How much boost will I make?

Reply Subscribe

Thread Tools

Search this Thread

May 15, 2004 | 11:29 AM

MstgKillr

Thread Starter

TECH Apprentice

iTrader: (4)

Joined: Dec 2001

Posts: 372

Likes: 0

From: Cape Coral, Florida

How much boost will I make?

I have the stock ATI crank pulley and 3.6 blower pulley with a D-1SC, I see 8#'s @ 6,000 rpms now. Soon I will have the SD Concepts 8 rib spring tensioner with a 7.250 crank pulley and a 4.0 blower pulley. How much boost will I make? How much boost will I make with some LT's?

I am just going to take a guess here, if stock I see 8#'s of boost at a impeller rpm of 39,975 I get 1# of boost for every 4,997 rpms. With the SD Concepts, if I use the same formula (44,586 / 4,997) I get 8.9#'s of boost @ 6,000 rpms. Does this look right to everyone. With a good set of LT's how much boost will I lose. I don't really want to go over 10#'s on a stock engine.

impeller rpm=(crank pulley dia / blower pulley dia) * 4.1 * engine rpm

Stock ATI setup = 8#'s @ 6,000 rpms
39,975=(5.85 / 3.6) * 4.1 * 6,000

SD Concepts setup = ?
44,586=(7.25 / 4.0) * 4.1 * 6,000

Thanks

May 15, 2004 | 11:38 AM

NA$TY-TA

TECH Senior Member

iTrader: (21)

Joined: Aug 2002

Posts: 10,331

Likes: 1

From: San Antonio, TX

Quote:

Originally Posted by MstgKillr

You forgot about belt slip with the stock 6 rib setup........ One person with the SD Concepts kit witht the stock 6 rib setup and a stock crank pulley and a 3.2" blower pulley was seeing 7 psi (so was i with the same pulley combo a long timago with LT's and a baby cam) He switched out to there setup and saw 10 psi...... spinning the same RPM's as before........... or now he was spinning the RPM's he was sapposed to be spinning all along. I can tell you on the 6 rib setup i ran before i was seeing 11-12 psi with a MMS 7.85" crank pulley and a 4" blower pulley....... thats spinning 49,886 blower rpm;s though....... only one way to find out......... You can always get a good set of 6.0L heads to drop compression and boost will drop but power will stay....
Kyle

May 15, 2004 | 11:41 AM

8 Second Club

iTrader: (34)

Joined: Nov 2001

Posts: 10,852

Likes: 1

From: Knoxville, TN

Its not that linear, its really hard to say unless you actually try it. I picked up 1 PSI going from a 3.4 to a 3.2, thats ~3000rpm. I would think in the blowers efficiancy range it would take less impeller speed change to make the same amount of boost then at higher/lower speeds. Depending on if you run cats and your catback a 1-1.5 PSI boost drop is fairly normal on a LT switch with no cats.

I dont think you will hit 10psi with that combo with a good set of headers/no cats - one way to find out though.