Detuning a Boss 302 motor for on-track longevity?

Discussion in 'Boss 302 and S197 Technical Forum' started by The_Backmarker, Jan 27, 2019.

  1. The_Backmarker

    The_Backmarker TMO Intermediate

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    Since Boss 302 crate motors don't seem to exist anymore and the Boss 302 Road Runner motors seem to have a reputation for popping when driven hard, I'm thinking of detuning the motor in my Boss 302S to increase the odds that this motor survives for at least 5 years. It's a race car and will be raced in regional vintage races just for fun and run at the occasional time trial and track day. I won't be doing any serious racing with this car. I just want to have fun with it and keep the cost of ownership reasonable.

    By detuning, I mean running the motor a bit richer and also lower the redline from 7500 to 7000 rpm. Basically, sacrificing performance for durability.

    What are your thoughts on this and is there anything else I can do to increase the life span of the engine (and the rest of the car) while still putting it on a race track?
     
  2. VoodooBoss

    VoodooBoss Rick Moderator

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    Seems reasonable to lower the redline but not sure about running it richer but I'm sure it couldn't hurt. Are you using pump or race gas?
     
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  3. TMSBOSS

    TMSBOSS TMO Addict

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    Causes of failure in the Boss motor has been related to the oil pump and valve train. Although there are other failures, these are the failures I have read about most.
    I assume the S comes with the billet oil pump. Swapping out springs every season may also help.
     
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  4. BigTaco

    BigTaco TMO Addict

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    Don’t mess with the tuning but run high quality 100+ octane gas. Sunoco offers unleaded high octane that has a good storage life. If your not doing any serious racing, just enjoy it. It will be fine. There are far more examples of Boss motors being driven extremely hard at the track and living long lives than the few that have “popped”. Change the oil religiously with a high quality 5W50 PAO based oil.
    Take care, BT
     
  5. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    I wouldn't do any of that.

    Cool the oil

    Cool the oil

    Cool the oil.

    In that order. ;)

    And if you don't believe me, Cool the oil. :D We have a sticky thread on oil coolers. With the S, I'd just put a bigger Setrab one in place of the stock 915 Setrab. Not that much money for say a 934 and you're already plumbed for it.

    I would NOT run rich to 'detune'. That would just build up carbon faster and wash down the cylinder and reduce lubrication. Both are bad for engine longevity, IMO. Back off timing and lower the rev limiter or just shift early most times.

    Rev-match, heel-toe and don't 'drive it like you stole it' or power shift like a drag racer. Bad habits kill parts. Sounds like you already get that, but the smoother you are, the less shock on every single engine part.

    ^That too. :D
     
  6. The_Backmarker

    The_Backmarker TMO Intermediate

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    Thanks for the advice, guys. I'll be running Sunoco 260 GP (100 octane). I'll definitely check out that stickied thread. I have no problem short-shifting, too.

    Grant, it looks like we're both in SoCal. I live 5 miles away from Willow Springs (for better or worse, haha). Which track day outfits do you run with? I mostly run with SCCA (Cal Club), NASA, Speedventures, and ExtremeSpeed.
     
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  7. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    I'm down in Orange County...and I'd be in trouble If I lived up in Rosamond! Doesn't WSIR pump VP in the paddock? I usually get it from a 76 down in Newport. I normally run with SpeedVentures and the Cobra Club. Sometimes with ExtremeSpeed and Hooked on Driving. Mostly depends on the calendar/dates. Check out 50Deep's next event there too. Pretty sure I can't make that, but he puts on a great and safe event.
     
  8. DocB

    DocB TMO Advanced

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    You can safely de-tune a Boss 302S to run on 93 octane. It would perfectly address what you are asking for and be alot easier on the pocketbook.
    The decrease in HP would be negligible, and $3/gal. is alot better than 10$/gal.
    We have done this and it has worked out quite well. It's all in the tune-up.
     
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  9. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    We don't have 93 out here.
     
  10. BigTaco

    BigTaco TMO Addict

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    Yeah, don’t mess with “detuning” it. Factory calibration and high quality race fuel.
     
