Acceleration in 6th...

[S8ER01Z]

I've been searching for a couple of hours now.. probably using the wrong terms but had a question.

In the F-body our weak LS1 won't push 6th gear... so you can top the car in 5th gear and when you shift to 6th you actually lose speed. The LS1tech guys say it takes a decent amount of power to actually push 6th gear on our setups and I was wondering if this was the case for the Cobra as well. A guy I know just picked up an 03 Cobra with pulley, tune ,exhaust (claimed it makes 450rwhp)... and they were talking about top speed runs in 6th gear. From everything I know I would think 6th would result in a slower speed than 5th. (again coming from LS1 F-body T56 3.42 setups)

Any insight on this? Thanks!
:beer:

 

[98 Saleen Cobra]

yes tell your buddy to join this site and search top speed pulls.. basically it results in the motor melt down

 

[.n0b.]

You can but I wouldn't recommend it for the head's sake.

 

[03cobra#694]

Speed is limited to 155+/- electroniclly in 5th&6th,unless it has been disabled.

 

[MoKo_03SVT]

terminators still pull/gain speed in 6th gear. they dont lose speed.

not saying you want to go get in your buddys cobra and see if you can peg the speedo in 6th gear. because even though you could....you might end up buying your friend a new engine.

 

[S8ER01Z]

Thanks guys.. I already told him what I knew about tuning issues/ the piston clearence / heat, etc (basically the top speed = boom theory)... There must be something drastically different that I overlooked on the Cobra... I don't think 450rwhp is enough for me to push 6th at all. (will look into the gearing differences)

The limiter on his is gone (according to the guy who owned it)... when they added the pulley / tune it was removed.

 

[WhiTriCobra]

+1, it will still (barely) pull in 6th but i wouldn't even take a chance of doing that in 5th, let alone 6th gear.

 

[Evil Bender]

6th gear felt much improved with 3.90s installed

 

[F8l Vnm]

i had 2 blown motors , part of it I think was the High speed rolls I used too..

 

[HEMIHUNTER]

Just curious, you have over 2,000 posts and you're a chevy guy?
Good question on the gearing. some guys go with a viper gearset i think its a bit lower and might get you some more revs. If you have a z06 i would think the same would apply. Thats how vettes beat the gas guzzler tax[ gearing in 6th].
IMHO the inabilty [ or almost inability ] to do sustained high speed runs is the Cobras ONLY weak link. But thats part of the design anyway. A mustang over 160 sustained can be interesting.

 

[i8urSS]

i dont do any high speed runs in 6th but if i'm on the highway alot of times i dont gear down to pass people. it pulls pretty hard in 6th even if i stay out of the boost. its weird to think the ls1 wont.

 

[Nadra]

6th gear felt much improved with 3.90s installed

Of course it did; you changed the gear reduction. 4th gear is 1:1. 5th and 6th gears are over driven. Just plain stoopid to roll WOT in those 2 gears. You are making the car work unnecessarily hard.

 

[S8ER01Z]

i dont do any high speed runs in 6th but if i'm on the highway alot of times i dont gear down to pass people. it pulls pretty hard in 6th even if i stay out of the boost. its weird to think the ls1 wont.

Well the car will accelerate in 6th.. but when you are pushing 160+mph the air resistance becomes incredible and I guess we just don't make enough power (in stock form you can only get to about 145mph in 6th, but in 5th it will pull right up to the 162mph limiter). According to some people on LS1tech it takes 500hp to over come 6th. Even the LS7 Z06 tops in 5th and loses steam in 6th.... that gearing is a PITA.

Looks like the better gearing and all that power make this a non issue on the Cobra. Good info. :beer:

6th - Rear
.50 - 3.42s (Camaro)
.63 - 3.55s (Cobra)

 

[S8ER01Z]

Just curious, you have over 2,000 posts and you're a chevy guy?

What can I say this is a great group of people. :beer:

I actually spend a lot of time helping my buddies out with their stangs (mainly foxbodies) and on occasion I can sucker one of them into helping me out with the Camaro. The back and forth can be fun but when it comes down to it we are all car guys and enjoy having some fun. Being the slowest in the group probably gets me more hassle than having the bow tie does. :rolling:

 

[hinds04]

side note 450+ terminators are a dime-a-dozen with pulley, tune, exhaust... mine made 452rwhp/469ftlbs

 

[S8ER01Z]

side note 450+ terminators are a dime-a-dozen with pulley, tune, exhaust... mine made 452rwhp/469ftlbs

Only thing that has me 'wondering' on that end is I rode in the car and it's definately faster than mine (hell it was faster stock so that's a no brainer) but it doesn't feel 10mph faster (if that makes sense)... He was really 'iffy' when he listed the mods... left out some stuff until I asked (like exhaust mods).. he just got it so I guess I have no real idea at this point. Waiting to see how it runs at the track.

Nice numbers btw!

 

[Black Talon]

side note 450+ terminators are a dime-a-dozen with pulley, tune, exhaust... Mine made 452rwhp/469ftlbs

+1

 

[Jroc]

GM typically runs taller overdrives than Ford.(probably one of the reasons they get such good MPG)

In a Terminator you can accellerate from say 45 to 60 without downshifting out of 6th, or you can pass fairly swiftly from 60 on up without downshifting out of 6th also.(and I'm talking less than 1/2 throttle. I didn't go around trying to boost the hell out of 5th/6th gear) Trying to do that in a Fbody is a slow affair, but at the same time their motors turn less rpm's at any given speed driving down the highway. Its kind of a trade off. I would rather Ford use a little taller final overdrive than they do.

 

[S8ER01Z]

GM typically runs taller overdrives than Ford.(probably one of the reasons they get such good MPG)

In a Terminator you can accellerate from say 45 to 60 without downshifting out of 6th, or you can pass fairly swiftly from 60 on up without downshifting out of 6th also.(and I'm talking less than 1/2 throttle. I didn't go around trying to boost the hell out of 5th/6th gear) Trying to do that in a Fbody is a slow affair, but at the same time their motors turn less rpm's at any given speed driving down the highway. Its kind of a trade off. I would rather Ford use a little taller final overdrive than they do.

Yeah given the top speed limitation in stock form one would think they would have made 6th purely for gas mileage. I know I can't complain about the mileage I knock out in the old ls1 even if it is slow. :coolman:

 

[HEMIHUNTER]

What can I say this is a great group of people. :beer:

I actually spend a lot of time helping my buddies out with their stangs (mainly foxbodies) and on occasion I can sucker one of them into helping me out with the Camaro. The back and forth can be fun but when it comes down to it we are all car guys and enjoy having some fun. Being the slowest in the group probably gets me more hassle than having the bow tie does. :rolling:

+1 Thats what its all about:thumbsup: