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I'm afraid that there's an epidemic of incorrect dyno testing going on in both the trade press and in examples where our own SSR Fanatic members have been misled by their "trusty" dyno guy.
I've documented a number of those on this wbsite recently, but today I found another really gross one in the February issue of Chevy Hi Performance magazine.
In an article starting on page 81, they claim to install and dyno test 3 products from Jet: a microtuner, a mass air sensor, and the always popular "throttle body spacer". They apply them to a 5.3L Silverado pickup engine - the same engine used in the 03 / 04 SSRs.
To spare you the details, the article claims that dyno testing showed the following results:
Stock: 249 hp at 5500 rpm, 298 ft lb of torque at 4000 rpm
Microtuner: 270 hp at 5500 rpm, 346 ft lb at 4000 rpm
Mass air & spacer: 284 hp at 5500, 358 ft lb at 4000 rpm
Sounds impressive - until you examine their accompanying graphs.
When you apply the classic physics formula (applies to ALL dyno curves):
HP = Torque x rpm / 5252
you see that the power and torque curves are ALL numerically impossible!
The stock torque curve shows 298 ft lb of torque at 4000 rpm, but that means the stock power curve should show 298 x 4000 / 5252 = 227 hp at 4000. It actually shows 178 hp!
Likewise at 4000 rpm, the microtuner curve shows 346 ft lb, which means 263.5 hp at 4000 rpm. But, the microtuner power curve actually shows 198 hp!
At 4000 rpm, the spacer & mass air torque curve shows 358 ft lb of torque, which means the hp should be 273 at that rpm, but the power graph shows only 207 hp!
So, it is an exceedingly polite statement to say that these results are "not accurate".
The sad thing is that I'm sure a bunch of Silverado and SSR owners are going to rush right out to buy these 3 Jet products based on this "proof" that they work so impressively.
By sheer coincidence, Jet has a large color ad on page 90 of this issue.
Buyer beware.
Jim G
I've documented a number of those on this wbsite recently, but today I found another really gross one in the February issue of Chevy Hi Performance magazine.
In an article starting on page 81, they claim to install and dyno test 3 products from Jet: a microtuner, a mass air sensor, and the always popular "throttle body spacer". They apply them to a 5.3L Silverado pickup engine - the same engine used in the 03 / 04 SSRs.
To spare you the details, the article claims that dyno testing showed the following results:
Stock: 249 hp at 5500 rpm, 298 ft lb of torque at 4000 rpm
Microtuner: 270 hp at 5500 rpm, 346 ft lb at 4000 rpm
Mass air & spacer: 284 hp at 5500, 358 ft lb at 4000 rpm
Sounds impressive - until you examine their accompanying graphs.
When you apply the classic physics formula (applies to ALL dyno curves):
HP = Torque x rpm / 5252
you see that the power and torque curves are ALL numerically impossible!
The stock torque curve shows 298 ft lb of torque at 4000 rpm, but that means the stock power curve should show 298 x 4000 / 5252 = 227 hp at 4000. It actually shows 178 hp!
Likewise at 4000 rpm, the microtuner curve shows 346 ft lb, which means 263.5 hp at 4000 rpm. But, the microtuner power curve actually shows 198 hp!
At 4000 rpm, the spacer & mass air torque curve shows 358 ft lb of torque, which means the hp should be 273 at that rpm, but the power graph shows only 207 hp!
So, it is an exceedingly polite statement to say that these results are "not accurate".
The sad thing is that I'm sure a bunch of Silverado and SSR owners are going to rush right out to buy these 3 Jet products based on this "proof" that they work so impressively.
By sheer coincidence, Jet has a large color ad on page 90 of this issue.
Buyer beware.
Jim G