VPC questions

[anomalyinva]

Can a mod edit out all of this bullshit bashing? There is good info in this post, but someone is gonna read two of the posts and just leave.

 

[VTEC-THIS]

HighPSI TSi Guy, VPC on a DSM went 7's.

And as far as the chip goes, you NEED the chip to go with your injector size. I know BR sells them for 50$, and they might make an arrangement to take on of your other chips in on trade for the 450...Who knows. Either way, I'd stay with the VPC, you have the largest portion of it already, and I know a LOT of the big names will take a VPC as their only option before a stand-alone. I saw a ton of 11-and 12 second 1G's this summer, and almost ALL of them had VPC's. Why stray away from the proven path? Especially if (like in this situation) cost isn't a factor.

 

[HighPSI TSi Guy]

Originally posted by VTEC-THIS
HighPSI TSi Guy, VPC on a DSM went 7's.

i thought so, but wasn't sure, i know buschur pulled a 7 before he wrecked but i wasn't sure if he was still on the VPC or not, for some reason i thought he had already switched to the AEM

 

[kpt4321]

Originally posted by HighPSI TSi Guy
it has many bugs left in it to be worked out. most of the good reviews are done by either ballswingers or flaming idiots that don't know how to tune in the first place so of course they don't notice a difference. because the car doesn't run any shittier than t already did.

This is the kind of shit that pisses me off.

What are all of these bugs you're talking about? I'd like to hear about them, really. All of the people I know running MAFT's that aren't complete ####bags, have awesome running cars.

I know how to tune, we won't go there.

My car runs better with the MAFT than it ever did without it.

VPC is proven to go 8s and has been a very accurate and great product for YEARS. you CANNOT outflow speed density either. it is a superior system. the MAFT is new, and s hardly near a finished product, and has yet to produce accurate results.

The VPC works very well, and can go fast. I will not deny that. I don not like the way in which it is executed, so I would not use one in my car whilst other options existed.

What do you mean, yet to produce accurate results?

I know a guy who dyno'd 400 whp on pump on a MAFT.

Another guy dyno'd 500 whp on a MAFT.

The fastest pump gas run TO DATE was made on a MAFT.

In another thread, you told a kid to put his SAFC settings to -44%, i hope the poor kid doesn't fuk up his engine because of you.

It was a baseline suggestion. He'll go out, tune, and adjust as necessary.

In my car, I have to lean it out to almost 40 percent, even though the formula only says 32 percent or something. It's not always dead on. I never claimed my estimatge would be perfect, you and I both know you can't tune someone's car from across the net.

now you are trying to tell this guy to ditch the VPC he already has for an inferior unfinished product?

I wasn't telling him to ditch the VPC, his was ALREADY BROKEN. In the case that he hadn't been able to find a cheap brain, I was suggesting he take his fuel management elsewhere.

Since he found a used brain for cheap, I think he did the right thing. On the other hand, if he had to spend 600 bucks or something for a new VPC, I would definately support the MAFT over it.

 

[HighPSI TSi Guy]

MAFT is a celebrity mod, of course lots of people are going to have it.. i didn't deny power can't be made on it, i jsut stated it is an unfinished and inferior product compared to the VPC.

the MAFT works for some people, doesn't for others, that's the way it is. i am not a fan of it because of this inconsistancy.

if you knew what the VPC actually costs you would have not suggested teh MAFT? don't speak what you don't know, simple answer to that one.

I don't like the EMS much either but it's fast too.

i am personally not sold on the MAFT and dno't think i will be any time soon. i have used it before and i love my 2G MAF much better.

what don't you like about the way the VPC is executed? you do know that your precious MAFT works in a very similar way, right?

the bugs in the MAFT i refer to are the correction knobs being "incorrect" (they don't correct the percentage they say they do) and just general inconsistancies. i found the 2G MAF to be much easier to get a consistant tune out of.

i'll leave the topic of that other guy alone, but you should know better than to suggest base settings so far on the lean side of things..

 

[kpt4321]

Originally posted by HighPSI TSi Guy the MAFT works for some people, doesn't for others, that's the way it is. i am not a fan of it because of this inconsistancy.

I have seen plenty of people go slow on the VPC and 2g MAF because they don't know what they are doing. That doesnt mean those products are bad.

what don't you like about the way the VPC is executed? you do know that your precious MAFT works in a very similar way, right?

No it doesn't. VPC is speed density, MAFT is a corrected hotwire MAF. Totally different.

Speed density is great in theory, but the VPC is not executed properly. It still works, but I don't like it.

the bugs in the MAFT i refer to are the correction knobs being "incorrect" (they don't correct the percentage they say they do) and just general inconsistancies.

Mine tunes just fine.

 

[HighPSI TSi Guy]

Originally posted by kpt4321
I have seen plenty of people go slow on the VPC and 2g MAF because they don't know what they are doing. That doesnt mean those products are bad.





No it doesn't. VPC is speed density, MAFT is a corrected hotwire MAF. Totally different.

Speed density is great in theory, but the VPC is not executed properly. It still works, but I don't like it.



Mine tunes just fine.

i know speed density is different than hotwire, but the way they work is the same, they both measure air their own way then calculate values to send to the ECU in Hz.

how is the VPC "not executed properly"?

 

[anomalyinva]

Like I said higher up, I ended up getting a VPC brain off ebay, from a fairly reputable parts dealer with like 800+ feedback at like 98% for $265 shipped.

