Torque on the 2008 and Intake Manifold

[vincy]

OK Guys, don't beat up on me, but I think the 2008 could use more torque at low RPM. I have had a couple 383 ci stroker Vets and never downshifted them and used 6th gear a lot and 5th for passing. With the 08 Viper I spend more time in 4th and 5th. The engine has less low speed torque than I expected.

In some ways it behaves like a turbocharged car. The power really comes on strong at the revs increase. So once the wheels spin they keep spinning.

Does anyone else feel this way about the low rpm torque?

Looking at the intake manifold I wonder why there are not runners for each cylinder like they have on the Vets. It seems this would increase torque. Has anyone tried making such an intake manifold for the Viper? Are there are long runners for each cylinder inside or on the bottom?

This is my first Viper. Don't flame me. I'm just giving my impressions and ansking questions. I would like to increase the low rpm torque. Since the car will be at road tracks I don't want to go the super/turbo charger route.

Thanks to all.

 

[Nader]

While I do know that the 08 has a bit less torque in the low end due to the variable cam design compared with the 8.3 liter, it is not significant. Considering you are running the largest CI prodction engine on the street there should be tons of torque. The torque in my 2004 still impresses me to this day. Where do you feel the torque is low?

OK Guys, don't beat up on me, but I think the 2008 could use more torque at low RPM. I have had a couple 383 ci stroker Vets and never downshifted them and used 6th gear a lot and 5th for passing. With the 08 Viper I spend more time in 4th and 5th. The engine has less low speed torque than I expected.

In some ways it behaves like a turbocharged car. The power really comes on strong at the revs increase. So once the wheels spin they keep spinning.

Does anyone else feel this way about the low rpm torque?

Looking at the intake manifold I wonder why there are not runners for each cylinder like they have on the Vets. It seems this would increase torque. Has anyone tried making such an intake manifold for the Viper? Are there are long runners for each cylinder inside or on the bottom?

This is my first Viper. Don't flame me. I'm just giving my impressions and ansking questions. I would like to increase the low rpm torque. Since the car will be at road tracks I don't want to go the super/turbo charger route.

Thanks to all.

 

[FE 065]

What axle ratio was in your 383 Vettes? Vipers run a 3.07.

 

[wallbanger]

people don't use 6th gear much especially tracking.... i use 6th when i'm >85mph cruising but having lived in maryland there are a lot more cops there than where i live now

probably need to look into gears or
http://forums.viperclub.org/rt-10-gts-discussions/610191-switch-3-55-gears.html

belanger headers ,cats,exhaust have been adding torque across the whole power band i believe..
http://forums.viperclub.org/srt10-s...-2008-viper-without-belanger-exhaust-kit.html

here is a quote from woodhouse on the system
it will really wake her up! you will see an immediate 55-60hp with more to come after a couple hundred more miles.

...rcl4668 just added his set and he tracks his car maybe he could chime in with his impressions.. mine are going on next week

otherwise there is a TT 08 1000hp on ebay

 

[RayC]

Are there are long runners for each cylinder inside or on the bottom?

.

yes runners are much longer than they appear. I don't have a picture but they are quite a work of art when you see them internally. I believe this is part of the reason for two piece design. Sounds like you are used to more gear.

 

[wallbanger]

Also vincy your feeling about the torque is a little strange ... this was your first post on initial impressions of the car and i quote

"Holy S*%^, the thing is a monster. It was delivered at night but we took it out for a spin. Leaving our street I turned onto the connecting street and the rear end kicked out, almost hit by the oncoming car. That would have been a record for us, dented in 30 seconds. I didn’t try to kick out the rear, I guess I didn’t know the torque and have gotten used to traction control. We continued and had no traction, every time I touched the gas the wheels spun and got a little sideways. Now I know you have to be on a straight path when you spin the wheels, again something I forgot after getting used to traction control. We should have realized it was 30 deg where the PS2s turn into stone, but we forgot"

 

[vincy]

Also vincy your feeling about the torque is a little strange ... this was your first post on initial impressions of the car and i quote

