98 TDI excessive smoke

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
It’s the first thread in this section
Not much. But its imo not worth doing unless you smashing past 250hp. I hit 230hp at the rear wheels on stock internals cam and IP at 32 psi. With lots of fuel.
 

krook

Active member
Joined
Jan 13, 2021
Location
Hungary, Europe
TDI
AFN
i get that the 10mm pump can push a lot of fuel, however the larges the nozzles, the worse the atomization leading to too much smoke. the 11mm pump can push the same amount of fuel through smaller nozzles. plus the advance mechanism on the 11mm pump is superior to the one found on the 10mm one.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
i get that the 10mm pump can push a lot of fuel, however the larges the nozzles, the worse the atomization leading to too much smoke. the 11mm pump can push the same amount of fuel through smaller nozzles. plus the advance mechanism on the 11mm pump is superior to the one found on the 10mm one.
Incorrect.
Larger nozzles do not operate at a lower pressure. They operate at the pressure that the tunner pop tested and tuned them at. Do you have any idea how much fuel goes back to the tank though the return out of each injector is... and even so at WOT? It's a lot. There is always an excess of fuel at all demand ranges reguardless of nozzle size. This is not just for overkill but to also cool them and the pump.
It's a fact you can get better mpg even with big stage 2 tuned 764s because they have a better newer tech spray pattern and higher pressure (pop testing tune) and better atomization.
I dont know who told you or where you got that its worse... lol
Bigger nozzles dont just add more fuel.. they do it better.
There is nothing superior 10 or 11. The 11 just can delever more fuel over a higher rpm range. It's the size of the head that is more fuel but the 11 body has a higher cam lobe so slightly higher rpms get the fuel.
 
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Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
I may add that it's not the nozzle that adds the fuel more. It's the tune.
The smoke is from a lack of adequate air (boost to support the added fuel.
Not the nozzle.
 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
It's a fact you can get better mpg even with big stage 2 tuned 764s because they have a better newer tech spray pattern and higher pressure (pop testing tune) and better atomization.
Kind of kicking myself for not doing more thorough research. The guy at Kerma recommended the 1019s for me, but the 764s are probably what I actually wanted in the long run. Oh well. I guess when I do bigger power mods I might get them. The 1019 can flow up to 190hp which I'm pretty sure I'm not getting yet.

And then there's the 520s https://kermatdi.com/i-950-bosio-dl...html#!model=JETTA||make=VOLKSWAGEN||year=1998

Can't imagine what one would have to do run these.
 
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alanack

Member
Joined
May 10, 2022
Location
Rhode Island
TDI
1998 Jetta
Car is running much better now and my fuel economy is consistently 52-55MPG where before it was 41-48 and occasionally above 50.

Still blows heavy smoke if you romp on it.. i was thinking its got nozzles?

My core injectors on my bench need to be rebuilt.... what do you guys from Kerma??? I was looking to doing a hotswap. I drive 55 in the right lane like a turtle, not looking for any power? Stock nozzles best?
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
the point was that even the big 764's can be more eficent than the old oems..... any nozzle upgrade techincally is going to make more power but at the reason of eficency, the #1 best way to get more power is burn more of the fuel you are injecting. new nozzles do a better job of that... vs the older tech the car came with.
 

alanack

Member
Joined
May 10, 2022
Location
Rhode Island
TDI
1998 Jetta
Well for stock turbo, timing, and tune? The car has low miles ~160k but it sat a lot, and it was definitely beat on a bit... i think fresh injectors with the correct pop pressure would help a bit here.

I just hate black smoke, and diesels get enough bad rap these days especially volkswagens...
 

krook

Active member
Joined
Jan 13, 2021
Location
Hungary, Europe
TDI
AFN
i'm not sure how nozzles can be "ole tech". They are just a piece of metal with holes and a needle in them, no?
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
11mm makes higher pressure = more fuel, and also better atomization for larger injectors. tuning (timing, boost etc) is key and it's no problem to get excellent mpg with whatevr turbo you want and 11mm + reasonably big injectors (say up to .260s)
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
I may add that it's not the nozzle that adds the fuel more. It's the tune.
The smoke is from a lack of adequate air (boost to support the added fuel.
Not the nozzle.
the smoke can be many things. timing in the tune needs to be right for the pump/nozzles you run. the pump voltage map needs to be right for the pump/nozzles. lots of tuners (*cough* malone) use the same pump and timing maps regardless of your pump/nozzles, at least as far as i've seen for basic edc15 tunes.

i don't think there's anything "newer tech" with the nozzles you buy now vs what came in the car. i believe internally they are virtually the same. of course they can be tweaked with shims etc but afaik they are the same, just slightly different size holes, shims and springs
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
also, as far as nozzle size go, you really want one size higher up than what you want so you don't max them out with long injection times for power you expect to use frequently. that's how the OEMs work. none of the factory maps max out the nozzles. car still runs great if you are on the higher end of injection duration, but just not performing as efficiently and will have more (maybe not noticeable) smoke and higher egt which can be made worse if tune isn't good or other hardware is off
 

Turtlecharged

Member
Joined
Jun 11, 2022
Location
Los Angeles
TDI
98 MK3 TDI x 2
I tell you i most certainly had a one hell of a time, getting this engine timed right.

It kept jumping on the flywheel
You might have a damaged crank timing sprocket. The bolt can loosen up just enough to let it move. Eventually it can move enough to bend your valves.
There’s a video on YouTube about it from Cool Air VW.
Check for rusty dust around the crank sprocket, it is one of the signs the gear is loose.
 

Turtlecharged

Member
Joined
Jun 11, 2022
Location
Los Angeles
TDI
98 MK3 TDI x 2
There’s newer tech in the nozzles, the materials and the precision holes in the nozzles make for more efficiency and power. The DLC (diamond like coating) also helps them last longer. A lot has changed since the 1990s.
 
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