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  11. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    One more danger we have in Cali is 'winter blend' gasoline. So it's even crappier than normal 91, because they justify that you don't need as good gas when it's cooler in the winter. Refiners can ADD butane for a higher VOC blend. The other day it was 80º+ F out. :rolleyes::rolleyes::rolleyes::rolleyes::rolleyes:
     
  12. VoodooBoss

    VoodooBoss Rick Moderator

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    I ran race gas in my stock Boss for track days. Cheap insurance.
     
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  13. 2012-Boss

    2012-Boss TMO Addict

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    Unless I am mistaken, is the RPM limiter set at 8,200 for a 302S? 7,500 RPM is fine, you do not really need to short shift the engine.

    With regard to tuning the car, the first question is do you have access to a reputable Mustang / Coyote tuner that has first hand experience tuning road race cars? If not, you really should just stick with the factory tune and run race gas.

    If you do have access to a good tuner, then my suggestion is to simply have him or her log the car and examine the existing tune(s). Specifically look at fueling, ignition / spark timing, and cam timing. Depending on what the fuel and spark look like, you might be able to create a more conservative tune that is more appropriate for 93 octane gas.

    The Boss 302 street engine tunes, especially the TracKey, are on the lean side with more timing that what is really needed. You can have a more conservative tune with more fuel and less timing and not loose power. But, this approach will eventually damage the catalytic converters. Ford's tune has to meet a much broader set of requirements than a track only setup and is therefore constrained in optimizing the calibration for a very specific and narrow operating environment.

    With the 302S, the fuel and timing might be a little more aggressive because the expectation is you are running race gas. This is reasonable considering the cars intended purpose. Keep in mind that even a slightly richer fuel curve means more stops in a race, so running race gas is the smart thing to do from a competitive standpoint. For a track day car, fuel mileage is not as important.

    The last thing I would point out is how long do you expect or want the engine to last between rebuilds? You will easily spend $10,000 on a rebuild with no major engine damage. If running race gas saves you $5.00 per gallon, then you would need to run over 12,000 track miles to reach the break even point for a $10k rebuild ($10k / $5.00 = 2,000 gallons x 6 MPG = 12,000 miles)

    I agree with Grant that you should also look at lowering engine oil and coolant temps as a reliability measure. If you have a 2012, then you should look at a larger oil cooler. The later 302S cars came with a Setrab 948, which is one of the biggest coolers Setrab sells and does not need to be upgraded. Also, if this is a 2012, you might consider a billet grille and having custom ducting created to seal in the radiator. Again, this is not needed on the later cars because this was addressed from the factory.
     
  14. blacksheep-1

    blacksheep-1 TMO Addict

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    uhhh..no
    the engines used in IMSA were .020 over, new rod bolts and and valve springs, along with better oil pump gears and let them eat for 50 hours or more, one had ..about 75 hours on it. In all the years of IMSA, SCCA and PWC we had a cam phaser go bad one one..that was it that I recall.
     
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  15. Bill Pemberton

    Bill Pemberton TMO Addict

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    Not sure if changed , but my Boss 302S limiter is capped at 7800. This makes sense, as it pulls ( on the Dyno ) right to 7700, before it begins to fall off.
     
  16. steeda5

    steeda5 TMO Advanced

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    Boss intake signs off at 7700 rpm. Why not just short shift here and there? Race fuel is a must. Enjoy that car.
     
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  17. ChrisM

    ChrisM No bad days.

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    OT, but my first track day was at Willow Springs. I was stationed at Edwards. I actually would love to go to that track again, but California is at the bottom of places I'd ever want to live again. That there are not one, but TWO tracks right off base that I could go to and watch cars every weekend is probably the biggest reason I ever got into this, so I am still jealous you are so close.
     
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  18. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    What?! You don't want to come back to CA and pay taxes upon taxes that voters voted IN?!
     
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  19. TMSBOSS

    TMSBOSS TMO Addict

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    Please dont screw up a great site with talk about taxes and politics.
    Please
     
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  20. Grant 302

    Grant 302 OPM Spent: $587,402 Moderator

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    Just leave the politics out. Sales tax increase like was voted in here is a non partisan issue.
     

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