2.4 upper or 15% lower

[PARTSDUDE]

Question for you guys and gals. Back a few years ago, the common mod was an upper pulley swap. Now it seems on the 2013, the the lower is the most common. Why?? They are both going to spin the supercharger approx 18000 to 19000 rpm. I think any ways. Some worry about belt slip on the upper 2.4 pulley. How about any of the nightmares of the lower pulley taking out the crank shaft?? Which mod is safer? Which mod will produce more power? I am wanting approx 700 to 725 RWHP. Yes I know about suspension and traction. I was use to 706 RWHP with my 2010 Shelby. It hooked up well.
Just looking for any thoughts on the subject.
Thanks guys
Ted.

 

[Slowponycar]

http://www.svtperformance.com/forum...-2013-shelby-mods-make-you-go-mother-god.html

Birddoc had a great write up on how he got to over 700wrhp with just bolt ons. :beer: Its pretty amazing the power that he is putting down. I am going to do a different setup and hope to do it this spring/summer.:idea:

 

[kcobra]

Lower is the way to go I think. Makes more torque. Less belt slip, win win.

 

[Ninjak]

Lower is the way to go I think. Makes more torque. Less belt slip, win win.

Idler/Tensioner = no belt slip on upper
Upper is by far easier to do than the lower.

 

[Shhhh]

I went with Ford Racing 65mm twin TB, JLT 123mm CAI, 2.4 VMP pulley, division x idler and dyno tune and Im making 706/713 on 100. Stock exhaust as well.
Id say you'll be happy with an upper, I know I am and its way too much for stock tires and suspension anyhow.

 

[Lethalchem]

I'm curious about the OP's question as well. With the 03/04 Cobras the upper gave more hp and the lower more torque. I have no interest in the car making more torque, I like the idea of more hp though. Curious why it's not a more common mod.

 

[0mineralgrey3]

no slip with a tensioner??? I have a tensioner on the stock pulley and get a lil slip here and there. Going from 2.6 to 2.4....def gonna slip a lil more. Lower pulley makes more power and really not much slip increase.

 

[Shhhh]

no slip with a tensioner??? I have a tensioner on the stock pulley and get a lil slip here and there. Going from 2.6 to 2.4....def gonna slip a lil more. Lower pulley makes more power and really not much slip increase.

I never logged it stock but with the division X idler and a 2.4 I didnt get any slip while it was on the dyno this past weekend. Tires spinning on the dyno sure...but no belt slip. I believe it can happen and will so but I wouldnt say its a common occurrence.

 

[BOD89LX]

I did the 2.4 upper as well and added a metco idler and don't any slip that I can tell but I am sure there is some but not enough for me to worry about it, I plan to log a pass at the strip and see how much slip I get on a gear change as that is where it is most lilkey occur .

 

[PARTSDUDE]

Sounds like we have people on both sides of the fence.
The upper is easy to do myself in my garage. The lower is a bit much for me in my garage without a lift. On my 2010, I Installed a 2.9 whipple. Beautiful unit. Great power. Not enough whine. This time around, I want the whine. My 03 cobra screamed. I missed that sound.
That is my issue. Want the sound along with the power.

 

[BOD89LX]

Sounds like we have people on both sides of the fence.
The upper is easy to do myself in my garage. The lower is a bit much for me in my garage without a lift. On my 2010, I Installed a 2.9 whipple. Beautiful unit. Great power. Not enough whine. This time around, I want the whine. My 03 cobra screamed. I missed that sound.
That is my issue. Want the sound along with the power.

I can tell you that it will scream with a pulley and a CAI my blower is louder then my exhaust from inside the car.

 

[Shhhh]

Sounds like we have people on both sides of the fence.
The upper is easy to do myself in my garage. The lower is a bit much for me in my garage without a lift. On my 2010, I Installed a 2.9 whipple. Beautiful unit. Great power. Not enough whine. This time around, I want the whine. My 03 cobra screamed. I missed that sound.
That is my issue. Want the sound along with the power.

Not as loud as my '03 2.8KB Cobra but with a pulley and intake it is a lot louder thats for sure.

 

[0mineralgrey3]

HOw much boost are you guys seeing now with the upper?

I'm guessing the boost gauge stops at 20.0 psi cause i'm pegging it.

 

[Superhawk2002]

Going with the upper just because it's easier.


EDIT: And much cheaper for damn near the same increase in boost/power/torque.

 

[Ninjak]

Well I have a stock gauge still and its peg. I have full exhaust so I guess I am losing a few PSI on the boost, but I would guess I am somewhere at 17~18 with the 2.4.

The Dyno session was canceled today, due to the dyno being broken. Hopefully it will be back up tomorrow or Saturday so I can finally see what I am putting down.

Also I agree with Lethal. The upper I thought was for boost/power and the lower was for the TQ number. I can spin 315's 20's now from 40~50 rolls....so lord knows I do not need any more TQ

 

[topless10th]

Going with the upper just because it's easier.


EDIT: And much cheaper for damn near the same increase in boost/power/torque.

how is it cheaper, considering you need an idler, tensioner, and removal tool?

 

[0mineralgrey3]

^^ agreed.

I have two brand new IW 15% OD pulleys in the box for $550.

 

[Ninjak]

how is it cheaper, considering you need an idler, tensioner, and removal tool?

Depends on the size of the upper for the Idler/Tensioner. Puller is needed sure. So lets 300 bucks. (By the BY thats for a 2.4 200$ also have seen them for 150 $ and the puller 100$)

Lower. 550$ on the forums. More in store. Need a lift and tools to get it off. So shop time. So lets say you have a bud with a shop. You still payed 550 $

550>300 in my book.

 

[0mineralgrey3]

What about idler/tensioner?

 

[topless10th]

upper without idler and tensioner = slip. BTW ninja, they're in your sig.