Finally got my carb'd LS project on the street
#83
Hmmmm, its odd that our two carbs are set up so similarly for use at such different altitudes. Hopefully that means that my new toys were a good investment. Probably will need to invest in some airbleed blanks and drill bits too eventually.
I will definately do that. I know the plugs look like it idles rich for sure, but when I lean it out just a little bit it wants to die after I let off the throttle. Are you thinking that's and air bleed issue? Like I said.....I've got a lot to learn about the finer points of fine tuning a carb, but I look forward to learning as I go.
I will definately do that. I know the plugs look like it idles rich for sure, but when I lean it out just a little bit it wants to die after I let off the throttle. Are you thinking that's and air bleed issue? Like I said.....I've got a lot to learn about the finer points of fine tuning a carb, but I look forward to learning as I go.
#84
Old School Heavy
iTrader: (16)
I will definately do that. I know the plugs look like it idles rich for sure, but when I lean it out just a little bit it wants to die after I let off the throttle. Are you thinking that's and air bleed issue? Like I said.....I've got a lot to learn about the finer points of fine tuning a carb, but I look forward to learning as I go.
Their answer to the situation was to just richen it until the stumble went away and ignore what the A/F ratio meter said. Patrick said: "that is just what the car wants" LOL. My car wants black plugs, combustion chamber, exhaust and an idle that would make Chuck Norris cry? I don't think so.
They are always very friendly and try to help, but my impression is that they are great at race carbs, but have no abilities on street cars that need their carb to run clean.
My home built 750 HP will idle at any A/F ratio without tip in problems and cruises at 14 t0 14.5:1 no problem. The Pro Systems carbs will not.
My next thing is to reduce the size of the fuel idle feed restrictor in the metering plate. I want to try this because no matter how big I go on the idle air bleeds, the car wants no more than 5/8 of a turn out on the idle mixture screws. In my mind, this says the fuel idle feed restrictors are too big. I will either have to put in a piece of wire or drill and tap them for a plug that I can re-drill. In retrospect, I wish I would have bought a quick fuel with replaceable bleeds.
#90
Ooops, you're right. I forgot I even had those. I guess I'll just need some machinist's drill bits. Where's a good place to look for that kind of stuff? Is that something Harbor Freight might carry?
The rest of this conversation is interesting. I'm sure I'll be going through all of the same issues, so I'm glad to learn from you guys' experiences. When I last dealt with carbs 15yrs ago, I was lucky to set the floats and idle speed. After that, if it would burn the tires when I dumped the clutch.....it was tuned! LOL. Since then all my tuning experience has been with a laptop and wideband.
The rest of this conversation is interesting. I'm sure I'll be going through all of the same issues, so I'm glad to learn from you guys' experiences. When I last dealt with carbs 15yrs ago, I was lucky to set the floats and idle speed. After that, if it would burn the tires when I dumped the clutch.....it was tuned! LOL. Since then all my tuning experience has been with a laptop and wideband.
#96
Thanks man! I just updated my build thread with a few new things today. Bottom line....I got my factory seats modified for my harnesses to go through and I installed my wideband. I got my idle AFR pretty dialed in for now, but haven't driven the car (other than out into the street and back) with it leaned out. Still lots of work and testing to do. I'm most curious about my WOT AFR.
#97
I had a chance to do some logging with my wideband today. I got the idle circuit dialed in nicely around 14.5:1 in gear (and about 13.8 in park/neutral). So I did some driving today to work on the rest. It seems like it transitions from the idle circuit to the main well somewhere between 2800 and 3100 RPM, depending on the amount of load. It goes fat once it transitions to the main well going from around 14.5 to 12.5 once it fully transitions. But the WOT AFR looked great at around 12.8-13.0.
So as an experiment, I jetted the mains down from 76 to 73. This brought the main well cruise from 12.5 to around 13.1 or so. I also did a quick WOT blast and saw around 13.2 or 13.3 up top. This obviously came as no surprise since I took away from the overall jetting. Obviously I'll have to jet up the secondaries to bring the WOT AFR back into line.
But here's my question I guess. Am I on the right track? I mean it seems like I still need to go down a few more numbers on the mains maybe down to 70 or so. That would be a total reduction of 6 jet sizes. I would then think I would need to go up that same amount on the secondaries to compinsate.....and that would put me at 92 or so. That just seems like a huge spread in jetting.
I know ultimately, the answer would be to leave the secondary jetting alone and increase the PVCR size, but since that isn't an option for me right now without drilling, can I get there with the jetting? I just don't know how much of a jet spread is acceptable. Any input?
So as an experiment, I jetted the mains down from 76 to 73. This brought the main well cruise from 12.5 to around 13.1 or so. I also did a quick WOT blast and saw around 13.2 or 13.3 up top. This obviously came as no surprise since I took away from the overall jetting. Obviously I'll have to jet up the secondaries to bring the WOT AFR back into line.
But here's my question I guess. Am I on the right track? I mean it seems like I still need to go down a few more numbers on the mains maybe down to 70 or so. That would be a total reduction of 6 jet sizes. I would then think I would need to go up that same amount on the secondaries to compinsate.....and that would put me at 92 or so. That just seems like a huge spread in jetting.
I know ultimately, the answer would be to leave the secondary jetting alone and increase the PVCR size, but since that isn't an option for me right now without drilling, can I get there with the jetting? I just don't know how much of a jet spread is acceptable. Any input?
#98
Would running larger high speed air bleeds help this out and keep me from jetting down on the mains? If so, would I only do this on the primary bleeds to keep from leaning out the secondaries?
For what it's worth......with my loose converter, cruise RPMS to me are 3000 to 3500ish.
For what it's worth......with my loose converter, cruise RPMS to me are 3000 to 3500ish.
Last edited by GC99TA; 02-25-2012 at 08:23 PM.
#99
Launching!
iTrader: (1)
Have you read the tuning articles on Innovative's website?
Originally in Chevy High Performance Magazine: http://www.chevyhiperformance.com/te...age/index.html
http://www.innovatemotorsports.com/r...FI_mileage.php
http://www.innovatemotorsports.com/resources/Stan1.php
Originally in Chevy High Performance Magazine: http://www.chevyhiperformance.com/te...age/index.html
http://www.innovatemotorsports.com/r...FI_mileage.php
http://www.innovatemotorsports.com/resources/Stan1.php
#100
Have you read the tuning articles on Innovative's website?
Originally in Chevy High Performance Magazine: http://www.chevyhiperformance.com/te...age/index.html
http://www.innovatemotorsports.com/r...FI_mileage.php
http://www.innovatemotorsports.com/resources/Stan1.php
Originally in Chevy High Performance Magazine: http://www.chevyhiperformance.com/te...age/index.html
http://www.innovatemotorsports.com/r...FI_mileage.php
http://www.innovatemotorsports.com/resources/Stan1.php
So from what I read, I should be able to enlarge the high speed air bleeds to reduce the onset of the mains, as well as lean them out a little when they are active under vacuum. So to me that means they shouldn't be drawing extra air under low to now vacuum (WOT) so that's a good thing. I guess that will give me something to mess with since I have a few blanks........I just need to get some small enough drill bits now.
From I guess I'll enlarge the PVCRs if need be to add a little more fuel at WOT.