Turbo BS Thread

This is what they are here, 325cc:


Some other rz injector sizing you may be interested in:
http://www.2rzturbo.net/?p=82

 

Ok I'm definitely interested let me know when your ready to sell

 

Here's a pic of my set up any comments are welcome just be nice

 

I would say, recirc air should be reintroduced before the MAF to allow the computer to see a flow still.

 

You don't want the ECU to see any flow. You want it setup so that when air stops flowing through the TB, it stops flowing for the MAF as well. From that setup, it should be ok but obviously not. I think if you tighten up the BOV so it doesn't vent so hard and thoroughly, it should help.

 

It's not going to see full flow, but some air will be pulled through. Sounds like the ECU is cutting too much fuel. More flow, more fuel, no dying?

If we were dealing with a standalone ECU I would recommend what you are saying but we are trying to fool a stock ECU here...

 

Aight

Recommended intercoolers and.............



GO

 

Yes

 

Holy shit that was fast

I'll look them up, is that a capital y?

 

Not exactly. Actually a bit of the opposite.

The issue is when the TB suddenly closes there is still charged air in the intake pipes and that will have to go somewhere. The engine is not getting any more air beyond the idle control valve air but the flow of that charged air, be it out of the turbo or out of the BOV causes flow over the MAF causing the ECU to think there is air still going to the engine. It continues to add fuel and it goes so rich, it stalls.

We need to minimize the additional air flow over the MAF. The closer it is to the TB, the less amount of air there is in volume to flow over the MAF.

I think there are two ways to fix it. Either take off the recirc valve because what is effectively happening is the BOV is venting the charged air out past the Turbo but it still needs to flow somewhere. As it flows over your MAF, its causing the extra fueling.

or

Move the recirc valve further down stream of the MAF so that the vented air doesn't flow past the MAF.

Either way, you still need to make sure the BOV is tuned to not vent so suddenly. If it blows out the boost too quickly, it can cause a vacuum in the charge pipes which will suck air past the MAF.

Clear as mud?

 

So I probably need to order a stronger spring for the bov or go atmosphere?

 

I wonder if he had this same trouble but I thought this setup was to prevent stalling when you use MAF

 

Both.

There should be an adjustment screw to adjust the spring pressure

I would go atmosphere unless you can swap where it dumps and the MAF position.

 

The only reason I did recirculating was because I thought that was the way you had to do it if your using MAF as opposed to MAP to prevent stalling

 

It has to be done right.

How you have it setup, you are making things worse. The best setup would be if you swaped the MAF and recirc dump positions so it dumped on the other side of the MAF. You still need to make sure the BOV isn't discharging too quickly with a stiffer spring.

If you can't do that, vent it to atmosphere and that should be ok, but you still need to make sure the BOV isn't discharging to hard, otherwise, when it opens and vents all the boost, it may create a vacuum in the charge pipes that will suck air back through the MAF.

 

Ok I'll start by getting the stiffer spring

 

This is what I was suggesting from the begining?

 

I don't think so. You wanted more flow on the MAF . As it currently sits, all the charged air is recirculated to the wrong side of the MAF causing it all to back flow over the MAF. Not only can you not get more flow over the MAF than how it is currently setup, that extra flow is the problem to begin with. When the MAF has that much air flowing over it but the TB is shut, the ECU goes way rich and the engine stalls.

You want to make it so when the TB shuts, the air flow at the MAF stops just as suddenly. It pretty much can't be done but it can be minimized.

The opportune thing to do is get a computer and a MAP sensor as MAPs are much better than MAF's with charged air. And/or a computer that is smart enough to monitor the TB position sensor understand when to ignore the MAF voltage. There is only so much yo can do to fool a stock ECU.

 

Yes he originally had it atmospherically vented but had stalling issues of course. So he added the tial recirc kit and that fixed it for him. I pm'd with him a bit when I was putting my set up together. That was one of the reasons I went blow through. I know that tough to fit a MAF in the short charge pipe, though when non intercooled

 

Well, considering I was the one who stated it, I can tell you thats what I was recommending. Whether or not my synopsis was correct on WHY, I had the placement of the components correct, per your response here: