ADDING A BLOWER TO A CARB MOTOR?

Coupe Devil · 08-23-2001, 12:23 PM

I was wondering if it would be possible to add a blower to a carb motor? I want to put a small (5psi) on my 306 carb motor. I want to fabricate a spacer to go between the carb and intake that will accept a hoswe from the blower in to the side. Just wondering if it would be possible? I dont want to force air throught the carb I would be afraid the pressure would damage it. Am I totally out of line here. I have a sketch but cant figure out how to post it, also it would have to be like a six inch spacer would the extra length runner help or or hurt torque?
Any ideas? I was also thinking about adding it to my 408 clevor when it gets done.

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'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

Coupe Devil · 08-23-2001, 12:58 PM

I got the hp bug so I called the people at ATIprocharger and they make a kit to add a blower to a carb motor and it DOES forces air through the carb. The tech said all I have to order extra is a kit to change the floats in the Holley double pumper (required) from brass to some filled non-collapsable model and it;s only 35 dollars.
What do you think?

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

90dpscoupe · 08-23-2001, 01:59 PM

My friend was thinking about this too, i showed him a picture in a old car craft mag i have of a blown nova, with a paxton, like a box that mounts over the carb, the nova was going 10.90's with a small block, not bad

my friend also has a 650 double pump so i guess i'll tell him it'll work....good luck and keep posted.

LX XLR8R · 08-23-2001, 02:15 PM

iseen it b4 on a 69 couger with a 351..it was a big red paxton blower..sn93 i think..anyhow it had a box that basically bolted on top of the carb that fed the air threw

------------------
1987 black notch(ex 4 banger)
DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one..
AIM=onesillynotch

juiceman · 08-23-2001, 04:10 PM

everyone make a kit for carb motors. you have to call and ask for it. plus its cheaper than the injected version. around 1300$ the thing you will have to do to the carb besides tune it is change to nitrophyl floats which will cost you 17$ plus the 4 for the gaskets. look at you carb first to make sure you dont already have them. if you dont want to get a blower that feeds through the top of the carb then look at holley's power charger. this is a real blower that the carb sits on top of. it is a little more money at 2500$ for the polished version but look at it. its the same type used on those funny car motors but in a powered down version.

Coupe Devil · 08-23-2001, 04:34 PM

I looked at the Holley kit but I want to maybe up to a 351 later and dont want to have to buy a new blower. I can fabricate all the brackets for this swap. When i build the 351 i am using cleveland heads so I would have to make my own brackets anyway. Do you think that kit is better than a spacer between the carb and intake? Any body know if Paxton has a tech line? All I found was an internet site that didn't take me anywhere.

The WOMAN (how cool is that) that I spoke with at ATI said the 35 dollar kit was the gaskets, floats and possibly new jets I cant remember. Also is a 650 dp big enough on the blown 306 with a stock bottom end? I am not worried about hood clearence on this project it may even go in a Ranger if I find a mid 80's cheap enough with a straight body. She also said the carb had to be Holley which I dont have a problem with at all.

Thanks for the help.

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

juiceman · 08-23-2001, 04:58 PM

the plate between the carb idea wont really work like you think. not a good idea. i dont know what exactly you have done to the motor already. the carb should be fine. big carbs are not needed for 302's. the only thing i dont agree with is the stealth intake. i assume you have stock heads which is fine for a blower. look around at all the companies and get as much info as you can. dont take anyones info as gospel since all companies will tell you what they need to make you buy.
cant seem to find paxton but here are others
powerdyne- 661-723-2800
vortech-805-247-0226
procharger-913-338-2886

Coupe Devil · 08-23-2001, 10:16 PM

Juiceman which intake do you recommend? I dont have the intake and carb yet, I foud a performer rpm and 650 holley dp on the classifieds for like $250 for both. I was just going on the info that some of the locals have given me. I dont think the 306 is going to be a high rpm motor but the 408 will be. I am gonna use a single plane high rise on the 408. It is referred to as the "Track Boss" and is supposed to be for high rpm motors.the only thing i have done to the 302 is bored it .030 over, and ported the exhaust ports. I plan on adding an e-303, a stud girdle, and fully rework the heads and match the intake before I build the 408.

