xpndbl3

iTrader: (23)

Well little update on the blue beast. Yanked the carb back apart to start playing with all the adjustable bleeds it has in the metering blocks and air bleeds. Went down the idle bleeds so I could turn the mixture screws out more than 1/4 turn, that helped clean up the idle a/f ratio and make the screws less sensitive to adjustments. Then pulled out the power valve channel restrictors and put larger ones in, this will allow me to lean out the primaries for better mpg and still have the same WOT a/f ratio.


Old setup:
1000rpm in gear, 13.8-14.0 at idle
13.4 WOT
12.1 at cruise

New setup
950 in gear(still too high but slowly dialing it in)
upper 14s at idle
12.8 WOT
13.0 at cruise


After getting the cruise into the 14s and then tossing larger PVCR in there again I think it'll really be a nice driving and performing car keeping the WOT in the 12.8-13.0 range along with the better fuel economy out of the primaries alone. Took the car to a car show last night and put 30 miles on her, while getting wideband readings the whole time and screwing with the carb while at the car show. Can't believe how many guys were shocked to see a LS motor under the hood, then all the carb comments as well

team39763

iTrader: (3)

Your car is awesome man. You took 3rd gens to a whole new level.

Ravenous T\A

iTrader: (12)

Hell nobody even Notices mine around here (Tx area)

Pop N Wood

iTrader: (1)

Just curious, why do you have your cruise AFR's so rich? Wouldn't closer to 14.7 be better for MPG?

I'm interested in how you restricted the idle air bleeds to gain some control in the idle mixture screws. Do you remember how much you changed them and what did that gain you as far as the idle screws?

I originally tried a smaller idle feed restrictor, but that did nothing to the idle screws, they were still around I think half a turn. Later I went two sizes smaller on the idle air bleeds and that smoothed out the off idle transition and allowed me to get rid of the 50 cc accel pump. Right now I have to set the idle screws a tad rich to keep from getting a very minor lean hiccup right off idle. They are still near a half turn.

xpndbl3

iTrader: (23)

If you reread what I wrote pop n wood, I stated I need to drop the primary jets more to get a better cruise mixture(in the 14s), but so far it's been a step in the right direction. I think on the idle bleeds it changed by like 12 numbers or something, I just walked into a local speed shop I deal with and the head engine guy said he'll order up what I need. Just popped them in and it made a big change, have to see if I can find the packaging for it or not. I don't have any hiccups at tip in, but I'm also running the 50cc shot on a super victor with 40/40 for squirters front and rear. The motor really wanted a lot of pump shot and even when punching it, I don't get a black cloud of smoke from the pipes like some cars do.

Pop N Wood

iTrader: (1)

Guess you did. Thought maybe you had it that rich for a reason.

Wish I had a well stocked local speed shop. have to get most carb stuff from Summit. I have a base Holley DP with press in bleeds and restrictors. I drilled all that out and replaced them with set screws so if I want to try a different size I need to drill a blank. Probably cheaper that way but wish I had a QF with tuenable everything.

Well if your carb was like mine the bleed change you might allow you to back off on squirters and pump shots and work your way back up again. I was suprised what a difference just two drill sizes made in the transition circuits.

TXoldskool

iTrader: (1)

Sounds similar to my setup. I'm running 2 AEM UEGO's tho for a/f. My 750HP Street carb also needed 40 for the front... tho I have a 37 in the back. My cruise a/f numbers were a little better (usually 13's-14) but mines always been rich on idle.

xpndbl3

iTrader: (23)

Not so much "well stocked" as ask any question in the world and he has an answer to it, then had a machine shop drill out these blanks for me to the proper sizes and I was good to go for under $10

3pedals

iTrader: (3)

my 850 demon is CRAZY rich just off idle, which is where my cruise throttle position is. this is the OEM calibration of the carb, theese carbs were never thought to be going on a 364CI engine and were tuned for more cubes -thats why all the larger carbs seem so rich when you first install them.
I am at 35 shooters on primary, and its close, need a bit more shot. I'll probly end up at 40's like you guys.
I plan to reduce idle feed restricters to clean up the off idle transition, as it is the idle fuel restrictors that have 100% control of the transfer slot.
I have not messed with the PVCR's on this carb yet, just running a 6.5PV in front, and a 8 jet split. I have my WOT A/F at 13.0 :1, it seems happy.
good luck tuning, its a tedious task, but rewarding.

ZONES89RS

iTrader: (25)

I have a quick fuel base and pro form main, stock metering blocks, so mine was a bit easier to dial in, but i still lack the adjustability you have.

xpndbl3

iTrader: (23)

Haven't updated this in a long time. Running 77/93 jets with larger PVCR right now. Just went up 5 numbers on my idle air bleeds to help lean out cruise and went down 4 numbers on high speed air bleeds to help richen up WOT since I've gone rather large on jets and still haven't picked up enough A/F at 6000+ rpm.

idle bleeds 70 to 75
high speed bleeds 32 to 28

Have to wait until spring to see how these changes will work out, but from custom carb builders and dyno operators this is the way to go.

Hopefully be in the 14s soon for part throttle cruise and back to normal sized jets for secondaries, if my idle bleed adjustments doesn't clear up the cruise, I guess the next step is going down .001 in the idle feed restrictors and maybe .002 if needed.

98blueSScamaro

iTrader: (14)

I still need to hear this nasty ride. and she looks killer under the hood steve.

xpndbl3

iTrader: (23)

Thanks Rob, ask chris how it sounded....lol. VERY tame compared to his car, but my win light did come on in our first race lmao. Never mind the fact that I tree'd him then he came wheelie'ing right by me like I was standing still, until he lifted at the 1000' mark and I passed him.


win light steve!! lol

98blueSScamaro

iTrader: (14)

he needs a cage in that car

And i maybe trying a super vic on my pig because my big hog heads only really move air up top.

xpndbl3

iTrader: (23)

Ya he certainly needs a lot of safety equipment in that thing. Definitely should look into that intake on your engine, it woke mine up a lot over the vic jr

98blueSScamaro

iTrader: (14)

also whats your cam specs ????

xpndbl3

iTrader: (23)

smaller than you by far

98blueSScamaro

iTrader: (14)

you were not joking