With all the hype goin on with these blower setups, what is a typical setup that most people are going to in order to take say a 4.80/90 combination to 4.50/60s? Is it just a simple 671 blower setup from say the blowershop, run 2-4 psi of boost and thats it? Is it any more consistent or is it just a cheaper way to go faster than building a $20K+ motor? Just curious why so many people making the switch.

Its not really cheap any way you do it. For starters no matter what power adder you chose you will need a converter matched to it to manage the power you are going to make and a fuel system capable of matching the blower/Horsepower output. Most guys i've seen run an 8.71 street blower on their first go around because they are usually available relatively cheap. You could likely get a street 8.71, pulleys, intake and idler for 2500 or so dollars if you shop around possibly cheaper. These on your typical 12:1 to 13:1 500 to 540" motors can run 4.50s pretty easily if injected. Starting to see more carburetors they run well too but i don't have any experience with them.

When i made the swap i found a really cheap 14:71 and was already injected on methanol so i just installed the blower on top of my 555 12:1 compression, dart pro 2 380's, 780 lift cam, on methanol, and went racing. It made waaaay more power than i wanted. At 0% OD i ran high 4.30's/ low 4.40's in a 237" miller 4 link without even trying at 12 to 14 psi of boost. That was with a single 5" toilet. At 4% OD i was running 4.30 at 164, making 16-18 psi of boost. It was way too fast for my setup and consumed alcohol like i had a hole in the tank, so i sold the entire blower setup and went back naturally aspirated just more cubic inches and better cylinder heads. As it turns out my "el cheapo" 14:71 was a High helix, billet rotor, mag case littlefield and was actually a really nice blower just an old one, i guess that's why it ran so hard.

My buddies setup was a street cast rotor 8.71 on top of a 509, 12:1 compression, same 780 lift cam, brodix 2X heads, ran 4.40's at 162 ish in a 252 miller 4 link. He had to turn it up a good bit to make it run and eventually burned an intake valve, so he swapped to a big 14:71 high helix and runs well off into the 4.20's now when he wants to with no issues. His car seemed reliable and consistent at the 4.50 range with the street 8:71 before he started trying to make it go fast.

Just cause the blower is cheap doesn't mean its cheap to complete the entire setup. It's pretty costly if your setup isn't already configured for it. I thought mine was but the conversion ended up costing north of 5k by the time i was done. Intake alone was 1100 or so dollars.

The hot ticket seems to be the prochargers. Lots of them in top dragster right now. Not at all cheap though.
Some crazy arses are using turbos. That's a lot easier if you already run EFI.

So could you take like a 572 (4.500 bore x 4.500 stroke), that has relatively high compression at 15-1 comp, slap on a street 8.71 blower and turn it down to like 2 psi of boost without hurting anything? Or would that much compression cause bad things to happen? I’ve heard of people who take like a 555 that goes 4.90’s, slap on a blower and all of the sudden go 4.60’s with 2 psi of boost, no other changes other than take intake off and slap on blower and even put carb on top and say it’s fine.

Here are my thoughts for what it is worth and why I have not gone to a blower yet.

The blower takes maybe 35% of the horsepower and fuel to turn it. So your crank, rods and pistons are seeing way more power than goes to converter. So if the motor is making 2100 Hp after the blower it is putting around 1400 to the converter.

That extra horsepower shortens the life of the rotating assembly. Plus the blower may be hard on valve springs and valves.

So if you are able to run the number naturally aspirated then that is the way to go in my opinion. But if you need more power the blower will certainly do it.

One other issue is with a blower it is almost like ON or OFF and that makes it hard to get off the line with out spin or wheelies. From what I have been told the prochargers may be a little softer on the hit and pull more on top. Do not know how much difference if any just what I was told.

After wanting one my whole life and running a blower for the past year, I don't think I will ever NOT run a blower. Their just bad ass

I’m following this.

I’ll let the experts weigh in with the details, but I will say that instead of spending a bunch of money on heads, intakes, etc.. A blower pushes the charge in there..

Wanna speed up? Pulley and Pill change
Wanna slow down? Pulley and Pill change

I will add that a “no frills” BBC (standard short block, dart 360’s, flat tops, .720” cam) and a regular helix 8/71 is a pretty dang easy 4.70’s at 2200 lbs..

I had a plain Jane 582 in a 225 hardtail. Went 4.83 on motor (one pass ever), 6.91 on 1 kit and 6.62@204 on two kits. Around 13:1, 850 lift cam, nothing special.

I literally pulled the intake, changed the timing cover for a fuel pump drive, and bolted on a blower. Left the nitrous converter in.

1st pass underdriven was a 4.50. Went 4.teens with it the next year at about 14 over after bolting on zoomies

Many years, tears, and broken parts later I eventually went 3.99 in a different car.

A bunch of people around here are running street blowers with a single carb. From what I have been told they dont change anything else except lengthen the fuel line and strap the blower on and pick up 3 tenths. Same carb, same converter. I am pretty interested in this. from 3 to 6 psi of boost.

See here I change from blowers all my life and try to behave and run a simple injected deal.Boom Everybody goes to blowers. LOL

Good thing is if I wanted to go blown all I need is the blower and maybe pulleys for less OD mine only go from 50 to 65% combos.Hell motor is my old TA/D motor minus the Whipple charger. Try looking around one of those things.

quote:

Originally posted by Bob Payton:
A bunch of people around here are running street blowers with a single carb. From what I have been told they dont change anything else except lengthen the fuel line and strap the blower on and pick up 3 tenths. Same carb, same converter. I am pretty interested in this. from 3 to 6 psi of boost.

This is literally what I see left and right and people are loving them. It really makes me want to do a combination.

Does anyone think that with a street blower and carb, would a Magnafuel Prostar 500 or equal be enough pump to feed it? Or would you need to switch to a mechanical pump?

