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Improved Gas Mileage AND improved performance? by zzzhuh
Started on: 06-30-2014 09:49 PM
Replies: 158 (2293 views)
Last post by: zzzhuh on 07-18-2014 05:08 PM
zzzhuh
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Report this Post06-30-2014 09:49 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
Something that everyone seems to over look a lot is the type of gas we put in our car's. Having experience working at a gas station I have learned a lot about different octanes,and how they are diluted with Ethanol. It seems like every gas station now a days only has gas with either a %10 or %15 Ethanol dilution.

So why am I typing all of this when this doesn't concern fiero's?

Well, I have always been using shell premium 'V-Power' 91 octane gas on in my fiero. The gas seemed to run better and the performance was pretty good. I use my fiero as a commuter and am averaging a healthy 27MPG with a 4 speed muncie.

HOWEVER, I found a local gas station that advertises 91 octane fuel without ethanol in it. I looked into the difference between regular gas and gas cut with Ethanol and figured I would give it a try.

The first thing I noticed was that this 91 pure gasoline was $4.69 per gallon. That is a whole dollar more than the 91 octane I was getting at the shell. So I filled up, drove off and something amazing happened. My car seemed to have such a happier throttle response.

Going from 1st to 2nd was such a thrill and it seemed like my car was acting like it was brand new. Even in 3rd gear the car stilled seemed confident in giving me some good torque when I wanted it.

The gas mileage has improved in ways I figured was a joke. The average 27 MPG has now bumped up to an even 30. on a 10 gallon tank that is an extra 30miles I am getting back for spending $1 more.

I HIGHLY recommend trying out 91 octane no additives and test out the difference for yourself. I had no idea that simply using higher quality gas could deliver such a difference in performance.

Let me know what your experience is.


------------------
The wetter the better

[This message has been edited by zzzhuh (edited 06-30-2014).]

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Report this Post07-01-2014 01:40 AM Click Here to See the Profile for GodSendClick Here to Email GodSendSend a Private Message to GodSendEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:


The gas mileage has improved in ways I figured was a joke. The average 27 MPG has now bumped up to an even 30. on a 10 gallon tank that is an extra 30miles I am getting back for spending $1 more.



A dollar more per gallon? So 10$ more per tank.
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Report this Post07-01-2014 02:44 AM Click Here to See the Profile for PaulJKSend a Private Message to PaulJKEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:

Something that everyone seems to over look a lot is the type of gas we put in our car's. Having experience working at a gas station I have learned a lot about different octanes,and how they are diluted with Ethanol. It seems like every gas station now a days only has gas with either a %10 or %15 Ethanol dilution.

Let me know what your experience is.



i always use 91 octane in my cars. For me, Chevron seems to give me better power, Shell gives me better gas mileage. Don't know about anywhere else, but around here Chevron is always pure gas, but sometimes the Shell stations have the ethanol blend. i look all over the pumps for labels, and don't use the ethanol unless i'm almost out of gas - even then, I'll only put in enough to get me to a station with "real" gas.

Read up on the ethanol blended gas - from what i've read, it will gunk up your engine.
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Report this Post07-01-2014 02:47 AM Click Here to See the Profile for PaulJKSend a Private Message to PaulJKEdit/Delete MessageReply w/QuoteDirect Link to This Post

PaulJK

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quote
Originally posted by zzzhuh:

The first thing I noticed was that this 91 pure gasoline was $4.69 per gallon. That is a whole dollar more than the 91 octane I was getting at the shell.



In california, $4.69 for 91 Chevron is only about 20 cents more than 91 Shell
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Report this Post07-01-2014 07:28 AM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
I don't know of any stations in my area that even offer ethanol free gas
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Report this Post07-01-2014 07:49 AM Click Here to See the Profile for TONY_CSend a Private Message to TONY_CEdit/Delete MessageReply w/QuoteDirect Link to This Post
Assuming a ten gallon tank.....If you spend $4.69 for 91 octane without ethanol and get 30 mpg that is 15.6 cents per mile.
$3.69 for 91 with ethanol and 27 mpg is 13.6 cents per mile
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Report this Post07-01-2014 08:20 AM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Most vehicles don't require high octane fuel unless engine compression is more than 9:1, the vehicle is used for heavy loads or possibly for lots of stop and go traffic where the load is translated to acceleration from traffic lights, stop signs or rush hour traffic. Regular grade gasoline gives the best bang for the buck at highway cruising speeds. That's assuming that the engine is properly tuned.

