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Thread: Converting a SM to a full ITA ride "build"

  1. #1
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    Default Converting a SM to a full ITA ride "build"

    So the last few times I've been on track, I've ran the SM in ITA. I'm really happy being back in IT, and want to convert the car over to full ITA spec car (as budget and time allow). I know the 1.6 isn't ideal, but it is what I have.

    The car is a tiring crate 1.6, with a nice header on it. Other than that, it is full SM. I've finally got all the electrical bugs worked out, so that's not an issue, but I do need to go back and strip out the ABS wiring from the harness.

    It has one issue, that I need to figure out a fix for... under heavy straight line braking, it feels as if it "hops" in the front. I'm thinking the bilsteins are worn and causing the hop. If that's the case, can I use the SM coilovers with Koni's, or do I need a new setup? If so, what's a good spring rate to start with?

    As for the motor, does removing the emissions vacuum goodies do much, or should I even bother?

    Is there a good enough gain with a Megasquirt PNP? If so, from what I've read, it's possible to eliminate the AFM from intake. Is that something allowable, doable, worth it? If not, what cold air intake do I need to look for?

    Thanks!

    hoop
    hoop
    Greensboro, NC
    STL Newbie

  2. #2
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    Is there a good enough gain with a Megasquirt PNP?
    Yes.

    As with most cars, you're going to hear a lot of different opinions. It also depends on your driving style. I'm sure Andy will chime in as he had one of the best built ITA Miatas out there.
    Dave Gran
    Real Roads, Real Car Guys Real World Road Tests
    Go Ahead - Take the Wheel's Free Guide to Racing

  3. #3

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    Quote Originally Posted by iambhooper View Post
    It has one issue, that I need to figure out a fix for... under heavy straight line braking, it feels as if it "hops" in the front. I'm thinking the bilsteins are worn and causing the hop. If that's the case, can I use the SM coilovers with Koni's, or do I need a new setup? If so, what's a good spring rate to start with?

    Is there a good enough gain with a Megasquirt PNP? If so, from what I've read, it's possible to eliminate the AFM from intake. Is that something allowable, doable, worth it? If not, what cold air intake do I need to look for?

    Thanks!

    hoop
    I had Ohlins shocks in my old car, and I'm going to move back to them this winter. There's lots of options for spring rate.

    The Megasquirt is a good aftermarket ECU, and you will pick up power (and have the ability to adjust the redline, which helps, too).

    Keep in mind the rules regarding the AFM state:

    "On cars so equipped, the air metering/measuring device (i.e. air flow meter, air mass meter, MAF) must be operational and shall not be modified."

    -jeff
    Last edited by jwasilko; 11-10-2013 at 03:25 PM.
    #08 ITA/STL Miata

  4. #4
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    Quote Originally Posted by jwasilko View Post
    I had Ohlins shocks in my old car, and I'm going to move back to them this winter. There's lots of options for spring rate.
    While I have no doubt they are nice, $3000 "may" be out of my budget for this car (or any). Hence, why I was aking about using the SM coilovers on Koni's.

    The Megasquirt is a good aftermarket ECU, and you will pick up power (and have the ability to adjust the redline, which helps, too).

    Keep in mind the rules regarding the AFM state:

    "On cars so equipped, the air metering/measuring device (i.e. air flow meter, air mass meter, MAF) must be operational and shall not be modified."

    -jeff
    I thought that was the case, but a fella can whish.
    hoop
    Greensboro, NC
    STL Newbie

  5. #5

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    Might be worth looking at ISC's suggestions:

    http://iscracing.net/miatasuspension.html
    #08 ITA/STL Miata

  6. #6
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    Quote Originally Posted by jwasilko View Post
    "On cars so equipped, the air metering/measuring device (i.e. air flow meter, air mass meter, MAF) must be operational and shall not be modified."
    Note that the intent of that rule is not that you have to use its signal, it's to keep you from modifying its mechanical "operation" -- and thus air restriction. Other regs allow you to install a MAP (if not already equipped) to properly work with the Megasquirt.

    We've debated this back and forth, but no one has yet to come up with a good verbiage to replace that, without allowing some level of intorturation of the MAF.

    - GA
    Not my circus...not my monkeys...

  7. #7
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    Quote Originally Posted by Greg Amy View Post
    We've debated this back and forth, but no one has yet to come up with a good verbiage to replace that, without allowing some level of intorturationof the MAF.

    - GA
    Googleing that word didn't provide me with a definition, instead it provided me with http://tgadrivel.blogspot.com/2012_11_01_archive.html

    For which I will need to find some time to read.

    Nonetheless, I believe I understand the idea behind the "word". Either way, if/when I do a Megasquirt, it would be a good idea to let someone who know's what they are doing do with it what they will.
    hoop
    Greensboro, NC
    STL Newbie

  8. #8
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    A good portion of the guys run their ITA Miatas with the SM set up. That's probably the best/cheapest way to go. The biggest bang for your buck is getting more horse power. Magesquirt is a good start just make sure you know someone local who can tune it.
    Jeff L

    ITA Miata



    2010 NARRC Champion

    2007 NERRC Championship, 2nd place
    2008 NARRC Championship, 2nd place
    2009 NARRC Championship, 2nd place

  9. #9
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    Check with Ron M, he had his MS conversion done by Peter Florence as did Jeff Young.

  10. #10
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    Sell the 1.6 SM, buy a 1.8 SM for similar money and THEN do a conversion to ITA.

