Usually when you start to get crazy high spikes like that its a bpc issue. My 9k did that last year....it got to the point where it'd peg a 30# gauge w/o any problem.

I'd try swapping in a known good one or try cleaning the one on your car.

 

yeah the ecu should not let you boost till fuel cut

I also wouldn't add injectors without a re-tune to match, that is not gonna work so nice. maybe even cause damage.

I would also try a bpc.

 

fix the problem first then modify

 

That's not the way Aaron rolls ;-)

 

If there is a problem, fix it by modifying!

If you need to replace a part, why not replace it with an upgrade... makes more sense that way. That way as you repair your car, by the time it's running the way it should be, it will be beastly

 

Yeah, but you're talking about replacing a part that is not the problem to fix a problem with a different part.

Changing the injectors will not solve the issue that you are having, in fact it will cause more problems because your car is tuned to run only the injectors that it already has.

I seriously hope you're just kidding around with that idea!

 

When you alter boost controllers environment (IC, piping, turbo etc) you should see out that the controller keeps up with the changes. To some changes it will adjust (T7 is better in PID self tuning compared to T5) and to it wont.

In the SW there is a set of maps where the PID tuned and it is recommended that they're tuned properly for the cars HW. Some tuners know how PID control loops work and know the meaning of P (power) I (integration) D (derivate) and their affect to outcome (boost curve) when changed, while other are out of the issue just like the string on tampax Meaning they poke parameters without understanding what they're actually doing...

 

The fuel cuttof was kind of a 1 time fluke. And Jessop, the injectors comment was more of a joke, because bigger injectors means bigger turbo means bigger FPR means new tune. And all that means my wallet will divorce me and move to Alaska.


It was a 5th gear pull around 90mph downhill into a cool valley heading towards lake superior. Sudden 4-5 degree temperature drop in the valley. My guess is the sudden cool rapidly condensed the air already in the intercooler causing a spike.


Hmm.. thinking on that last paragraph, that doesn't really make sense, but yet it does?

 

Its easy, if you are hitting fuel cut and want the boost to NOT spike as high, just lower your base-boost a hair and it will not spike as high. If you want it to spike higher, raise your base boost a hair...

John

 

Amish, what s/w are you running again?

 

I'm running a secondhand, custom tuned, Stage3+ Nordic ECU. The ECU is one of 2 that were tuned by Magnus for Dan & Ced (Snow4_1Man & Blaque_out). Supposedly they were the first Nordic ECU's in the US. Dan sold it to GildedSplinters, who then Sold it to me. Both cars that had this ECU met their demise in accidents IIRC. I'm hoping to break the stigma.

The tune accounts for 3" Downpipe + exhaust, Larger than Viggen Intercooler, and a Stage 3 wastegate helper spring.

I have the downpipe & larger intercooler so far. Still on the fence as to whether i should install the helper spring, as Nick T assures me I'm boosting good enough without it.

I haven't been able to duplicate the fuel cutoff since, so I'm guessing it was s fluke spike due to conditions.

 

The cut on that software (same as mine) is 23lbs. Like John said.. lower your base boost slightly, cause that cutout isn't going anywhere. Be grateful it's there

 

Yeah, but the APC/BPC shouldn't let me spike that high, should it?

 

it does what the software lets it/tells it is OK
but it can't always catch spikes quick enough, that's why you have fuel cut and other safety

 

When i had Jak's stage 3, I pulled off the W hose to the wastegate off my BPC and was unable to hit fuel cutoff...

 

No fuel cutoff = JSP Kaboom

 

Boost can always spike especially if there is some fluke with the BPC valve...like if it got a little stuck and then started working again.

 

^ fuel cutoff is actually something that can cause the kaboom! When the fuel is cut you risk getting a very lean condition....which could cause a kaboom. Spark cut would probably be a safer way to handle things.

 

If there is no fuel (fuel cut off), there will be nothing in the combustion chamber what could ignite... remember the injector gives fuel for one commustion, so there is no transition time where you could have some half filled cylinders, which would then run lean.

Spark cut of with fuel not cut puts the gas in the manifold and to have it pop there is something to remoned, same applies to limiters which delay timing like crazy.