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I was wondering if anyone has any proof that the vpc helps? People say 20 hp and some say more... i also will have a fuel controller.... any help is appreciated... dont want to waste money and time.... Kevin..
 

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Good Question I've been wondering the same thing? What about front mounts on stock twins? Some say they've seen a 25hp incease w/ a fmic. I know fmic are a must when going single do they do any good w/ stockers?
Later
 

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Well, here is a run without a VPC that did 405/438 on the dyno. This was with a Greddy SP and the next run that I am going to post I had a VPC but had stock exhaust and still gained hp especially on the upper RPM's.
 

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Here is my 425/456 run with the VPC on and back to stock exhaust. You will notice by comparing side to side with my 405/438 run from the previous post that it did not only gain peak numbers it did better in the upper RPM's as well.

Hope that helped.
 
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Go to boostaholic.com he put on a greddy fmic and said he dynod almost 50rwhp... may have had a ic leak but his car really picked up with the fmic.... hey tt6spd what tires where you running on the 11.26 .... thanx Kevin... did you put stock exhaust back on then use the vpc or what....kinda confusing... looks like on the graph you lost peak rwhp and kept it better across the rpms thanx...
 

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Kevin Hornsby said:
Go to boostaholic.com he put on a greddy fmic and said he dynod almost 50rwhp... may have had a ic leak but his car really picked up with the fmic.... hey tt6spd what tires where you running on the 11.26 .... thanx Kevin... did you put stock exhaust back on then use the vpc or what....kinda confusing... looks like on the graph you lost peak rwhp and kept it better across the rpms thanx...
I ran on ET Streets.

I didn't lose peak power. On the first dyno run of 405/438 was with Greddy SP exhaust and NO VPC...on the second dyno run of 425/456 was with VPC and stock exhaust. Not really sure what you are talking about I guess when you say that I lost peak power. Please explain and I will try and clear it up better.
 

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Here's a dyno with my car BPU with and w/out VPC. This dyno was done before my FMIC. I picked up about 25 horses and better breathing on top end. You can see my hp and torque didn't tale off on the top.
 

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The VPC gives you more power, but it's mostly due to adjustments it makes to the fuel curve rather than the elimination of the MAS. Supras run extremely rich up top, and if you can lean the fuel curve out somewhat with a VPC, AFC or other fuel controller, you'll pick up power. David Buschur posted the results of a bunch of tests he did on his dyno, and one of the things he did was to dyno his VPC equipped car with and without the (disconnected) MAS in the intake:

So the difference between with and without the MAS is 2 HP peak and about 7
HP at 7,000 rpm. Not much to talk about at all.


If you already have a fuel controller, the VPC is a pretty expensive way to gain a couple of HP.
 

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Eric said:
The VPC gives you more power, but it's mostly due to adjustments it makes to the fuel curve rather than the elimination of the MAS. Supras run extremely rich up top, and if you can lean the fuel curve out somewhat with a VPC, AFC or other fuel controller, you'll pick up power. David Buschur posted the results of a bunch of tests he did on his dyno, and one of the things he did was to dyno his VPC equipped car with and without the (disconnected) MAS in the intake:

So the difference between with and without the MAS is 2 HP peak and about 7
HP at 7,000 rpm. Not much to talk about at all.


If you already have a fuel controller, the VPC is a pretty expensive way to gain a couple of HP.

When he did a before and after...what were the air qualities of the two different dyno sessions before and after the VPC mod?

When I put the VPC on my car the a/f ratio was still waaaay rich, just like before the VPC....that was with the the VPC zeroed out, and I still gained 20rwhp peak, and quite a bit more up high...it would just allow more air into the engine.

The best tuned AFC, BPU car will not outperform a well tuned VPC, AFC, BPU car....that is the bottom line on the difference between having a VPC and not having a VPC.
 

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TT_6SPD_95 said:


When he did a before and after...what were the air qualities of the two different dyno sessions before and after the VPC mod?
I'm pretty sure the pulls were back to back, so the differences in air quality were minimal.


When I put the VPC on my car the a/f ratio was still waaaay rich, just like before the VPC....that was with the the VPC zeroed out, and I still gained 20rwhp peak, and quite a bit more up high...it would just allow more air into the engine.


The best tuned AFC, BPU car will not outperform a well tuned VPC, AFC, BPU car....that is the bottom line on the difference between having a VPC and not having a VPC.
Dunno. David knows what he's doing, and dynoed the same car on the same day with and without the MAS in place and got 2 hp. He's actually a big VPC fan. He sells lots of them for DSMs, and his 8 second DSM is still running one with a factory ECU, so it's not like he's biased against them. His car wasn't making big power for a BPU car though, so it might make more difference on a car making 40-50 hp more.
 
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