Whipple tune rough start

So first crank of the day my car stumbles and idles rough until I blip the throttle a couple times and clears up. Also the fuel economy really sucks. Any ideas?

Let it learn by driving it.....

Did you do the crank relearn?

Livnpaintball2 said:

So first crank of the day my car stumbles and idles rough until I blip the throttle a couple times and clears up. Also the fuel economy really sucks. Any ideas?

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I've been getting around 8mpg in the city with my Whipple. Car idles around 1,200rpm upon startup and then drops down to about 800rpm once the CHT reach 125. Is bad mileage a sign of a needed crank relearn?

I'm curious as my MPG seems to be way lower than the majority of Whipple set-ups on the forum.

High idle on cold starts is typical for all cars. As far as the mileage, I don't know. You have a PP so your mileage will be lower than the base models like mine. I average 17.5 around town and north of 25mpg on the highway. That includes sitting until the car reaches a minimum of 160*CHT before driving. My guess would be driving style?

I can't seem to figure it out why its so low. Car smells like it is running slightly rich, but it is the stock (updated) Whipple tune. I have roughly a 1.5 mile commute to work with 6 stop signs and 3 lights along the way. Shift between 1800 and 2200 each gear. I even tried 2 tank fulls of driving in wet/snow mode with little improvement. Best I have managed , while catching all 3 green lights and resetting the fuel mileage computer after I already pulled out in front of my house with the car warmed up, has been 10.8 mpg city.

If I reset the fuel mileage computer once I get up to speed on the highway and keep it between 70 and 75mph, I've seen as high as 23.x MPG. Maybe something to do with those 3.73 gears around town.

Agreed, that short of a drive, with that many stops will absolutely kill MPG. And before the "it's a V8, who cares", I'll retort with it's 2017 and supercars are getting 40+mpg now.

My car did this when i first put my whipple on almost sounded like a slight miss... it went away in a week or 2 i think it needs to learn cold starts. Idk about the bad gas mileage tho cause ive never gotten good gas mileage lol

^ this!!!!!

Fuel mileage is tied to the amount of power being used. The bigger the injectors, the less mileage you typically get as well. Every time that boost gauges goes into boost, you are using more fuel then stock.

The car has dual wide bands controlling fueling, it is 99% correct.

I suppose I just have a light foot and I drive like a granny in her caddy

Whipple SC said:

Fuel mileage is tied to the amount of power being used. The bigger the injectors, the less mileage you typically get as well. Every time that boost gauges goes into boost, you are using more fuel then stock.

The car has dual wide bands controlling fueling, it is 99% correct.

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I did the relearn and put 1k miles on it since then, smells of gas when I start it and get 13mpg in the city, 15 hwy and I'm not in the boost. The old tune had better mpg but the stupid hesitation that drove me nuts.

Sometimes a have a rough start for about 10 seconds then its smooth, is there anything I should check?

I have a GTPP and Whipple stage 2. Mostly short drives around town. I drive it hard all the time. I'm averaging 12.5 mpg.

gsxr1300 said:

Sometimes a have a rough start for about 10 seconds then its smooth, is there anything I should check?

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I'm curious to hear what others have to say about this. Happens to me maybe 1 out of every 20 or so starts where it idles really low for a second or two then idles high off and on for about 10 seconds than its normal. Usually only happens when it is warm outside and the car has been sitting for at least 8 hours.