When do they open up? And.... doesn't the 5 port switch over to the 6-port sometime between rpms/shifts? Or am I getting this switched around somehow?

 

they fully open at 5500

 

*3800RPM

I think you're thinking of the VDI.

 

They start to open just under 3K rpm. I am a little confused about the latter part of your question though. Switching between ports??? The Auxilliary ports open and close at the same time.

 

dumb assed question......
what is VDI? i keep hearing people talk about the VDI. arggg

 

Hey dude,
Chill out on the cussing. You are in the company of a lady. A respected one at that. Now go do a search from the search function from VDI and you will have your question answered.
regards,
Charles

 

Maybe I am mistaking it as the VDI - but I thought, when asking if the 5-port switches to the 6-port.. like... the 6-ports don't open up until a certain amount of RPMs, and once that hits, the 6port opens... I didn't know they open together once at a certain RPM..

So, does it work the same way once you wire open the 5th and 6th ports? Or does it do something completely different than now? I know it's different from the s4 and s5's...but, I dunno. I'm not too smart into this stuff yet

Oh...and peacekeeper, thanks. Ha, the language wasn't necessary, but I understand his frustration and the confusion of these abbrevations, I still am not that knowledgable in some of this...

 

When you wire them together, they are always open. That gives better flow at lower RPM ranges which degreases the velocity of the air flow in the lower manifold runners which causes loss of tourque in the lower RPMs. If you drive like me, you dont notice bc its always past 4500 The difference bt series four and five is the direction of which the ports turn to be open i believe. Hope this helps and you'll get it soon dont worry.

 

aye, sorry bout the language, but all the gi chicks i know are worse than me...........any way. i dont have a vdi. i still dont really know exactly what it is but i got the juist of it. i say pineapple ramps and wire the ports open. only make sense. to me any ways. and itll work better after you bolt on that turbo!

 

I wrote up a thing or three about the auxilliary port valve system:
http://www.zaxjax.com/howtos.htm
If anyone finds anything wrong let me know, buy I think its all good.

I think this is what you want- how it works:
http://www.zaxjax.com/APVS.htm

 

hey zach, if you ever see a pearl whit 85 with a TII hood scoop runnin around your area dont even think about it. its not me but i guy i know. im not givin away any secrets but ill just say ive got money that thares not an 2nd gen that could walk him. i was just thinkin, the aux ports are kinda like using a vaccume secondary holly ona half bridge, kinda. whe way it looks you cant reallu port much on the 2nd gen n/a engine, well not linke a 4 port any way. i think for allout power you could use a TII set of plates and intake with the rotating assy of an s5 n/a and port the hell out of it. i bet it would be prety streetable. may not have a huge amount of low end but driveable........

 

The 5th and 6th ports start to open at the same time and you want them working properly for the best streetablity. Like rxseven and darkwaveboi said they start to open at ~3K RPM and are fully open at ~5500 RPM.

The VDI is on the S5 intake manifold, Silver88GXL talks about this in his intake swap. See the sticky at the top of the 2nd gen specific page. I'm not going to even try to explain it seeing as i don't fully understand it myself. but check out Silver88GXL's website, he has a great writeup about the intake swap.

 

hey i got a quick ?. if my 5 &6 ports arent opening, would i still be able to take a 97 240sx with mild hp upgrades, headers exhaust ect?

 

Ok, tell him to come to the next autoX ----> www.vmsc.org.

I did meet a guy at an autoX (he didn't run) who had a 1st gen w/ a 13bt and all kinds of goodies (pearl white, TII hood, 17" wheels). Maybe that was him?

As far as your porting combos, the 6 port system gives you the increased port timing without losing low end torque. You can still port the center housings as you would a 1st gen and gain a little more (aproximately 10-15%). http://www.zaxjax.com/street_ported_side_housings.htm
In other words, I think its best to keep the stock housings in favor of the low end torque.

 

"hey i got a quick ?. if my 5 &6 ports arent opening, would i still be able to take a 97 240sx with mild hp upgrades, headers exhaust ect?"

dont even try.

 

You might beat him or be even off the line and up to 4,000 RPMs, but after that you just won't pull enough. Before I fixed mine, the car wasn't pulling very hard after ~5K (almost felt like it wasn't accelerating anymore; the horsepower curve was just flattening). Now that I've fixed em, it just keeps pulling harder the farther I go up in RPMs. It feels like a little bit of boost past 6K! I love it. You should definitely invest the time to fix 'em.

 

no way, think about it this way, if those ports aren't opening up you basically have 13B 4-port like those in the GSL-SE, add a few hundred pounds and you are really hurting for some power.

The best thing you can do for your engine is make sure those ports are opening smoothly it makes a world of difference; night and day.

 

Okay, well...why I ask is the fact that everytime I hit between 3k and 5500 rpm it hestitates badly. Sometimes it's not all that strong, but other times.. it's where I can't gain up in speed or anything as well as I should be.

I checked the hoses, and as far as i'm aware and what I saw - no leaks.

Could the hestitation be caused by the 5th and 6th ports not opening all the way?

I looked at some posts last night from the search, but can't remember what they were.... or find them again. blah, but yeah, why would it be hesitating between 3k-5500rpm?

 

The GSL-SE is a 6 port.

 

I don't think that is your problem

Let's put it this way, Have you missed a shift from 2nd gear to 5th gear?

That is exactly how it feels when you are trying to hit redline with closed 5&6 ports.

 

http://home.earthlink.net/~burntoast/3700.html

 

yeah, i'm getting all my facts messed up recently, the 13B 4-port was in early cars like the RX-4 and RX-5 right? and they reintroduced the 13B with the new aux. ports in the '84 RX-7.

 

Right.

I'm old school at heart, I have to represent the old cars

 

FELIX, you are SLACKING!!!

J/K

There was no RX5

 

The CD23C Cosmo was aka the RX-5.