Quarter Mos & Ultimate TBI mod
 

Hello Folks,

I've been reading about these two mods here in the forum, but can't find what they really are about?
Can anybody point me to the actual mods?

Thank you.
WorstCases

The quarter mod is simply adding a quarter under the spring on the throttle body injection (TBI) fuel pressure regulator.

I'm not exactly sure what is considered the 'Ultimate TBI Mod' as there are a few that make decent gains, but if you have references to the threads where you read about them post links to the threads and we can try to clarify for you. You could also Google those two things and I'm sure you'll get some results.


All of that information is useless to you unless you have an older TBI equipped Blazer... :icon_wink:

I read it here:
https://blazerforum.com/forum/engine...tonight-61805/

Didn't find anything on Google about the quarter mod.
I was wondering if the "ultimate TBI mod" was the one where you grind off the wings/flabs on the throttle valve (is it called the butterfly?).

If there are more than these mods to the TBI, please let me know.

Is there some more information about the quarter mod? What does it do? More fuel pressure, more fuel in the chamber? If so this should be overwritten by the computer as the o2 reads too rich...?

That thread is for people with a TBI engine. So unless you have a TBI engine, those mods are not for you. What is it that you are driving? Year, model, engine, etc.? Might want to put that information in your profile somewhere or create a garage for your truck so the information prints out under your screen name!

I did try to find the Garage settings... Didn't find them yet.

I'm driving 2000 Blazer 4x4.
Will update Garage, as soon as I find out where.

Thank you!

Its in "user cp" to left of your screen. Or where it says garage to right.

Yea,that tbi stuff does not apply to your blazer,since its a 2000 model. The quarter bumps up the fuel a tiny bit,as the tbi engines run a little lean. Helps with throttle response.

Okay...don't want to sound dumb, but I cannot find where to put the quarter. That's what you guys mean right? Or turn a bolt/screw a quarter turn?

Unless you have a way to check the fuel pressure before and after I don't suggest the quarter mod. You could already be at the ideal 13psi for a TBI and easily raise it too much. Besides its not hard to make the factory reg adjustable. Still need a fuel pressure gauge.


On a TBI it draws air from the side and not top down. The ultimate mod is to grind down, blend, smooth the ridges around the venturi. You also stack 2 injector pod gaskets to raise the pod for more flow. Some people go as far as to grind down the butterfly shafts so they are thinner and air can flow into the tbi easier.

But like said on a 2000 you don't have TBI so its no help.