Ive already made the decision not to sell the setup we are using on my car, as frankly, it's too time consuming for us to do. I also frankly fail to see the market for it. I chose to do this purely for my own enjoyment and to really get us intimately familiar with maximizing the NA potential of the car. There is alot we have learned about the engine in the process, and a bit more testing to go. I finally got my hands on the stock piston today, so we'll be able to make (or build) or final cam selection. Then it's time for the install on my car, install the ecu, figure out if I need to address the fuel side of things and do the tuning. Still have alot of work to do before spring

As for the polishing, you are right - the whole point in my setup was to minimize pressure drop, eliminate the dead spots (where air can just sort of hang out, and move slowly which reduces overall volume), and increase velocity through the intake path

 

well, then, detailed DIY please!!!

oh E_K's car, he did lots of polishing and apparantly gained more power than most of his mods did at the time.

but ive also heard that turbulence is good to have so does that mean that excessive polishing would be bad?

 

not only diy, but please share your findings so that others may benefit. Only by increasing the knowledge base can we break the locks that keep us from making more na hp.

 

Tell it to Tony, he claims you don't get nada at redline. hardly nothing. zero.

 

This folks is why this man is my "tuner." Adam is more knowledgeable than anyone else I've spoken to in regards to performance modifications for the Z. Give this man your business not only because he is a sponsor of this forum, but also because hes part of the 1% of the people on this forum who knows what the hell they are doing.

P.S. Adam this project is not "purely for [your] own enjoyment" as you put it, I am also enjoying this as well. And I know I'm getting a ride in that beast come spring.

Kwame

 

well thing is I did not know squat about the car when I started with it, as its my first naturally aspirated car in about 4 years (last was an S2000), and the first I have ever played with engine wise. But through the right contacts and the expertise of the engine builder we have used for 10 years now, is how I've learned....and continue to learn. It's been an expensive process for sure, but I think it's going to pay big dividends in terms of the smile on my face once it's done

 

i too respect the expertise and knowledge that adam has given to this forum. he seems knowledgable in all areas of the car including engine, suspension, wheels/tires, etc... i have never heard any negative feedback from adams customers so that says something right there.

just wish he would share a little more on his latest setup

i am interested in the plenum mostly...don't really want to go internally more than that. if there is more efficient flow to be had with just stock internals that may help some of us who don't have the budget to do a full bore engine rebuild. i suspect though that all of these are in relation to each other so your setup will be unique. however, i will patiently await what you do decide to share as far as the plenum goes...

 

as for the too much polished question...

there are basically two types of airflow... laminar (streamlined) and turbulent (rough)...

Wind tunnels have shown that air flows better with a small surface area of turbulent flow where the air touches metal for example or whatever the surface may be...

the rolling turbulent air around the edges creates almost the same thing as you would consider grease (not actual grease) but it allows the laminar air to flow easier..

I'm sure thats a dumbed down version... but its something i learned in college.. The best way to get good airflow is to have an equally spaced design allowing for symmetric airflow disturbances making that slippery layer I was talking about...

Its the same reason why golf *****, footballs, etc have dimples in them... to help laminar flow

 

I agree with the discussion on air flow characteristics. Having a certain amount of turbulence in particular where the fuel is injected is traditionally believed to help with fuel atomization. There's one port/polish company that intentionally makes dimples in the intake runner in the cylinder head. That's why most people don't polish the intake side of an engine to a mirror shine. However, they usually do on the exhaust side to help reduce carbon buildup.

On my car, the intake side was polished to approx 320 grit smoothness. The casting imperfections where removed in the lower plenum and intake manifold. Everything was portmatched, except for the junction between the upper plenum and lower plenum.

In my spacer thread, I briefly talked about my dynos. In the dyno day in September, the car put down 254, 249, and 249 at the axles (dynapack, yes, I know that the numbers are higher than the dynojet). With a bit more refined polishing/porting work on the exact same dynapack, it put down 260, 258, 259 (3 consecutive runs). It also had rear rotors that were 2 lbs heavier in the second dyno. Ideally, all the runs would be on the same day, but I've been using the same 76 gas. Also I can't polish and port match in 5 minutes between runs. I think there are some gains that can be made, how much so I don't know.

 

Message deleted, read your PM kiddo.

 

I know that this is an old thread that ran dry long ago, but it is still a hot issue. Hydrizine is selling lower plenums with some degree of porting that seems to produce results. So was anything learned in any of these experiments? Was the project a failure?