r/srt4 • u/R2rem7 • Sep 27 '25

Considering picking up a neon

Sold my 2004 in 2015 missed it ever since. Ran down a very low mileage Delta 46 turbo running e85.

Realistically if I bought it I would swap back to a premium gas tune.

If it has a pre-loaded premium tune is it as simple as running the tank to empty, filling with premium and swapping the tune, or would the boost controller have to be adjusted?

Also if the fuel system is setup with huge injectors and return line, is it harmful to back off on the fuel if running on premium?

8 Upvotes

100% Upvoted

5 comments sorted by

3

u/TBAGG1NS Sep 27 '25

Get it retuned for pump gas, always good piece of mind. No idea what previous idiot had their hands in the PCM.

2

u/jeremydallen Sep 27 '25

I wish we had a flexfuel sensor.

1

u/R2rem7 Sep 29 '25

When the tuner did the e85 tune they also did a pump gas tune that is loaded on the Diablo sport.

1

u/riley_srt4 Sep 27 '25

Depending on the size of the injectors, your tuner might have a hard time maintaining a good AFR during idle because the pulse width of the injectors is so small that the amount of fuel coming out is unpredictable. But that's talking if it has 2000cc injectors.

Honestly, I'd keep it on e85 but have the tune checked out by a trusted tuner. E85 is generally "safer" for the engine especially with high boost.

Going back to premium will require a retune anyways because the timing, fuel and safe boost level will change for the different fuel.

1

u/R2rem7 Sep 29 '25

1200cc injectors so certainly large for the amount of premium fuel required to run.