With a 10 gallon tank, assuming 8 gallons of useable fuel, $8 for an extra 24 miles, not 30, comes up to an additional cost of $0.33 cents per mile. I do believe that most brands of premium fuel do not have ethanol added, and the price spread between 87 octane regular and the premium grade is usually less than $1 per gallon. Maybe it's just the difference between the other brand and Shell?
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Report this Post07-01-2014 08:27 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
I agree I'd love to run straight gas, it can however become a hinderance to the wallet. I do use ethanol free sometimes and especially when I will be storing the car for winter, it stays fresh longer. I always use ethanol free in small engines.

In my location ethanol free is 91 and says recreational use only on the pump. In Wisconsin, Illinois and Iowa I noticed they have ethanol free 87 octane at alot of pumps.
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Report this Post07-01-2014 08:31 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post

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quote
Originally posted by fierofool:

I do believe that most brands of premium fuel do not have ethanol added


In our state they almost all do, and are specifically marked no ethanol if they do not. I asked a few station owners 3-4 years ago and they said they did not sell anything ethanol free. Those stations had 87, 89 and 91 octane. Now however there seem to be more of the "recreational gas" pumps popping up.
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Report this Post07-01-2014 09:24 AM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Csjag:

I don't know of any stations in my area that even offer ethanol free gas


I thought the exact same thing but I was able to find a website that helped me locate a gas station that offer's the ethanol free gas. You have to scroll towards the bottom and select your state. Here is the link:

http://pure-gas.org/
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Report this Post07-01-2014 09:32 AM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by TONY_C:

Assuming a ten gallon tank.....If you spend $4.69 for 91 octane without ethanol and get 30 mpg that is 15.6 cents per mile.
$3.69 for 91 with ethanol and 27 mpg is 13.6 cents per mile


My 30MPG average does consist of me hot rodding it from stop light to stop light. If I didnt have such a heavy foot I could probably get at least 35 MPG (which is pretty good considering the car is almost 30 years old).

The price to me seems small considering on how much healthier the gas is for our car's. PaulJK mentioned that ethanol blended gas can gunk up your engine. While it does have that possibility with poor maintenance, think about how our car's were designed back when they were new. Ethanol gas didn't exist then so our car's engines were designed to run on pure gas. I know that my brother's 68 Buick GSX act's very strange on Ethanol gas compared to pure gas, and my 86' GT just seems more 'alive' on the 91 pure.

[This message has been edited by zzzhuh (edited 07-01-2014).]

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Report this Post07-01-2014 09:48 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Csjag:
I don't know of any stations in my area that even offer ethanol free gas

Yes, Most/All State in US have 10% or less ethanol content.
Why? Short Version.
EPA force most states to use reformulated gas with MTBE or Ethanol. MTBE was cheap and can be push thru oil/gas pipeline.
EPA "Ban" MTBE by eliminated law suit shield to protect oil co's. MTBE clean the air but very small amounts can pollute a huge area water, including aquifers.
EPA still required states to use reformulated gas but with only Ethanol.
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Report this Post07-01-2014 10:00 AM Click Here to See the Profile for darkhorizonSend a Private Message to darkhorizonEdit/Delete MessageReply w/QuoteDirect Link to This Post
10% ethonol is invisible to your motor.

You will get better mpg due to increased btu content but not much more than 2 or 3% better. The rest is just placebo effect.
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Report this Post07-01-2014 10:21 AM Click Here to See the Profile for Old LarSend a Private Message to Old LarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Your car, your wallet. I've run 85 octane (in Colorado), I've run 86, 87, 89, 91, 93 octane, pure gas and have never seen any big difference in mpg. I biggest effect on mpg is your right foot.
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Report this Post07-01-2014 10:51 AM Click Here to See the Profile for NetCamClick Here to visit NetCam's HomePageSend a Private Message to NetCamEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:


I thought the exact same thing but I was able to find a website that helped me locate a gas station that offer's the ethanol free gas. You have to scroll towards the bottom and select your state. Here is the link:

http://pure-gas.org/


Looks like I've been running ethanol free since I went to the 3800sc, the premium gas at my station is pure gas.
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Report this Post07-01-2014 11:06 AM Click Here to See the Profile for olejoedadClick Here to Email olejoedadSend a Private Message to olejoedadEdit/Delete MessageReply w/QuoteDirect Link to This Post
35 mpg with a v6 4 speed would be uncommon....
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Report this Post07-01-2014 01:53 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
What size tires are on your car?

Seems like maybe you are running undersize tires or your speedo gear needs replaced or something.
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Report this Post07-01-2014 01:57 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

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quote
Originally posted by olejoedad:

35 mpg with a v6 4 speed would be uncommon....


