A/F Ratio tuning questions.....

[61ragtop]

Ok so I have hooked up an autometer wideband to my car and have a question.

At idle I am right at about 14:1 whick I think is good?



At normal acceleration (like driving a daily not like we like to drive, lol) It drops to between 10:1 and 12:1, where should I start to lean this out, primary jets?

I have not had a chance to test out a WOT cause it is to hard to watch the gauge and road as i punch it . But plan to talk my wife into holdin on tight and going for a ride.

FYI It is a 750 speed demon Vac sec carb on a 383ci sbc. Here are my specs....

ENGINE
-383 stroker
-Chevy 350 bored 30 over and stroked to 383ci
-Scat crank 3.75 Stroke Cast 9000 series
-Scat 5.7 forged I beam rods with 7/16 arp cap screws
-Forged Flat top Probe Sportsman Race Series Pistons
-Comp Cams Xtreme Energy™ XR282HR Duration-Intake 230deg Exhaust 236deg @ .050 / Lift Int .510 Exh .520 and 110 lobe separation
-Air Flow Research 195cc Heads 74cc chambers
-9.7:1 compression
-Headman Block Hugger Headers
-Holley 110 gph fuel pump
-Speed Demon 750cfm Carb Vacume secondaries
-Polished Air gap Intake
-Edelbrock aluminium water pump
-MSD Plug Wires
-All Bolts Are ARP
-Edelbrock double roller timing set
-Comp cams roller lifters
-Crane cams energizer roller 1.5 rockers
-Full Mandrel bent Flowmaster American Thunder exhaust With 50 series deltaflow mufflers
-700r4 tranny
-Edge Racing 9" 3200 rpm converter with lock up
-9 inch ford rear end
-Center Section With Motive 3.89 Gears And Auburn Pro series limited slip

And the engine dyno specs....

Intake center line 105 1/2
jets 76 front 85 rear
vac sec spring short yellow
timing 35 deg
RPM----HP---TQ---A/F--Vol Eff%

3900 - 328 - 442 - 13.3 - 97
4000 - 340 - 447 - 14.0 - 97
4100 - 356 - 456 - 14.2 - 97.3
4200 - 370 - 462 - 14.0 - 97.5
4300 - 381 - 465 - 13.9 - 97.5
4400 - 390 - 465 - 13.9 - 97.4
4500 - 397 - 463 - 13.8 - 97.4
4600 - 404 - 461 - 13.7 - 97.2
4700 - 410 - 458 - 13.8 - 97.1
4800 - 416 - 465 - 13.8 - 96.9
4900 - 422 - 452 - 13.8 - 96.7
5000 - 427 - 448 - 13.8 - 96.3
5100 - 430 - 443 - 13.8 - 95.8
5200 - 433 - 437 - 13.9 - 95.2
5300 - 435 - 431 - 13.9 - 94.9
5400 - 436 - 424 - 13.8 - 94.6
5500 - 437 - 418 - 13.9 - 94.3
5600 - 439 - 411 - 14.0 - 94.0
5700 - 440 - 406 - 13.9 - 93.5
5800 - 442 - 400 - 13.9 - 92.8
5900 - 442 - 393 - 14.0 - 92.1
6000 - 440 - 385 - 14.0 - 91.5

I have since upgraded to the New AFR Eliminator 195cc heads due to an issue I had and had them milled to 72cc chambers from 75cc to bump from 9.7 to 10.2:1 compression. They claim the head change with out the compression bump is worth a solid 60 HP and 60 TQ plus 10 HP+TQ with the compression bump. Added to my dyno #'s thats 510 HP and 530TQ it should be putting out now.