Bigredginger

How's it going I have a 2013 5.0 SuperCrew 4 wheel drive I have a jlt intake SCT X4 with MPT custom Tunes. I have their 87 octane PRX 93 octane PRX in E85 PRX. I just had stainless Works long tube headers installed I was at the track last night I was running 9.8 in the 8th mile prior to the long tubes and last night I was having trouble breaking below a 10 I have pretty consistent .55 reaction times and I believe a 2.5 60 foot have to check the time slips but the temperature was around the same as the previous 9.8 runs anybody have any input on this

Koolponycar

Did the tune require a revision for the long tubes? sounds like you lost some torque on the bottom somewhere.

Bigredginger

I had all the tunes revised and the e85 was brand new when I got the headers. I ran 93 prior to header install and I ran e85 post headers so I'm going to try 93 again next Wednesday and see if the e85 was to blame

Koolponycar

looks like E85 would make more power, but going back to the 93 may tell if so, or if not it should be even less which would have something maybe to due with the headers/exhasut since thats all you changed. Also check all vacuum connections,etc., just in case something got loose or broken during the install. Good luck and let us know what you find out.

blue5.0

I would imagine something has to be off. I dropped near 7/10th in quarter and over 6/10th in 1/8th with just addition of my looks long tubes. Have you data logged?

Bigredginger

That's how I feel too I definitely think something's off but I checked for broken vacuum lines and the truck runs perfect otherwise I haven't data logged yet but I did talk to MPT about it on the phone

Bigredginger

Another thing I noticed is the smell of gas I don't know if that's an indicator to anything or just because of the high-flow cats

blue5.0

How many miles did you drive on the new tune after the headers before you ran the 1/8th? Was this actually at the track or using a computer to track your time? Have you tried returning to stock and reloading tune?

Bigredginger

I put about a hundred miles on the truck before hitting the track and it's actual track I haven't tried retuning to stock but I did bounce from 93 to E85 and now back to 93 to try the track again tomorrow but I'm going to do spark plugs tonight and I'll reflash to stock

blue5.0

Just make sure you data log the run at the track and data log around town as well!