Not using all the boost I have............ :(
10-25-2009, 11:05 AM
#11
2nd Gear Member
Thread Starter
Join Date: Jan 2008
Location: California
Posts: 217
What do you mean? How are stock heads a "problem"? If anything he would be seeing less boost with aftermarket cylinder heads. I'm sure procharger doesn't assume everyone has aftermarket heads when they claim some kind of baseline estimate in boost for whatever kit they make. In fact, I bet procharger, vortech, KB, etc. state the psi of their kit based on a stock car.
I have a supposed 10 psi pulley (3.33") on my car and I see 10 psi with a Vortech aftercooler.
If I had longtubes, aftermarket heads, aftermarket camshafts, and/or a conventional intercooler I absolutely wouldn't see 10 psi.
I shouldn't have said "lost" boost before I understand that it really isn't lost just easy to say in conversation.
I have a supposed 10 psi pulley (3.33") on my car and I see 10 psi with a Vortech aftercooler.
If I had longtubes, aftermarket heads, aftermarket camshafts, and/or a conventional intercooler I absolutely wouldn't see 10 psi.
I shouldn't have said "lost" boost before I understand that it really isn't lost just easy to say in conversation.
10-25-2009, 11:43 AM
#13
The Rogue Mod
Join Date: Feb 2006
Location: Maryland Sucka's!!
Posts: 21,918
What do you mean? How are stock heads a "problem"? If anything he would be seeing less boost with aftermarket cylinder heads. YOU'RE KIDDING ME RIGHT!!!I'm sure procharger doesn't assume everyone has aftermarket heads when they claim some kind of baseline estimate in boost for whatever kit they make. In fact, I bet procharger, vortech, KB, etc. state the psi of their kit based on a stock car.I'D BE WILLING TO TAKE THAT BET!!
I have a supposed 10 psi pulley (3.33") on my car and I see 10 psi with a Vortech aftercooler.
If I had longtubes, aftermarket heads, aftermarket camshafts, and/or a conventional intercooler I absolutely wouldn't see 10 psi. PLEASE EXPLAIN HOW YOU FIGURE THAT ONE
I shouldn't have said "lost" boost before I understand that it really isn't lost just easy to say in conversation.
I have a supposed 10 psi pulley (3.33") on my car and I see 10 psi with a Vortech aftercooler.
If I had longtubes, aftermarket heads, aftermarket camshafts, and/or a conventional intercooler I absolutely wouldn't see 10 psi. PLEASE EXPLAIN HOW YOU FIGURE THAT ONE
I shouldn't have said "lost" boost before I understand that it really isn't lost just easy to say in conversation.
In a nutshell, if an engine can't breath, it can't make boost. It's just that simple.
You have more patience than I.
10-25-2009, 12:00 PM
#14
6th Gear Member
Join Date: Feb 2006
Location: Virginia
Posts: 11,786
Boost, regardless of how it's made, can only "flow" as well as the induction system of an engine will allow it to. Meaning, as sxynerd has already given a great example, if anywhere in the intake system is restricted, for w/e reason, the flow will be reduced. Stock heads are a huge restriction for a boosted application. Aleviating that restriction means added flow, which inturn means added boost, not less.
In a nutshell, if an engine can't breath, it can't make boost. It's just that simple.
You have more patience than I.
In a nutshell, if an engine can't breath, it can't make boost. It's just that simple.
You have more patience than I.
Sticking with my analogy, Think of his phrase "system is restricted" and apply it to that Freeway. That 5 lane fwy has a period of construction for 1 mile and goes down to 2 lanes again. Although all the FWY is 5 lanes at that "Bottle necked 1 mile" (Stock heads) it still a place of restriction which takes the commute back up to 1 hour.
BUT, in your case with your low boost level, (Yes 10lbs is considered low) the heads aren't restricting that much. Your system is just running slightly more efficient with the LT's. If you add Ported head AND larger valves without increasing the blower air volume, your boost will go down again... But still moving that same 10,000 cars while still more decreasing the time to work.
Last edited by Sxynerd; 10-25-2009 at 12:02 PM.
10-25-2009, 02:26 PM
#15
4th Gear Member
Join Date: Mar 2008
Location: asdf
Posts: 1,600
Correctly,
"Aleviating that restriction means added flow, which inturn means [LESS] boost, not [MORE]."
Last edited by vanquish; 10-25-2009 at 04:38 PM.
10-25-2009, 05:56 PM
#16
2nd Gear Member
Thread Starter
Join Date: Jan 2008
Location: California
Posts: 217
Right now I'm making 350HP and 383TQ to the wheels. Is it safe for me to change the pulley to say a 12lb as long as I don't go over 400HP/TQ since I don't have forged internals?
10-25-2009, 06:05 PM
#17
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Join Date: Nov 2006
Location: MA
Posts: 2,402
10-26-2009, 08:14 AM
#19
4th Gear Member
Join Date: Aug 2007
Location: Shelbyville, Indiana
Posts: 1,088
Are you sure that you have a 10 lb pulley? What are your reference rpms for the 7-8 lbs of boost? 350 rwhp (manual transmission) is normal for the ProCharger stock pulley (8 lbs of boost). I'm running the same supercharger with an 8 lbs pulley through the same exhaust (BBK LTs & catted x-pipe). I do have a new crank pulley that might alter things a bit. I get 8.9 psi at 6000 rpms. I was expecting the pressure to be lower when I put on the LTs but it wasn't. I think I'm still getting restriction through the catted x-pipe.
Just a thought: You're not running an underdrive crank pulley are you? The previous owner put one on my car. That's why I had to get a new crank pulley when the supercharger was installed.
10-26-2009, 12:17 PM
#20
2nd Gear Member
Thread Starter
Join Date: Jan 2008
Location: California
Posts: 217
For a while I thought this was going on your pushrod 302. I had to search through your old posts to find out what kind of car you have. Please update your garage.
Are you sure that you have a 10 lb pulley? What are your reference rpms for the 7-8 lbs of boost? 350 rwhp (manual transmission) is normal for the ProCharger stock pulley (8 lbs of boost). I'm running the same supercharger with an 8 lbs pulley through the same exhaust (BBK LTs & catted x-pipe). I do have a new crank pulley that might alter things a bit. I get 8.9 psi at 6000 rpms. I was expecting the pressure to be lower when I put on the LTs but it wasn't. I think I'm still getting restriction through the catted x-pipe.
Just a thought: You're not running an underdrive crank pulley are you? The previous owner put one on my car. That's why I had to get a new crank pulley when the supercharger was installed.
Are you sure that you have a 10 lb pulley? What are your reference rpms for the 7-8 lbs of boost? 350 rwhp (manual transmission) is normal for the ProCharger stock pulley (8 lbs of boost). I'm running the same supercharger with an 8 lbs pulley through the same exhaust (BBK LTs & catted x-pipe). I do have a new crank pulley that might alter things a bit. I get 8.9 psi at 6000 rpms. I was expecting the pressure to be lower when I put on the LTs but it wasn't. I think I'm still getting restriction through the catted x-pipe.
Just a thought: You're not running an underdrive crank pulley are you? The previous owner put one on my car. That's why I had to get a new crank pulley when the supercharger was installed.
