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Discussion Starter · #1 ·
Hi everyone,

I will swap the K20A2-intake tract (Euro PRA-Spec) of my Elise:
  • optimized CAI
  • adapted throttle body ID
  • manifold, supporting a higher volumetric efficiency
  • ITR cams
  • and a KPro tune
  • header and exhaust are already done

Yesterday I measured the maximum length between backplane-isolation surface and flange interphase of the cylinder head. Sadly there are only around 260 mm, which can be easy offerd for the 272 mm RRC manifold. For clearance (around 20 mm for braking rotation and so on) and the missing 12 mm there is a job to do.

Is there anyone who already done this?

Many thanks for your helpfully replay and discussion...

MingLotus
 

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Hi everyone,

I will swap the K20A2-intake tract (Euro PRA-Spec) of my Elise:
  • optimized CAI
  • adapted throttle body ID
  • manifold, supporting a higher volumetric efficiency
  • ITR cams
  • and a KPro tune
  • header and exhaust are already done

Yesterday I measured the maximum length between backplane-isolation surface and flange interphase of the cylinder head. Sadly there are only around 260 mm, which can be easy offerd for the 272 mm RRC manifold. For clearance (around 20 mm for braking rotation and so on) and the missing 12 mm there is a job to do.

Is there anyone who already done this?

Many thanks for your helpfully replay and discussion...

MingLotus
So you are asking if the RRC manifold on the k20A can fit in the Elise engine bay without hitting the firewall?


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What intake is on there now? (none - is it a new build?)
The PRC, PRB, RBC & RRC are all very close in size. BTW the RBC makes more power than the RRC.
Worst case you can move the firewall. I did, and it's not that hard. You cut it out & replace it with fiberglass or aluminum to eliminate the pocket behind the seats.
 

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Discussion Starter · #4 ·
So you are asking if the RRC manifold on the k20A can fit in the Elise engine bay without hitting the firewall?
Yes, that's I want to know...actually the Elise is runing (or doing it's hibernation :popcorn:) with a PRB manifold, which is around 250 mm (flange to plenum's to end)
 

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Discussion Starter · #5 · (Edited)
What intake is on there now? (none - is it a new build?)
It is a PRB from a UK Version of the K20A2.

Worst case you can move the firewall. I did, and it's not that hard. You cut it out & replace it with fiberglass or aluminum to eliminate the pocket behind the seats.
Thanks man, good information...so without cutting there is no way to fit in a RRC (or RBC).

BTW the RBC makes more power than the RRC.
Seems to be depended on the tuners passion ;). In my research to that topic I found both...finally both the RRC and RBC will gain engine power in the top end (about +5 lbft wtq) and cause some power drop (some -10 lbft wtq) drop around VTEC actuation compared to the stock PRB manifold (s. Richard Holdener, "Building Honda K-Series Engine Performance", CarTech, p. 31) or e.g. here

Thanks for your information...:up:
 

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Discussion Starter · #6 ·
Decision

With the upper information in mind I will stick on the PRB manifold (for now...there is some more unused space among the actual plenum...we will see what we can do :D) and match it's port to the bigger ID of the high flow throttle body and the higher flow loving intake. Calculation recommend something between 85 mm < ID > 70 mm, as the gradient of pressure drop over ID (dp/dID) began to flatten assuming 220 whp, which I am targeting.
 

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ive got a solid inch plus from my oem k20a2 intake manifold to my firewall. i was also told the oem wouldnt fit. i believe the rbc is on a few k swapped cars and fits, but id do some research and double check.
 

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Discussion Starter · #9 ·
Some additional information concerning the K20a manifold...

The K20Z4 (Euro type R, FN2) engine uses the RSP manifold, which seems to have some potential to reach a similar volumetric efficiency at high rpm compared to the RRC...at nearly the same length as the PRB or PRC has. For those thinking about this manifold for their K20A-Elise, there are some treatment to do:
  • water neck has to cut off
  • IAVC has to be shaped in
  • and some other optional things...
 

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Discussion Starter · #10 ·
The K20Z4 (Euro type R, FN2) engine uses the RSP manifold, which seems to have some potential to reach a similar volumetric efficiency at high rpm compared to the RRC...at nearly the same length as the PRB or PRC has. For those thinking about this manifold for their K20A-Elise, there are some treatment to do:
  • water neck has to cut off
  • IAVC has to be shaped in
  • and some other optional things...
Every year one information in addition :D:

  • RSP IM depth is 250 mm flange to farthest point of plenum
  • PRC IM depth is 228 mm
 
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