I also dont have to have the blower when I fisrt do the motor. It would just be reeaal nice. I just really want it for when the first key is turned on the 408 clevor.
thanks again

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

90dpscoupe · 08-23-2001, 11:10 PM

Hey the 650 dp should work fine, my friend is spraying a 150 shot, and his 650 holley supplies plenty, he also has a victor jr. intake, and trust me, this combo is wicked, along with longtubes, and cam, ported e7's, but about to go with trickflow's.

Oh and i dont think paxton is in buissness anymore, i think i heard a rumor that vortech bought them out, but not sure.

84_GT350 · 08-24-2001, 03:14 AM

That can be a rather long and headache-filled learning curve. It's hard to get that seal on the carb bonnet just right. That Stealth manifold would work great in an N/A application, but a blower will definitely want to push more air than it can handle. Some companies make blow through carburators also. Carbs specifically designed for forced induction applications. There was a guy I remember seeing in 5.0 magazine that had his carb mounted on the blower inlet pipe. It was definitely odd. Your idea of putting a huge spacer under the carb for the inlet pipe would probably also colapse the floats due to the negative pressure under the car sucking air HARD through the actual carb. Just my $.02

------------------
1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

So I pushed it up to 110,
That flathead motor was about to give in,
I crossed my fingers and prayed to the lord,
Don't let me down you fuct up ford!"

"5-Oh Ford" by The Reverend Horton Heat

Tiger598 · 08-24-2001, 12:47 PM

I guess this is where being old enough to have started on carbed motors in the early 80's when I was a kid comes in handy. The blower has to be set up to force air through the carb. Carbs are very passive fuel metering devices compared to port injection. With the injectors, the computer basically turns a spray of fuel on and off during the intake cycle of that cylinder. The MAF measures how much air is going through the intake, and the computer controls how much fuel to spray -- more air, more fuel.

With carbs, the fuel is basically "pulled" out of the carb by the air rushing past the boosters (the round rings you see in the middle of each barrel of the carb). The fuel shears off the bottom of the boosters in very small droplets (vapor, really), creating the fuel/air mix. The faster the air goes by, the more fuel is pulled out of the carb. More air, more fuel.

That's why running the blower through a spacer under the carb won't work -- adding more air after the carb would result in a very lean condition. If the extra air didn't pass over the boosters, the right amount of fuel wouldn't be pulled out.

Good luck - it's gonna be a lot of fun, whatever you decide to do.

If it was me, I'd cut a hole in my hood and stick a big ol' Weiand 8-71 on top of that motor. Those things are made in two pieces -- one is the expensive compressor part, the other is a less expensive lower manifold. You might be able to just change out the lower manifold when you swapped to the 351, provided you could find one made for a Clevor.

Later,

B

Coupe Devil · 08-24-2001, 01:07 PM

Ok I was told I cant get a 8-71 for a 302. That may not be true? I understand why the air should go through the top of the cab now but wouldnt haveing an 8-71 be the same as my "spacer Idea" since the carb is on top of the blower. I have a greater availability of performance parts for a 460, I can build a HOT 460 short block for $1000. Using a buddys spare parts. Would going with the 8-71, all I would have to change is the lower intake to go to a 460?

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

Tiger598 · 08-24-2001, 01:28 PM

Truth be told, I haven't checked into the 8-71 -- the 6-71 has to be available. It's the most common of the GMC-type blowers.

That GMC blower works 'cause it's sucking air down through the carb and picking up fuel, versus blowing "dry" air in under it. Actually improves the dispersion of the fuel/air mix as it's spinning through the compressor rotors.

460. Now we're talkin' arh arh arh arh. There is no replacement for displacement, as they say. I've never built a big block, so I'm not sure if blowers are interchangeable big block to smallblock. Much bigger difference in the distance between heads and ports. I'd call the folks at Weiand, or one of the other manufacturers that makes that type blower.

If you do talk to them, you should check all my info on blower interchangeability -- long time since I sold that car.

[This message has been edited by Tiger598 (edited 08-24-2001).]

Coupe Devil · 08-24-2001, 03:22 PM

Thanks for the help guys, I hope I can get started on this thing soon. I'm gettin anxious just drivin a 4 banger every day. I hope I can have it on the track buy the end of next season. I like the local track. Thier classes are as follows: Slower than a 7.50 can be street class, 7.50 to 6.50 is Sportsman, and faster than a 6.50 is Pro. I like it because it's run what you brung. Hopefully i be able to suprise some people when it gets done.

