teg_fan

So Im getting ready to do my na setup finally this spring contrary to popular belief and of course I am faced with the intake manifold decision.

first of all, if you havent seen my planned setup....

ctr pistons (12.5:1 cr)
skunk2 stage 2 cams
skunk2 valvetrain
jdm itr 4-1 header
2.5" cat
greddy evo
cam gears
flywheel
310 cc injectors
etc etc...

What I am lost on right now is what I should do in the intake manifold department. I was thinking about going skunk2, but I wanted to see if I could keep some low end and mid range despite the fact that my setup is made basically for high end, so I thought about keeping the gsr intake manifold. Does anyone know any companies that port intake manifolds? If so, do I want to get the im ported just where it meets the head or should I get the whole thing ported and get bigger butterfly valves (if possible)??? And finally, will a ported gsr im flow just as good as a skunk2 in the high rpm ranges? Any help or suggestions are welcome.

dubcac

My roommate had a ported GSR IM on his LSVTEC. It was ported all the way through, and where the butterflies are. He didn't get bigger butterfly valves though. As far as flow, I think the skunk2 IM would probably flow better at high RPM than the ported GSR manifold. Why get components that produce high end power, and not match it with the intake manifold?

teg_fan

well, as Im sure you know, when going na on a 1.8 liter 4-cylinder pretty much your only hope for power is high in the rpm range. But, I was trying to see if it is possible to retain the mid range and through porting the gsr im-also flow like a skunk2 in the high rpm range. Did your friend take the butterfly valves out? If he left them in, then air must have been slipping past them previous to their opening at whatever rpm. Wouldnt that sorta mess up the low and mid range?

Snoopy

if you want better midrange get some different cams. i hear the new skunk pro1's are a very good street cam with good midrange. you can find dyno sheets all over h-t for them.

teg_fan

ya, I heard the pro-1's are puttin our good numbers. Perhaps I am asking too much with this whole gsr im porting deal. I guess planning on having a 9k redline there is no hope for increasing midrange with just the im. I was thinking about getting pro-1's but I might be getting a real good deal on some used stage 2's. You think I should just suck it up and get the skunk2 im snoopy?

Snoopy

if you want the easy way out, get the skunk2. if you're up to a challange, stick with the gsr mani and get it ported.

Snoopy

a little o-t here but i just did some checking of your setup and with those pistons you're going to be very close to 13:1 cr. i hope you have a good tuner. what do you have for engine management?

teg_fan

I plan on getting a thicker head gasget to get me down into the mid 12's. For management, initially its just goint to be tuned using a wideband and using some software that "the guru" has on his laptop ( to chip an obd1 ecu). Once tuned I plan on probably getting neptune from jeff. If you have any suggestions in the management area, they are most welcome.

dubcac

You're gonna need more than just a chip to tune that. You're going to need neptune/hondata/uberdata, or something of that sort. As for the manifold, my roommate left the butterfly valves in. He kept the midrange even though they didn't quite fill up the entire runner, and top end improved a bit...but it wasn't as good as the skunk2 manifold he previously had.

teg_fan

ok, looks like its gonna be skunk im then unless I get some good feedback from my friend that knows a porting shop. The initial tuning will be with a wide band and a chip becuase thats what is available where the engine is being put in the car. When I get the chance, I will take it to jeff to tune it.