 

[GRNDSM]

>Speed density is great in theory, but the VPC is not executed properly.
>It still works, but I don't like it.

Actually, speed density is a terrible system in theory… It does not lend itself well to modifications. For years, this has been a major gripe about it from techno geeks who want to have “ the latest and greatest”, but instead, were stuck with this 80’s technology… I have heard many people say stuff like “I like VPC, but I can’t bring myself to buying a SD system, instead, I think I am going to buy a PMS”… HK$ has defeated the common believe in this particular case and proved that speed density system CAN work.

As for two systems being different. Think of it this way, translator can send a signal of over 3000Hz to the ECU, while VPC maxes out around 2000Hz! That is a profound difference in MAS signal faking…

Leon
RR

 

[Mike 99GSX]

Originally posted by GRNDSM
>Speed density is great in theory, but the VPC is not executed properly.
>It still works, but I don't like it.

As for two systems being different. Think of it this way, translator can send a signal of over 3000Hz to the ECU, while VPC maxes out around 2000Hz! That is a profound difference in MAS signal faking…

Leon
RR

If the VPC maxes out around 2000hz, how did the guys running huge T4 turbos make them work when they had to be generating massive airflow numbers? I'm not doubting you, just wondering how this works exactly.

 

[GRNDSM]

Good question . I wondered the same thing... I believe that temperature has a lot to do with it. VPC sends a constant temp of 63deg to the ECU, where as other sensors also vary the temp.

Here is another thing to ponder. My VPC maxes out its Hz count at around 18psi of boost. I was getting the same Hz count on 14b turbo at 300whp (@18psi) as I am getting on a GT-13 with 491whp (@31psi).

I am not sure how it works as well as it does, theoretically, it shouldn’t… But it does!

That is why techno-geeks never liked this system .

However, those low Hz counts make ECU use better timing curves and that seems to give VPC cars more power!

Leon
RR

 

[kpt4321]

Originally posted by GRNDSM
Actually, speed density is a terrible system in theory… It does not lend itself well to modifications. For years, this has been a major gripe about it from techno geeks who want to have “ the latest and greatest”, but instead, were stuck with this 80’s technology… I have heard many people say stuff like “I like VPC, but I can’t bring myself to buying a SD system, instead, I think I am going to buy a PMS”… HK$ has defeated the common believe in this particular case and proved that speed density system CAN work.

I don't necessarily agree with you Leon. I think that, in theory, speed density is a good system. Its one major downfall is that you do have to re-tune if you change something that efects that airflow without effecting temp or pressure (cams, intake manifold, exhaust, etc), but once you get a car set up it's not as big a deal in my opinion.

If I were to buy a system like the AEM EMS, I would strongly consider using it in speed-density mode, rather than using a MAF. However, with the way the VPC is executed, and from what I have seen in VPC equipped cars, it's not the right thing for me in a street car. Not so much that it doesn't work, but I'm simply not comfortable with the way it does.

But, like you say, I am definately one of those "techno-geeks!"

 

[anomalyinva]

Oh well, I'll play with it some also using a SAFC II and if I can't get the car running like I want, sell both, and buy an EMS =P EMS backed 14b power can never lose!

 

[kpt4321]

Originally posted by HighPSI TSi Guy
i know speed density is different than hotwire, but the way they work is the same, they both measure air their own way then calculate values to send to the ECU in Hz.

Exactly. Hotwire and speed density are different.

They measure the mass flow, or calculate it, their own way, and not only that, but they also send it to the ECU differently. Leon mentioned this too.

Besides, the problems I am talking about aren't so much due to the theory behind it, as the way it is executed. In my opinion, the VPC is not the greatest design for a speed density system, and it has some features that have always bothered me. The few VPC cars I've driven were a bit lumpy off idle, especially when cold. The VPC also sends a very small Hz signal to the ECU, and seems to cap it.

 

[kpt4321]

Originally posted by GRNDSM
I believe that temperature has a lot to do with it. VPC sends a constant temp of 63deg to the ECU, where as other sensors also vary the temp.

Just a comment about this:

The MAFT also locks the input temp, but it locks it at 80 degrees. While this would mean its output has to be a little bit above the VPC's, it certainy does not account for the huge difference.

Leon, are you running a 550 chip? If so, that's another 20% lower signal, because the MAFT is calibrated to mirror the 1g MAF's curve.

 

[jdmawd]

Originally posted by anomalyinva
Oh well, I'll play with it some also using a SAFC II and if I can't get the car running like I want, sell both, and buy an EMS =P EMS backed 14b power can never lose!

if you need a vpc chip i have a stock 450 and 660 chip that im not using. i just changed to 720 injectors and a 720 chip. since you're local let me know.

 

[SpoOLxExO]

wow, this thread is pretty intense. It is good to have as much info as possible about the VPC since its becoming more of a "Mystery box" to some due to its discontinuation.

I have a stock chip for ya too. I'd be more than happy to help a fellow dsmer get his VPC running. Just as long as you don't attack me with a blistering assault of offensive "Techno-nerdisms" joking, don't get yer panties in a bundle!

I apologise to Leon for a deliberate here-say of his name without him present. Sorry, I was heated at KPT's response to an entire thread about the VPC, and not a maf translator.

In case you dont have the manual to your VPC, you can download or view it at this website:

http://www.rit.edu/~sjb2096/dsminfo_pages/vpc-gcc.html

hope it helps!