Is cleaning the upper and lower intake manifolds worth it? I cleaned my lower one with a wire brush to the best of my ability but i was wondering if cleaning the upper one was worth it?

 

you cleaned the low before the upper? what did you clean the out side? or are you talking about the inside?

 

I'm talking about the inside. I cleaned the lower first because i was short on time and it was a last minute thought.

 

What were you cleaning off it? Old fuel residue?
Yeah. Keeping the port clean is a good idea. You should have port matched them while you had them off. Better than just cleaning them.

 

question: i've been hearing about port-matching and how it produces power, but i can't find any how-to's or anything explaining explaining exactly what it is or how it's done on a VQ35.. can anybody help me out by pointing me to a good thread, or explaining it?

 

Don't know if there are any threads, but essentially it's a simple process.

1. Disassemble the upper IM from the lower IM.
2. Make a template (tracing paper, posterboard, gasket, etc.) of the ports at the mating surface between the upper and lower. You can use thin tracing paper first with an exacto knife, then transfer the image to poster board if you like.
3. Use the templates to mark the ports on both upper and lower.
4. Remove excess material around the ports with a die grinder
5. Slap it back together and floor it!

 

oh.. essentially, so the LIM and UIM stock inner channels at the mating surfaces don't match up perfectly, and that disrupts airflow?

and grinding down the LIM and UIM channels to match each other perfectly would create more horsepower by making airflow smoother?

 

Correct!!

The taping the studs method works great for this process!!

Portmatching the two surfaces is a must, specially if going to SSIM.

 

cool... this is a must-do then.. are there any dynos around to show how much horsepower is gained by port-matching?

 

Make sure you remove the lower from the engine prior to gringing. You wouldn't want metal in your cylinders now would you?

 

absolutely not.. lol.. that might suck a little bit... curious about the power gains though, if anybody has any info on that

 

Your gains would be directly propotionate to the degree in which your ports are mismatched. The degree of mismatch varies and is unique to each upper\lower pairing. Every manufactured part is inspected to within manufacturer allowable tolerances. While there is a remote chance your vehicle was delivered with virtually perfectly matched ports, it is far more likely that they are mismatched within allowable tolerances. It is also possible that your upper may be at the + extreme of allowable tolerances and your lower may be at the - extreme of allowable tolerances. This would be the worst possible case, but also one where port matching would result is greatest improvement. Your machine likely falls somwhere between perfect factory match and worst possible factory match.