Post by montess383 on Aug 30, 2011 10:40:35 GMT -5
hello im new here, found this site on a google search earlier. there seems to be very smart people here, i just recently put the quickfuel e85 metering blocks on my holley 750 HP series carb, everything else on the carb is stock, ive got a few problems, all 4 idle mixture screws are only about 3/4 of a turn out and it idles around 11.5 to 12 afr, if you turn the mixture screws in to get it any leaner at idle it will die out when coming to a stop. also when you get on it from a dead stop it will hesitate, and sometimes hesitate so much it dies, but if your already rolling at like 45mph it will hesitate some and then take off breaking the tires loose. heres what the carb has: primary squirter- 28 secondary squirter- 31 primary high speed air bleeds- 71 primary idle air bleeds- 25 secondary high speed air bleeds- 28 secondary idle air bleeds- 36 primary jets- 73 secondary jets- 82 power valve- stock dont remember the size. pink accelerator cams.
whats obvious that i should change to get this thing to run better and then fine tune from there? also what readings should i be looking for with e85 on my inovate wideband for idle, cruise, and wide open throttle? some people have said tune it for the same readings as gas and others have said things completely different. i would really hate to put the gas metering blocks back on and run gas...
car specs: chevy 383, 10:1, world product sportsman II heads, air gap intake, cam: 233 int./241 exh. at .050, engine pulls 9in of vaccum at idle, 3000 stall and 3.73 gears.
the air bleeds are backwards in your head or in carb . high speeds air bleeds are small in 25-35 range and idleair bleeds are in 60-70's , ifr and pvcr in m blocks can vary widely due to combo . if the boosters and channels are spot on to carb size vs cubic inch you can get away with 35-40 shooters, hollow screws and small pumps and reg cams .most use 40+ and one 50cc pump . .
jets are way lean . should start 10 over best gas pass numbers on 85% and work down to best mph .did you test fuel??? 70% will want 1 step leaner air bleeds and 3-4 jets less .the h/p carb was a funtional 4 corner idle but some throttle base were not blocked front to back ...is your?
Post by montess383 on Sept 10, 2011 20:09:24 GMT -5
i have not tested fuel yet, i just ordered a tester the other day. i had the air bleeds backwards in my head, i got my air bleed kit the other day and put 63 in the IAB and 28 in the HSAB. i also put 45 squirters in it and moved the primary jets up to 80 and the secondarys to 89. and the power vavle is 6.5 high flow, the hesitation off idle is gone, how ever it still runs very rich, like mid 10s to low 11's at cruise, and high 11's to low 12s at idle, how do i check if my base plate is blocked? this is my first 4 corner idle carb ive ever had. all 4 of the idle screws are only half of a turn out. do i need to go bigger or smaller on the IABs to fix this? or do i need to put restrictions in the idle circuits on the metering blocks?
Post by adamsandriod on Sept 11, 2011 6:14:06 GMT -5
If you large up the iab you wil need more idle screw out ro comppensateand you will lean on the fuel going to transferslot and your part throttle cruise and tip in. Are you using the o2 scale on a e85 calibration . Use lambda as it is unversal and no water what fuel you got the mix shoould 1.0 idle and 8.0+- at wide open .for intense and porpose your cruise afr with a proper timing curve can be way lean . Ease test to se what it wants is to block off power valve and add 8-10 jet .as long as your data is goood you should be way fat .each combo is difffernt. If the iabs get you about 1+ turns and cruise and accel are good we dont need any more mods. We have tslot size and power channel restictors to get more. Is timing locked or curve? This will effect afr and throttle responce too.
Post by adamsvega on Sept 11, 2011 13:02:00 GMT -5
SOUNDS LIKE THE PLAN GO TO 65 AND SEE HOW IDLE SCREWS RESPOND AND IF TIP IN HESTATION OR LEAN CRUISE IS PREASANT ..... I WOULD THEN TRY TO FATTEN UP PRIME JETS TILL ITS BETTER AND IF IT HAPPY DOWN LOW WE CAN TAKE AWAY FUEL FROM POWER VALVE RESTICTION TO GET TOP END W/OPEN MIX BACK ON TRACK
Post by adamsvega on Sept 11, 2011 13:13:58 GMT -5
DOES YOU METER HAVE CALIBRATION TO FUEL AND % OF ETHANOL. IF NOT ALWAYS USE LAMBDA FROM NOW ON OR DATA IS WORTHLESS AS % CHANGES . TALKING WITH SOME OF MY TUNER FRIENDS THEY SETTING UP CARBS TO RUN ON 85 % IN WORST AIR SO CUSTOMERS WONT HAVE BUT 1 JET FOR 79% AND 1 FOR 70% AS THE AIR GETS BETTER AND IT WANTS FUEL IT WILL BE SAFE IF THEY DONT CHANGE AND FASTER IF THEY DO .ITS THE GUYS THAT RACE ALL OVER WITH DIFFRENT DENSITY ALTITUDE AND FUEL SUPPIERS THAT WILL NEED TO KEEP TRACK AS THE TUNE MOVES ....BUT THEY ARE USED TO THAT AROUND HERE I CAN GO FROM 4500 FT TO -600 IN TRACKS AND SEASON I RUN AND DRY TO SATURATED AIR .
my meter always displays lambda and AFR at the same time, i just have the tendancy to always look at the afr instead for some reason. i have an air gap intake, im not quite sure if my air cleaner will even fit under the hood i havnt even tried it yet. but if its the same height has the performer rpm it should have about half an inch to spare with the air cleaner on.
i just went and changed the IAB to 65 and the afr went up to around 12.8 to 13.1, lambda is between .86 and .89, i didn not adjust the idle mixute screws. there is no hesitation with the car in park, however i did not drive it because im not in the mood to pull 4 other cars out of the driveway so that will have to wait for tomorrow
Last Edit: Sept 11, 2011 20:23:46 GMT -5 by montess383
im getting that fixed at my house with a 10 ft gate at back end of driveway. ( thanks yellow bullet $$$.) just open and drop . you can just use the gas afr number and tune it like gas . be warry any misfire that does not use up the oxygen pulled in on intakes will show up as lean spikes on data on a guage way fat will boble around but read right and way lean will just be down on power and only read slighly lean .