Location of intake air temperature sensor

[Eidson, Mark]

This is more what I would have expected to find, thanks, me.
-----Original Message-----
From: green [mailto:green at nlenx.com]
Sent: Friday, May 28, 1999 12:33 PM
To: diy_efi at efi332.eng.ohio-state.edu
Subject: Re: Location of intake air temperature sensor



The SyTy system uses a MAT (manifold air temp) sensor.
This is in the manifold itself, after the turbo.  I'd think this is a
good/bad thing.  Bad, because it might be subject to heat soak of the
manifold itself, but good because it is actually measuring the air going
into the engine for fueling/timing calculations.  So it would take into
account turbo and intercooler efficiencies partially, as more/less fuel
would be delivered, and more/less timing would be employed, versus the air
temps.  If the sensor was before the turbo, it might measure ambient only,
while the air temps at the manifold would be much hotter, and vary a lot
(i've seen them rise 50-100 degrees in a 1/4 run in a syty).

It's interesting that the syty chip doesn't change fueling much versus the
MAT temp.....
here's the MAT temp fueling term table from the syty chips

0x04D1  F31M_TBLE   Base Pulse Inverse Air Temp vs ADMAT (ACSP Senso
Deg. K
        |  Hot   136   107   91.0  80.0  71.0  63.0  56.0  49.3  43.3  37.0
30.5  23.5  15.5  6.0   -8.5  Cold
----------------------------------------------------------------------------
-----------------------------------
(Deg. K)|  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B  0x9B
0x9B  0x9B  0x9D  0x9F  0xA5  0xC0

I'd think there'd be a direct relationship here between temperature and
fueling needs.

There's also a nifty table that is timing vs MAT and vs boost

0x02D2  F3_TABLE    Spark Advance Adjustment vs ADMAT1K
Deg. vs Deg. C & kPa Boost
        |  Cold  23.5  49.3  80.0  Hot
---------------------------------------
0.0     | 20.04 20.04 20.04 20.04 20.04
12.5    | 20.04 20.04 20.04 20.04 20.04
25.0    | 20.04 20.04 20.04 20.04 20.04
37.5    | 20.04 20.04 20.04 20.04 20.04
50.0    | 20.04 20.04 20.04 20.04 20.04
62.5    | 20.04 20.04 20.04 20.04 20.04
75.0    | 20.04 20.04 18.98 16.87 20.04
87.5    | 20.04 20.04 17.93 15.82 20.04
100.0   | 16.87 16.87 16.87 14.77 14.77


Sorry if that looks goofy in the email....
Brian Green
Syclone 160




|How does a MAP system compensate for the increased/reduced air temperature
|resulting from the turbo and intercooler?  me
|
|-----Original Message-----
|From: David A. Cooley [mailto:n5xmt at bellsouth.net]
|Sent: Friday, May 28, 1999 10:02 AM
|To: diy_efi at efi332.eng.ohio-state.edu
|Subject: Re: Location of intake air temperature sensor
|
|
|At 09:50 AM 5/28/99 -0700, you wrote:
|>Where does the intake air temperature sensor go on a turbocharged and
|>intercooled port injection system?  me
|
|before the turbo... usually in the air filter box.
|===========================================================
|           David Cooley N5XMT           Internet: N5XMT at bellsouth.net
|     Packet: N5XMT at KQ4LO.#INT.NC.USA.NA   T.A.P.R. Member #7068
|   Sponges grow in the ocean... Wonder how deep it would be if they
didn't?!
|===========================================================
|