Lower Pulley help

[laidback01]

I need input on what lower pulley to go with. I have a MMR 4.75 stroke bottom end with a Stiegemeir stage 7 ported Eaton with a 2.76 upper. Tuner said I'm not making any boost and I need a lower pulley. Any and all suggestions are appreciated.

 

[cj428mach]

Sounds like you need a bigger blower

 

[01yellercobra]

Does he mean low boost or no boost at all? I would think if everything is working you'd still see a couple pounds.

 

[laidback01]

Does he mean low boost or no boost at all? I would think if everything is working you'd still see a couple pounds.

Low boost

 

[laidback01]

Sounds like you need a bigger blower

Not ready to come out of pocket for that just yet.

 

[cj428mach]

A ported eaton has boost drop off on a stock motor, a built motor will be worse

 

[laidback01]

A ported eaton has boost drop off on a stock motor, a built motor will be worse

So what lower pulley to go with again?

 

[01yellercobra]

Friend of mine runs a Metco 4lb lower with a 2.76 upper on his stock engine.

 

[laidback01]

Friend of mine runs a Metco 4lb lower with a 2.76 upper on his stock engine.

Went with a 6lb lower.

 

[01yellercobra]

Went with a 6lb lower.

I'll be curious about the boost drop off. I'd be surprised if it pulled much past 5500rpm.

 

[laidback01]

I'll be curious about the boost drop off. I'd be surprised if it pulled much past 5500rpm.

Should I have went with the 4lb?

 

[01yellercobra]

Should I have went with the 4lb?

I would have, but I tend to error on the side of caution. From my experience the eaton doesn't like to be spun really hard. Even with the port jobs. That's why you see the high torque numbers when people spin the eaton hard. It's being spun beyond its efficiency range.

But I could be totally wrong and your set up will be awesome.

 

[BLOWN9646]

I'd swap that upper to a 2.93 with 6lb lower

 

[99 KOBRA]

I've got a built '04 (ported Eaton, 2.9 upper pulley and auxiliary idler, Manley pistons-overbore, 9.01 cr, etc.) with a Lethal return fuel system that did 485 rwhp, 447 tq on a Dynojet. The stock fuel pressure sensor was retained.