realBlackSunshine

iTrader: (1)

Is there no such thing as a replacement intake manifold for the RX-8?? I find it hard to believe this POS plastic oem version is the best anybody can do. After my engine replacement at 70k I've been having issues with vacum leaks and air to fuel ratios.....dealership seems to believe it is due to worn grumets on intake manifold. I think it has more to do with the manifold is junk! there has to be a better one on the market somewhere, but I can't seem to find it...........any help would be appreciated

Highway8

iTrader: (11)

The plastic upper intake manifold is really a pretty good piece for na and FI up to Atleast 350 rwhp. There are no current aftermarket UIM on the market but turblown is working on one.Vacuum leaks? That would be an easy check. Spray some water or carb cleaner until you find the leak. Not sure what grommets they would be referring too. There isn't much to leak or wear out. Honestly I would bet they crossed something or you have a different problem. BTW, what kind of afr problems are you having and how was that diagnosed? If you want to replace the UIM, you could buy a used oem UIM for pretty cheap.

Beodude

iTrader: (3)

The stock intake mani is actually pretty good. Mazda did a lot of work on the engine, getting all the lengths of runners and diameters just right. The time it would take to make one that would be better would be ridiculous. If somebody did make one, it would probably be super expensive due to development time.

nycgps

iTrader: (1)

stock intake UIM is junk? ok, that simply means you have ZERO idea how this system works. You should keep those comments to yourself cuz it just made u look like a moron.

9krpmrx8

iTrader: (46)

+1, I agree with NYCGPS, you have no clue what you are talking about.

kma5783

iTrader: (7)

The UIM does have seals, kind of like O-Rings on all the mating surfaces(In between the Throttle body, LIM, and if you have a 6 port in between the lower extension part of the UIM) and could be a source of a leak, not very likely though.

Like Highway8 said take some carb cleaner and spray it around your engine when your idle jumps you've found your leak.

Do you have an aftermarket intake? Is the VFAD removed? If so did you cap the VFAD nipple behind the throttle body on the UIM?

nycgps

iTrader: (1)

T_T

me ? ...

nycgps

iTrader: (1)

forgot to add, you wonder why you can't find a "replacement" manifold? cuz the stock is so good that there is almost no point to make another one.

You could design another manifold but that also means you have to redesign the whole system, cuz the intake manifold is part of the puzzle, you change one part, you just gotta redesign everything else. and I doubt anybody can make another system that works so well at such wide RPM range.

There is ONE out there but they made it because they need it to fit their SC system to the car, NOT because the stock manifold is junk.

ok, move on. do some research b4 u spill ur next bs.

9krpmrx8

iTrader: (46)

No, I meant I agree.

Wingznut

iTrader: (1)

Be very careful when spraying flammable liquids (i.e. carb cleaner) around your engine. I have seen more than a few people start a fire by getting it on the exhaust manifold.

That being said, the above posters are right that it's an excellent tool for finding vacuum leaks. Just don't go crazy with it.

8 Maniac

iTrader: (1)

I'm curious why you're convinced the manifold is crap. Because it's plastic? The actual design of it? Unless you can point to design or material flaws that can be shown to cause problems, it's kind of silly to call it crap.