"Holy S*%^, the thing is a monster. It was delivered at night but we took it out for a spin. Leaving our street I turned onto the connecting street and the rear end kicked out, almost hit by the oncoming car. That would have been a record for us, dented in 30 seconds. I didn’t try to kick out the rear, I guess I didn’t know the torque and have gotten used to traction control. We continued and had no traction, every time I touched the gas the wheels spun and got a little sideways. Now I know you have to be on a straight path when you spin the wheels, again something I forgot after getting used to traction control. We should have realized it was 30 deg where the PS2s turn into stone, but we forgot"

I think we had cold tire syndrom that night and ran it at high rpm. We didn't do any continuous speed cruising, so it was all low speed then step on it type testing. Its the torque at highway cruise that I now think feels low. The engine comes on like crazy when the rpms get higher.

 

[adamlotus]

get the belanger exhaust system and go from there

 

[CitySnake]

Its the torque at highway cruise that I now think feels low.

Seems a bit odd. The only answer is the rear end ratio compared to whatever cars you are comparing it to. There's no other (production) car on the road with as much torque below the curve as your Viper. Are you looking to pass, or lay rubber at 70MPH in 6th gear? Even in 5th gear on the hiway, turning 1,500 RPM, you can pretty much pass anything on the road with half throttle.

 

[Kai SRT10]

As other posters have written, it's a gear issue. 6th gear is not useful for anything except for increasing gas mileage on the highway. From a performance standpoint, the Viper as it comes from the factory really has a 5 speed transmission. 6th gear is just too high. Almost no amount of torque would make it useful.

I have a race transmission with closer ratio 5th and 6th gears. It makes a big difference when accelerating hard in the upper gears.

 

[Nader]

That explains it. 6th is so low that it is nearly impossible to use at normal freeway speed especially if you have to manuever around someone. I use 5th 90% of the time and only 6th when over 70 with clear sailing.

I think we had cold tire syndrom that night and ran it at high rpm. We didn't do any continuous speed cruising, so it was all low speed then step on it type testing. Its the torque at highway cruise that I now think feels low. The engine comes on like crazy when the rpms get higher.

 

[fixumm]

yap...6th gear over 75 mph and for mpg only

 

[vincy]

What axle ratio was in your 383 Vettes? Vipers run a 3.07.

I think the Vets are 3.42, that is probably the reason.

 

[vincy]

As other posters have written, it's a gear issue. 6th gear is not useful for anything except for increasing gas mileage on the highway. From a performance standpoint, the Viper as it comes from the factory really has a 5 speed transmission. 6th gear is just too high. Almost no amount of torque would make it useful.

I have a race transmission with closer ratio 5th and 6th gears. It makes a big difference when accelerating hard in the upper gears.

Is 6th gear 1 to 1? Or an overdrive?
Is 5th gear 1 to 1? Thanks

 

[Nader]

4th is 1 to 1. 5th and 6th ar both overdrive gears.

Is 6th gear 1 to 1? Or an overdrive?
Is 5th gear 1 to 1? Thanks

 

[Paul Hawker]

4th gear = 1:1
5th gear = .75:1 overdrive
6th gear = .5:1 super overdrive

As others have stated. It is not a lack of torque, but the massive overdrive.

 

[Vipermann]

3.07s are terrible. 3.33 gears should be an option, and how ACRs come standard.

 

[Kai SRT10]

3.07s are terrible. 3.33 gears should be an option, and how ACRs come standard.

I don't mind the 3.07 gears from 1 through 4. Maybe not so good for drag racing, but I think they are very good for road racing. My only issue is with 5th and 6th.

 

[Peter Nielsen]

Isn't 6th gear needed to achieve top speed? I always thought that the relatively low redline RPM is the reason why 6th is geared the way it is... ?

Peter

 

[caseyse]

Isn't 6th gear needed to achieve top speed? I always thought that the relatively low redline RPM is the reason why 6th is geared the way it is... ?

c/d and hp will limit the top speed, and with the Viper's gearing, one would want to be in 5th gear to optimize the engine's RPM/hp.

