Reducing understeer on a hot hatch?

[RedLexus]

My fun car is a Mk1 Golf Gti , I love driving it , but want to really sharpen the turn in...Curently it's stock suspension , but I've a Weitec 60/40mm drop suspension kit going on , approx 20% stiffer , with sticky 185/60 14 Yokohamas on . What else is known to be good for sharper turn in? The front and rear ARBs are standard . Which one reduces understeer , the front or the rear?
Suspension is McPherson front , beam at rear .

[myte128]

Stiffen the rear ARB for less understeer. A bit of negative camber at the front should help nicely with your turn in response. Nolathane bushes will help turn in feel sharper (less slack). Check with golf ethusiats to see what is a good set up, it is always good to have a bit of research done for you which hasn't cost you a cent.

[RedLexus]

thank you for that , I've Poly bushes in most of it , and luckily camber is adjustable on the front . I have about 1 degree of neg on , at the mo .

[Georges Fonso]

Hi!
From my Golf Mk2 Experience, apart from playing around with Anti-Roll Bars (and you can still get some quite beefy aftermarket ARBs for the MkI Chassis), great progress can be done by playing with the car's track. I swapped my front lower wishbones for the ones from a Passat 35i, which increased track by 52mm at the front. So, the original 1427/1422mm front/rear became 1479/1422mm. Interestingly, the Passat rear axle is not a mm wider than the Golf, despite a 150mm longer wheelbase.
Now, the change in handling and balance was just about enormous, and I got myself to drive a totally different car. The increased Ackermann, in conjunction with some rather aggressive alignment (2mm toe-out, -2,5deg camber, 2,5deg castor) meant that the steering was slightly insensitive for around 20 degrees each side of the straight ahead position, but after that the car responded as if somebody was pushing on the fenders! Also, the front became literally bolted to the tarmac, which made the rear very very lively but never unpredictable. The handling became very throttle adjustable (and sensitive), understeer eliminated unless you got the wheels to spin madly!
All of this is with an open diff BUT with a very sophisticated suspension, with 40 "clicks" on the shock absorber's rebound settings and 30 "clicks" on the bump settings, coiolver design with external gas bottles (and lots of hilldriving to set it up properly for road use).
Wheel spacers could be sort of "half-solution", but you don't get the benefit of moving the lower McPherson balljoints further apart or extending the tie rods (again, I used Passat ones), which is good for reducing bump-steer. In the case of the MkI chassis, I'm afraid, there is no "bolt-on" wider control arm/ tie rod solution, BUT i think that tubular rose-jointed control arms a-la-VW Motorsport style can be fabricated "relatively easy"... You can definitely find them off the shelf from various German outfits that get involved in Group H Hillclimbing ("Berg-Rennen") and Slalom Racing, but I have no idea regarding to cost.
Also bear in mind that engine mounts play a big role in those cars, and stiffer mounts will most definitely improve turn-in and front-end stability. Also, another point to remember, especially if you lower your car that much with the suspension you have: under no circumstances should your control arms get to point "upwards", they should at most be parallel to the ground, and that is with you in the driver's seat. Lowering the car as much as to get them pointing upwards will ruin turn in and induce too much understeer, your front suspension kinematics will go out the window. Should you want to radically lower the car, you will have to use "ball joint spacers", imagine a sort of sleeve that fits over the original ball joint and extends its shank about 25mm, allowing you to further reduce ground clearance without getting the control arms to point the wrong way... Otherwise, in case you go for tubular control arms with rose joints, it even easier to fabricate the correct rose joint fittings in order to achieve the ideal control arm position/ ride height for your application.
Also, a couple of things to bear in mind regarding "low budget coilovers", widely used in the VW world, designed mostly for low-riding poseurs rather than elaborate drivers who wish to really tune their suspension: they most definitely get the car down to the ground and give you a harsh (sometime terribly harsh) ride, but they' re not really worth much when it comes to handing impovements at all. I What you get is merely from lowering the chassis, their damping settings are all over the place and only suited to some very flat and smooth tracks with lots of grip. Having driven quite a few of those suspensions I've resorted to either custom revalved sport shocks with custom adjustable spring perches or a suspension like the one I'm using now (and with which I am most satisfied). The downside is that it might cost more than the actual car! Just a matter of taste and priorities...
And, don't be afraid to reinforce your chassis, especially a well-worn and quite old one as a MkI Golf. A good strut brace in combination with lower track control arm braces will work wonders. The same goes for rose-jointed aluminium top mounts for the front McPherson struts, which will not only keep the struts steady under vigorous cornering (the rubber top mounts are extremely comliant, you will be terrified by the amount of camber lost during cornering!) but will also enable you to adjust your castor angle, very significant for fine tuning!
Best regards,
G.F.

[RedLexus]

Many thanks , I am machining up some ball joint spacers , to raise the roll centre after lowering . The Berg Cup cars are unacceptable machines..I love them! Wide tracking a MK1 is not so simple sadly . I have uprrated front and rear engine mouts in already , made a noticeable difference.

[Georges Fonso]

Ah, yes, those Berc Cup cars...
As long as the balljoint spacers go, BEWARE of DIY jobs. Material selection/ stress relief/ heat treatment / corrosion protection is VITAL on this sort of machined parts. Don't forget what relies upon them, that's why I haven't got down to making them myself (well, yet, anyway). At least find some engineering firm or machine shop with sufficient engineering / metallurgical background that can make them last with no hassles and worries. Wouldn't like to inspect the car and find a spacer cracked or, worse, have it break while I'm driving the car in anger!
Best regards,
G.F.

[RedLexus]

Dead right! when I say I am machining them , I should in fact have said my friend , who has a CNC machine shop.

[smckeown]

additionally to the above, your tracking also has a major input to the steering. Check your toe settings, for a track car yo want a little bit of tow out, that will havea significant impact on reducing understeer.

Get yourself a trackrite to be able to se it yourself, at tow out isnt suitable for a road car, as it will produce uneven wear on your tyres

As other have said, stiffening the rear is the main area of concern for a FWD

Sean

[Kev Rooney]

I'd agree with altering the toe to sharpen the front end response , 3mm toe out will definitely make it turn in quicker but at the expense of a twitchier straight line drive so primarily a track mod. Also wheels spacers could be used as this will move the tyre /kpi intersection point and result in the tyre 'pivoting' in an arc as opposed to around it's centreline. Steering in either direction effectively shortens the wheelbase a 'tad' resulting in quicker turn in with none of the twitchiness of the tracking mod.