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5 minute(s) of a 70 minute read
9-7-2008
I went with the advanced street settings and this is what they came up with. The guy at SEARS told me that I didn't do half bad eye-balling the suspension when I put it all back together........made me feel good! I'm no expert on it either but I think I'm close with what I have. I'll need Brian to chime in on this one because I know he's pretty heavy when it comes to the suspension settings on our cars!
9-10-2008
This is what WE came up with here at work...........seeing how we had a demo last night on 3rd shift and had a surplus of Engineers (ME's and EE's sitting around being bored), we decided to just try and solve this mystery. I agree with the formula never doubted it or questioned it and yes RPM and Torque always cross 5252rpm.
I saw 388hp @ 407tq which was very close to 5800rpm before I left on Friday but is the start of my confusion.
388hp=407tq*(5800/5252) assuming the dyno went to 5800, and doing the math the numbers don't work out. If I assume that the RPM and torque are correct, then the calculated hp is 449.46 rwhp. This is well above the 421 that Ed saw and leads me down the path that the 421rwhp must be at 5500rpm. IF, i compare my 5800 rpm calculation for the 449, then I'm Dead ON with Chad's chart............If not, then it doesn't come close.
This data point was confusing but once I started making overlay comparison's to his dyno chart, THEN things started to make sense. So, here's Chad's chart (Hope you don't mind Chad). I'm using Chad's dyno because the motors are similar, but Chad has alot more compression and a much more aggressive cam that I. My heads should flow better on the upper end and make my peak power slightly higher than his motor. Chad's motor make Power lower than mine, while my torque curve goes up and is straight as a board across the entire scale. IMHO both motors are spec'd out very close to the same bottom line number, it's just that they take different routes in order to make their respective power!
I'll see if this REALLY clears the confusion that I was suffering before!
388hp=407tq*(5800/5252) Doesn't work with the assumed 5800 rpm.
This HP and TQ work if the RPM is 5006: (388/407)*5252=5006
And when I compare the 5006 data point on Chad's chart, I'm so close that it HURTS! This also makes sense as to where the dyno was only reading up to ~5000.
If I calculate with torque and RPM being a known value then (407*1.104)=449hp.
449hp=407tq*(5800/5252) This is dead on when compared to Chad's dyno sheet, so it does pass the sanity check.
Ed said that he was able to rev up to 7000 with a few hiccups, but only got a good spin to 5500. If he took and figured out the HP based upon RPM then he saw 421rwhp. IF, This 421rwhp was based off of 5500rpm then EVERYTHING makes sense to me. IF It was 421 extrapolated from a 7000rpm, then I'm lost.........SO we will assume that the 421rpm was based up 5500rpm as seen by Ed, which means that:
421=y*(5500/5252) which is: 421=y*(1.047) and: 421/1.047=402
So at 5500rpm the motor is making 421rwhp @ 402ft/lbs of torque. If this is taken to Chad's chart for reference, it ALSO lines up dead on and could work.
I then calculated a ROUGH, VERY ROUGH estimate of 513chp @ 496ft/tq.
The problem with that 513/496 calc is that it is only at 5500rpm, my peak isn't until 6300rpm. SO, we played with some numbers on the curve using Chad's chart as a template and we came up with 549.XX chp @ 6300. I'm not sure HOW accurate that is, but after using the Math to calculate what I had and making the assumption that Ed's reference was at 5500rpm, then it works. IF Ed's reference is at 7000rpm, then I'm back at square one lost and confused. I also understand tht my hp/tq curves will be slightly different, especially in the upper spectrum but this was a S.W.A.G. for reference. That's what I got and I'll wait to see if there's anything that I missed, or calculated/assumed wrong.
Now that I've had my Math drill for the day, I need to see if the hiccup is my Motor, or the dyno. If it's just a loss of sync or signal to the dyno, then that's not a HUGE deal. If my motor is loosing firing signals, then "HOUSTON, WE HAVE A PROBLEM!"
just tried to calc the 385hp @ 5800 and that is even more inconsistant with Friday. Now I'm WAY confused with what's going on. The torque curve that I saw was flat as a pancake all the way across, and to get to 385 at 5800 tells me that the motor, although hasn't reached it's peak band has started to LOOSE power?.............Unless the pulls on Friday are completely invalid, then 385 would work, but now it's getting worse.
Also, where is the hiccup? my car of the dyno interface with my c