This weekend, with the help of Filtor1, I installed the lower intake manifold off of a 6th Gen onto my 5.5th Gen motor. The upper IM (aka Collector) is different between the 5.5th and 6th Gens, as the 6th Gen has the EVAP system integrated into the manifold, where the 5.5th Gen does not. I have pictures of both collectors for comparison.

As far as the improvement: I was told by Filtor1 that the gain was noticable. He seemed to think that the lower end gained more than the upper end, but the gains in the upper end were still noticable. My girlfriend also noted that her neck hurt after riding along with me on the test drive.

As for the differences between the lower IMs: The 6th gen has 2 extra tabs on the outside of the IM, but that's more of a casting change. The internal changes were very very slight, but definitely noticable between the two.

As for the installation: I recently purchase an air compressor, impact wrench, and metric impact sockets, so installation was a breeze. I did not do a write up, but I do have pictures of the parts for comparisons.

As for the cost: I ordered the parts through Dave Burnette at South Point Nissan (888-254-6060). The cost for the collector (which I can't use but bought as a trial-and-error piece), the lower IM itself, the "TB pipe-collector" seal, the colletor-lower IM seal, and the "lower IM-valve body" seals (there are 2), were about ~$220 or so plus shipping. It may have been less, but it's been a while since I bought them.

One other thing to note: While I had the intake apart, I cleaned everything. It was pretty nasty too. The car is 2.5 years old, I am the original owner, and has had a Petro-Chemical Cleaning (PC Cleaning) every 6 months. I used an entire can of TB/Carb cleaner ($2 at your local auto store) on the upper collector, the TB tubing, the TB, and the lower manifold (even though I wasn't reinstalling it).

I can only assume that the gains were a result of both the change-over and the cleaning. The throttle response is significantly better, but it is known that cleaning the TB resolves that issue.

Pictures are available at my web-site in the Intake Manifold section.

 

props for the pioneering

 

Good shyt Studman....Cant wait to see a future dyno to verify some sort of power increase....if so the cost of parts are very well woth it

 

Subscribing. Very interesting and thank you for the info. Do you plan on dynoing? Also I'm not sure what relevance your girlfriend's injured neck has to this mod. Please keep such intimate details limited to the OT forum.

 

Sounds promising. Subscribed.

 

nice work studman

 

and the 6th gen part #'s

 

erm... honestly unless there is a signifigant change in runner length or diameter, i doubt this will make much of a difference. The greatest gain will be felt from changing out the upper collector, as I believe it is a completely different design than the 5.5 gen one. What specific issues did you have in making it fit? Could you post some pics so we get an idea of what the incompatibility is

 

Yes. I'm waiting to get some milage beforehand. It's been 100+ degrees here, so a dyno wouldn't be very accurate right now, even with SAE adjustments. It's supposed to cool off (and maybe even rain) in the next week or two, so hopefully we'll get back to our normal 89-94 soon.

The lengths were the same. The diameters changed, but slightly. If you look in the pictures, you'll notice a small bump in the IM on the 5.5th gen that doesn't exist on the 6th gen. While it's a very small change, it's still a change towards a larger diameter.

As a side note, there is still plenty of room on the manifold to port it out without reaching the edge of the gaskets. I'm attempting to locate a shop locally (or at least in the state of Florida) that can port/polish my old IM for me. I'm also looking into modifying the upper IM to see gains similar to SR20DEN's gains.

I would agree that the upper collector needs some changing, but SR20DEN has already proven that.

With the exception of the EVAP system, they are identical. The measurements internally and externally are the same. The only difference is the EVAP runner along the bottom (which has 6 very small holes into each IM runner).

The upper collector has a runner on the bottom side of it where the EVAP system connects. There are 6 individual plugs on the bottom of the runner. At the driver's side of the runner, a hole exists along with 2 screw holes. In order to adapt the collector to our car, you would have to fabricate a seal and a metal plate to cap off the runner.

I'll get them uploaded tomorrow or so.

The lower IM is 14003-7Y000 for the 6th gen Max.
The lower IM is 14003-8J105 for the 5.5th gen Max.

The collectors have different numbers as well, but as mentioned earlier, you can't do a direct replacement without some custom fabrication.

