How much weight? How much money?

[Warfang]

Sorry, Lee - gotta disagree with you here. With Bob Lutz at GM, DC knew that there would be a concerted effort to beat Viper - if for nothing else - as a direct "screw you" for forcing his retirement - as he obviously had a few more good years left in him. I also happen to know that Mr Lutz himself was sending his own spy photos to the folks at DC and even some VCA'ers before the C6 was unveiled. He also arranged ot have a Z06 for Maurice Liang to drive at a west coast Viper Days - coincidence? I think not. The dry sump motor was a direct thumbing of the nose at Dodge for not doing anything to address the oiling problem on their "street legal race car"

These guys are a competitive bunch and they REALLY like to drop hints and play other minds games with the competition - it's guerilla marketing at it's finest - by manipulating the key players.

DC knew that it was coming.

While I agree DC knew it was coming, I don't think they knew how ugly it was going to hit them. So I'll give them a little time to catch up. If they dont... hello GR-1!

 

[Skip White]

How'd I miss this one.

Much good info has been said in this post. The titanium frame is out of the question. The market on this metal is at a record high at the moment. The frame cost would be way out of sight.

Don't think an aluminum frame is a bad idea. GM is not going to screw up on this.

As far as flexing, that's not an issue, as the alloy's used would not be your tipical 6061 but possibly a 7000 series aluminum. Aluminum frames are used on some of the finest, fastest cars in the world.

As for the wheels, tires, brake rotors, this is where one needs to start at, as well as the flywheel. The 41 lb battery can be reduced to 26 lb with a Hawker Oddesey battery, and get rid of the heavy battery frame. It should be plastic or aluminum. The seat lowering kit will save 4-5 lbs, and do a permanent mount setup on the passanger side, and save about 9 lbs. There are many items that can be lightend on this car, without noticing a problem. The seats them selves are very heavy. A 30 lb reduction could be acheived with a set of high quality street/racing seats if you included the track system.

Many more items can be lightend up on the car. Some will cost. I've allways said these cars are to heavy for what they cost. DC should have addressed this. GM did do this on Z06 and are doing it again on the new model.

I love the windage tray style oil pan on the SRT. I seen the inside of it,and it's a fine pan, but very heavy. It could have been thinner or made of Magnesium. No one mentioned Magnesium. You would be shocked at how light it is, and fairly strong. Porche and VW seem to have done well with it. I think the car needs to be around 3050 and not a pound more. I'd be happy to reach that, and not have to gut the car. Ford srewed up on the GT as it's a heavy pig for what it cost.

Oh, and if your like me,(thick) sliming down would be a huge improvement for us and the car.

ps, has anyone ever heard of hardbore or hardox steel? Now there's your answer to weight, cost, strength

 

[Chuck 98 RT/10]

Good points Skip. But Viper owners are the biggest whiners on the planet. Can't you imagine the comments?

"85K and these are the best seats they can get? ***?"
"85K and I can't even adjust the passenger seat? ***?"
"85K and a plastic battery tray? ***?"

They fall right in line with the current comments...
"85K and no TC? ***?"
"85K and no AS? ***?"
"85K and a crappy radio? ***?"

All I ever wanted was more HP, not that I ever complained about 500.

 

[Viper Specialty]

So where can I get a complete set of wheels and tires for 100#?

Catwood- I am assuming this had meant you would like to know where you can get wheels that will shave off 100#? The simple answer is I do not know of any wheels that will shave that much weight, which is why I had included Rotors in the equation as well. The Composite/AL rotors used on high-end Porsches would knock off almsot 80 pounds by themselves. The SRT rotors are approaching 40 pounds EACH, with their composite counterparts coming in at just over 20.

 

[Warfang]

How'd I miss this one.

Much good info has been said in this post. The titanium frame is out of the question. The market on this metal is at a record high at the moment. The frame cost would be way out of sight.

Don't think an aluminum frame is a bad idea. GM is not going to screw up on this.

As far as flexing, that's not an issue, as the alloy's used would not be your tipical 6061 but possibly a 7000 series aluminum. Aluminum frames are used on some of the finest, fastest cars in the world.

As for the wheels, tires, brake rotors, this is where one needs to start at, as well as the flywheel. The 41 lb battery can be reduced to 26 lb with a Hawker Oddesey battery, and get rid of the heavy battery frame. It should be plastic or aluminum. The seat lowering kit will save 4-5 lbs, and do a permanent mount setup on the passanger side, and save about 9 lbs. There are many items that can be lightend on this car, without noticing a problem. The seats them selves are very heavy. A 30 lb reduction could be acheived with a set of high quality street/racing seats if you included the track system.

