620 Roe GTS RWHP With 3.55 Gears..Need Input

[00prowler]

I am running 3.55 Gears in my Roe S/Cd GTS With fresh Pilots. I street drive it only. I took a former Viper owner friend out the other day and he felt the car would hook better (I agree) and pull harder and longer with the 3.07 gearing. When my car was stock the car felt sluggish with the 3.07s, and if I switch back I dont want to be disappointed. He also felt with the 3.55s the car goes to redline to quick with all the power I have. Which gears will pull harder from 80 mph on up? I love the high end pull... What do you think...Thanks...AL...

 

[1TONY1]

From what I have seen they pull about the same. This is with me racing an identical car with a good driver from a roll. I have 3.55's and he had 3.07's. If you have or can have Kumhos on the rear I would not change. It will still be better in normal daily driving with the 3.55's. The one reason to change.....if you go to the strip and have to make the 5th gear shift you would probably be quicker with 3.07's.

p.s. Either gear really needs Kumhos on the rear.

 

[rcdice]

I'm waiting and waiting and waiting for 3.33's to be available again. Supposedly been in the works for quite awhile by some sort of joint venture including Unitrax.

3.33's give you a little "something something" above the stock 3.07 but still allow some room in each gear. Perhaps ideal for modified, higher hp cars. FWIW, new zo6 has 3.42. Add a 100+hp, knock the gear back a notch and you have the same balance.

Anyone have any insight as to when 3.33's will be available? I've been told five months.

 

[00prowler]

Tony, how about top speed in 6th gear with this setup, can I hit the big 200 Thanks...AL

 

[PhoenixGTS]

I cannot speak based on experience with a high-powered car, but on my mild bolt-on machine the 3.55s allow for much better modulation of the throttle to control wheelspin than the 3.07s. It seams that once the car is spinning with the stock gears, lifting the throttle has kind of a delayed reaction in getting the tires to stop spinning whereas they will stop spinning much sooner after you lift with short gears. Perhaps it is because tracton loss is at a lower lower speed/higher rpm with short gears - I don't know - but 3.55s make for more effective human traction control. But put some Kumhos on that monster and own the street with your short gears.

 

[1TONY1]

Tony, how about top speed in 6th gear with this setup, can I hit the big 200 Thanks...AL

Your talking to the wrooong person I let off way before then. My opinion, with around 650 rwhp and 3.55's it should pull 6th gear. That's an opinion only.

 

[onerareviper]

I cannot speak based on experience with a high-powered car, but on my mild bolt-on machine the 3.55s allow for much better modulation of the throttle to control wheelspin than the 3.07s. It seams that once the car is spinning with the stock gears, lifting the throttle has kind of a delayed reaction in getting the tires to stop spinning whereas they will stop spinning much sooner after you lift with short gears. Perhaps it is because tracton loss is at a lower lower speed/higher rpm with short gears - I don't know - but 3.55s make for more effective human traction control. But put some Kumhos on that monster and own the street with your short gears.

SO TRUE!!! Stay with the 3.55 IMO.

 

[mntngts99]

I just went back to my 3.07s and now wish I hadn't. If my times don't come back down after I put the new clutch in, the 3.55s are going back in.

 

[00prowler]

I just went back to my 3.07s and now wish I hadn't. If my times don't come back down after I put the new clutch in, the 3.55s are going back in.

Can you elaborate why you wish you hadn't so i dont make the same mistake...Thanks...Al...

 

[mntngts99]

Well the 3.07s are harder on the clutch and now my clutch is slipping. After three years with the 3.55s my shift points are all messed up,shifts come a lot slower. I went from 1.5x 60' times to 1.7x 60' on pilots with the 3.07s and wheel spin is harder to control. I lost 4 tens in the 1/4 mile with the same tune but some of that is my clutch and relearning new shift points. The car just doesn't seem to pull through the gears as hard or as fast.

Just my .02

 

[00prowler]

Well the 3.07s are harder on the clutch and now my clutch is slipping. After three years with the 3.55s my shift points are all messed up,shifts come a lot slower. I went from 1.5x 60' times to 1.7x 60' on pilots with the 3.07s and wheel spin is harder to control. I lost 4 tens in the 1/4 mile with the same tune but some of that is my clutch and relearning new shift points. The car just doesn't seem to pull through the gears as hard or as fast.

