R34 Stagea RB25DETNEO With FF plenum

Chris250 · Post by **Chris250** » Fri Aug 21, 2015 12:53 am

I have a customer who's fitted a Stagea RB25DET NEO engine into his 180SX, during the install a Freddy Front facing plenum was fitted.

The trouble with the manifold is it's designed for a normal RB25DET and required an R33 AAC and throttle position sensor, while the throttle position sensor is working perfectly it is idling at approx 2000RPM, if the air hose gets blocked off it idles nice and low but would like full functionality, is there any differences between the R34 & R33 idle control valves settings that should be adjusted?

STATUS · Post by **STATUS** » Wed Oct 28, 2015 11:33 am

Neo is really touchy we do dozens of them with nistune each month, it must have all factory fitted sensors and valves to run properly.. yes you can botch it but it becomes pretty average to live with as a daily driver. we have a few C34 stageas over 400awkw with nistune and all the factory gear with FFP but running perfectly. A plumb back bov is also a great help as the idle can become tiresome to setup without one due to reversion.

Matt · Post by **Matt** » Fri Oct 30, 2015 12:20 am

Hey Trent have you tried HPX or R35 MAF slot sensors in blow through configuration? It gets around the reversion issue we see all to often with suck through MAFs

STATUS · Post by **STATUS** » Thu Nov 26, 2015 3:59 pm

yeah the HPX ones are a pain in the ass and cause more issues especially the later ecus, the hpx in a 4inch pipe has such low resolution the ecu continually comes up with MAF errors (internal coding against expected maf v vs rpm maybe?) , if we drop it down to 3inch the errors go away but it hurts power so we generally fit them post cooler now.

S14a seems to be the most touchy regarding maf vs rpm errors... i thought it may be the supplier for the HPX but the last one i got from you guys did the same thing.

Bigger engines like 3litres etc its not an issue as the resolution is fine.

even with the Maf DTC flag removed they still false limit in a 4inch pipe... much like unplugging it.

Matt · Post by **Matt** » Thu Nov 26, 2015 11:43 pm

Interesting to read this here. I'm running HPX on both of my vehicles but this is in 3" configuration so probably why no issues (suck through). We also did testing with HPX in 3.5" and 4" tubing. btw we are using the HPX N-1 version (not the original HPX... I never got that one working properly)

Stabilitywise it starts to drop with the larger tube size, so we found that using an air straightener is essential. Anyone who buys a HPX-N1 I now include a copy of this document:
http://nistune.com/docs/Nistune%20MAF%2 ... 0Notes.pdf

So those HPX-N1 in the 4" pipe are they using an air straightener at all?

Which ECUs are showing the MAF errors with HPX? Normally these should not be showing less than 1 volt. If it drops under a volt you will get MAF DTC code and you will get the ECU using the default (limp value)

Post cooler is the way to go if you can find a good section of pipe, and there is no oil or condensation in the piping which will ruin the sensor

S14a seems to be the most touchy regarding maf vs rpm errors... i thought it may be the supplier for the HPX but the last one i got from you guys did the same thing.

I have S14A as my daily driver with just the normal T28 and 98/E85 but no issues. Please SMS me the voltage you are seeing and any details.

even with the Maf DTC flag removed they still false limit in a 4inch pipe... much like unplugging it.

Unflagging the DTC filter is not enough. You actually need to drop the MAF minimum voltage limit. It has been added for Z32 and R32 ECUs in Feature pack. It also is available in S14A as 'Low AFM voltage enrichment trigger' among most other SR20s. That should fix that problem!

If you have any questions when tuning, dont hesitate to call. That way if I know there is an issue, either I can provide you a solution (like now) or investigate what the cause is. First issues I've heard of undershoot in the HPX sensors

Matt · Post by **Matt** » Fri Nov 27, 2015 4:47 pm

Links for purchasing straighteners below. I may stock a few of the 3.5" and 4" ones. However make sure they are fastened securely!!

One of the guys here riveted his in and it got sucked through the turbo into the engine

STATUS · Post by **STATUS** » Wed Dec 02, 2015 9:38 pm

it only does it up at high rpm the low voltage i can work around. we have your test Air straightner here, i use it to demonstrate what is a good setup to those that dont use them.

soon as we swapped to 3" the DTC went away and never re-occurs, re instal 4" bingo false limits and instant AFM codes... very odd lol

STATUS · Post by **STATUS** » Wed Dec 02, 2015 9:47 pm

i had a quick look for the logs but as i do so many cars per week (15-25) i pretty much clear my log folder each night.... makes sifting through them quick and easy the next day.

especially nowadays as the trace function is pretty much all i use.

Matt · Post by **Matt** » Thu Dec 03, 2015 9:57 am

okay no probs. I tend to split each run into a different folder, but understood that most of the time you dont need to keep the logs.

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R34 Stagea RB25DETNEO With FF plenum

R34 Stagea RB25DETNEO With FF plenum

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