZY.... read the first post :D

Was it at Eastern Creek?

People have mixed report from Koni, it is very personal and most reports are touch and go. You like it previously, you will stick with it; if you don't, you stay away. It is very hard to say, though, one product for a particular car will transfer to experience in the RX-8.

EZZY

oops..... :D

no wonder mum made an optometrist appointment for me for tomorrow..... maybe i need new glasses :p

does anyone remember those Audi TT flip incidents? they recalled them and fitted a little "kick up" rear spoiler to get more downforce....... i quite like the style of the spoiler :p

Wildcard

I'm about to move to the only state in Australia without speed limits and I am seriously thinking I might need some more downforce. I am wondering if the improvement in stabilty at high speed will offset the drag penalty? I'm not talking about a cosmetic spoiler here - I'm talking about a big-ish wing with some serious downforce.

xxup

Better get a couple of drop tanks fitted as the road in the only state (it is a territory you know) that has no speed limits has very few petrol stations.. Boy! Petrol is really expensive there too...

Wildcard

That's not as crazy as it sounds either!

Revolver

Wildcard, you simply cannot move there without FI. :D

MACCAA

Have run at Eastern Creek where you reach approximately 200kph on the main straight.Stability is very good,particularly as you have to brake hard to approx 160kph for turn one.
There is nothing wrong stability wise with these cars.I'd be checking wheel alignments and tyre pressures.
It ain't the car.

ILIV48

I put Koni's on my last car and frankly they did not do that much, so was not so keen for them this time for the 8. I did though do my research and spoke to people here and in the states that have tested HKS & TEIN and other brand coilovers and ended up prefering the Koni's as an everyday compromise as they seem to offer 9/10ths the performance without the coilover drawbacks and price!

Again though the Koni's are only as good as their setup. You have to get the rear damper settings right before they go in. If the setups not right you can really hurt the handling and I think that's the problem a lot of people have. Coilovers are the same!

These are for sure the best mod I have done so far in my mind. People are welcome to see for themselves at the Nationals. If your thinking of doing suspension then you will be more than welcome to have a drive of my 8 and make your own decision. I love them

ILIV48

Our biggest problem down here is end of the main straight at Sandown. It is very bumpy and that is what unsettles our cars. The car hits 190 and then you have to brake hard down to 100. The car does become unsettled. The back straight which is almost as fast we dont suffer the problem anywhere near the same extent.

labrat

....and the contextual significance is what?