chainzaw

FASS boasts of increased fuel efficiency. And after 8,000 miles with the 150/95-1008 complete system i haven't seen mpg gains once! I just wanted to ask you fellas to see if you have had better luck with their product than me. I'm starting to think that the claim is a bologna sandwitch aimed at suckers like me thinking "with mpg gains i can pay off this mod in no time!"
Yes I have it installed correctly, yes i have checked for fuel leaks hundreds of times.

Tate

I think with just about any mods we do, mileage claims should be taken with a grain of salt. The FASS is to supply constant, uninterupted fuel to the IP. Ideally, the stock LP would be doing this. I don't know where any milage gains would come other than the fuel being free of entrained air, and at a proper pressure.

chainzaw

Well my stock lp was giving me 6 psi at idle and 4 or 5 psi down the freeway and 0 under hard acceleration needless to say i was placing extra strain on the ip. So if the FASS can't give any noticeable mileage gains from near worst case scenario to brand new top of the line system i would say the claim is empty.

bullboy85

i saw some prittg good mpg gains... but i put it on cuz my filter houseing was leeking... so ya i did.

rebal

Zippo hear but I have a steady 16 psi thats why i bought it

cdennyb

It's totally bogus to think that if I have a stock pump providing 10 psi to my injector pump and get 15 mpg and buy a FASS system that provides the same injection pump with 20psi that I'm going to get better or worse mileage. It's all those mods you do that modify timing, injection fuel quanity, spray pattern enchancement or friction reduction that changes the mileage.

No dis-respect intended... use you brain and think this through.

ellerman

I didn't notice any mpg gains with mine but I did get a more responsive throttle. It's been on for about 80,000 miles. Eric

Dieseldude4x4

Nada. But my 44 is supposed to last longer.
CRAP, that's why I have been through three pumps in the last three years.
I think the Blue Chip did in one pump. Fuel pressure is real good though

chainzaw

I agree with you that simply changing the fuel pressure ain't going to help mpg gains. However i was led to believe that separating the air from the fuel would make a difference. By providing so called "test cell fuel" to the ip would make an improvement. But let me ask you a question. I'm i a fool for believing a promise? I guess so.

As soon as i installed my fp gauge i found that my lp was dieing. I didn't think i had 2-4 weeks to research and price new pumps. FASS seemed to be the popular choice at the moment, so i checked out the web site. It looked promising. I bought it. Now i find out the product isn't half that it is cracked up to be.

I just hate broken promises and that's the reason i posted this thread. I wanted to know if my system was a fluke or if FASS needs to get real with their customers.

I admit, i love the good pressure and long life filters.

chainzaw

anybody else? Over 200 people have viewed this thread.

madhat

Something that you have to take into consideration when you buy stuff like this.... trucks are different, just like people. For example, my edge does what the box claims, but on another guy's truck, it's not even close... dyno proven.

Have you called FASS yet? Maybe they can help you out.

If not, at least you have a good fuel pump.

If you don't like that answer, ask them if you can send it back!

TeamFASS

Hello Chainzaw,

Removing air/vapor from fuel has many benefits in which one of them can be fuel mileage. Many large corporations have recognized what negative affects air/vapor can have on the injection system components along with lost performance.

There are many variables to figuring fuel mileage, for example: idle time, traffic conditions, weather conditions, oil temperatures, tire pressures, driving habits just to name a few. It is difficult to isolate these conditions; this year we will be performing many more tests to get very accurate numbers.

On the conservative side most of the reports we receive back are 8% and more; usually between 1 – 3mpg for the pickups and .4 - .6mpg and up for the class 8 market. We have had some very wild claims but that is where I believe the variables are working with us. However, we make it very clear we do not guarantee fuel mileage; that is to risky due to all of the variables.

Removing air/vapor from fuel will help the life of injection system components along with improving engine performance and fuel mileage. Being able to recognize the fuel mileage improvements have a lot to do with the variables at play.

Brad Ekstam

Dracula

First tank with FASS I got worse mpg...but my foot was steadily in it .
Second tank was looking really good, then I hooked up to the trailer. Still got 15.7 (daily commuting) with 40 - 50 miles of that tank pulling the trailer. It does however seem to have better throttle response, but it could be my imagination.

Sunir

I didn't see any mpg improvements with my FASS 150/95-1008 setup. I didn't see any mpg improvements with 4" turbo back exhaust either, really come to think of it same deal with the intake...AND I noticed slightly WORSE mpg with my TC and VB. I'm not driving the truck any different than I did when it was bone stock, and i am a conservative driver.

To date the only thing I've seen which improved my mileage is the smarty set on a timing level. Other than that my truck has netted me better mpg's bone stock then it does now...used to fill up at 600 miles and now I fill at 550 miles still right around 27-28 gal per fill...and no it's not driving style, air pressure, traffic, this or that blah blah blah....this seems to be a consistant trend...I'll have to keep an eye on mileage over the summer and through this year hopefully see some improvements.

chainzaw

TeamFASS thanks for the post. I have tried to keep those variables you mentioned above in mind. And that is why i have waited to post after using the product for 8,000 miles. My driving habits, weather conditions, tire pressure, ect. change very little from week to week. I calculate my mpgs every tank and i honestly haven't seen an increase from before and after installing the FASS system.
Looking back at the people that have posted in this thread only bullboy85 clearly reported mgp gains, but then he did have a leaking filter housing which simply deleting could be the reason for the improvement.