Dominic Sorresso

Since I am using a Aeromotive VAFPR, I have been playing with the BPC table to try and address a "wavy VE table". The EBL bin comes with tthe BPC Filter% set at 37.5. Reading the cal information, the lower the %, the greater the lag of the BPC change. Anyone else running a VAFPR change this filter?
If so to what? I'm going to try and raise it then datalog. I'll report my results but I'd be interested in anyone else's results. RBob, any guidance on this?

V8Astro Captain

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I have the 13301 Aeromotive VAFPR. My BPC filter is at ~50%. This helps because the regulator changes pressure quickly.

I have doubled the filters for the AE TPS and MAP. This helped tremendously in keeping the fire inside the engine and not coming out the intake :eek!:

Dominic Sorresso

Mic,

Just got back from a ride where I had bumped BPC filter from 37 to 53%. I could notice the difference right away. It was very much like driving the car for the first time using the VAFPR vacuum port connected. That first time I noticed how much more repsonsive the throttle was. Well increasing it 16% made the same kind of difference. In fact, since I have the Ostrich attached, I bumped it again mid way thru the drive and increased the filter to 65%. The throttle response is instantaneous. the slightest pressure on the accel, and you can hear the motor change pitch. Maybe RBob could chime in and tell us when its too much of a good thing on the BPC filter.

V8Astro Captain

iTrader: (1)

Do you have the same regulator? If you do, which spring is in it?

I'm running the high pressure spring rated from 20-60 psi. It worries me tho, I idle at 16 psi and at 100 kPa I'm at 25 psi. I'm worried the response is affected taking all the load off the spring under vacuum.

...just wondering what you got goin on...

You have a WB O2 I think. Go put a Weiand 142 on your Vette real quick and tell me HTF I get fuel in this beast in closed loop lol

Dominic Sorresso

Mic,

I'm using the same spring you are. I wish Aeromotive made something in between. My WOT is at 20psi. My decel gets down to 8psi. I just checked the FP the other day using my Mity Vac and the pressure tracked pretty accurately with RBob's calcs even down to that level.
Yeah I have a ZT-2 WB.

Dominic Sorresso

Anybody else wanna chime in?

liquidh8

Guys, I have a factory style VAFPR, the marine BBC TB type. MY FP is 15psi @idle, 24psi WOT. I have moved the BPC filter around from the 37% to 95% and all in between, and to be honest, I haven't "felt" any difference. What I should do is datalog a few drives to work with the BPC filter at both extremes, ie, low % ike 35, and a higher % like 90. Just to see if something changes in the datalog. though I am not quite sure what to look for as far as changes.

Dominic Sorresso

liquid,

I have found that increasing the BPC filter gives me better, more subtle throttle response. Right now I have it set at 70%. I'm thinking I'll leave it there because I didn't feel any difference between 65% (previous) and 70%. The change to 65% was much more pronounced. My "wavy VE" table has gotten "wavy-er" but the motor seems to really like it especially after putting on about 50miles to the new calibration. The INT settles down and the BLMs are steadier and more consistent. Its worth playing with it especially if your motor is modded and the MAP/VAC changes much more quickly than a stock motor. That's what led me to play with it in the first place.

V8Astro Captain

iTrader: (1)

I'll wager a guess and say you can feel smaller filter differences with a manual trans.

Dominic Sorresso

Good point. And I think a torquey motor will also respond well to it.
Still waiting to hear from the Grandmaster RBob.

liquidh8

For a while there I had it a 90%. And tuned around with that. Then I lowered it again to under 50%, and left it. I'll have to datalog with it. First I have to install the autometer FP gauge, and run a lead to the EBL so I can datalog it. I think I'll be able to see a difference in the log better with the FP too.

va454ss

iTrader: (1)

I bumped mine to 65%. Phenominal increase in throttle response.

Dominic Sorresso

Maybe we're on to something here.

Ronny

iTrader: (1)

Hi Dom:

Thanks for doing some of the preliminary research for us for VAFPR applications!

My car is out of storage soon so I may be calling !

Reading through this post something peaked my interest.

Is there a need for more definition in those tables?

If that were done could the filter be set to a lower %?

As you are aware RBob expanded the AE as it was clear that was needed. Possibly here as well.

Also what if you run OL so the BLM's do not impact the VE tables? maybe as an experiment only

Pre -EBL it was once postulated that running a VAFPR was difficult as the MAP/TPS swung so wildly with typical automobile daily use and that maybe more suitable for marine use(linear load?). with EBL available now it has greater value in some of our applications.

Fast355

iTrader: (2)

The VAFPR is not really a VAFPR at all, it is just a marine application regulator, with a FIXED pressure. The tube that we all hook vacuum to is actually a safety tube that is aimed down the throttle bore in case the diaphram ruptures. This keeps the bilge from collecting the fumes and the boat from going BOOM!!!

