Overboost protection with LDA?

[foxracer1]

I was looking over the description of the VE pump on  URL this site would if the pin was modified that at a set boost level it would begin to reduce fueling? It could increase like it does now but at the top there would be a ramp the would push the throttle back when/if the boost went over the set PSI?

I imagine this would be easy to do if we had a pump test bench as we could produce the conditions we need with out the differences in road conditions and testing procedure.

Does this sound feasible? I know the waste gate works but this would help reduce wasted fuel and create less heat.

Its to early Ineed to go to bed i'm goin crazy. I don't even have a TD pump to play with or a td engine for that matter.

[foxracer1]

Maybe a 1.9 boost pin would work so the ramp could be lower tha a modded 1.6 pin to keep the pin within its normal travel. I drew this up in paint.

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[pernalonga]

Hi there,

I think u get the same effect by tuning the wastegate to the desired pressure.

On the other hand: the injection pump starts cutting off fuel delivery as it's rotation goes higher  - up to around the Red line.

What is exactly your idea ??

Regards

[RabbitJockey]

why would you want to put less fuel?  bad idea imo.

[foxracer1]

It would reduce fuel to control boost, and eliminate waste of excess fuel when the wastegate is open. When the waste gate is open the IP is still dumping that fuel in there creating excess heat and using fuel that is serving no purpose. It would balance out creating enough fuel for the desired boost. You could still adjust it so if you still wanted a little extra fuel while at max boost. Its mainly to try and save fuel.

This may be more benficial on a VNT Because they really don't waste the exhaust energy. This way the vanes aren't they only control for boost.

Sounds crazy, but i was wondering what it sounds like to you guys.

Like i said i think it would be easier to set this up on a injection pump test stand.

[foxracer1]

Yes as i think about it more it seems like it will be very difficult to tune.

I have never heard of a MBZ overboost control valve. Are there any places that still sell these?

I was also thinking you could put a rated spring set for the boost you wish in the LDA. I would be set so the height would be about the point where the ramp turns around. Therefore the LDA would function the same all the way to the max boost point, then it start to reduce fueling. Probably to complicated for the benefits.  Let me know what you guys think.

[pernalonga]

I don't  think that would work, because if the LDA goes beyond that point and actually starts to cut extra fuel,... it means it will stop sustain pressure in the manifold. So it will go back again to the point where it sends more fuel again....

I really think you should control LDA fuel delivery through the wastegate.

Get a pressure dial gauge, install it and play around with the wastegate actuator.

Regards

[foxracer1]

Well i can be sure how exactly it would operate untill i have BOOST for one and a means to test it.

I would think if you could tune it to do so it would find an equalybrium(sp?), that would idealy be some where in between the very top of the ramp on the pin and the point at which the pin starts to ramp back out. I understand how the wastegate works but it is just that "waste".

My theory is that the excess fuel will be cut out and just the fuel needed to sustain the boost desired. This would lower egts slightly and reduce fuel used at WOT. Obviously it is not such a big deal to conserve fuel at WOT. But I find it hard to drive "easy" so this would in turn help my fuel consumption.

[saurkraut]

I think without some sort of feed back loop (waste gate to LDA, almost impossible to conceptualize, let alone build) the waste gate and LDA will probably cycle opposite each other.

My early booste experiments:

I cranked my fuel, turned the pin, closed the waste gate, and screwed down the blow off valve.  I did not disable the blow off valve completely.

First run: booste built rather rapidly pas 15 PSI.  Above this point the booste cycled back and forth between 15 and 20 PSI in rappid succession.

I removed the spring in the blow off valve, dropped a short allen screw down the hole, replaced the adjustment screw, tightened it snug, and went for a test flight.

Boost snapped up to 24 PSI and stayed there.

Try your pin plan when you get it going and give us a report.

[foxracer1]

Try your pin plan when you get it going and give us a report.

I will though it will be awhile till i get my uncle to come off one or both of the TDs he has SITTING at his place doing nothing.

[RabbitJockey]

I think without some sort of feed back loop (waste gate to LDA, almost impossible to conceptualize, let alone build) the waste gate and LDA will probably cycle opposite each other.

My early booste experiments:

I cranked my fuel, turned the pin, closed the waste gate, and screwed down the blow off valve.  I did not disable the blow off valve completely.

First run: booste built rather rapidly pas 15 PSI.  Above this point the booste cycled back and forth between 15 and 20 PSI in rappid succession.

I removed the spring in the blow off valve, dropped a short allen screw down the hole, replaced the adjustment screw, tightened it snug, and went for a test flight.

Boost snapped up to 24 PSI and stayed there.

Try your pin plan when you get it going and give us a report.

haha thats how my jetta was setup for a while, loads of fun aye?