Premix your 8, get better gas milage
 

Well I started premixing my 8 and noticed an improvement on gas milage. I am taking my numbers based on the 1/4 tank marks of the fuel level gauge.

Between all the tests I have not changed my driving style, have not been taking different driving routes, and have not experianced any traffic or long time idling periods that would make the numbers change.

Prior to premixing I was seeing on average about 50-53 miles per 1/4 and this was consistant through all the 1/4 tank marks and also mainly based on the 1/4-1/2 tank, 1/2-3/4 tank, and 3/4-full tank. I never ran the car empty enough to justify using the empty-1/4 tank for my numbers.

So essentially at each 1/4 mark I had traveled somewhere between 50-53 miles.

After premixing I am seeing 55-60 miles traveled per 1/4 tank of gas. This is equating to 15-20 more miles per tank of gas while premixing then then when not premixing.

So not only can premixing offer you increased apex seal lubrication but can also help on the gas milage. Others have also said that premixing will make your car idle a little smoother. Since my engine is pretty much new (~1400 miles) I really haven't noticed any difference in the idle.

Just thought I would share.

Jonathan

So what are you using in premix and how much?

With mine I notice I get about the same as you from full to 3/4 but from 3/4 to 1/2 I get about 75 miles. I can't really complain about gas mileage after I have heard some of the mileages people get. I drove to Tampa FL in Jan of 07 and averaged 24 to 25 miles to the gallon at 70 to 75mph average with the exception of the construction zones.

Premix wise I am using a walmart brand tc-3. Cost wise you can't beat it. I think when I went and picked some up I bought a gallon of it, a 16oz bottle of it (to use as the mesuring device) and a long necked funel and paid ~11 bucks for it all. I actually went with the walmart brand as Kevin made mention of it in another post and with 125K+ miles on his car I think its doing its job.

I mix 8oz per tank of gas.

I am going to run a couple of tanks where I am basing the findings straight off the odometer rather than the fuel gauge both with premixing and without just to verify that there is indeed a gain from premixing. Right now for example I am sitting just barly above a 1/4 tank of gas and the trip meter is reading 176.4 normally without the premixing it would be reading about 145-150 at this point. I don't think the fuel gauge would be reading over 25miles off but I will be doing the straight number calculations starting with my next fill up just to make sure.

Thanks! This is something I am going to look into getting and trying it out and see if I can see a difference! anything to help out on gas mileage! these days that is a must!

No kidding and from what I'm hearing its only going to get worse (price wise) over the next few months. :(

I might have to try this... as my MPG have dropped! I was averaging about 18-19 when I first got my 8 and now I'm avg. 15-17MPG. I know I drive fairly hard, but I say not much different than before..

I'm going to pick up a gallon of 2cycle and give it a shot this weekend.

Lets all give this a try and report:) I usually fill up my tank around 1/4 tank (160-190 Mile). Last night it took over 10 gallons fill to the top and I drove 155 miles.

Well I filled up this morning, it appears that I gained about 25miles/tank since premixing. I am going to keep actual numbers this time as far as odometer reading, gallons of gas bought, etc. I should have a more concrete number after 3-4 fillups and working the numbers out.

Worst case is your not increasing (or just barely) your MPG but the premixing can only help with seal lub so either way I think its a good route to go.

I have been using the Pettit racing premix for a while. My car feels like it idles smoother but I havent noticed a change in my mileage, but I dont pay attention to it in the first place.

Well I am going to try this and see how it works out!

Good news considering I'm starting to premix on my engine now as well.. I'll have to start calculating the difference in MPG too.


I'm curious why premixing gains MPG though... I would assume the PCM would manage most of that, is there something that would detect the additional level of oil in the fuel? What would create this change?

I'm curious myself as to why it might increase MPG. Don't have the answer there, I just know that I have increased my overal milage after premixing and my driving style or conditions have not changed between the non premixed tanks of gas vs the couple of premixed tanks I've run.

It would be interesting to see peoples various results between running it and not running it.

Well, my guess would be less

A) Less Friction
B) Better compression means more of the energy created from the combustion process is transferred to the rotation of the rotary rather than slipping past the seal
C) The oil burns more slowly than gas ensuring a longer, cleaner burn

Just filled my tank back up w/ some 2 stroke - we'll have to see what I get. Last full tank went 280 miles last go (all city, no real highway) so we'll see what we get this time w/ the same kind of driving.

WHAT 280 miles on a tank! Yikes!~! I get under 200 per tank in the city!

I just put 2 stroke and filled it up today.. We'll see what happens..

I pulled 325 miles out a tank with 6oz of RP TC-3. Granted it was all highway miles, but none the less that is still some great mileage!