Road Warrior

iTrader: (16)

the post is long but informative

first off, the gaskets are of great quality and i purchased mine from nippon power. right off the get you will notice how thick these gaskets are and they are machined with great precision.

the install is pretty straight forward as you remove the upper and lower plenum. then you unbolt the manifold....i was able to do this without removing the fuel rails but its a bit tricky getting to the bolts. i didn't want mess up anything by removing the rails and it also saves time. BEFORE you install the gaskets please see the warning below!

as far as power i don't notice anything. the main reason i purchased the gaskets was to reduce the heat of the upper plenum and in return hope to reduce the air intake temps. i am very satisfied with the results of the reduction in heat although i do not have any proof other than touching the plenum after the engine has been running. there is a big difference between the before and after the installation of the gaskets. specifically, you can't even touch the plenum with the stock gaskets because it gets extremely hot, but after the next gear gaskets were installed you can rest your hand comfortably on the plenum and its only warm to the touch.



WARNING: PLEASE READ

you MUST take the thickness of these gaskets into consideration before buying or installing them because they add a lot of thickness and therefore more height to your upper plenum.

this was especially critical in my case. unfortunately i didn't know this until after i installed the gaskets and it took a lot of extra time to come up with a fix.

****if you have the crawford cast plenum***** beware, the plenum WILL hit your hood after the installation of the next gear gaskets. you can see the hood bulging (when closed) in the area where the plenum and hood are touching. there are three areas in particular that hit because you can see the paint scuffs on the plenum.

but don't worry there is hope!

i cut out the areas of the hood supports that were hitting the plenum. i didn't take out a lot of material because i didn't want to affect the structural integrity of the hood any more than necessary.

i used a 90 degree dremel and some cutting wheels (about 3 thin ones) and placed a piece of metal behind the support so i didn't penetrate the hood underneath. the material is thin and made of aluminum so cutting it is pretty easy. i used masking tape as my line for the cut.

i then deburred the areas where i cut and didn't leave any sharp edges where cracks can start. if you want to cut into a corner....drill a hole where your 90 is going to be and that will leave a nice rounded corner....this will also prevent cracking.

i then used some high temp gasket silicone for rubber bumpers to reduce vibration....you will notice these bumpers spread about underneath the supports after you remove the metal. they look like a round ball and appear to be silicone so thats what i used. it appears this is what adhears the supports to the hood in the middle area. so, if you don't replace these you may get some vibration in those areas where you have removed material from the support.

i then used some black spray paint to cover the unpainted area where you have removed part of the hood supports. this works pretty well as you can't even tell anything was done.

i am not sure how these gaskets would affect your plenum if your running any of the plenum spacers or the kinetix intake manifold. there are thinner gaskets on ebay but imo they are junk compared to the next gear.

if anyone is interested i can take some pics later....otherwise i won't bother as i am pretty much worn out from the stress and the install of the gasket adventure. its time to have a bevy

rw....out

Vash350Z

iTrader: (9)

do these install in place of the oem gaskets, or with them?

Road Warrior

iTrader: (16)

they replace the oem gaskets...they are an exact copy of the oem....very good quality

DavesZ#3

iTrader: (26)

Thanks Road Warrior, you've basically answered a question I been trying to get NextGear to answer for over a week now. I'm going to get a plenum spacer and thought about getting these thermal gaskets. It figured from the picture that they were fairly thick and might raise the height of the plenum enough to effect the clearance with the strutbar.

Exactly how thick do you estimate the gaskets are? How thick was the stock gasket?

Did you install all three or just the one between the manifold and plenum?

I assume all three are the same thickness, yes?

Thanks for the review, great info.

Road Warrior

iTrader: (16)

i installed all three...you can install the two lower, or the one upper if you are limited on space. even though, i cannot guarentee you will still have a clearance issue installing just the one upper or the two lower gaskets.

the thickness is roughly about 3/16" for each next gear gasket....so if you do all three your looking at 3/8" more height. the stock gaskets are about 1/4 the size of the next gear gaskets if not smaller. you should call next gear and have them measure for the exact size and then plan accordingly.

if you get a spacer you might have a clearance problem with your strut bar....and you can only raise that so high before your hitting the hood.

if you do the cutting on the hood supports you won't have a clearance problem with the crawford. i have been thinking of replacing my hood anyways with a carbon fiber one so i didn't really mind doing the cutting. it was an easy decision for me because of that reason.

