G
Guest
·Short story: WAY WAY WAY RICH
Short story: WAY WAY WAY RICH throughout the whole range.
Took the car for its first dyno run today as I tweak the carb settings. I succeeded all too well in avoiding a lean situation (no wonder it starts so great on snowy mornings).
During the entire run the A/F was usually well below 12, peaking at 12 at 6000, then falling off to 10 at 7000. Did not get a downloaded graph, but the curve was very smooth (4th gear used). The curve leveled off at 6000 rpm and held close to peak hp through 7, only dropping a little. I think I can find a few more ponies leaning out the mixture, as well as going to a 36mm venturi for more flow.
Carb: Weber 40 DCNF; 34mm venturi; 150 mains; 190 air correction; .6 idle; stock FI cams
Dynojet
rpm-----rwhp(SAE)-----torque-----A/F
4.0.........137................180.........10.0
4.5.........158................184.........10.0
5.0.........181................197.........10.7
6.0.........220................193.........11.9
6.5.........224................181.........11.5
7.0.........214................161.........10.1
7.5.........212................149.........10.0
With the 17% fudge puts me at 260 hp SAE (270 DIN) with suboptimally rich mixture and before any tweaking. I'm told that peak hp occurs around 12.5 to 13.5 A/F, so have a lot of room to improve. Sure explains the sooty tailpipes.
Current plan:
More air, less gas
upsizing the venturis to 36mm for more flow, keep 150 jets in for first run, but have a set of 145 mains ready. Probably should have some 200 A/C as well. This jetting stuff is pretty cheap.
Once I get the new distributor on will roll in a bit of advance as well.
Cams probably at the first part of the year or so.
Considering these first settings were a WAG on my amateur part, I'm pretty proud it runs at all. If I can get the mixture better with more flow, will have much improved response and peak hp. The response and drivability is already way ahead of the FI.
As a side story, the dyno tech at this Mustang hot rodding place says it was an extremely smooth pull and a very smooth and flexible engine - and these numbers are about what he sees from a stock 5.0 liter mustang.
Will be ordering the new jetting tomorrow. Damn, this is fun.
All advice welcome, and thanks to all the great help from jrv, David and many others over the past months.
best to all
rt
Short story: WAY WAY WAY RICH throughout the whole range.
Took the car for its first dyno run today as I tweak the carb settings. I succeeded all too well in avoiding a lean situation (no wonder it starts so great on snowy mornings).
During the entire run the A/F was usually well below 12, peaking at 12 at 6000, then falling off to 10 at 7000. Did not get a downloaded graph, but the curve was very smooth (4th gear used). The curve leveled off at 6000 rpm and held close to peak hp through 7, only dropping a little. I think I can find a few more ponies leaning out the mixture, as well as going to a 36mm venturi for more flow.
Carb: Weber 40 DCNF; 34mm venturi; 150 mains; 190 air correction; .6 idle; stock FI cams
Dynojet
rpm-----rwhp(SAE)-----torque-----A/F
4.0.........137................180.........10.0
4.5.........158................184.........10.0
5.0.........181................197.........10.7
6.0.........220................193.........11.9
6.5.........224................181.........11.5
7.0.........214................161.........10.1
7.5.........212................149.........10.0
With the 17% fudge puts me at 260 hp SAE (270 DIN) with suboptimally rich mixture and before any tweaking. I'm told that peak hp occurs around 12.5 to 13.5 A/F, so have a lot of room to improve. Sure explains the sooty tailpipes.
Current plan:
More air, less gas
upsizing the venturis to 36mm for more flow, keep 150 jets in for first run, but have a set of 145 mains ready. Probably should have some 200 A/C as well. This jetting stuff is pretty cheap.
Once I get the new distributor on will roll in a bit of advance as well.
Cams probably at the first part of the year or so.
Considering these first settings were a WAG on my amateur part, I'm pretty proud it runs at all. If I can get the mixture better with more flow, will have much improved response and peak hp. The response and drivability is already way ahead of the FI.
As a side story, the dyno tech at this Mustang hot rodding place says it was an extremely smooth pull and a very smooth and flexible engine - and these numbers are about what he sees from a stock 5.0 liter mustang.
Will be ordering the new jetting tomorrow. Damn, this is fun.
All advice welcome, and thanks to all the great help from jrv, David and many others over the past months.
best to all
rt