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

Gearbanger · 08-25-2001, 11:25 AM

Go to Yahoo Groups/Mailing list (formally EGroups) and in the search section type in "Blow-thru". There are many people on this group blowing superchargers/turbos thru carbs w/ no problems. I personally have two friends doing this now. One has a 440 Mopar w/ ATI P-600 the other has a Chevy 355 w/ ATI D-1.

Hope this helps. Teddy Popee

RUSTANG · 08-28-2001, 11:12 AM

Piping the air in under the carb will not work. The air will be forced out the hole with the least restriction...right out your carb! The blower either needs to pull air through the carb or push it through the carb.

Mike

Dark Knight · 08-28-2001, 11:44 AM

http://www.bigalstoybox.com/ford.html

also check out blower drive service.. http://www.BlowerDriveService.com/

a GMC blower is the same for any car, just a different intake a pulleys.. and there's no need for an 8-71 on a small block... ;-)

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives BBK shorties
stock cam, 1.7's
13.85@102.5
and a '68 stang that WAS nasty ;-)

Coupe Devil · 08-28-2001, 04:03 PM

I went to both of those sites and Damn those things are alot cheaper than I thought. For some reason I thought an 8-71 was like 5 grand or something. I havechanged my mind about building a full out drag car after visiting these sites. Can you imagine a 460 c.i.d. powered 93 notch with 2 fours and an 8-71 exploding (maybe not such a good choice of words but) through the hood. I CAN. Oh dad will be so proud, Mom won't like the idea much but she will get over it. Now where makes the best mounts and accesories for this application. I need motor and tranny mounts and a tranny crossmember for a c-6. I could also use a front engine plate, I guess.

------------------
'93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

Dark Knight · 08-28-2001, 08:52 PM

http://www.mspmall.com/ddautospec/swapkits.html

there are quite a few places that have swap kits... pretty much a bolt in.. ;-)

------------------
84 convt,'95 302,AFR's, performer
3.55's, underdrives BBK shorties
stock cam, 1.7's
13.85@102.5
and a '68 stang that WAS nasty ;-)

MiracleMax · 08-29-2001, 12:07 AM

There are 2 ways to carb a centrifugal type blower.

A. Blow through
B. Pull through

The easiest is a pull through system, you mount the carb up stream of the blower and let it work like nature intended (@ about 120% volumetric effciency). Lets see here that'd be 306 x 6500 rpm / 3456 x 120% = 690 cfm or a bit bigger and jet accordingly.

A blow through system is a bit tricker. the easiest way to do this would be to mount the carb in a pressure box which negates the need for shaft seals and the like since the carb is operating under equal pressure on both sides obviating the need for extra sealing and simplifying tuning as compared to an exposed carb blow through system. Simply bolting some sort of plenum to the head of the carb makes things super difficult since you've got a positive pressure system flowing through a device designed to operate in the presence of negative pressure. Just like an FMU you have to boost reference the carb for the blower along with the aformentioned need to seal the carb. However a blow through system has its merits mainly from a safety stand point. With a pull through system, fuel is drawn from the carb all the way through the blower and then into the engine. Problem is without some kind of pressure relief on the manifold (a Wilson spacer with blowout protection would be handy here)a backfire travels from the intake all the way back through the blower and up to the carb (lotsa fuel and air to burn there). If the engine is running the
best analogy I can make here is to get on a bike and go down hill pedaling as fast as you can then stick your foot into the spokes on the front wheel and see what happens! Anyway you get the idea. With a blow through system fuel stops at the carb and lessens the damage which could occur. On the flip side, a pull through system gains the evaporative cooling effect of all that fuel turning into a vapor which potentially could add a few ponies and possibly increase the reliability of the blower since everything south of the carb would operate slightly cooler or allow more aggresive timing or compression or both.

08-23-2001, 12:23 PM	#1
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	ADDING A BLOWER TO A CARB MOTOR? I was wondering if it would be possible to add a blower to a carb motor? I want to put a small (5psi) on my 306 carb motor. I want to fabricate a spacer to go between the carb and intake that will accept a hoswe from the blower in to the side. Just wondering if it would be possible? I dont want to force air throught the carb I would be afraid the pressure would damage it. Am I totally out of line here. I have a sketch but cant figure out how to post it, also it would have to be like a six inch spacer would the extra length runner help or or hurt torque? Any ideas? I was also thinking about adding it to my 408 clevor when it gets done. ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

