"Cough" when the Secondaries open :(

Discussion in 'Holley' started by sriley531, Sep 21, 2015.

  1. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

  2. sriley531

    sriley531 Buckle up, this could get rough....

    Added to wish list for safe keeping Larry, thank you. Looks like I'll be ordering a few of those up!
     
  3. sriley531

    sriley531 Buckle up, this could get rough....

    After much consideration, I decided with all the money I have invested in this car (in this case the engine specifically) its penny wise and pound foolish to be tuning by butt dyno a fume plume. So before I go any further, I ordered an afr gauge setup this morning, should be in next week. Going to get it put in and try to get a decent tune in the car before its time to take its winters nap.
     
  4. jzuelly1

    jzuelly1 Jesse Zuelly IV

    Smart thinking sir. It still runs and drives and makes you grin from ear to ear right? The piddly stuff can be sorted out over time.
     
  5. sriley531

    sriley531 Buckle up, this could get rough....

    Yep, still fires up and runs like a champ. Casual cruising you'd never know I was chasing the tune on it, and even under wot once you get past the cough (just ask the kid in the mercedes I crossed paths with recently :TU:). It was just the fact, the more I thought about it, why go through the trouble of things like ported aluminum heads etc and leave power on the table with a carb thats not quite dialed in. I know reading plugs works, but I love real-time data. So I felt it was just a piece to the performance puzzle and just another drop in the bucket.






    And it may just come in extra handy IF a certain type of ominous bottle were to ever appear in the trunk... :Do No: :3gears: :Brow:
     
  6. DEADMANSCURVE

    DEADMANSCURVE my first word : truck

    so when ya puttin' the dyno in shawn ?
    and just thinkin - next time ya have the bowls off to check jets or whatever - check the gasket between the bowl n metering block for off center or restricted gasket opening for the pump shot passage way . probably not but easy to check . seen a couple i wasn't happy with .
     
  7. sriley531

    sriley531 Buckle up, this could get rough....

    I finally got off my butt and got the afr gauge installed. Hopefully I can get back to tuning this week. Thanks again for all the great input, stay tuned!!! (I'm not done leaning on you guys yet!)

    [​IMG]
     
  8. sriley531

    sriley531 Buckle up, this could get rough....

    Ok gents, I cleaned up my wiring mess, fixed a coolant leak (lose lower hose clamp, SMH...) And went for a quick blast around the block (my "block" is about 5 miles) and got some numbers. Hot idle (not that it matters much) is high 11's low 12's, cruising (again not all that important) was mid 12's and WOT in 4th was high 12's low 13's. (Man, on country roads that thing is hard to watch and keep am eye on the road with that car floored in 4th!) Oddly enough wot in 3rd was mid 13's (maybe cause the revvs climb faster??) Not surprisingly, the "cough" makes it go crazy lean for a split second (15's and 16's). I've got 5.5 power valves to put in, but I think I'm also going to go up another squirter size in the rear. I'm considering dropping a couple jets sizes all around since its slightly fat across the board. Thoughts?
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I think your WOT is pretty good at high 12's low 13's. If you drop jet sizes, you will lean that, not good. You are fat everywhere else though. I'm no Holley expert, but if you want to make that into a carburetor that is good at the track and on the street, you might have to lean the jetting and open up the power valve channel restrictions, so that when the power valve opens, it adds more fuel.

    When I was at Cecil, I looked at my A/F in high gear wide open, with the AED1000, and it was 11.9. Of course the air was terrible (DA of 2800'), but I dropped it 2 jet sizes in the front only. My trap speed went up .5 MPH, and it was still at 12.2.

    My Q-jet read 13.0 at WOT in high gear at the track. On the street, hot idle is mid 13's, and cruise is high 14's to low 15's.
     
  10. sailbrd

    sailbrd Well-Known Member

    Hot idle should be 13.5 to 14. You can try going bigger on the idle bleeds. If that does not help go smaller on the idle feed restrictors. Need to get to this step before working on cruise.

    Cruising: You should be able to cruise at around 13.5. See what your AFR's are at constant 1500 rpms in 2nd, 3rd, and 4th. You should be able to be about the same as at idle. Then as you go up in rpm see where the AFR's go fat. When working on cruise you might want to put in a high vac power valve like a 9.5.

    Go ahead and add more pump, you now know you are lean.

    Larry is correct that going up on the PVRC's is a good way to add fuel to WOT.
     
  11. Skippy597

    Skippy597 Silver Level contributor

    Did you ever get this sorted out?
     
  12. sriley531

    sriley531 Buckle up, this could get rough....

    Wow, I forgot all about this thread! Yeah, I got it straightened out. It's been so long, I don't remember the exact combo of jets/squirters/power valves/cams that did it (I have the entire evolution written down somewhere), but anyway it cruises at mid 13's AFR and doesn't have the hesitation anymore.
     
  13. Skippy597

    Skippy597 Silver Level contributor

    Well good to hear! If you ever tear into your carb again please update this thread with the size of jets, PV, and squirters you settled on.

    Ryan
     
  14. sriley531

    sriley531 Buckle up, this could get rough....

    I'll see if I can find my little notepad where I tracked changes and the results of each change.
     
    Skippy597 likes this.
  15. sriley531

    sriley531 Buckle up, this could get rough....

    Been crazy busy, haven't gotten a chance to get out to the pole barn and see if it's where I think it is. I'll try to get out there this weekend.
     

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