Interesting. I know this is a lean pop because I can see it on the WB02 gauge itself, as well as the logs. I have wondered if I don't have enough timing now though.
Well what I was saying is that increasing the Delta TPS and MAP AE seems to help lessen the lean pop when you smash the throttle open quickly, however, those same changes appear to have made it overly rich on very light throttle tip in pulling away from a stop. It literally pegs my WB on 10 AFR for a second or two. I've read several threads on TGO where Dewey talked about having a similar/same issue... Here's one I stumbled on
https://www.thirdgen.org/forums/tbi/...ifold-big.html
Where is this max PW you speak of? Do you think the 350 AE parameters would be closer??? I thought with the big throttle body and single plane carb intake it would be closer, but now that you mention the 454 manifold was smaller.......
I was running the stock L05 timing table from the $0E bin I started with. I then copied over the timing table from Brian, (sturgillbd on here). His timing table IIRC has a little more advance in it. It seemed to help mine with the lean pop when you smash the throttle open....
I'm running TrickFlow aluminum heads https://www.summitracing.com/parts/SUM-162108
Maybe with these new heads and the single plane, flat top pistons and everything else I don't have near enough timing advance for this combo? Anyone have a timing table for such a combo that might be closer in the ball park vs what I've tried?
Initial spark advance is 3*
Last edited by CDeeZ; 03-02-2019 at 10:22 PM.
Homemade injector flow bench: https://www.youtube.com/watch?v=e_g9K0VEsfE
http://www.youtube.com/watch?v=zBYMtJO0pX8
I have the same heads and a 46mm TB with 18LB spring on a 3704 intake (bored out to 48mm).
AMUS 2.JPG
How's yours running? My TB measures nearly 52 MM... One of the reasons I suspect AE is what is causing this lean pop.
Homemade injector flow bench: https://www.youtube.com/watch?v=e_g9K0VEsfE
http://www.youtube.com/watch?v=zBYMtJO0pX8
It's getting better, Dave helped me get the Main Fuel table dialed in so my BLM is ~127 ave. Now i'm adjusting VE and PE with data logging. Of course mine's an '88 with 7747 and I'm guessing my cam (207/213 @.050, .466/.484 with 1.6 rockers) is milder than yours. Here's where I am so far;How's yours running? My TB measures nearly 52 MM... One of the reasons I suspect AE is what is causing this lean pop.
PE-AE bin 06.JPG
The first 25% of throttle angle change makes a greater difference in air density than the next 50%. I tend to ramp MAP AE in faster than TPS on a larger plenum. Then I'll increase the MAP difference to enable AE as a limit to MAP contribution at low throttle angles. This helps prevent rich surges when load changes without much change in throttle.Well what I was saying is that increasing the Delta TPS and MAP AE seems to help lessen the lean pop when you smash the throttle open quickly, however, those same changes appear to have made it overly rich on very light throttle tip in pulling away from a stop.
Are those heads a fast burn style? They might require a fair amount more timing.
Thanks 1p2m, Good info! These heads (SUM-106108) have 170cc intake runners, from what I understand "fast burn" heads are 210cc which come into power at higher revs. Although these heads have bigger valves (2.02/1.60 compared to ~2.00/1.55) I'm wondering if they are a good match for a single plane manifold with a 7.4 TB on a SBC???The first 25% of throttle angle change makes a greater difference in air density than the next 50%. I tend to ramp MAP AE in faster than TPS on a larger plenum. Then I'll increase the MAP difference to enable AE as a limit to MAP contribution at low throttle angles. This helps prevent rich surges when load changes without much change in throttle.
Are those heads a fast burn style? They might require a fair amount more timing.
CDeeZ: do you have a 5.7 or is it stroked? A 350 @ 6,000RPM only needs a little over 600CFM (check out the "Carburetor Sizing" at the bottom")
http://www.tciauto.com/tc/racing-calculators
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