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08-23-2001, 12:58 PM	#2
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	I got the hp bug so I called the people at ATIprocharger and they make a kit to add a blower to a carb motor and it DOES forces air through the carb. The tech said all I have to order extra is a kit to change the floats in the Holley double pumper (required) from brass to some filled non-collapsable model and it;s only 35 dollars. What do you think? ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-23-2001, 01:59 PM	#3
90dpscoupe Registered Member Join Date: Jun 2000 Location: sanantonio, Tx, usa Posts: 1,407	My friend was thinking about this too, i showed him a picture in a old car craft mag i have of a blown nova, with a paxton, like a box that mounts over the carb, the nova was going 10.90's with a small block, not bad my friend also has a 650 double pump so i guess i'll tell him it'll work....good luck and keep posted.

08-23-2001, 02:15 PM	#4
LX XLR8R Dirk Diggler Join Date: Feb 1999 Location: SLOATSBURG, NY Posts: 1,931	iseen it b4 on a 69 couger with a 351..it was a big red paxton blower..sn93 i think..anyhow it had a box that basically bolted on top of the carb that fed the air threw ------------------ 1987 black notch(ex 4 banger) DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one.. AIM=onesillynotch

08-23-2001, 04:10 PM	#5
juiceman Registered Member Join Date: Jan 2001 Location: ny Posts: 197	everyone make a kit for carb motors. you have to call and ask for it. plus its cheaper than the injected version. around 1300$ the thing you will have to do to the carb besides tune it is change to nitrophyl floats which will cost you 17$ plus the 4 for the gaskets. look at you carb first to make sure you dont already have them. if you dont want to get a blower that feeds through the top of the carb then look at holley's power charger. this is a real blower that the carb sits on top of. it is a little more money at 2500$ for the polished version but look at it. its the same type used on those funny car motors but in a powered down version.

08-23-2001, 04:34 PM	#6
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	I looked at the Holley kit but I want to maybe up to a 351 later and dont want to have to buy a new blower. I can fabricate all the brackets for this swap. When i build the 351 i am using cleveland heads so I would have to make my own brackets anyway. Do you think that kit is better than a spacer between the carb and intake? Any body know if Paxton has a tech line? All I found was an internet site that didn't take me anywhere. The WOMAN (how cool is that) that I spoke with at ATI said the 35 dollar kit was the gaskets, floats and possibly new jets I cant remember. Also is a 650 dp big enough on the blown 306 with a stock bottom end? I am not worried about hood clearence on this project it may even go in a Ranger if I find a mid 80's cheap enough with a straight body. She also said the carb had to be Holley which I dont have a problem with at all. Thanks for the help. ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-23-2001, 04:58 PM	#7
juiceman Registered Member Join Date: Jan 2001 Location: ny Posts: 197	the plate between the carb idea wont really work like you think. not a good idea. i dont know what exactly you have done to the motor already. the carb should be fine. big carbs are not needed for 302's. the only thing i dont agree with is the stealth intake. i assume you have stock heads which is fine for a blower. look around at all the companies and get as much info as you can. dont take anyones info as gospel since all companies will tell you what they need to make you buy. cant seem to find paxton but here are others powerdyne- 661-723-2800 vortech-805-247-0226 procharger-913-338-2886

08-23-2001, 10:16 PM	#8
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	Juiceman which intake do you recommend? I dont have the intake and carb yet, I foud a performer rpm and 650 holley dp on the classifieds for like $250 for both. I was just going on the info that some of the locals have given me. I dont think the 306 is going to be a high rpm motor but the 408 will be. I am gonna use a single plane high rise on the 408. It is referred to as the "Track Boss" and is supposed to be for high rpm motors.the only thing i have done to the 302 is bored it .030 over, and ported the exhaust ports. I plan on adding an e-303, a stud girdle, and fully rework the heads and match the intake before I build the 408. I also dont have to have the blower when I fisrt do the motor. It would just be reeaal nice. I just really want it for when the first key is turned on the 408 clevor. thanks again ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-23-2001, 11:10 PM	#9
90dpscoupe Registered Member Join Date: Jun 2000 Location: sanantonio, Tx, usa Posts: 1,407	Hey the 650 dp should work fine, my friend is spraying a 150 shot, and his 650 holley supplies plenty, he also has a victor jr. intake, and trust me, this combo is wicked, along with longtubes, and cam, ported e7's, but about to go with trickflow's. Oh and i dont think paxton is in buissness anymore, i think i heard a rumor that vortech bought them out, but not sure.

