[vertigo12369]

With the prices of gas these days...

What does a CAI, HVTB, and U-bend/resonator removal due to your MPG?

Thanks

 

[dayday]

Not much, If anything it may be a bit better.

 

[99GT2dr]

I don't know about "if anything maybe a bit better". I couldn't tell you with the HVTB, and Ubend/res removal. But with a FWI, UD pullies, 180 tstat, bone stock exhaust, and spare/jack removed, I got 40 mpg on the highway and about 26 city. That was before I put on a set of ported manifolds. I'm waiting til this weekend when I go to san antonio to see what kind of mpg i'm getting now on the highway w/the pem's. Of course it depends on your motor too, what kind of wear n tear, how good you take care of it, tune-ups, etc. I change my oil every month, tranny oil twice a year, flush coolant every ~2 yrs., plugs when I feel like it, I keep extremely good maintenance on it. So your gains in mpg will vary on a lot of things, including weather.

 

[vertigo12369]

I'm pretty anal about maintenance. Nothing waits to the last minute. So it sounds as thought I won't see a decrease in my fuel economy, and hopefully I'll see an increase. Cool. Thanks guys.

 

[k0bun]

Fuel Mpg

I know gas prices suck, especially since most of us have to run 93. What effects mpg the most is driving habits. Face it, are you really going to stop modding your car because of gas prices? Maybe for a little while until that tuff-a** in his Honda beats you at the traffic light in town. After that the last thing you'll be conscerned about is the couple of bucks you'll be saving by letting him get away with that. In my opinion, you have to pay for gas no matter what you do to your car, so I want mine as fast as I can get it. Within my budget of course.

Gas prices suck
Losing to imports sucks more

 

[GoldmemberBonneville]

In my heavy 1998 Bonneville SSE I saw 34.3 mpg on the freeway last weekend. Typically with a 70% hwy/30% cty I see 29-31. It also depends on the average throttle % used. My sister with a 1997 GP GT 4dr (bare bones GT with no leather, no HUD, standard 4 speakers, no digi climate control, no moonroof, etc.. -well she's lucky to see 27-28. The best she ever got in the 30k shes had it was 29 on her 850 mile trip to/from Milwaukee. Looks like her 3.29's are really killing her mpg's.
So far I've managed to gut her airbox and drop a K&N drop-in in it without her knowing, as well as a 180 *t-stat drilled 2x 1/16", TR55 plugs (gapped at stock .060"). I've also put a new pcv valve, fuel filter, plug wires (mid-grades from NAPA), and cleaned the TB, but I am going to see if I can get her to drive my SSE for a day while I sneak it in to Alex Exhaust and slap a new high flow Magnaflow/Carsound 2.5" cat in as well as delete the u-bend and also put a 3" DP in. Hopefully with the exhaust work she'll see another 2-3 mpg average.
As soon as I get my mani's ported (or S&S headers depending on what I here for reviews) and find how much my SSE benefits I might throw some ported mani's on and possibly do a light port job on the TB.

Synopsis:

1998 SSE 170,xxx miles (L36 + 3.05's) with 3" DP, Magnaflow/Carsound 2.5" high flow cat, 3" Magnaflow Wide Open, 180* T-stat drilled 4x 1/16", NGK TR55's gapped at .057", TPS mod, removed MAF screen, Belden Max wires, Thrasher CA box with K&N RE-0810 9" cone

25-26 City/34 HWY



1997 GP GT 145,xxx miles (L36 + 3.29's) with gutted stock airbox, K&N drop-in, NGK TR55's gapped at .060", mid-grade 7mm wires, 180* t-stat drilled 2x 1/16"

22-24 city/ 27-28 HWY


1993 Buick Park Avenue Ultra 92,xxx miles (Series I L67 + 2.97's) NGK TR55's gapped .060", removed MAF screen, fresh M62, ricer CAI (no box) , 180* t-stat drilled 2x 1/16"

20-22 City/27-29 HWY

 

[dantheman1998]

40 MPG?

My Jetta TDI which was a 1.9L diesel got 40 MPG? Hows a 3.8 Supercharge getting that?

 

[vertigo12369]

My sister with a 1997 GP GT 4dr (bare bones GT with no leather, no HUD, standard 4 speakers, no digi climate control, no moonroof, etc..

Well, I have the same car as your sister...except mine is a coupe and an '02. I see 1-2 MPG better on highway, but my city is about the same.

