ShopTalk Forums | Aircooled VW Tech & Restoration Help

I'm looking for a way to modify the rev.limit for the Digijet (2,1 DJ engine).Making it rev higher
This is in the Digijet ECU and gets signals from the ignition.
Does anyone know if this is a separate circuit that can be modifyed or if it's in the ECU's EEPROM program.
I have read the EEPROM , but can't figure the hex files.....
Anyone have schematics for the Digijet ECU or links to where i can find it??

BOOM

and that is??

Engle 130 cam makes it wanna rev higher.

Thats why I' have made a Megasquirt for my wbx oval!!


Jesper

Ask John at aircooled.net if his chip raises the rev limit...

I'm waiting on UMS. I want closed loop PPP/ion sense, and intend to help get the latter working once the main "box" is working.

Still waiting for something from Delphi as to the coil-on-plug modules.

did you check the rotor in your distributor , it may have a rev limiter , I am not sure about the digijet but the L-Jetronic (early version of the digijet) did not have a rev limiting function in the ECU. Both systems dont control ignition , may be digijet limits high rev. by cutting of the fuel.
Eren

Something happens at 5500 RPM ; it sounds like fuel cut,yes.
ANd it does it in my other WBX car's as well , so a kind of rev limit is for sure.it says so in the VAG repair book also.
The rotor does not have a rev.limiter.

I have also looked at the Megasquirt , but want to check if there was a way to use the stock Digijet.It works OK otherwise
I'll send john a mail!


Thanx guys!

Unless you have modified your WBX heads, I hear you will start floating valves about the same rpm.

That will be the real limiter.

I'll have to test that
Well the WBX has dual valve springs.
Som says the will work fine in the higher RPM's

Time will show.

and some people say (type4.org) that VW hydraulic lifters don't work well over 5000 rpm , this may cause smt. like valve floating .

PS:DJ engine has hydraulic lifters

Eren

The DJ engine has Hydraulic lifters standard , yes , but will be replaced by
the older NON-hydraulic Type 4 lifters , also because of the Engle 130 cam replacement.

I have no experience with these hydraulics at high RPMs, but I if you do a bit of searching, someone who has built a few HiPo wassers says the heads have issues... with the springs specifically.

Perhaps I was thinking of a more radical application.

I do know the max lift is somewhat limited: A stock cam and 1.4 rockers works, as long as you stay under whatever that works out to lift wise, you should be OK.

fastback,

Have you found out that If the digijet really cuts-off the fuel at 5500rpm , or is it for some other reason , did you try the wbx with solid lifters w130 cam and digijet ?
I am interested because I have a complete digijet from a wbx engine and planing to use it one day on my 1776 type1 engine . my engine would rev to 6300rpm with carbs , If digijet would limit it , project would be a failure ?

mechano.
I have not assembled the engine yet (i'm in the middle of a Turbo WBX project, so it's on HOLD).But i know it is a rev. limit with the digijet.
With carbs though...
A friend had a 2,1 wbx with dual idf carbs and went higher than 5500 rpm.

Aircooled.net offers a Chip that fit's the 025 906 022D ECU (which i asume is the DIGIFANT ECU??) that increases the rev. limit to 6500 + offers more power.



http://www.aircooled.net/new-bin/viewpr ... d2=fsi0009



But does it offer more power compared to the DIGIJET 025 906 021F ECU...?? THen if a Lamda i fitted you can use the DIGIFANT & the chip to get more HP and RPM....i'm considering this DIGIFANT + Aircoole.net chip ECU for my Turboproject

I have heard that it is possible to change the Crystal that controls the CPU frequency .
Some one said to me that incresing the crystal by 10% it would also rise the Revlimit 10%