Topic: LS1 throttle body on the 5.3?

[02Z71_Tonka]

Like the title states, will a throttle body from the LS1 bolt on to the 5.3? Found a 85mm ported LS1 throttle body, but want to make sure if it will work or not.

Thanks

[Main One]

The main thing to keep in mind relative to putting an LS1 compatible TB on your application is whether you are currently running a cable operated one or a stepper motor (drive by wire) one, and whether the LS1 TB you are thinking about is the same or different.  You can do a conversion from one to the other, but I myself would try to stick with the type the truck and computer is already set up to deal with.

02 Avalanches were the only year that had the cable TBs.  03s and later are drive by wire stepper motor driven.  From what I've seen, there's more options out there, and usually a bit cheaper, for the cable TBs.

[02Z71_Tonka]

So as long as the LS1 throttle body is cable I can use it on the Avy then?

[Main One]

I've thought about a TB upgrade from time to time, but never pulled the trigger myself.

I'm pretty confident that the LS1 cable TB will bolt onto your block, but am not sure about it being compatible with the stock truck intake manifold.  I think it is, but I'd do a little more homework myself before spending the $.

Bob mentioned that by looking at a log, he knew where his converter stalled.  He and I both use HPTuners to do our own computer tuning, and it has a logging function where we can look at a wide range a data going in and coming out of the computer, such as rpms for seeing where a converter stalls.

I've looked at my manifold air pressure (MAP) sensor reading on just about every one of my hundreds of logs.  I'm running a custom ram air intake through my aftermarket hood's air scoop, and a K&N filter mounted less than a foot away from my stock throttle body.  At WOT, as the airflow goes up with rpm (with my cam, I make peak horse power around 5500 rpm and it doesn't really fall off, at least not at rpms that I'm running) I can see my MAP readings drop a few percent.  Where the restriction is, I don't know.  My filter is not all that large, but I'm sure there is some restriction to it.  I've got a 90 degree bend between the filter and TB which may offer some restriction.  But the bottom line is even if all of the restriction is in the TB, and I could get rid of all of it, absolutely best case, I don't think a larger TB would gain me 10 HP at the rear wheels.  As noted before, I'm already fuel injector limited anyway - more air via the larger TB would make that limiting factor a concern.  I am thinking about getting larger injectors, large enough to handle a good dose of forced induction, but that will be after I rebuild the tranny to handle it.

[bluedevil]

M1, when you say "drive by wire stepper motor driven", you mean electronic?   I have a BBK 80mm TB waiting to be installed.  My first attempt ended up breaking the cast from the original TB while removing the electronic motor.

[bluedevil]

You 02's are lucky,.... you dont have to perform a surgery like us electronic TB owners.

This pic is Flabouy's, the motor and electronics need to be swapped to the new 80mm.

[Main One]

Yes, stepper motor is driven by the computer, so it is "electronic".

Do you think FB is going to like you posting a pic of his?

Now that MBT is a global moderator, maybe we should re-engage FB?

[bluedevil]

Do you think FB is going to like you posting a pic of his?

The pic is off our gallery..

[KY_BOB]

I have a 80mm BBK on mine.  It was a 15 minute swap and easy to do.  I honestly don't think I gained anything from it because there is a resin adapter plate that necks from the TP opening down to the manifold opening and it's still the same size. 

I guess due to the restriction of the throttle blade and shaft there could be a little room for improvement even though the air still has a slightly smaller restriction behind it.  It probably makes more difference now than it did at the time that I put it on.  I was NA then.  I flow a lot more air now than I did then, (at 6200 rpm I can max out my MAF @ 12,000 hrz) so I would say that the potential is greater for improvement.

[Main One]

I have a 80mm BBK on mine.  It was a 15 minute swap and easy to do.  I honestly don't think I gained anything from it because there is a resin adapter plate that necks from the TP opening down to the manifold opening and it's still the same size. 

I guess due to the restriction of the throttle blade and shaft there could be a little room for improvement even though the air still has a slightly smaller restriction behind it.  It probably makes more difference now than it did at the time that I put it on.  I was NA then.  I flow a lot more air now than I did then, (at 6200 rpm I can max out my MAF @ 12,000 hrz) so I would say that the potential is greater for improvement.

Bob, we're going to make an engineer out of you yet!  It's bad when the engineers have to interpret for the insurance guy, LOL!

The Mass AirFlow (MAF) sensor has an output with an AC-like signal.  The frequency of the signal is correlated to the flow of air through the MAF.  The max frequency is around 12 KHz, and there is a max airflow value that can be entered into the correlation table that correlates in the neighborhood of 500 hp.