How much for a complete D-Jet system

Steve Arndt · Post by **Steve Arndt** » Wed May 15, 2002 1:17 pm

Maybe $250 if you find the right buyer.

bowlsby · Post by **bowlsby** » Wed May 15, 2002 3:16 pm

I have bought 3 or 4 2.0L complete D-Jet setups in the last few years and never paid more than $100-125. for the set. I've seen them advertised for more, but they don't seem to move. I will offer you $125 plus shipping if you part with it, and if its complete/functional as you say.

OTOH, Brad Anders' in depth research suggests that the stock D-Jet induction, properly tuned, should be capable of handling up to 2.4L engines, primarily if not solely with only recalibration of the MPS needed. If/when I need a rebuild on my 2.0L car, I would likely get the 2270 and at least attempt it. I think Brad and other 914 owners would be very interested to see an attempt to make it work, and document it, if you are willing.
http://members.rennlist.com/pbanders/

pbanders · Post by **pbanders** » Wed May 15, 2002 9:19 pm

Yes, the 2.0L D-Jet system should work up to 2.4L by adjustment of the MPS. But that's assuming you do not go to a non-stock cam with significant overlap, as the cam will produce lower idle vacuum and also change the shape of the volumetric efficiency curve. The stock curve is hardwired into the ECU and can be altered only through modification of the ECU speed control waveform generator circuits. If Jake's motor uses a non-stock cam, you're going to have some issues.

Personally, I'd go for the bigger displacement and higher compression, and keep the stock cam. It produces more low-end torque and makes more sense for street use.

Brad Anders

Brett Anderson · Post by **Brett Anderson** » Wed May 15, 2002 11:50 pm

After much deliberation, I am converting to the dark side by pulling a perfectly good working D-Jet system from my 914, 2.0. In a search for more power, I am building a 2270 and, from what I understand, the stock D-Jet would be inadequate.
I was planning to keep all of the parts to convert back to later, but I realize that that is very unlikely and I should just sell them.

Before I go and advertise it, how much do you all think a perfectly working 2.0 d-jet system(from the fuel pump, to the air box to injectors, everything) worth? If I can't get enough for it, then I'll keep it.

ray greenwood · Post by **ray greenwood** » Thu May 16, 2002 7:36 am

Brad, I concur with that. As much as I like my web #73, I have found that its significant overlap...and resulting loss of compression factor can make tuning a little more finicky. The spring modifications I have made to the pressure sensor have really helped to damp the resulting pulses...but thats probably more than most people would like to get into. It also further illustrates that a great deal is possible with just tuning the MPS. As long as the heads, intakes, TB and exhaust can flow enough...I see no reason what soever that D-jet cannot handle much larger engines. Its a matter of adjusting sensitivity of the MPS, correct ballasting on sensors...and increasing fuel pressure and volume to match. All simple....a little tedious in testing and tuning. The new cam for the trigger points has worked quite well (until I broke the cam last weekend. I have been meaning to get with a few other people...most notably Jake Raby, to get a better idea of what the static compression should be boosted to, to offset the loss by the overlap of the exhaust valve timing. Since I have changed the timing of the injections with a new distributor cam, having to use the stock timing of the #73 may have been negated. Maybe web cam produce a #73 with a split duration like the cam Jake likes to use...that will have less overlap? It will be worth asking about. Even correcting for compression losses, though..will only boost efficiency, and not correct the vacume signature problem coming from the overlap. Still a nice cam though.
A little note on a few things I had been working on as I drive to work each day. I have a spread sheet I have been making...using a digital barometer and my trusty sling psychrometer. I have noticed...that as the barometer rises and falls..a very slight difference in adjustment to the outer diaphram stop keeps the car running at a much smoother and consistant rate. The weather fluctuates like crazy here. Its a huge differnce. It makes sense, as differences in atmospheric pressure = differences in air density= differences in the vacume signature=differnces in the stroke of the diaphram. I am putting together a correlation chart with engine and ambient temp chart to find out what adjustment range works best at what inches of mercury on the barometer. Its never more than about 1/5 turn either way...but its significant in performance. I already have a small clamp on bracket built to either allow turning the screw with either a cable from the dash...or if I can find a small barometric solenoid or chamber I can attach to a slotted lever...I may make it self adjusting. When I get my engine back together and get a c couple more months on the engine and test grid...I'll drop it into the forum for consumption. Ray