Dominic Sorresso

Ron,

Your welcome to drive down to Chicago and visit.

Don't think the BPC v VAC table needs to be expanded. It already uses increments of 5kpA. Seems fine to me.
I ran O/L when I first started tuning EBL. I used the WB function in Learn VE to rough in the VE tables, then swittched over to C/L and BLMs.
Without EBL, it wasn't possible to run a VAFPR because the 7747 code made no provision for a changing BPC due to Vacuum. EBL code does. I think I have mentioned to you before that using the VAFPR results in much crisper throttle response than using a constant FP and BPC. Not to mention it helps cure the PW issue at idle. Now I have played with the BPC filter in the EBL code and found that raising it enhances throttle response even further.
Ron, when you finally hook the VAFPR up to vacuum, you'll know what I mean. I decided to increase the BPC filter because it seems that events in a modded motor happen significantly faster than stock. And I felt that the BPC needed to respond more quickly to vacuum changes that were happening already much quicker than "normal". The hypothesis proved to be true in my case. The motor responded very well to this. I think you'll be happy once you try it.

va454ss

iTrader: (1)

Previously, I was using a 7060. The code had a patch for the use if the vac regulator. It was not adjustable, but was set up for the GM vac reg. Not sure of the exact filtering.

I swapped cams just prior to installing the EBL and really haven't spent much time on the tune. This change made a huge difference and now feels more like it should.

I originally thought my loss of throttle response was the result of the cam change.

Glad I made this adjustment before playing with TPS enable, pumpshot, etc.

Thanks again Dom!

RBob

iTrader: (1)

This is an interesting thread as it sheds some light on the response time of the Aeromotive FPR. Not sure what to think of the GM marine style regulator.

To better understand how the BPC changes and the resulting PW changes I put some graphs together. This is from an actual calibration that is being used. The graphs show a step response from 60 KPa to 90 KPa at 2,400 RPM (for the VE% values).

A step response was used as it is easy to calculate for. And it shows the BPC & PW values without having a sloped MAP value thrown in.

The first graph is the BPC vs Time (each tic mark is 12.5 milli-seconds) with various filter values. The 100% value is no filter action. The BPC follows the vacuum. The 300 milli-second mark is 3 tenths of a second.

At the same time the driver hit the pedal and the MAP went from 60 to 90 KPa, the fuel pressure regulator also started to increase the fuel pressure. The ideal situation is to have the BPC value follow the increase in fuel pressure one for one. If there is a difference between the two, then the fueling will be under or over.

In the second graph the PW is plotted vs time. Note the blue line for the 100% filter. The PW goes from 2.1 ms to 3.4 ms in one tic (12.5 ms). If the fuel pressure changes at the same rate then this is an ideal filter value (100%).

Then as the filter value gets smaller the PW peaks higher. This is going to add fuel as the filter values decreases. And the opposite, the fuel will decrease as the filter value increases.

RBob.

va454ss

iTrader: (1)

Interesting.............

I am using an Aeromotive regulator but not the 13301 everyone else seems to be using.

I'm using the 13107 (designed for LT1 apps).http://store.summitracing.com/partde...5&autoview=sku

Don't know if the response would differ between the 2 or not.

Also running a bit more fuel pressure than most. Not that I need it right now, just seeing what I can get away with. Plans are for more cubes.

Even if the BPC filter were off a bit, couldn't it be compensated for with the VE tables (to a degree)?

RBob

iTrader: (1)

There along with the AE tables. A too slow a BPC filter will cause additional fuel to be injected. This is while the throttle is opening or the engine load increases.

RBob.

Dominic Sorresso

va454,

That's how this thread got started. liquid8 and I were discussing "wavy ve tables", and I began playing with the BPC v VAC numbers figuring that by raising the BPC at a particular VAC kPa, I could lower the VE and so smooth out the VE curve. Fast355 said he'd used a vacuum pump to determine the FP coming from his VAFPR for each increment of VAC rather than using the calc'd BPC from RBob's .xls. So I thought I would try that and found that at least my Aeromotive VAFPR didn't react exactly as calc'd. Some spots it matched the calc'd FP and in some it didn't. I'm now using the actual FP numbers to determine BPC. Finally, I spotted the BPC Filter% and thought I would try to modify, figuring that vacuum in a modded motor would change more rapidly and abruptly than a stock one. I felt the BPC changes needed to closely track the vacuum "ups and downs". In my case, the throttle response improved significantly.
To answer your question, you could play with the VE tables, but I don't think the throttle response would be the same because the INT and BLMs aren't going to react as quickly as the change to the BPC. RBob or Bruce can check me on that.