 

[vincy]

Thanks for all your comments. We will be running the car at Summit Point and figure we will hit 150 mph on the long straight. Can someone direct me to the top speed in each gear with the 3.07 and a 3.33? I don't want to shift into 5th?

Thanks

 

[vincy]

3.07s are terrible. 3.33 gears should be an option, and how ACRs come standard.

I agree, I think the gearing is too high. What is involved in changing to a 3.33? Thanks

 

[Canyon707]

Well I have three diffs in my garage one 3.07 one 3.55 and one 3.73 I don't do long trips mostly just day drives. The 3.07 are hard to drive in traffic. The 3:55 are good all around gears and I do like them. The 3:73 are the most fun since the power to the wheels is incredible. Whats funny about this is my wife likes the 3:73 set she loves being pinned to the seat. Takes me 2.5 hours to change out the diffs.

 

[Nyoka]

OK Guys, don't beat up on me, but I think the 2008 could use more torque at low RPM. I have had a couple 383 ci stroker Vets and never downshifted them and used 6th gear a lot and 5th for passing. With the 08 Viper I spend more time in 4th and 5th. The engine has less low speed torque than I expected.

In some ways it behaves like a turbocharged car. The power really comes on strong at the revs increase. So once the wheels spin they keep spinning.

Does anyone else feel this way about the low rpm torque?

Looking at the intake manifold I wonder why there are not runners for each cylinder like they have on the Vets. It seems this would increase torque. Has anyone tried making such an intake manifold for the Viper? Are there are long runners for each cylinder inside or on the bottom?

This is my first Viper. Don't flame me. I'm just giving my impressions and ansking questions. I would like to increase the low rpm torque. Since the car will be at road tracks I don't want to go the super/turbo charger route.

Thanks to all.

This subject has been covered well since first posted but I thought I'd add these facts for perspective when comparing the new Viper to Vettes (or Chevy motors) of all persuasions: the ZO6 makes 470 lb.ft at 4,900 RPM, the '08 SRT V10 makes 470 lb.ft at approx. 2,500 RPM - a lack of low-end torque is not the issue. As many have pointed out, it's gearing, although I find mine hard to stick to the ground in first and second if driven aggressively; I have postponed plans to go to 3:33s.

As for the "turbo" comment: The variable timing cam-in-cam - a first in OHV engine history BTW - was engineered to ensure the new Viper passed all state emission control and NOISE standards under 'normal' driving conditions (adding nearly 100 HP presented problems). The new cam restricts intake/exhaust overlap up to 3,600 RPM (where the engine is making 500 lb.ft. but only 325 HP) smoothing out the idle and lowering the decibels in the process; then, it opens up to maximize torque (560 lb.ft. only 1,500 RPM later @5,100 RPM) but is really letting the HP loose, delivering an additional 225 HP over the same period (550 HP at 5,100 - peak HP is at 6,000RPM): the driving experience is definitely not comparable to a small block screamer - regardless of gearing - and may compare to a turbo rush, although I've never experienced a big block turbo. Personally, I find the cam profile and combo of monster torque and HP with NASCAR gearing way more exhilarating than a typical quarter mile 'red-line-at-the-lights' configuration.

My experience is that 6th gear is great for flat terrain over 70 MPH. I took my '08 through the Appalachians twice (a trip I highly recommend) and stayed in 5th averaging 75/80 MPH - seemed responsive enough for the little passing that was involved and, unlike 4th at that speed, made normal conversation possible. 6th at 1,500 RPM climbing hills is just annoying.

The car makes its top end in 5th. 6th is for those moments when you want to conserve gas at 202 MPH because in 5th you'll empty the tank in 20 minutes. Those SRT guys think of everything...

 

[Nyoka]

Thanks for all your comments. We will be running the car at Summit Point and figure we will hit 150 mph on the long straight. Can someone direct me to the top speed in each gear with the 3.07 and a 3.33? I don't want to shift into 5th?

Thanks

'08 SRT 10 Coupe Speeds, by gear/RPM:
1st: 62 MPH @6,250
2nd: 91 @6,250
3rd: 127 @6,250
4th: 164 @6,250
5th: 202 @5,450
6th: N/A Top speed reached in 5th.