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Discussion Starter · #1 · (Edited)
has anyone looked at the Dinan dyno charts long enough to figure out what they're doing? I believe that they are fudging their numbers in at least two ways:

1) first of all, they seem to be converting (marketing term: cooking) their HP and torque numbers to "at the crank" numbers versus "at the wheel" numbers. to my knowledge, they make all measurements on their chassis dyno (at the wheels). converting the numbers makes the increase seem more attractive. from what I've seen, the rest of the industry provides "at the wheel" numbers.

2) to make matters worse, when Dinan quotes a gain, they use the maximum delta between stock horsepower and "modified" horspower. the problem with this is that a lot of these maximum deltas are BEYOND the maximum horsepower point. take for example, the intake manifold for an E30 325i. this manifold is claimed to add a whopping 41HP at 6500RPM yet if you look at the dyno chart, you'll see that the peak total horsepower is actually at 5750RPM and the gain is a significantly lower 27HP at that RPM. now normalize the number back to a rear wheel horsepower number (where they probably actually measured it) and that's more like 22HP-23HP. even 22HP seems optimistic to me considering this manifold appears to be nothing more than the stock manifold with some porting, polishing and a fancy paint job (runner lengths are likely unchanged). even using the normalized number, this is the biggest HP gain that I've ever heard of from a modified stock intake manifold. it's not just this manifold where they measure peak delta (even if outside the max HP range), it's all of their parts. just browse the web site and look at dyno charts. you'll see what I mean.



from a company that is as highly respected as Dinan and that puts so much R&D into their modifications, I really feel that their marketing is borderline unethical.
 

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In the switch to flywheel horsepower, basically all companies do that. Some people just don't know what the difference in HP measurements are, like the guy who wrote to SCC wondering why their WRX only made 147 instead of the 222 his has. :tsk:

It's a similiar thing with the maximum gain. They clearly state that it is the peak HP gain, and the rest of the industry does the same. The chart they provide clearly shows the new maximum peak HP, as well as the peak gain. Nothing new here.

Look at Sport Compact Car, European Car, etc. All of the magazines that test new products show the results in a similiar manner. Not very unethical to me. :dunno:
 

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Discussion Starter · #4 ·
well, it's not perfectly honest because most people will probably NOT catch these details. it seems to me to be more of a marketing thing to intentionally mislead people. that's just my take. what other purpose does it serve?

every place that I've ever called (ESIS and UUC are examples) tell it to you straight, in RWHP.
 

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Discussion Starter · #6 ·
for the money you spend on dinan software, CAI and muffler, I can completely mod a miata (full suspension with koni shocks, CAI and full exhaust including ceramic coated headers).

hey, if you got more than their posted results great. but I'm sure that I don't need to explain that differences in altitude, humidity and air temp have an effect on the results. my point was what they use to calculate the peak gain. for example, the muffler for your car is listed as making 4HP peak at 6500RPM yet your car developes it's peak HP and TQ at 5500RPM. what I question is what effect the muffler has at 5500RPM. same goes for the posted gain numbers on teh CAI (also at 6500 and also less of a gain than on the 330 which already has an improved air box).

funny, though.... the muffler made almost no perceptible differenice on my car other than noise and freer revving past red-line. the 330 muffler was dynoed at 6HP on my car. the 328 is supposed to have more room for gain and the muffler alone is only worth 4HP.

from their 328 page, it looks like most of the 328 power increase was made in the software.
 

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No argument in regards to the Miata, which I love very much!!

I just wanted to say that I got what was expected with my Dinan mods, i.e. what Dinan was claiming...
 

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Discussion Starter · #8 ·
well, you got what they were claiming at the peak HP RPM but if you were to have installed just the muffler or just the CAI, I doubt that you would have gotten their posted gains (which are at teh point that the engine starts loosing power).

my only points with this post are:

1) Dinan should claim RWHP like most if not all of their competition does. browsing the popular miata tuners, they too post in RWHP versus cooked numbers.

2) the HP gain of a given product shouldn't be posted as the peak gain (iregardless of RPM) but the gain the RPM where peak HP and TQ are made. these seem to almost always be two different RPM ranges. the peak HP number seems to always be at an RPM that is post optimal wher ethe engine starts loosing power.


anwyay, I think the common belief is that you need a minimum of 5RWHP to actually register the gain on the butt dyno. that said, the Dinan CAI and muffler seem to make more noise than power on a 328. if someone wanted the most bang for the buck from Dinan on a 328 it seems to be in the software alone (but the shark makes more power and jim c doesn't report to bmwna that your car is modded).
 

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Also, my car never made it's peak torque at 5500 RPMs... mine makes my peak of 189.1 at 3600 and 188.4 at 3500, which is in accordance to Dinan's chart...
 
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