HKS VPC impressions

[pboglio]

I finally removed my HKS VPC (2g) after months of frustration with it. First problem, and the biggest was the following: Anytime I went to WOT the car would start knocking like crazy. That meant I could never go WOT for more than 2-3 seconds at a time.

The cause is that the VPC cuts off the airflow at about 2.47 gram/rev, regardless of what the engine demands. I usually pull 2.8 grams/rev in the midrange (measured before the VPC install), which means I go superlean because of the VPC airflow cutoff. This causes timing retard which kills power.

Now, when the VPC didn't cause knock it was probably worth 10 h.p. or so, but it was so inconsistent and the knock was so bad it was becoming a serious reliability problem.

Now that the VPC is off here are a few observations. There is no more idle lope, which was driving me absolutely nuts. I have much better part throttle power in the 2000-4000 rpm range. No more bogging when I let out the clutch in 1st gear, which was making it difficult to get off the line and keep up with traffic. In 1st and 2nd gear the engine now just explodes when the rpms hit 4000-4500 rpm, because I'm getting no knock retard. It is so nice to shift from 2nd to 3rd @ WOT and not have timing retard ruin all the fun. Its also nice to be able to datalog airflow in lbs/min again and actually get an accurate value, unlike the VPC which just estimates airflow.

I would never put the VPC on any car again, it is that bad of a product. I had a perfectly functioning VPC temp sensor and map sensor too and still had huge problems on my 97 GSX.

 

[talon_boy69]

HAHA damn...I also hate it...but well...btw, what dou you have now?

 

[UPGRADED2G]

I was looking @ purchasing a used VPC setup...NOT ANYMORE........DSMLINK sounds the safer(in terms of reliability) way to go, IMO.

 

[1993eclipseGS]

That was only two people's experience with the hks vpc though. You cannot really go by that. If you know how to use it, And know what you're doing.. It will work like it should. It's not the unit itself. A guy in my town used a vpc to tune his car, He ran 10.90's. This was installed on a 2gb gsx, Possibly 99, Maybe a 98.

 

[talon_boy69]

well..I'd say it is "excellent" for wot performance...but driveability sucks...some times it bogs, sometimes it do the idle fine, sometimes not, o2 trims while cruising(in my car) are too low...etc...it bogs when a/c is on...If I put the idle trim to 100, w/o a/c, when I turn the a/c on it goes to 140, and o2 trim still high...there are some consecuences because of guessing how much air is going into your engine...stand alones and some other speed density systems allow 2d and 3d maps for diferent loads...so that's the right way to go...also...at the new d-sport there's a dsm with maft, and the maf itself is DRAW throught before a PT67

 

[1993eclipseGS]

I guess it's different with different people and cars. I know when I was trying to tune with a maft, I was having problems, But alot of people said it's perfectly fine on theirs.

 

[talon_boy69]

I want to give this a try (www.maftpro.com) ...it is like a vpc but with 00' technology, instead of late 80's

 

[pboglio]

HAHA damn...I also hate it...but well...btw, what dou you have now?

I had DSMLINK V1 before the VPC, during the VPC, and after the VPC. Like I mentioned in another post, removing the VPC and going back to a stock 2g maf IS an upgrade The list of driveability and WOT problems with the VPC was as long as my arm.

 

[1993eclipseGS]

Why are these problems only occuring to certain vpc users, And not others? Is it the car and the user of the vpc?