Hello and road holding question...

[TheStoat]

Hi guys,

Finally managed to get registered on here and thought I'd say hello I have a 2004 SRT-10 convertible which is my daily driver. Particularly good fun in the winter!

Anywho, I want to improve the road holding and in particular the feel of the car when cornering. It seems at the moment to just snap from gripping to spinning which makes roundabouts interesting in the wet. Everyone is very polite when I spin because it seems to happen at quite modest speeds

First off is a full geometry check and an inspection of the tyres to look for signs of uneven wear or misalignment naturally. After that what would you guys recommend. I don't want to go spending ££££'s on replacement suspension at the moment. I rarely go on track so I reckons the standard suspension should cope with fast road use

I have non-runflat tyres already and that has made a big difference. With the standard 275x18 and 345x19 tyres what pressures do you guys recommend for good feel and grip?

Final question, am I best off posting this lot in the suspension forum or am I going to get more specific advice here?

Thanks guys,

Andy

 

[LifeIsGood]

Where do you live? Is the car stock...any performance modifications? What brand/model tires are you using?

 

[TheStoat]

Where do you live? Is the car stock...any performance modifications? What brand/model tires are you using?

Hi,

I'm based in the UK and the car is stock so far as I know. I've got the Michelin PS2s on the car all round. We only seem to get them or the runflat variants in the UK

Cheers,

Andy

 

[Black Moon]

Great tires for you. I run mine at 32psi. Check alignment, don't vary speed around tight curves and maybe a lighter shoe if all else fails

 

[TheStoat]

Yeah I've noticed the car *hates* changes in speed around corners or even gently trailing the brakes. Touchy isn't it?

 

[Bill Pemberton Woodhouse]

I hope some of your fellow Englishmen join in, as you have quite an enthusiastic group in jolly ole England, and they are also quite knowledgeable. Sounds to me that you might need to take some of the previous advice and have the alignment checked, as it should not be that touchy, especially at low speeds.

Check out some posts by our beloved crazy Nadine ( look under the Viper F1 post ) and send her a Private Message. She can definitely let you know whom to work with , but just from your post things don't sound completely normal.

Good luck and welcome to the site.

Bill Pemberton
Woodhouse

 

[mjorgensen Woodhouse]

The PS2 tire like a bit more camber then the run flats that came on the car originally. We have had good luck using -1.2 camber in the front and -.9 in the rear. The toe is generally 0 in the front and .20 degrees total "toe in" in the rear. If the car still feels too twitchy in the front ad .10 total "toe in" to get some stability.

the 32 psi is a good plan, but I like the extra predictability that I feel at 29-30 psi.

Good luck and welcome to the club/forums!

 

[Dom426h]

This sounds common of someone learning RWD.
Let me guess... You previously drove a FrontWheelDrive vehicle and were used to being able to apply the throttle around turns with no consequence?

What gear are you in when loosing controll around these turns? (please dont say 1st)

When checking the alignment make sure you have some TOE IN in the rear. That will help keep the rear end tamed.

 

[TheStoat]

This sounds common of someone learning RWD.
Let me guess... You previously drove a FrontWheelDrive vehicle and were used to being able to apply the throttle around turns with no consequence?

What gear are you in when loosing controll around these turns? (please dont say 1st)

When checking the alignment make sure you have some TOE IN in the rear. That will help keep the rear end tamed.

Doh! Guess again I've had a VX220 Turbo, an S2000 and a replica Cobra before this...

Gear makes no difference when turning, I'm on a balanced throttle and travelling at a realistic speed

 

[slysnake]

Keep in mind that I know nothing. But I bet you don't have any suspension problems. Would be mostly related to tires imho. PS2s are made to be a street legal race tire. The tread is set up for that too. I think there are some tires available (pernelli? not sure how to spell that) that offer a bit more tread for slippery conditions.

 

[Shandon]

I never liked the GenIII rear diff. Upgrade to a quaife for some real planted power to the ground. Do an alignment though first and see if that helps get you planted better.

 

[Dom426h]

Doh! Guess again I've had a VX220 Turbo, an S2000 and a replica Cobra before this...

ok I see... so you motoring experience is limited to:
an S2000 that has less than 100ftlbs of torque to the wheels at under 5000rmps
a VX220 that has less than 150ftlbs of torque to the wheels at under 4000rmps
and a cobra that i assume dosnt get out in the rain

A viper has Over 400 ftlbs of torque at only 2500rmps

Gear makes no difference when turning,

Depending on what RPM your at, Yes it does.
And here is an experiment for the skeptic:
In the rain. Go around a turn at 40 or 50mph in 1st gear and lift off the throttle. You will spin.
Same speed/gear, punch the throttle. You will spin

Now doing the same of the above in 2nd gear, the rear may or may not break loose, but if it does it will not be as abrupt giving you more time to react, countersteer, ect...
Now doing the same of the above in 3rd gear, no prob...

I'm on a balanced throttle and travelling at a realistic speed

If this is true than i'd say that you have a botched alignment with TOE OUT. Or a wrecked viper with a crocked frame.

