Jetting/tuning For Procharger setup
04-08-2004, 10:54 AM
#11
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Thanks for all of the replies guys. I 'm almost certain I need to stay clear of the Procharger setup until I can afford fuel injection!
Does anyone know what Nickerson charges to modify a carb for this type of setup? Or do you have to buy one of his carbs outright?
I have rebuilt and modified quite a few Holley carbs in the past and there is only so much you can do to them.
I'm thinking that Dean probably bores out the Power circuit orfices to add the necessary enrichment there under boost as opposed to having the main circuit overly rich to compensate for the added airflow the blower produces. This way you get A/F enrichment only when you need it - under boost. This would mean that you don't get flooding at part throttle because you have such big main jets. ( I guess the only thing to do is keep it W.O.T.!!)
BTW: Holley makes at least a couple of different types of PowerValves. The "window" type with the square holes is highest flowing one. This type always comes in Holley Trick Kits. Anyone know what type and what In. Hg. rating the P/V in the Nickerson carbs?
I know I am oversimplifying, but after all, a Holley carb is a pretty simple piece of equipment, is it not?
I'm going to try jetting it up rich myself at first (if I buy the P/charger) and be careful and I'll let you all know how it goes.
Does anyone know what Nickerson charges to modify a carb for this type of setup? Or do you have to buy one of his carbs outright?
I have rebuilt and modified quite a few Holley carbs in the past and there is only so much you can do to them.
I'm thinking that Dean probably bores out the Power circuit orfices to add the necessary enrichment there under boost as opposed to having the main circuit overly rich to compensate for the added airflow the blower produces. This way you get A/F enrichment only when you need it - under boost. This would mean that you don't get flooding at part throttle because you have such big main jets. ( I guess the only thing to do is keep it W.O.T.!!)
BTW: Holley makes at least a couple of different types of PowerValves. The "window" type with the square holes is highest flowing one. This type always comes in Holley Trick Kits. Anyone know what type and what In. Hg. rating the P/V in the Nickerson carbs?
I know I am oversimplifying, but after all, a Holley carb is a pretty simple piece of equipment, is it not?
I'm going to try jetting it up rich myself at first (if I buy the P/charger) and be careful and I'll let you all know how it goes.
04-08-2004, 04:13 PM
#13
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If you have a carb already, he only charges like 350 or so to modify.
To buy a carb from him is around 6-7 bucks. But thats with all the goodies. 4 corner idle etc.
Thats if I remember correctly.
My 2 carbs, pump, reg and fittings was around 1850.
DAVE
To buy a carb from him is around 6-7 bucks. But thats with all the goodies. 4 corner idle etc.
Thats if I remember correctly.
My 2 carbs, pump, reg and fittings was around 1850.
DAVE
04-08-2004, 08:31 PM
#14
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Dean quoted me 1050 EACH for a carb and 550 EACH to do mine. This was last month.
Maybe if I figure out what he's doing I'll have a new career,,JUST KIDDING GUYS, I won't blaspheme on this board,,LONG LIVE DEAN!!
Maybe if I figure out what he's doing I'll have a new career,,JUST KIDDING GUYS, I won't blaspheme on this board,,LONG LIVE DEAN!!
04-13-2004, 12:09 PM
#16
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Here's an update guys:
As luck would have it, I got water in my carb somehow and had to pull it down and rebuild it this weekend. I was pleasantly surprised to find that the carb is loaded with all sort of mods and good parts, including the following:
1.Dual Power Valves. These suckers actually have 4 large rectangular orifices in them. I don't know where Bill Mitchell finds them but I would definitely like to find some spares. They were screwed up so I had to replace them with the Holley High Performance 2 Rect. Hole types.Also the holes from the power cavity to the main jet well are definitely opened up to like 0.080" You can compare them to a regular 4bbl double pump and there is a noticeable visible difference.
2.Vent Whistles to prevent fuel slosh.
3.Chamfered jets. They were actually # 78s (although the Dyno sheet said 74s) on all4 corners. They look different from the Holley standard jet in that they are chamfered on both sides of the hole. This I believe will improve flow so they probably could flow like say an # 80 or so.
4. 4 corner idle circuits
5. Downleg ("dogleg") boosters with the bottom machined out (for stronger booster signal?)
6. Brass floats. I read somewhere that these can't be used with positive displacement forced induction because the added pressure will collapse the floats (they're hollow) Anyone know anything about this?
7. The needle and seat assembly appeared to be different from the standard Holley Trick Kit issue and they look to be larger. BTW: Any ideas on whether this should be changed for single carb blower applications? The standard High Performance Holley Viton seat is ).110". Holley does make a . 150" Titanium seat assembly that I want to get. I think that should solve any fuel delivery problem I have there!
