Does a front splitter reduce understeer on a stock GTS?

[Detlef]

Disclaimer: I am not an expert in anything related to downforce, suspension, tires ...

So with all the recent threads about installing front splitters on a stock GTS fascia, does a front splitter reduce understeer on such a street (versus track) car driven on a roadcourse? Thinking with more downforce, it should grip better and hence reduce understeer in fast corners.

Or am I misguided?

Neophyte mind wants to know.

Be gentle

 

[Dave's Big Brakes]

Hey Detlef,

You need to do splitter,wing, and canards, side splitters or your aero goes to crapola That's why the comp cpe & now the ACR's are so good.

Big Brake Dave

 

[dave6666]

Someone say WING?

 

[eucharistos]

mmuuuuhhhahahah

 

[Paul Hawker]

Best way I know of for a street car to reduce understeer on a street viper is to install 315 front tires on properly sized wheels.

Just a front splitter will have you constantly having variable understeer depending on air speeds, cars in front, angle of car etc.

Will oversteer/understeer differently depending on your speed in corners.

 

[JonB]

Does a front splitter reduce understeer on a stock GTS? Disclaimer: I am not an expert in anything related to downforce, suspension, tires ...
So with all the recent threads about installing front splitters on a stock GTS fascia, does a front splitter reduce understeer on such a street (versus track) car driven on a roadcourse? Thinking with more downforce, it should grip better and hence reduce understeer in fast corners.
Be gentle

Detlef: That is EXACTLY one thing that a front (and rear) aero-devices can do. But they need airspeed to work! And the results vary as speed varies.

Front (and side) SPLITTERS help divide (split) the arflow to minimize and eliminate LIFT. and minimize DRAG. While technically this is not CREATING RAW downforce, the net result is the same: More grip.

The adjustable airfoil BLADE of the ACR Front Splitter device (for example) can be adjusted to increase or decrease downforce. Adjusted wrong, it can create LIFT and launch you. It is not to be trifled with. And should NOT be used at high speeds without a balancing rear downforce device.

Canards, or Dive Planes, create true downforce (and drag), giving the tires more grip.

Sidesplitter 'skirts' divert air from spilling up along the sills and doors and creating rear wheel-well drag and lift. Again, minimizing LIFT is virtually synonymous with creating downforce. But it varies with speed. And the it can 'disappear' at certian speeds!

Rear Diffusers DITTO...they prompt the air to stay low and away, eliminating the vacuum pocket 'void' in airstream aft of the car.

Paul's hint to imnprove your CONTACT PATCHES first is valid...and that starts with stickier rubber AND a performance alignment.

Trivia: The 1996 GTS was the first to employ several air-dam aero devices under the front fascia, and the Cam-Tail spolier to 'balance' them at the rear. THis greatly improved the CD and top speed of the GTS vs the Gen 1 "Flying Bricks"

Was I gentle enuf (you clueless old thin-air-sucking rookie?!)

 

[TexasPettey]

Where in the turn process do you feel the understeer? What speeds are you sustaining in the turns when the car is pushing? Those will probably determine if aero would help.

If the car seems to understeer right at turn in, a bit of TOE out on the alignment is probably the best thing. That's largely a responsiveness item.

If the car is pushing while in the turn, some front aero would likely help if the speeds are higher (70MPH or above I would guess). You would probably get more impact from larger tires and more negative camber. If you pull the sport shims, you'll get negative camber and toe out for free. You can put them in and out to see how you like the feel.

The last thing to consider is some driving technique. If the front end is pushing in the corner, you may be able to add throttle. This will depend on the car setup and the type of turn you are in, but the idea is to gently rotate the car into position. It will seem a bit counter intuitive, but it does work.

You can also trail brake to add weight to the front tires in the turn and lift up the back end. This is pretty advanced, and the back end will feel very loose. I'd work up to this on a Viper, because it's hard to get the feel right. The back end sliding around at speed in these cars is a harrowing at speed. (At least it feels that way for me.) When you don't have it right, the car will likely spin on you.

 

[Paul Hawker]

Texas.

Thanks for reminding us about the sports shims on the front suspension of Gen lls.

They are pretty effective in enhancing turn in significantly.

Just do not forget to put them back in after the track event, or your tires will wear funny.

 

[GTS Bruce]

An agressive street alignment using stock tires can cure the understeer. Lowering springs and adjusted shocks help too. Also tire pressures. GTS Bruce

 

[Detlef]

Wow, lots of advice. Sounds like I shouldn't bother with aero stuff unless I do it all around, althou I may do the winglets (at least for looks). The sport shimm removal sounds interesting. Did a search and it resulted in conflicting opinions for track use. The manual also states for autocross use only. Our new track is 2.55 miles long and the sport shimm removal may not be appropriate for it. Since I drive my car way more on the street and plan to do 1-2 track days per year, not sure where to go from here.

Thoughts?

 

[TexasPettey]

The sport shims are interesting just in the fact that Dodge thought to put them there. The 'autocross' statement is a CYA statement. I doubt they could get any statement about closed course race tracks past the attorneys. I'd be interested in what they say about the stuff on the ACR, if they even do.

I think that if you are looking for a quick, easily repeatable way to change between track & street alignment up front, sport shims are the way to go. If you don't mind street driving on an agressive alignment, it's easier to just leave the car's alignment set up for the track. If you're only going to do a track event per year, the sport shims and a good agressive street alignment would probably be your best bet.