Many more items can be lightend up on the car. Some will cost. I've allways said these cars are to heavy for what they cost. DC should have addressed this. GM did do this on Z06 and are doing it again on the new model.

I love the windage tray style oil pan on the SRT. I seen the inside of it,and it's a fine pan, but very heavy. It could have been thinner or made of Magnesium. No one mentioned Magnesium. You would be shocked at how light it is, and fairly strong. Porche and VW seem to have done well with it. I think the car needs to be around 3050 and not a pound more. I'd be happy to reach that, and not have to gut the car. Ford srewed up on the GT as it's a heavy pig for what it cost.

Oh, and if your like me,(thick) sliming down would be a huge improvement for us and the car.

ps, has anyone ever heard of hardbore or hardox steel? Now there's your answer to weight, cost, strength

Good points Skip. If they can make a good aluminum frame at a reasonable cost and can also be used in the verts, then I'm all for it.

I'm no engineer, but magnesium and oil seems like a potentially dangerous combination. Is this being done by other performance cars?

 

[steve911]

Actually,
the biggest drawback for Magnesium is it corrodes so quickly if not painted or very heavily annodized.

Magnesium works very well as a casting, but not nearly as well drawn into shapes that would be found in a frame. As a matter of fact we can all brag that we have magnesium components already in the car. The big dash support and part of the master cylinder support is a mag casting!

 

[SylvanSRT]

i understand that magnesium is also very brittle.

 

[Catwood]

So where can I get a complete set of wheels and tires for 100#?

Catwood- I am assuming this had meant you would like to know where you can get wheels that will shave off 100#? The simple answer is I do not know of any wheels that will shave that much weight, which is why I had included Rotors in the equation as well. The Composite/AL rotors used on high-end Porsches would knock off almsot 80 pounds by themselves. The SRT rotors are approaching 40 pounds EACH, with their composite counterparts coming in at just over 20.

I sort of said it in jest. The OEM wheel/tire combo is heavy. Real heavy. I pick up a tire the other day on my friends racecar and nearly threw it over my shoulder...LOL. I could actually hold it with two fingers. Now that wouldn't work on a Viper I know. I'm going to be changing rotors (and race pads) soon. I want a set of race rims. I'll try and find the lightest set I can afford.

 

[Kenny]

Actually,
the biggest drawback for Magnesium is it corrodes so quickly if not painted or very heavily annodized.

Magnesium works very well as a casting, but not nearly as well drawn into shapes that would be found in a frame. As a matter of fact we can all brag that we have magnesium components already in the car. The big dash support and part of the master cylinder support is a mag casting!

SRT-10 Valve covers are also magnesium.

Skip made some great points and I look forward to implementing some of his suggestions as I had not thought of them before.

 

[Skip White]

Actually Magnesium is very good in a cast form, and as Steve mentioned the viper's fire wall is made from Mag, as a matter of fact, it's the largest casting of mag ever used in an auto. As for the fire hazard, it's only vulnerable when in shaving or granulations, and powderd is the most dangerous, but in solid form, it's very safe. Yes it will corrode, but painting or powder coating would be the solution. No way for the frame. I didn't know the valve covers were mag.

I take back what I said about DC being behind the times compared to GM. The Viper doe's have some very good weight reduction going on, but we need more.

As for the lightest wheels out there, well that goes to the SSR comp wheels considering there low cost.

Mag is not brittle, but as I said it's not comparable to aluminun in equal volume.

Is it being used in performance applications, yes, VW blocks were allways mag. and possibly Porche.

The weight savings on wheels when using SSR comps, lighter tires, and at least a set of Stoptech rotors is nearly 100 lbs.

There is a new aluminum alloy on the market being used on driveshafts. It is said to not have the inherant fatiuge factors assosiated with aluminum.

Carbon fiber cost will come down in the future, as usage grows, and the fiber material, and resin compounds will become stronger. I love carbon fiber

 

[Catwood]

As for the lightest wheels out there, well that goes to the SSR comp wheels considering there low cost.

Do they make an 18" wheel?

 

[Skip White]

They only come in 18 for the Viper. I chose all 18X11's for my car, and went with 305/45/18 Nitto's for the rear, and a 10mm wider than oem for the front.

 

[Catwood]

ummmm...I'm currently running a 315 front. When I did a search I only saw 17" but they were 10# ligher than other wheels. I'll search somemore.

