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

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Old 03-26-04, 11:54 PM
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Question 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.

Old 03-27-04, 12:00 AM
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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
Old 03-27-04, 12:11 AM
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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.
Old 03-27-04, 12:16 AM
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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.
Old 03-27-04, 10:34 AM
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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.
Old 03-27-04, 09:20 PM
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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.

Old 03-28-04, 10:13 AM
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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.
Old 03-28-04, 09:15 PM
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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.
Old 03-28-04, 10:52 PM
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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!!
Old 03-29-04, 01:12 AM
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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
Old 03-29-04, 01:59 AM
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www.mazdaformance.com will be cheaper than the dealer by at least 25%
Old 04-09-07, 05:05 PM
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Bump from the dead...

Mazdaformance seems to not be around anymore. Anyplace out there cheaper than mazdatrix for these things?
Old 04-09-07, 07:37 PM
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Mazda dealer? They're an expensive item regardless, and I have no idea why.
Old 04-09-07, 08:09 PM
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http://www.mazdatrix.com/c-6.htm
Old 04-09-07, 09:01 PM
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Originally Posted by rotarychainsaw
Bump from the dead...

Mazdaformance seems to not be around anymore. Anyplace out there cheaper than mazdatrix for these things?
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.
Old 04-10-07, 08:11 AM
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Originally Posted by rotarychainsaw
Bump from the dead...

Mazdaformance seems to not be around anymore. Anyplace out there cheaper than mazdatrix for these things?
Could always sign up for www.mazdamotorsports.com

James
Old 04-10-07, 11:42 AM
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I wasn't planning on doing any racing though... and they want a SSN, sounds serious.
Old 04-10-07, 10:50 PM
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Originally Posted by rotarychainsaw
I wasn't planning on doing any racing though... and they want a SSN, sounds serious.
The discount is rather serious
Old 12-29-08, 02:52 AM
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Hello, sorry to bring this back from the dead. Is the RE primary injector diffuser the same as an FC or REW?

Thanks
~Tweak
Old 12-30-08, 02:29 AM
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Looks like I should be using the REW diffusers if anybody is searching and has found this thread.
Old 12-30-08, 03:00 AM
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cheers mate

Im on the look out for some secondary intake ones at the monent
didnt know ths thread even lived, good info
Old 12-30-08, 03:13 AM
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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 )

Last edited by TweakGames; 12-30-08 at 03:16 AM.
Old 12-30-08, 03:31 AM
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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)


By antman01
Old 12-30-08, 10:19 PM
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Originally Posted by Havoc
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)


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.
Old 12-31-08, 01:34 AM
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lol yeh only had there as a template. Is all good now
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