n1cK, I guess the Dyno next week will tell the tale, I have my previous benchmark without the Crawford Plenum so I should have the real scoop. I have heard of leak issues but I'm running so smooth and strong I can't see/hear/feel anything wrong. I've made several runs WOT and putt puttin and it's a beast. If I had leaks I think I would hear it or it would bog at WOT, neither is happening. If 2 gaskets makes the seal fine by me. I installed it yesterday and sent my plenum back to Crawford today I feel so good about it....Rod

03 5AT Cpe-Laser Red-Premium-Aero-Tire & Wheel Pkg-Splash Guards-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

I can't quite figure out from your description what improvement you noticed from the plenum install alone. When you said it's a beast, did you mean just because of the plenum or because of all the mods cumulatively? In any event, how would you describe the change, if any, from just the plenum install?

I have a plenum ordered and plan to have the mating surface machined flat before trying the install. Any thoughts?

 

exagorazo,

I was waiting for the post plenum dyno results this week to go through all this but I'll tell you what I "feel" (butt dyno) so far. The z tube and k&n went in at the same time; there was a more agressive (lower exhaust note) sound above 4000rpm. The car felt slightly faster. At a certain time in the morning on my commute I need to go about 1000 yards to make a redlight (from another redlight) crossing a large intersection. Pre z tube I had to floor it on green to travel the 1000 yards to the the next light while it was just turning red as I'm going under it. Post ztube/grounding gear I'm half way to 3/4 on the gas and I'm under the 2nd light while it is yellow. That tells me I'm a little faster. Haven't run that route post plenum.

Grounding gear came next and that mod made the MM and AT shifts feel faster to me (there are those that disagree but that's my assessment). I don't feel faster with the grounding gear, I do feel "smoother".

I dyno the day before I install the plenum (just this past week) with ztube, k&n, and grounding gear. 3 runs; every run was .7 or higher so I'll round up: HP 225,226,229. Torque 225,226,214. A stock 2004 AT coupe at an Infinti dealer here in GA was doing 224hp and 219 torque; a previous post NEFFSTER made showed a stock 2004 AT with 228hp and 217 torque so that is all I have to comapre to. One set of numbers says the ztube etc is better one says it's worse/the same; I guess this week will settle it.

Now post plenum the butt dyno feels definite torque increase on shifts, speed seems to pour on command and the exhaust note has become "mean". We will see what the numbers say the end of this week. Of all my mods the "performance" one on feel alone is absolutely the plenum.

I have read the leak horror stories and can only say that I have not experienced any. I did do the double gasket as Crawford recommends. I hear no whistle and no bogging at WOT or moderate throttle so I put it on Friday and sent my plenum back to Crawford Saturday. I think the gasket takes care of any issues with the surface and if there were problems I'm sure Crawford would make it right but that is your call.

Hope that this made better sense.....Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5

 

Rod

Thanks a million for the information - much appreciated. I must confess that the numbers baffle me. My guess would have been a considerably greater improvement on paper.

I'ver installed the Popcharger, Z tube, Stillen grounding kit, DC Sports stainless headers, Borla true dual exhaust and TS ECU reflash. The reflash was based on having the plenum already installed (even though it isn't) so I wouldn't need to go through that drill again.

My subjective impression is that the mods made the car much faster, by at least a third or more. All the numbers I read tell me that I am out to lunch and I find myself wondering if much of the apparent difference is illusory because of the increased (but sweet) Borla exhaust note.
After the plenum install, I hope to do some testing to see the end result, but I have no base line for comparison.

 

exagorazo, I'll post my before and after results this week and we will see. I'm sure with those mods your better than stock but a dyno post mod does give piece of mind and you can only butt dyno so far ...Rod

03 5AT-Premium-Aero-Tire & Wheel Pkg-Splash-Z tube-K&N Filter-32% Tint-10 wire Grounding Gear-Crawford Plenum Ver 5