How much boost should I shoot for out of my Vortech. I am trying to finish off the upgrades to my current set up. I installed a Vortech and got a little greedy along the way, now I gota have more. I'm installing an intercooler now but also will be changing pulleys to get more boost once I'm done with the intercooler. Just how much is the question???
Here's the scenario....
Stock Vortech no intercooler stock 3.33 pulley got me 7lbs of boost. I threw on a 2.95 pulley just for a run or two so I could get a feel for how much it increased my boost. It went up to 9lbs, again with no intercooler. Two pulley sizes got me 2lbs so 1lb increase for each pulley size decrease. I do have long tubes and custom 3" single exhaust so I think the little lower boost numbers are due to the free flow. Actual boost would probably be higher.
Once I add the intercooler, how small of a pulley do I go with.
Here are my pulley calculations:
3.33"-2.95"=0.38" got me 2lbs so .38/2lbs=.19 inch decrease yeilds 1lb.
I'm at 7lbs stock with no intercooler. I would like to be around 12 before installing the cooler to maybe get me to around 10 after the intercooler.
I can go with a Reichard 2.5 pulley. 3.33"-2.5"=0.83"decrease
.83"/.19" to get 1lb =4.4lb increase. 4.4 added to my stock 7 = 11.4 before adding an intercooler, which should be about 9-10 after the intercooler.
My question, is that too much? I think my boost numbers are low because it's flowing more. Am I asking for too much? I know my boost numbers would be higher on a stock truck. It will be tuned properly, so tune is not an issue. It doesn't get abused that often, so it wouldn't be constantly pounded on. Only the occassional WOT run. With the intercooler and safe tune, should I go for a 2.75" pulley or the Reichard 2.5"? The rest of my mods are listed below
Last edited by derrick929; 09-16-2008 at 02:35 PM.
Stay at or under 12lbs intercooled with a dead on tune and you should be fine.
Lowfast,
What I'm trying to figure out is whats 12lbs? My numbers seem low compared to more stock numbers? Do I take that into account? Or is my 12lbs more like a true 14 if I had more "backpressure" so to speak.
with better flow ie long tubes and decent exhaust, cams, ported and polished heads etc will make more power on less "boost" since boost is only restriction and power is made by actual airflow thru the engine.
you're making decent boost for your mods and I believe you are pushing your luck without an innercooler.
I would seriously consider the 2.5" pulley and I would dyno it with the innercooler and current pulley and then check the power numbers to see how close you are to the threshold of a factory non-svt block
__________________ thanks to Dirty88 for the sig
- '01 Procharged Lariat on a custom suspension - Tuned by Troyer
- '03 Harley Davidson Edition - still stock and staying that way
- New Eddie Bauer Expedition - Tuned by VMP
Yeah, I am afraid I might be crossing that fine line..... I want to be right at it without pushing it too far. Just gets expensive at $150 per pulley(reichard racing) and $185 per tune. Trying to limit my guesses as much as I can.
__________________
2002 5.4 Supercrew
Vortech Supercharger
Dynatech Headers
Magnaflow High Flow cats
42lb Injectors
2600 SCT Big Air Meter
Factory Tech Separator Plate
Flex-a-Lite E-fans
Walbro 255lph Pump
Accel COP's
MotoBlue Connectors and Boots
NGK Plugs
Superduty Tranny Cooler
JLP Shackles
innercooler, dyno and then see where you are at before you add anymore unless you want to risk the engine; but then again if you blow it up you always build it bigger and better
my truck now makes around11psi and I have a better crank pulley just waiting but i know better than to stick it on, I'd rather pull a tired engine than a ruined engine.
[quote=tarajerame;3377367]but then again if you blow it up you always build it bigger and better QUOTE]
Good reason.... I will probably go for it, worst case is about $2,500 and a brand new short block...then I can put as much boost to it as I want and not worry.
__________________
2002 5.4 Supercrew
Vortech Supercharger
Dynatech Headers
Magnaflow High Flow cats
42lb Injectors
2600 SCT Big Air Meter
Factory Tech Separator Plate
Flex-a-Lite E-fans
Walbro 255lph Pump
Accel COP's
MotoBlue Connectors and Boots
NGK Plugs
Superduty Tranny Cooler
JLP Shackles
I'm pretty sure I'll have to pull some timing out.... it was knocking a little with the 2.95" Only made a run or two just to check.
It will only get worse with the intercooler. I'm not positive, but I think that the pcm starts pulling timing at 150* iat. So, considering the ambient temps for your neighborhood in a couple of weeks? when you have the cooler working, there will be no timing pulled at all. My thinking is that your iats will be 125* or less.
My last datalogs with the same cooler at 10-11 psi, 105* ambient showed 134* iats.
Another way to look at it, how much power are you currently putting to the wheels? In supercharged form (on stock non-L internals) around 400rwhp seems to be the upper safe limit, after that point you are walking a very fine line IMHO. The more power you can get on less boost all the better. You are dyno tuning this with a wideband, correct?
__________________
2003 DHG Supercrew
20's, Dropped, Procharged and Liv'n Large!
Another way to look at it, how much power are you currently putting to the wheels? In supercharged form (on stock non-L internals) around 400rwhp seems to be the upper safe limit, after that point you are walking a very fine line IMHO. The more power you can get on less boost all the better. You are dyno tuning this with a wideband, correct?
Yep, it will be tuned with a wideband. No dyno though....Current tune is done by JJ at Woodbine Motorsports.
thanks to Dirty88 for the sig
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