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512RWHP... 503RWTQ... 7M
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3,292 Posts
Discussion Starter #1
This may be really directed towards you guys with out the AFMs...

Anyway, I dont have an AFM, using MAF or MAP (right?) with the VPC, and it's the first time Ive had a car like this so the thing is: she hates the cold starts... When she's cold, throttle response isnt great, kindy bumpy :blah: :blah: :blah: But when she warms up, forget about it, she's haulin ass, idles super smooth and all that...

My question is this: is that normal? Does it have to be a little warmer before everything smoothes out? Or is there something I can do to help with this initial start up bumpyness?

Thanks,
Jake
 

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Do You Even HKS, Bro?!?
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1,493 Posts
First, you are either going to have a MAFT, MAP, or VPC, not a combination of...each one does the same thing (gets rid of the AFM).

It's normal for turbo cars to have to heat up before being able to floor it. (try a carbed car if you think that's bad)

Kevin
 

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512RWHP... 503RWTQ... 7M
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3,292 Posts
Discussion Starter #3
Thanks Kevin... Yeah, this is new to me... I just learned a ton about AFMs, and now Im venturing into this... *time to learn, lol* Well, I guess I have VPC, using the HKS VPC...

I just dont remember it being this tempermental using the AFM...

Just came up with a question: whats teh benefit of using the VPC/MAFT/MAP over the AFM? :D
 

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I don't want an MK4!
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1,727 Posts
I think there might be a benefit upwards of 450HP against the Lex. The AFM is a restriction, I am just not sure where that restriction comes into play. 450 or over is my uneducated guess.
 

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SP74HO
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1,143 Posts
Yeah, let it warm up abit first. Mine runs and shakes like a fat hooker on a cold night, but after she warms up, look out!
 

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Registered
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I have the same issue. I just let my car warm up 5 to 10 min before I drive it if it is cold
 

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No One Ever Listens To Me
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5,467 Posts
jake you shouldnt be boosting the car until its warmed up anyways...you should know better :nono:
 

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512RWHP... 503RWTQ... 7M
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3,292 Posts
Discussion Starter #8
Jayson you know its a lag monster, I cant boost it, :lol: j/k... Im not really talking about boostin, just like fstoy said, it just kinda "runs and shakes like a fat hooker" when cold, :lol:
 

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Back to boosting!
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339 Posts
Hehe, mine takes a bit to warm up too...oh wait, I have no IAC...hahahahahahha
When I fix that problem (it's on the list, trust me) it should start up and idle just fine when cold. That may be a while tho... Anyway, back to the topic - since it's a maf to map conversion, the computer doesn't actually see the air goin into the motor. The vpc converts a map and temp signal into a guess as to how much air should be going in and tells the ecu that's what's happenin. It ain't a perfect system, but that's life with no afm.

EDIT: Oh yeah, the benefits? That big ass 4" intake you got on that turbo instead of the tiny little afm housing. More efficient, less restriction, more flow. Plus you can have that big ole 9-incher in there - size does matter :D:D
 

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No One Ever Listens To Me
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animantoric said:
Hehe, mine takes a bit to warm up too...oh wait, I have no IAC...hahahahahahha
When I fix that problem (it's on the list, trust me) it should start up and idle just fine when cold. That may be a while tho... Anyway, back to the topic - since it's a maf to map conversion, the computer doesn't actually see the air goin into the motor. The vpc converts a map and temp signal into a guess as to how much air should be going in and tells the ecu that's what's happenin. It ain't a perfect system, but that's life with no afm.

EDIT: Oh yeah, the benefits? That big ass 4" intake you got on that turbo instead of the tiny little afm housing. More efficient, less restriction, more flow. Plus you can have that big ole 9-incher in there - size does matter :D:D

1) our cars dont have MAF they have AFM there IS a difference

2) the ecu sees the air coming in fine...if it didnt it wouldnt run at all...the VPC converts to KV for the ecu to read off of...admittedly the VPC signal can be a bit grainy but the AFC2 is hooked up inline and cleans it up for the ECU
 

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Back to boosting!
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339 Posts
IdealSupra said:
1) our cars dont have MAF they have AFM there IS a difference

2) the ecu sees the air coming in fine...if it didnt it wouldnt run at all...the VPC converts to KV for the ecu to read off of...admittedly the VPC signal can be a bit grainy but the AFC2 is hooked up inline and cleans it up for the ECU
Leave it to ideal to have to argue about everything. So nitpicky :rolleyes: !! I'll leave #1 alone, but I think you misunderstood #2. The ecu doesn't see air with it's own cal'ed sensor, it gets the VPC's guess as to what it should see. Slight approximation = not quite as perfect as Toy meant it to be. Eh, works fine when it's warm tho...like my car...mostly...
 

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Super Moderator
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10,150 Posts
My VPC car is cranky when cold, my guess (and its just a guess) is that the VPC ROM's were tuned with the warm running map in mind, the stock ECU *does* have a different/altered map for colder coolant temps and hence it gradually gets to perfect once the car is totally warmed up.

I let it idle for a good 30 seconds before driving and its a lot better.
 
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