GPF

Ah, OK.

On mine fqs0 is minimum fuelling, fqs1 is +3%, fqs2 is +6% and fqs3 is +9%. (The next 4 mirror this but with 2% ign retard.)

I guess we're saying the same thing then!

I've already tried running 4bar instead of 3, and setting Master AFM to -15% but that wasn't enough to get round it. I'm going to try the fqs route next - probably next weekend.

Have you already done this and found it worked?

Regards

Graham

'88 Turbo S

jimbo1111

Have you already done this and found it worked?

I have maf. It doesn't matter. It works with both map or maf.

Mike S

Hmm....I've got Danno's chips and running the AFMLink MAP kit I was running 19.3 psi on Saturday as verified by the dyno. No overboost cutoff on my car. Is it exactly at 20psi that this occurs?

david benjamin

"Conversely, does anyone have this problem but does not have the MAP conversion?"

No MAP, Guru V9 chips, and major cut out (usually ~4,000 rpm) when pressing down the carpet, in 4th or 5th gear up a hill. Most of the time my 951 behaves itself. But once it has cut out, it cuts out again and again, and under less demanding conditions than before it cut out in the first place. But if I drive with the engine lightly loaded for a few miles, it's back to the beginning.

We really must get to the bottom of this !!!
David Benjamin

Duke

this was an easy fix...

My Link Tuning Module has been broken for long so I didn't have one available during my last session with the cut off (as dicussed on former page).

Well, I got a new tuning module yesterday and before we went out for a test session I scrolled through the menus and saw that the Vmax clamp was set to 5.0 volt. Reduced the number to 4.62, saved the data and went out for a test drive and everything was honky dory

Didn't have the chance to try out boost above 1.4 bar/20 psi but more of that to come within a week

GPF

Hi Duke,

I would be very careful with this approach.

Surely this could potentially result in you running dangerously lean at high rpm & boost levels? What you have done is to restrict the Link's ability to pass the true air flow data to the dme, and so restricted the amount of fuelling above that point. In effect you have manually maxed out the MAP sensor.

I presume you have wideband so you can monitor this?

Also, I think that the overboost cutout problem can occur with lower voltages further down the rev range, so just clipping the max voltage will not necessarily prevent the overboost cut out at say 4000 rpm in 4th/5th under full load?

Just trying to help.

Regards

Graham

'88 Turbo S

Duke

Thanks Graham,
but no worries everything is under control. The max voltage is set so that it never goes above 4.7 volt which triggers the cut off. The DME still reads from the WOT map and Link still reads from its cells.
I understand your theoretical concern but in reality when datalogging you realise that at WOT above 5000 rpm the output votlage from Link hardly varies at all regardless of boost levels between 1-1.4 bar.

pete95zhn

Reading this thread from beginning raised some questions...please give me some VERY simple answers...

But before the questions some background.
Current set-up:
-Guru V7 (or V8) chipset
-Guru MAP-kit, ie. AFMLink
-KKK27/6 hybrid with 60mm turbine wheel
-Siemens 72lbs/hr injectors
-stock snorkel and airbox
-3" exhaust all the way from turbo

Problems started after changing the turbo and injectors,with stock turbo and injectors a/f adjustment at dyno was easy ( 278hp/5500rpm @flywheel /1,2bar-12,5 to 13,5 a/fr).
At last dyno after changes run mixture stayed at 14,75 no matter what done.Produced only 330hp/6000rpm @flywheel /1,0 bar.We didn't dare to try higher boost.FQS at DME was set to match injectors and almost all fuel delivery problems are counted out.
During our trip to Germany I encountered problems with WOT acceleration at 4th/5th gear...all OK until 5000 rpm,boost as set ( 1,0 bar ) and narrowband not below stoichiometric ( best it could do... ),but after 5000 boost started to rise with rpm and at 6000 there was 1,3bar.At first good pull I didn't notice this boost rise ( there was some traffic to observe with speed above 200km/h ) and the ignition cut-out scared the hell out of me,it felt like something grabbed and held the car.Well,I thought that mixture went lean,it started to knock and KLR did what it's meant to do.Then I started to observe gauges and noticed this boost rise.After reading this thread it seems that this overboost protection caused ignition cut-out.
BTW, partial-throttle acceleration goes well,I managed to get 280 km/h to the tach at 6400rpm and 0,6 bar boost. It's just long duration WOT,dyno pulls doesn't last that long either.
I just checked my AFMLink settings and loggings with SerialLink.Max gain is set to 5,00V.What puzzles me is that at loggings Vecu shows 52 at idle,and 255 at WOT when boost exceeds 0,9 bar ( 0,9 - 1,1 bar ) ,independent of rpm ( eg. 4700-5700 rpm ).

To questions:
1) Should this Vecu be multiplied with something ( like 2,0 ) to get actual voltage that is inputted to the DME ? ...and DMELink gets 1,04V at idle, 5,00V at max.
2) Or is there something wrong with my AFMLink and maximum voltage DME gets is 2,55?
3) Do I gain something from playing with this max clamp voltage,even if I'm not going to use more boost than 1,2 bar.
4) Has this lean mixture at dyno something to do with voltage AFMLink sends to the DME.
5) Should I try with different FQS settings? After first start with new gadgets my car run with overly lean mixture,I had to add about 30% more to get it running smoothly,even though FQS was set to larger injectors,this with idle...
6)Overboosting (unwanted boost rise)....bad wastegate or something else?

Duke

Pete I will send you a PM, but in short: turn your FQS one click counter clockwise, set max clamp to something around 4,7 and then go for a spin (preferably with a wideband!)

Duke

Perhaps I should add a reply regarding your voltage. Divide the number (255) with 51 and you get the actual voltage = 5 volt at WOT. That answers Q 1,2,4.

Bill

I have:

Stock hot side, Garrett dual BB TO4e
Guru 65 lb injectors
Guru chip programed via wide band to my engine
MAF through stock air box and snorkel
ARC II piggyback controller
3 bar pressure regulator and Lindsey high volume bosch fuel pump
3" down pipe through cat
Stock ignition, bosch plugs, stock heat range

I have my EBC set to 22 psi. At last weeks Devek dyno day, I recorded a boost spike of 23.7 at 4,000 rpm. My car runs flawless and pulls smoothly through redline. No bucking, no cut off.

My only issue that I am working on, is that I am going lean at 3,000 rpm. This has resulted in high EGT's which are causing NOX and a failed smog test. With the ARC II, I do not have fine enough control to tune out the lean spot at 3,000 rpm. But these are the fun challanges that come with modifications.

pete95zhn

Thanks,PM's noticed.

TurboTim

On Project 951,we reached the limits of the Link AFM at 17.5 psi.We talked with Neil at PD and he said that is about all you are going to get out of it.

NZ951

Doesnt it have a 2.5 bar MAP sensor like the LEM V5 (opposed to the 3 bar in the Link PLus)

Mike S

17.5? I've got dyno results from two weeks ago that show 19.7psi and a 12:1 air/fuel ratio up to redline. What was the limit at 17.5psi?