02 ACR -v- 911 GT2 SPANKED in Sports Car International

[Tom and Vipers]

They spanked Viper pretty good:

At Thunderhill, Viper 2:05, GT2 "knocking on 2 min barrier"

Viper criticisms:

BRAKES
COOLING
Squirrelly ("You jump from 8/10s to 10/10s without really expecting it.")

"The GT2 is a car that feels like it was developed on a racetrack, whereas the Viper feels like a car that was built for the street, not as much for the track."

"You can drive the GT2 as hard as you want and it doesn't overheat, the brakes don't go away - it was just a very willing participant. Whereas with the Viper, we pegged the temp gauge, the brakes would go away after just a couple of laps and it's 43 deg today. ...So I'm not impressed with it as a track-ready car."

"...if DC is going to sell an ACR package for the Viper, shouldn't it be able to, well, race?"

"... When you drive the Viper, it feels like the suspension guys never talked to the brake guys and the brake guys never talked to the power-train guys. So there's this disconnect - it doesn't feel like the pieces are that happy working together. To that end, the Porsche feels like it was made out of one piece and the Viper feels like it is much more of a kit car - a car that was cobbled together."

"If you think our Porsche-racing ex-BMW team driver is just a German car snob, you should hear him praise the Chevy Corvette ZO6 - he is not someone who dismissed American iron out of hand..."

=============================================================

Actually, I was thinking the brakes and cooling can be fixed - however, it should be some kit provided by Mopar that is fully integrated.

As for the handling, Vipers are squirrelly and have any of the racers fixed that problem?

Inquiring minds want to know!

Regretfully,
Tom

 

[toddt]

I have to agree with the article. I don't think the 99 ACR is a great track car "out of the box". I still haven't found a suspension setting that doesn't feel light in the rearend--squirelly, as they said. The car is skiddish in the turns. The brakes are vague--soft, and the car doesn't brake nearly as well as it accelerates.

Having said this, these are fixable flaws. Perhaps all can be fixed for well under 10,000 dollars.

Stoptech brakes all around, MAYBE new shocks,(or a more able tuner than me).

I shouldn't be scared driving hard down norris canyon road (a twisty narrow road near my house), but I am, for the above reasons. My suspension isn't "compliant" as PMUM pointed out his was. The chassis is not soaking up the bumps, it is bouncing off of them, causing the rear to loosen way too much.

 

[Bill Pemberton Woodhouse]

Zzzoh, da girlymen at das U-r-peeing Maagazin, r zayyin dat ze Porch ist gefaster, und moor sivellized, vell, poppykock. Vipers r fur reel men under gorgeous vimen, dat kan drivin das Grosse Snake,mit der enjin inn das proper placz. Giv das Snake an eggstraw $100,000 grand und it vill nihilate das squashedundflattened Beetle spurtzkar, und den zzum. To gefahren einen Viper at 10/10ths may taken longermachen, but das ist das beautee ov zee svelte hunknee ve all driv!!! Sew yu kan go fastur zooner in a Porch mit gegigantickus price tagg, einen GTS vill revard you vit moor challengin gefahrten, und moor volks czeching u owtt!!

I vote fur das **** Serpent, und poo-poo on das Pooch, or wassever day ist callin it.

Danke Schon,

Das Vipermeister

 

[ViperGTS]

Bill, your German (?) is excellent!

 

[SPARKY]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MarkusReinhardt:
Bill, your German (?) is excellent!

<HR></BLOCKQUOTE>I DONT REALLY CARE WHAT IT DOES ON THE TRACK. IF I WAS GOIN TO RACE CARS ON THE TRACK, I WOULDNT RACE A PORSCHE OR A VIPER. ID HAVE A PROFESSIONAL BUILT CAR JUST FOR THE TRACK NOT THE STREET. THER ARE 100'S OF CARS BUILT FOR RACING THAT WOULD SMOKE EITHER ONE OF THEM. I BOUGHT A VIPER FOR THE LOOKS(94RT10). EVERYTIME YOU SEE A PORSCHE DRIVE DOWN THE ROAD NOBODY EVEN TURNS THERE HEAD ABOVE THE AGE OF 5!! WHEN I GO DOWN THE ROAD IN MY 94 RT10 GRANDMA AND GRANDPA GET WHIPLASH!! BESIDES THE PORSHCE HAS LOOKED THE SAME SINCE 1958!!!!!!!!!!!!HA!@!

