Hi,
Its been awhile since the site has been up and I am glad to see it is up again. =) . I was going to sell my VR-4 last year and install a V-3 Vortech, but decided to stick with the Paxton until at least someone makes me an offer I can't refuse to sell it =)
Anyway, I wanted to share a little bit of Tech #'s from my setup so some folks out there who have questions about the performance capabilities of the VR4 and what it is capable of. Now, keep in mind, this is what I have going on with my setup and it depends on your car and Tune, Etc, Yours will be different. But If my post can offer any insight, or even get any responses as to ways to improve my setup or help others improve theirs, then it helps =)
This Car is a 1993 LX 5.0 and so you know what changes i made over stock are:>> - Stock Bottom End with Forged Pistons and ARP Main, Rod Fasteners, MLS Headgaskets with 12pt ARP Head Bolts, GT40P Heads NOT PORTED, FRPP "E" Cam, 1.6 RRockers, Upgraded FRPP Springs and Retainers, GT40 Tubular Intake & 1/2" Spacer for Clearance issues I had over Valve covers, 70mm BBK TB, 38lb Injectors ( Fed by Walboro Hi-Flo255LPH & Stock Rail ), AFM Powerpipe with 90mm MAF, A/C Eliminated, Aeromotive Fuel Press Reg adjustable <- Important, GT40P FRPP Headers 1 5/8 and Bassani X-Pipe w/2 High Flow Cats, SCT Eliminator Custom Tune Done @ Performance Evolution in Smyrna DE on a SCT DynoJet.
My Power Adder setup - Paxton VR4 - Fully Rebuilt by Craig at Paradise Wheels a few years ago, Bosch Style Bypass, I also Installed the oil cooler setup, BUT, two things I added that were not included, I added a Trans Cooler that is for 35,000 GVW so its Bigger vs the Smaller one that comes with Craigs Kit, plus I installed an Inline HighFlow Trans Filter that has a Magnetic Element to catch any particles before going thru the Pump,
I Ran Two Headunit Pulleys, the first, I had to change out due to To Flywheel HP being to close to 500HP, which my Bottom End would not take in its current state forever, The second is based off the Stock 4.25" headunit Pulley, But I had Craig make me a Custom 8 Rib 4.25" Headunit Pulley to stop the Uncontrolled Belt slip from using a 6 Rib.
Anyway, Here are the Numbers from my Dyno Pulls:
- With 3.75" Headunit Pulley and 7" Crank Pulley, Both 8 Rib, Made 11.2PSI Boost And 422RWHP/488Torque @4600RPM ( Take 422 Divided by .85 and you get 496 Flywheel HP which is the borderline of the 500HP the stock Bottom End is good for before something cuts loose and this is if its built right. The .85 in case anyone is wondering is to account for the 15% or so loss of power thru the Drivetrain.
- With the custom 4.25" Headunit Pulley and 7" Crank Pulley also Both 8 Rib, Made 9.0PSI Boost And 405RWHP/447Torque @4500RPM ( 405 Divided by .85 gave me roughly 476Flywheel HP which is a small buffer so I can build a better short block sometime next year to handle more power, But I spent a lot of $$$ getting a T56 Magnum setup to handle the torque going to the wheels, so the Bottom end is gonna have to wait.
IMAG0648.jpg
Not to shabby in my opinion and I have the Dyno Sheets to prove it =), Of course its Not ALL due to the VR4 Blower, My Engine Breaths very well and all the Bolt On Parts: Intake,Exhaust and Mild Cam Compliment Each other well. So your Boost Numbers won't be like mine without having a good Breathing engine. Also, My Boost #'s come from the Vaccum Tree and NOT the HeadUnit. You get a Close to REAL Boost # at the Tree VS the Headunit ;-) Also, With my Lower RPM Max power #'s, I would think when I do build a better bottom end, I could Run a 3.50" Head Unit Pulley for more boost and not over spin it, But I don't remember what the Internal Limit of a VR4 is, Maybe Speedytang can chime in on that, I know an SN89 is 38,000 if i am correct.
In closing, for those who are not sure what supercharger to use, or do not have a clue or are sure of an old Ball drive, heres my thoughts. Its more fun to drive my LX with the VR4 down the track, Run Low 11's and be asked whats under the hood and to see them surprised an old Ball Drive is under there, then Running my 89GT with the Procharger setup I have. The VR4 is just plain cool to use if you ever get the chance to run one, but remember HEAT kills it, so don't go cheap when it comes to Not wanting to use an oil cooler, You have to, or it might not last long.
Questions, Comments, Opinions??? =)
My Very Best,
Chad
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