What's the likely outcome if I put a pair of 145's on the FRONT instead of the 125"s ? Would this overcome the understeer problem ? (Not on the existing rims - say a second set as the rear). Would they fit ? I like an oversteer bias - just a preference from other times/cars. Love a little drift from time to time!

FROZTY

 

Hey Frosty ... what do you mean my 125s amd 145s? Do you means putting 245s at the front instead of 225s? If so, then that is what I was thinking about doing as well. I don't want to throw out my practically brand new 225s, but for my set of racing rubber definatelly.

I think that it will certainly help .... again, as I mentiond on another thread, if someone wants to sell their 1/2 worn (well still road legal) 245/45/18s, then let me know as I'd love to give it a go.

Oh, and the OE 18" rims seem to be exaclty the same width at the ront and back so there should be no problem with fitting 245s at the front.

I like an oversteer bias - just a preference from other times/cars. Love a little drift from time to time!

I'm not sure if 245 tyres at the front alone will make this car have 'oversteer bias' .... I'll be happy with 'neutral' or just closer to it.

ps. I'm looking into swaybars to provide a solution, so I'll let you guys know if I find something that sounds good.

 

Well.... as I can feel on my car with 245 at the front and 275 at the rear.... it does not make any different from running 225 and 255 with those spacers on.... the car's turning characteristic is near EXACTLY the same and the way it handles the twisted corners are quite similar to I used to feel.... just that you can feel the steering is a bit heavier which I like it a lot due to the extra weight at the front end.

In terms of oversteer... well... it does not really give you that... if you want oversteer, just entre the corners with higher speed and with the VDC off, you will be able to get some! but just be careful with all other cars and yourself when you do so!

David.... I can definitely tell you that the sway bars does HELP in turning A LOT.... I don't have the sway bars on, but I had a set of AC Schnitzer sway bars (adjustsable) on my AC Schnitzer (S3 Sport) tuned M3 and they worked GREAT compare to the standard m3 sways.... the improvement can be felt straight away! The car tends to sit flat on the road when you entre the corner and I think you will feel this even more in the Z as the Z is already designed to sit FLAT when you corner. With those anti-roll bars, you will love every turn you make!

I am planning to get a set of nismo dropped on to my car some time next year, but just not sure when thought....

cheers,

richie

 

Well.... as I can feel on my car with 245 at the front and 275 at the rear.... it does not make any different from running 225 and 255 with those spacers on.... the car's turning characteristic is near EXACTLY the same...

Hey Richie,
With your 2 different tyre sets, it does not look like you would change the 'characteristic' of the car at all as each time you have retained the same width-ratio between the front and rear tyres.

I want to put 245 tyres all the way around (ie. front and back). I don't think the actual width makes too much difference to the balance as you just want more grip at the front than the OE setup gives you.

In terms of oversteer... well... it does not really give you that... if you want oversteer, just entre the corners with higher speed and with the VDC off, you will be able to get some! but just be careful with all other cars and yourself when you do so!

I am trying :-) Though, too much entry-speed seems to result with immediate understeer for me. What speed corners are you talking about? I have only really tried it through 50 - 80kph (at the apex) corners and once the front starts pushing, then there's nothing else but that (ie. front push).

Closest to oversteer that I have come is on the corner exit. That is by slowing down the entry, hitting the apex and then squeezing on the power. Still, even that sometimes results in (mild) front push so the oversteer can't happen.

ps. Not that I want to turn the Zed into an 'oversteer monster' ... I just want more front-end grip.

David.... I can definitely tell you that the sway bars does HELP in turning A LOT.... I don't have the sway bars on, but I had a set of AC Schnitzer sway bars (adjustsable)...

Whiteline make a stiffer (adjustable) rear swaybar. That will give the car a more neutral balance, but it will do so by making the rear looses (ie. less grippy). I'd rather do it by generating more grip at the front. I'd say that for that I'd need 'softer' front swaybar than what the car comes with. Whiteline do provide an adjustable front swaybar as well, but again, it is stiffer then OE. I'm trying to find out more about why it is stiffer, but generally speaking you put on stiffer swaybars to generate more understeer (and inedvertedly tie the back down a bit more).

I am planning to get a set of nismo dropped on to my car some time next year, but just not sure when thought....

Do you have any info on the Nismo front swaybar? Do you know if it is softer (or stiffer) than the OE one? Also, do you know how much they are asking? Whiteline (adjustable) swaybars are around $250 (AUS).

 

David:

The corning speend that I do is roughly around 30 to 40 at the normal street corners without applying any brake but gas (left turn).... I normally travel at 60 to 70 then late brake, heel and toes from 6th into 3rd (engaged the clutch half way), then immediately heel and toes again into 2nd and by then, I was at the "corner" of the street and I apply gas AT the corner... you can lose the tail that way (even on the slope) but not for long.... you can even feel that you lose the tail A BIT with the VDC on... oh yeah... and greater effect in wet OF COURSE!!!