That said, taking the shims in and out is a bit of a PITA. It's not something you'll want to do often. If you're not a DIY person, you won't want to touch them at all. Depending on your tools, you may have to remove the upper shock bolts and lean the shock out to get to the upper control arm support bolts.

That looks like a fun track. Better think about those brakes if you're going to do that course regularly. The speed on those straights in close proximity to the 180's will make for some serious brake fade. Definately invest in brake lines, some cooling, good pads, and good fluid.

 

[Detlef]

Thanks TexasPettey, the PITA statement sounds right from reading yours and others experiences (yes I do use the search function) with removing/re-inserting them. I drive to the GTS to/from the track event and this would mean bringing even more tools, and now also a jack with me for this removal procedure. Since I do track days for fun only, I think keeping things stock is probably the best compromise for me. Time to start saving for a used track only car.

Fortunately, I've got the brakes covered with Dave's Big Brake kit and SRT hardware from PartsRack on all fours:

 

[TexasPettey]

That's a sweet looking car, and nice brakes!

You can do the shim swap at the house and drive to the track a couple hundred miles of street driving with extra camber won't hurt the tires.

 

[dave6666]

Best way I know of for a street car to reduce understeer on a street viper is to install 315 front tires on properly sized wheels.

And what are the correct sized wheels for 315's? 11" wide is like max right?

 

[Detlef]

TexasPetty, you asked where in the corner I feel the understeer and it is once I am in the turn, not a the beginning, so I find myself having to slow down more prior to turn-in. Can't wait to try my new brakes, the track opens next month

 

[JonB]

The sport shims are interesting just in the fact that Dodge thought to put them there. ..................That looks like a fun track. Better think about those brakes if you're going to do that course regularly. The speed on those straights in close proximity to the 180's will make for some serious brake fade. Definately invest in brake lines, some cooling, good pads, and good fluid.

The Cone Cooling Kit is a well-engineered addition to Gen 2 for little money.
far more efective than the Porsche Brake Baffles, but CAN be used in conjunction with them!

Trivia.... back in 1993, Grailkeeper Herb Helbig first told me about the shims for Autocrossing and short-tracking.... (Gen 1-2 only) They are an amazingly-simple handling top-secret. !!

 

[Chuck 98 RT/10]

Wow, lots of advice.

Yup. It never ends. Just when you think you have it figured out the track changes or the weather changes or the tires change or, etc...it never ends. You just do this or that and keep trying new stuff. If you have a huge bank account you can hire a team like the pros do, and even those guys are tweaking all the time.

 

[Chuck 98 RT/10]

The Cone Cooling Kit is a well-engineered addition to Gen 2 for little money.

Should be on the list of first mods for any tracker. The Cone kit and a bottle of Castrol SRF and you'll never have to worry about brake boil.

 

[Boxer12]

Don't leave it alone, slam it! Also, make sure you don't roll on old tires. They get you there fine, but **** big time on the track. When they give away, the armco will catch you in a hurry. You want to stay off the armco. Have fun!

 

[Boxer12]

Did somebody say trailbraking?

 

[TexasPettey]

TexasPetty, you asked where in the corner I feel the understeer and it is once I am in the turn, not a the beginning, so I find myself having to slow down more prior to turn-in. Can't wait to try my new brakes, the track opens next month

This actually sounds like a very safe condition for learning to me. If you add too much front tire, you'll have a lot more tendency for the back end to come loose first. That is often a harder scenario to correct than the front pushing. I would tend to suggest using driving style first before adding more to the car.

Here's a link that gives you a bit more on the use of throttle for understeer correction. Since we have so much torque on our cars, it doesn't take 'stomping the throttle' to induce oversteer.

Revisiting understeer - Greg Reinacker’s Weblog - Musings on just about everything.

As you look online and get advice from folks, remember that there is a big difference between AWD, FWD, & RWD as it pertains to throttle use.

 

[Detlef]

This actually sounds like a very safe condition for learning to me. If you add too much front tire, you'll have a lot more tendency for the back end to come loose first. That is often a harder scenario to correct than the front pushing. I would tend to suggest using driving style first before adding more to the car.

Here's a link that gives you a bit more on the use of throttle for understeer correction. Since we have so much torque on our cars, it doesn't take 'stomping the throttle' to induce oversteer.

Revisiting understeer - Greg Reinacker’s Weblog - Musings on just about everything.

As you look online and get advice from folks, remember that there is a big difference between AWD, FWD, & RWD as it pertains to throttle use.

Good article. This is exactly what Skip Barber has taught me in their course. Slightly back off the throttle instead of steering for corrective action. It does work well.

 

[Dave's Big Brakes]

Hey Detlef,

You'll do better buying race wheels, your oem's limit what you can do. Plus your oem's weigh a ton Get a set of SSR & Kuhmo's you'll get more bang for your buck.

Big Brake Dave

 

[Detlef]

I hear you Dave. That's a bunch of $$$, darn stuck market. Also, I hear the 18" SSRs don't come in Silver anymore, only Black and Anthracite.

 

[PS78]

That's a sweet looking car, and nice brakes!

You can do the shim swap at the house and drive to the track a couple hundred miles of street driving with extra camber won't hurt the tires.

?so would the effect on toe after removing the shims, as indicated in the 2002 manual, actually benefit the viper's cornering performance?...or is it best to get hold of a trammel(?) bar to correct the toe?
tks!