for someone who installs the gaskets and finds out afterwards they have a clearance problem, the only alternative would be to take them back out, replace the hood with a cf if that gives more room, modify the oem hood, or get a crawford or stillen strut bar which is relocated in the front.

bottom line here is to check out your clearance tolerances before purchasing the gaskets, and more importantly if you already have the gaskets make sure you won't have a clearance problem before you do the install. after installing the gaskets don't slam down the hood....close it gently so you don't end up with a dent. i'm lucky i didn't dent my hood because i didn't even think about it at the time until i noticed my hood bulging out.

hope this helps out

Road Warrior

iTrader: (16)

there is also another company called fisherspeed that makes thermal gaskets for the z....never could get a hold of them though....sent several emails (only way to contact them) and its been over a month and no reply.

don't buy the ebay gaskets...they are thinner but they are not even close to the quality of the next gear gaskets...and they are only the two lower gaskets

DavesZ#3

iTrader: (26)

I've been trying to get in touch with NextGear with no luck for the past week.

Your right about Fisherspeed. Fisherspeed is just as bad if not worse. I suspect he's out of business since I'm getting no mail response and he has no phone number listing. His mailing address appears to be nothing more than a dropbox.

BTW, are there any stampings or markings on the gaskets that might indicate what they're made of. If it comes down to it, I might be tempted to locate some raw material myself and copy the stock gasket.

Road Warrior

iTrader: (16)

no indication of the material used....some kind of teflon i would think....and of course would have to be high temp and cut out exactly like the stock.

i talked to the folks at next gear....their gaskets are cut by a waterjet for perfect precision and an exact cut. maybe you could call next gear or nippon power and have them special order a thinner set of gaskets.

would be nice if they offered different sizes...but they are focused on the stock plenum z's it seems

ZU L8R

iTrader: (84)

I'm running these as well, I didn't run into any problems with the hood with my SSV manifold just in case anyone was thinking of that combo. As far as performance they do keep the manifold a lot cooler.

Z PHAT Z

iTrader: (46)

Even with a CF hood. I still got rubbing problem with the Crawford plenum. I did what you did, dremel out the part where it rubs.

DavesZ#3

iTrader: (26)

I finally heard back from somebody at NextGear. The gaskets are 1/8" thick for anybody else who's concerned about the clearance issues.

They've had several requests about just buying the single gasket instead of the set of three. He's supposed to let me know what the decide to do about it.

ZU L8R

iTrader: (84)

They told me they would do the single gasket for $59.95, I just went ahead and bought all 3.

Road Warrior

iTrader: (16)

the upper gasket is definately the easier of the set to install. i couldn't say which would be more beneficial the lowers or the upper. thats cool they will sell them individually...next gear seems like a good company and easy to talk with from my experience

laterz

DavesZ#3

iTrader: (26)

Zu L8r,

did you get yours directly from NextGear or did your come from Nippon Power?

Road Warrior

iTrader: (16)

pic of the hood modification that i made for clearance of the plenum

Phatmitzu

iTrader: (34)

There are 2 gaskets for the lower plenum? Stacked together? Can we only use one?

Road Warrior

iTrader: (16)

on the intake manifold there is a left and a right side gasket so you must use both. otherwise, you can use the one upper gasket that goes between the intake manifold and the plenum. as i mentioned before, the upper gasket would be the easier of the set to install but i am not sure which is more effective in reducing the temperature.

eventually, i would like to see a tb gasket as well and i hear nippon power is currently in the process of working on one. they are trying different sizes to optimize the effect by making sure the thickness is right.

Phatmitzu

iTrader: (34)

IC. Thanks.

DavesZ#3

iTrader: (26)

From what I remember reading on the Fisherspeed site, he went with just the upper gasket between the manifold and the plenum. That's where the most effect was seen. The gaskets between the block and manifold didn't have nearly as much effect. For the sake of simplicity, he went with the single gasket. I believe he also provided the TB gasket and he also offered a heater bypass to stop the flow of hot water from the block thru the TB. That's another little mod that I'm thinking about. The G35 Driver site has a writeup on it but the pictures don't really show much. All you need is a pice of tubing to bypass the TB and route the water directly back to the return.

vfr350

Just use a barbed straight thru hose coupler as the bypass, It works fine.....