For all of those who have installed the new cast plenum.......your opinions on ease of installation, performance gained (subjectively and objectively)

BTW, I did the RTV Hi-temp Gasket sealant modification that Crawford recommends to avoid engine coolant leakage. VERY VERY easy to do. I didn't know if mine was faulty to being with but I did it anyway just in case.....the RTV sealent was $3.95 at NAPA.
Here's the fix link:
http://www.crawfordz.com/support/Co...Leak_Issues.pdf

Here's the installation instructions:
http://www.crawfordz.com/support/PlenumInstallation.pdf

I did remove M2 and M3 metal brackets to avoid it being caught between upper and lower plenum but I reinstalled it after installing the Crawford plenum. You relly don't need to cut the plastic wire ties from M2 and M3, just unscrew the brackets and move it out of the way. After making sure the plenum has a tight seal without any obstructions, reattache M2 and M3 with the wire loom still tied on.

My take:

INSTALLATION: easy, took about a couple hours.
**Tips:
1. don't drop bolts, nuts or RUBBER NIPPLE into the engine bay. I didn't but could have easily done so.
2. DON'T DROP throttle body GASKET into engine bay when you unscrew the throttle body from the plenum intake.
3. DON'T forget to check the plenum gasket is still there when you change to the new plenum.
4. Again, I didn't need to relocate the wire loom like the Crawford instructions said to do, but I did need to unscrew M2 and M3 meetal brackets temporarily.

Subjective results....
More giddy-up on acceleration through lower and mid-range RPMs. "Less restrictive acceleration" if you know what I mean. Its hard to describe....acceleration seems easier and looser to stomp on the pedal. Don't have access to a dyno so don't know objective gains....sorry.

Anyone else.....?

doc

 

I installed mine last week. I removed the M3 bracket as it was touching the plenum, but left the M2 bracket. Install took a couple of hours as well, the hardest part was removing and putting back the throttle body trying not to lose the gasket. There's not much room to work in that part of the car so it took time to loosen and tighten the bolts. I also did the RTV gasket maker myself which was quite easy. So far no issues and my butt dyno says the car pulls harder, but it could just be in my head :P

I may get a dyno sometime, but I don't have a base dyno to compare against. All in all, I'm pretty happy with the results. Does anyone know if a 350Z carbon engine cover will fit in the G35c engine bay with the Crawford cast plenum in place? Not a big deal, but wouldn't mind a little dress up.

 

i installed my cast plenum a couple of days ago. i thought i went through the directions well enough, but when i went to start her up, a very loud squeel, and then it died! i checked everything, at least i thought i did, but i called doug to make sure.

like an idiot, i wanted to shortcut the instructions and didn't bother removing the M3 bracket. BAD MOVE! turns out it actually does, ever so discreetly, get in the way between the upper and lower plenums so i got that out of the way, torqued the bolts to around 200in-lbs (17ft-lbs) as opposed to the 45-61in-lbs by the factory, started her up and everything worked fine

after driving for a couple of days, i can say that there are no coolant/vacuum leaks. however, upon installation, one of the fittings was about 1-2mm smaller than the vacuum line. it kid of worried me, but it should be fine. after checking it for a couple of days (driving for several minutes in the middle of the cali sun), it seemed that it was fine.

you could defiitely HEAR a difference, a little throatier (my wife says it sounds angry). but as for FEELING anything, can't really say that i do. my butt-dyno is not calibrated to the amount of money i spend on a mod, so it looks like i'll have to take it to a real dyno to find out. other than that, i was pretty happy with it.

 

I am waiting to get mine back from the powder coater (hopefully tomorrow). I took my G for a baseline a few weeks but I don't think I will spend the money on the dyno until I get the cats, y pipe, and exhaust on. We shall see. As an FYI I dyno'd 232.7 to the rear wheels on a dyno jet. It's a 03 6MT with Z tube and a K&N.