I would give APD a call and talk with Randy or John and see what they think. My gut tells me they will want a mechanical pump.

quote:

Originally posted by NC3x58:
With all the hype goin on with these blower setups, what is a typical setup that most people are going to in order to take say a 4.80/90 combination to 4.50/60s? Is it just a simple 671 blower setup from say the blowershop, run 2-4 psi of boost and thats it? Is it any more consistent or is it just a cheaper way to go faster than building a $20K+ motor? Just curious why so many people making the switch.

I use to bracket my 8&10/71’s with a dual Ron’s system. I can say it wasn’t hard on parts at all. Was very consistent 4.2’s with 8 psi. I believe on any engine with boost you will way ahead if start with good parts, especially valvetrain.

If I go back to brackets I will likely go to a blower setup again

quote:

Originally posted by seabass:

quote:

Originally posted by NC3x58:
With all the hype goin on with these blower setups, what is a typical setup that most people are going to in order to take say a 4.80/90 combination to 4.50/60s? Is it just a simple 671 blower setup from say the blowershop, run 2-4 psi of boost and thats it? Is it any more consistent or is it just a cheaper way to go faster than building a $20K+ motor? Just curious why so many people making the switch.

I use to bracket my 8&10/71’s with a dual Ron’s system. I can say it wasn’t hard on parts at all. Was very consistent 4.2’s with 8 psi. I believe on any engine with boost you will way ahead if start with good parts, especially valvetrain.

If I go back to brackets I will likely go to a blower setup again

Was it consistent?

quote:

Originally posted by Big Steve:
After wanting one my whole life and running a blower for the past year, I don't think I will ever NOT run a blower. Their just bad ass

Dave

quote:

Originally posted by Curly1:
Here are my thoughts for what it is worth and why I have not gone to a blower yet.

The blower takes maybe 35% of the horsepower and fuel to turn it. So your crank, rods and pistons are seeing way more power than goes to converter. So if the motor is making 2100 Hp after the blower it is putting around 1400 to the converter.

That extra horsepower shortens the life of the rotating assembly. Plus the blower may be hard on valve springs and valves.

So if you are able to run the number naturally aspirated then that is the way to go in my opinion. But if you need more power the blower will certainly do it.

One other issue is with a blower it is almost like ON or OFF and that makes it hard to get off the line with out spin or wheelies. From what I have been told the prochargers may be a little softer on the hit and pull more on top. Do not know how much difference if any just what I was told.

Curly,
No offense but I think you tried real hard to justify to yourself not going supercharged.
It is not the black hole you are envisioning.

Having run a blown alky car as a fast bracket or local heads up stuff I did not have any nor did I see the issues you are concerned about.

Consistency is possible as long as you avoid the trap of trying to rotate the earth.

Having said that it is amazing how consistent the big boys, including TF can repeat these days using a clutch to boot.

Here is a couple of plusses for a blower.
1: Like a turbo car big strokes and cubic inches are not necessary.
2: Let's say you need 1500 HP to play in your chosen sandbox. It is way less hassle and money to do that with a blower.
3: The torque curve on a blown car is real long.

What is possible?
IN the 70s I had a hard tail 240" car with a 416 cubic inch BB (3.5 stroke)Chevy std deck block and
GM AL heads, powerglide, 8 inch convertor (you read that correctly). Used 8:71.
Aftermarket block and heads did not exist yet.
Results were 7.8s with 2 dominators on gas. Switched to injected alky, got after it a little more and ran low 7.3s

To put this in perspective the Alky NHRA boys were just getting into the 6s. It is a long way from 7.3 to 6.9 but looking back that was doing darn well for a local fellow with dreams larger than his wallet.

The only real issue was fussing with the GM alum heads as the seats would move around. It was a 3 fold problem. Thicker seats were needed, the cams of the day set the valve down too harshly and stronger springs were not available yet. After a year or two those problems went away thanks to the NHRA cars experiencing much the same problems at their level.

With today's off the shelf parts it is darn near a cake walk to run low 6s with a blower.
Slower (less HP) is obviously less expensive and easier on parts.

This message has been edited. Last edited by: Dave Koehler,

quote:

Originally posted by Bob Payton:
A bunch of people around here are running street blowers with a single carb. From what I have been told they dont change anything else except lengthen the fuel line and strap the blower on and pick up 3 tenths. Same carb, same converter. I am pretty interested in this. from 3 to 6 psi of boost.

The old GTO George trick.

quote:

Originally posted by Bob Payton:

quote:

Originally posted by seabass:

quote:

Originally posted by NC3x58:
With all the hype goin on with these blower setups, what is a typical setup that most people are going to in order to take say a 4.80/90 combination to 4.50/60s? Is it just a simple 671 blower setup from say the blowershop, run 2-4 psi of boost and thats it? Is it any more consistent or is it just a cheaper way to go faster than building a $20K+ motor? Just curious why so many people making the switch.

I use to bracket my 8&10/71’s with a dual Ron’s system. I can say it wasn’t hard on parts at all. Was very consistent 4.2’s with 8 psi. I believe on any engine with boost you will way ahead if start with good parts, especially valvetrain.

If I go back to brackets I will likely go to a blower setup again

Was it consistent?

Very much so

I started a post awhile back rate my combo 477bbc b+m 250 powercharger 12psi flat top pistons 643 roller cam patriot freedom 320 heads rons flying toilit on top home made injecter plate I love this combo been running it for awhile now pushes my undercover car at 1925lbs to 4:80s easy I believe Foley just runner up at one of the SFG races running small blower combo secret is out these combo make consistent power and reliable

question for guys with roots style blower.

Are you running a street or race blower? Race being ones the nylon and Teflon stripping and street having no stripping.