One can be easily fixed. The other goodluck

 

[TheStoat]

ok I see... so you motoring experience is limited to:
an S2000 that has less than 100ftlbs of torque to the wheels at under 5000rmps
a VX220 that has less than 150ftlbs of torque to the wheels at under 4000rmps
and a cobra that i assume dosnt get out in the rain

A viper has Over 400 ftlbs of torque at only 2500rmps


Depending on what RPM your at, Yes it does.
And here is an experiment for the skeptic:
In the rain. Go around a turn at 40 or 50mph in 1st gear and lift off the throttle. You will spin.
Same speed/gear, punch the throttle. You will spin

Now doing the same of the above in 2nd gear, the rear may or may not break loose, but if it does it will not be as abrupt giving you more time to react, countersteer, ect...
Now doing the same of the above in 3rd gear, no prob...



If this is true than i'd say that you have a botched alignment with TOE OUT. Or a wrecked viper with a crocked frame.

One can be easily fixed. The other goodluck

You make a lot of assumptions don't you? All of my cars have been driven in all weathers including the snow. There comes a point where you have so little traction that the relative torque makes naff all difference. There's also a big difference between just lifting off the throttle and adjusting the throttle

Let's take a moment to clarify - I'm not new to RWD and all of my RWD cars have been used even in snow. I'm aware of lift off oversteer but that's not what I'm reporting here. It's the roadholding. There's too much of a tendency to bite in constant corners with such small throttle adjustments that the selected gear makes no difference

Anyhow the other guys have got the hang of what I'm saying and I'm going to ask *** what settings she's using for the geo and pressures

 

[mjorgensen Woodhouse]

OK I think there may be something we overlooked here lol, what is the temperature where you are and when you are driving??? Anything below 60 degrees and it is a prov-en fact that the Vipers grip is horrendous! Definitely NOT a 4 season car.

I know Nadine so tell her I said hi!

 

[TheStoat]

Yep, it is pretty chilly at times around here, below 10 degrees C a lot of the time. The Dodge has felt unhappy in warmer temperatures too though... Do you guys find the grip really drops off in the wet?

 

[mjorgensen Woodhouse]

Oh yea! some of us can drive them in wet/cool conditions, but I think the consensious is that unless it is nice and warmish out they stay in the garage!

Yep, it is pretty chilly at times around here, below 10 degrees C a lot of the time. The Dodge has felt unhappy in warmer temperatures too though... Do you guys find the grip really drops off in the wet?

 

[JonB]

Older RunFlat tyres are notorious for snap-spin, with NO transitional response to alert yoo...but NOT SO with PS2 !

PS-2 Tires actually have a recommended minimum temp of (I think I am correct) 38 degrees farenheit....I cannot grab my owners manual right now. The soft-rubber of the outer shoulder does NOT corenr well COLD..... but it is a great /excellent wet-weather tire in the warm. I have driven 130mph+ on PS2 on straights, with rooster-tails of water pumping out. Folks take front-straight pictures of Doris in her PS-2 shod wet Viper as well...PS2 is a confidence-inspiring wet-weather (warm-ish weather) tire.

MarkJ and I agree on baseline (cold) pressures: 29F 30R WHEN PROPERLY ALIGNED!

The kiddo above [who recommends pernellis] is also off on his Michelin analysis. He must be thinking about the Sport Cup as he wrote in error x 2. Disregard for your sanity and safety.

A also agree with DOM that 'sumthin is buggered' in your current alignment or suspension for the twitchy handling you recount. PS2 and good road should NOT handle that badly. {Bad shock maybe?.} Go with Mark's alignment figs....but look for some other issue at play for the underlying cause of the cornering spasms. Not Normal

Cheerio, and good luck

 

[Black Moon]

You make a lot of assumptions don't you? All of my cars have been driven in all weathers including the snow. There comes a point where you have so little traction that the relative torque makes naff all difference. There's also a big difference between just lifting off the throttle and adjusting the throttle

Let's take a moment to clarify - I'm not new to RWD and all of my RWD cars have been used even in snow. I'm aware of lift off oversteer but that's not what I'm reporting here. It's the roadholding. There's too much of a tendency to bite in constant corners with such small throttle adjustments that the selected gear makes no difference

Anyhow the other guys have got the hang of what I'm saying and I'm going to ask *** what settings she's using for the geo and pressures

Do you really need anyone's advice here?

 

[WILDASP]

Yep, it is pretty chilly at times around here, below 10 degrees C a lot of the time. The Dodge has felt unhappy in warmer temperatures too though... Do you guys find the grip really drops off in the wet?

Wet? No. Cold, (below 45F) yes. Cold AND wet, YES! There's a reason Michelin does not recommend PS2's for winter driving...

That said, I'd bet you also have an alignment or suspension issue, if the car is as squirrelly as you're describing when driven sensibly on dry pavement, especially in warmer conditions.

 

[slysnake]

The kiddo above [who recommends pernellis] is also off on his Michelin analysis. He must be thinking about the Sport Cup as he wrote in error x 2. Disregard for your sanity and safety.

Well' I did preface it with a statement that I didn't know what I was talking about. Also, I didn't recommend pernellis, I just said that I thought they had different tread options.

 

[ViperGTS]

>>>Do you guys find the grip really drops off in the wet?<<<

Are you serious?

 

[georgethedog]

I think even with a perfect allignment as recommended above (which is a great recommendation from people that know more than I), the Viper is not a cold/wet condition car in my opinion. Too much torque--tires too wide. I don't even think it is a good car in wet after being stuck driving it this summer during a rainstorm that started when I was in a parade with it. Do yourself a favor, park the Viper until temps reach 50+ and buy yourself an old Mr. Bean car (Mini for those who are Mr. Bean impaired) for the winter. Good luck.