 

I installed my new Crawford cast plenum yesterday on my stock G35 6MT coupe (except for a K&N and Z-tube) last night. The installation took me about an hour and went very smoothly. The piece is very high quality, Crawford has done a great job producing a high quality product. After warming up the car and checking for leaks it was time to take it for a spin. The first trip out of the garage is always fun...anxiously awaiting the drive to see if the new part has really made a difference. Usually what happens is one of two things: the anxiety in your stomach either turns into a big grin if the results meet or exceed your expectations, or it turns into a sour feeling if the mod is a disappointment. Well, this one was the former! I was very impressed with the feel of the car! No loss of torque down low (NONE) and the car now pulls like crazy from 4000 rpm to redline. I will be taking a trip to the drag strip this weekend to get a better idea of the true impact, but I assure you the car is much more fun to drive now. IMO this is a GREAT mod and I definitely recommend it! I plan to add Crawford cats soon to take advantage of the new found deep breathing ability.

 

hey lou, may i ask what bit you used to cut the cover and around what speed. don't really wanna melt the plastic and want it to be a nice clean cut. thanks in advance.

 

I reinstalled the stock/uncut cover on my G35 coupe.

 

On top of the plenum??? I thought it wouldn't fit...

 

I just bought and got a plenum installed today from DaveO, editor of SportZ magazine, real A-class kinda guy. I got a V5 plenum powdercoated black and polished on this inside to keep it smooth and reduce turbulent air flow. He cleaned out my cylinders and reset my ecu. At first I didn't notice as much gain as I would have wanted but I expected that as I was in an altitude my car was not used to,it was 105 degrees and my ecu had not been fully adapted to the new plenum. After driving back home I felt a difference in that the engine accelerated easier, and it sounded a lot more throatier. Hopefully my butt dyno is not influenced by the amount of $20.00 bills I handed to Dave.I plan on dyno'ing the car after I get the UR crank pulley installed. Overall pretty pleased with the mod and DaveO.

 

Thanks for the kind words Aaron. You sure have a great looking (sick) Coupe. Your correct in that the 2650 ft altitude and 105 degrees ambient temperature sure impact performance. If your 03 ECM is like mine it will take a little while to adjust to the increased/balanced air flow. Keep us posted.

By the way, there's a common misunderstanding in the torque specs for the plenum. The factory specs for the 16 bolts and 2 nuts that connect the "Intake manifold collector (upper)" - the plenum - to the "Intake manifold collector (lower)" are 9 - 10 ft-lbs or 108 - 120 in-lbs. The same value is specified for the 8 "Intake manifold collector (lower)" to "intake manifold" bolts. The 44 - 61 in-lb value commonly quoted is for the two guide studs when screwed into the lower plenum. As noted above, the 2 nuts that go on them are also torqued to 108 - 120 in-lbs.

 

Ok, can anyone explain the differences between getting a new plenum outright and just adding a spacer to the stock plenum?

Also, do CAIs connect to the aftermarket plenums just as they would the stock plenum. I ask because, I'm getting my CAI tomorrow, and I'm wondering if I decide to add a new plenum afterwards, will have any problems reattaching the CAI?

FWIW, I'm getting an AEM CAI on my '04 G35c.

Thanks

 

the intake attaches just like it normally does.. straight onto the TB

 

Hmmn wonders about real results, does Crawford provide any insight as to what acutal gains are gotten from this mod. And how does it affect the 05 6mt?

 

Do a search - there's about 200 threads on the subject and you sure can always count on Doug at Crawford to talk turkey with you and help you determine what the 05's are doing with his products. The best search may include the terms, "bench flow testing". Doug has been around for a while and didn't get there by having crappy no gain-products.

 

the concept of a plenum and a spacer is basically the same. our stock intake plenum has such a sharp angle on the forward end of it, that it makes it quite small. a spacer or aftermarket plenum, takes this sharp angle away, making the forward part of the plenum larger.

oh, and yes, the CAI will connect the same way to any aftermarket plenum you get.

if you want the theory and all of how it works, do what he said and talk to doug. he'll be more than happy to explain it all to you. hope that helps!