rotorwiki

I've got a spare set of irons I'm going to get a good port job done on before I dive into my "production" irons. I've been staring at my templates for a while now... a bunch of howtos on porting... And here are the ports I've come up with. So far just the secondary/aux ports... I probably won't end up doing much to my primaries at all... just cleaning those up.







I'm thinking I can go a bit furthur on the aux ports, but no template I've seen goes out that far... whats the reason for this?



Thanks in advance for your advice.

rotaryinspired

I have ran a port similar to what you have drawn out. Car ran good. Dont do a lot to the primaries unless you mind it doggy down low. But who drives there?

rotorwiki

So, one thing I was thinking.... The secondaries are pretty much always open right? So, how does this affect your low band? Seems like leaving the primaries small and the secondaries big is counteractive. Perhaps less so than doing both the primaries and the secondaries.

rotaryinspired

no the secondaries are not always open. I also ran the sleeves in this motor. I just modified them abit. Some will probably say the closing on the 5th and 6th ports are too late on the plate I posted, but like I said it ran very good when I drove it.

rotorwiki

Looking at my manifolds, the butterflies open at the same time for the primaries and secondaries... or atleast barely delayed secondaries.. I can't imagine that the secondaries are closed for much of the RPM band. But, I could very well be wrong. It happens frequently.

CGeek2k

The secondaries are essentially always open, except for under 5% throttle or something like that. The upper auxiliaries are sleeved to open only over about 3500 RPM.



For my rebuild, I got a center housing from a turbo car and used that as it was, except for cleaning up the casting. The secondaries were opened up a little, mostly inward, I didn't change the timing much. The auxiliaries I opened up a lot. I'll try to find some pics of my ports.



Edit: Here they are:

[attachment=42372:Front_port.JPG]

rotorwiki

How were those ports to drive? Those are some crazy aux ports... I would imagine the intake would start blowing back out by the time it closed....

CGeek2k

They are a lot of fun. I've put about 26,000 miles on that engine daily driven. I like that if I granny shift all the time, I can still get 23 MPG, but if I open it up all the way, you can really feel the kick when those ports open. There might be some intake reversion, but I don't know an easy way to find out. Since they only open at high revs, the gas momentum should help that out a bit. They definitely have more power than the stockers though.



I still need something to help the flow in the sleeves. Are those Pineapple inserts still around?

rotorwiki

Yep, if you want to pay 50 bucks for them.