 

[Kenny]

As for the lightest wheels out there, well that goes to the SSR comp wheels considering there low cost.

Do they make an 18" wheel?

Skip, I thought I remember you saying that you were working on aluminum rotors for our cars---anything further on that? Barring their availability, are Stoptech's the lightest replacement rotor?

Also, I understand that our driveshafts are so short that CF replacements---although available---provide negligable perfomance improvement.

I found the reference to the valve covers being die-cast magnesium on page 14 of the SRT Powertrain Student Workbook.

 

[Skip White]

The guy that doe's the aluminum rotors has never got back with me. He even has a set of my oem rotors.

The C/F driveshaft ends up weighing the same as an aluminum, but is good for 1500 HP They really don't like making the C/F material in smaller diameter on thin applications. On longer driveshafts it would make a much better gain on weight savings. Non the less, a strong rigid drive shaft is valuable. I have a C/F shaft in my car. The aluminum end peices are massive compared to the oem shaft. The C/F material is much lighter but the heavy duty end pieces, evened the weight out.

 

[SylvanSRT]

i think you mean aluminum hats on the iron rotors will save lots of weight

 

[Kenny]

No, I thought that too at first Sylvan, but Skip apparently has a line on a guy making rotors out of a special aluminum alloy that can withstand braking temps.

 

[Viper Specialty]

No, I thought that too at first Sylvan, but Skip apparently has a line on a guy making rotors out of a special aluminum alloy that can withstand braking temps.

No, they were full aluminum rotors that had steel friction surfaces attached to them. I do not know whatever happened to this project though...

I have something else I will be working on this winter, if I can get costs under control that is in a similiar arena.

 

[GR8_ASP]

Hmm, in afterthought I think I have added a bunch of weight. 70 lbs or thereabouts for a Paxton, 40-50 lbs for a roll bar so I guess I need to find new ways to lower the weight lest the vette get to 650 hp and start to be a challenge

 

[Racer Robbie]

Congrats to everyone here. This is by far the best post ever. Great job Skip White.

 

[Thums Up]

It's simple put a $500 rear-gear in your SRT/Coupe and blow the Vette away. You have to factor in the vette starts with a 343 rear-gear. The Viper only has a 3.07

 

[Viperfreak2]

Has anyone ever proved a 355 gear makes the car accelerate faster? It might 'feel' faster, but I don't think it 'goes' any faster. I could be wrong...

 

[Kenny]

Has anyone ever proved a 355 gear makes the car accelerate faster? It might 'feel' faster, but I don't think it 'goes' any faster. I could be wrong...

From what I understand, the few informal tests that have been conducted have actually show a slow down due to traction issues and increased shifts. It is a 'fun mod', particularly on an otherwise stock car, but produces little fruit.

If, for instance one were to compare the Viper to the '06 Z06 as the gentlemen above did, you must keep in mind that although the Z06 has a 3.4x rear gear, because of a higher rev limiter the Z06 can do 0-60 without shifting out of first. Even with the stock 3.07, the '06 Viper (which reportedly has a lower rev limiter than the earlier Gen III cars) must make the 1-2 shift. In fact, many of the high hp cars go to a steeper gear like 2.73 to make the quarter without going into overdrive.

Additionally, traction is hard enough to come by in stock form on the stock run-craps. I can't see changing gears, but many swear by it.

 

[Skip White]

If memory serves me, the T-56 in the Vettes have a different gear ratio. This would change everything.

As far as the 3.55's being faster, it is, only if the traction is improved, (tires, road surface) and the driving skills would have to be much better, as the 3.55's run out of breath much quicker. The 3.55 does put you at a nice safe speed in third, when racing or sprinting about. There are many factors, but few will clock better times, due to there inability to shift quickly enough.

When the car has two good sized ocupants, this tends to bog the car down, when spinting around. The 3.55 would certainly give the car an advantage then.

 

[Vic]

355s provide more torque multiplication, good for lotsa grunt off the line. Like Skip said, if you've got the traction, this torque multiplication is useful. (oh no!, traction is a variable, that threatens our simplistic black/white, good/bad view of the cosmos!) Once the car is underway, 355s don't provide any more forward motion than shifting gears does, because as you run through the gears, the ratio between the engine rpm and mph reaches the same optimum potential, albeit in a new, now-higher-than-before gear. Only the initial motion of accelerating the mass from a standstill is affected.

