Jump to content
SAU Community

Potential MAP Reference Point

Radical_Goodspeed
 Share

Recommended Posts

Radical_Goodspeed Rookie

Radical_Goodspeed

Posted
Posted

So I'm in the final stages of assembling my single turbo RB30/26 and had a question regarding MAP reference points. 

I've seen several recommendations such as tapping the cylinder 2/3 ITB, tapping the intake manifold at cylinder 2/3, or using a point on IAC.

First two are doable but require permanently modify part and the third is "out" as I plan to delete the IAC. 

All that to say my question is can I used the "bleeder" in the center of the ballance tube as a MAP Reference?

I'm running a catch can so I don't need it for the PCV system. My thought process is it "pulls" from all 6 cylinder, and it's between the ITB and the cylinders making it ideal for MAP reference according to what I can find.

Thoughts?

Link to comment
https://www.sau.com.au/forums/topic/486200-potential-map-reference-point/
Share on other sites
GTSBoy Grand Master

GTSBoy

Posted
Posted

Getting a decent signal from all 6 throats is a challenge. I don't know for sure, but I suspect that the stock balance tube is not ideal for it.

I have done it on an ALFA 4 cylinder (about 35 years ago, so don't ask for too many details). We drilled 4x holes in the manifold runners, put in some fittings and ran hoses to a decent sized (I think it was about 20mm diameter) pipe that ran the length of the inlet manifold. So, it was quite a decent volume. There is a "tuning" balance to be found between the volume of the common plenum on such a thing and the diameter of the pipes running from it to the runners. You need the volume to be large enough to damp out the sharp spikes in pressure signal you get as each runner gets sucked on by its cylinder, but not so large that it becomes too slow to respond to actual changes in MAP. And you need the hoses to be small enough to transmit the signal quickly, but not so small that they delay the signal.

You might have to have more than one go at it, if there isn't any actual success based wisdom to be had here. Hopefully there is.

Anyway, I would not do it on only a couple of cylinders.

I would also not care about "permanently modifying a part". Just bloody drill holes and make stuff better. There is nothing sacred about any GTR unless it is a genuine museum piece that you shouldn't be modifying at all anyway.

joshuaho96 Veteran

joshuaho96

Posted
Posted
2 hours ago, Radical_Goodspeed said:

So I'm in the final stages of assembling my single turbo RB30/26 and had a question regarding MAP reference points. 

I've seen several recommendations such as tapping the cylinder 2/3 ITB, tapping the intake manifold at cylinder 2/3, or using a point on IAC.

First two are doable but require permanently modify part and the third is "out" as I plan to delete the IAC. 

All that to say my question is can I used the "bleeder" in the center of the ballance tube as a MAP Reference?

I'm running a catch can so I don't need it for the PCV system. My thought process is it "pulls" from all 6 cylinder, and it's between the ITB and the cylinders making it ideal for MAP reference according to what I can find.

Thoughts?

Isn't there a fitting on the back of the balance tube? That's what the OEM boost gauge uses.

GTSBoy Grand Master

GTSBoy

Posted
Posted
2 hours ago, joshuaho96 said:

That's what the OEM boost gauge uses.

That's just a gauge, with a certain amount of electronic damping, and no-one cares if it is timely-accurate. I'd hesitate to use it for an ECU MAP input without knowing that it was a nice signal. Responsive but smooth. Not laggy. Not lumpy.

joshuaho96 Veteran

joshuaho96

Posted
Posted
14 minutes ago, GTSBoy said:

That's just a gauge, with a certain amount of electronic damping, and no-one cares if it is timely-accurate. I'd hesitate to use it for an ECU MAP input without knowing that it was a nice signal. Responsive but smooth. Not laggy. Not lumpy.

AFAIK I've seen other people recommend using the back of the balance tube as well. Andre Simon from HPA at least. I can't imagine it being that far off from ideal even if it was only used to drive a boost gauge from the factory.

  • 2 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Leak from Tokico BM50 Brake Master Cylinder

      By GTSBoy · Posted

      HFM BM57 has a "bad" knee point, IIRC. It's not the same thing as the later R chassis MC.
    • Duncan
      Who has a Infiniti Q60, Q50 (V37)?

      By Duncan · Posted

      The ATTESSA is functionally identical to R34; there were a bunch of JDM models that continued ATTESSA including Fuga/Q70, Skyline/Q50, Cima etc as an option. All with Auto only and I think mostly for snow regions. AFAIK there were no AWD VR30DDTT sold in Australia - it is on my to do list to check regs for racing a LHD car in Targa/ATR/AASA/CAMS events because if I can get the auto to work it would be interesting to run a 4wd car The Ecuteck TCM tuning is the same model as their ECU tuning, they already have it for R35 and Dose's favourite, BMW. You buy "points" to allow your computer to be tuned, buy either a bluetooth (phone app) or bluetooth+USB+Key (phone and PC) dongle, and pay for a tune that will be locked to your tuner ( ). You can also access the tuning software yourself but 1. it is mega expensive and 2. these computers have a billion parameters that intersect, so how could you ever spend enough time on it to get a decent result.
    • MBS206
      Who has a Infiniti Q60, Q50 (V37)?

      By MBS206 · Posted

      Or, is it a case of what it is like owning an R series Skyline? NFI what the previous owner has done or fiddled with... Ha ha ha After reading through this thread, I went on a bit of a research about the Q50/Q60. Now I'm quite intrigued by them! Is the AWD in them more like a WRX where it's always AWD, or is it more like the ATTESSA in the GTRs? By the sound of this TCU tuning, this sounds like a case of someone has made some real software for it, and you just need the right piece of hardware, and then you license that specific vehicle/TCU. Or is this a case of the software will be really expensive so only a few tuners have it, and you still have to pay a license per vehicle?
    • CF.Panda
      R34 25GT Engine Light 21

      By CF.Panda · Posted

      By popular demand.. it was a coil. Got my hands on 1 new OEM coil, replaced with the one that made the less noise difference when I unplugged it while the car was running and started the car up. No stutter and the engine light was gone. I guess I’ll buy the other 5 they have lol
    • joshuaho96
      R34 25GT Engine Light 21

      By joshuaho96 · Posted

      No, code 21 is very straightforward. It can only be the things described in that diagnostic flow. In fact it has no way of knowing that the spark plug resistance is out of spec.
×
×
  • Create New...