Vortex Generator increase mpg on RX7?
04-25-08, 10:19 AM
#1
Junior Member
Thread Starter
Join Date: Apr 2008
Location: Michigan
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Vortex Generator increase mpg on RX7?
Hey I am trying to increase my mpg on my 1980 RX7 and Im looking up some stuff on what I can do and I came across vortex generators. Does anyone know if they work well on an RX7 or if they are even safe to put in your car? I was thinking about trying it but I kinda want to get some better info on it. They say it can increase your mpg by 31%. If this doesn't work then what else can you do to increase the mpg besides the way you drive it? What could I do to the engine. I got a tune up on it and it's already like night and day the way it runs. 
04-25-08, 11:04 AM
#4
"Vortex Generators" are complete BS.
I'll have to search it up later when I have more time but there was a great thread around here somewhere that went into great detail about how completely bunk those things are.
As for increasing your gas mileage, unfortunately there is not much you can do. If your car is tuned up and running well, the most you'll ever get is stock mileage. Even that is next to impossible because that was measured with an engine that doesn't have probably close to 200,000km on it.
Honestly if you're looking for gas mileage, go pick up a civic. I'm not trying to be rude, so don't take it that way, but the rx7 is a sports car and if you're driving one then gas mileage should not be the first thing on your mind.
To give you an idea, doing 100% highway I get gas mileage just a little worse than my Sunfire gets in the city. In the city, I get about 400km/tank sometimes a bit less if I'm stepping on it often.
To me, this is the price I pay for owning my car.
The -original- gas mileage for the car was listed at
http://www.geocities.com/MotorCity/S...tgen.html#1984
The SA (79-80) is listed around
17mpg City / 26mpg Highway
And an S3 FB (84-85) is around
21 City / 30 Highway (Non GSL-SE)
I don't know what those mean in terms of my car because I do all my calculations in in Litres and Kilometres, so you'll just have to figure out how you're doing but those numbers are what you'd have if your engine and everything was brand new.
Jon
I'll have to search it up later when I have more time but there was a great thread around here somewhere that went into great detail about how completely bunk those things are.
As for increasing your gas mileage, unfortunately there is not much you can do. If your car is tuned up and running well, the most you'll ever get is stock mileage. Even that is next to impossible because that was measured with an engine that doesn't have probably close to 200,000km on it.
Honestly if you're looking for gas mileage, go pick up a civic. I'm not trying to be rude, so don't take it that way, but the rx7 is a sports car and if you're driving one then gas mileage should not be the first thing on your mind.
To give you an idea, doing 100% highway I get gas mileage just a little worse than my Sunfire gets in the city. In the city, I get about 400km/tank sometimes a bit less if I'm stepping on it often.
To me, this is the price I pay for owning my car.
The -original- gas mileage for the car was listed at
http://www.geocities.com/MotorCity/S...tgen.html#1984
The SA (79-80) is listed around
17mpg City / 26mpg Highway
And an S3 FB (84-85) is around
21 City / 30 Highway (Non GSL-SE)
I don't know what those mean in terms of my car because I do all my calculations in in Litres and Kilometres, so you'll just have to figure out how you're doing but those numbers are what you'd have if your engine and everything was brand new.
Jon
Last edited by vipernicus42; 04-25-08 at 11:10 AM.
04-25-08, 11:15 AM
#5
Junior Member
Thread Starter
Join Date: Apr 2008
Location: Michigan
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
mpg wasnt on my mind with this car until I started paying almost $4 a gallon for it. I would pick up a civic if I had the money to do it. I think I get around 20mpg right now. I was driving a cadillac STS during the winter, cost me $70 to fill the tank getting 18mpg and my RX7 costs $40 to fill it and I get about the same amount of miles out of the tank so I know it gets better mpg than the caddi but if there is any way possible to tweak it up then i would rather do that than buy a whole new car.
04-25-08, 11:26 AM
#7
djessence
Man, only $4. Consider yourself lucky. If you do the conversions etc some of the cheaper gas in canada is 4.50USD per gallon.
Just make sure everything on your car is in good working condition and thats about all you can do.
Just make sure everything on your car is in good working condition and thats about all you can do.
Trending Topics
04-25-08, 11:27 AM
#8
Yeah, so with 175,000km on your engine it's pretty far into its life. Even if it's been perfectly cared for, your engine is probably running compression like mine (about 7.2kg/cm2 instead of the 9ish it runs stock or on a fresh rebuild). Even a perfectly cared for engine wears, it just wears evenly and a bit more slowly.