I am not too sure wheather or not nismo does provide a softer version sways than the stock (or even an adustable ones).. but I know most of the after market tuning houses always supply stiffer sways(thicker) than the stock! I forgot which way round that you can change the turning characteristics to oversteer.... (soft front and stiff rear or soft rear and stiff front?!)... but I am sure with the adjustable sways, you can definitely adjust the front to be a bit softer than the rear (although with the fixed settings, depending on how many holes they have at the end of the sways), hence you can achieve the over-steer easily!

cheers,

richie

 

I have the Nismo sways and I think they do help. ZZZ-35 recently came and had a look at them and has the latest price info ...

 

soft front and stiff rear

That will create more front grip, and less rear grip. (ie. less understeer and more oversteer).

soft rear and stiff front

That will create more rear grip, and less front grip. (ie. more understeer and less oversteer).

...but I am sure with the adjustable sways, you can definitely adjust the front to be a bit softer than the rear...

That depends on the bar. I would love to get a front swaybar that allows me to go softer as well as stuffer just to have a broad range of adjustment. Though, the Whiteline front swaybar on the softest setting is still 9% stiffer than the OE one. That will just give me more understeer and (I'm guessing) is their way of making you buy both front and rear swaybars (where the rear can be set even stiffer).

Ideally, I'd like to replace only what I have to, and that at the moment seems like the front swaybar (and camber kit).

I have the Nismo sways and I think they do help.

Hey Dixonbn, maybe we can meet up one day so that I can check out the swaybar and see what difference it makes. Would that be possible?

btw, do you have just the front, back or both swaybars in your car? Also, are they adjustable, and if so, how have you got them set-up?

 

David - are you sure that the rear rims are same as front? - I seem to remember Harry saying that his rear didn't fit the front (or was it the spare?) - anyway, 245 v 225 is a 10% increase in potential traction - just about what the doctor ordered - but the overhang of sidewall on the back doesn't seem to indicate 10mm additional to rim width compared to front.
I hope you're right, though - love an excuse to pissoff the feathered fronts. If feathering could make me fly, nobody'd catch me !

FROZTY

 

David:

I found out that the Nismo front sway give 20% more stiffness to the front and 37% stiffer to the rear than the original setup! So that will definitely help you out!

cheers,

richie

 

David - are you sure that the rear rims are same as front?

Yep, as long as we're talking about the 'track' model factory 18" wheels, then yes. The Nissan literature has them listed as the same width and also I have a spare set of 4 wheel sitting here and they have exactly the same markings and I cannot tell them appart. Putting them all next to each other does not indicate any difference.

As I mentioned before, if anyone has OE 245s that are still road-legal, then I'd like to take them of your hands and try them out.

anyway, 245 v 225 is a 10% increase in potential traction

Exactly :-) btw, Nathan has 255s all around on his race-prepped Zed. That seems to indicate to me that having the same with front and back is the right way to go.

I found out that the Nismo front sway give 20% more stiffness to the front and 37% stiffer to the rear than the original setup! So that will definitely help you out!

Thanks Richie. Not exactly what I was hoping for as you need both the swaybars to apply the 'fix' (ie. same as with the Whiteline swaybars). Besides that it still seems like they are 'fixing' the problem by making the rear looser. It is possible that the back is just too soft (out of factory) and that it is necessary .... I'll have to investigate a bit more to understand the OE setup a bit more.

btw, the Whiteline swaybars offer something like +9% to +38% extra stiffness at the front and back. So the front can be set as low as +9% over OE while the rear can be set at +38% over the OE setup. Still, that is the same solution as the one Nismo offers.

If there's no such thing as a softer front swaybar, then maybe it's worthwhile starting with just the stiffer rear one ... WRX guys do that often, but then the WRX has understeer in a totally different league to the Zed, so a 'loose' back is something they strive for.

 

It makes sense to add a rear sway bar with a mild stiffness. We don't have massive understeer like the wrx.

What the price like for rear sway bars anyway?

 

It makes sense to add a rear sway bar with a mild stiffness. We don't have massive understeer like the wrx.

WRX guys add stiffer rear swaybars to deal with the understeer (which they have a lot of). It in a way makes the rear grip less so that is why I'd rather softer front sway-bar. Still, as I said before, maybe the rear swaybar would do the trick .... I just do not want to loose any rear grip (if possible)

What the price like for rear sway bars anyway?

The Whiteline adjustable swaybars (front or back) cost just under $250.