08-24-2001, 03:14 AM	#10
84_GT350 Registered Member Join Date: Apr 1999 Location: Overland Park, KS, USA Posts: 1,631	That can be a rather long and headache-filled learning curve. It's hard to get that seal on the carb bonnet just right. That Stealth manifold would work great in an N/A application, but a blower will definitely want to push more air than it can handle. Some companies make blow through carburators also. Carbs specifically designed for forced induction applications. There was a guy I remember seeing in 5.0 magazine that had his carb mounted on the blower inlet pipe. It was definitely odd. Your idea of putting a huge spacer under the carb for the inlet pipe would probably also colapse the floats due to the negative pressure under the car sucking air HARD through the actual carb. Just my $.02 ------------------ 1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s So I pushed it up to 110, That flathead motor was about to give in, I crossed my fingers and prayed to the lord, Don't let me down you fuct up ford!" "5-Oh Ford" by The Reverend Horton Heat

08-24-2001, 12:47 PM	#11
Tiger598 Registered Member Join Date: Aug 2001 Location: Southeastern PA Posts: 5	I guess this is where being old enough to have started on carbed motors in the early 80's when I was a kid comes in handy. The blower has to be set up to force air through the carb. Carbs are very passive fuel metering devices compared to port injection. With the injectors, the computer basically turns a spray of fuel on and off during the intake cycle of that cylinder. The MAF measures how much air is going through the intake, and the computer controls how much fuel to spray -- more air, more fuel. With carbs, the fuel is basically "pulled" out of the carb by the air rushing past the boosters (the round rings you see in the middle of each barrel of the carb). The fuel shears off the bottom of the boosters in very small droplets (vapor, really), creating the fuel/air mix. The faster the air goes by, the more fuel is pulled out of the carb. More air, more fuel. That's why running the blower through a spacer under the carb won't work -- adding more air after the carb would result in a very lean condition. If the extra air didn't pass over the boosters, the right amount of fuel wouldn't be pulled out. Good luck - it's gonna be a lot of fun, whatever you decide to do. If it was me, I'd cut a hole in my hood and stick a big ol' Weiand 8-71 on top of that motor. Those things are made in two pieces -- one is the expensive compressor part, the other is a less expensive lower manifold. You might be able to just change out the lower manifold when you swapped to the 351, provided you could find one made for a Clevor. Later, B

08-24-2001, 01:07 PM	#12
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	Ok I was told I cant get a 8-71 for a 302. That may not be true? I understand why the air should go through the top of the cab now but wouldnt haveing an 8-71 be the same as my "spacer Idea" since the carb is on top of the blower. I have a greater availability of performance parts for a 460, I can build a HOT 460 short block for $1000. Using a buddys spare parts. Would going with the 8-71, all I would have to change is the lower intake to go to a 460? ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-24-2001, 01:28 PM	#13
Tiger598 Registered Member Join Date: Aug 2001 Location: Southeastern PA Posts: 5	Truth be told, I haven't checked into the 8-71 -- the 6-71 has to be available. It's the most common of the GMC-type blowers. That GMC blower works 'cause it's sucking air down through the carb and picking up fuel, versus blowing "dry" air in under it. Actually improves the dispersion of the fuel/air mix as it's spinning through the compressor rotors. 460. Now we're talkin' arh arh arh arh. There is no replacement for displacement, as they say. I've never built a big block, so I'm not sure if blowers are interchangeable big block to smallblock. Much bigger difference in the distance between heads and ports. I'd call the folks at Weiand, or one of the other manufacturers that makes that type blower. If you do talk to them, you should check all my info on blower interchangeability -- long time since I sold that car. [This message has been edited by Tiger598 (edited 08-24-2001).]

