MurphysZ

iTrader: (6)

I have my upper and lower plenum off of the car to finish polishing them. I was thinking about the SSV plenum and how it looked with the tubes running directly into the lowest plenum piece. Why can't the lower plenum be shaved out? Instead of porting each of the the runners, take the SSV approch and get rid of them all together. Maybe I don't know enough about what I'm talking about but it seems the SSV gets really good gains and all it appears to do is cut out all of the channels our plenum has inside of it. All our plenum is an air chamber with channels made out of cheap cast aluminum, tell me what I'm missing? Whats are the channels for? Why are different sizes? What would happen if they were ground out?

MurphysZ

iTrader: (6)

I cut into the lower plenum today. I cut the tops off of the runners, ported out the inside of the runners. I'll post pics soon they will show how much was cut out. Butt dyno shows a gain!

godmans

iTrader: (10)

The SSV gains are not that obvious in N/A cars.. moreover if you just port the **** out the lower plenum, it is indeed even worse than the SSV, since the SSV at least have some individual runners while porting out the lower plenum (I think you meant gettting rid of them like how one guy did it in another thread) will leave NO runner length in the lower plenum.. where hp/tq will not be useable in normal rpm range and gain ONLY up top (by how much? I dunno..you can try to wait for the dyno of that guy)

ZU L8R

iTrader: (84)

you mean like this? audiblemayhem did it and is gonna try and dyno it pretty soon.

MurphysZ

iTrader: (6)

YES! I cut part out but decided not to take it all the way for the first time around. I only had today to work on it and the car needed to be back running at 6pm. The work is crude at best but I knew if I screwed it up, I could get another one cheap.

ACEMAN

iTrader: (29)

Shorter runner lengths = more high end HP but it also could move your peak HP to a higher RPM, maybe even above redline.

Longer runner lengths = help with low RPM torque but higher end HP could suffer.

Its all about finding a happy medium. Im curious still, to see how audibls's cut away plenum works out for him on the dyno.

Later
Aceman

MurphysZ

iTrader: (6)

It's funny you say this....that's seems to be exactly what my butt dyno tells me. I cut the runners even with the middle one, straight across on both sides, and ported out the inside a little bit. I also cut the tops off of the outer 4 runners. I filed most of it out to smooth it down. HACKSAW and files and a dremel....5 hours later I had the car back up and running.

ACEMAN

iTrader: (29)

Get some pics up

So you live right above Baltimore? You been to the dyno yet?

Later
Aceman

MurphysZ

iTrader: (6)

No, I haven't been on a Dyno yet but, I will be looking into scheduling it shortly. Pics will be up on Monday, like I said, expect to see some ruff cuts. I had a dremel, some files, a flap wheel and a couple of hours, these will not be photos of a 2 week project. I have to do more but the car is my daily driver. I think people are overthinking the lower plenum, but that's just my opinion, it's not as delicate as people think. Tomorrow I drive it Ocean City, about a 3.5 hour drive, so I'll be able to see it through all different driving conditions. So far the difference I feel is at about 4000 RPMs, it pulls much stronger. I meet up with another member on here, Momo 305Z and let him rev it a few times, he said he could see where it jumps at 4000+ rpm's. I cut the side runners straight across and cut the tops off of the 4 outside runners. I am still goining to port it out more. I keep you posted on Dyno results as soon as I get it scheduled.

johnlotusboy

iTrader: (1)

If you want to know volume of runner differences you can duct tape the port hole at the gasket flange and the pcv holes inside the runner. then you stand it on edge in the sink and pour water into the runner mouth 'til full.
I found the volume to be equal thou the length seemed different. The cross section of the runner seem the same at both ends. With all that said I want to cut about 5/8" or so off all the runners for just a little higher rpm/frequency.
I want half way between the factory two styles of lower plenums with a smooth polish on the runners.

MurphysZ

iTrader: (6)

I drove it for about 8 hours total today mostly highway driving, the power seems to has increased in the 4K rpm range. Doing 70 + most of the day, I ended up getting about 21.7 mpg if anyone cares but,there were some unneeded accelerations though out the day. My idle has increased to 1K rpms and sits solid, no lope/up and down reving at idle. When I press in the clutch it's dropping to 950 rpms and then coming back up to 1000 and stays. Pics will be up tomorrow of the cuts I made, I plan on porting out the runners in the near future. I have a Sun Hyper Force on the way and then the car will be Dyno'ed. Sorry guys, this will be the first time on a Dyno so there are no previous # to compare it to. The best comparision I will be able to give is now vs. after porting.

Audible Mayhem

iTrader: (48)

ok guys.... screw it, it is going in tomorrow. i can tell you right now murphy if you dont have any ecu that you could have tuned that to then you lost a lot of power. i tried this about a year ago and i am just now getting around to get it in my car. i lost a lot with it in my G sedan without tuning it. i have a utec now and will put it in tomorrow. i have an acelerometer that i can see how many forward Gs i am pulling and at what rpms.


i just hope my peak hp doesnt move too high....

results tomorrow... i will be on a dyno on thurs. if i think it pulls harder then i will dyno it on. if i dont think it pulls harder than the stock on will go back on for the dyno...

lex350

iTrader: (16)

sub

MurphysZ

iTrader: (6)

Here are the photos of the cuts I did.....as you can see, I'm not working out of a machine shop, this is straight up hillbilly modifing.The first pic is before any cuts or filing was done.

MurphysZ

iTrader: (6)

And a few more

MurphysZ

iTrader: (6)

And a few more I had to resize smaller

MurphysZ

iTrader: (6)

With this project, it's all based on guess work right now. I welcome any feedback from anyone that is doing something like this or that can offer any usefull knowledge. As you can see, I still need to port out the runners, and I plan on smoothing things down more. The pics show the work I did in about 5 hours, more time will be spent but the car is a daily driver.

In the pics, you can see the pieces that were cut out to get an idea on how much material was removed but there was twice as much in shaving on the floor from filing and sanding everything down.If nothing else, I added air volume!

key

Why, after all the work done with some of these intakes, does it seem like nobody removes the letters that are cast into the intake right in front of the runners?

key

Something else that I find interesting is that the runners on these intakes are right next to each other, with regards to the air horns. It seems that a runner could be taking air from the one next to it, and then visa-versa when the other runner begins to draw in air.

Do you have any pictures of the intake hat (upper plenum).

MurphysZ

iTrader: (6)

LOL....they are actually difficult to get to, I tried. There are walls on all 4 sides, I have to get a new 4inch flap wheel and maybe I'll have the room to get them. Not seen in the pics are the polishing work I 've done on the front engine cover and upper plenum. I went as far as cutting off tabs and filing them down.