wideband installed

kirkallen143":1g5l1fld said:
Howdy,

Started playing with the idle air mix screws, upped the idle to @ 800rpm, now it is idling at 13.7:1 AFR (14.7:1 is optimum)...I can live with that.
Click to expand...

Actually, best idle will be a bit rich, especially at lower speeds. 14.7 AFR is too lean for a good consistent idle. You are right on with 13.7.
 
Doing some research on the holleys and came across the tech section and they say to reference your PV to manifold vacuum for boost applications. You have to drill into the vacuum cavity of the PV on the main body side, jb weld the original hole at the bottom of the cavity, and attach a hose barb and run it to a manifold vacuum source under the throttle blades. A few have done this over at TurboMustangs' forum and had good luck with it. It gives a stronger signal to the PV to help it work correctly under boosted applications (seems to help the part-throttle lean fuel mixture situations). I am getting around to doing this, as soon as work lets up.

Kirk
ps. on vacation next week, I'll get a few things done then
 
Actually, three things:

1) the hole under the carb that goes to the PV is already seeing manifold vacuum

2) they are using modified power valves that stay closed until you hit boost.

3) That mod idn't necessary until you start running rediculous boost levels, like Brent is at 28 psi.
 
Howdy,

Well, I went ahead and re-referenced the PV to a manifold source under the carb body. I just used the original timed/vac port that the metering block already had. What I did was to jb-weld the original source/hole in the PV cavity, and the one in the carb base used for the timed/vac port. Then got out the roto-zip and trenched out @ 1/2"long x 1/8"deep line, in the metering block from the original timed port passage just passed where the edge of PV cavity is. That's done.

Now I am restricting the IFR's (idle feed restrictors) w/ a 0.008" aluminum wire (single strand of 18 gauge speaker wire) and I have drilled and tapped (10-32 UNF) the IAB's (idle air bleeds) for removable bleeds. The stock size of the IFR's are 0.028" on a holley #7448 - 350cfm and the IAB's are 0.070". By restricting the IFR 0.008", I will have to compensate and also restrict the IAB (from 0.070" down to 0.054" (this is just a starting point)). All this, just to try and get better driving characteristics from the turbo engine. Lean at idle/cruise and light load, and then richen up during WOT.

I did try to make it run with only restricting the IFR's and not the IAB's, and it would not idle under 2000 rpm, even with the air/fuel mixture screws out 4 - 5 turns. So that proves it does work. Now once the airbleeds come in, that I ordered, I can get this carb the way it should be...hopefully. Let y'all know more later.

Kirk

ps. the reason I did not just put a wire in the IAB's to restrict them in the first place is because, I did this without my notes I remind you, I thought you had to drill/open up the IAB's while restricting the IFR's...well at least I did have a 10-32 UNF tap on hand.
 
Got everything buttoned up yesterday and tuned in...TALK ABOUT A DIFFERENT ANIMAL!!!!!!!!!!!!!!!!! Good Lord, there is a change in performance b/tw running too rich and then just right. Nice crisp take-offs now, and also when coming out of a corner with low rpms and say in 2nd gear, very smooth transition, no bogging or hesitation.

I did re-reference the vacuum source to the PV as you all know and now no more lean spike just off the throttle, YES! It idles at @ 12.5 :1 AFR, cruises at @ 14:1 AFR and WOT is at @ 10.5 : 1 AFR(still on the rich side, 11.5 to 12 :1 is ideal). I restricted the IFR's down w/ 0.016" wire and then went down only to 0.059" on the IAB's (could use a little more though, only 3/4 of a turn out on the idle mixture screws) I think I need to be out more turns with the idle mixture screws, because when coasting or slowing down from highway speed w/ foot off the throttle the gauge reads lean (up to 16.5 - 17 : 1 AFR). With more fuel in the idle circuit this just might solve the lean issue. I will go with the 0.049" air bleeds next and let you know. Have a good one

Kirk
 
kirkallen143":2jb08gd7 said:
I think I need to be out more turns with the idle mixture screws, because when coasting or slowing down from highway speed w/ foot off the throttle the gauge reads lean (up to 16.5 - 17 : 1 AFR).
Click to expand...

