07NBSChevy

iTrader: (1)

Is there any benefit of porting my stock NNBS intake and running a 90mm throttle body for more power. I am running the stock 87mm throttle body and have a max rpm of 6200.

I talked to a reputable shop that does porting and they say I can gain 10-15 whp from porting the intake from 2000-6500 RPM. Now I do not know if this is true and wanted to ask before I have any work done.

99 Black Bird T/A

iTrader: (4)

On an

99 Black Bird T/A

iTrader: (4)

When my 99TA was a bolt on car porting the stock LS1 was worth 3 rwhp at the local dyno. Your stock TB is bigger than the old LS1 TB, so on stock engine Gen IV without other supporting mods I wouldn't expect much from porting the TB. It will help later with more mods.

NNBS intake is the TBSS intake?

The TBSS intake the best factory cathedral intake. I would expect proper clean up to gain a little bit on a stock engine and more on a modified one but I don't have any data from 1st hand experience with ported TBSS intakes.

07NBSChevy

iTrader: (1)

I wonder why my Sig isnt showing.
2007.5 NNBS ECSB LTZ 4X4 5.3/Built 4L70E with the stock 1600-1800 stall converter, 4.56 gears with 34" tires, 5,500 lb truck weight.
Gen4 LMG 5.3 with a BTR Truck Stage 2 cam (212/218 .553/.553 113+2), PRC Stage 1 ported 243 heads milled to 63cc, Cometic head gaskets 3.910" bore 0.045" thickness head gaskets, 10.5:1 static compression, 8.5:1 Dynamic Compression, 165 cranking PSI, 0.038" quench, ARH 1-3/4" x 3" longtubes, Corsa Sport 3" Catback, Airaid Jr kit. 6,000 rpm shift points, 6,200 max rpm. Blackbear 91 tune.

Yes NNBS is internally the same as the TBSS. I heard switching from the stock 87mm TB to a 90mm TB in a H/C 5.3 will gain 5 RWHP with a better throttle response. 3mm is not much bigger. Now, is it worth buying a new LS3 TB, probably not, but I have a new one laying around that I was going to use on another engine or go with a NW 102.

Now I have heard mixed reviews on portong the NNBS with price vs gains. My main goal is to maintain the low end without any loss but show gains up to 6,000 RPM (My shift points). I would like to get as much usable power up to 6k rpm possible out of the engine even if it is 5 more hp.

99 Black Bird T/A

iTrader: (4)

It sound like your heads & cam 5.3 would probably benefit from a ported TBSS & port matched 92 mm TB. It might be a small gain or it might be a surprising good gain.

I suggest contacting Peak Performance and discussing with them.

07NBSChevy

iTrader: (1)

That was the company who I was looking into for the porting.

As of right now I threw on the LS3/LS7 Throttle body, I will need a tune but did notice a slightly better throttle response in the lowend.

I will talk to them and see what are my best options.

brandon6.0

iTrader: (32)

anytime u gain airflow u will gain horsepower. Hinse the reason u add a cai or fast intake or bigger tb u gain power. I would take the stock tb and port it out. I did this to the ss and noticed a lil better throttle response. The tbss intakes is the best flowing truck intake, but with porting it should flow more. Ive seen threads on guys gaining 15rwhp with a ported tbss intake.

07NBSChevy

iTrader: (1)

Well I sold the stock 87mm throttle body today. So stuck with the LS7 90mm throttle body. I will look into porting that as well as the intake.

brandon6.0

iTrader: (32)

Even better!

99 Black Bird T/A

iTrader: (4)

07NBS,

FWIW - Peak Performance ported my 90mm TPiS snout LS6 intake manifold. The quality of work seems excellent. I'm happy with the performance of the intake on my small cam 383 LS1 stroker. It out preformed several big name intakes in dyno testing on my stroker. The engine is a fun daily driver type build not an all out weekend warrior.

When I'd planned to have my Dorman LS2 intake ported, I intended to use Peak but move to an LS3 style intake for that project.

Let us know what sort of results you get please.