Tuning question

Kroner96

Kroner96

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Nov 27, 2007
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Can adding fuel without timing lower boost? I took off the factory system that was fed by a FASS and ran it straight to the pump. I can tell I gained more fuel but my boost numbers went from low 50s to 41-42psi. If I add more timing could I get my boost numbers back to where they were or maybe higher? How much timing could be run with just headstuds? Thanks
 
Sorry i didnt think about that. the combo is no plate, lazer cuts, 5x.018 injectors, 66/68/.80 turbo and a 48mm external gate, FASS, 4kgsk, 16.5 degrees timing. The only thing I changed was runnig the FASS straight to the pump. It pulls hared than before but I am only getting 41 psi when I was getting around 50. I went to a pull a few weeks back and never hit enough boost to open the wastegate. I checked for leaks and didnt find any. If I can find my plate I might throw it back in and push it all the way back. I thought I might be putting the fire out but egts still peg the gauge just as fast if not faster than before.
 
Here is what his truck was doing before:




Then bypassed the factory setup in the engine compartment and then lost boost. Any ideas for him?
 
Yes added fuel can drop boost, you can put in too much fuel and basically put out the fire.
 
Unless timing is way off raising timing typically results in lower boost.

I'd say something happened when you made the switch, something's not adding up. Unless you're putting out the fire more fuel usually doesn't result in less boost. Fuel pressure up to the injection pump would be nice to know before and after the change but guessing you don't have a guage?
 
He can get a gauge on it sometime. What timing do you think he should run? Its basically a pulling truck that sees the street.
 
I know to get the fuel supply to the pump you may have been messing around where the boost line is run off the plenum. Think you may have wiggled it loose, cut it slightly, etc.?

You said the gate wasn't opening a few weeks back at a pull. Was that with the FASS directly to the pump or like it was before you lost boost?
 
haloman said:
He can get a gauge on it sometime. What timing do you think he should run? Its basically a pulling truck that sees the street.
Click to expand...

Well with no o-rings it is a gamble to increase timing imho but I think some have done high timing with a stock gasket like and studs/torqued bolts. Try 20 or maybe more but I be not responsible for head gasket issues:p. I run 26 in my daily driver but have o-rings and 130/140ft-lb torqued new head bolts.
 
I don't Remember off the top what he has done for head work. I think studs, valve springs, keepers and retainers.
 
If the truck is pulling harder then before it's either boost line being comprimised or possibly the gate is opening up now where before it wasn't.
 
My bro runs 22* on stock bolts and gasket, with an Aurora 4k and 50psi, no problems. I would put it around 20-22.
 
Thanks for the replies. The gate wasnt opening after I ran the fuel line to the pump. I could open the wastegate easily before I switched. The afc line hasnt been on the truck for a few years now but it doesnt do anything anymore. If Im putting the fire out wouldnt egts be lower? Could I have too much pressure running to the pump? I know I need a gauge and hopefully soon I can get one.
 
If you aren't opening the gate when you made the switch and you switched nothing else I have a hard time believing you are getting more fuel somehow or the truck is pulling harder. Get the fuel pressure gauge on and let us know what you find:)
 
Kroner96 said:
Thanks for the replies. The gate wasnt opening after I ran the fuel line to the pump. I could open the wastegate easily before I switched. The afc line hasnt been on the truck for a few years now but it doesnt do anything anymore. If Im putting the fire out wouldnt egts be lower? Could I have too much pressure running to the pump? I know I need a gauge and hopefully soon I can get one.
Click to expand...

You may have just cracked your boost gauge line. And it is showing less boost. We always tend not to look at the little things. I would bet thats all it is.

Bob.
 
I thought about the gauge line too but that wouldnt keep the wastegate from opening. Once I get my clutch fixed I think im going to have the timing bumped and see if that helps, then Ill look at cutting the fuel back. What do you guys think the best way to do this would be? What would be the difference of putting the plate in and sliding it back or swapping to a different set of dvs?
 
I was originally getting at the boost line to the gauge being a possibility but the gate not opening leads me to believe you have another issue.

I can't imagine with the only difference being running the supply pump directly to the injection pump bringing that much more fuel to the situation, so much that you're putting the fire out now and not before, but I could be wrong.
 
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