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Old 10-13-2006, 11:09 AM   #239
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

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Quote:
Originally Posted by MeanEditor View Post
Matt,

I would like to compare our power delivery with yours. My bet is that we have more area under the entire curve and that our torque delivery is more constant. This is a function of our bottom end and maybe the port work.
Quote:
Originally Posted by MeanEditor View Post
Matt:
I was talking about looking at OUR plot and comparing our baseline to our latest pull, not yours to ours... If you look at ours and ours alone, you can see that not only have we increased peak HP/TQ but shifted the entire graph up.

To replicate what we have done would take $$$ and as some of you have pointed out it really seems like we are spending alot to get where we are.
Care to explain further?

My car and your car use the exact same cams. BOTH of our cars have shifted the power in a very similar fashion. You claim that the dyno you use is a cruel mistress, but the Dyno Dynamics that I run on is also known for reading very low. If it was about claiming the higher number, I would go get on the Mustang Dyno we have down in Denver. I've been on Cobb's Mustang dyno (before the headwork) and my car delivers more than 20 more whp on that dyno when comparing my car with identical mods. I reviewed your dyno plots before I ever opened my mouth. I have followed the whole ZTH build and know how to extrapolate the numbers from your results to have a very solid idea of where your car stands.

But for the benefit of the readers, I will go over a little bit of it. It does pose a bit of a challenge because you guys never got a true baseline number for the car. But, with just a TWE header, it got 132ft/lb and 113.9hp. Now that does leave us guessing a little bit, but it would be fair to say that the headers got you guys about a dozen HP, so, for comparison purposes we can say your baseline was AROUND 102whp. That's already reading higher than the dyno I use reads for stock RS's. Ours is usually at 95 or 96whp, with the strongest stock car we've ever seen around here hitting 100whp. But all in all, one could say that the dynos are pretty comparable, delivering pretty similar results.

So, if we take that assumption for granted (which I am sure someone will choose to argue with) then when it's all said and done, your car is making about 10 more whp than mine. And as we all say in the article and in reviewing your plots, a good chunk of that was from getting a good tune. As such, I stand my my assessment that for the vast majority of the population, spending the money on a built block like that is a waste of money. It brings almost no additional power to the table. The tune is worth it's weight in gold and is a very cost effective power adder. But unless someone has a cam that is more aggressive than Cobb's Spicy cam, having a bottom end that revs to 8000rpms is just so much mental masturbation and not truly contributing anything to the project.

Now, I would also like to mention that I am pretty sure that my port work is more aggressive. I have asked Ryan to post the bench flow number on ZTH's portwork a couple of times, but have never gotten an answer. But based on the text of the article, it suggests that the work is VERY mild. Mine is not. I am at 267cfm intake, and 208cfm exhaust at 28" @ .450" of lift. This is up from 250cfm intake and 162cfm exhaust, with most of the gain obviously being on poorest flowing exhaust port that everyone talks about...


Of course, once you guys strap NOS onto the car, that bottom end will earn it's keep, but you also cease to be NA at that point. If you stick around, I think you will find that some of us are pretty hardcore in our purism regarding NA. Any compromise of that purity and we don't veiw the vehicle through the same eyes. Anyone can make power with a bottle or a snailshell. What made ZTH interesting to many of us was that it was NA.

Now, Cobb currently has an employee project car that will be experimenting with both a new cam profile and a new header design. I will be watching this as it progresses. If a more aggressive off the shelf cam comes to market, you can bet I will head back to the shop and build a block to support that. But my bottom line point stands, and that is that on most anything but a racecar, a built bottom end is not money spent wisely on an NA build with our current options for cams...
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Last edited by Matt Monson; 10-13-2006 at 11:20 AM.
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