alright...i bought an extra head about a week ago and im slowly in the process of porting and polishing it. my goal from doing this is to get my car to run strong up to 7200 rpms instead of dying off at 6500 like it does now. im not going for an all out race port, so all i did was gasket match. im only done with the intake side but i also gasket matched the bottom of the intake runners on the intake manifold. i want to wait until i get my turbo manifold in that i ordered to finish the exhaust side, but that will get gasket matched as well. im also porting the throttle body inlet on the intake manifold to 60mm to match my jeep tb. i didnt really port anything out before the valve seats, i just cleaned it up with 80grit and got rid of any imperfections. now the question is...is this enough work to make my engine run strong to 7200? won't this make my turbo (when i get it) spool quicker as well? thanks
-adam

hey eclipsestyle, wanna know how to work a cylinder head thats going for turbo? listen up =). When it comes pressurizing the intake mani, there really isnt anything that could be done with machining the intake side. Turbos cause sooo much turbulance, it doesnt really show up on the track or dynos that much, if not any, heck most 10 sec turbo cars still have there intake side untouched (was it bill hahn or someone else that ran 10s on a n/a stock head with turned turbo? something like that). Valve jobs, polishing, matchporting, really only applies for all motor, cause they use atmospheric pressure! they need to reduce turbulance to get air in as much as possible. The machining work you should be concentrating on is the exhaust side, cause of the amount of gasses and heat thats left over, (remember intake to exhaust ratio, there different for N/A's and Turbo cars, turbo's having bigger exhaust ports). Turbo's have soo much heat potential, causing more exhaust gasses, needs to get out before the next air charge comes in, which brings us to backpressure. Ever thought about a little kids pinwheel, remember those? they turn when the wind blows? ever put your hand behind it? yup, it stops. If you want to spool quicker, open up the diameter of the secondary exhaust pipes (after the turbo) if you want quicker spool. Nos could work well with that head you just did, intake sounds like it could work well for better airflow, and nos still uses atmospheric pressure on the intake, so work on the exhaust, then when you got turbo, it would benefit greatly for the exhaust side you worked on. Just giving you ideas before you do anything else. Turbos are wonderfull cause the best way for them to make easy power is getting the fuel to match the upgraded turbo and tune it right and opening the exhaust (one guy I met whos from dsmtuners at a In and Out meet at Baseline in AZ, hits 13.5 with just fuel matching and tuning on his 1g tsi, stock turbo, street tires). Good luck dude! hope everything works out for ya!.

Here's a good link about head porting - http://www.sa-motorsports.com/diyport.htm

A descent port job should help airflow - whether you're turbo or not. Don't hork it out, just get rid of the sharp turns. Air doesn't like to take sharp 90deg turns, it more likes a nice smoooth turn. There is one thing that will help the most in the revving department though - cams. Consider buying a good set of aftermarket cams. There are qutie a few threads in the performance, turbo, and advanced-tuning section about our choices. The stock cams fall flat on thier face right around 6500 like you've noticed.


95 Eclipse RS : 5 speed
15.7 @ 87.9mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

I am pretty sure that you wouldn't port a head for a N/A application and a turbo application exactly the same but here is what I did.

First I gasket matched the intake to the gasket I am using. You want to be sure and have the gasket lined up with the bolt holes at all times or you will grind the holes wrong.

then I ran a grinding stone throughout the port to knock down the casting flash. I actually had a very big chunk of aluminum in one of the 1st cyl intake ports that closed the port about a quarter of the way.

I then flipped the head over and blended the seats to the port.

after that I ran a piece of 180 grit paper through the port and worked out any other imperfections by hand.

on the exhaust side I didn't gasket match it. having a step in the exhaust port will help keep some of the exhaust out when the valves overlap. this is what a well respected ford engine shop said anyways.

Other than that I repeated the grinding work on the port the same as the intake.

after I was satisfied with the dremel work, I used the 180 grit, then 240 grit, and finally 320 grit paper in the exhaust. I water sanded the ports with the 240 and 320. the ports are extremely smooth and you can actually cut your finger if you run it around the outside of the port.

thanks for all the info guys:thumbsup