Thanks for the insight Brad...Looks like your setup is close to mine..I dont have to worry about the shift in the traps, cause I dont track it anyways...What is your best MPH and ET with your Viper so far?...Thanks...Al...

 

[JohnnyBravo]

I just went back to my 3.07s and now wish I hadn't. If my times don't come back down after I put the new clutch in, the 3.55s are going back in.

Wow. That's almost exactly the opposite of what I was told.

When I asked around about doing gears, almost everyone said "if you're going to stick with the bolt-on stuff like headers, exhaust, rockers, etc, then the gears are a great mod. But if you're going to do a power adder like a blower or NOS, then leave the stock gears."

I probably heard that from 4-5 different people. The rationale was that with the additional power from a power adder, the 3.55's make so much torque that your lower gears become almost useless. I heard that you are basically grabbing for 2nd gear as soon as you leave the starting line at the track. Some told me that the car won't hook nearly as well. Some said that you may end up with an extra shift in the quarter mile. Some said it kills your fuel economy because 6th gear runs much higher rpms (although they said that it's an actual usable gear now).

I've got the blower on the car now, with the wather/methanol. The stock pilots are always pissed at me. They're worthless through all of 1st and almost all of 2nd gear. I just ordered some Kumho V700's from John B. at Partsrack, so hopefully that will cure some of my traction issues.

I am at the drag strip a LOT, so that's my primary concern. Don't care so much for road racing.

I'd really like to know more about the power adder/3.55 gear combo. If it's a good mod, I'll go get the gears, too.

 

[mntngts99]

Al
1/4 mile times to me are misleading. I run at a average altitude density of 5700' to 6200' so my times will be slower. My best time with 3.55s is 10.71 at 129.77 with a 1.46 60' on BFGs. I've also ran 10.8's and 10.9's at 131 mph also. With the 3.55s I'm only good for 132 mph at red line in fourth. I Just put on the Water/**** and after I get that program work out I will go to the 10 lb pulley, so that's why the 3.07s went back in. If I was going to stay with the 8 lb pulley or if I don't like the 10 lb pulley the 3.55s will go back in.

___________________________________________________________
I heard that you are basically grabbing for 2nd gear as soon as you leave the starting line at the track
___________________________________________________________

My first shift is at or just past the 60' mark.
On my BFGs in town with the 3.55s they would hook well for me. The first time out on the 3.07s the BFGs were pissed at me also in first and second gear.

 

[TOOOFST]

Tried them all at the track.All around I like the 3.33's.

 

[JohnnyBravo]

Any updates or additional opinions on the power adder + gear debate.

I've got the Roe S/C and I'm interested in getting down the quarter mile in the quickest time possible (in addition to the impromptu street races that occur from time to time). Pure straight line acceleration is my only concern.

Are the 3.55's a good addition if you are already making around 600 rwhp, or are they too much?

 

[Joseph Dell]

Can someone calculate red line in 4th gear with 3.33's? now i'm curious...

JD

 

[Blade Runner]

Red line speeds.
This is just an estimate.
3.07=150.203mph
3.33=138.475mph
3.55=129.893mph

 

[JohnnyBravo]

Here are some figures that I believe are relatively accurate

With 3.55's and Pilots

RPM 1st 2nd3rd4th5th6th
2000 16 24 33 43 59 87
2250 18 27 38 49 66 98
2500 20 30 42 54 73 109
2750 22 34 46 60 81 119
3000 24 37 50 65 88 130
3250 27 40 54 71 95 141
3500 29 43 58 76 103 152
3750 31 46 63 81 110 163
4000 33 49 67 87 117 174
4250 35 52 71 92 125 184
4500 37 55 75 98 132 195
4750 39 58 79 103 139 206
5000 41 61 83 109 147 217
5250 43 64 88 114 154 228
5500 45 67 92 119 161 239
5750 47 70 96 125 169 250
6000 49 73 100 130 176 260
6250 51 76 104 136 183 271


With 3.73's and Pilots

RPM 1st2nd3rd4th5th6th
2000 16 23 32 41 56 83
2250 17 26 36 46 63 93
2500 19 29 40 52 70 103
2750 21 32 44 57 77 114
3000 23 35 48 62 84 124
3250 25 38 52 67 91 134
3500 27 41 56 72 98 145
3750 29 44 60 77 105 155
4000 31 46 64 83 112 165
4250 33 49 68 88 119 176
4500 35 52 72 93 126 186
4750 37 55 75 98 133 196
5000 39 58 79 103 140 207
5250 41 61 83 108 147 217
5500 43 64 87 114 154 227
5750 45 67 91 119 161 238
6000 47 70 95 124 167 248
6250 49 73 99 129 174 258


