how to get 30+ mpg on a n/a rex
10-10-05, 11:36 PM
#3
Look ma'! I am spoolin'!
Join Date: Nov 2004
Location: california, San Luis Obispo
Posts: 747
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by DREYKO
any suggestions? im getting 15-18 mpg and i need more
But when I put my foot in to it, I get like 3 gallons to the mile.
10-10-05, 11:42 PM
#4
I "lost" my emissions....
Thread Starter
i keep seeing people on here claiming to get up to 35 mpg and i wanna find out what the hell theyre doing diff. i dont want to sacrifice power though
Trending Topics
10-11-05, 12:18 AM
#9
Lives on the Forum
Keep her at a constant cruising speed between 3 and 3.5k rpm on the highway for most of your drive and you should net between 27-30 mpg...
If you drive mostly city, give your quest up
If you drive mostly city, give your quest up
10-11-05, 12:24 AM
#10
People who claim to get 30+mpg in a rotary powered car are full of **** unless they're driving all highway, 55-60mph, flatland, drafting behind a truck, with a straight intake and exhaust and no emissions equipment, running a hot thermostat with a LEAN tune, 50psi of air pressure in the tires, synthetic drivetrain lubricants, acetone and premix in the tank.
You generally see 22-26 highway and 14-16 city out of an NA in good running condition.
Even if you can prove that some amount of mods plus tuning could attain better mileage, the COST of those mods and tuning would exceed the difference in gas you would possibly save for a very long time.
For instance...my yukon MIGHT get 2-3mpg better if I were to replace the 4 original 02 sensors at a cost of >$100 each. However, if I invest that $400-500, how long does it take me to earn my INITIAL COST back with the POSSIBLE 2-3mpg gain, not to mention how long before I start saving money?
You generally see 22-26 highway and 14-16 city out of an NA in good running condition.
Even if you can prove that some amount of mods plus tuning could attain better mileage, the COST of those mods and tuning would exceed the difference in gas you would possibly save for a very long time.
For instance...my yukon MIGHT get 2-3mpg better if I were to replace the 4 original 02 sensors at a cost of >$100 each. However, if I invest that $400-500, how long does it take me to earn my INITIAL COST back with the POSSIBLE 2-3mpg gain, not to mention how long before I start saving money?
10-11-05, 12:32 AM
#11
Displacement > Boost
Join Date: Oct 2002
Location: Mississippi
Posts: 3,503
Likes: 0
Received 0 Likes
on
0 Posts
All it took to get 26 in my NA base model was properly inflated tires, a cone intake filter, and a reasonably good state of running condition. This was mostly freeway at 70-75mph with a few miles of city driving (first time I drove it back from buying it). Stock ECU, nothing fancy as far as mods, just a cone air filter and 185 width tires properly inflated.
After doing some weight reduction, streetporting it and putting on a header and SAFC, filling the drivetrain with redline synthetic oil and setting a reasonably lean cruise tune, I got 27mpg on 205 width tires. *edit* (coming back from Seattle on the freeway, 75mph)
After doing some weight reduction, streetporting it and putting on a header and SAFC, filling the drivetrain with redline synthetic oil and setting a reasonably lean cruise tune, I got 27mpg on 205 width tires. *edit* (coming back from Seattle on the freeway, 75mph)
Last edited by 88IntegraLS; 10-11-05 at 12:39 AM.
10-11-05, 12:46 AM
#13
Over inflate the tires just a bit and install a taller 5th gear to lower the rpm's on the highway. That should help get closer. Gearing is the main reason Corvettes and other GM v8's get such great highway mileage. They have enough low end torque to accelerate the car at really low rpm's. My stock Fd got 26mpg last year on the highway while cruising at 75mph (3k rpm's) on my trip to sevenstock with a/c on. If I could have lowered the rpm's to maybe 2,500 at that speed, that could have maybe showed some improvement.
Last edited by t-von; 10-11-05 at 12:49 AM.
10-11-05, 01:17 AM
#14
I wish I was driving!
Originally Posted by RotaryResurrection
People who claim to get 30+mpg in a rotary powered car are full of **** unless they're driving all highway, 55-60mph, flatland, drafting behind a truck, with a straight intake and exhaust and no emissions equipment, running a hot thermostat with a LEAN tune, 50psi of air pressure in the tires, synthetic drivetrain lubricants, acetone and premix in the tank.
You generally see 22-26 highway and 14-16 city out of an NA in good running condition.
You generally see 22-26 highway and 14-16 city out of an NA in good running condition.
But... if you were trying to do this just to save money... its stupid. It costs several thousand dollars to get your car to that point.
What I do: Make the engine as efficient an air pump as possible... cone filter, full exhaust, engine porting.
Run 30 psi tire pressure, front and rear.
40 psi of fuel pressure.
Stock coolant thermostat, stock oil thermo.
Premix, 100:1.
Synthetics (RP or Neo) in the drivetrain, dino or synthetic in the engine.
Pull out fuel at cruise until it lean surges, and then back it just a hair. off. (need an aftermarket EMS). Typically, this is 15.8-16.5:1 AFR's.
Drive at 62-65mph.
No A/C on.
Highway fuel economy only.
So... you need a $2000 EMS and a $3000 engine to save a couple bucks in gas. Pretty dumb, unless you've already got the mods.
Stock ECU... 26-27 mpg and you should be very happy.
10-11-05, 01:51 AM
#15
Emerald Triangle for life
iTrader: (5)
Join Date: Jan 2002
Location: Fort Collins, CO
Posts: 552
Likes: 0
Received 0 Likes
on
0 Posts
I got 27mpg in a junkyard GXL with a cone filter, exhaust (with cat), mild weight reduction and a good tune-up. Total cost (at the time): $2500 including a $800 parts car. It might not be 30mpg, but it's close enough. 
10-11-05, 03:52 AM
#18
Rotary Power Information
Join Date: Aug 2003
Location: New Hampshire, Greenfield
Posts: 528
Likes: 0
Received 0 Likes
on
0 Posts
So... you need a $2000 EMS and a $3000 engine to save a couple bucks in gas. Pretty dumb, unless you've already got the mods.
10-11-05, 04:22 AM
#20
Super Raterhater
iTrader: (6)
Join Date: Dec 2001
Location: NY, MA, MI, OR, TX, and now LA or AZ!
Posts: 10,624
Likes: 0
Received 2 Likes
on
2 Posts
I've consistently got 30-32 in my GTUs. EGT's sit right around 800C at cruising though (I suspect there's some vac leaks that I've yet to find that are contributing to a lean condition), all it had was an intake with a box, full exhaust (no cats/etc), and only 3 vacuum lines. Best mileage was cruising through Ohio, got 33 on the freeway, through new york/pennsylvania it was right at 30 for freeway running between 75-80. City driving usually netted mid 20's, ~45mph roads, maybe at 20 miles each direction with about 7 stop signs along the way on average.
10-11-05, 05:26 AM
#22
Originally Posted by maffut
what exactly does running lean mean? does that mean running fuel tight, just enuff for the car to function?
10-11-05, 07:25 AM
#24
Lives on the Forum
You're not going to get over 30mpg unless you want to drive only on the freeways.
Is that what you're doing???
Getting 35mpg (or over that) is next to impossible, as Rotary Resurrection said.
If you want good gas mileage, get another car, period.
-Ted
Is that what you're doing???
Getting 35mpg (or over that) is next to impossible, as Rotary Resurrection said.
If you want good gas mileage, get another car, period.
-Ted