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  1. #1
    Member
    Join Date
    May 2004
    Location
    Rochester, New York
    Posts
    45
    Corvette(s)
    1986 two-tone gold coupe

    Default throttle body upgrade question

    I have an '86 corvette, mostly stock. The throttle body in my car is shot and needs to be replaced. now I know that the stock size throttle body for my car is the twin 48mm set up. my question is, if I were to put a twin 52mm or 58mm aftermarket throttle body on would it throw an SES code?

    My car already has some sensitivity issues reguarding codes 32,33,and 34 and I've come to the conclusion that this could all be fixed by a new throttle body. I believe the slop in the shaft is allowing excess air through and making the computer think that either the MAF or TPS is bad.

    My final question is, Is there an aftermarket chip I can buy that will tell my car to either ignore the relation between the TPS and the MAF, or to just ignore the TPS all together?

    and of course, as always any other advice reguarding this problem is more than welcome.

  2. #2
    Member
    Join Date
    Oct 2006
    Location
    Hazel Park MI
    Posts
    19
    Corvette(s)
    85 4+3

    Default

    Your ECM will read the values of the TPS & MAF at WOT, so it's something you probably shouldn't mess with. You can get the stocker rebuilt & bored to 52mm which may be more cost effective than a new unit.

  3. #3
    Member
    Join Date
    May 2004
    Location
    Rochester, New York
    Posts
    45
    Corvette(s)
    1986 two-tone gold coupe

    Default

    the size isn't the problem, it's just easier to find 52mm throttle bodies than 48. and idw deal with a rebuild, I want a new one.

  4. #4
    Member c4cruiser's Avatar
    Join Date
    Feb 2002
    Location
    Lacey, WA USA
    Posts
    992
    Corvette(s)
    87 Gold Z52 Coupe 02 EB Z51 Supercharged Coupe

    Default

    Unless you have extra cubic inches( like up around 383 cid) , a big cam, head work and intake runner porting, the stock 48mm TB will provide all the airflow a stock moter needs. A 52mm will work, but going above that really won't do a lot for increased power.

    There are some good quality remanufactured TB's available and many will have sleeves in the TB to get the shaft tight and smooth again.

  5. #5
    Louis Bartay
    Guest

    Default

    Quote Originally Posted by CarDemon04 View Post
    I have an '86 corvette, mostly stock. The throttle body in my car is shot and needs to be replaced. now I know that the stock size throttle body for my car is the twin 48mm set up. my question is, if I were to put a twin 52mm or 58mm aftermarket throttle body on would it throw an SES code?

    My car already has some sensitivity issues reguarding codes 32,33,and 34 and I've come to the conclusion that this could all be fixed by a new throttle body. I believe the slop in the shaft is allowing excess air through and making the computer think that either the MAF or TPS is bad.

    My final question is, Is there an aftermarket chip I can buy that will tell my car to either ignore the relation between the TPS and the MAF, or to just ignore the TPS all together?

    and of course, as always any other advice reguarding this problem is more than welcome.
    Call this guy, he does a good work. He can just rebuild your TB and keep it the stock size or go larger.
    Louis

    From: David Koldos [mailto:dkoldos@ameritech.net]
    Sent: Wednesday, September 13, 2006 7:21 PM
    To: Louis Bartay; dkoldos@ameritech.net
    Subject: Re: 96 LT4


    Louis
    Thanks for the inquiry. Here's my standard spec sheet and prices:

    LT1/L98 Throttle Body Detail List

    $190 LT1 based 52mm throttle body, walnut shell blast cleaning, sealed roller bearing throttle shaft

    $215 1992-94 Corvette and 1985-1992 L98 based 52mm body, same as above but having the egr port area inserted and repositioned on the 85-92 bodies for proper operation with the larger throttle bore. 1992-94 Corvette bodies will only have the area inserted; there is no port to reposition.


    $145 Sealed roller bearing throttle shaft work by itself, all style bodies.

    $40 A set of new 48mm throttle blades for any of the the above. Better fit than stock, may help bad IAC counts and fuel trim problems

    $49 optional, provide, install and match bore a Hypertech style (not a real Hypertech) air foil


    $28 optional, OE GM throttle body gasket kit. Includes the top cover, plenum to throttle body, iac plate and for the LT1’s, the TPS foam seal and IAC O-ring.


    $18 shipping and prepaid return label for your old throttle body if you purchase a finished body I have here


    $9 shipping if a customer sends their own throttle body for the modifications, three-day turnaround plus shipping time


    $00 match bore an airfoil a customer provides

    $50 core deposit if purchasing a body I have here, refunded when I receive a rebuildable core of the same style I sent. Does not apply to corvette or impalass forum members


    Payment methods: money orders or credit cards thru paypal.com in which case I send a fund request email thru their site.

    Address:

    David Koldos
    810 Olive St.
    Elgin IL 60120
    847-840-3415 cell
    dkoldos@ameritech.net


    Let me know if you need additional information.
    Thanks
    David

  6. #6
    Technical Writer for Internet & Print Media
    Join Date
    Jan 2001
    Location
    Southern California
    Posts
    6,461
    Corvette(s)
    71 95 04 12

    Default

    A mostly stock L98 hardly needs 52mm throttle bores much less 58mm bores.

    In fact, you put a large bore TB on an engine like that and you're probably going to have a net zero performance gain, a loss in driveability and perhaps even a performance loss.

    I'd replace your worn TB with a new one with stock bores.
    Hib Halverson

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