Rb25 Neo Tuning Question.

[Lopin18]

Im trying to understand this engine, i really dont want to test how far the timing goes, since the fuel here isnt that safe.... not trustworthy.

So. i got 360hp/310tq @ 18 psi on a Holset HE341 turbo. VTC Disabled. Running on 100 octane fuel. stock engine with a greddy copy intake.

I understand that this Neo rb25, comes with stronger head parts. solid lifters etc....

2 simple questions:

- How safe is it to race this engine up to 8k RPMs, ill be drifting it. So far im running 7600 rpms. Not a hitch on my last event. Running Castrol full synthetic 10-50w

- Timing map, 5000-6000 rpms high load im seeing 27-25 ignition timing, on the 6000+ range high load im seeing 23-19 timing. How are those numbers for an engine like this one? Are they low, high? What timing numbers are you guys seeing on ur setups with 98+ octane fuel and how much hp/tq,

Edit: Interesting, seems that the Stagea RB25 Neo, the first mark on the crank pulley is the TDC 0 Mark, ill have to do the timing again.

Im interested to know so i can have an idea of how this engine behaves and what timing numbers are low/safe/high for it.

On the last tune/dyno runs, we used headphones with knock sensors, we heard no noise at all other than injectors and normal noise, no knocking at all.

Thanks in advance.

Edited July 4, 2014 by Lopin18

[GTSBoy]

I wouldn't run a 25 Neo to 8k regularly, especially in a thrashy fashion (like drift tends to be). They seem happy enough in the mid 7s. You really really really DO NOT WANT to be banging the limiter though. So out of the 2 choices of banging the limiter or setting it high enough that you don't bang it, then setting it high and revving the engine a bit too much is probably the less evil choice. On that basis, if that's your plan, then you really should consider some stronger valve springs. The Neos are shim over bucket. At the first sign of valve float they will be prone to spitting shims, and you don't want that.

The only other useful thing I have to say is, find a way to get VCT running. You want that to be working.

Less useful stuff I have to say....The stock maps have 20 - 25 degrees in the 5000-6000 range at highish loads before they drop right off to single digits at the highest mapped loads (which is part of the R&R strategy). Above 6000 at the same loads it's more consistently around 23-24 degrees. Your loads at 18psi on a bigger turbo will be much higher than these loads though. I would suspect that you running 27 degrees in that range might be a little on the high side. A lot of other timing numbers you hear from RB25 tunes are below 20 degrees at significant load. Maybe at the higher revs you're talking about here they would creep back up above 20 degrees, but I would be surprised to see a lot of them get as high as you have.

So the obvious knock detection questions need to be answered (or considered where you already have the answers).

• Did not hear any knock = probably isn't knocking.
• If you did not do extensive sensitivity testing = don't really know if it starts knocking at just a little more timing, or if you never hear knocking even though it must eventually knock.
• If you play with the timing you can find the point where adding timing doesn't gain you more torque and that lets you know when to stop anyway, even if you don't hear knock.

Because you're ROM tuning, I don't know how much time you spent in the last 2 points. If you've done enough to convince yourself that you're OK, then all's good. If not then perhaps back to the dyno to find out. Using the emulator at least means you can tune live though, so you should be able to do everything that every other tuner would do, rather than the burn, test, edit, burn, test, edit, burn cycle that used to be the norm!

[Dose Pipe Sutututu]

Hey there.. just reading your post..

Listen to GTSBoy's advice, also coming from some backyard tuning experience you've got way too much timing at those boost levels. I won't tell you exactly how to do it or not however some advice.

• Less timing at mid range area
• A little more timing towards the top, i.e. more than the mid range
• RB's don't like a massive ramp in timing like other cars - unless it's on ethanol
• at 1.3bar on 98RON at peak torque, i.e. ~ max VE anything in the 20s is way too much timing (from my tuning experience) - shops/professionals might say other wise
  • however on that note, you've got VCT disabled so the motor will take a few more degrees of timing
  • I usually pop a couple of degrees in after VCT is disabled around 5000rpm (that's my personal preference)

[Lopin18]

Thanks, now i can sort of get an idea of how the RB likes timing.

A friend had a Neo too, revving it up to 8k for several years, not a problem ever, but im not in the same range of income as him soo i probably wont go up so far, maybe ill add so i can stay of the limiter more.

On the other hand, i set base timing to 15 on the second mark of the pulley (if i remember correctly) so that would mean im running 20 which makes things more aggresive.

Im not tuning it myself, i have a well backgrounded tuner doing the work. Im just learning about the RB to have an idea of how close or far we are from safety.

Ill be enabling the VTC soon and going back on the dyno, surely ill set the timing to 15 base and retest on the dyno everything. Amazingly we didnt see any knock and when we added some degrees on the high rpm/load section of the map, we saw torque improvement, so i think we are safe as far as audio from the knock headphones and tq band goes.

I will try to get the map up here for you guys to see after i check the base timing to confirm it. Maybe ill do a run on the street and bring the map with the trail from the run.

For knock detection im using a SR20 Knock sensor, bolted to the block close to the stock knock sensors, with headphones and amplifier connected, i can hear everything, most of the time the injectors, but neither i or the tuner heard anything at any range other than the injectors. So i think we are safe in that part.

Edited July 4, 2014 by Lopin18

[Badgaz]

You need to filter out all the other noise with a high pass filter 6.5khz I believe.... Are you using a home brew knock detection amp?