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zippy

IAT Location

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Here is why the IAT sensor location is important.

 

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Instead of the timing being reduced as the truck goes down the track as the air charge heats up the timing will remain the same. As the air heats up on the boosted side KR* becomes closer and closer to happening. On a system with the IAT sensor on the non-boosted side of a boosted system the sensor will actually report the air as cooling off as the air begins rushing in harder. On a system where the IAT is on the boosted side the sensor will actually report the rise in IAT and allow the computer to reduce timing to prevent detonation. The posted log pic with almost no KR* duriing the pass is a Radix boosted truck that has the IAT sensor on the boosted side allowing for self timing retard. A considerably safe system and kudos to Magnacharger for doing so. The log showing a considerable amount of KR* is a Vortech powered system. The Vortech system isn't set up for a boosted IAT. Their system of protection is to run a very low timing curve. The problem only becomes worse with a smaller pulley as the air goes past the maf even quicker causing the pcm to see even quicker reduction in IAT when what is actually occuring is a quick rise in IAT bringing on KR*. Hopefully some results will be posted soon of a properly setup Vortech not only gaining some time in the quarter from simply having the computer see what's happening, but making sure that the engine doesn't have issue's from a simple flaw in design.

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Man, I get KR all the time... sometimes when I go WOT (4th to 3rd downshift) I get up to 7* KR, and it starts to taper down. I usually get 3-5 KR all the time... is that not good?

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lol thanks for posting this , explains why its so important . i wonder whos log that is ?? :D well good news is i have the iat in hand and the it should be going in within the week, i just need to find someone that can weld aluminium well. cant wait to post the results .

 

p.s. you like that inj duty huh??

Edited by 04CHASE

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Jeeze man...why didn't you tell me all this when I had the vortech? :jester:

 

 

 

I actually think I recomended you moving it adam, but I think it was just before you'd taken it off. :jester::banghead:

 

I would say it's not a good thing punkt. Not only are you losing power when it happens, but it can cause a problem over time mechanicly. :(

 

 

 

Deffinitly yours Chase. I've found nothing else that max's the maf quite like yours does with the stock 6.0L in it. Almost your whole pass has the maf maxed. lol :driving:

  • Upvote 1

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Jeeze man...why didn't you tell me all this when I had the vortech? :jester:

 

 

 

I actually think I recomended you moving it adam, but I think it was just before you'd taken it off. :jester::banghead:

 

 

Man....the hits just keep on coming. :lol::jester: Damn I need my new motor to eese some of my pain. :cry::D

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Man, I get KR all the time... sometimes when I go WOT (4th to 3rd downshift) I get up to 7* KR, and it starts to taper down.  I usually get 3-5 KR all the time... is that not good?

 

 

This is probably the infamous SS false KR caused by tranny shifting noise, but it would pay to check it out. Run some high octane and see if it goes away. If it doesn't search for "false knock" We had a lot of discussion about 1.5 years ago or so (and found out how to tune it out -- which I don't remember anymore ;))

Edited by TurbochargedBerserker

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Man, I get KR all the time... sometimes when I go WOT (4th to 3rd downshift) I get up to 7* KR, and it starts to taper down.  I usually get 3-5 KR all the time... is that not good?

 

 

This is probably the infamous SS false KR caused by tranny shifting noise, but it would pay to check it out. Run some high octane and see if it goes away. If it doesn't search for "false knock" We had a lot of discussion about 1.5 years ago or so (and found out how to tune it out -- which I don't remember anymore ;))

:withstupid:

from what ive read first pour some good high quality octane boost (run a search theres actually one that is good and works) if that doesnt do it then try the false knock problem.....either way you might benefit from having it personally tuned well

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I will look into that. I notice I start to get a lot of KR when I am on the freeway, and I give it some gas to change lanes/pass, and right before the converter unlocks the KR shoots up to almost 7KR (this is not WOT... but about 50% throttle, just enough to get a dowshift) I was thinking I might need to tune the converter to unlock with less throttle % or something...

 

Also, whenever I am WOT in 3rd, and the TCC locks up (at 90mph) it almost instantly goes from 1-2KR to 5* KR right when the converter locks.... is this something that can be tuned out?

 

Thx

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Where are the IAT's on your logs? I can't see them for a comparison :dunno:

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Where are the IAT's on your logs?  I can't see them for a comparison  :dunno:

 

 

The log doesn't show the IAT's, but it does show the timing issue. The Radix log slowly pulls the timing as the IAT's heat up where as the Vortech log doesn't pull timing away for any reason other than KR*. I could send the files to you though.

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The log doesn't show the IAT's, but it does show the timing issue. The Radix log slowly pulls the timing as the IAT's heat up where as the Vortech log doesn't pull timing away for any reason other than KR*. I could send the files to you though.

 

 

Not necessary boss but thank you :cheers: I have always wondered if my IAT sensor reacts quickly enough to even give a representative value for that comparison. Either way, I rarely hit the level where timing will be pulled due to IAT.

 

I think I read somewhere where the Vortec intercooler is much more efficient than the Radix. Was that Vortec's justification for this (in addition to running a soft timing table)?

 

Anyway, IMO the IAT sensor should be as close to the engine intake as possible for the most representative air sample. At the very least on the boosted side, basic engineering principles apply there. Was never really sure why it is located in the MAF sensor to begin with.

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I believe they did it from the factory to eliminate one sensor an make the truck run better if the maf does fail. With the IAT in the same place as the maf the system can similate the maf being there in calibration alone if the maf fails.

 

The stock intercooler for the Vortech is very efficient, but once you begin cranking the boost up heat is going to happen reguardless. I'm assuming that with a soft timnig curve and the boost at stock levels it's rarely a problem. I sure don't understand why a company would release their product like that though.

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i wish it would show the iat on the chart i have a new log with the iat on the boosted side, all in all it was pretty easy to do just got a new sensor and bung and had it put in. the highest i saw on a wot run from 0-110 was about 145 iat temp , and after i let off it drops back down very quicly , now i just need to make the i/c more efficient . hopefully track results to be posted with the iat relocated soon.

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