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JZA70 448 rwhp everyday
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Discussion Starter · #1 ·
i suspect that switching to a mkIV map sensor will effect timing. Can anyone comment on this? I mean if the air flow signal / maniflod pressure is less it only makes sense that the the timing would be more advanced? Any one have a timing log to proove / dispute this, i suspect that this is a dangerous mod.

~scott
 

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Well any mod is dangerous if not done correctly. Now i was told when i did the same swap of map sensors. This acts the same way the Lex AFM does for the 7m ... Just this time it's a little sensor instead of a large as pipe with the electronics ontop. As for me... All it did was lean out the fuel. and raised the boost cut. I am using JDM 2jz-gte 440cc injectors. Mine are Hi-impedance(sp) so they are plug and play.
 

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JZA70 448 rwhp everyday
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2,994 Posts
Discussion Starter · #3 ·
i understand that the mkIV sensor is made for larger injectors, once warm the O2 sensor will likely curve the air fuel ratios to 14.7 exept at WOT which one can tune out with any piggybak. Im asking about TIMING.

~scott
 

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bump.

Does anyone have an answer for this. I'm using mkiv 550 injectors and a mkiv map and my car seems to run just as stock. My mpg isn't much different than when the car was stock.

Edit: said is instead of isn't
 

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JZA70 448 rwhp everyday
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2,994 Posts
Discussion Starter · #5 ·
how is it different, i suspect that it would get better? And yes map sensors do have an impact on timing we need to figure out if this is safe. If I have to ill get a timing light and see myself but it wont show differences on boost which is where it counts.

~scott
 

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Well I have checked the timing at idle and it seemed to be just fine. But now it could change the timing under a load at a higer rpm.

Sorry I mean to say isn't different on using more fuel.
 

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JZA70 448 rwhp everyday
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2,994 Posts
Discussion Starter · #7 ·
thanks for the edit, are there any good timing gauges or recorders out there? It would be interesting to see the differences and a good timing monitor is the only way to do it.

~scott
 

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Not so boring anymore
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if you mess with the preceived load (adding a bigger map sensor so the ecu is seeing less boost) you are 'messing' with the timing maps.. its putting timing for 10 psi when its really at 15 psi (just an example)... its the same think is pulling some fuel via an afc...
 

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JZA70 448 rwhp everyday
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Discussion Starter · #9 ·
its exactly the same concept, I just wonder how much timing is affected.

~scott
 
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