stage one freeway mileage - SRT Forums

bubba · 07-21-2003, 04:48 PM

I topped my tank off in sacramento and drove home to san jose. I only boosted once (16psi) to avoid being stuck behind some slow trucks and had the ac on the whole time and got stuck in some construction traffic. After 150 miles the tank took five gallons. That's right folks, with conservative driving stage one yields 30mpg.
Just for comparison driving the same exact trip in cooler weather without the ac on the best I got was 26mpg.
On the trip to and from lake berryessa I averaged 24mpg. pretty good considering the straightaways were taken wot in 5th (again 16psi)

srt4nextyear · 07-21-2003, 05:47 PM

Sorry man, I dont believe you. I think i need to take it out for a 24 road test to make sure its ok. I'll break it in for you.

sounds good to me

jaymzx · 07-21-2003, 06:15 PM

Well, it makes sense. Your displacement has remained the same when you aren't under boost (and your volumetric efficiency), so the Stage 1 computer has no doubt shortened the pulsewidth of the fatter injectors to make them more 'stock'.

Now, rolling at 16psi is where you'll watch your fuel gauge drop

The PCM will dump fuel at WOT to keep the A/F in check and thats when the full 5xx cc (don't know off-hand) comes into play.

This is where we see the benefit of a computer that 'knows' what injectors it has, as opposed to tricking the ECU, and then you run insanely rich while in closed-loop.

Wade · 07-21-2003, 06:49 PM

I've observed a 1.5-2 mile per gallon increase with my Stage 1 kit as well. But, you are correct in that if you get in the boost the mpg tends to plummet.

jakenewtoy · 07-21-2003, 08:03 PM

i was averageing 19 mpg. at 750 i put stage one in and the last 3 tanks have been at 21-22 mpg. was not sure if the car finally hit the magic 1250-1500 break in or the stage 1. jaymzx i think you hit it on the head. I thin pcm does not run as rich thus you get a better gas mileage, now should you hit the boost a lot then of course the bigger injectors will flow more gas and less mpg

bubba · 07-21-2003, 08:11 PM

but the funny thing is on the way to and from lake berryessa I was in boost most of the time and going up some of the hills that had a straightaway I was spiking to 19psi! I think the ecu was getting used to making lots of boost with part throttle and when I went full throttle it had to readjust (which it did within 6 seconds)
On another long straightaway on flat ground ipaid must have been doing at laest 5mph faster than me and he was saying how he was going to take it easy because he is detonating

SRT-4_2-25-03 · 07-21-2003, 10:26 PM

tried some MMT in my fuel and the pinging went away on 91 octane.

daytonagts · 07-21-2003, 10:39 PM

I average on long trips with the Stage 1, about 28mpg....But lets not talk about around town