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Customer : Innovative Tuning

Vehicle : 2011 GMC Sierra 4300 V6

Story:  This truck was purchased almost 6 months ago.  Initially I was very pleased with the driving dynamics of this truck.  GM definitely pulled up their socks when it comes to the part throttle shifting/shift points of this truck.  Under part throttle I really didn’t have much to complain about.  The V6 has plenty of bottom end torque for this size of truck, so motoring around town was actually quite pleasant……as long as you didn’t drive it very aggressively.  Start to drive it a little harder & its personality changed.  Those nice shifts gave way to God awful drawn out shifts, the torquey low end power turned it to a slow revving upper mid-range power, & the pleasantness generally went away.  So with less than 4000 kms on the odometer, a pcm enhancement was in order.

First order of business was to fix the shifting.  Now the shifts are nice & quick, but smooth regardless of how “on it” you are.

Next order of business was to give the engine some eagerness.  In order to do that though, we needed to see what the truck would do stock.

Stock Virtual Dyno results:  160 whp & 211 ft/lbs.  Assuming a 20% drivetrain loss, that works out to 200 hp & 264 ft/lbs…..pretty much exactly what GM rated the 4300 Vortec at (195 hp & 260 ft/lbs).

After an afternoon of tweaking the results definitely improved!

165 whp & 225 ft/lbs.   Assuming the same 20% drivetrain loss, that would work out to be 206 hp & 281 ft/lbs.

Definitely a very nice pick up in torque…what you really want in a truck.  + 14 ft/lbs to the wheels is impressive.  Even more impressive is that this was done on 87 octane, on a completely stock as a rock truck…..right down to the OE paper filter.  This is my daily driver, & will be running on 87 the vast majority of the time, so that is what I’ve elected to tune it on.

The improvement in torque isn’t limited to full throttle though as I also spent a considerable amount of time tweaking part throttle tuning to squeeze out any additional torque I could.

Now the nice part throttle manners continue on if you drive the truck a little harder…..a genuine pleasure to drive all the time now.

As an added bonus, the city fuel economy has improved from 14.6L/100 kms to 12.9L/100 kms currently……with a few more little tweaks to come that should hopefully improve that further.

Update Dec. 19, 2011.

While reviewing some of the datalogs from the tuning process, it was noted that the MAP readings taken fell off as compared to the logged barometric pressure.  This is normally an indication of a restriction in the intake.  Given that the airbox is shared with the trucks V8 siblings, I felt is was more likely that the stock OE paper filter was the culprit (even though it was clean with only 5500 kms of use).  With that in mind, & given the good performance I’ve recorded from K&N drop in replacement filters in other vehicles,  a K&N filter was substituted for the stock filter & the results were once again impressive!

Resuts.  172 whp & 232 ft/lbs for a gain of 7 whp & 7 ft/lbs.

This result puts crank numbers at approx.  215 hp & 290 ft/lbs.  The torque number is creeping in on small V8 power!

Update Dec. 24, 2011.

After reviewing the datalogs from the run I did above, it became apparent that the improvement in airflow was “just enough” to merit a slight tweak to the tune.  After a few little tweaks, power picked up a touch more.

The truck is now sporting 176 whp & 232 ft/lbs.  That translates to 220 hp & 290 ft/lbs @ the crank approx.  Things are picking up nicely!

Update January 16, 2012.

After seeing such an improvement in the torque of this truck thus far, it has gotten tantalizingly close to being a 300 ft/lb V6!  It has now become my goal to get it there.  After todays tweaks/adjustments, I only have 4 ft/lbs to go (I’m sure I can find that somewhere!).  Current results, 175 whp, 237 ft/lbs (220 hp, 296 ft/lbs crank).

Getting SO close!  Most recent run of 180 whp, 238 ft/lbs.  That translates to 225 hp & 298 ft/lbs at the crank!

So it looks like that is as far as the truck is going to make it on tuning alone…… up is likely going to be a set of shorty headers.

Update Jan. 16, 2013.

The headers have arrived!  A set of JBA cat-forward shorties were ordered for the truck (about the only thing available for the V6 trucks).  Hopefully installation will happen within the next few weeks !


My impressions of the headers are quite good after unpacking them.  Its nice to see an actual set of hands has been on them ensuring a quality product.  It is apparent from looking at them that someone has spent some time blending/smoothing some welds, the driver’s side header to y-pipe flange has signs of being on a planer to ensure it is true.  You get the impression that the people who build them actually care about the end product.

Looks only go so far though.  Further updates after the installation as to how they perform!

Update Feb. 11, 2013.

So finally got a chance to bolt these headers on & go out to see what they did for me.  Pretty pleased with the results!

Headers Installed vs Best Run with Manifolds

+10 whp is about what I had calculated & was expecting but +24 ft/lbs far exceeded what I was expecting, but definitely not disappointed at all!

After looking at the stock manifold once it was removed, it isn’t a surprise that we saw these kind of results with the new headers.  Note the protrusions into the primary of each cylinder (small circle) & that both front cylinders of each bank are merged into one primary (large circle).  Not a performance setup by any means!

Manifold PicThe

Update Mar. 4, 2013.

Having driven the truck with the new headers on for a few weeks now, my driving impressions seem to mirror what the dyno results show…..a noticeable improvement in torque.  Hills that used to provoke a downshift can now be pulled without downshifting,  acceleration seems more effortless, maintaining speed on the highway seems to require less throttle input.  My fuel economy seems to back up the improved efficiency.  I track this truck’s fuel economy religiously & have seen a definite improvement since the headers went on.  Our fuel economy records can be viewed here.

Really looking forward to seeing what the fuel economy improves to when the cold weather finally disappears & my mileage goes back to normal.  Expecting good things!

Update July 29, 2013

After spending most of this summer driving around just enjoying the truck & its improved fuel economy, I decided to investigate further into getting some additional power.   Datalogs show that the trucks MAP reading very closely tracks ambient air pressure indicating that there is little to no restriction in the intake system (thank you K&N!), so I decided to focus my attention on the exhaust system.  The truck already has JBA headers installed, so I was interested in seeing if the cat-back portion of the exhaust  held any unlocked power.  I was a little skeptical as the truck shares its exhaust system with its V8 siblings & is therefore quite large by V6 standards.  In order to evaluate the OE exhaust system, I installed my backpressure tester into the downstream O2 sensor bung & then went out & did some WOT pulls & monitored the gauge.  I was expecting maybe  1 or 2 psi at wide open throttle, & that is pretty much exactly what I observed….slightly less than 1 psi!    So apparently my hunch was correct in that the OE exhaust was of no restriction at all to my V6 & my time & money would be better spent elsewhere in search of more power!

Next area to focus my attention on….valvetrain!  Cam simulations are underway!




  1. Hi,

    I was just wondering where you ordered your JBA headers from?



    • The headers on this truck came from Auto Anything. ….you have to order headers for an ’07 Sierra Classic to get ones to fit.

      Unfortunately I won’t be dealing with AutoAnything in the future as the company has made the decision to no longer deal with shipping to Canada


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