 

Nathan - What brand and profile 255's all round ?
ANYBODY - Given the trouble I've had/having with tyre roar and consequent bad front tyre sensitivity and understeer, I rather like the sound of uprating and putting larger tyres than spec to front - ie same all round. I want a tyre that doesn't have the "fish scale" style flats so that they can't feather - and at the same time increase the footprint all round.

What's the profile % ? I would like to keep the height AS IS - ie may have to go to 255 40 19 ? What's available?

Also, wider tyres on same rims - won't I just be pulling the walls back in and achieve very little in footprint ?

All a bit mind-boggling - might go and open another bottle of cheer.

ps - Mary has been stuffed in the chimney.

 

Also, wider tyres on same rims - won't I just be pulling the walls back in and achieve very little in footprint ?

If you're talking about 245s, then it'll do the same thing as it does on the rear-wheels as the wheels at the front are the same width. The OE 18" wheels are 18x8" all around so there's no problme with 245s at the front.

I want a tyre that doesn't have the "fish scale" style flats so that they can't feather - and at the same time increase the footprint all round

Sounds like Pirelli P-Zero Rosso (http://www.subaru-sti.co.jp/s202/image/tune_02_03.jpg), or Continental ContiSport2 (http://www.e-tyres.co.uk/images/cont%202.jpg). Both great tyres, but both expensive. Falken Azenis RS (http://www.stamfordtyres.com.my/pass...ken_azenis.jpg) would satisfy your requirement as well, but the tyre will not last long even though it should be cheaper.

What's the profile % ? I would like to keep the height AS IS - ie may have to go to 255 40 19 ? What's available?

Not sure how much wider you can go on the standard rims ... I'd guess that 255 (and maybe 265) is possible, but at the same time I'm not sure how much clearance there is at the front.

Though, if you wish to keep the height exactly the same (as you certainly should at the back at least), then you'll need to go to 275/40/18". Those would be great tyres .... but I don't think you'd be able to fit them on OE 8" wide rims :-(

 

Thanks David - have a happy ! ! !

FROZTY

 

I ran 255 at the rear without any worries at all! So you guys can be able to put 255 or even 265 at the rear.... I have a few pics for those track wheels to have 275 all around... but the tyres look really bulged out though.... I got those pics while back from one of the guy in this forum! If anyone is interested in seeing how they look, just let me know!

anyway..... Have a VERY MERRY X'mas guys!

cheers,

richie

 

These increases in swaybar stiffness are not as dramatic as they sound, because 1) stiffness is a function of the spring/bar combination and 2) the wheel motion ratio reduces the effectiveness of the bar (or spring) in terms of absolute numbers.

According to my homework, the OEM spring-rates at the wheel are 113 front/95 rear. The OEM bar-rates at the wheel are 204 front/95 rear. So, OEM-wise, front/rear total rates are 317/180. That's a ratio of 1.76:1.

If you upgrade to bars with a 9% front/38% rear rate increase, the total front/rear rate becomes 335/226, for a ratio of 1.48:1, front/rear. I don't believe that constitutes excessive "reduction" in rear grip.

My own experience is with the 3-position-adjustable Stillen bars, which I had set @ 7% stiffer (soft position) in front and 33% stiffer (middle position) rear. They made a nice dent in the understeer tendency, yet the rear grip was still prodigious.

 

Thanks Lateapex, that was very informative. So it looks like the Zed is generally setup with a (generally speaking) stiff front and soft rear. Maybe the rear can use some stiffening up. Can you shed some light on the power-down characteristics of the car with the Stillen bars set as you have them? I'm interested to know if you noticed any difference from OE. Also you mentioned that this setup put a 'nice dent in the understeer tendency' ... are you implying that the front now had more grip?

Also how much were the Stillen bars?

ps. I just noticed this in your signature:

- Comp tires/wheels: 275/40 Kumho/17x9
- SPARCO Torino seat

Do you track your car? If so, where? Also how much were the tyres as well as the seat?

 

[QUOTE]Originally posted by frosty
[B]Nathan - What brand and profile 255's all round ?

Our car was converted to race spec when it was brand new so I have no experience as to what is a good road tyre on the Z.

What I will say is, Kumho's MX patten tyre is very very good tyre & when you take cost into consideration they are unbeatable.

There have been a few independant reveiw's done in the States where they come up every bit as good as Michelin Pilot Sports & Brigestone S03,s. whether they have a size that fits the 8" wide Z wheel i'm not sure.

 

I didn't notice any loss of grip in power application, just more tendency to oversteer in extreme slalom maneuvers. I needed to be more at-the-ready with opposite lock. Yes, the front had more grip, but it still had too much understeer under race conditions.

The Stillen bars are around $500 US for the pair.

I slalom, and do some track-days with the Alfa club at a couple of venues in the Seattle area. The tires were $170 each, heat-cycled and the seat was $750 w/the mounting bracket.