HKS VPC guys check in please

I've never seen an IAT sensor go bad. There is practically nothing to them, just a thermistor. Most problems I have seen are mechanical ones, where the probe got broken off, or the wires are broken.
As I said, if the EMS uses a GM sensor, I'm pretty sure you could just use it for now, and then you don't need to reweld anything later.

 

[atc250r]

Quoting Darren:
Still messing with that VPC...... /ubbthreads/images/graemlins/banghead.gif VPC + Big cams + big injectors + big turbo = nightmare.

Dude just get yourself an EVO mas and a keydiver chip and call it a day.Not trying to be rude but you are never gonna get decent driveability with using A/C with your setup Mike.



I beg to differ. You can ask any of the guys around here that have driven my car. With the help of Jeff's chips in the ECU and VPC it isn't that hard to do. I was doing it with an SCM61 and 280's for a while but I didn't like the loss of low end from the 280's and went to smaller cams.

The sensor mount might be 1/8" BPT which is 1 thread per inch different than NPT. When I did mine I tapped the IC pipe 1/8" NPT and screwed the mount in. Maybe since it was only going through the relatively thin IC piping it worked even though the threads were slightly off but that difference in thread sizes is the same as when you put a standard US oil pressure gauge into our oil filter housings and I've had no problems there either.

John

 

Quote:
With the help of Jeff's chips in the ECU and VPC it isn't that hard to do.




I didn't say it can't be done,and I think the VPC is a great tuning tool if you have stock cams,550's ,and a 16G.

How are you dealing with the airflow cap with the VPC John? After 25 psi the VPC is pretty much done and caps airflow.

 

[Whistler]

Quote:
After 25 psi the VPC is pretty much done and caps airflow.



How did you come up with that number?

 

[NateCrisman]

I saw that myself in 2002 when logging the vpc map sensor through an fjo wideband's extra input. The his map sensor was at 5volts at 25 psi

 

[Whistler]

The sensor is advertised as a 3 bar, and should be good to 29psi. However, I have seen many HKS map sensors fail, including mine. I do not think that the HKS sensor is capped at 25psi by design. As a solution, I am currently using the GM map and with it the VPC is linear to 29psi.

 

[NateCrisman]

Well, I was logging the voltage and I remember it flatlining around 25 (on my autometer gauge). Raise boost over 25psi and a/f would just get progressivly leaner with more boost. It was a hassle to tune when tring to run 29-30 sinse af was never the same when boost would move around from one week to the next (track on car at the time)

 

Quote:
How did you come up with that number?



I saw it on the DSMLink board,logged map sensor and wideband sensor.The VPC also had the 660 chip in it.

 

[nrvous]

Sorry I am so late posting up.
I had the same problem with sensor not having enough to thread into. It happened at Watkins Glen while at the track, so I needed a quick solution. I ended up taking a band clamp, drilling a hole in it, and using that as that to sandwich the retention nut in place. Of course the intention was to get a bung welded on, and 5 years later I have only upgraded to a much nicer looking band clamp.
Hope it helps, but it can at least hold you over.


Stephen

 

VPC info site

 

Thanks for the suggestions and link, I'll take a look around there.

 

[BoostedAWD91]

Is there any places to get chips for the VPC still? I need one for 780cc injectors

 

[mooserage]

I thought you could just use the 550cc vpc chip in the vpc, and a keydiver 780cc VPC eprom chip? no?

 

[Nate]

You can use the any chip in the VPC with a keydiver chip, as long as you let Jeff know which chip is in the VPC.

 

[BoostedAWD91]

u dont have the use the keydiver though if u have the correct chip in the VPC, but do they make one for 780's?

 

[mooserage]

Iknow someone was running 720's, dunno about 780's though...

 

[BoostedAWD91]

nate thanks for the info, i didnt remember if they made on that big or not. Guess ill have to get a chip to run those injectors or go with 680's

 

You don't want to run the 660 chip. HKS only ever made a 450cc and a 550cc chip. The 660cc chip was a 550 chip that Buschur modified. All it does is remove even more output Hz to the ECU, which will cause bad knock issues on anything but C16, which is why Buschur sold it as a "race only" chip.
The ECU needs to see the proper airflow signal in order to calculate the load, to decide which AFR and timing maps to use. The more Hz you remove with a VPC, or an AFC, or a MAFT, the further off the maps you are. With 750cc injectors you would be removing >40% of the airflow signal Hz, so when you are boosting 20psi the ECU thinks you are only at 6 lbs of boost, so it uses WAY too aggressive timing advance and leaner AFR's.

 

[BoostedAWD91]

I honestly didnt know Buschur did all the chips above 550. Thats probably why it didnt work so great as it should have when i had it like 7-8 years ago /ubbthreads/images/graemlins/dunno.gif

 

[number3]

FWIW that o ring setup never leaked for me. I could fill up that IC system with compressed air upto 30 psi before I wussed out and stop pumping it it for fear my test rig would let go. I would hold that for at least 5 mins. AZ climate must be very different and hard on seals than PA for you to have all these leaks in oil and air.

Fo you VPC haters that car ran strong and more importantly safe with it. I am not saying there are not better options now but even just a few years ago an AEM could not be trusted not to blown your engine sky high via a computer glitch.

Good luck Mike and good job keeping her sound.