Supercharger or not?

That's actually not bad at all for cost. You're getting MPGs that I've never seen in my truck, that's for sure. I don't even understand how 18+ is even possible! I never saw that without the blower. I have done 3 road trips recently, logging over 3000 miles, and my average has been 12.5. In town I'm lucky to get 11.5 on average.

Yea I’m averaging 12.5-13 hwy with jdm 700 kit

Never heard of those Mpg’s stock or blown

Did you hand calculate?

mchurch0211 said:

Yea I’m averaging 12.5-13 hwy with jdm 700 kit

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You're probably running 93 in NC though right? That does help a little with MPGs. We have the worst gas here. Might be a point higher than AK, but it's ACN 91, which is not the same as regular 91. Probably more like the 90 in AK. Anyway, sure wish we could get 93 out here!

EricM said:

OK, now I am genuinely curious as to how a tune can cause the belt tensioner to break. I didn't know this was a thing with S/C 6.2L engines. Is it in the firmness/speed of the transmission shifting?

I've seen it happen a lot on stick shift Mustangs with aggressive clutches and big blowers- but never on an automatic. With clutch dumps on upshifts and a real aggressive clutch, the change in speed for the rotors between shifts is really fast and all that energy needed to slow down the rotors for the next gear gets transferred into drive the belt and everything attached to it.

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Exactly. The 1-2 shift harshness would cause at minimum, the belt to jump, at most, the tensioner to break. I have some pictures Of the carnage I will locate and share.

JDM quickly told me that they had seen that before, and it was pretty much specific to the 13’s. The 14’s ended up using a slightly different serpentine routing, removing a large ribbed-idler pulley from the 13 setup, and added a FEAD belt guard.

JDM (and later VMP) attributed it to the harshness of the tune on the 1-2 shift in high traction and load situations, which was most pronounced on the 1-2 with the torque multiplication at that shift. The second issue was with the serp configuration on the 13 setup. I believe it was JDM who identified what they referred to as a extremely violent ratcheting effect on the tensioner arm on this 1-2 shift when in 4wd with high traction available. The a small (in actual size) wave would travel throughout the serp belt when the ratcheting would occur. Eventually, the wave would end when the belt would make contact with itself, lock the belt from moving which would then either jump the belt or even some cases, which I personally experienced, shear the tensioner arm.


I went from a near 1:1 ratio of 4wd HI WOT 1-2 shifts to destruction, to maybe ~20 of those types of scenarios since with no issues.

mchurch0211 said:

Did you hand calculate?

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On those no. Off the computer estimate. On some individual tanks, I can only recall doing it twice. When I first put the tune on and began blending and maybe another month in, which would have been last September or so. They were relegated to my trip to work and back which was highway driving at 60 mph, so a lower speed. Fill vs mileage was in the 19.0-19.5 mpg area. The computer may be a little optimistic given that the 10 mph reduction would have bought more fuel savings than that. Regardless, macro is the tune and neat gasoline both helped with the improvement. I’ll probably not go to the effort of blending in ethanol to back into the exact difference.


Something else...the DA up where I live is amazing. I’m at temperatures that are often associated with 7,000-10,000’ altitudes, except I am near sea level. I actually was a little concerned if I had enough injector and pump during the November-February timeframe at WOT. It could routinely get to -4000 to -5000 ft.

I’ll make an effort to capture actual mpg the next tank. Just to clarify, those numbers that are raising some brows are a two-way ten mile drive between my house and my work, which happens to be nearly level. There is less than 10’ of elevation change on the drive. This is going off of the computer estimate at 68-70mph. This did not take into account other times where I’m running to the store and driving more spirited. This isn’t an actual average, but the computer estimated fuel mileage while on the highway, up to 68-70 mph and unpausing the capture of the fuel mileage. Actual computer calculated fuel mileage is lower, though, there really isn’t “city” driving here. It’s heavily bent highway driving with minimal traffic.

Thank you all for your input. I am going to order the Whipple stage 2 with the extra fans etc. I will also order the oil pump. I appreciate all of your feedback.

Ricoman said:

What @EricM & @Dane said..! And will add....you will need to come up with a good excuse when people ask why your grinning all the time..!
I have the Whipple on my 2014 Shelby...it was sent straight from Dealer to Shelby in Vegas to get worked over and they did all that @Dane said as the Package...its got 62K on it now and no problems with Supercharger yet...it is also mostly a Highway Queen,have never really abused it or towed with it....only major problem I've had is the Pinion Gear went out last month so had the Differential rebuilt....maybe from stepping on that skinny Pedal too much...the sound and speed is addictive,and my GF knows if I'm behind someone more than 15 seconds,she needs to get ready to have her neck snapped...
Are you installing yourself?
I know my way around wrenches and use to rebuild Diesel Engines but doing that SC just wasnt for me...yeah,its $$ to have it done,but your talking about $10K in equipment...you do it and screw up,your screwed,cause they always find a way to blame you.....they do it and at least you have some warranty .... just my personal preference,less worry,and more time to GRIN.
Good luck,but you knew before you even posted you were going to get one...!

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I will most likely have it installed by a professional. I have mechanics in my family but I do not want the stress of messing something up as I don’t work on engines daily.