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Compression Elbows: GReddy vs FEED

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Old 04-01-17, 06:52 PM
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Compression Elbows: GReddy vs FEED

Hello All,

So I have seen many posts in which people are asking if there is any value in spending ~$400 on the FEED elbow vs ~$100 on the GReddy one, but never an actual comparison, so here goes!


I purchased both and from what I see, other than having a brand preference, there are two major benefits to the FEED elbow:

1) The FEED elbow is 2 5/8" internal diameter at the entry vs the GReddy at 2 1/2".

2) The FEED elbow bulges to a much larger internal diameter and has a much smoother curve. In addition the way the elbow is shaped will produce a much better flow into the throttlebody, see pictures below (FEED is on the "top" or "right" of the photos).


In my opinion the FEED elbow is superior to the GReddy one. However, I think the $300 price difference is better spent elsewhere.

So unless you are a FEED obsessive I believe that this part will only be worthwhile to the few people who are really pushing their setup hard.

Thanks for reading, any questions welcome.

Tom





Last edited by TomSmy; 04-01-17 at 07:03 PM.
Old 04-01-17, 09:05 PM
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Looks like the FEED has a tube cast in for the AWS system, which might be nice for those trying to keep it somehow.

The difference in ID at the entry might be from the "step" in the Greddy design to work with couplers and the rest of their pipe kit.

Tough to armchair the air flow analysis, but the more gradual inner curve of Greddy might help with air flow to the front throttle blade.

Looks nice, though. The FEED one definitely stands out from the crowd.
Old 04-01-17, 09:48 PM
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Originally Posted by Narfle
The difference in ID at the entry might be from the "step" in the Greddy design to work with couplers and the rest of their pipe kit.
Yep that's exactly the reason for the ID difference at the entry, if you cut the step off the GReddy one it would match the FEED elbow.

Hopefully it shows in the pictures (is very obvious in person) - the big difference between the two for flow, is that the inside of the FEED curved section is way wider, the "bottom" is much lower and kind of bulges down.

Both are great items and the GReddy really is awesome value for the price point.

Last edited by TomSmy; 04-01-17 at 09:51 PM.
Old 04-02-17, 08:30 AM
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A side note question. How would the FEED play with the other GReddy hard intake tubes?
Old 04-02-17, 08:33 AM
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Originally Posted by Sgtblue
A side note question. How would the FEED play with the other GReddy hard intake tubes?
It won't mate up, or at least not and look pleasing at the connection. The angle on the FEED piece is quite a bit different from Greddy.
Old 04-02-17, 10:22 AM
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I don't know if this would make THAT big of a difference power-wise. I think a lot of it is aesthetic.

Probably a few horsepower on the top end IMHO. I think the real value is having the cool, rare part and it looks cooler .

Dale
Old 04-03-17, 09:17 AM
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Nice comparaison Tom!
I was always wondering if there was a difference.

I agree with those Gentlemen's.

I feel like that's one of parts that never got "changed" in 20years of technology and wayyy oversell due to its unbeatable price.
I mean 99% of the time buddy pop his hood it's a Greedy elbow

There was also the HKS version.
Compression Elbows: GReddy vs FEED-photo603.jpg
Compression Elbows: GReddy vs FEED-photo669.jpg

I also found this , but it might of simply got cut
Compression Elbows: GReddy vs FEED-photo874.jpg

Anyways
The Rotary-works is nice because it's 3"
BUT it's shitty that it need some cutting to fit.

I mean , no one ever taught of having a 3" Elbow
That's fits directly , no cutting ?
Old 04-03-17, 09:42 AM
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My stillway elbow looks exactly like the FEED one...
Attached Thumbnails Compression Elbows: GReddy vs FEED-img_7539.jpg  
Old 04-03-17, 08:16 PM
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Originally Posted by Spalato
My stillway elbow looks exactly like the FEED one...
i think it is the same casting. ive got one that is the same but blank where the logo would be
Old 04-05-17, 10:55 AM
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Other than GReddy, FEED, Stillway, and a few other elbows, LEG Motor Sport makes a CF elbow attached with the pipings. Retail like 125,000 yen or something, if I am correct. There are lines on the piece for you to cut and trim, if needed.