Mine's stored every winter, driven every summer as well, it sounds like you have a nice car there.
If you're getting 20mpg city you're doing very well for yourself since that's almost stock mileage!
Jon
Mine's stored every winter, driven every summer as well, it sounds like you have a nice car there.
If you're getting 20mpg city you're doing very well for yourself since that's almost stock mileage!
Jon
04-25-08, 11:29 AM
#9
Do the conversion and you get
$1.25 * 3.785L = $4.73 per gallon
I'm not going to bother with currency exchange since we're about on Par right now, but that's what I'm paying at the pump and I'm definitely not getting stock mileage. My Sterling and RB exhaust make damn sure of that
Jon
04-25-08, 12:50 PM
#12
You'll have to search for it, but there's a way to modify it so that you can fire a 2nd gen ignition coil in a wasted spark setup. It isn't just a "bolt in" swap, so you'll have to read up on it until you're comfortable enough with the idea to try it.
Search for "2GDFIS" and you should end up with some info
Jon
Search for "2GDFIS" and you should end up with some info
Jon
04-25-08, 01:00 PM
#14
Waffles - hmmm good
iTrader: (1)
Vortex == gimmick, don't waste your money on it.
I would do the following:
1. Convert to an electric fan
2. Change over to the 2GDFIS (2nd gen coil)
3. Make sure the car is tuned correctly.
4. Keep the air up in the tires.
If your at 20 mpg now that should get you near 25mpg. I run all that plus a Dellorto and RE street exhaust setup and I get 25 mpg cruising ~70 mph in 5th gear. Goes down to 23 or so if I cruise ~80 mph.
I would do the following:
1. Convert to an electric fan
2. Change over to the 2GDFIS (2nd gen coil)
3. Make sure the car is tuned correctly.
4. Keep the air up in the tires.
If your at 20 mpg now that should get you near 25mpg. I run all that plus a Dellorto and RE street exhaust setup and I get 25 mpg cruising ~70 mph in 5th gear. Goes down to 23 or so if I cruise ~80 mph.
Last edited by t_g_farrell; 04-25-08 at 01:10 PM.
04-25-08, 01:12 PM
#15
Most things that increase performance will increase MPG. Free flowing exhaust/header and intake/air filter will help.
The problem with those mods is that the car becomes that much more fun to rev the **** out of it and your MPG goes down.
Buy a scooter if you want to travel cheaply.
The problem with those mods is that the car becomes that much more fun to rev the **** out of it and your MPG goes down.
Buy a scooter if you want to travel cheaply.
04-25-08, 05:53 PM
#16
I agree with all of this.
Would add when you do the coil upgrade to use the 2nd gen plugs. This is only for the leading side, use the standard plugs for the trailing.
Also recommend replacing the stock paper air filter element with the KN drop in.
Make sure the front end is in alignment.
I inflate my tires 5 PSI over the recommended pressures listed in the door jam or owners manual.
Use either 5w 30 or 10w 30 oil.
If you do not have emission testing in your area then the largest gain mileage wise would be to get a RB header system,
https://www.rx7club.com/showthread.ph...hlight=mileage
https://www.rx7club.com/showthread.p...ghlight=peejay
Would add when you do the coil upgrade to use the 2nd gen plugs. This is only for the leading side, use the standard plugs for the trailing.
Also recommend replacing the stock paper air filter element with the KN drop in.
Make sure the front end is in alignment.
I inflate my tires 5 PSI over the recommended pressures listed in the door jam or owners manual.
Use either 5w 30 or 10w 30 oil.
If you do not have emission testing in your area then the largest gain mileage wise would be to get a RB header system,
https://www.rx7club.com/showthread.ph...hlight=mileage
https://www.rx7club.com/showthread.p...ghlight=peejay
Vortex == gimmick, don't waste your money on it.
I would do the following:
1. Convert to an electric fan
2. Change over to the 2GDFIS (2nd gen coil)
3. Make sure the car is tuned correctly.
4. Keep the air up in the tires.
If your at 20 mpg now that should get you near 25mpg. I run all that plus a Dellorto and RE street exhaust setup and I get 25 mpg cruising ~70 mph in 5th gear. Goes down to 23 or so if I cruise ~80 mph.
I would do the following:
1. Convert to an electric fan
2. Change over to the 2GDFIS (2nd gen coil)
3. Make sure the car is tuned correctly.
4. Keep the air up in the tires.
If your at 20 mpg now that should get you near 25mpg. I run all that plus a Dellorto and RE street exhaust setup and I get 25 mpg cruising ~70 mph in 5th gear. Goes down to 23 or so if I cruise ~80 mph.
