Pro-systems carb arrived!
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,022
Likes: 6
From: CT
I am having tuning issues with my Holley 850. I have been pointed to a pro systems. I was going to ask how you could tell yer AFR, now I see how with the gauge you have.
Does the throttle linkage match a Holley? It looks similar from your pic above. I would need that to mount my existing bracketry.
Great video......
Does the throttle linkage match a Holley? It looks similar from your pic above. I would need that to mount my existing bracketry.
Great video......
http://www.prosystemsracing.com/index1.html
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,022
Likes: 6
From: CT
You need to be smarter than the moron on the phone telling you to stay smaller with a stick car. That is even wrong for a non-supercharged car. Super chargers at 10 psi is like doubling your cubic inches. So a 350 becomes 700 ci. in the amount of CFM flow through the carb
That is why you see dual 750's on a blower motor. Previously you had a 750 mighty demon. It probably flowed around 800 cfm with annular booster.
You need much more cfm. I would return it and argue that you got dupped by a dumb A$$
Carbs can maintain the most linear A/F ratios when operated within air flow parameters. You don't want the carb restricting flow to the supercharger.
Oh Ya! aren't line locks crowd pleasers?
That is why you see dual 750's on a blower motor. Previously you had a 750 mighty demon. It probably flowed around 800 cfm with annular booster.
You need much more cfm. I would return it and argue that you got dupped by a dumb A$$
Carbs can maintain the most linear A/F ratios when operated within air flow parameters. You don't want the carb restricting flow to the supercharger.
Oh Ya! aren't line locks crowd pleasers?
I was confused on the CFM from pro-system as well.
I found a formula online for determining best CFM for a supercharged motor:
(CID X RPM / 3456) X (boost/14.7 + 1) = CFM
for 350ci @6000rpm peak and 7psi it came out to.. 896.86cfm
at 9psi is about 950cfm
When I was deciding on a new carb I called Holley and Quick Fuel. Holley told me to use a 950hp which the tech said flowed (820-830cfm)
The Quick Fuel tech told me not go over 750cfm, even though my last 750cfm demon seemed too small.
I researched pro-systems and was told that the builder starts with an HP body and can build it anyway from 600cfm-1000cfm. Each carb is suppose to be custom built and matched too the motor's exact specs. I was told that my "program called for ~785cfm" I questioned the builder on the phone about going bigger and he ensured me that it was not needed. Also he was against annular booster for my app???
Car seems to run pretty good now, I'll see what it does on dyno in a few weeks. Pro-systems has great customer service and I could probably send it back and have it reworked if I asked.
Burning Brakes
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
custom built Eaton 12 bolt 4 series case with 3.73 gears.
heat treated 10/17 spiders (30 spline)
custom tuned/polished posi set up
ARP ring gear bolts
Toms Diff steel bearing cap
Billet driveshaft yoke
HD rear cover
Solid pinion sleeve
30 spline Heat treated Toms Inner axles
3.5" Halfshafts
Tom's (31 spline) outer axles with 1/2" wheel studs
Solid rear diff crossmember mounts and traction bar.
Its overkill for my current power level but I eventually want to do a bigger motor and a procharger set up.
heat treated 10/17 spiders (30 spline)
custom tuned/polished posi set up
ARP ring gear bolts
Toms Diff steel bearing cap
Billet driveshaft yoke
HD rear cover
Solid pinion sleeve
30 spline Heat treated Toms Inner axles
3.5" Halfshafts
Tom's (31 spline) outer axles with 1/2" wheel studs
Solid rear diff crossmember mounts and traction bar.
Its overkill for my current power level but I eventually want to do a bigger motor and a procharger set up.
Its never overkill in my opinion, its more like buying an insurance policy. Some people believe in only going as far as needed. One of my teachers years ago had a saying that works for a lot of things. he used to say how many times can you bend a coat hanger? The answer is unkown as it could break on the first bend, it could also go 10 bends. The idea of it is that the higher quality and stronger something is built the longer it will last. Eventually everything will break why not try to make it good enough to last. Nice build hopefully you video tape dyno run that motor sounds killer.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I was confused on the CFM from pro-system as well.
I found a formula online for determining best CFM for a supercharged motor:
(CID X RPM / 3456) X (boost/14.7 + 1) = CFM
for 350ci @6000rpm peak and 7psi it came out to.. 896.86cfm
at 9psi is about 950cfm
When I was deciding on a new carb I called Holley and Quick Fuel. Holley told me to use a 950hp which the tech said flowed (820-830cfm)
The Quick Fuel tech told me not go over 750cfm, even though my last 750cfm demon seemed too small.
.
I found a formula online for determining best CFM for a supercharged motor:
(CID X RPM / 3456) X (boost/14.7 + 1) = CFM
for 350ci @6000rpm peak and 7psi it came out to.. 896.86cfm
at 9psi is about 950cfm
When I was deciding on a new carb I called Holley and Quick Fuel. Holley told me to use a 950hp which the tech said flowed (820-830cfm)
The Quick Fuel tech told me not go over 750cfm, even though my last 750cfm demon seemed too small.
.