    Then call me.
    Andy Bettencourt
    New England Region 188967

  11. #11
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    Quote Originally Posted by Andy Bettencourt View Post
    Sell the 1.6 SM, buy a 1.8 SM for similar money and THEN do a conversion to ITA.

    Then call me.
    If I sold the car, and was dumb enough to buy another, it would be a FWD somethinorother. Hence, I'm trying to patch up what I got. We've been competitive in ITA, but I'm always looking to improve things.
    hoop
    Greensboro, NC
    STL Newbie

  12. #12
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    I know Andy is biased and probably justifiably so. On the other hand, folks think a full prepped 1.6 ITA Miata at LRP would do very well, if not, get close to the lap record set by Andy's 1.8 ITA Miata before weight was added. Bruce Perry's 1.6 ITA Miata is living proof that that car can kick ass at WGI as well (2.17's if remember correctly).
    Demetrius Mossaidis aka 'Mickey' #12 ITA NESCCA
    '92 Honda Civic Si
    STFU and "Then write a letter. www.crbscca.com"
    2013 ITA NARRC Champion and I have not raced since.

  13. #13
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    I ran the same time as my track 2007 record at the 2012 NARRC Runoffs with teh extra poundage...the only thing holding the car back is a fresh driver. Getting on the track once a year just isn't good enough from a driver skill standpoint. It's a mid 1:00 car there. It's been 1:00.8 with less power.

    I do think the 1.6 could be a fine LRP car but that is an anomaly of a track. Trust me when I say that a full-tilt 1.8 ITA car at WGI is a low 2:16 car all day long. All you need to have is a 'Leverone' who will drive anything anywhere to validate.

    The biggest advantage is the torque output and curve of the 1.8. Something I highly value.

    If you want wrong-wheel drive, go for it! Just make it an ITR car!
    Andy Bettencourt
    New England Region 188967

  14. #14
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    Quote Originally Posted by Andy Bettencourt View Post
    I ran the same time as my track 2007 record at the 2012 NARRC Runoffs with teh extra poundage...the only thing holding the car back is a fresh driver. Getting on the track once a year just isn't good enough from a driver skill standpoint. It's a mid 1:00 car there. It's been 1:00.8 with less power.

    I do think the 1.6 could be a fine LRP car but that is an anomaly of a track. Trust me when I say that a full-tilt 1.8 ITA car at WGI is a low 2:16 car all day long. All you need to have is a 'Leverone' who will drive anything anywhere to validate.

    The biggest advantage is the torque output and curve of the 1.8. Something I highly value.

    If you want wrong-wheel drive, go for it! Just make it an ITR car!
    Even though I've never driven it, I know well enough to know that VIR and LRP are 2 entirely different tracks.

    Am I wrong in thinking that the only difference between a 1.6 and a 1.8 is the motor and dash? If so, couldn't I just do like I did with the carbed ITC CRX and convert it over? The GCR allows for this.
    hoop
    Greensboro, NC
    STL Newbie

  15. #15
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    There's a thread somewhere here on making a 1.8 ITA out of a 1.6 in ITA. It's more work than you think. Just ask Jim Alley.
    Demetrius Mossaidis aka 'Mickey' #12 ITA NESCCA
    '92 Honda Civic Si
    STFU and "Then write a letter. www.crbscca.com"
    2013 ITA NARRC Champion and I have not raced since.

  16. #16
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    Quote Originally Posted by mossaidis View Post
    There's a thread somewhere here on making a 1.8 ITA out of a 1.6 in ITA. It's more work than you think. Just ask Jim Alley.
    +1
    Andy Bettencourt
    New England Region 188967

  17. #17
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    hoop - make sure you still have the 1.6L rear end in that car, 1.8L parts are legal in SM And NOT in ITA.

    the 1.6L doesn't have a throttle position sensor "really". it has a button that tells the ECU "yup, It's open". mazda did the same on the S4 engine RX7s - maybe even later. ITCS allows you to add or replace a TPS. do so - it will pay big dividends with the ECU, and an MSPNP can be made to work with just about any TPS.

    I think the 1.6L properly done should be a reasonable A car. have fun.

  18. #18
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    Quote Originally Posted by Chip42 View Post

    the 1.6L doesn't have a throttle position sensor "really". it has a button that tells the ECU "yup, It's open". mazda did the same on the S4 engine RX7s - maybe even later. ITCS allows you to add or replace a TPS. do so - it will pay big dividends with the ECU, and an MSPNP can be made to work with just about any TPS.
    Both of those cars came with the flapper-style AFM. Later cars had the MAF.
    Andy Bettencourt
    New England Region 188967

  19. #19

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    Quote Originally Posted by mossaidis View Post
    There's a thread somewhere here on making a 1.8 ITA out of a 1.6 in ITA. It's more work than you think. Just ask Jim Alley.
    I'm glad to have picked up that car :-)
    #08 ITA/STL Miata

  20. #20
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    Interested to hear/see what you're doing here Hoop. I just picked up a 1.6 after renting a friends this past season and I'll be converting to ITA sometime after 2014. I'll be running in ITA in SM trim through May, then I gotta be busy as a baby daddy so that'll give me the rest of 2014 to be better prepped for ITA.

    See ya on the track!
    Morgan Mehler
    NC Region
    ITA/SM '91 Miata
    ITB '84 GTI - The Brick - FOR SALE

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