GC99TA

iTrader: (30)

36/36 high speed and 76/76 idle.

speedtigger

iTrader: (16)

Same here.

Once you get your A/F meter hooked up, let me know how lean you can get it to idle without hesitation.

GC99TA

iTrader: (30)

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.

speedtigger

iTrader: (16)

Your carb should have been shipped from pro systems with 4 blanks.

Sounds about like mine. Every carb they have shipped me has needed to be pig rich at idle to get rid of the lean part throttle and tip in stumble. When I called them about it they had me experiment with the idle air bleeds. It was no help at all.

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.

3pedals

iTrader: (3)

I agree, idle feed restrictions. also what PV you running, too small a PV can cause lean spike when throttle is opened quickly to mid part throttle. old school 2" under idle vacuum is not ideal in my opinion

speedtigger

iTrader: (16)

I tried 4.5, 5.5, 6.5 and 7.5. Same ****.

3pedals

iTrader: (3)

what vacuum does your engine pull at a light cruise? set the pv just below that and try it

speedtigger

iTrader: (16)

Since my Holley HP works perfectly, I am guessing that it is something else.

3pedals

iTrader: (3)

just thowing ideas out for you

GC99TA

iTrader: (30)

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.

speedtigger

iTrader: (16)

Our local tool supply store had them and pin vices to hold them. Try Googling tool supply + your city.

GC99TA

iTrader: (30)

Cool, thanks. I'll check in to it. Will probably have to go to Tucson either way though. Not much in the way of that sort of businesses around here. If you can't get it at Walmart, you can't get it in Sierra Vista.......LOL.

zeosick

Lat eto this thread, but love the car.

GC99TA

iTrader: (30)

Thanks man....there's a link to the whole build thread below in my sig if you want to check it out.

FormulaZR

iTrader: (7)

really, Really, REALLY digging your car man. Nice!

GC99TA

iTrader: (30)

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.

GC99TA

iTrader: (30)

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?

GC99TA

iTrader: (30)

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.

topbrent

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

GC99TA

iTrader: (30)

Thanks for the links. I've already read the second article a few times but had not read the first one (until now ).

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.