Edman951

Hey Guys,
I was doing little test & tune drive with my new custom chip from Danno. And after tuning it up to 20psi. I turn up the boost just a hint more to see. And at about 21 or 22 psi on my autometer gauge. Under WOT the car just jerked hard. Kinda like i hit fuel cut.
It made me think that the map sensor in the Link box may have a limit.

Does anybody know if their is a limit on the map sensor?
Is the sensor a 2bar? 2.5bar?

Danno if you read this.
New custom chip work great. It very smouth and drive nice with my new turbo. I still need to tune it a bit in some spots since i have a different turbo then what you have setup for.

Also i think i will need bigger injector. Probably some 75/lb, because i think i am pushing the 55's to the limit.

mark944turbo

Are you sure you are pushing the limit of the 55s? I think they are good for more than that. Danno told me that it was a 2.5 bar sensor, and that the link box was good for 25+ psi. I think Laust Pederson was running that much on the link stuff, or maybe he has huntley stuff i forget. You are probably hitting different zones that you have not tuned. Search for a thread started by me (mark944turbo) lately, I asked the same question. Look at the zn screen and your tech edge display when it happens and see if it gets lean, like 15 or 16 to one would cause the cut feeling.

That same thing is happening to me by the way, but I havent gotten around to making those fuel changes that danno recommended.

m42racer

The Link onboard MAP sensor is good for 22 PSI max with some tolerance either way. Thats what I was told.

Duke

But even if you maxed out the sensor's range one thinks it would continue to read from the last row in the fuel map?

The Link box should not cut the fuel under those circumstances and act like an overboost protection. So it seems to me you hit the chip's overboost protection. I suppose most tuners just raise the overboost protection limit and perhaps Danno set that to around 1,5 bar/22 psi in those chips.

Danno

Yeah MAP-sensor itself may only go up to 22psi, but all boost levels above that will end up traversing the highest load row on the 3D map. Actually the 3 highest load rows on the MAP-computer's 3D map correspond to 9, 16, 22psi on the high edge. But all three of these rows fall onto the underlying chip's WOT map. So you can have a custom adjustment for 9psi, 16psi and 22psi. This last row can then have an adjustment for any max boost you want. Just that it won't be optimum for something in between, such as 20psi if you've got it programmed for 25psi.

I suspect that I may have to raise the overboost-protection limit. There's some room to raise it a little more...

Another area that some people have experienced is ignition related. Narrowing down the plug-gap to about 0.025", adding a coil-condensor for a little more spark, and programming in more charging time for the coil seems to help.

J Chen

Hi Edman,
Hows the going ? Hey, glad to hear that your new chips
are working out nicely. I'm awaiting my custom chips
from Danno too. Lets hope it'll turn out to be as good as
yours.

mwc951

I am waiting for 75lb chips.

chris951

I"m only running 16psi in 4th gear, can I shim the wastegate more than 3mm?

Edman951

Danno, What is the boost limit in the chip?
I must of hit the limit because my a/f was at 11.5 or so on my WB when it jerked.
I was also maybe runing more then 22psi. My autometer gauge could be off a few psi. Evendo it brand new.

Could hard detonation case a big jerk / stop?
When i hit it, It felt like the car stopped moving. It was not just a lost in power, it was like if i let go of the gas completlly.

Hi JChen, I'm doing good. And you? Did you get a chance to go on the dyno. Or take picutres of your setup completed.
I really want to see it.

Me i didn't get much time to play on my car in the past 2 mounth.
I just finished moving my compagny (20000sqft warehouse) and i moved in to my new house all in october.
But now the car pull strong at 20psi.
I really got to make it to the dyno before the snow comes.

Edman951

Mark,
I can't say for sure that i'm at the limit of the 55/lb injectors.
But i think i will be soon. I'd have to check how much they are running at.

And i don't think my fuelcut was zone related. Since the top 900-965 are the zone i tuned first.

I will try it again with more fuel and i'll tell you what happend later.

Edman951

OK so i went for another test drive.
I hit a fuel cut went i see more the 20psi on my gauge.
I did a test, i tuned my boost controller to fluctuate a bit using the balance button on my profec B. On WOT at 19-20 psi its cool. But over 20 i hit fuel cut.
Very bizare.

Also i am now conviced i need bigger injector.
When running 18-20 psi from 5500-6250(revlimit) the car lean out from 12.2 to 13. I added 15% fuel up top and it did nothing to rich up those zone.
That mean i must be at 100% duty cycle right?

Also the rev limiter is too low. I keep hitting it since the car pull very strong at those rpm.
Danno, you are going to have to make me a new chip for 75/lb injectors and 7000 rev limiter.

mark944turbo

Damn, looks like I will be needing some 75lb injectors as well.

Alpine951

Danno Wrote:

"I suspect that I may have to raise the overboost-protection limit. There's some room to raise it a little more..."


Yes, yes, please Danno raise it some more. Its a really sad situation, this boost stuff. Just can't get enough! Next year its the map for me!

Dark Lightning

Why not just eliminate the overboost protection all-together?

badcoupe

I hit my fuel cutoff at exactly 20 psi every time. Msd better coil more fuel etc 20 lbs on the dot everytime my car cuts out, it ticks me off big time as it's hard run exactly the right amount all the time in all the different gears maybe I need a EBC now. I still want to find a way to get more boost though.