04-25-08, 10:41 PM
#19
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,761
Received 2,556 Likes
on
1,819 Posts
freeway my old gsl-se would get 26ish, the 79 got 25 once, more like 23 the rest of the time... you can get a little more but to make a big improvement, you need something like a non cali VX civic. something that runs way lean on a teeny engine, and is light.
04-26-08, 09:13 PM
#23
If you were referring to the Vortex being a waste of money, I agree. :-)
If you were referring to doing the mods to the car then see below.
I am going to disagree that it is a waste of money to do some of the listed things.
Example-
On my Se I bought a used Fiero electric fan from the wrecking yard for $20.00.
I tested my mileage with the stock fan set up and then with the electric fan.
Same distance, same speeds, etc........ (This was all highway testing)
Increase was 1 MPG
I did a test with the stock coil set up versus the 2nd gen one.
Did this twice driving the same distance (Highway).
Mileage was an average of 2.5 MPG better with the 2nd gen VS the stock coil set up.
Again got the Coil set up from the wrecking yard for $20.00
So for $40.00 I got an average of 3.5 MPG
The testing was done with a RB header/Pre-silencer system so I don't know what the gains would be running a stock exhaust system.
Overall with all the mods including the things that I mentioned plus the usage of a S4 N/A transmission out of an 88 model with the best overdrive. Using Acetone in the fuel I have managed to get a best of 31 MPG on the highway and average about 25-26 MPG combination driving.
Thats a 7 MPG increase on the highway and an average of 8-9 MPG increase with combined driving.
It also helps that I am at a higher altitude and the elevation ranges from 3600 -
4200 ft.
Peejay's report in the thread link that I provided with his low gears, ignition timing tweaks etc, has been getting extremely good mileage.
My last run this week consisting of speeds from 45MPH (8-9 miles), Average speed of 70 MPH (150 miles) with 2 short runs of non mentionable speeds (remote area).
52 miles of in town driving and speeds from 25-45 MPH the MPG was 25.3.
My test before that of 300 miles. consisting of combination of City and Highway driving, speeds from 35-65 MPH the mileage was 27.6 MPG.
If you were referring to doing the mods to the car then see below.
I am going to disagree that it is a waste of money to do some of the listed things.
Example-
On my Se I bought a used Fiero electric fan from the wrecking yard for $20.00.
I tested my mileage with the stock fan set up and then with the electric fan.
Same distance, same speeds, etc........ (This was all highway testing)
Increase was 1 MPG
I did a test with the stock coil set up versus the 2nd gen one.
Did this twice driving the same distance (Highway).
Mileage was an average of 2.5 MPG better with the 2nd gen VS the stock coil set up.
Again got the Coil set up from the wrecking yard for $20.00
So for $40.00 I got an average of 3.5 MPG
The testing was done with a RB header/Pre-silencer system so I don't know what the gains would be running a stock exhaust system.
Overall with all the mods including the things that I mentioned plus the usage of a S4 N/A transmission out of an 88 model with the best overdrive. Using Acetone in the fuel I have managed to get a best of 31 MPG on the highway and average about 25-26 MPG combination driving.
Thats a 7 MPG increase on the highway and an average of 8-9 MPG increase with combined driving.
It also helps that I am at a higher altitude and the elevation ranges from 3600 -
4200 ft.
Peejay's report in the thread link that I provided with his low gears, ignition timing tweaks etc, has been getting extremely good mileage.
My last run this week consisting of speeds from 45MPH (8-9 miles), Average speed of 70 MPH (150 miles) with 2 short runs of non mentionable speeds (remote area).
52 miles of in town driving and speeds from 25-45 MPH the MPG was 25.3.
My test before that of 300 miles. consisting of combination of City and Highway driving, speeds from 35-65 MPH the mileage was 27.6 MPG.
Last edited by Rx-7Doctor; 04-26-08 at 10:25 PM.
04-26-08, 10:41 PM
#24
i was referring to the vortex generator, not to your mods. I should have been a little bit more specific, but my brain is fried from working on take home, essay-based finals all day.