Oh, I forgot to state the obvious, so here ya go.
You will have a lower top speed.
You will have to shift earlier, and may actually end up with a lower 0-60 time.
Since you have to grab 4th in the 1/4 mile anyway, it shouldn't hurt your 1/4 mile times.

 

[Chuck 98 RT/10]

355s provide more torque multiplication, good for lotsa grunt off the line. Like Skip said, if you've got the traction, this torque multiplication is useful. (oh no!, traction is a variable, that threatens our simplistic black/white, good/bad view of the cosmos!)

Oh no Vic!!! The Viper is too much of a beast already! I can't handle it! Computer assisted traction control is the only way anybody can drive this car. It's just tooooo dangerous.

For those unaware, the above comment regarding TC are completely sarcastic. Traction control belongs on Vettes, not on Vipers.

 

[Skip White]

Vic, I can't cross the line in third. I have to shift about 150 feet from the line, and this kills my time. I could probably coast and do better. The time to shift, and fourth gear has no power. My car is 175lbs lighter than stock, and has a handfull of mods, and this allows the car to redline out sooner.

As for the 3.55's they do actually pull harder in all the grears. This puts you at a higher rpm in every gear from where you were with the stock gear. Second and third are very hard pulling, and they don't acheive the same mph, at redline. All gears are closer in rpm diff. with lower gears. The fun part is from a rolling start, and going to second. The car will pull harder, but for a shorter time, before having to shift. Good traction makes the 3.55 a good choice, as a 3.07 will bog down on good pavement, unless you induce massive wheel spin. The Viper is far to heavy to use a 3.07 when drag racing. To be honest the manual trans. is what's hard to control, as they are so positive, you can't regulate the power, like an automatic, with a stall converter. Unless the tires give and slip a bit, the 3.07 will make the Viper fall on it's face. This is one time the oem clutch is a benifit, as it doe's slip under extreme load. Yes it doe's!!!

 

[Vic]

Skip, the part about it pulling harder in 2nd and 3rd is hard for me to understand. I can't argue with your personal experience, so I'll just kinda accept it for now, but here is where I part company-

Yes, you have a lower overall gear ratio, and that is immediately appearent when you step off the line. When you go to 2nd gear, you will not have a new overall gear ratio than you had before the gear swap!

Before the gear swap, just for the sake of argument, lets say you shifted out of 1st at 5500 rpm, then grab 2nd. When you arrived in second gear, your overall ratio (before swap) is apx the same as it would be in the bottom of 3rd {after the 355s were installed). What I am saying is, that any overall ratio you can end up having with 355s, (other than 1st gear), can be repeated with 307s, albeit not in the same gear. Another way of saying it is, maybe the top of 2nd with 307s is like the bottom of 3rd with 355s?

There is a way to prove this, by comparing teh overall gear ratios between 307 and 355, given the same T56 gearing. IF you put the two charts side by side, I think you will see that the 355s start lower, then there is an equal torque multiplication between the two ratios, until you hit redline earlier with the 355s, and the 307 chart keeps going until it redlines. So one (355) starts out lower, then tops out sooner, and the other one (307) starts higher, and tops out later. In between the two extremes there are overlapping and equal torque multiplication factors.

Tomorrow! Gotta go now!

 

[Vic]

Oh no Vic!!! The Viper is too much of a beast already! I can't handle it! Computer assisted traction control is the only way anybody can drive this car. It's just tooooo dangerous.

lol Chuck!

I'm scared to death of it! Gonna sell it for a C4. Comfy, and non-threatening!

 

[Thums Up]

Well, I happen to have had both. And, must say the 3.55 was the most fun. However, gear for gear, pound for pound. I don't care what gear you have in your car. The 3.55 out pulls the bone stocker in every gear. Simple physics says the higher the gear ratio the more revolutions turned for point (A) around the farris wheel. Excuse me, but isn't the point to keep the motor in it's RPM band. You simply can't do it with the stock gear as it will drop to much between shifts.

True enough, you had better know how to shift with 3.55, but I found that with basic mods and the swapping of taller tire sizes, the car will just walk away from the others.

My guess is that DC chose a lower ratio gear for better gas mileage and overall daily usage of the car. Now, if you compare a stock Z06 with a stock viper coupe whom both have the same gear ratio equally. Physics says the viper will pull away everytime. Even if the vette weighs less. Because it has more cubic inch (Motor). However, it is somewhat disabled because of the lacking gear ratio. 0.36 splines less than the vette off the starting line. Then factor in the weight difference between the two.