Do the tb bump stop mod or not?
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Do the tb bump stop mod or not?
I remember I saw a write up for the tb bump stop mod. Is this a good mod or a waste of time? I might just do the mod anyways. I don't see how it could hurt anything.
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if you plan on getting your throttle body ported they usually do the "bump stop mod" when they do the porting... shaner and jantzer both do great work on tb porting... as stated above check the slack in your cable... mine had a shitload of slack in it... if your car has tcs you can adjust it but on a non tcs car there is no adjustment... you will have to put some sort of spacer beween the cable and gas pedal under the dash... or in my case, my car is a 98 and has the smaller cam on the tb... i swapped the cam out on my tb for a 99-02 cam which is bigger and it took out every bit of slack i had... i guess i just got lucky
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if you plan on getting your throttle body ported they usually do the "bump stop mod" when they do the porting... shaner and jantzer both do great work on tb porting... as stated above check the slack in your cable... mine had a shitload of slack in it... if your car has tcs you can adjust it but on a non tcs car there is no adjustment... you will have to put some sort of spacer beween the cable and gas pedal under the dash... or in my case, my car is a 98 and has the smaller cam on the tb... i swapped the cam out on my tb for a 99-02 cam which is bigger and it took out every bit of slack i had... i guess i just got lucky
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When looking at mine it wasn't opening near 90%. I used the voltage method and it got it to damn near right on 90%. It looks way better now. Some of the porters don't do this mod or the knife edge anymore. On TCS cars the cable won't pull it to the new stopping point after you mod it. You will have to pull the cover off the TCS unit on the passenger fender and cut the small rubber stopper out that keeps the cable from pulling the tb completely open.
Last edited by 01ssreda4; 12-05-2009 at 09:55 AM.
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I'd recommend going by voltage. I sent mine off to get ported and got it back with a bumpstop so badly ground off the throttle blade was pointing slightly upwards. Curious, I ran the voltage and it was rediculously over. Codes galore and one 16 second quarter mile had me putting some aluminum duct tape on there to fix the problem.
Do NOT go to far.
Do NOT go to far.
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only cars with tcs have that adjuster... that was stated in my first post... even if you do have that adjuster it won't always take all the slack out so you will have to add spacers or if you have the option as i did, swap out to the bigger 99+ cam
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you should be able to see where they ground down the bumpstop... it will be fatter on one part and thinner where the screw in the cam will hit it... some guys have a steady hand so it's smooth and hard to tell unless you look really close... you can also open the plate all the way and if it opens at a full 90 degree angle then you're good... if the mod isn't done the front of the throttle plate will be facing down just a little bit because the bumpstop isn't allowing it to open all the way
#14
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I always do the bump stop, but you can't really tell after I coat it since I remove the material first. I'm one of those steady hand guys, to so its not that obvious either way
I'm fairly conservative on my approach with that, the last thing I want is a customer telling me I went too far. I go just enough to get the blade open but that's it. I've ported a ton of LS1 throttle bodies at this point and no complaints so far lol.
I'm fairly conservative on my approach with that, the last thing I want is a customer telling me I went too far. I go just enough to get the blade open but that's it. I've ported a ton of LS1 throttle bodies at this point and no complaints so far lol.
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I port em for local guys, and I always do the bump stop mod. However, I do not do it according to voltage. I use my machinist square, which allows me to get it PERFECT.
As already mentioned, some cars will require some tweaking to get the throttle cable where it needs to be to get the benefit of the blade opening the full 90 degrees.
As already mentioned, some cars will require some tweaking to get the throttle cable where it needs to be to get the benefit of the blade opening the full 90 degrees.
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Does the truck DBW throttle body have the same 'bump stop'?
I've considering having mine ported, especially since I am ditching the truck intake soon in favor of a LS6 intake.
I hope since my LQ4 is already cammed the ported TB will add nicely to the power figures.
Thanks!!
I've considering having mine ported, especially since I am ditching the truck intake soon in favor of a LS6 intake.
I hope since my LQ4 is already cammed the ported TB will add nicely to the power figures.
Thanks!!
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I understand what you are trying to say. In your little world you got the blade to be at exactly 90 degrees so you did a perfect job. If the computer measured with a carpenters square every time you went WOT, then yes you would have done it perfect and you and the computer would agree on that. However, the TPS sensor is the computer's version of your carpenters square and that's what it will read every time you mash the gas.....So in the end it doesnt matter what the hell your carpenters square says, it only matters to the computer what voltage it reads from the TPS. The voltage way is the right way.