No overboost in 1st or 2nd, respond with short tires?

Discussion in 'Fiesta ST Autocross' started by AlanBDahl, Nov 12, 2013.

  1. limbo

    limbo Active Member

    They fit well in test. No hard driving on them yet I took them out to breakfast and no rubbing.

    Specs are

    16x7 + 42


    Smokin and RodMoe like this.
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  3. Cligedy

    Cligedy Active Member

    That looks really good. I'm considering that exact setup. Do the 225s fit ok on the 7" wheel or can you feel them flex in turns?
  4. wash

    wash Active Member

    Now I'm thinking a 16*8" with the 225-50r16 BFG Rival might not be such a bad idea.

    I hope the sidewall won't take the edge off the handling.
  5. limbo

    limbo Active Member

    You'll get a little more 2nd gear which could be good. The Rivals have a pretty strong sidewall and on an 8 inch wheel I don't think you'd have any issue there.

    To Cligedy - The 225 Z2's on 7" do not feel pinched, I haven't pushed it enough to know if it can be felt.
  6. wash

    wash Active Member

    I thought I found a light 16*7.5 then I realized it was a 17*7.5" so I have a good option for the Direzza ZII 215-40r17 but I'm still looking for the right 16".

    I think eventually the wheel makers are going to start making suitable race wheels and tire manufacturers are going to make sizes that work well but it may take a while.
  7. AlanBDahl

    AlanBDahl Active Member

    The stock wheels are 7" wide, there appear to be a reasonable number of options for 17x7 and 16x7 wheels.
  8. ST_Rocky

    ST_Rocky Member

    Why does everyone want to go with a 45 series tire? Aren't the 40 series wider? And we all want as much tread on the pavement for the ultimate grip.
  9. stuntdoogie

    stuntdoogie Active Member

    45 or 40 series is is the sidewall height not the width.
  10. Couldahadav8

    Couldahadav8 Active Member

    For those who do not know, Mr. Dahl is a talented autocrosser. He knows his stuff. The lack of overboost in 1 and 2 explains the relatively slow 0-60 (along with the need for an extra shift). This does suck a bit for autocrossing. I still love my car so far. Funny, I was hoping to go to a taller tire so it could stretch 2nd to 61 or so. I had thought about going smaller given the potential benefit for gearing and center of gravity, but couldn't find a short 16-inch tire. This AM I did some more searching.

    Anyway, I looked at all the extreme performance tires out there (well except for the Nitto and Federal). These are the sizes with diameters.
    Tire Size Diameter
    Rival 245/45/17 24.7
    RE-11A 205/55/16 24.9
    215/45/17 24.7
    ZII 215/40/17 23.8
    215/45/17 24.7
    205/50/16 24.1
    205/55/16 24.9
    AD08R 215/40/17 23.7
    215/45/17 24.5
    RT-615k 205/40/16 22.5
    205/40/17 23.4
    Kooks 215/45/17 24.6
    205/55/16 24.9
    Ecsta XS 215/45/16 23.6
    215/45/17 24.6
    R1R 205/45/16 23.2
    205/50/16 24.3
    215/45/17 24.5
    Pilot SS 205/45/17 24.3
    205/40/18 24.5

    So, it looks like the R1R and RT615k are the tires with the smallest diameters available in a 16-inch wheel. The R1R is $146. The RT615k is $113. As far as I recall, the Falken is a tier down from the best tires. The R1R is difficult to judge given the variability in the tread compounds with that tire.

  11. AlanBDahl

    AlanBDahl Active Member

    Thanks for doing all the research! What size are the OEM tires? I'll have to plug the possible sizes into a calculator to see how they affect the 2nd gear speed (keeping in mind too that the redline drops after 3 seconds). I am thinking that I may need to change tires based both on course speed and air temp. Hopefully I can keep the options down two just two or the switch to street tires may cost me more money than the A6s did last year :-/. Thankfully compared to the $350 a tire I've been paying Fiesta tires are cheap though that's balanced by no more free tires from Hoosier.
  12. limbo

    limbo Active Member

    I am interested to see how the gearing will change. The R1R's seem like the only option for a significant drop in gearing without sacrificing a ton of grip.

    For anyone interested, the Sparco's with the 225/45/16 went great - no rubbing and lots of grip. More time in third gear would have been nice, though.
    Smokin likes this.
  13. wash

    wash Active Member

    I'm guessing that changing the final drive isn't an option?

    Stock is 3.8 something and it looks like there is a 4.07 and one even steeper than that.

    Its too bad that trying to go fast is going to make first gear kind of useless.
  14. eRic

    eRic Active Member

    changing the final drive is not legal in Stock|Street unless it was available as an option. So... we have the 3.82 in the Fiesta ST. The non-ST Fiesta comes with a 4.07 or 4.25 if you got the black sport appearance package.
  15. Couldahadav8

    Couldahadav8 Active Member

    OEM is 205/40/17 with a diameter of about 23.5 inches. I will be interested in your conversions as to how short of a tire you have to get to to make 3rd gear viable. IIRC, horsepower peak is at about 5200 rpm while torque peak is nice and low around 2700rpm.
  16. wash

    wash Active Member

    This is why I think the 1.0 could be the autocross weapon of choice.

    It probably won't have the boost limited in first and second, gearing probably better, 15" wheels, etc.

    All Ford needs to do is create a handling package with ST brakes and rear axle.

    If they sold that for around $18,000 lots of people would buy one, hop up the 1.0, install an inexpensive lowering spring kit, add wheels and tires and have a car that drives almost like an ST for under $20,000.

    Lots of people looking for a $16,000 car will be able to consider $18,000 while the $22,000+ for an ST scares away many.
  17. limbo

    limbo Active Member

    What makes you say better gearing? The higher final drive number doesn't mean anything since it's a 5 speed vs 6 speed.

    Sure boost won't be limited but it will still make less hp and torque in every gear.

    All those mods will put the car into at least an ST class. I could see it as a competitive option in stf or hs if that's where it gets classed but I'm not sure i would call it weapon of choice when you have to do all that work just to try to replicate what the ST already does.
    reddog99 likes this.
  18. eRic

    eRic Active Member

    Looking in dealer inventory on today you can buy a Fiesta ST for $20,695 and finance it for $287 month or lease for $187 month.
  19. wash

    wash Active Member

    If the 1.0 has full boost available in first and second, that's almost as much power as an ST, then you get class legal 15" wheels most likely and less weight, possibly classed with the base Fiesta.

    I think racers would like that as long as it has the ST brakes and rear axle because I think you can do coilovers even in stock class.

    For people that don't race, they could mod away and enjoy budget thrills on the street.

    Ford won't build something like that unless they can sell to more than just the competitive autocross racer, that's why it needs to be priced to up sell the $16,000 car market.
  20. limbo

    limbo Active Member

    Power is still down over 30% and I'd wager there isn't opportunity for much more with mods due to lack of displacement and a tiny turbo.

    Stock classes for SCCA only allow shocks (not springs), one sway bar and a catback. I'd be shocked to see ford offering the STs suspension / brake package , I don't see there being enough of a tuner market for the 1.0l.

    Don't get me wrong I think it will be a fun little car but I don't think it'll hold a candle to the ST.
    Smokin likes this.
  21. wash

    wash Active Member

    I think a few 1.0s will get hand me down KP39 turbos...

    In England people are already tuning the 1.0s.

    If you want to see the future as of two years ago, read about the Ricardo HyBoost Focus 1.0.

    Its not a question of if people will hotrod a tiny displacement turbo econobox, its when will a manufacturer make it so easy that people will line up to buy them for the performance value?

    Ford could do it in a few months and win some autocross championships in the process, all with a parts bin car since the hard work has already been done for the ST.

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