Tunnel ram carb tuning
So I finally installed the wide band O2 sensor in my Roadrunner. As expected fat low, lean high. Two Holley 1850-3 with seco daries tied together. I have added Quick Fuel .entering plates on the secondary side so I can change jets. Stock 134-9 which is jetted at 64 according to my QF chart. I have jetted the primaries down to 64 (from 66) with almost no change. I have ordered 60s to try and will modify the PVCR circuit later to jet back up for power. My question is after everything I've read here and elsewhere, I think that I'm going to end up running a much smaller primary jet. I've jetted single quads and can usually see changes in my 02 sensor immediately. Is it because I have 2 carbs now that I seem to need to jet so much? Any experience? See a lot of Edelbrock stuff and double pumper stuff. This is a heavy street car. 68 Roadrunner 440 Mopar aluminum 452 heads 520/540 solid comp. Msd pro billet no vacuum advance. 4 speed 4.10 gears 28 inch 275/60R15 (28 inch) useless tires that just slip through first and second. Car weighs 3970 with me in it. I'm just wondering if it's normal to drop so much jet. Jetting for part throttle cruise A/F ratio. Currently 12.3 to 1 slightly more throttle opening(accelerating not maintaining speed) leans up to 14. Super vaccuum signal. 21 inches @ cruise 15 at idle! Wow. Car runs great but pipes are sooty. Any experience anyone?
So I finally installed the wide band O2 sensor in my Roadrunner. As expected fat low, lean high. Two Holley 1850-3 with seco daries tied together. I have added Quick Fuel .entering plates on the secondary side so I can change jets. Stock 134-9 which is jetted at 64 according to my QF chart. I have jetted the primaries down to 64 (from 66) with almost no change. I have ordered 60s to try and will modify the PVCR circuit later to jet back up for power. My question is after everything I've read here and elsewhere, I think that I'm going to end up running a much smaller primary jet. I've jetted single quads and can usually see changes in my 02 sensor immediately. Is it because I have 2 carbs now that I seem to need to jet so much? Any experience? See a lot of Edelbrock stuff and double pumper stuff. This is a heavy street car. 68 Roadrunner 440 Mopar aluminum 452 heads 520/540 solid comp. Msd pro billet no vacuum advance. 4 speed 4.10 gears 28 inch 275/60R15 (28 inch) useless tires that just slip through first and second. Car weighs 3970 with me in it. I'm just wondering if it's normal to drop so much jet. Jetting for part throttle cruise A/F ratio. Currently 12.3 to 1 slightly more throttle opening(accelerating not maintaining speed) leans up to 14. Super vaccuum signal. 21 inches @ cruise 15 at idle! Wow. Car runs great but pipes are sooty. Any experience anyone?