I guess gas prices don't stop some people from modding their cars, but I haven't started yet (just finished college gimme a break) and I don't want to instantly give myself a gas-guzzler. That doens't seem to be the case with standard mods though.

Thanks guys!

 

[k0bun]

Didn't mean to jump on you like that man The standard mods such as intake and exhaust and a colder thermostat are a good place to start and shouldn't effect gas mileage negatively, assuming you can keep your foot off the gas . Believe me money's tight for me too but there were certain goals I wanted to reach with my car, so I wasn't too concerned about gas $. But maybe that's because I used to drive a V8 pickup so for me the amount I pay for gas now is an improvement. Anyway, good luck with your car and mods.

 

[99GT2dr]

Well this weekend with my ported manis on, I averaged 33.5 mpg on my way back from san antonio. Weather was 95*, I had about 700 extra pounds in the car (me, wife, kid, friend, rottweiler, and PACKED trunk), and I had to go WOT a few times (slow drivers piss me off ) With cooler weather, less weight, and steadily cruising at about 75mph, i'm sure i'll get better than 40mpg now.

 

[vertigo12369]

...I had to go WOT a few times...

Man, I hate it when I HAVE to go WOT...

 

[Diavolo]

My mods are
Wizair, ZZP S2 TB, VS cam, 3.0 pulley, TOG headers, 3" DP, no cat, 3" exhaust, DHP, ICCU, 180 tstat, AL 103's and some other misc stuff

I got 33 mpg on my trip from Oxford OH to Chicago

edit: And beat a 350z on a highway run

 

[jacobkidd]

the computer display is about 10% off on my car. also lots of people put on smaller tires and that makes it look like they are getting better mileage (probably are a little around town, but on the highway no)

For real results--
travel to and from somewhere over 200 miles (huge difference with elevation change)

use "real distance" as stated on a map..... not the odometer or computer display, especially if you have changed your tire size, or they are worn.

Anal---- but more accurate.


NOTES:
also anytime I start my engine cold it uses a ton of gas before it is warmed up.

Idling takes about .1 gal per 12-15 minutes

going from 225/60-16 ( stock) to 225/50 -16 is about 7-8% change in the final drive ratio and will negatively affect MGP on the freeway.

 

[easytoremember]

i understand gas prices. up to 2.31 and higher in wisconsin for premium. Maintaining your vehicle will be your key to MPG. Keep your filters clean. (air and fuel) Keep your oil changes constant. Also, keeping your engine speed constant while driving will help. I was able to get 410 miles off of 15 gallons while carrying 300lbs of additional stuff when comming back from Ohio.
Lets get these prices down.
Chris

 

[Yenick1]

My gas data

When I bought my GTP, I thought I would chart my gas usage and see how close it was actually to the DIC. I made a chart thats linked here...

http://people.msoe.edu/~oblamskn/GTP/Excel/Gas.htm

On the right are graphs of certain things. In 6/04 sometime i went from stock to 3.4 pulley, FWI, 180*° therm. The very bottom graph shows the error in the DIC...

Nick

 

[Guest]

But I would think it's safe to say that I wouldn't pay back the price for a Wizaired on gas mileage increase alone (assuming there is one) Although it sure keeps tempting me, that and maybe a 3" DP with a high flow cat . . .

 

[vertigo12369]

But I would think it's safe to say that I wouldn't pay back the price for a Wizaired on gas mileage increase alone . . .

Yeah, that's why I'm going to make my own It doesn't need a box and heat shielding over the winter, and by summer I'll have finished it...

 

[NismoMaxima]

air intakes and exhausts help an engine 'breath' better/easier.
blocking off the EGR and getting rid of your accessory belt helps too.

while in theory this does increase your mpg because your engine's efficency has been increased.
However the desire to hear your intake scream at redline kinda destroys one's mpg...

in the end the best way to increase mpg is weight loss. period.

 

[99GT2dr]

Actually, blocking off the EGR will decrease MPG. And as far as removing the accessory belt, i'm not sure about maximas or whatever, but on GP's you won't get very far without your water pump flowing coolant through the motor.

 

[NismoMaxima]

umm.... no.

how does not burning old used up air hurt mpg?

the egr is for emmisions.

why do most aftermarket headers eliminate the EGR?

i was simply simply mentioning 2 ways to increase mpg that hadn't been discused...