Fun Night at the Tuner
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Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
Fun Night at the Tuner
I have an '05 Z51 M6 with about 108K miles (bought 6 months ago with 104K miles).
To me, this car felt pretty strong compared with other C6's I tested; almost like an LS3. It came with a Vararam, and the prior owner suspected a tune had been done sometime before he bought it. However, it farts a decent puff of smoke (kinda greyish) when you let off after flooring it. Being an older car, this concerned me so I took it to my mechanic (not a tuner) who did not see it as much to be worried about (car uses a bit less than a qt. of oil every 1,000 miles or so). But, I felt having a tuner look at it just to see if anything else unusual was going on would make some sense, particularly since 15 MPG around town, and 27 on the highway (steady-state 75MPH), felt a bit low to me.
Anyway, last night I took it to a tuner in West Chester PA (I do not believe he is a FORUM sponsor so PM me if you are local and want to discuss his services) and it was a very eye-opening experience. He focuses on LS engines (actually better known for GTO work but his Vette business is growing).
Now this is commonplace for folks in this section, but I was impressed with the time and effort the young man put into the car, and I felt like I learned a lot. It was pretty obvious that there had been a tune on the car, but it was not nearly optimized -- either at WOT or for street driving.
His first step was to plug it in to his laptop, and have me drive around while he logged various data on timing, fuel-air, and many other tidbits. He then strapped it onto the dyno (Dynojet winpep 7), where it produced SAE adjusted 368 RWHP @ about 6,000 RPM and 358 RWTQ @ 4500 RPM or so.
Based on power-loss calculations I'd seen, this is somewhere between 420 and 433 crank HP -- pretty stout for an old LS2 warhorse! We went through some of his other customers' runs just to see if that was credible. Given his C7 (when stock) produced 411 RWHP, and a customer's 2006, with headers and a tune, delivered about 376 RWHP, we felt it probably captured the truth pretty well.
Next step was to optimize WOT over 3 more dyno runs. End result was more power and torque AT LOWER RPMs! 379 RWHP @ 5,800 RPM and 371 RWTQ @ 4200 RPM.
But, most driving is done at part-throttle, so back out on the street we went for a few passes at different settings and more fiddling on the laptop.
$350 and a total of 2 hours later, I have better numbers across the board and a very smooth-running C6. While not earth-shattering, if the "rule of thumb" is $50/HP, I got 11 of them for $30 each so a bargain -- and definitely feels livelier to boot. We'll see about fuel economy, but tuner told me not to expect much improvement.
PS -- can anybody take a look at this video and tell me how much I should be worrying about that puff of smoke at the end??? Thanks...
To me, this car felt pretty strong compared with other C6's I tested; almost like an LS3. It came with a Vararam, and the prior owner suspected a tune had been done sometime before he bought it. However, it farts a decent puff of smoke (kinda greyish) when you let off after flooring it. Being an older car, this concerned me so I took it to my mechanic (not a tuner) who did not see it as much to be worried about (car uses a bit less than a qt. of oil every 1,000 miles or so). But, I felt having a tuner look at it just to see if anything else unusual was going on would make some sense, particularly since 15 MPG around town, and 27 on the highway (steady-state 75MPH), felt a bit low to me.
Anyway, last night I took it to a tuner in West Chester PA (I do not believe he is a FORUM sponsor so PM me if you are local and want to discuss his services) and it was a very eye-opening experience. He focuses on LS engines (actually better known for GTO work but his Vette business is growing).
Now this is commonplace for folks in this section, but I was impressed with the time and effort the young man put into the car, and I felt like I learned a lot. It was pretty obvious that there had been a tune on the car, but it was not nearly optimized -- either at WOT or for street driving.
His first step was to plug it in to his laptop, and have me drive around while he logged various data on timing, fuel-air, and many other tidbits. He then strapped it onto the dyno (Dynojet winpep 7), where it produced SAE adjusted 368 RWHP @ about 6,000 RPM and 358 RWTQ @ 4500 RPM or so.
Based on power-loss calculations I'd seen, this is somewhere between 420 and 433 crank HP -- pretty stout for an old LS2 warhorse! We went through some of his other customers' runs just to see if that was credible. Given his C7 (when stock) produced 411 RWHP, and a customer's 2006, with headers and a tune, delivered about 376 RWHP, we felt it probably captured the truth pretty well.
Next step was to optimize WOT over 3 more dyno runs. End result was more power and torque AT LOWER RPMs! 379 RWHP @ 5,800 RPM and 371 RWTQ @ 4200 RPM.
But, most driving is done at part-throttle, so back out on the street we went for a few passes at different settings and more fiddling on the laptop.
$350 and a total of 2 hours later, I have better numbers across the board and a very smooth-running C6. While not earth-shattering, if the "rule of thumb" is $50/HP, I got 11 of them for $30 each so a bargain -- and definitely feels livelier to boot. We'll see about fuel economy, but tuner told me not to expect much improvement.
PS -- can anybody take a look at this video and tell me how much I should be worrying about that puff of smoke at the end??? Thanks...
Thread Starter
Race Director
Joined: May 2005
Posts: 11,992
Likes: 1,331
From: Middletown, DE
There's some evidence the cats may have been gutted a few owners back. I suppose with a decent tune that might be worth something.
I need to, just once, get this thing to the strip...
