Swapping in 6.2L throttle body on 5.3L motor

M1ck3y · January 17, 2022

On 1/14/2022 at 9:44 AM, pokismoki said:

i think the ported lt5 tb on a stock motor is a waste of effort, thats only for S/C or built motors

stock 5.3 with 6.2 manifold and stock 6.2 tb is good enough, unless you plan on doing a set of l83 blended and ported heads, wont see any more gains

Yeah, it's almost as bad as doing what flying fool recommended. Swap in a l86/lt1 cam on the l83; he estimated there be about a 10hp gain!

95mm tb on the lt1 seems to be about a 15hp gain at peak. I think the l86 might have more to offer.

An unrestricted 87mm id tube has an area of 9.24 square in.

The lt5 tb has an area of 8.296 at the pinch point (shaft/blade) if it's modified to open fully (soler performance).

On the l86 manifold/lt5 tb the most area you can hope for is 7.069 if you port it, and put an angled spacer on. 7.67 in with the half shaft.

In fact there's no point in porting the throat except to give more space between the floor and the blade. The area of the throat is is still more then the unrestricted area of the 95mm. Even with the throat being less than 87mm!

Technically the maf is a restriction. But I believe flow recovers by the time it reaches the tb (don't quote me on that). In which case in a perfect world you would have no variations in area right through to the plenum. Or at the very least nothing less then the said area.

The combustion event/pressure wave dictates air velocity in a appropriatly sized intake tube. Anything less than that size your choking it, anything greater and your just slowing air down. Moving the power around from low end to high end, and vise versa.

Edited January 17, 2022 by M1ck3y

pokismoki · January 18, 2022

you dont think the intake valve and intake port is the main restriction?

M1ck3y · January 18, 2022

6 minutes ago, pokismoki said:

you dont think the intake valve and intake port is the main restriction?

Absolutely the intake valve and pushrod pinch point (un-ported) are the main restrictions. Well. Unless someone has an intake manifold with an area that's smaller, "before" the valve. That said, even restrictions such as a venturi can create more power. Everything is application specific, nothing is a one size fits all.

Gm sized the throttle body/throat for low/mid range torque; along with enhancing afm operation and emissions reduction. It also performs very well at high rpm. But it doesn't perform the best that it can, at high rpm.

The same could be said for for low rpm. Strap an appropriately sized smaller tb on; throttle response, and low speed acceleration will improve.

GSQUARED · March 18, 2022

I'm doing some budget mods on my 2014 sierra l83, this budget build you mentioned with the l86 manifold, and lt5s 95mm throttle body. Would that be safe to run on a can tune? I have a superchips flashpaq.

pokismoki · March 19, 2022

i found there is more free horsepower available in correcting alot of the factory emmisions stuff built into the driveline on these trucks... spend your money on HPtuners and buy the training books. and the truck will outperform any bolt-on truck you meet on the street with a can tune..

sheeet just activating PE in the fuel tables will make 15 hp for free! Disabling the TCC in the trans makes atleast 5-8 hp

Edited March 19, 2022 by pokismoki

M1ck3y · March 19, 2022

On 3/18/2022 at 1:46 AM, GSQUARED said:

I'm doing some budget mods on my 2014 sierra l83, this budget build you mentioned with the l86 manifold, and lt5s 95mm throttle body. Would that be safe to run on a can tune? I have a superchips flashpaq.

You would require custom tuning to use the lt5 tb.