It's my 331 that Bryant and I built. Low compression engine 8.7:1, AFR 185 heads, 650dp and hooker headers. My first pull My second pull
I got it dyno'd at JBA. Now I gotta say, I had a very bad experience at JBA the first 2 times I went there. They basically ripped me off, not intentionally but I spent $900 there that I didn't need to. So they gave me 2 free pulls (worth $95) and they were VERY professional about it and when I left they even gave me an apology for the bad experience I had there. But anyways . . .
Whats the timing set up on the engine? My HP guess was kinda off, but the TQ is right where I thought it'd be! What's your HP guess on this engine?
Decent numbers, probly pick up 15 h/p or so getting it leaned out some. The a/f curve is super fat. And needs to be adressed
heres video of mo's car running on the dyno. for some reason its sideways and i cant figure out how to correct the orientation
Nice run Mo. NO problem with the orientation. Gees figured a resourceful guy like you could figure this one out. I stood my monitor on end. Problem solved.
Is the rich A/F due to the jets? I know my primary side is a little rich but the secondary might be also
whats interesting is that at the track I'm still feeling power up to 6800rpm but the torque curve shows otherwise. when should I be shifting according to this?
Look closely at the A/F on the first run. Notice that the A/F is steady at about 11.9 (rich) up til step 66 on the first run then drops to 10.5 (just about ideal) at 68. Then by step 70 you are back at 11.9 and getting more rich as the run progresses. My reading of this is that the jets are a little too large both front and back. Try dropping the Jet sizes down a couple to lean it out a tad. The second run is similar but the lower A/F ratio last longer. Jet change between runs? Doing this may induce a bog as when the throttle went wide open you went lean. This indicates that the accelerator pump may need to either have the size increased or have the stroke lengthened as it's purpose is to prevent that lean condition when you suddenly open the throttle. I would also guess that you would see 10 to 15 f/lbs increase with carb tuning across most of the power band. As for your shift point, conventional wisdom is to shift at or right after peak torque of the motor. That would be ridiculously low rpm with this motor as you have a very flat torque curve. Your torque peak is about 3500 rpm. By 5300 rpm, you are down 50 f/lbs. By 5900rpm, you are down 100 f/lbs. I would recommend making several test runs using 5000, 5250, 5500 as your shift points. Don't change anything else. See what happens. After you add the blower, re-evaluate.
that's a good idea, I'm gonna try shifting in the 5K range and see if my times change. I didn't make any jet changes between the first and second run. I'll change the jet sizes down a little and see what happens. This is fun.
Not arguing your thought process, but you've got it backwards. Low AFR numbers = rich, high numbers = lean.
A good rule of thumb is to shift the car 300 to 500 over peak HP, not torque, I didnt catch if your car is an automatic, if it is, you want a converter that flashes about 200 to 300 over peak torque. my Boss 302 in my Maverick makes 500hp at 8200 rpm, it makes 320lbs of torque at 6100 rpm, I have a Dynamic 7" converter that flashes just shy of 6500, I shift the car at 8000, and go thru at 8500, it will go faster if I shift it at 8600, just dont need to to bracket race it. cars runs mid 10's at 123mph. try shifting your car all over, but I think it will run better closer to 6800 than it will at 5500, also, bump that timing to 36 degrees, then try 38, I used to run my 302 windsor at 40 degrees with race gas in it. Duane
