• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

5.3L performance TB upgrade?

Mack201

Full Member
Joined
May 19, 2008
Messages
39
Has anyone here checked into using a TB from a vortec 6.0L in your vortec 5.3L ?

I have changed the TB on my 2.5L jeep to the TB from a 4.0L jeep with good results as the 4.0L TB was 10mm larger and the same bolt pattern.  All I had to do was change over my original AIS motor to get the correct idle and open up the manifold to match the opening of the larger TB

My 2003 vortec 5.3L TB is 72mm and I see aftermarket TB at 80mm but I cannot find any information on a stock 6.0L TB

I do not want to spend $300-$500 on an aftermarket TB if I can have similar results with a junk yard vortec 6.0L TB for $50.

If the 6.0L TB is has the same venturi opening, would grinding the lip from the back of my stock 5.3L TB make any difference?

 
I have an aftermarket 80mm TB but I haven't heard of a cheap way to upgrade other than having the factory one ported.

You might check on performancetrucks.net for some tips.

 
I read somewhere today that the factory 6.0L TB may have been 78mm.
Can anyone confirm this to be true?

 
I dunno if this helps but I found it just now:

A summary of new or changed components for the Gen IV architecture:

Larger 90-mm throttle body: The 6.0-liter displacement requires a higher volume of intake air; the Gen III throttle body is 75 mm. The new throttle body is mounted to a revised-design composite intake manifold with tuned runners to optimize airflow to individual cylinders.

http://www.gminsidenews.com/forums/74300-post17.html
 
That is all well and good except for the fact that I took off my TB from my 2003 5.3L and it measures 72mm.

Larger engines need more CFM therefore larger TB.

If the 4.8/5.3/6.0 used the same 78mm TB, does the computer restrict the maximum opening as the 4.8L will certainly not require the same CFM as the 6.0 assuming they use the same venturi TB?

This still does not explain why my 5.3L measures 72mm if you say they are all 78mm
 
Mack201 said:
That is all well and good except for the fact that I took off my TB from my 2003 5.3L and it measures 72mm.

Larger engines need more CFM therefore larger TB.

If the 4.8/5.3/6.0 used the same 78mm TB, does the computer restrict the maximum opening as the 4.8L will certainly not require the same CFM as the 6.0 assuming they use the same venturi TB?

This still does not explain why my 5.3L measures 72mm if you say they are all 78mm

OK mack  :rolleyes:  Go for the upgraded 6.0L TB then  (y)

I'll make it easy for you the GM part # 12570800
you may find that the part number on your current TB matches it.  :D
 
Thanks, I have noted the part # appears to be the same for the 4.8/5.3/6.0 so it appears that they are all the same bore.

I quess the next obvious question is will I see any difference in performance if I go to a modified TB such as 80mm and change nothing else?

The reason I ask is because it is drive by wire.
If the stock TB that is used is large enough for the 6.0L motor, it is certainly more than enough for the stock 5.3L
I assume because it is drive by wire, the TB will only open up to what the engine can match for the proper Air/Fuel mixture.
That being said, it would seem pointless to use a larger TB unless I also purchased a tuner to take full advantage of the extra CFM available.
If a larger TB is used and a tuner is used to modify the settings, will the injectors be sufficient or do they need to be upgraded also?

Is my thinking correct on this?

LIFE WAS SO MUCH EASIER WITH MECHANICAL TB'S
 
OK after all the replies, I went and purchased a ported TB and now I have an issue.

The computer is going into the reduced engine power with the ported TB.

If I pull the intake tube after the MAF off slightly so that not all the air runs thru the MAF, the idle comes down.

I let it run this way for a few minutes and slowly attempted to put the intake tube back on completely over the next several minutes but as soon as it seals and all the air is going thru the MAF the idle goes to 2K and stays there.

If I put my original TB on, the issue goes away.

Are there any tuners in the central massachusetts area on this forum that will take pity on my issue and help me out?
 
Mack201 said:
OK after all the replies, I went and purchased a ported TB and now I have an issue.

The computer is going into the reduced engine power with the ported TB.

If I pull the intake tube after the MAF off slightly so that not all the air runs thru the MAF, the idle comes down.

I let it run this way for a few minutes and slowly attempted to put the intake tube back on completely over the next several minutes but as soon as it seals and all the air is going thru the MAF the idle goes to 2K and stays there.

If I put my original TB on, the issue goes away.

Are there any tuners in the central massachusetts area on this forum that will take pity on my issue and help me out?

Who ported the TB ?  Seems like you should talk with them.
 
I did talk with them.

They primarily do wrive by cable and this was one of their first DBW.

After researching, they suggested I modify the MAF table.

I do not want to have to do that as if it goes to the shop and a stock tune is put in place, the truck will not operate properly.

TB is going back to them.

I still am looking for a ported TB that will not throw an engine code.
 
Mack201 said:
I did talk with them.

They primarily do wrive by cable and this was one of their first DBW.

After researching, they suggested I modify the MAF table.

I do not want to have to do that as if it goes to the shop and a stock tune is put in place, the truck will not operate properly.

TB is going back to them.

I still am looking for a ported TB that will not throw an engine code.

You say your in MA. contact Slowhawk over on www.LS1tech.com  He can port your TB and tune your truck for you.
 
Back
Top