1 registered members (James),
354
guests, and 2
spiders. |
Key:
Admin,
Global Mod,
Mod
|
|
Forums69
Topics113,873
Posts1,343,466
Members1,596
|
Most Online731 Jan 14th, 2020
|
|
|
Re: rear stifness
[Re: kj16v]
#1222445
01/06/2011 17:43
01/06/2011 17:43
|
suba
Unregistered
|
suba
Unregistered
|
Front upper strut brace makes A LOT of difference...it very easy to test this with a back to back drive with one on and then it off.
|
|
|
Re: rear stifness
[Re: crgracing]
#1222653
02/06/2011 03:08
02/06/2011 03:08
|
Nazo
Unregistered
|
Nazo
Unregistered
|
This may go against most guys experiences, but I have now changed all 4 springs from eibach to the Group Buy CountryCrusing ones.. They are more progressive and I find the rear has better handling both in corners and over bumps.
You can call them progressive springs..and they thicker then Eibachs.. Its a cheap and simple change.
I know adjustable shocks may also improve things, but everyone has different opinions.
|
|
|
Re: rear stifness
[Re: crgracing]
#1223017
02/06/2011 23:09
02/06/2011 23:09
|
Joined: Dec 2005
Posts: 17,370 Staffordshire
Nigel
Forum veteran
|
Forum veteran
Joined: Dec 2005
Posts: 17,370
Staffordshire
|
To be fair, there's only one or two people saying they make no difference and many, many people saying they've improved the handling of their car.
I've driven LOTS of Coupes, in many states of tune and chassis configuration. I think I'm well qualified to comment on what works and what doesn't.
In my humble opinion, the best handling mod you can do for a Coupe is shocks and springs, followed by an uprated rear ARB. Next comes a bit more negative camber at the front, followed closely by an upper strut brace and then my lower subframe brace. Personally, I wouldn't bother with an uprated front ARB unless you've already gone VERY stiff on the rear ARB and need to balance it up a bit.
As Gunzi suggests, I reckon if you stuck a pair of braces on a standard car, the difference would be very noticeable. Adding them to a car with a host of existing handling mods will be less noticeable.
|
|
|
Re: rear stifness
[Re: Nigel]
#1223080
03/06/2011 02:41
03/06/2011 02:41
|
Per
Unregistered
|
Per
Unregistered
|
and then my lower subframe brace. ...or any lower subframe brace.. Yes it does make a big difference, more so than the Sparco strutbrace I'd say.
|
|
|
Re: rear stifness
[Re: crgracing]
#1223236
03/06/2011 16:47
03/06/2011 16:47
|
sparco
Unregistered
|
sparco
Unregistered
|
Mmmmm i'm very interested to hear peoples views on handling and like Nigel i reckon i am pretty well placed to pass comment, all be it however on a pure race set-up. There are fundamental things that if done will improve the handling of your coupe or any car for that matter. What you then have to do is fettle your car to how you drive. Somoe people will not like a vervous and skittish rear end on a fwd, personally i quite like it as it's much faster on track but i certainly wouldn't want this in a road car where progressive handlig on the limit especially in a FWD car is absolutely a necessity otherwise you will find yourself backward into the scenery. However there is also a school of thought where some people have completely different set-ups yet are just the same on track, this is all down to the driver. However i emphasie this is on track only. On the road it needs to be a little supple. The roads in the UK are not smooth and always contain diesel, oil and other contaminents which make the road surface very slippery when wet. Unfortunately we don't have the luxury of dry weather predominently.
I agree that the strut braces will help on their own and if teamed up with better suspension and spring ratings you will get a road car handling pretty well. Everything is a compromise and the more you fettle the less time tyres, brakes and suspension lasts before it wears out. Making something stiffer will put pressure on something else further down the chain.
I'm now running 750lbs springs on the rear of my car and 850lbs on the front, with race spec dampers, every brace known to man and some serious geometry settings. My coupe is still not the best handling FWD car in the race as newer more advanced cars such as the Seat have a better foundation to begin with and more technolgy. You can only pee with the winkle you are given so to speak.
|
|
|
Re: rear stifness
[Re: crgracing]
#1223268
03/06/2011 18:54
03/06/2011 18:54
|
sediciRich
Unregistered
|
sediciRich
Unregistered
|
Nigel recall the chassis is from the 1980's, recall what cad would have been back then and the effect that would have on iterations. The base car was not of a performance starting point, the earlier generation Leon Supercopa had custom uprights I'm darn sure the later version has even more custom items (One of these also one the eurosaloons championship a few years back), also we cannot be sure without looking what type of suspension method they are employing including the design (double wish bone perhaps) and the type of antiroll bar - bars which are far removed from the bits of wire used on our cars - I know the Alfa 156 ST has hollow bars in the 50+mm range, such that the roll resistance is mainly ARB and not springs.
The Tipo design of high outer wishbone position gives a poor force application point in regards to inner wish bone position. Also the upright will lack rigidity compared to modern designs - this is very apparent with the BMW mini such as the challenge version I picked up recently on behalf of my brother and took a look round) in the mini the lower ball joint is as low as it can be, enabling the wishbone to be far more level at ride height thus less angled in the roll.
