Of course comparing dyno numbers will only get you so far, and I suppose in many cases do nothing but get you into trouble, but nonetheless I have a question.
Please follow my logic here.
My car has been dyno'd many times over the years. I have kept the dyno charts and notes of what mods the car had at each dyno session. I have done this for my own purposes only but it comes in useful from time to time when attempting to understand things.
I dyno'd my car with some heads that had minor port work done to them. No welding, no enlargement of the ports etc. and no flow bench work. Just a basic port job done by a shop that had never even seen 3.8L Ford heads before. At this time I also installed the cam that is still in the car today, and I installed a home-made FMIC and stock S-Port blower with NO OVERDRIVE. I used the stock blower pulley. In this form the car made about 12psi and made 313rwhp adn 363rwtq on the dyno. This is the car that is represented in the chart below as
XR7 1.
Then later I replaced those heads with some "fancy" Steigemeier heads, I added the MP inlet plenum, and I increased blower drive ratio by 10%. In this configuration the blower generated about 15psi and it made 344rwhp and 402rwtq. The dyno chart was posted at the front of this thread and is represented here by
XR7 2.
This car is and was one of the fastest cars known to this club. It's not THE fastest by any means but most everyone here has seen this car run and knows how it runs. My only point in saying this is that this car, with 400ftlbs torque and 344rwhp ran a whole string of 12.60-12.80's @ 108-109mph. The car's performance is well documented.
Now then the car tested by Fast Specialties and used to promote the MPIII is in fact very similar to my car. It is a 5spd. It has the advantage of any and all available bolt on parts to enhance performance, and it has ported heads and cam upgrade. This car made 390rwhp and 469rwtq at 17psi. It is represented on the chart as
FAST XR7.
Now it has been said that my car has fancy heads that are giving it extra performance at high rpm. I disagree with some as to the real impact of this. If you look at the chart you can see that with the non-fancy heads on the car, torque output at higher rpm pretty much mirrors that of the motor with the added boost from additional OD and a better flowing intake. If the Steig heads really made a big difference I would have expected to see gains in the upper rpm moreso than the lower ones. Instead I see bigger gains down low than up high which is indicative of the blower running out of air as noted in the preceding posts. Nonetheless, the better flowing heads are probably having some impact, but it certainly isn't discernable from the charts.
Maybe you agree with this, maybe you don't. But lets move on.
I do know one thing about the Fast Specialties car.
Our cams are identical. 210/220 dur. and .491" lift (.513 with 1.8rr). I did also in fact verify output before and after installation of the 1.8rr's on my car and documented on the dyno that there was no increase in power. Just so you know.
So. With very similar cars and the same cam, my question is, how did the Fast Specialties car manage to make roughly 70rwtq more than my car did at peak torque rpm, but only 35rwtq more at peak HP rpm? Why did the torque advantage drop by a full 50% by the end of the rpm range? I thought the MPIII was a high rpm race blower? Why is it losing tq so rapidly at high rpm?
Look at the chart. Tell me why this is. Because it bothers me that this dyno chart shows frankly very weak high rpm performance yet completely gangbusters torque at lower rpms. And if in fact this is typical of the MPIII's performance characteristics, then why did we not see a similar trend on Dan Sly's car? Surely if there was belt slip on Dan's car at 3000rpm it must be getting worse as rpm increased, no? If it was getting worse or even staying the same, then why did Dan's car outperform mine in the higher rpm ranges while the Fast Specialties car was faltering in the higher rpm ranges?
Again, mine and Travis' cars have the same camshaft. What gives?