30 MPG would be uncommon. Maybe keeping at 55 MPG at 100% highway driving it could be done, but I don't buy it for a "daily commute" with stop lights and, "hot rodding light to light" as part of one's driving. Someone is calculating it wrong, or the measurements are way off.
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Report this Post07-01-2014 02:02 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

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quote
Originally posted by zzzhuh:
The price to me seems small considering on how much healthier the gas is for our car's. PaulJK mentioned that ethanol blended gas can gunk up your engine. While it does have that possibility with poor maintenance, think about how our car's were designed back when they were new. Ethanol gas didn't exist then so our car's engines were designed to run on pure gas. I know that my brother's 68 Buick GSX act's very strange on Ethanol gas compared to pure gas, and my 86' GT just seems more 'alive' on the 91 pure.


The Fiero V6 was built to run on 85 octane, not 91. Unless you've advanced the timing a whole lot, increased the compression a bunch, or are running a turbo, then 91+ octane is a waste of money. Also, ethanol-blended gas has been around in the US since the 70s. It was certainly around when the Fiero engines were designed and built.
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Report this Post07-01-2014 03:47 PM Click Here to See the Profile for PonnariSend a Private Message to PonnariEdit/Delete MessageReply w/QuoteDirect Link to This Post
You are right on dobey! My stock 86 GT runs better and gets better millage on low or mid grade than it does on premium! get 28-30mpg city, 31-32 freeway. That's not putting my foot in it though.
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Report this Post07-01-2014 06:01 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by olejoedad:

35 mpg with a v6 4 speed would be uncommon....


I thought the same thing but I swear my 86GT is a one of a kind. I figured the 5 speed would get even better MPG but my 4 speed seems to give em a run for their money. I guess the secret is Mobil 1 full synthetic high mileage oil and 91 octane
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Report this Post07-01-2014 06:10 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


The Fiero V6 was built to run on 85 octane, not 91. Unless you've advanced the timing a whole lot, increased the compression a bunch, or are running a turbo, then 91+ octane is a waste of money. Also, ethanol-blended gas has been around in the US since the 70s. It was certainly around when the Fiero engines were designed and built.


Your right the fiero doesn't require 91 octane like my 91' Seville does. From personal experience I have seen car's start to loose power and life when 85 is used when 91 is recommended. I did mistakenly say that ethanol wasn't made when clearly it was. Henry Ford actually designed the first model T to run off of just ethanol fuel. Makes me wonder why car designer's don't just make car's run off of that, maybe it has something to do with personal profit?

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Report this Post07-01-2014 06:12 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post

zzzhuh

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quote
Originally posted by dobey:


30 MPG would be uncommon. Maybe keeping at 55 MPG at 100% highway driving it could be done, but I don't buy it for a "daily commute" with stop lights and, "hot rodding light to light" as part of one's driving. Someone is calculating it wrong, or the measurements are way off.


30MPG really isn't that uncommon. My car seems to enjoy being pushed every once and awhile. In fact, it seems to help improve the car's performance and gas mileage after driving it hard for a little bit.
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zzzhuh

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quote
Originally posted by NetCam:


Looks like I've been running ethanol free since I went to the 3800sc, the premium gas at my station is pure gas.


If it's the series 2 engine than it is recommended you run 91 octane anyways. I think the series 1 required it as well but I know series 3 only required 87.
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Report this Post07-01-2014 06:40 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:
30MPG really isn't that uncommon. My car seems to enjoy being pushed every once and awhile. In fact, it seems to help improve the car's performance and gas mileage after driving it hard for a little bit.


So what size tires are you running? In a bone stock Fiero GT you should be getting about 19 MPG, unless your daily commute is mostly highway driving with no stop and go traffic. 50/50 driving should be around 24 MPG, and 100% highway should be around 27 MPG.
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Report this Post07-01-2014 06:45 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

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quote
Originally posted by zzzhuh:
If it's the series 2 engine than it is recommended you run 91 octane anyways. I think the series 1 required it as well but I know series 3 only required 87.


No. The NA engine required 87 octane, the SC engine required 91 octane.
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Report this Post07-01-2014 07:01 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes OE Fiero engine use 85 87 Octane. Many "Upgrade" engines too. You need to find Owners book for upgrades.
More/less Octane then engine requires often means less MPG.
Example for Less: You can run 85 on an engine requires 91 but knock sensor will likely go nuts and cut MPG as a result.

All Major, and some Minor, Brands are Top Tier fuels. Same Cleaning additives are in all grades.
Other Brands can use best cleaners only on premium grades or whatever.