Another quick comparison using only 6000 rpms

Gear Ratio and Top Speed Chart

1 2 3 4 5 6

3.07 : 58 76 114 151 204* 302*
3.31 : 54 70 105 140 189 280*
3.54 : 50 66 99 131 177 262*
3.73 : 48 63 94 124 168 249*
4.10 : 44 57 85 113 153 226*

I guess the real question becomes....what trap speed do you get with your mods? If you think you're going to trap over 130 mph, you might be better off with something smaller than a 3.55, because with a 3.55 you will proabably have to make an extra shift to 5th gear.

I could squeak through the traps at the top of 3rd when the car was bone stock with the stock 3.07's.

 

[GTSnake]

I think with Al's original question since he doesn't track the car that much and he has the blower he's better off with the 3.07. With more track time and more serious drag racing events the 3.55 would probably be better.

 

[IEATVETS]

I drove a SRT-10 with a Paxton blower and other mods that put down 705rwhp. He had 3.73 rear end gears and I loved it! I was shifting a lot but what a ride.

 

[Simms]

"The one reason to change.....if you go to the strip and have to make the 5th gear shift you would probably be quicker with 3.07's."

This is why I stayed with 3.07's.

 

[v10sloboy]

3.55 all the way I love them with my 8lb blower. On the street it is way faster then the 3.07

 

[JohnnyBravo]

3.55 all the way I love them with my 8lb blower. On the street it is way faster then the 3.07

Have you ever taken the car to the track with the gears?

Is tire spin a bigger issue with the blower and the lower gears than it was with the 3.07's?

 

[LETHAL GTS]

Tried them all at the track.All around I like the 3.33's.

I haven't done gears yet, but when I do 3.33's for me.

 

[Paul Hawker]

The deal with gears and a blower is the driving experience. With stock gears you get a slower, longer, tugging pull. As the boost steadily builds, the tires put the power down, and until the boost builds up, the tires are able to retain traction. Once boost is up, there is a point in the lower gears where traction will be lost.

With gears, it is more of an "Oh My God" feeling. The power snaps on, the boost hits harder and faster, and the car lunges ahead, on the verge of loosing traction, and often lots of wheel spin. It is a more violent, aggressive action, with driver fully engaged, and all synapses firing. The driver must use all his resources to keep the car under some sort of control.
Shifts come up rapidly, noises inside the car are screaming for attention. Tires...gears...traction...road conditions...cops...traffic...passenger screaming...tach...speedo...warping of vision...sensory overload...Then lift, and the world slowly returns to normal, and your Viper smoothly returns to its routine job of getting down the road.

The experience is very intense.

 

[Shelby3]

The deal with gears and a blower is the driving experience. With stock gears you get a slower, longer, tugging pull. As the boost steadily builds, the tires put the power down, and until the boost builds up, the tires are able to retain traction. Once boost is up, there is a point in the lower gears where traction will be lost.

With gears, it is more of an "Oh My God" feeling. The power snaps on, the boost hits harder and faster, and the car lunges ahead, on the verge of loosing traction, and often lots of wheel spin. It is a more violent, aggressive action, with driver fully engaged, and all synapses firing. The driver must use all his resources to keep the car under some sort of control.
Shifts come up rapidly, noises inside the car are screaming for attention. Tires...gears...traction...road conditions...cops...traffic...passenger screaming...tach...speedo...warping of vision...sensory overload...Then lift, and the world slowly returns to normal, and your Viper smoothly returns to its routine job of getting down the road.

The experience is very intense.

Paul, You must be talking about a centrifugal blower, not a twin screw. With the Roe, there are all the violent sensations you are describing with the stock gears. I like the stock gears much better with the Roe.

 

[Paul Hawker]

Good point.

Twin screw comes on faster and harder but not as strong at the top end. The Paxton comes on much softer and builds to a tire shreading creshendo!

Think stock gears may be better with twin screws.

Only drove one Roe supercharged Viper. Very pleasant experience. Liked the immediate throttle response.