 

[John ACR]

Sparky,
Well said.
My exact feelings.

 

[Snakester]

If the GT2 wasn't almost $100,000 more money, and the test wasn't done by a driver who races Porsches professionally, I'd say it was a fair comparison.

People who regularly race their Vipers are going to add a better radiator and PS cooler, put on new brakes/pads, probably tweak a bit with the suspension, and maybe replace the body panels to shave 250lbs off of the car.

These goodies will add maybe $10K-$25K to the price of the Viper and make it into a car competitive with the GT2 for about half the price.

All that test showed was that for 3X the price of the Viper, the GT2 is a better factory-stock racecar. I wonder how the test would have been against the comparably priced 911?

On the road, I do like the looks of the GT2 (not that I've seen more than one so far) but I do think that the Viper looks much more exotic, and is roughly as fast in the real world.

It will be interesting to see a rematch against the SRT-10, which in performance, balance, and braking, should be closer still to the GT2 on the track.

 

[Mike Brunton]

It does kinda **** that DC doesn't seem to really spend much time or effort fixing the known problems with Vipers... is this due to limited development funds? I don't know.

What really changed from 96-2002 on the Viper? 96 to 97, nothing really.. just little maintenance updates. 97-98, they put a pebble grain dash, airbag shutoff light, alarm shut-off, and tubular headers. Not much for a whole year of development. 99 saw 18" wheels and new tires, AL trim rings and a different shifter. '00 had the redesigned engine for NGR fix, and 01 had ABS - nothing new for '02.

In all that time, it doesn't seem like they did a heck of alot. They really should have fixed the brakes by 98, and why do the pedals still rattle at anything less than full up or full down? Sidesills still yellow (long-standing complaint), the car has always been somewhat skittish at the limit, and they coulda put on a nicer exhaust system.

I hope they have really worked the bugs out of the SRT, because I don't think it will change very much at all from it's into unitl it's end-run.

 

[Frank Parise]

Most of the Viper Racing League cars were consistently under 2 minute lap times at Thunderhill during the March Viper Days event, some were 5-6 seconds per lap faster. These cars have stock motors with headers, stock drivelines, upgraded brakes, and aero. They are built for far less than the cost of a Porsche GT2.

Toddt....the shocks on your ACR are easily adjustable for the condition you described. You need to soften the bump settings on your rear shocks and they will absorb the bumps rather than crashing over them. Your car should not feel skiddish under any circumstances. To adjust your shocks where you want them, here's what I would do:

(1)Set the bump and the rebound to full soft on both front and rear shocks. Drive around to get the feel of the car. This is probably where you want the shocks for street driving.

(2)Leave rebound settings on full soft and stiffen the bump settings by 2 clicks on both front and rear. Continue stiffening the bump settings by 2 clicks until the car is crashing over the bumps in the road or the ride feels too harsh for your liking. When this happens, soften the bump by one click. If it's still too harsh of a ride, go back another click to the soft side, etc. and stop adjusting when you are happy. You may find that the bump settings you like are different from front to rear. It wouldn't surprise me if you end up with the rear one or two clicks softer than the front.

(3)With bump settings fixed where you like them in step 2, begin stiffening the rebound by 2 clicks at a time. The rebound will mainly effect the amount of body roll (stiffer is less body roll). Keep going stiffer by 2 clicks until you don't like the feel, then back off 1 or 2 clicks. Again, you may like different settings in front than in rear.

Spend some time learning how to adjust the shocks to your style of driving and the dividends will be huge. They will significantly change the feel of your car. This should be done on a track rather than the street, so you can drive the car closer to its limits.

For the street, you would probably be happy to keep all the settings (both bump and rebound, both front and rear)on full soft.

Hope this helps. Good luck.