Old 04-05-17, 12:28 PM
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Oh damn.
Old 04-05-17, 12:38 PM
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That's a cool piece, but I think for $1200 I'd have the stock plastic elbow hydro-dipped.
Old 04-05-17, 01:43 PM
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Yeah, this CF piece elbow is really expensive, and one of a kind.

??????????? ?RX7? - LEG MOTOR SPORT???????

The website stated approx a 10hp gain though,
Old 04-05-17, 01:50 PM
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Originally Posted by Ka Kui
...The website stated approx a 10hp gain though,
Old 04-05-17, 03:20 PM
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I wonder what the weight difference is between the stock one and the CF one...$1200 to save a few grams of weight...seems legit

Lol

But still...its very very cool!
Old 04-05-17, 03:39 PM
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Have there been comparison studies done with these aftermarket elbows and OEM?
I haven't searched yet, but was wondering.

Quick results: but looking for others
https://www.rx7club.com/single-turbo...lastic-420777/

Last edited by MK3Brent; 04-05-17 at 03:42 PM.
Old 04-05-17, 03:52 PM
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Originally Posted by Spalato
I wonder what the weight difference is between the stock one and the CF one...$1200 to save a few grams of weight...seems legit

Lol

But still...its very very cool!
Originally Posted by LegSports
Weight is also -500 g from STD Our trial production Aluminum is -800 g, lightening to almost half!
500grams less than stock, apparently.
Old 04-05-17, 04:00 PM
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Maybe like the Australian SP version CF Intake box and pipings, this LEG Motor Sport CF piping and elbow maybe can keep the IC temperature slightly lower than aluminum pipings and elbow?
Old 04-05-17, 05:49 PM
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The stock piece is plastic, so little heat transfer there to combat.
But, as compared to metal aftermarket piping, it will heat-soak less and help AITs stay lower.
Old 04-12-17, 01:05 PM
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Originally Posted by Narfle
The stock piece is plastic, so little heat transfer there to combat.
But, as compared to metal aftermarket piping, it will heat-soak less and help AITs stay lower.
Perhaps, but remember this: heat transfer works both ways. For the same reason that aluminum will heat up quickly, it will also cool down quickly. Meaning, at WOT, the aluminum would very quickly want to get to the temperature of the air flowing through it. Heat soak is certainly a real thing, but I feel that sometimes we get caught up in it and think it will make a dramatic difference, when in actuality it won't.

If you're at the track running lap after lap, or you're sitting in stop and go traffic for an extended period, you will have heat soak, no matter what materials you're using. The added cost to prevent heat soak in a two or three foot section of intercooler piping, isn't merited.

Having said all that, the carbon fiber looks really cool, save for the fact it's the only carbon piece in the system. If you had all carbon fiber for all the piping and maybe the UIM, it'd look sick. But, the one piece just looks out of place to me.

Nick
Old 04-12-17, 01:22 PM
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Originally Posted by Brilliant7-LFC
...For the same reason that aluminum will heat up quickly, it will also cool down quickly. Meaning, at WOT, the aluminum would very quickly want to get to the temperature of the air flowing through it...
But wouldn't that mean its just continually soaking up the radiated engine bay heat and dumping it to the intake air?
Old 04-12-17, 08:04 PM
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Originally Posted by Sgtblue
But wouldn't that mean its just continually soaking up the radiated engine bay heat and dumping it to the intake air?
My overall point was that the cost/benefit of a carbon fiber charge pipe/compression elbow isn't really strong enough.

To answer your question though, yes the engine bay heat will radiate into the intake and have an effect on the AIT's. But, again because it heats up quickly, it also cools down quickly. So, as long as you have an efficient intercooler that's cooling that charge well enough, the aluminum piping will cool relatively quickly and thus the effect of the heat soak will
be lessened.

Having said all that, a little methanol injection would cure all of this and make whatever material you chose almost irrelevant.

Nick
Old 04-13-17, 05:34 AM
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These elbows we were discussing are located after the intercooler.
Old 04-13-17, 05:59 AM
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Precisely!

Thus, the charge will be cooler than the piping and what I'm saying holds water.

Nick
Old 05-03-17, 12:45 AM
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Side by side of a greddy knock off n a hks





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