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Engine Specific Info and Questions => IDI Engine => Topic started by: hamradio on July 27, 2007, 11:16:37 am

Title: How much can I turn up the fuel screw?
Post by: hamradio on July 27, 2007, 11:16:37 am: Hi,
I've heard about turning up the fuel screw on an injection pump. Some tell me to turn the screw like 1/2 turn, others tell me don't touch it. How much is safe to do, on a stock na? I don't have a pyrometer, either.
Title: How much can I turn up the fuel screw?
Post by: jtanguay on July 27, 2007, 12:02:41 pm: it's pretty much at your own risk, but you can turn it 1/4 turns and check each turn (and make note of how many turns to return it to stock) by driving the car around and making note of how much smoke is coming out (best done by a friend in case the smoke isn't too visible (high wind) ideally you want little or no smoke so not to attract much attention.
Title: How much can I turn up the fuel screw?
Post by: vvandu on July 27, 2007, 04:24:27 pm: :D I seen a 1.9 td constantly puffing out black smoke and had a very bad burning smell to it because the fuel was turned to the max... it was very quick for a stock td just from that. What are the risk involved in this? His car is still running, i guess its not healthy for the cat and your exhaust system, you should watch your EGT temp, i wouldnt turn it too much without that gauge.
Thats all i know, lol, that ive seen it cranked to the max without any care.
Title: How much can I turn up the fuel screw?
Post by: Cheesetoast on July 27, 2007, 05:42:56 pm: you shouldn't have it turned up too much without taking care of the exhaust first, a downpipe and free flow exhaust will help the egt's big time. Also dont' turn it up unless you have an egt gauge.
Title: How much can I turn up the fuel screw?
Post by: jtanguay on July 27, 2007, 07:03:36 pm: another thing is the amount of soot being deposited in your oil. you will need to do more frequent oil changes to reduce it. intercooling is a great idea to help burn that extra bit of fuel (good for around 10hp with no real adverse side effects)
Title: How much can I turn up the fuel screw?
Post by: RabbitJockey on July 28, 2007, 02:59:32 pm: i did a half turn on my rabbit i think, that or a whole turn, makes it smoke kind of bad. if i was someone that cared about my car smoking i wouldn't turn it that much
Title: How much can I turn up the fuel screw?
Post by: jtanguay on July 28, 2007, 03:12:45 pm: Quote from: "libbybapa"
It's naturally aspirated.

:roll: should have mentioned i was referring to the intercooling of his buddies 1.9TD with lots of black smoke :lol:
Title: How much can I turn up the fuel screw?
Post by: compu_85 on July 30, 2007, 01:20:03 pm: What if you have an NA pump on a TDI motor, can you turn it up too much then?

-Jason
Title: How much can I turn up the fuel screw?
Post by: jtanguay on July 30, 2007, 02:02:40 pm: you can, but i would recommend that only with a small turbo such as a VNT-15.

with a regular 1.6 turbo, there will be a lot of off boost smoke, but on boost power should be the same as a TD pump if everything is set right. a larger downpipe would help with the turbo lag, but a true TD pump is what you want.

are you using a TD motor or did you swap a TDI in there? (i'm guessing you have a mk2 from your pic) i have an m-TDI pump without the LDA, so I need to have a nice and small turbo to run it such as a K03 or a VNT-15.

i'm going to try my best to get a VNT-15 to work, but we will see how that turns out...
Title: How much can I turn up the fuel screw?
Post by: compu_85 on July 30, 2007, 03:05:30 pm: It's a 1991 ECOdiesel: Small turbo, same boost as the normal TD. It doesn't seem to smoke much. I fat fingered TD into TDI... whoops!

-Jason