 

[joe117]

I'm not upset by the criticism of the Viper compared to the Porsche. I never drove the Porsche, of course, but I would expect it to be all he said. Porsche has always been known for cars that can handle and this one is a very expensive, well engineered Porsche. The Viper is probably all he said it was. Is that news to anyone? It seems to me that the Viper is not nearly as sophisticated as the Porsche and it's more of a brute force machine.
I'll bet that the Viper was designed to sell for a target price, look the way it looks, have lots of power from an exotic engine, handle and brake, in that order. I love my 94 but I know what it's really for.
I agree with Sparky. Only a Porsche nut will notice your Porsche. Almost everyone will drop their jaw when they see your Viper. Almost everyone just assumes that your Viper is faster than anything they have ever seen. You never have to tell anyone that it's fast. It's a super street car. That's what it's for

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Frank Parise:
Spend some time learning how to adjust the shocks to your style of driving and the dividends will be huge. They will significantly change the feel of your car. This should be done on a track rather than the street, so you can drive the car closer to its limits.

For the street, you would probably be happy to keep all the settings (both bump and rebound, both front and rear)on full soft.

Hope this helps. Good luck.
<HR></BLOCKQUOTE>

Frank--thank you a TON for the constructive help. I'm afraid that on this board, if you say anything negative about our beloved car, some types start mumbling about you.

I'm going to try your bounce-first method of adjusting tonight...

I'll definitely report back and even edit my posts if I can sort the car out!

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117:
Porsche has always been known for cars that can handle and this one is a very expensive, well engineered Porsche....It seems to me that the Viper is not nearly as sophisticated as the Porsche and it's more of a brute force machine. <HR></BLOCKQUOTE>

Dittos to everything you said, Joe--

I'll add this, though--for my friends that have purchased porsches (4 friends total), they have all said, to a man, that the car was LESS sophisticated than they expected...

Not trashing them, mind you, just reporting their takes.

 

[garolittle]

Oh yeah!!! Well, Vipers attract more chicks! Take that all you Porsche folks.

 

[Tom and Vipers]

Bill Bill Bill!

Das ViperBootCaptain!

Der Squashedundflattenedsoopindupin Beetle .... HA HA HA HA

I laughed and laughed and laughed!

GREAT POST!

 

[Chuck 98 RT/10]

Those comparisons are fun to discuss but they never bother me.

For me, the Viper is perfect, the Porsche is not.

 

[Tom and Vipers]

Regarding shocks.

Decades ago Monroe made a 500 shock that was massive. Something like 1 3/8 piston and 1/2" shaft.

The neat thing about this shocks was the bump was fairly soft but rebound! ...rebound was so stiff you could hardly extend the shocks by hand.

What that did to handling was impressive.

I have always been a BIG advocate of tons of rebound. For one thing, when you transient into a corner, the stiff rebound won't let the inboard side lift.

================================================

Regarding brakes and cooling. Frankly, a freshman auto engineer could do a better job on what is in the Viper.

Why in the world was such a bad job done? It doesn't make any sense.

 

[Tom and Vipers]

...and why doesn't MOPAR have the "fixes" for these problems?

What would be nicer than buying 3 part numbers and having your 3 problems solved?

 

[joe117]

I think DC has been spending all their "Viper Project" money on the bringing the new V2 Viper to production. I'm thinking they probably spend very little time, read money, trying to improve the V1 or V2 on a test track. To DC, the Viper is just an advertising tool. The idea that it might be a world class, production race car is not one of their goals. How many "handling/breaking" part numbers could they afford to spend time developing? They are only building a small number of these cars. How many improvement packages could they hope to sell? I think they design the car, build the car, and hope for the best. A problem would need to be major before they would change anything.

 

[SPARKY]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117:
I think DC has been spending all their "Viper Project" money on the bringing the new V2 Viper to production. I'm thinking they probably spend very little time, read money, trying to improve the V1 or V2 on a test track. To DC, the Viper is just an advertising tool. The idea that it might be a world class, production race car is not one of their goals. How many "handling/breaking" part numbers could they afford to spend time developing? They are only building a small number of these cars. How many improvement packages could they hope to sell? I think they design the car, build the car, and hope for the best. A problem would need to be major before they would change anything.

<HR></BLOCKQUOTE>SLF

 

[dadsvpr]

lets not forget that the gt2 is truly considered a track ready sports car as opposed to a club racer a more fair comparison imho would be against a mustang cobra r. also the gt2 "package" adds $60K over a $120K turbo, i know with simplified drive train (2 wheel vs 4 wheel drive) and high tech brakes. A more fair comparison would be a stock turbo or i beleive there is a GT1 that is a non turbo car.

yeah the brakes **** on the stock viper as does the gearing and weight, but i think with the right touch the acr suspension is a worthwhile package. and of course who can complain about the hp and torque?

