Which system is best?

mrbaja · Post by **mrbaja** » Thu Mar 21, 2002 7:48 pm

Aloha gang,
I'm slowly building a T4 for my street/offroad baja. I have 3 options so far for complete F.I. systems:
1) K (KE?)from '86 4000s Audi
2) D (digifant) from a '93 Fox
3) L from a '75 bus

Of course I want 1,000 HP and torque at idle with 100 mpg out of this! Yes I'm kidding. Plans so far are 96mm pistons, 66 or 71 mm stroke, 1.8 heads with valves cut to 2.0 914 specs. Not sure of cam or compression yet. Small turbo for high altitude is in future plans.

Which one would be my best direction to go? Of course this is a low/no budget plan.

Aloha, Theo

ray greenwood · Post by **ray greenwood** » Fri Mar 22, 2002 6:43 pm

The L-jet has the most going for it out of the box...for the engine you plan...it can be uptuned a modest amount with no real problem. The K-jet has a bit more to work out, but I think it has the most choices for mix and match for parts until you get what you want. The digifant...is a good system...but extremely hard to re-pattern to a different engine seeing as how the fuel and advance curves are set by one ECU. I would go Motronic before I went digifant...both both of those are dim choices for your application in my opinion. Ray

mrbaja · Post by **mrbaja** » Sun Mar 24, 2002 7:43 pm

Mahalo Ray! I think I'll do the K jet since it has the O2 sensor. I was thinking of the possabilities of using the air flow meter and throttle body and injectors of the Digifant with the L jet ECU but from what I've been reading it looks like a big no no to mix and match parts. Besides I'm not hard core enough to play modification games yet. I'll start by transfering the CIS from the Audi to the T4 as a complete unit, get it dialed in then go from there. Not a true KISS way to go but somewhere in the middle I think. :cool
Aloha, Theo

[This message has been edited by mrbaja (edited 03-24-2002).]

ray greenwood · Post by **ray greenwood** » Mon Mar 25, 2002 5:39 pm

I have worked with K-jet for a long time...but never on a type four. Check some of the back posts for Evil ED....he does these. Some things to be thoughtful about. When taking parts from a K-jet car...make note of the donor engines displacement, compression, how long the manifold runners are...diameter of them,where all the vacume lines are hooked...even cam information can help. Make note of how far from the main manifold plenum the throttle body was...wether it had to turn any corners..etc. This way you can get a feel for how the system as it was ...was calibrated to run well. You will probably have to make some compromises while squeezing manifold under your hood...and all of that info may help to make decisions...and get you closer to proper tune...with less trial and error. Count on this...what was in the fuel loop should stay in the fuel loop if you want that set of fuel distributors and injectors to work as designed...ie: if there is a regulator, fuel accumulator, control pressure regulator, cold start switch...use them. You can always remove them if they become unnecsessary...or simply change them to a different part number and spec. if they need a variation. Ray