? for all you VR4 guys (and ? about superchargers as well)

this is a two part question;

1. I was doing some searching in this forum, and found a wide variety of answers to the gas mileage question, so I'm wondering what mods you have, and what kind of gas mileage do you get (VR4's only please).

2. Second, if I were to buy a vr4, swap the engine for an n/a, and throw on the Rippmods kit, do you think I'd get better or worse gas mileage than if I'd kept the vr4 stock (AKA TT'd).

From what I gathered, a supercharger wouldn't be any better *if not worse* than turbos on gas mileage, because of the turbo's delayed spool, however; the ripp mods kit is a centrifugal type S/C (correct me if I'm wrong) which like a turbo, takes time to spool (I've heard they spool at about 2,500 RPMS). With this info, couldn't I technically shift around 2,000 RPMs and still incorperate good gas mileage... or does the centrifugal S/C make boost at idle, but not hit full boost till around 2,500 RPMS...

thanks for looking and I aprreciate your time

There is a lot more too this than what you are looking at. There is way more to gas milage than RPM's. I was getting 19/30 when my vr4 was stock.

You should get better gas milage with a turbo setup than a supercharger.

Well I tend to race mine around quite a bit, but here goes.

1) around town driving pretty hard/racing, I get 13/15mpg

2) shifting around 2.5k with occasional romps around town /or doing 100mph highway I get around 17mpg

3) Doing the speed limit via cruise control on the highway I've seen 27-30 (that doesn't happen too often though :biggrin: )

When i first got my vr4 (stock) it was getting about 22 avg. Then i got a FIPK, with i hear is suppose to increase your mileage. I didnt notice any real difference, maybe another MPG or so. I also drive like a grandma most of the time, shifting at or before 3k.

As far as the SC question...i was under the impression that, being belt-driven, there is no delay. Whats the difference between a centrifugal and roots SC? My friend has an 06 Cobalt SS/SC with the roots system and it boosts very quickly. Theres no boost at idle, his gauge reads in the "negative boost" like the VR4s, but as soon as you give it gas it jumps. i would say it probably hits positive boost around 1500 revs. but, like i said, thats a roots system. I dont know if its any slower on the centrifugal type, though i would think not being that its still directly driven by engine. gonna go check howstuffworks.com lol

not sure about the roots, but the centrifugal is like belt driven turbo...

all things aside, lets just say that I regularly check tire pressure, I'd have a K&N intake and probly exhaust... New plugs wires etc... would I be lookin' at around 19 MPG city if I baby it???

Talskinny, do you think I'd most likely be lookin at a 1MPG drop in mileage in the city or worse??


Thanks for the responses btw guys