I am pretty happy with these numbers since I am running ported #241 heads and a Torquer II cam on a big 408. Could that smallish-compared-to-my-cubes cam be the reason for the big torque drop off starting at 5000rpm?

Would moving to the likes of a TSP giant up my power closer to the 500 mark? I have almost talked myself into a bigger cam. Any advice?

** check out the running conditions: temperature!

dyno.gif

 

Good graph, it is a rather small cam in a 408 (like a 220 in 346), awsome trq if you ask me. You could retard the cam a little to make it spin farther (shift the curve a bit higher in rpm)

 

Thanks, I thought of that as well. My goal was to lay the smack down on this pesky '03 Cobra running a ported blower and Meth injection. I can hang beside him now through 4 gears. I guess I should be happy with that since I am running 0 lbs of boost. If I put in a bigger cam and get another 25-30 lbs of torque, I think I can pull him. Isn't it funny what things drive us to spend money

 

Do you have a plot of the air/fuel curve? It looks to me like you may be a bit lean @ 4,400 RPM to 4,600 RPM & then a gain @ 5,500 RPM through 6,400 RPM, based on the shape of the torque curve. If this is the case, there's a bit more power under the curve & @ the end of the run.

 

I don't have that, but from my memory, it seemed to be pegged at about 13:1 across the range after 4000. I looked at my dyno from my 346 - before the 408 build. See it here.

The 346 used the exact same heads and cam I have now in the 408. Seems that the entire curve on the 408 is shifted back 1000RPM. Maybe the larger cubes simply means all the power is lower in the band. I would love to know how the motor would perform with a TSP giant. I also wonder if my ported #241's can keep up. If I can make ~500/500 with stock heads - that would be sweet!

Thanks

 

To me, that air/ fuel is lean acroos the board. It's real lean up to 4,700 RPM & a bit lean after. Before 4,700 RPM it is lean enough that the knock sensors could be pulling timing, which expalins the early dip in torque. The lowest air/fule ratio I see is 13.2. If it were my car, would have the car re-tuned for no more than 13.0 up to 4,500 RPM & 12.9 there after.

As for a different cam, don't know for sure. First I would fix the fueling.

 

it's not the cam, get rid of the pos 241 heads...there are such better alternatives to P&P 241s.

 

I disagree with the above. If youre already running ported heads, I think youll see bigger gains by stepping up to a larger cam in that 408. Certainly the heads will help, but I think the cam is holding you back more than the heads, although it really is impossible to tell without more info.

 

Thanks for all the great info. Mainly, the budget is keeping me from going with bigger heads. Sure, I'd love to have a $2500 set of AFR's but no $ means no GO.

Besides, if I can make 500/500'ish with a set of stock ported heads, I might start a new trend. The home-ported-500RWHP-heads. I'd be happy with those numbers for sure. Has anyone else done it? With the right cam, I can see 500 out of these heads. That's bound to make someone question the reasoning of putting a $2500 set of heads on a 346.

13:1 is too lean? I have HP tuners, what do I need to do to get that richer? Is it the commanded A/F I need to change? Any help there would be great.

 

I'm no expert, but to answer your original Q, the TQ curve looks awesome to me. And your results, given your combo, are excellent. Your power curve/peak looks like a bigger cam would indeed help. Not as much as a set of top shelf heads, but a lot more bang for the buck.

 

I see 14:1 down to 13.8:1 up to 4,000 RPM & dropping to 13.4:1 up to 4,500 RPM. The early dip in torque could be engine knock causing the knock sensors to pull timing. Further, I see 13.2:1 through the remaining RPM range. Looks to me like HP is drooping for the laste 6 or 700 RPM. You may see more hp by getting the A/F flat from the start of the wide open throttle pull to the end & error to the side of 12.9:1 above 4,500 RPM. This should also get rid of early dip in torque. Of course this is only my opinion. I would never allow my car to be set up w/ greater than a 13.0:1 A/F ratio above 3,400 to 3,500 RPM @ WOT.

Sorry, can't comment on the HP tuner question. Try posting your dyno showing the A/F w/ your question in the tuning section. Lots of good guys in there. Good-luck.

 

Ideally, I hear it's good to shoot for a mid-12 AFR at peak torque and lean out to a high 12 at peak power. If you have HPTuners, you can change your WOT AFR in the PE vs RPM table. Changes should be based on good, reliable data (i.e. a WBO2) - not bad/inconsistent data (i.e. the factory NBO2's).

 

Thanks everyone. I'll work on getting me a WBO2 ASAP. I needed to do that anyway.