2,4,6,8# lower pulley?

[darknight01]

im new to the cobra and dont know a whole lot.i put a 2.76 s/c pulley on it and seen everyone is puttina lower pulley on as well.my first question is, is it the crankshaft pulley?and if not what pulley and what # do you use with the 2.76? thanks alot

 

[Posi]

Without a ported blower just stay with the 2.76 upper only. Adding a lower worth putting on the car would be a 4lb'er and that's way to much. It'll heat up and the car will pull timing more than likely.

 

[moddedmystic]

Yes its the crank pulley. I'd say go with a #2 or #4 with the 2.76 upper. I dont think you need a port, just a good tune.

 

[Posi]

If he goes with a 4lb lower with that 2.76 upper his hp peak in the rpm's is going to be around 5,300 or even lower than that. After that the hp will fall off very quickly and it won't carry it out.

So if someone wants to build a lot of heat and shift at about 5,400-5,600 rpm's then put a 4lb lower on it. If it's put on a dyno then what I said will be seen.

 

[BBCOBRA]

I can testify to that.
I have a 2.76 upper and when on the dyno for the typical 3 pulls it would give very close numbers with in 1-2 hp from the first pull to the third pull

After adding the 2# lower (I have no port yet) I saw a drop of about 3 to 5 hp from the first pull to the third pull. So, the 2# puts it right at that edge.

When I get it ported I plan to go with the 4# lower.

 

[lgonz051]

what posi said

 

[moddedmystic]

I guess it depends on the OP's goals for the car and plans for future mods. Either way you'll love all the extra torque you'll get with a lower.
After modding my car since early 2004 with everything I've learned, I'd save my money and get a 2.3 whipple. Lots of power and great resale for the car. Just my .02
:beer:

 

[pb1302]

Get a WHIPPLE.... you will run out of fun juice in that Eaton...

 

[cobrasvt57]

so how would your dyno chart look if you were shooting for 16Lbs with a 8lb lower or maybe a 10.Which upper would i need to run and how could i keep if from falling like that seeing that i'm going to be using 96-98 cobra cams which i hope will extend my power profile.
Thanks
Joel

 

[02b4ccamaro]

why would you ran a 10lb lower cobrabob has a web sight with all the pulley combos you can think of. 2.7 upper and a 4 pound lower is as big is you what to go thats around 16psi and 16psi is about the limit even on a ported eaton

 

[Evil Bender]

FYI the 8# and 10# lowers wont fit without rerouting and bending hoses and hard lines.

 

[03cobra5485]

would a 4lb lower be necessary if he ends up getting a ported blower, running the 2.76 pulley?

 

[Posi]

so how would your dyno chart look if you were shooting for 16Lbs with a 8lb lower or maybe a 10.Which upper would i need to run and how could i keep if from falling like that seeing that i'm going to be using 96-98 cobra cams which i hope will extend my power profile.
Thanks
Joel

Still peak early because it's the blower that'll hold you back. IMHO.

why would you ran a 10lb lower cobrabob has a web sight with all the pulley combos you can think of. 2.7 upper and a 4 pound lower is as big is you what to go thats around 16psi and 16psi is about the limit even on a ported eaton

You can run more but you just gotta have the right setup. Or don't street race with no cool down.

FYI the 8# and 10# lowers wont fit without rerouting and bending hoses and hard lines.

My 8lb lower fit my car with no issues. Maybe I got lucky.

would a 4lb lower be necessary if he ends up getting a ported blower, running the 2.76 pulley?

No not necessary but it would wake the car up some more with some nice useful torque down low and some more hp.

 

[02b4ccamaro]

so what would you say is the max reliable psi you would ran on your race ported blower

 

[Posi]

I'm running a 2.9/6lb combo now that's making 17+lbs and more than likely in some good cool weather be at 18+ pretty easily. You just have to have it all working together. Ported Dragon tb/plenum, Race Ported blower, ported lower intake, LT headers, o/r x-pipe, and good exhaust. Every little thing helps when you push things.

For most an upper only or even a mild upper/lower combo should be enough. Numbers are great but people get hung up on them. Dyno numbers are one thing but if you make to much heat on the street to use the power because things are to hot then it's better to just pulley for less and make the same numbers on the dyno or the street.

 

[cobrasvt57]

this is a swapped eaton build so hard lines you speak of i'm not going to run into and as far as heat the eaton is ported and i'm going to be using a newly designed heat exchanger/intercooler that should keep temps in control like none other ....... sorry but i'm still learning the pulley setups

 

[Tractionless1]

FYI the 8# and 10# lowers wont fit without rerouting and bending hoses and hard lines.

8# fits fine here.

I can testify to that.
I have a 2.76 upper and when on the dyno for the typical 3 pulls it would give very close numbers with in 1-2 hp from the first pull to the third pull

After adding the 2# lower (I have no port yet) I saw a drop of about 3 to 5 hp from the first pull to the third pull. So, the 2# puts it right at that edge.

When I get it ported I plan to go with the 4# lower.

I'd be willing to trade 3-5 top end HP for the lower/middle rpm TQ gain and less chance of belt slip a 4# will provide. My .02.

 

[Posi]

this is a swapped eaton build so hard lines you speak of i'm not going to run into and as far as heat the eaton is ported and i'm going to be using a newly designed heat exchanger/intercooler that should keep temps in control like none other ....... sorry but i'm still learning the pulley setups

4lb lower would be tops with that upper. Interesting comment on the h/e and the IC because there's none better so far than the stock IC. H/e sure but not the IC. There are some out there but they haven't been proven to be better. Either way good luck with your car.

 

[Fenixfire]

Decided to dig this old thread up to ask a related question. What can I expect if I run a 4 lb lower pulley with a 3.1 upper pulley?

I have to change the crank seal cuz its leaking oil and I decided I might as well upgrade to a 4 lb lower since the crank pulley is gonna be off it. Ill need a new belt right?

Keep in mind, im at high altitude and I only see 8 lbs of boost from the eaton right now with longtubes and a 3.1 upper. So if I add a 4 lb lower will that be enough to put me in the teens for boost at my altitude?

And yes I know I will need to retune it.

 

[Tifosi2003GT]

sounds like a killer chiller is needed. I'm running 2.93 4# with a killer chiller. I love this combo. I get no belt slip, but this winter is going out for port. Not sure yet which company I'm going to use tho.