Jason

 

[KenH]

I think the main criticism of the article is with the ACR which is suppose to be a track prepped upgrade to the Viper GTS just as the GT2 is for Porsche.

DC spent the $10K-$15K upgrade on nice looking cosmetic rims, adjustable shocks that I am not sure have ever proven to be actually superior to the stock GTS shocks on the track (I could be wrong, but have never heard a comment to the contrary), smooth tube upgrade worth about $150 and 5-point harnesses which don't necessarily keep you safe on the track. They also delete the air and radio to save weight, which everyone then pays extra to have put back in, so there is no significant weight savings other than perhaps a little in the rims.

That money should have bought track worthy brakes, brake ducts, a little more HP than just the smooth tube upgrade, a little less weight and the other things that actually make you faster going around the track. You buy a GT2, you know you are going to go around the track faster than a 911. You buy an ACR and do you actually go any faster around a track than a GTS stock for stock?

--- Ken

 

[Jim Hodel]

I'm fine with the adjustable suspension on the ACR, but Dodge should have also upgraded the brakes.

As far as a comparison to a Porsche GT2 goes, it's reassuring to know that you really do get something extra for the additional money you'll spend on the Porsche.

I thought the article was kind of a hatchet job on the Viper. I suppose they'll compare it to the new Porsche Carrera GT when it comes out.

Jim

 

[Butch The Snake]

Being an X-Porch owner fanatic you can not make a fair comparison between these 2 automobiles.

The GT 2 is a very limited production that has appreciated in value. List price $175,000.00 market price $225,000.00-275,000.00, you can buy 3-4 ACR's for this price. Because of the difference prices with these cars this comparison stops here.

If Dodge spent this much money on a Viper it would kick this GT-2 a**. Porsche has the worst customer service and has no loyalty toward it's customers. Previous Porch's:

87 911 turbo
91 911 turbo
96 911 twin turbo
98 Boxster
99 C4
01 996 twin turbo
GT-2 ordered-cancelled
GT- Carrera ordered-cancelled

I would never own another Porch as long as I live!

-----------------

01 GTS (10.90 e.t.@ 131 m.p.h.)

upgrading brakes
01 BMW M3 (good road course car)
01 740i sport
02 360 Modena (great road course car)
02 Escalade 22" DUB wheels (cool standing still)

 

[Frank Parise]

Tom, I believe that an ultra stiff rebound setting on the shock will do exactly what you said you don't want. It will lift the inside tire in a turn.

It would be interesting to have a thread on shock absorbers and how they work.

 

[Tom and Vipers]

Frank,

I guess the stiff rebound that I was talking about was the Monroe 500, which will impressive, is still a passenger car replacement shock - but a HD one.

Is it still the rule that the good handling BMW sedans lift that inboard front wheel? ...or *** that last decade's hot setup.

Actually, I've thought about weight transfer in a curve. Here are some thoughts:

1) For a single axle, the weight transfer from inboard to outboard is determined by the height of the CG, Hcg.

If Hcg is 0, then both wheels have equal vertical loads.

When Hcg is typical, assuming infinite friction, weight transfers outboard as speed increases until the inboard load goes to zero. From there, we roll over.

2) While roll centers, the resulting roll axis, and the position of the CG determin how the body will lean in a corner, RC does not affect Hcg and hence this weight transfer.

3) 2 axles share the burden of supporting the vehicle mass at the CG.

If the CG is midway between the axles, then everything in 1) applies to each axle for 1/2 the mass.

If the CG is closer to one axle, then that axle must react more mass and hance sees more weight transfer. There is no way around this.

4) Sway bars can be used to balance the weight transfer between the axles.

However, THIS IS WHERE IT GETS FUZZY FOR ME.

FOR EXAMPLE: If you have a big engine on the front axle, the car usually pushes, even with the heavier springs necessary to support the added weight.

To produce oversteer, you
ADD roll stiffness to the REAR, or
SUBTRACT roll stiffness from the FRONT.

The above REDUCES the weight transfer on the FRONT axle and
INCREASES it on the REAR axle.

I suppose since the rear axle is so lightly loaded, it's efficiency is not an issue - the "inefficiency" of the front axle is the focus.

