I believe all 06 ATs were 6 speeds. One reason I got an 05 4 speed was because I could get it for dirt cheap, I imagine because it was a leftover and the 06s were coming out soon with the better engine and tranny.

 

Absolutely fabulous information. Very appreciated RG.

 

I recently removed mine (to fit the RB duct) - Agree that it is for noise control but it does actually flow more air when it opens .

Closed : sleeve only supplies air
Open : sleeve + secondary duct supply air .

 

that second post kills me every time

 

*sobs* i just wanna cry!!!

 

This doesn't mean give up on the engine. Even the 4 port makes more power than any 13B street engine did without a turbo and I've seen completely stock 13B's boosted to over 600 rwhp before. You are merely starting from lower on the totem pole than the 6 port engines and will ultimately have less total performance potential.

 

Just curious RG, what do you think about the higher torque output the 4 port has? Why is that? How do you think it will effect boosting a 4 port? Any ideas on why Pettit's charger produced higher gains (though lower overall numbers so far) than the MT engine?

Obviously there's some uncertainty here since there aren't many boosted 4 port renesis engines, but I'm interested in your opinion.

 

The port timing is more suitable for lower rpm power than the 6 port. The 4 port is still different than just a 6 port engine with 2 less ports. There are port timing differences between them as well and this affects powerband. The intake runners are also longer which is also better for lower rpm power.

 

another issue is that there will never be as much research put into the 4 port because the new autos are 6-port.

i guess there are some other 5-speed 4-ports in other countries

 

Here's another thing I'm wondering. How will certain power addings mods affect the 4 port auto differently? Meaning, how would something like a midpipe affect a 4 port compared to the gains on a 6 port? This one has me thinking a lot.

 

Yes! very GOOD question!

I was thinking of getting one.

 

That definitely makes me want to keep the 4 port over upgrading to the 6AT. I don't have a problem with the power the engine makes up high, it is the off the line punch that i would like to improve. Hurry up, Petitt...