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Newbie
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Discussion Starter #1
Just stumbled across a post made by Dusty where he mentions no one should run a vpc/safc, but instead should run a vpc/gcc combo.

I've usually hear people dump the gcc in favor of the safc w/ the vpc. The safc simply has more tuning points and you can set the rpm at which the changes are made.

So, why the gcc over the safc and have any NA-T gone the vpc/gcc route? Don't believe I've heard of anyone going this method.
 

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I use a GCC and find it to work well. I can't find any search results that give reasons why anything else won't work. It really doesn't matter at this point and I could care less but it seems to be a sore topic.
Someone who has o-scoped the signal with a GCC and with a HKS Super AFR could speak-up I suppose but I'm not going strickly on the information that many incorrectly wire the devices or that one should stay brand-loyal (never mind I own nothing but HKS devices). The only thing I've done is log the OE AFM value in the ECU (g/sec) and compare it later with the same signal based on VPC/GCC input. This says nothing of the quality of the signal only that it tracks well enough against load. I can say that what I saw looked better than that described by several members (very old posts I might add) stating that the signal quality was for shit coming from the VPC/GCC and that it cleaned-up well after running the VPC through a S-AFC. Of course this contradicts what you heard doesn't it...
 

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King of the NA-T's
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I used a VPC/GCC, but then punted the GCC for a SAFC. The GCC doesn't have HI and LO maps, so any correction you try to do with the GCC affects both closed loop and open loop. I found the SAFC worked better because I could keep from messing with the ecu at low throttle settings, and just tune the WOT maps.
 

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Here is the "other" opinion on using the SAFC with the VPC.
8secsupra said:
I dont think Dusty was trying to sell the MAP ECU specifically, he was simply pointing out that the VPC/SAFC/SFC combo is not the most reliable tuning solution, not to mention its old technology now. The VPC has a rock solid output signal to the ECU, but when you intercept it and modify it using a non-HKS product, many times it tends to corrupt the output signal and/or delay it. This corruption and delay is sometimes more than enough to cause intermittent tuning issues. It also depends on the end-user wiring of the unit into the HKS wiring, which most of the time is sub-par at best. The GCC was a direct integration into the VPC harness, and worked every single time with super reliability. We found this to be true time and time again, much the same as the old FCD signal corruption debate of years past. But, once again, this is OLD news. The VPC has been out of production for years, and this is a MAP ECU thread, so lets move on.

Thanks,
 

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I ditched my GCC for the SAFC2, car ran perfect and it was very easy to tune. That is the combo I used when I put down 390rwhp @ 10psi
 

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kirk- do you have anyway of looking at the signal going into the ECU? This is what is being argued on another thread- signal integrity and possible time delay issues.
 
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