Author Topic: Which injectors should I use? (Read 5017 times)

patracy · « **on:** November 23, 2007, 05:23:40 pm »

Short story:

New NA 1.6 Short block +1mm overbore
Turbo 1.6 head and turbo setup, with turbo IP.

Injectors to pick from:
1.5 set, 41K miles on them
1.6 NA, 114K miles on them

I also have a couple 1.6 TD injectors, but they need work, and another injector.

I also have a set of GM 6.2 injectors laying around as well. I thought I read that some people are using these?

The engine will be installed in my Suzuki Samurai. Not looking for a monster powerhouse. Just 70-80hp tops. (shade over TD power) Cooling will be oversized rad., external oil cooler, and intercooler. Also likely to be running coolant plumbing to the back to preheat a second fuel tank. So I'm trying to compensate for the lack of oil squirters.

blkboostedtruck · « **Reply #1 on:** November 23, 2007, 05:55:15 pm »

I say the 1.6TD ones and have new nozzels and poptested w/merc nozzels
DNOSD261 spray pattern is important! so since you have the TD pump use the 155 bar injectors! the nozzels are only like 40 bucks for 4 of them!
I put them in my TD motor and thier great! thier not that hard to rebuild i did mine my self but i did buy a poptester though!
thanks Duane

P.S. volkswaparts.com has 155bar injectors new for 24 bucks a piece!

dieselsnowmobile · « **Reply #2 on:** November 23, 2007, 06:37:49 pm »

You have put all of that money into the block, why not buy new injectors? Injectors life span is only 60,000 to 100,000 anyway. Save your new pistons and buy new injectors.

patracy · « **Reply #3 on:** November 24, 2007, 06:57:27 am »

Where can I find nozzles in the states? I emailed Jack at vwparts, and they only sell remain'ed ones for $50 each.

I'd like to build a pop tester as well, since this will be a normal maint. item.

patracy · « **Reply #4 on:** November 24, 2007, 07:10:28 am »

Or... can anyone here rebuild calibrate mine to 155 bar?

blkboostedtruck · « **Reply #5 on:** November 24, 2007, 07:38:06 am »

I can do it! how many 1.6TD injectors you have? I have 1 odd ball here i can sell you!
Duane

patracy · « **Reply #6 on:** November 24, 2007, 07:58:11 am »

Quote from: "blkboostedtruck"

I can do it! how many 1.6TD injectors you have? I have 1 odd ball here i can sell you!
Duane

Ooops, misread your post when I PM'ed you. I've got a set of NA injectors. But I need them rebuilt to TD specs. I've got three TD's laying around though I think.

Black Smokin' Diesel · « **Reply #7 on:** November 24, 2007, 12:51:19 pm »

IMO set the injectors at 130bar and time the pump to 1.05. That way you'll have less pumping losses from the IP with the same amount of power (meaning better MPG).

patracy · « **Reply #8 on:** November 24, 2007, 02:16:55 pm »

Ok I'm getting two answers here? Don't use them and use them with different timing?

Would there be any harm in giving the 135's a go at first? What exactly should the timing be set at?

blkboostedtruck · « **Reply #9 on:** November 24, 2007, 03:22:34 pm »

Andrew is pretty knowledgeable I take his advice all the time! you can set your pump at .95 or at 1.00 thats what i set mine at! .95 for n/a and 1.00 for TD really can't go wrong at that! safe setting for the I.P.!
thanks Duane

CoolAirVw · « **Reply #10 on:** November 24, 2007, 05:24:00 pm »

Andrew I assume you've used 135 bar injectors on some TD's to verify that they do work and last? Not to question your judgement at all, I just wanted to bring up a theoretical point.

I was just reading in the Bosch Diesel Disributor Fuel Injection Pump Technical Instruction manual (p. 48.) and I quote,

"And finally, the nozzle must be able to seal off the fuel injection system against the hot highly compressed gases from the combustion chamber (up to approx. 1000 degrees C). In order to avoid blow-back of these gases when the injection nozzle opens, the pressure in the nozzle's pressure chamber must always be higher than the combustion pressure. This requirement is particularly difficult to comply with the end of the injection process (when injection pressure has already dropped while combustion pressure is increasing rapidly), and it requires careful matching of the injection pump, the nozzle, and the pressure spring."

Point being a turbo motor's combustion pressure at 10 psi boost max throttle is going to be higher than a NA's combustion pressure at max throttle. That is the case isn't it??

Seems to me (in theory at least) that using lower bar injectors on a turbo would risk combustion pressure pushing into the injector nozzle. Now what problems could this cause??? Only thing I could think of would be coking of the nozzle and making it stick over time?

I have no practical experience here just raising the idea for discussion.

Black Smokin' Diesel · « **Reply #11 on:** November 25, 2007, 12:39:14 pm »

^^^ I'm running 130bar merc injectors with up to 23 psi of boost and it works great. But your concerns are normal. If I were to run more than 25psi of boost I would probably have the injectors rebuilt to 155bar.

135bar = 1958.00946psi and 155bar = 2248.08493psi. A healthy TD will have a cold compression of above 400psi but I don't know what kind of pressure there is inside the cylinders during combustion. Anyone have an idea?