8. Quick Change float bowls for easy access to the jets (you have to use a Holley jet tool though).
All in all this seems to be a nicely modified carb to begin with so I am convinced that I will stick with it (with
richer mains) and jet it carefully.
BTW: It is important to note that the Power circuit is the circuit which Holley designed to feed the carb at W.O.T. as opposed to the main circuit which feeds the mid range. If you talk to most Holley tuning gurus they'll tell you that you should jet the mains for economical cruise and then select a power valve to compliment your WOT use. BUT power valves are only designed such that they control the WOT circuit "tip in" point, NOT fuel calibration. The orifices behind the power valve actually control fuel calibration. Brad Urban use to make a kit which included a drill bit and tap set and a number of screw-in jets to allow you to drill and tap these orifices and then jet them for your particular application. I don't know if he still offers this kit but I'll try to find out and will keep you all posted.
That said I think I need to start looking for a Procharger now...
As luck would have it, I got water in my carb somehow and had to pull it down and rebuild it this weekend. I was pleasantly surprised to find that the carb is loaded with all sort of mods and good parts, including the following:
1.Dual Power Valves. These suckers actually have 4 large rectangular orifices in them. I don't know where Bill Mitchell finds them but I would definitely like to find some spares. They were screwed up so I had to replace them with the Holley High Performance 2 Rect. Hole types.Also the holes from the power cavity to the main jet well are definitely opened up to like 0.080" You can compare them to a regular 4bbl double pump and there is a noticeable visible difference.
2.Vent Whistles to prevent fuel slosh.
3.Chamfered jets. They were actually # 78s (although the Dyno sheet said 74s) on all4 corners. They look different from the Holley standard jet in that they are chamfered on both sides of the hole. This I believe will improve flow so they probably could flow like say an # 80 or so.
4. 4 corner idle circuits
5. Downleg ("dogleg") boosters with the bottom machined out (for stronger booster signal?)
6. Brass floats. I read somewhere that these can't be used with positive displacement forced induction because the added pressure will collapse the floats (they're hollow) Anyone know anything about this?
7. The needle and seat assembly appeared to be different from the standard Holley Trick Kit issue and they look to be larger. BTW: Any ideas on whether this should be changed for single carb blower applications? The standard High Performance Holley Viton seat is ).110". Holley does make a . 150" Titanium seat assembly that I want to get. I think that should solve any fuel delivery problem I have there!
8. Quick Change float bowls for easy access to the jets (you have to use a Holley jet tool though).
All in all this seems to be a nicely modified carb to begin with so I am convinced that I will stick with it (with
richer mains) and jet it carefully.
BTW: It is important to note that the Power circuit is the circuit which Holley designed to feed the carb at W.O.T. as opposed to the main circuit which feeds the mid range. If you talk to most Holley tuning gurus they'll tell you that you should jet the mains for economical cruise and then select a power valve to compliment your WOT use. BUT power valves are only designed such that they control the WOT circuit "tip in" point, NOT fuel calibration. The orifices behind the power valve actually control fuel calibration. Brad Urban use to make a kit which included a drill bit and tap set and a number of screw-in jets to allow you to drill and tap these orifices and then jet them for your particular application. I don't know if he still offers this kit but I'll try to find out and will keep you all posted.
That said I think I need to start looking for a Procharger now...
04-14-2004, 10:05 AM
#19
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See, that's what I'm saying - if you have a carb thats already highly modified why should someone have to pay even $500.00 to have a few orifices in it modified? The other thing is, all of the fuel metering for all three circuits (idle, main and power) is done in the metering blocks. the only other metered orifices are the idle and high speed air bleeds which are located above the venturi in the main body. Most people don't even want to touch these unless you're dealing with a Dominator and there is a high speed mixture problem.
It must be that someone in the carb business could sell modified metering blocks to us poorer folk for say even $75- 100 which should take care of any fuel delivery problems we might encounter with the Procharger setup.
BTW: Cooltoys61: You might want to get a Secondary metering block with the power valve circuit in it so that you will have the ability to tune for the right fuel enrichment at higher cruise speeds when the secondaries are partially open.
It must be that someone in the carb business could sell modified metering blocks to us poorer folk for say even $75- 100 which should take care of any fuel delivery problems we might encounter with the Procharger setup.
BTW: Cooltoys61: You might want to get a Secondary metering block with the power valve circuit in it so that you will have the ability to tune for the right fuel enrichment at higher cruise speeds when the secondaries are partially open.