See my Cave, Fuel & Knock

edit to fix typo

[This message has been edited by theogre (edited 07-02-2014).]

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Report this Post07-01-2014 07:56 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


No. The NA engine required 87 octane, the SC engine required 91 octane.


Right.... NetCam said "Looks like I've been running ethanol free since I went to the 3800SC."

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zzzhuh

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quote
Originally posted by dobey:


So what size tires are you running? In a bone stock Fiero GT you should be getting about 19 MPG, unless your daily commute is mostly highway driving with no stop and go traffic. 50/50 driving should be around 24 MPG, and 100% highway should be around 27 MPG.


I am on stock format tires, tho they seem to be more of a street tire more so than a all season tire (should probably change that.)

I am simply explaining my experience here, my fiero gets more than 19MPG in the city no matter how I drive it. The EPA rating is right around where you have stated but my car just seems to do better. Then again, these tests were probably on regular 85, thus concluding that higher octane IS helping my fuel economy, but like I said that's just my experience.
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zzzhuh

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BTW, I do have my tires filled up past 35PSI, im running em more around 40, seems to deliver a smoother ride.
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Report this Post07-01-2014 08:25 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:
I am on stock format tires, tho they seem to be more of a street tire more so than a all season tire (should probably change that.)

I am simply explaining my experience here, my fiero gets more than 19MPG in the city no matter how I drive it. The EPA rating is right around where you have stated but my car just seems to do better. Then again, these tests were probably on regular 85, thus concluding that higher octane IS helping my fuel economy, but like I said that's just my experience.


No. The numbers you stated are way off from what you should be getting. Either your doing the math wrong, or the measurements are wrong. There is no way you're getting 50% more MPG than the EPA estimates. If you're on stock sized tires, my guess would be that the speedo gear in the transmission, has a few missing teeth (the odometer isn't turning the correct amount).

Running premium gas in your car isn't going to give you better MPG or performance, unless you've got the necessary pre-existing mods to gain that MPG and performance, and they require higher octane fuel. Running higher than 87 octane in a stock Fiero is just a waste of money. Any perceived performance or MPG gain is either placebo effect, bad data, or something wrong with the engine or electrical system.

You need more timing and more compression to get a complete burn of higher octane fuels. Running higher octane fuel in a stock Fiero engine will not burn all the fuel that is put into the engine, which means it burns rich, can damage that catalytic converter, and you will get less MPG as a result.

Your converter could be going bad, and the excess unburned fuel from the 91 octane is causing the cat to heat up more than normal, and helping the engine out a bit. That could make it feel like you are gaining performance, when instead of buying more expensive gas, you should just replace the converter. That can also cause the O2 sensor to read rich, which might result in the ECM leaning out the mixture a bit, which might be perceived as increased MPG. But I guarantee you are not getting 30 MPG, or even 27 MPG, in stop and go traffic, with a stock 2.8 and the stock 4 speed manual.
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Report this Post07-01-2014 10:01 PM Click Here to See the Profile for zzzhuhSend a Private Message to zzzhuhEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


No. The numbers you stated are way off from what you should be getting. Either your doing the math wrong, or the measurements are wrong. There is no way you're getting 50% more MPG than the EPA estimates. If you're on stock sized tires, my guess would be that the speedo gear in the transmission, has a few missing teeth (the odometer isn't turning the correct amount).
.


Someone seems to enjoy arguing aye?

Everything in my car is operating properly. I reset my trip everytime I am filling up my car. I can go up to 250miles before I end up throwing about 8 gallons into my tank. If you ever stop by in Colorado, P.M. me and I will drive you to were you need to go. You can then tell ME how it is that im getting this type of gas mileage.

BTW, why would you automatically assume something is wrong in my car if I am getting BETTER than average gas mileage? That's like saying,

"I defeated cancer without going through chemotherapyo."

"Well there must be something wrong with your body then."

[This message has been edited by zzzhuh (edited 07-01-2014).]

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Report this Post07-01-2014 11:08 PM Click Here to See the Profile for fierofoolClick Here to visit fierofool's HomePageClick Here to Email fierofoolSend a Private Message to fierofoolEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is it possible a previous owner may have installed the economy 4-speed? I can say that my 2 85 GT's with stock 4-speed were up in the 27-29 mpg range when running on the interstates without using the AC. After the trans in each was replaced with Isuzu 5-speeds, my mpg actually dropped. My 87 GT with Getrag also only gets mid 20's and my 86 SE with Getrag is in the 20-22 mpg range.