While you can balance the car, you cannot utilize the full potential of the tires, so the car's handling is compromised.

A BIZARRE EXMPLE is a tricycle where the front wheel has ZERO roll stiffness.

Anyhow, my head hurts and my fingers are revolting! (ugly that is! ha ha)

Tom

 

[Toronto_ACR]

Can someone tell me what the times would be if the Viper ACR raced against the 911 Turbo or the Corvette Z06, or even a ferrari. Is the ACR superior to the 911 turbo. Does anyone know about this

thanks

 

[Guibo]

Hard to say for sure, but I'd think the Viper would be faster and here's why:

1) The article in question actually says Van Overbeek finally managed a time of high 2:04's at Thunderhill in the Viper. At this very same track last year, R&T guest test driver Steve Millen pulled off these times:
Z06 (385-hp): 2:08.39
996 Turbo: 2:10.73
[I know, different drivers and different dates. But really the gap between the Viper and the others is quite large.]

2) The 996 Turbo was beaten yet again by the Z06, the 405-hp version in C&D's SuperTuner Challenge article from 9/01. This leads me to believe that the Z06 is more than capable of beating the 996TT on any given day, at any given track.

3) The Z06 has been beaten twice by the Viper ACR.
Once in a Car & Driver comparo: http://209.11.44.65/xp/Caranddriver/comparisontests/2001/February/200102_comparisontest_yankeeboomers.xml
And then again in an edmunds.com comparo: http://www.edmunds.com/reviews/comparison/articles/45197/article.html


But that was the old Z06, which lags behind the new one to 150 mph by a rather signficant 3.9 seconds, by C&D's numbers. The 405-hp Z06 does the 0-150 sprint only 1.6 seconds slower than the Viper. That's a huge improvement. And its brakes are improved over the old Z06 as well.
Then again, niether of those Vipers that beat the Z06's had ABS, which they do now, so...

 

[Frank Parise]

Tom,
Here's my understanding of how all this works. Lifting a tire off the ground is not the fast way around the track. Wherever on the track this happens, you are losing time. The teams you are seeing do this have either not figured this out, or they have decided that the compromise in traction at that point in their lap is more than made up by time gained elsewhere on the track with this set-up. Usually this condition indicates a sway bar that is too stiff. While a sway bar reduces body roll, it actually lifts the inside tire in a turn, which is a bad thing.
The amount of lateral weight transfer is determined by (1)cornering G-force, (2)center of gravity height, (3) weight of the car, and (4)track width.
You are correct that increasing roll stiffness on one end of the car will result in a greater percentage of the lateral weight transfer taking place on that end. However, you increase the relative roll stiffness by going to stiffer springs or thicker sway bars, not by adjusting shocks. Sometimes increasing the roll stiffness on one end of the car will actually improve traction on that end of the car relative to the other end. Therefore, there are circumstances where you could stiffen the rear and actually reduce an oversteering tendency.
The shocks control not how much, but how quickly the weight transfer takes place. If you want weight to transfer onto a tire more quickly, stiffen the bump control on that shock. If you want weight to transfer off a tire more quickly, stiffen the rebound on that shock.
So, if your sway bar is too stiff and the rebound setting on the inside tire's shock is set too stiff, that's the easiest way to pull the inside tire off the ground during cornering, assuming all other factors remain equal.

 

[Robert Dyck]

Originally posted by Tom and Vipers:
They spanked Viper pretty good:

At Thunderhill, Viper 2:05, GT2 "knocking on 2 min barrier"

=============================================================

The GT2 "knocking" on the 2 min barrier? Was it 2:01? What was it?

Is a .04 such a huge difference?

 

[Guibo]

Yeah, the article was pretty vague, in terms of definitive lap times. In the final paragraph, it states

"Johannes managed to lap Thunderhill in just under two minutes in the GT2, while the fastest time he set in the Viper was in the high-2:04 range."

4 seconds is a pretty significant margin here. It's safe to say that at most tracks, the GT2 would probably show its heals to the Viper. Of course, the driver might make the difference. A person accustomed to driving Vipers professionsally (and not Porsches) might have those lap times reversed.
I think Paul Mumford (with a Viper rated at "over 500 hp") was running in the 2:02's at the Open Track Challenge event there last month. He might have been using Pirelli M+S tires, I'm not sure.