how much hp going from 3 to a 3.5" dp?

Reply Subscribe

Thread Tools

Search this Thread

Jan 29, 2007 | 05:27 PM

#21

parish8

Thread Starter

single digit dreamer

iTrader: (6)

Joined: Mar 2002

Posts: 9,757

Likes: 4

From: omaha ne

Quote:

Originally Posted by SSilverSSurfer

damn thats insane, i guess its safe to say factory lines are good to 1k hp, lol

i am running meth so that helps a little and twin intank staged pumps. like i said above there is a chance that my head lifting problems are just me running out of fuel.

Jan 29, 2007 | 05:30 PM

#22

parish8

Thread Starter

single digit dreamer

iTrader: (6)

Joined: Mar 2002

Posts: 9,757

Likes: 4

From: omaha ne

Quote:

Originally Posted by engineermike

Subscribing.

I'm interested also. I'm running 17 psi boost, pulling 146 mph at 3750 lb, and making 700 rwhp, all on a single 3" downpipe. I can fit a 3.5", but it will be very tight, difficult, and make the car harder to work on. If I can't pick up 50 hp, it's not worth it for me.

i have a lot of room. it would just be a little money and work for me. hell i could squeeze twin 4" dp's on there i bet. if i can get 30hp it would be worth it for me.

Jan 29, 2007 | 07:57 PM

#23

1CAMWNDR

TECH Veteran

iTrader: (21)

Joined: Nov 2001

Posts: 4,247

Likes: 2

I think 30 rwhp is doable with twin 3.5" downpipes. I sure as hell don't see where it will cost you power. Might get better spool times also (if the 3" is choking the compressor wheel a bit).

Jan 29, 2007 | 08:15 PM

#24

parish8

Thread Starter

single digit dreamer

iTrader: (6)

Joined: Mar 2002

Posts: 9,757

Likes: 4

From: omaha ne

Quote:

Originally Posted by 1CAMWNDR

I think 30 rwhp is doable with twin 3.5" downpipes. I sure as hell don't see where it will cost you power. Might get better spool times also (if the 3" is choking the compressor wheel a bit).

it will probably cost me $200-$300 in parts to get it done and the better part of a day to get it done. if it's only worth a few hp then i dont know that i want to do it.

i do plan on turning it up higher eventualy. if it's not worth it now it will likely make a diference then.

Jan 29, 2007 | 08:33 PM

#25

NA$TY-TA

TECH Senior Member

iTrader: (21)

Joined: Aug 2002

Posts: 10,331

Likes: 1

From: San Antonio, TX

Jim,
On the run's where you lifted the heads were you logging the passes?? did you have any Knock???
Id like to see what she does with better fuel and more pump myself....
With 600lbs off the truck alone the truck should be in the 9's........ even with turning the boost down from your low 10 sec passes from before.....
Keep us posted on what ya see.

Kyle

Jan 29, 2007 | 08:48 PM

#26

parish8

Thread Starter

single digit dreamer

iTrader: (6)

Joined: Mar 2002

Posts: 9,757

Likes: 4

From: omaha ne

i did see a little kr. up to about 18psi it is prety much knock free. then at 19psi i see a little at the top of 3rd and 20psi it kicks in a little sooner. not a ton of knock. 2-3deg but it is in a saw tooth pattern wich i belive is probably real knock. i was just shooting for 9's and living on the edge. i got beat into the 9's so now i am going to have to step up my goal.

my experience with 118 octane is that it is a lighter fuel so you need more of it and would make my fuel short comings worse so i couldn't try that. next year should be fun.