Exhaust for G-Street: Any benefit?

Discussion in 'Fiesta ST Autocross' started by CrookedRacer, Jul 28, 2014.

  1. CrookedRacer

    CrookedRacer Active Member

    So for a Nationals-style course, we're going to have to increase our power as best we can.

    Does anyone have any definitive numbers on what a cat-back exhaust can do for the power output of the FiST?

    Has anyone researched it such that I can be lazy and allow you to post your extensive research in a reply to this thread?

    I'd particularly like the numbers as they apply to 1st and 2nd gears. Correct me if I'm wrong, but we don't get all 197 horses until we hit 3rd gear, right? So does an exhaust help more or less so, compared to stock in 1st and 2nd gears?

    Just grasping at the last possible performance gains we might be able to squeeze out of this car for Nationals.

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  3. RodMoe

    RodMoe Well-Known Member

    If you are forced to run a stock tune you will not see any major benefit from a cat back other than the "Mental Horsepower" it gives from a sassy sound the big blockage is in the Downpipe and Cat on this lil car. Though you may be able to shave off some weight there is that ...
    I have seen and read a lot of claims but don't recall seeing any hard numbers.
  4. ryst

    ryst Active Member


    FSwerks claims 5 whp and 4 ft/lbs gains, but those kind of numbers are small enough that it could just be margin error from run to run. Also it's possible it's a custom tune with the CBE, but it doesn't say anything in the description.

    On the upside it's lighter than stock by 5 lbs.
  5. CrookedRacer

    CrookedRacer Active Member

    I think I could save a few hundred bucks and just buy P90-X in that case.
  6. moff3tt

    moff3tt Active Member

    I am planning a custom aluminium exhaust for mine. Should save significant weight over stock. Shouldn't be too much more expensive than a comparable custom stainless system either.
  7. djdennehy

    djdennehy Active Member

    Cat back exhaust and drop in air filter may release 5-10 horsepower, regardless of gear. We may think that a few horsepower won't make a major difference, and it won't... but if you have ever lost your class because you were a tenth or two off (as I have), you know that in autocross every little thing adds up...
    Mr UFO likes this.
  8. Cligedy

    Cligedy Active Member

    Fellow FiST'er at the Atlanta match tour told me that the Fswerks exhaust + Cobb green filter were good for about 10+hp for him. Not amazing, but worth doing
    djdennehy likes this.
  9. Mr UFO

    Mr UFO Active Member

    Have you drained your washer fluid? All floor mats out?
  10. CrookedRacer

    CrookedRacer Active Member

    I always take out the floor mats, rear headrests, cargo topper, cargo floor, spare, jack, spare mat, owners manuals, and sunglasses case.

    I try to vacuum the beagle hair off the back seat, but not so much for the weight savings: it tends to get whipped up into my face when I drive really fast with the windows open.

    I hadn't thought of emptying the washer fluid, but that's got me thinking. Maybe I could run the oil a quart low! And the coolant! And gear oil! Couldn't hurt, right? ;-)
    Mr UFO and djdennehy like this.
  11. djdennehy

    djdennehy Active Member

    The beagle hair delete option adds 5 horsepower...

    Seriously though, the more weight out the better. I didn't even think about pulling out the headrests, but that's a smart move. I would think that in removing the spare tire, jack, miscellaneous junk, head rests, lighter wheels, lighter exhaust we could potentially get the weight of the car down to 2600 something... every little bit helps at the track.
  12. Mr UFO

    Mr UFO Active Member

    I actually read in Grassroots Motorsports that the "hardcores" at the autox Nationals drain the washer fluid for weight savings. Thought it was hilarious but also ingenious!
  13. djdennehy

    djdennehy Active Member

    I wouldn't be surprised a bit to hear that. The amount of prep many go through on their car to dodge cones is fanatical, but it helps to make the sport fun.
  14. limbo

    limbo Active Member

    My no option FiST weighed in at 2620 lbs with 1/4 tank of fuel and no spare/tools/rear floor. If I could lose another 20 lbs from the exhaust <2600 is attainable even.

    How much do the headrests really weigh? I haven't pulled them out to see but I imagine they're pretty light?
  15. Cligedy

    Cligedy Active Member

    I don't even keep my rear headrests in the car. They conflict with the baby seat and reside in my garage. I also don't put them in just to autocross locally.

    That said, I actually wrote to the SCCA for clarification and they said that the headrests must stay in to be legal in Street class. It would take a real ass to protest missing headrests though, they weigh less than a pound each. However, according to my research, asses do sometimes autocross.
    djdennehy likes this.
  16. limbo

    limbo Active Member

  17. CrookedRacer

    CrookedRacer Active Member

    Headrests are pretty light (less than a pound each), so there isn't much to gain anyway. I guess I'll be leaving them in to be safe.

    My only question is: Did the SCCA clarification differentiate between occupants' (driver / passenger) headrests vs. empty rear seat headrests? You don't even need a tool to take the rears out. The fronts require a little screwdriver to release a tab somewhere, from what I've read.

    Next event, though, I'm spinning my front headrests around, since that's specifically allowed. I like an upright seat position and the headrest does interfere with my helmet.
  18. Cligedy

    Cligedy Active Member

    My question to the board was specifically about the rear headrests. I will just make sure to put mine back in before national events. I plan to do several next year.
  19. eRic

    eRic Active Member

    if you are making more horsepower than the guy in the next lane that is always a benefit. The FSWERKS exhaust weighs less than stock and makes more power. win-win. my Fiesta ST was 2608 lbs. with the spare tire and jack removed and about 1/4 tank of fuel on board.


    I autocross mine with the rear head restraints flipped down and the rear seats folded down to lower the center of gravity.
  20. eRic

    eRic Active Member

    yep. rules are rules. removing the rear head restraints is an illegal weight reduction. I have seen folks that run without washer fluid and some go as far as to bevel the leading edge of magnetic numbers to make them more aerodynamic. also I know folks that had a rule created to ban something that they did at Nationals the year before. there is a rule that says pop-up headlamps must be fully up or down, not halfway unless that can be achieved via the OE headlamp switch. folks would turn the knob to manually open one headlamp door halfway so that air could pass through into the air box that was located behind that headlamp. in Stock|Street you can only do so much... there are actually more things to do in Street vs. Stock since Stock did not allow wheel diameter changes or rear anti-sway bar changes.
  21. Mr UFO

    Mr UFO Active Member

    Stock wheels? I'm tracking Laguna Seca in a few weeks and I going to pull out the back seats too. Wondering if 2550 is realistic? I'm thinking yes!

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