With each of the Getrag equipped vehicles, I do find that I get better mpg when in the hills and never getting into 5th gear. I think it's because it's harder for the car to pull hills in 5th so you have to put your foot into it moreso than if in 4th gear.
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dobey
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Report this Post07-01-2014 11:22 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zzzhuh:


Someone seems to enjoy arguing aye?

Everything in my car is operating properly. I reset my trip everytime I am filling up my car. I can go up to 250miles before I end up throwing about 8 gallons into my tank. If you ever stop by in Colorado, P.M. me and I will drive you to were you need to go. You can then tell ME how it is that im getting this type of gas mileage.

BTW, why would you automatically assume something is wrong in my car if I am getting BETTER than average gas mileage? That's like saying,




Not arguing. Pointing out facts. No stock V6 Fiero gets 30 MPG city, especially not in the higher elevation in Colorado.

21 MPG is better than average mileage for a V6 Fiero. You claim to be getting 10 MPG more than that in the city; and that you drive it hard light-to-light, and you live in FoCo which is 5000 ft above sea level. Sorry to burst your bubble, but the data just doesn't add up.

At your elevation you should see slightly better MPG with a 100% correctly running and tuned engine, burning the correct fuel. If you switch to higher octane and see an increase in MPG, then that should be a sign that something is not totally correct with the car runs. First guess would be timing needs adjusted, and maybe your cat is going bad.

I'd also get your speedometer and odometer tested for accuracy. Seems like maybe the odometer is turning about 1.5x more miles than it should be. Or you are spending a lot more time on the freeway than you have suggested.
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dobey
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Report this Post07-01-2014 11:25 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post

dobey

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quote
Originally posted by fierofool:

Is it possible a previous owner may have installed the economy 4-speed? I can say that my 2 85 GT's with stock 4-speed were up in the 27-29 mpg range when running on the interstates without using the AC. After the trans in each was replaced with Isuzu 5-speeds, my mpg actually dropped. My 87 GT with Getrag also only gets mid 20's and my 86 SE with Getrag is in the 20-22 mpg range.

With each of the Getrag equipped vehicles, I do find that I get better mpg when in the hills and never getting into 5th gear. I think it's because it's harder for the car to pull hills in 5th so you have to put your foot into it moreso than if in 4th gear.


I got 28 MPG 99.9% highway (only getting off the highway for food/gas/rest stops), in my 87 GT w/Getrag, on a 15 hour drive from the East cost to the Midwest, going over/through the mountains, at 75-80 MPH pretty much the whole trip.
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2.5
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Report this Post07-02-2014 08:37 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
dobey I have never heard a cat going bad can help out an engine, how does it do this?
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Report this Post07-02-2014 09:06 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 2.5:

dobey I have never heard a cat going bad can help out an engine, how does it do this?


It doesn't. But, depending on how bad it is, it would be plausible for running higher octane fuel to give the impression of getting better MPG/performance from the higher octane fuel, as you don't get a complete burn, and the extra fuel going into the cat might get it hot enough again to seem like it's fine. Portions of the element inside the cat that may be creating blockage when cold, might separate enough to improve the flow, when it gets hot enough. This would really only happen in the earlier stages of the cat going bad though. Once the element breaks loose enough from the structure to block the exit more fully, or as bits break apart and get stuck further down in the exhaust, it's unlikely for this to happen.

Not likely to happen in general, but it is a plausible explanation for the 'I switched to 91 and got more MPG and performance out of the engine."

The only way to get close to a complete burn on 91 octane on a stock 2.8 is to run the engine way advanced, have a much more powerful ignition system, and a 0-gague ground strap. Not exactly a stock setup any more, but it would let you burn premium fuel much more efficiently than stock does.
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Report this Post07-02-2014 09:57 AM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
My Formula averages 26 mpg normally and 24 mpg with liberal use of A/C in mixed driving but leaning to mostly highway with occasional traffic... Stock size tires - 5 speed.

Edit mpg, not mph

[This message has been edited by lou_dias (edited 07-02-2014).]

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2.5
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Report this Post07-02-2014 09:59 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
I'd be curious what he gets with 87 octane ethanol free, comparitively. As I mentioned I have seen that in some states.
I used it in my 98 Saturn and achieved 4 more mpgs (over 10% eth) when measuring all hwy miles at 60 mph.
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Report this Post07-02-2014 03:03 PM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
2.5 I owned a lot of Saturn's in the 90's and went to two of their homecomings at the factory. Do you know if anyone has put the 1.9 twin cam in a Fiero, it a pretty light motor.
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