The seals and gaskets are all the same part numbers for the 5.5th and 6th gen.

 

Ahh, so this is what you hinted at. I can't wait to see what the humblemaker brings. Great job, it takes guts to jump on things like these

 

Great job setting this up. I do have a question though. Is it possible that Nissan put that bump there intentionally to help create turbulance in the air stream into the head which "might" help to reduce emissions, improve combustionn and give better overall fuel economy? Do we know that there weren't other changes in the '04 engine to compensate for this bump not existing there? I don't know the answers, but I'm interested in your thoughts . . .

 

wow thanks studman, u answered all of my questions.

you da stud man... @ me

 

Any news on a dyno date or is it still up in ther 100s?

 

All I have to say is you guys are crazy, obsessed *****

 

Any updates?

 

Unfornately, I'm not getting emailed updates to this thread. Sorry for the delay in the replys, but life sometimes gets in the way of the .org.

As for the dyno, I've driven well over 100 miles since the install. The manifold has definitely changed the A/F ratio, as I was perfectly tuned before, but am now running rich up high. This will create some questions in the dyno comparisons.

As for the dyno, I've contacted the shop that does my dyno stuff. They are awaiting a new air filter for the A/F meter. They should have it some time in the next week or so. Seeing how it is that I need to tune the A/F ratios, it's pointless to pay to dyno now when I won't have the A/F curves to tune by. Once they get the part in, I'll get on the schedule.

BTW... if you want to know what else is done with the car, etc, visit my web-site for a mod listing.

It's too hard to say how the mod will react on other cars with different mods. Only time will tell.

 

is this a direct replacement???

http://maxima.theowensfamily.com/intake.asp

With this it seems to be....i want to see the gains....I can bore it out myself so that's no problem....

 

I can't see any differences in your pictures. So far I don't think you got any gains from the new lower IM.

 

The IM is a direct replacement.

As for the differences, look at the last 2 pictures. The bump is located inside the IM runner, but next to where the fuel injector sits. It's a very very small bump (maybe < 2mm tall), but it's present in each and every port in the IM.

I'm still waiting on the dyno shop to get the air filters in to dyno.

 

Studman,
I love the pics and information. This is great stuff.

Give me a handfull of hours with my Makita die grinder and some cartridge rolls and I'll clean that thing up so the 2002 flows better than the 2004 without a problem. Honestly though, the finish inside those ports looks incredibly smooth. That's a great looking casting. It wouldn't take much with some 150 grit, followed by 240 grit to get those ports polished and gleaming.

Your thoughts about gasket matching that intake are on the money IF the openings in the heads match the gaskets exactly, which they don't appear to do. It doesn't look to me like there's any room to open them up.

If you open up the ports in the lower intake where they meet the heads, and you make them larger than the openings in the heads, you'll create a ridge that will cause turbulance kill airflow.

Based on the pics you've provided thus far, it looks like the stock intake and the heads are perfectly port matched from the factory. This is based on the marks I see from the O-ring gaskets around the ports in the heads, and the pics of the gaskets on the intake.

You should mock up the lower on the motor with the gaskets, and peer down inside the ports to see if you have any room for porting before you work them over.

 

BUMP!!!

Anything new - status on this?

 

Not yet. I was supposed to dyno today, but I didn't get back from South Florida (Miami / the Keys) in time to get the car ready for dynoing.

I'm rescheduling the dyno, but it looks busy for them, as there is a big American car show going on during the 4th of July weekend. I'll post up once I know more.

 

Any news? Dont mean to rush you or be rude just a bit excited to have a possible new power mod.

 

Not Dyno results? Do you have a past dyno before the lower manifold....

 

Ok. Sorry for the long delay in posting up. Recently, I threw a SES light (not uncommon for me) with a P0507. That basically says that the intake idle air volume is off. I realized that I had reset the ECU, but had not told it to learn the air volume. So today, I reset the ECU again, and then reprogrammed the idle air volume as well. I've driven 68 miles without the SES light, and no codes are stored or pending.

I am calling tomorrow to see if I can dyno this week sometime, or if it will be next week. Either way (unless there is a problem with the shop), I should know if there are any gains in the near future.

I'll keep you informed as I know more.

 

this is why he is the "studman"