Here are dyno results from Peak Speed Shop's Radical porting of a Gen III GM Truck Intake Manifold.

Stock 2001 GMC Sierra 1500, 5.3L. A tune was done prior to the "before" results to factor out the effects of just tuning the stock setup. Dyno was before/after test on ported intake and throttle body only.

7 Gain in Peak RWHP
6.5 Gain in Peak RWTQ

Gains were seen throughout the power curve with points in the curve seeing as high as:

9.5 Gain in RWHP
9.5 Gain in RWTQ

Intake manifold inside before RADICAL porting. Obstructions cause poor airflow to 4 cylinders.



Intake manifold inside after RADICAL porting. Obstructions cause poor airflow to 4 cylinders.





To order, go to TRUCK - Intake Manifold : Peak Speed Shop, Boosting Horsepower...Adding Style! or call us at 719-651-1952.

 

Very impressive for those weak motors...especially considering it's at the rear wheel!

 

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I wonder what the diff is on turbo trucks.

 

I would expect better results since you can benefit even more from better airflow from the turbos.

 

How does the flow of a ported gen III Intake compare to a stock nnbs intake?

 

We don't have flow numbers for comparison. However, I can tell you that the cathedral port nnbs TBSS intake manifold would flow considerably better. First, it has a 90mm throttle body opening rather than a 78mm throttle body opening. The plenum space is significantly larger, too.

Here is a photo of the GenIII intake and the GenIV intake:

GenIII


GenIV


However, you will probably discover that the cost of switching over to the GenIV TBSS intake manifold, fuel rails, etc. would cost nearly as much as simply going to the FAST LSXRT manifold.

 

I wouldn't bother with intake improvements with a turbo. The turbo does the work, not the intake in that case...so the gains are minimal. My edelbrock pro flow is only on my truck for looks lol. Stock48 runs 9s in his truck with a bone stock gen 3 intake lol. Turbos make airflow issues in the engine go away

 

I was thinking about going with the edelbrock but talking with stock48 said youll lose some lowe end tq. I to dislike the stock intake look.

 

Yeah he gives me **** about that as often as he can lol. You'd be hard pressed to notice the difference though. My truck has a ton of low end though.. It will spin all 4 tires past 60mph. I don't think it's missing much without the truck intake.