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Discussion Starter · #1 ·
Has anyone looked at a log to see how much nitrous lowers the air intake temperature? I've read it can drop it as much as 70* !
 
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Discussion Starter · #2 ·
Well, since my intake temp sensor is upstream from my nitrous injection, I don't think I'll see much difference on the data log.

You'd have to calculate how much the temp is dropping by taking the mass of air coming in and its temp, and averaging it with the mass of nitrous coming in, and its temp (which is normally about minus 125 deg F). That doesn't take into accout the different latent heats of the two gasses, but I doubt they'd be different enough to bother with.

At WOT my MAF reads about 350 grams per second of air. My nitrous injection is set at 100hp, which works out to about 30 grams of nitrous per second. If the intake air is at say, 90 degrees, and the nitrous is -125 degrees, then the average intake temp works out to about 73 degrees - in other words, 2 tenths of the improvement I get from nitrous comes from its cooling effect, the other 8 tenths from the juice itself.
 
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Discussion Starter · #3 ·
yep.... mine went from 90* to 27* ... You guys running your Nitrous after the sensor may want to think about moving it... I think the computer uses the temp and O2s to adjust fuel ... :D
Kenny
 
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Discussion Starter · #4 ·
Kenny actually when you go WOT it only uses the WOT fueling table and spark table, the computer goes open loop.
Just FYI.
Mike
 
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Discussion Starter · #5 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by 4DRHTRD:
Kenny actually when you go WOT it only uses the WOT fueling table and spark table, the computer goes open loop.
Just FYI.
Mike
<HR></BLOCKQUOTE>

nope Mike :D... That was true on older cars but trust me, the car is in closed loop and stays there through-out the run .. If anyone can read a DIACOM file and would like to look at that run .. shoot me an email and I'll send it to you ......When I'm fine-tuning a car for WOT .. I don't do it in the WOT table :D ... Mostly in the power enrichment table, and a few others :D

Kenny
 
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Discussion Starter · #6 ·
I was just looking at my runs from SLP ( link in sig) in Orlando and my intake temp went from 109* to 28* ... HOLY CRAP !!!!! 81* drop ... WOW ! that's some good air . :D

Kenny
 
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Discussion Starter · #7 ·
Sorry Kenny I shouldn't have said WOT table, that's the table for adjusting where you go WOT by percentage. You are using the open loop fueling table by adjusting RPM vs Power table. That table only comes into play when at WOT:

PE vs. RPM

This table contains the Power Enrichment (additional fuel) that will be added at WOT vs. the current RPM. This is typically where fuel tuning for WOT operation is done. Values can be positive (Adding fuel) or negative (Subtracting fuel).


The reason why the O2's don't bounce around anymore when at WOT is that the car has gone open loop and no longer is trying to correct via O2 sensors.

Just FYI.
Mike
 
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Discussion Starter · #8 ·
A little more info on this:
WOT Table This is the percent TPS that will be required for the WOT bit to be set in the computer when the engine temperature is less than 151 C. This can be altered so that the computer is always in PE mode at idle rpm’s (thus O2’s are ignored) if so desired.



PE vs. Coolant Temp

This table contains the Power Enrichment (additional fuel) that will be added at WOT vs. the coolant temperature when in PE mode (WOT)



PE vs. RPM

This table contains the Power Enrichment (additional fuel) that will be added at WOT vs. the current RPM. This is typically where fuel tuning for WOT operation is done. Values can be positive (Adding fuel) or negative (Subtracting fuel).

Mike
 
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Discussion Starter · #9 ·
Here's a tidbit from Christian:

Hi Everyone,

Closed loop refers to the O2's being warmed up enough for feedback, not that
the feedback is necessarily being used.

The open loop table is like a choke, used until the O2 can warm up for
feedback (cold start if you will.)

The PEvsRPM table is used regardless, that's the majority of WOT AFR tuning.


Can both the open loop and pe table be used? -Sure, if the car hasn't warmed
up to closed loop both are used.

Make sure the people having the debate are clarifying themselves.

Hope this helps avoid confusion,
-Christian
 
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Discussion Starter · #10 ·
Sorry, I'm probably killing this one but here's one last reply:
When PE is activated the computer no longer learns or adjust fuel mixture
using the O2s....... (open loop) the reason for this is a good power
misture is about 13:1 while 14.7 is best for emmissions and fuel
economy.....u dont want the computer learning during this enrichenned state
 
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Discussion Starter · #11 ·
Keep it coming Mike, I just about understand.
I have to replace my O'2's every 3-5 tanks of fuel because of the lead. during the period in between is that bad?
They go way off scale low.
 
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