On a side note, here are some of my mods on my old '82, and the only time I ever checked for long-distance fuel economy, I got 24mpg with quite a bit of screwing around, plus a spare trans and a ton of tools in the hatch. I had:
RB SP exhaust
RB Holley 465
MSD Coils
E-fan
double pulley
no p/s, no a/c
Holley Blue pump w/ FPR tuned to 6psi
-6 lines (no return system)
cruising between 75 and 85, with short bursts to ??? (don't know because it's an '82), and the bursts were to shut down cavilers/focuses/6cyl auto mustangs that kept on trying to pass me on the right. 5-3 downshift opens up the secondaries nicely, but the secondaries wouldn't open back up after the shift to 4th (hence, my high rpm misses/lean condition and subsiquent blown engine)
On a side note, here are some of my mods on my old '82, and the only time I ever checked for long-distance fuel economy, I got 24mpg with quite a bit of screwing around, plus a spare trans and a ton of tools in the hatch. I had:
RB SP exhaust
RB Holley 465
MSD Coils
E-fan
double pulley
no p/s, no a/c
Holley Blue pump w/ FPR tuned to 6psi
-6 lines (no return system)
cruising between 75 and 85, with short bursts to ??? (don't know because it's an '82), and the bursts were to shut down cavilers/focuses/6cyl auto mustangs that kept on trying to pass me on the right. 5-3 downshift opens up the secondaries nicely, but the secondaries wouldn't open back up after the shift to 4th (hence, my high rpm misses/lean condition and subsiquent blown engine)
If you were referring to the Vortex being a waste of money, I agree. :-)
If you were referring to doing the mods to the car then see below.
I am going to disagree that it is a waste of money to do some of the listed things.
Example-
On my Se I bought a used Fiero electric fan from the wrecking yard for $20.00.
I tested my mileage with the stock fan set up and then with the electric fan.
Same distance, same speeds, etc........ (This was all highway testing)
Increase was 1 MPG
I did a test with the stock coil set up versus the 2nd gen one.
Did this twice driving the same distance (Highway).
Mileage was an average of 2.5 MPG better with the 2nd gen VS the stock coil set up.
Again got the Coil set up from the wrecking yard for $20.00
So for $40.00 I got an average of 3.5 MPG
The testing was done with a RB header/Pre-silencer system so I don't know what the gains would be running a stock exhaust system.
Overall with all the mods including the things that I mentioned plus the usage of a S4 N/A transmission out of an 88 model with the best overdrive. Using Acetone in the fuel I have managed to get a best of 31 MPG on the highway and average about 25-26 MPG combination driving.
Thats a 7 MPG increase on the highway and an average of 8-9 MPG increase with combined driving.
It also helps that I am at a higher altitude and the elevation ranges from 3600 -
4200 ft.
Peejay's report in the thread link that I provided with his low gears, ignition timing tweaks etc, has been getting extremely good mileage.
My last run this week consisting of speeds from 45MPH (8-9 miles), Average speed of 70 MPH (150 miles) with 2 short runs of non mentionable speeds (remote area).
52 miles of in town driving and speeds from 25-45 MPH the MPG was 25.3.
My test before that of 300 miles. consisting of combination of City and Highway driving, speeds from 35-65 MPH the mileage was 27.6 MPG.
If you were referring to doing the mods to the car then see below.
I am going to disagree that it is a waste of money to do some of the listed things.
Example-
On my Se I bought a used Fiero electric fan from the wrecking yard for $20.00.
I tested my mileage with the stock fan set up and then with the electric fan.
Same distance, same speeds, etc........ (This was all highway testing)
Increase was 1 MPG
I did a test with the stock coil set up versus the 2nd gen one.
Did this twice driving the same distance (Highway).
Mileage was an average of 2.5 MPG better with the 2nd gen VS the stock coil set up.
Again got the Coil set up from the wrecking yard for $20.00
So for $40.00 I got an average of 3.5 MPG
The testing was done with a RB header/Pre-silencer system so I don't know what the gains would be running a stock exhaust system.
Overall with all the mods including the things that I mentioned plus the usage of a S4 N/A transmission out of an 88 model with the best overdrive. Using Acetone in the fuel I have managed to get a best of 31 MPG on the highway and average about 25-26 MPG combination driving.
Thats a 7 MPG increase on the highway and an average of 8-9 MPG increase with combined driving.
It also helps that I am at a higher altitude and the elevation ranges from 3600 -
4200 ft.
Peejay's report in the thread link that I provided with his low gears, ignition timing tweaks etc, has been getting extremely good mileage.
My last run this week consisting of speeds from 45MPH (8-9 miles), Average speed of 70 MPH (150 miles) with 2 short runs of non mentionable speeds (remote area).
52 miles of in town driving and speeds from 25-45 MPH the MPG was 25.3.
My test before that of 300 miles. consisting of combination of City and Highway driving, speeds from 35-65 MPH the mileage was 27.6 MPG.
