Didn't know people were still using these devices... Wouldn't a 3bar MAP be a better option for raising boost cut? That combined with 550cc injectors and you almost don't need a SAFC.

 

when I put a 3 bar on there I could not get the car to start even. the voltage is much lower but if someone figures out a way let me know
also a 3 bar messes up the whole range of values, whereas these boost clamp devices let the ecu see the perfect value until you reach boost cut, and from there its easy to just go up injector sizes to be safe for max boost and use a simple afc to trim out some fuel for regular driving if the o2 sensor doesn't do it enough. I seem to have enough fuel though, I just can't make it past boost cut yet to see how much more.

 

Couple it with 550cc injectors and watch it run
You're right it does screw with voltage that the ECU sees. Would also need a SAFC to make it run.
However, the difference in voltage the MAP sees is percentage wise offset by 550cc injectors. It's possible to swap both and be almost perfect even without SAFC in theory. (This is all assuming you went from a 2.3bar to 3bar and from 370cc to 550cc)

 

yeah thats what I thought some of those theories were partly mine and I still never got it to work with the 3 bar.
I would be surprised if it fires up with 550's and a 3 bar without a whole lot of safc fudging. more likely to be able to use the motorolla 2.5 bar map sensor but I couldn't get it to start up on that one either.

 

Ishootstuff, can you verify the final wiring of the unit, and more specifically, the vref lead? Mine is not behaving as expected...

Thanks!

Edit, it appears that vref needs 5v now that I look at it again. Maybe that was my problem. I gave it 12v.

 

Vref is +5v pin B41 should be a blue/red wire.

 

anyone care to double check the layout? got bored and put it into a file so one could order the board with the traces already layed out and simply pop in the pieces and easily solder them on. no getting wires wrong or coming loose int he future.

might notice I also threw in a speed cut circuit in there on the right side operated by a 4 pin switch (turn on or off or just jumper to always on) which are powered by the same power wires and ground as the main circuit, so its a 2 in 1 function where you could flip on or off the speed cut, or just leave it on with a manual transmission. basically it cuts the speed signal in half, so you can go double the limiter. not sure how this affects auto's hence the switch one could wire in or just jumper if manual, or leave disconnected if you don't want the speed cut circuit.
Once I confirm it works I'll post up the cad file for those who want to order some.

 

That looks super cool! I have no interest in a speed limit defeat. 155 was fast enough for me - of course that was the NA ECU and a Neo. I'd love to have a RPM limiter defeat though. Hell, while I'm wishing, I want to mod my Prius to give full gas engine and electric output instantly instead of the soft weak curve it has now.

 

Lol, that is pretty funny about the prius. still probably wouldn't be that quick feeling.

That is why I left it on the right side with a switch so if you don't install the speed cut components the boost cut will still work just fine.

The speed cut circuit on the right is just a divider circuit. there are even pins for dividing by 1/4 and 1/8 etc.. right now it is wired for 1/2 if I remember right.
Rpm limiter can't say I know how to do that one.. well at least not yet haven't looked into it.

Yeah the stock 155mph is fine for most, but the problem is when using the JDM ecu in our cars because of the mph kph speed difference it works out to about 110mph speed cut, which if you are trying to do a quarter mile run at the track you can easily hit it and can even be dangerous if you are not aware of it cause it cuts out instantly and often times you are boosting as well.

I will test the prototype one I made off the diagram with just regular wires and a protoboard, if that works I will assume the layout is good and order a few and try them out.

 

This is sweet! Great to know for you GTE ecu equipped cars. Now you can throw a bit more boost without worrying about Fuel cut.

 

Ali did you get that circuit built and tested? I love the combined circuit layout! I build my own guitar effect pedals and this is right up my alley. Looks like I need to brush off my pcb etching stuff again!

 

I came very close, so now I'm interested

 

haha, yeah eventually you hit it and it comes out of nowhere, almost dangerous at times.

I haven't had them manufactured or anything yet, I actually forgot about it. I have the schematic though on my computer if someone wants to get some made or maybe I can do a batch and sell the extras.

I had built out the boost cut just on a prototype board but haven't put it in the car yet. once I do that I should know that the PCB design will work then and get them made. the speed cut I am fairly certain that will work its pretty hard to mess up a divider circuit. when I get my car up and running I will go ahead and test the one I have built by hand.

Killersqrl if you want the pcb file PM me your email and I will send it to you if you want to mess around with it. I did it in Express PCB which is a free download and then they make it and send you the boards.

 

Awesome, I'll pm ya. If I can get a clean circuit template I can print it out on a laser printer and iron it onto some blank copper pcbs I have, then etch it.

 

once I figure out where I saved it I will send it over.