Bleed Valve Installed on Line to Wastegate

[seanfournier]

the n75 valve which controls the wastegate acuator is a "frequency valve" by controling the OFF-ON-OFF frequency one can thus control boost levels and drop off.

With my device (optional touchscreen) one would be able to program boost limits, build-up, drop-off, etc. Every aspect of boost can be controlled. Its calibration will work of the MAP sensor which is a voltage reading. my device will also have a thermocouple, AFR, MAF inputs so that the with the combined information from all these devices proper fuel can be determined and thus adjusted by changing values from the MAF that are sent to ECU... eg. if the MAF is reading 100g/sec the value equivelant of 120g/sec can be sent to the ECU thus making the car run a little richer etc. I've yet to figure out ignition timing and wether I need to piss around with that.

The beauty of this project I hope to successfuly create... totally user configurable. Of course I can't say this is a 100% sound idea... but everything checks out so far... Its also not going to be cheap.

A PROPER turbo kit is one that doesn't cut corners. APR's kit is in my opinion an ALMOST perfect example. It lacks small things like ports on the downpipe, I don't like Inconel, I hate things that aren't configurable.

[Kor]

I think the reason no one has done what you are doing yet is they ask themselves - is it worth the money?

[QuA]

Kor how did you rip those n75 clamps off? TIGHT as a mofo.

QuA

[seanfournier]

is it worth the money??? good question...

I figure the device will be around $1000-$1500.

But it could eliminate:

Boost gauges and tapping into the manifold to get a reading...
Wide-Band O2 AFR kits and gauges...
Pyromters/EGT and gauges...
EEPROMS...
Possibly even Turbo Timers...

This is like a standalone engine management unit made simple. We'll see if I can even make it work

[Kor]

I cut the clamps. Use sharp cutters.

[1.8Trip]

Hey Kor, is this something similar to what you are doing?

http://www.izvw.com/overboost.html

[QuA]

I cant wait till my damn n75 comes in from Northland.

[Kor]

Neil: Yes that is similar to what I am working on right now.

The idea is to use a relief valve (MBC) to bypass the N75 at a specific pressure to avoid spiking. I beleive that when your boost spikes up to 20psi then drops to 15psi this is actually not making your car any faster.

However, I have tried it and it doesn't work as-is like in the link you posted. The problem is that with the bypass your wastegate is getting even more pressure (my wastegate is already getting too much pressure due to my high flow exhaust). The result is that the wastegate opens very far and very rapidly, causing boost to drop too fast.

My own design was just like this except I also had a bleed valve before the wastegate, to bleed off excess pressure. However, the bleed valve Forge sold me melted. I am trying to find a brass needle valve. Home Depot has some however they use compression fittings and I need hose barbs. Argh!

All of this is just fine for a prototype. However, in the long run I would like to toss the N75 completely. If I use a regulator before the wastegate, and if the regulator is precise enough, I think I can do away with the N75. The car may drive a bit different but I think this is something that I can just get used to. This has been done on an audi TT and the person who did it reported an actual gain of about 15%.