Injector diffuser -- trash it or replace it? (13b RE)
 

Working on my Cosmo motor today and pulled this injector diffuser thingy out of my secondary injector bosses (in the LIM).

I'm thinking they don't look like much so I'm assuming to just toss em in the trash -- especially since one of them is broken already.

But do you think they do anything important enough to keep? I'll be replacing the injectors w/ 1600s anyways, but really can't imagine that it does much. I've posted a pic below. Hard to see in the pic, but the bottom of the injector fits into the top off the "diffuser" then the bottom of the diffuser has a few holes in it.

https://www.rx7club.com/attachment.p...postid=2835234

I would say that they are needed. And they are pricey. Your best bet is to use mazdaformance.com if you want to replace them.

Or join up with mazda competition.

James

Really? hmm, just can't see that they'd do much, but I dunno...

btw, in case I wasn't clear, the "diffuser" that I'm talking about is the long 3 legged thing on the bottom right of that pic. :)

Currently im not running the diffusers in my primary injectors because i lost them when i was doing a rebuild. :(

I wondered the same thing about them ... im sure they help with the atomization of the fuel, but it sure does look like it blocks alot of fuel. Ive driven without them for 1000 miles so far and have seen no ill effects.

The diffusers help atomize the fuel. There's an air hose that leads to a nipple in front of the throttle body...Fresh air is forced into the diffuser when the engine is under vacuum, and sprays out through the holes in the side of the diffuser. This further atomizes the fuel, resulting in a smoother running engine, better fuel economy and snappier throttle response...

I too have broken a few on removal...They're not cheap, at around $20, but I wouldn't build an engine without them....Also, they provide the seat and sealing surface for the injector lower o-ring.

Aaron, I think I see what you're talking about on my S5 N/A motor. There is a nipple below each of the secondary injectors -- right about where the diffusers would be. However, on my RE motor, there are 2 "bosses", but no nipples...

I've circled them in red in pic below. Sooooo, having said that, do you suppose w/o the extra vacuum that it'd still be as important. I'm almost wondering if I go ahead and just put the tops of the diffusers back in (since one is broken anyway) -- just to serve as the bottom seal. But aside from that, I just don't think they're going to do much... I could be totally wrong.

https://www.rx7club.com/attachment.p...postid=2837743

Forgot that you have an RE...In this case, I would simply assume that the bottom piece serves to atomize fuel simply because of impact. Personally, I would replace it. Mazda put some thought into these things. :)

Yep, the air feed and the plates both improve fuel atomisation, but nether requires the other to work. Just because there's no air feed doesn't mean the plates won't do the same thing on their own. Anything that improves atomisation is a good thing, and there are no downsides to having them, other than the cost of replacing broken ones of course. ;)

cool... I suppose that I should replace them then...

I suppose this is a dealership item? (doubtful if Autozone is going to have these puppies) Any idea what the 'official' name is? I mean if I call the dealership, they're going to be like "HUH?" :)

part numbers would be great if you have them, otherwise I'll just make some phone calls.
Thanks!!

last time i called the dealership asking for them, the parts guy had no idea what i was talking about, i even gave him everything right out of the FSM... except the part #. I hate dealerships, they dont know anything about rx7's. Even with their books :-O

www.mazdaformance.com will be cheaper than the dealer by at least 25%

Bump from the dead...

Mazdaformance seems to not be around anymore. Anyplace out there cheaper than mazdatrix for these things?

Mazda dealer? They're an expensive item regardless, and I have no idea why. :)

Lol, they're so expensive because they are necessary to make the car run right! Dern Mazda, I think a dealer might actually be cheaper than mazdatrix.

Could always sign up for www.mazdamotorsports.com

James

I wasn't planning on doing any racing though... and they want a SSN, sounds serious.

The discount is rather serious:)

Hello, sorry to bring this back from the dead. Is the RE primary injector diffuser the same as an FC or REW?

Thanks
~Tweak

Looks like I should be using the REW diffusers if anybody is searching and has found this thread. :D

cheers mate :D

Im on the look out for some secondary intake ones at the monent :D
didnt know ths thread even lived, good info

Havoc do you have your stock primary ones in yours by chance? Would be nice to have a confirmation on what exactly is in there (the FC or REW kind) I THOUGHT I had a 2 piece diffuser setup when I first took mine out, but I could be mistaken and I would really like to get it right. :)

Thanks
~Tweak

(so little info on the RE :( )

Hmm good question. I have the stock ones in.

I cant be 100% sure, but I think they are a one piece.
Also the diffuser is tapered on the primary ones I believe.

If I have to take them out again at some stage I will have a look (im only just putting it all back together now)

http://img122.imageshack.us/img122/5...9398557dk2.jpg
By antman01

Just an FYI here... but it would appear as though you have your LIM gasget on backwards. Ya might want to turn that around.

lol yeh only had there as a template. Is all good now