McPherson struts may not be the worst part of the tipo design but the trailing arm might well be as there is no camber recovery in roll. I think the evolution to the 156/147 chassis shows the progression to what should be superior front double wish bone and rear McPherson struts, and if you look at those alfa you will still see the Tipo underpinnings albeit with added sections to accomodate the new suspension.
The tipo along with its coupe counterpart are very flexible chassis, with the coupe probably benefitting fromt its shape over the hatch back but they cannot be a patch on modern cars iterations between lancer evolutions show how rigidity can be increased substantially without noticably radiacally changing the shape.
The fiat is not a great place to start from or rather its original design was a mass market road car which then tried to become a sports car - fiat did do a few things Tipo to coupe like wider track, then the turbo models got substantially beefier uprights, but as you know alfa went further with the 916.
When they races the 155 d2 everything was custom, but they had to keep the same rear suspension configuration, a thorn in their side, but nothing was shared with the production vehicle aside from the chassis mounting points. This is not quite the same for the 156 ST where you can see a production front and rear sub frame (modiefed for a plate brace at the front) and modified production wish bones, the uprights again a near as custom as they can be. Although its unfair to compare home brews with factory challenge cars which the likes of the Clio cup and Leon supercopa are, developed on €100K+ budgets
850 fronts Marco!, maybe I can go stiffer! Currently 627 and tons of understeer, rear was wound up for Trevs last race still didnt seem to help.
I estimate eibachs to be 70Nmm so 400lb/ft as a guess.
Last edited by sediciRich; 03/06/2011 19:33.
|
|
|
Re: rear stifness
[Re: ]
#1223273
03/06/2011 19:16
03/06/2011 19:16
|
suba
Unregistered
|
suba
Unregistered
|
The Tipo design of high outer wishbone position gives a poor force application point in regards to inner wish bone position. Also the upright will lack rigidity compared to modern designs - this is very apparent with the BMW mini such as the challenge version I picked up recently on behalf of my brother and took a look round) in the mini the lower ball joint is as low as it can be, enabling the wishbone to be far more level at ride height thus less angled in the roll.
This is why lowering a coupe does not help make it handle - nice description Rich!
|
|
|
Re: rear stifness
[Re: crgracing]
#1223388
04/06/2011 08:50
04/06/2011 08:50
|
sparco
Unregistered
|
sparco
Unregistered
|
The standard fronts are indeed about 400lbs and the rears 350 maybe. Not sure about the Eibachs Nigel and you know how secretive Eibach are when it comes to spring rates!
Very informed reply Rich and right on the money. Technological advances in chassis design make a world of difference and even a standard modern clio or the like will outhandle a well sorted coupe. Rich i have loads of springs if you need any to try mate.
That's why i love making my car go se well, it's bucks the trend and makes people see what it is really capapble of in the right hands and with the right set-up. Yes i do have to drive it like i've stolen it but is that not just more fun again. Come and watch me through the twisty section of knockhill and there is lterally nothing any quicker down through there. That's not my own opinion that's people standing watching. That makes me proud to be competeing in my old Fiat!
|
|
|
Re: rear stifness
[Re: ]
#1223420
04/06/2011 11:20
04/06/2011 11:20
|
sediciRich
Unregistered
|
sediciRich
Unregistered
|
Suba -Well its is off set by the lower CofG, but when the angles get extreme its bad. I was upset by that mini, it had everything I wished the fiat had, no wonder they handle well.
Still the Stilo had rear beam suspension a totally retro grade step over the tipo based designs.
Marco, are they 60mm I'd like to give it a stab, I noted the lap time change you found on the front increase in rate.
Last edited by sediciRich; 04/06/2011 11:28.
|
|
|
Re: rear stifness
[Re: crgracing]
#1223427
04/06/2011 11:33
04/06/2011 11:33
|
sparco
Unregistered
|
sparco
Unregistered
|
Yes i have 60mm fronts, 650's 750's spare.
|
|
|
Re: rear stifness
[Re: crgracing]
#1223438
04/06/2011 12:28
04/06/2011 12:28
|
jonone
Unregistered
|
jonone
Unregistered
|
Std front springs are surely not 400lb?
The Gaz road/trackday kit was sold with 425lb front springs and that's rock solid on the road!
When I had the 8" 425lb springs on the front of my car all I got was a crashy ride and loads of wheel spin.
The problem with my Gaz setup is, if you use a tender spring the platform between the springs rubs against the body, so I have been forced to use one single rate spring, I have ended up with a 300lb front spring, which for me is about right on the road, I would like less body roll but when you up the poundage the ride goes to pot. My only other option is to get a dual rate or progressive spring made so you still get a decent ride.
There is a debate if the eibachs are progressive or not, maybe this is how they hide there poundage? but i will be shocked if they are more than 300lb
|
|
|
Re: rear stifness
[Re: crgracing]
#1223968
06/06/2011 10:29
06/06/2011 10:29
|
gassy
Unregistered
|
gassy
Unregistered
|
Im swapping the rear suspension on my fiat tipo for a alfa gtv remove spare wheel well tank in boot powerflex bushes it can be done to a coupe aswell tipo
Last edited by gassy; 06/06/2011 10:35.
|
|
|
|