Guess I'll use the VR-4

[Orion_134]

What do you think Speedy?
Dart 331, forged rotating assembly, internally balanced, out of box TW heads, custom cam, vic jr, 9.0-ish cr, pump gas, 3000 stall c4, 4.10's, and a 3200# car. Yes, carb'd 650:)
Questions:
What 8 rib blower/pulley combo will give max blower rpms at 65-7000 crank rpms? How can I visually check the VR-4 to make sure it is in good working order and set the preloads on it? I bought this off of Brians88lx, he's the guy who kept blowing head gaskets, and I trust that it is good, I just want to check.
Jesse

[speedytang]

To test the ball drive load put a torque wrench on the front pulley bolt and read your in/lb. I myself would use a 3.75" blower pulley and 6 3/4" crank pulley. This combination will give you estimated 8.5psi on a 331 ci engine with stock TW heads. Now I figured this on a stock FI profile cam. I don't have any Dyno numbers or boost psi numbers with a carb loaded into my Dyno Software. I have noticed on the Procharger setups that a 10psi kit for FI is only 8psi with a Carb with the same pulley sizes. I am not sure what causes the PSI difference on the carb.

[Orion_134]

You think that is a safe speed with the cast impeller and oil cooler kit?
Jesse

[speedytang]

Your at 48k at 6000 rpm and you could rev higher but I doubt if your car will be making any power after that, you probably would just be putting stress on the motor.

[1BA67]

Hi, Just to chime in, You may find the 650 dp not to be enough on that set up with the supercharger. I had my carb built by a shop that builds blow-thru carbs only and they recommended a 750 for my 302. If you go to Fordmuscle.com there's a real good series on building a blow-thru stroker motor, including the fuel system. When you go to the site search High on carbs.

[Orion_134]

Speedy, I could just change the cam out to make power up there? I know the intake will go up there.
Jesse

[speedytang]

What is your cam specs, do you have the cam card that you can give me everything or scan it and send it to me and I can Dyno your combination.

[Dirk Diggler]

[Orion_134]

.499/512@.050 219/225@.050 112 lsa
Need anything else?
Jesse

[speedytang]

If you can find a 4" pulley you could see what happens boost wise at 6800 rpm, I myself see 10psi at 6600 rpm even in this heat "94" with my 3.75" and I am at 54k+ rpm on the VR4 and have had no problems with the unit. Your Carb as stated above is to small if you go over 5350 rpm the Dyno says you need a 850cfm in a supercharger application to have enough fuel at 6800 rpm.

[Orion_134]

You have no probs with the unit, but you have a billet impeller...I have the cast one. Why 6800? As for the carb, does it take into account changing jets and drilling PCVR's to gain more fuel under WOT than at idle? What kind of numbers did you come up with? 4" blower pulley, which crank pulley?
Jesse

[speedytang]

I put in 6800rpm because you said 6500-7000rpm so I split it in the middle. Cast impeller will still hold up just like the Novi2000 at 60k rpm. Of matter fact I will give everyone a clue in who is reading this topic, The First Novi 2000s had the VR4 Billet impeller but because of cost was changed to the cast and that is why the VR4 unit is cast also...Cost. I didn't go into the Carb settings just pulled in a 650cfm. All my boost measurements are with a 6 3/4" crank pulley. The dyno software has you at 435 whp but shows you choking at 5300rpm. My guess will be you will be really lean when you hit the 5000rpm mark. Without a Supercharger it is showing you to be using a 625cfm carb and to use a 850cfm with a 1400cfm supercharger at 6800 rpm @ 10psi.

[1BA67]

Also, the Stealth intake isn't good for blow-thru. You'll need to use a single plane, such as a Vic Jr.

[Orion_134]

Vic Jr, as was stated in original post:)
Speedy, how is my 331 with bigger heads "making" lower numbers than your 302?
Also, with a Dart, I am going to a solid lifter cam for a steeper ramp and not having to purchase the $400 link-bar lifters. So, I won't be going with the FI profile, although it does favor boost so much;)
Jesse

[speedytang]

My cars have come close with the Electronic Dyno Software to my real Dyno numbers but I have every number needed to complete the total reference charts. I put what I had for your car and using default on other things. I can give you reasons but most don't like what is said...lol
1. First your automatic eats power up. Lots of Power
2. Carb to small which it shows when I put a larger carb in the graph.
3. Just being a Carb seems to lower the numbers, when I put your car with a EFI running a Edelbrock Performer 'R' you gain 23 hp from 4200-6500rpm.
4. The software to generate WHP numbers has a Standard Transmission only causing a 12% power drop and a Automatic with your stahl a 22% drop.
5. You will know your real numbers by either putting it on a Dyno or at least taking it to the track to reverse engineer your 1/4 runs into horsepower.
6. I have so many hours on a Dyno using a Tuning Device that I have a every horsepower that this car can give.