NO!! Don't mess with it, its supposed to do that!

Lean condition on deceleration is 100% normal!

Just worry about the mixture when accelerating,
deceleration has nothing to do with anything.
 
hmm maybe I need to get that wideband off my buddy and get my holley dialed in better. so kirk you said you had a lean spot at part throttle? I am feeling like I have one there on my current tune. it will pull fine under boost but if you give enough throttle to accelerate but out of boost it feels lean (surges a little and weak, no bog though as if it was rich) after driving my car this weekend I think I really need to push for the EFI on it.
 
Had alittle time yesterday to mess with the bronco, tried the #57 jets-- idle was OK, not enough fuel at part throttle and cruise (reading @ 16:1 AFR on gauge) and would not start without hitting the accelerator. Then went up to #59 jets better quality idle w/ mixture screws out 1 1/4 turns, reading mid 13's on the AFR gauge, but still cruise was running in the 15's on the wideband. So I just put the #60 jets back in, w/ a 6.5 PV, and restricted the pvcr's (currently drilled to 0.080") with @ 0.024" aluminum wire, and now my WOT is up around into the 11's on the gauge, and cruise is in the 14:1 (+/-) area. I also put the 0.028" squirter back in and it seems to help cover up some of the off-idle bog/hesitation I have when easing into the throttle.
Now all it wants to do is break the back tires loose, so it must be running purty good.

Kirk
 
Good morning,

Well last night after my four kids were asleep, took the bronco for a couple of WOT runs. AFR is right at 10.2:1. What would be a better approach to get this # up to @ 11.5:1?
I have the pvcr's drilled to 0.080", then restricted them with three 0.008"aluminum wires twisted togethter, should I add more? Jetting is right on and does not like either direction I go. What do y'all think, restrict the pvcr's more, huh.

Kirk
ps. the acceleration from this turbo made me feel like I was in my old '77 Z-28 w/ 350hp, now that was a ride. The hard part is trying to keep this bronco out of the ditches.
 
Does10s":19cqsad0 said:
Ya Kirk, 10.2:1 is a bit fat! Need to shoot for around 12:1.
Will
Click to expand...

I wouldn't go as lean as 12:1. That would be great if it was NA, but boosted should be a little richer.
 
Linc's 200":3d634m71 said:
Does10s":3d634m71 said:
Ya Kirk, 10.2:1 is a bit fat! Need to shoot for around 12:1.
Will
Click to expand...

I wouldn't go as lean as 12:1. That would be great if it was NA, but boosted should be a little richer.
Click to expand...

Yes Sir, I was looking for nothing above 11.5:1 AFR at WOT. This 200 doesn't like running lean at all, he misses a beat every once in a while, if you know what I mean.

Well, off to buy some bigger brass and/or aluminum rod.

Kirk
 
Well, I turned the boost up on the bronco yesterday (one full turn of the internal wastegate actuator arm from the diaphram) and I can tell you this engine combo did not like it. Sounded like a bunch of little tiny hammers inside the block, the vacuum gauge was reading funny, and way lean on the AFR at WOT. I just did it to see what it would do...and then I turned the boost back down.

First, I should of retarded the timing down to 20* to 22* total from 27* total, richened up the mixture (jetted it up) and then I think I would have been able to handle the more psi.

Actually, I like the 10 psi I am at now, with the bigger boost the psi came in too fast and made the bronco's manners less driveable. It was fun though, like all it wanted to do was haul a$$, it was hammer down or nothing at all. Now I know where to set it when it is time for another sand-drag race. God, I love this turbo stuff.

Kirk
 
that is why I love the early 2.3L turbo'd cars with the T3's on them. set at the factory 8psi the t3 is doggy.....crankit up into the "sweet spot" and they nearly double their power!!

I can see a turbo being fun on sand drags....power comes up as you gain traction and get moving..

PS I want to see some turbo muddin action!!!
 
You must log in or register to reply here.
Back
Top