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13B-RE UIM on S5 13bt LIM? What is needed to make it work?(searched)

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Old Jul 27, 2007 | 11:21 AM
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13B-RE UIM on S5 13bt LIM? What is needed to make it work?(searched)

While my engine is apart I have been thinking of making some extra changes. I'd like to get a 13b-RE UIM and use in my setup but I couldn't find any info on what is needed to do this by searching. Does the RE UIM bolt up to the S5 turbo LIM or do I need an adapter or do some port matching? Also, can the S5 TB be used or do I have to use the RE TB?
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Old Jul 27, 2007 | 01:56 PM
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Originally Posted by Juiceh
While my engine is apart I have been thinking of making some extra changes. I'd like to get a 13b-RE UIM and use in my setup but I couldn't find any info on what is needed to do this by searching. Does the RE UIM bolt up to the S5 turbo LIM or do I need an adapter or do some port matching? Also, can the S5 TB be used or do I have to use the RE TB?
Don't bother. Putting an equal length runner UIM in place of an unequal length S5 upper introduces flow differences between the front and rear rotors, and next to zero gain in power.
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Old Jul 27, 2007 | 02:36 PM
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The S5 T2 UIM looks likes its equal length to me. The LIM on the other hand, looks like the front rotors runners are a little longer than the rear rotor runners.

The 13b-RE UIM is supposed to be better for higher boost and top end power, that is why I would like to do this. It also looks alot nicer than the s5 t2 UIM.
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Old Jul 27, 2007 | 03:40 PM
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actually...the S4 TII uim is equal length....

But the S5 - if you look closely - has a taller rear runner, meaning slightly longer. Took me a few times of off and on before I noticed.

I'd believe the RE UIM is better for top end from a purely visual based flow analysis (ie: looks more direct ) but, you're only getting 1/2 of the benefit being that its only 1/2 the manifold. I'd say a full RE setup (and engine) vs. a full FC setup would be a very measurable difference, but just the top...I dunno. It may turn out like REW upper in that you simply shift the pwoer band around a bit, might be worth a try.

As far as their relative dimensions to fit them to one another goes.......not sure, never had them side by side.
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Old Jul 27, 2007 | 03:52 PM
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I was planning on doing this also, but I can't find an adapter...
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Old Jul 27, 2007 | 04:04 PM
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Originally Posted by classicauto
It may turn out like REW upper in that you simply shift the pwoer band around a bit, might be worth a try.
Thats what I want to find out. I have an FD UIM, but I would prefer an RE UIM(visually) if they both offer similar benefits.
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Old Jul 27, 2007 | 04:13 PM
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Originally Posted by Juiceh
The S5 T2 UIM looks likes its equal length to me. The LIM on the other hand, looks like the front rotors runners are a little longer than the rear rotor runners.

The 13b-RE UIM is supposed to be better for higher boost and top end power, that is why I would like to do this. It also looks alot nicer than the s5 t2 UIM.
The S5 upper is definitely not equal length. The runners get progressively shorter as you move rear to front, just as the LIM runners get progressively longer.

Take a look at the attached picture: the height of the runners increases as you move left to right.

Build a flowbench and you can easily see the differences, or use a dual channel wideband to compare the AFR's before and after your swap, and you'll see what I mean.
Attached Thumbnails 13B-RE UIM on S5 13bt LIM? What is needed to make it work?(searched)-uim.jpg  
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Old Jul 27, 2007 | 04:25 PM
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Wow thanks for the pic. Never really noticed that.

However, people have had good results swapping an equal length FD UIM onto the S5 LIM. So, I think this will have similar gains. Unless the FD UIM is not equal length, and if thats the case I should really STFU.
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Old Jul 27, 2007 | 04:32 PM
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Originally Posted by Juiceh
Wow thanks for the pic. Never really noticed that.

However, people have had good results swapping an equal length FD UIM onto the S5 LIM. So, I think this will have similar gains. Unless the FD UIM is not equal length, and if thats the case I should really STFU.
I'm yet to see any worthwhile gains from doing the FD swap. Ever seen a dyno graph to back it up? Only reason people do this is for aesthetic purposes.

FD UIM is equal length... that's much of the problem: putting an equal length manifold in place of an unequal length manifold.
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Old Jul 27, 2007 | 04:40 PM
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Originally Posted by scathcart
I'm yet to see any worthwhile gains from doing the FD swap. Ever seen a dyno graph to back it up?
Only once.....
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/conclusive-b2b-dyno-tests-fd-uim-fc-uim-655708/

Note the lack of change in topend, just shifting of the powerband

Personally I think that any main benefit of either setup can only really be sought with the rest of the setup in place. Ie. a full RE manifold/engine vs. a full FC mani and engine or an REW etc....
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Old Jul 27, 2007 | 05:09 PM
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[QUOTE=classicauto;7178841]Only once.....
https://www.rx7club.com/showthread.php?t=655708

Note the lack of change in topend, just shifting of the powerband

Personally I think that any main benefit of either setup can only really be sought with the rest of the setup in place. Ie. a full RE manifold/engine vs. a full FC mani and engine or an REW etc....[/QUOTE

I remember that thread, but I also remembered that he had stated the AFR's being richer with the FC manifold, which would certainly make up for the couple of horsepower. The slight shift in powerband seems to be the only difference.

I definitely agree on the benefit arriving from the different engines. The larger runners, when properly ported and matched to a turbo, definitely change the power produced.
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Old Jul 27, 2007 | 08:56 PM
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According to those dyno sheets, there is a HUGE increase in midrange torque.

If you have enough money anything can be done, I'll make you a one off adapter but its going to be an arm and a leg
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Old Jul 29, 2007 | 12:53 PM
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Does anyone know if the 13bt throttle body will bolt up to the 13b-RE UIM?
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Old Jul 29, 2007 | 02:31 PM
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No, it won't.
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