08-24-2001, 03:22 PM	#14
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	Thanks for the help guys, I hope I can get started on this thing soon. I'm gettin anxious just drivin a 4 banger every day. I hope I can have it on the track buy the end of next season. I like the local track. Thier classes are as follows: Slower than a 7.50 can be street class, 7.50 to 6.50 is Sportsman, and faster than a 6.50 is Pro. I like it because it's run what you brung. Hopefully i be able to suprise some people when it gets done. ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-25-2001, 11:25 AM	#15
Gearbanger Registered Member Join Date: Oct 1998 Location: Birmingham, Alabama, USA Posts: 12	Go to Yahoo Groups/Mailing list (formally EGroups) and in the search section type in "Blow-thru". There are many people on this group blowing superchargers/turbos thru carbs w/ no problems. I personally have two friends doing this now. One has a 440 Mopar w/ ATI P-600 the other has a Chevy 355 w/ ATI D-1. Hope this helps. Teddy Popee

08-28-2001, 11:12 AM	#16
RUSTANG Registered Member Join Date: Jan 1999 Location: Dale City Va. Posts: 516	Piping the air in under the carb will not work. The air will be forced out the hole with the least restriction...right out your carb! The blower either needs to pull air through the carb or push it through the carb. Mike

08-28-2001, 11:44 AM	#17
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	http://www.bigalstoybox.com/ford.html also check out blower drive service.. http://www.BlowerDriveService.com/ a GMC blower is the same for any car, just a different intake a pulleys.. and there's no need for an 8-71 on a small block... ;-) ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives BBK shorties stock cam, 1.7's 13.85@102.5 and a '68 stang that WAS nasty ;-)

08-28-2001, 04:03 PM	#18
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	I went to both of those sites and Damn those things are alot cheaper than I thought. For some reason I thought an 8-71 was like 5 grand or something. I havechanged my mind about building a full out drag car after visiting these sites. Can you imagine a 460 c.i.d. powered 93 notch with 2 fours and an 8-71 exploding (maybe not such a good choice of words but) through the hood. I CAN. Oh dad will be so proud, Mom won't like the idea much but she will get over it. Now where makes the best mounts and accesories for this application. I need motor and tranny mounts and a tranny crossmember for a c-6. I could also use a front engine plate, I guess. ------------------ '93 lx notch 4 banger (drive it to work currently), 89' 4banger in prep for all out drag car. Using the 306, 8.8 posi, 4.10's, summit rear cover. Future Mods granatelli lift bars, bbk uppers, Flex-a-lite elec. fan, cowl hood, wieand stealth intake, holley 650 d.p., built c-4 or c-6, e-303, 10 inch wheels in the back with slicks, skinnies up front, pulleys, full autometer guages, msd box, mallory unilite dist, and coil, custom headers, rear seat delete, aftermarket front seats, roll cage

08-28-2001, 08:52 PM	#19
Dark Knight Registered Member Join Date: Oct 1998 Location: Az Posts: 854	http://www.mspmall.com/ddautospec/swapkits.html there are quite a few places that have swap kits... pretty much a bolt in.. ;-) ------------------ 84 convt,'95 302,AFR's, performer 3.55's, underdrives BBK shorties stock cam, 1.7's 13.85@102.5 and a '68 stang that WAS nasty ;-)

08-29-2001, 12:07 AM	#20
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	There are 2 ways to carb a centrifugal type blower. A. Blow through B. Pull through The easiest is a pull through system, you mount the carb up stream of the blower and let it work like nature intended (@ about 120% volumetric effciency). Lets see here that'd be 306 x 6500 rpm / 3456 x 120% = 690 cfm or a bit bigger and jet accordingly. A blow through system is a bit tricker. the easiest way to do this would be to mount the carb in a pressure box which negates the need for shaft seals and the like since the carb is operating under equal pressure on both sides obviating the need for extra sealing and simplifying tuning as compared to an exposed carb blow through system. Simply bolting some sort of plenum to the head of the carb makes things super difficult since you've got a positive pressure system flowing through a device designed to operate in the presence of negative pressure. Just like an FMU you have to boost reference the carb for the blower along with the aformentioned need to seal the carb. However a blow through system has its merits mainly from a safety stand point. With a pull through system, fuel is drawn from the carb all the way through the blower and then into the engine. Problem is without some kind of pressure relief on the manifold (a Wilson spacer with blowout protection would be handy here)a backfire travels from the intake all the way back through the blower and up to the carb (lotsa fuel and air to burn there). If the engine is running the best analogy I can make here is to get on a bike and go down hill pedaling as fast as you can then stick your foot into the spokes on the front wheel and see what happens! Anyway you get the idea. With a blow through system fuel stops at the carb and lessens the damage which could occur. On the flip side, a pull through system gains the evaporative cooling effect of all that fuel turning into a vapor which potentially could add a few ponies and possibly increase the reliability of the blower since everything south of the carb would operate slightly cooler or allow more aggresive timing or compression or both.