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General Information => General => Topic started by: AudiVWguy on March 15, 2009, 12:53:36 pm
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I had an opportunity to get on the dyno at my friends shop. Here's the printout. :D
(http://i256.photobucket.com/albums/hh177/AudiVWguy/IMG_1905.jpg)
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thats some pretty good power :) usually on a diesel the torque is higher though... that almost looks like a gasser dyno :lol: but i bet thats how Giles set the pump up.
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Well it is a 1.6. Those act more like a gasser than the 1.9.
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Yeah,
I was wondering about the torque number. There's not much happening until you get above 3000 and 10 psi. The motor has never been very torquey down low. I let off a little too soon, wasn't sure what redline I could get away with.
I'm not sure what is involved with the set up to get an accuract reading. I'll get back with him to find out.
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looks good i wonder if you could have gotten a better number if you would have wound it out to 5800 or so
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its probably best not to make much torque down low anyways... thats when you'll cook the motor or bend rods :wink:
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Hi guys. I am the one that performed the dyno test for Jeff's vehicle. These numbers are 100 percent accurate in every way. No matter how the dyno is calibrated (user calibrations) the hp will always be correct. The TQ. is a function of hp and rpm. On a diesel we always use the dyno rollers as an rpm ref and compared these to his dash tach. As long as the run matches these rpm readings after the run, we can be assured TQ will be correct as well. The numbers may have gone slightly higher if we did more runs, allowing the trans fluid/oil to thin out a little, but other than that...This is the purpose of dyno testing in the first place, to see how your setup is performing, and where changes need to be made. If I remember, Jeff is using a myriad of parts from different people and cars (inj pump and turbo/manifold, injectors) and to expect this setup to perform optimally with no tuning is a stretch. This is my guess as to why the numbers are lower than normal/expected if they are in fact so.
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This is my guess as to why the numbers are lower than normal/expected if they are in fact so.
Nope, those are great numbers for an engine that was originally a naturaly aspirated unit. It is all about the setup and what you want out of it. Big TQ means bigger boost and fuel down low which puts the stock rods into the danger zone. I'm sure that the engine could be adjusted either way for an increase, more tq or more hp, or pehaps a bit more of both. If it will hold together, you could run up the rpms and the fuel to 6k. Looked like it was still climbing and had not started to flat line yet. Either way, those are upper end stock tdi numbers you are putting out with an old 1.6 mechanical diesel. Walk tall man 8)
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Anybody have an idea what's going on between 2500 and 3k? It may have been the turbo building boost when the dyno was being held steady at wot before the ramp up of the run (only a sec. or two). Jeff insisted that he operate the throttle so there are a few things that are different like the flat vert line at the end (no biggie) and maybe that small hump at the beginning. Does anyone have any dyno graphs with something comparable?
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I would suspect that it would have something to do with the dynamic or static timing.
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Maybe Jeff can chime in and let us know what it's set at?
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I had a conversation with Giles and the timing was a little low. I also found that this pump draws in fuel so well now that it exposed some air coming in the fuel line (clear hose). Which I'm sure was happening at the dyno run. I have now set the timing to .95.
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Lift pump? If you do, it will effect the timing a bit I think. Call Giles and ask him about it.
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I was running a lift pump on the previous set up.When I install an internal pressure gauge, I saw about a 4 psi increase across the board. Giles set up needs nothing. The air in the lines was causing all kinds of havoc. New lines should be standard with a new pump.
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Not sure if this applies, but I am used to seeing air bubbles on perfectly running VW diesels through the clear feed line. I think I remember someone saying it had to do with the filter? I thought it was strange, but they assured me it didn't make much difference, as the pressure is after the pump.
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Not sure if this applies, but I am used to seeing air bubbles on perfectly running VW diesels through the clear feed line. I think I remember someone saying it had to do with the filter? I thought it was strange, but they assured me it didn't make much difference, as the pressure is after the pump.
It does make a difference. It is true the pressure is after the pump.. but those air bubbles are still being sucked in to the pump.. The fuel that comes out of the pump has to cycle through the injector lines and back through the return lines. Air in the system will cause "misfiring" and smoke as the bubbles affect the popping pressures of the injectors. The engines you saw were not perfectly running then :) well I guess it depends on the amount of bubbles really... one or two minuscule ones are probably expected, but big ones or frequent ones will cause side effects. It could be the filter, or it could be a connection way back at the tank that is slowly leaking in air as the pump sucks fuel through it, and air being lighter it will suck in easily.
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Because of the large volume of fuel being pushed thru the pump to keep it cool small air bubbles will rarely cause noticeable performance issues in the overall scheme of things... more than enough fuel will be available to the high pressure side of the pump.
Bubbles will however impact internal pump pressure on the vane pump side and therefore dynamic advance, which can cause subtle decreases in power and a potential decrease in fuel economy... my car is living proof of that at the moment.
Those little bubbles are tricky to track down... there's only so many fittings you can tighten. :roll:
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there's only so many fittings you can tighten. :roll:
hear ye hear ye!!!
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Good discussion. The cars I spoke of had very few small bubbles every 10 sec. or so.