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Engine Specific Info and Questions => IDI Engine => Topic started by: iggi on May 15, 2005, 03:14:01 am
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My quest for a TD isn't going so well. (what patience?)
But there seem to be any number of NA diesels available in my neck o the woods.
What sort of tuning potential is there with the basic motor? I don't need a racer, but there are a lot of steep hills and traffic runs pretty fast around here. It's bad enough in my Westphalia chugging up the hills. I can't imagine what it would be like in something 1/2 the height that other drivers don't automatically register as being slow. :shock:
So.. IP tweaks and big exhaust and ?? would give you ____ in a 1.6NA?
Thanks!
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Send your pump to Giles. He can make magic happen with these pumps. Here's a good post for viewing:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=68&highlight=giles+dyno
In summary, a 1.6NA gained about 22 hp to the wheels, nearly 50%, which puts it darn close to a 1.6TD in HP specs. Add some headers for an 8v gasser, open up the intake, lighten flywheel, etc.. and you'd be showing a lot of gassers your taillights. :)
Sure, wouldnt be a racecar, but figure you wouldnt have the weight of a turbo, tubing, intercooler, etc.. and with hp close to a GTI and much more torque, it would zip. You certianly would not have a problem with hills or merging in with traffic anymore.
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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I'm curious what the effects on smoke and EGT are on a Diesel engine with about 50% more fuel with no increase in airflow...
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I'm curious what the effects on smoke and EGT are on a Diesel engine with about 50% more fuel with no increase in airflow...
My advice would be - ignore the pyrometer. Thats what I do... :D Its just far too stressful to see it pegged at 1600º.
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thanks for the info.
gives me some more options while car shopping.
I'd rather have a TD but if I run out of time I suppose I can always settle for a NA and not completely worry about being a rolling speed bump.
Cheers,
Ian
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I'm curious what the effects on smoke and EGT are on a Diesel engine with about 50% more fuel with no increase in airflow...
Dave,
I believe the magic to gile's n/a pump isn't that it puts out more fuel (though it certainly could) but that it holds the current max fuel output to a much more satisfying rpm. Essentially, it allows the engine to make the power that it really wants to.
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Dr D's right
my pump doesn't have much extra fuel and no smoke
others can attest to that.
as he says the governor mods r a big improvement and the advance
mod i do too.
Giles
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Has anyone considered what would happen if you were to remove the entire governor assembly? The shaft, flyweights, and everything..
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Has anyone considered what would happen if you were to remove the entire governor assembly? The shaft, flyweights, and everything..
It would be impossible to get the engine to idle at any stable speed if you did this. Gassers regulate themselves nicely at idle because the flow impedance of the throttle aperature increases exponentially as the airflow increases, making the system inherently self regulating. Diesels do not behave in this fashion. If the injected quantity at idle were a even the slightest bit too large the engine would rev uncontrollably, if it were even slightly too small, the engine would slow until it died. At very least the idle portion of the governor must remain in place to balance the injected quantity at idle against the engine load.
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Giles, is there anything you can do to a TDI pump?
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I don't have any dyno numbers, and my zero-60mph times probably don't mean a whole lot on your car. But here are somethings that deinitely helped.
* Adjust timing (advance it from stock)
* Adjust full load fueling (AKA "smoke screw")
* Cowl induction cold air intake plumbing (3" pipe in stock airbox front, 3" flex duct to rain tray)
* Header (it's about weight, not so much about flow) Be sure to brace it very strongly or it will crack to pieces.
* Gearing (I run a hybrid dtransmission with close ratio 1st, 2nd and 3rd gears, and tall 4th and 5th gears)
* Light wheels and tires (try to get under 25 pounds per wheel/tire fully inflated)
* Lighter flywheel. Just did this, but the results are good so far.
* Remove power steering, air conditioning (climate permitting) and other excess weight.
* If you keep the air conditioning, use a full throttle switch and relay to disable the compressor at full throttle.
If you want to modify the pump internals, governor mods and timing advance curve mods will make more power. I'm a bit skeptical of the 22hp claim (unless that's a 22hp gain over a worn out, nearly failing pump), but some real gains are possible there. My pump seems to be in good shape, so I haven't bothered to try any mods there yet (if it ain't broke, don't fix it). My pump has good pressure from the vane pump and gives decent performance already. I've been looking for a deal on a used pump to play with.
Port matching intake ports to the manifold and polishing the combustion chamber and all intake and exhaust ports is another good idea that I haven't done yet.
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Giles, is there anything you can do to a TDI pump?
Not at this time. I asked the same question about a week ago. Maybe they'll do TDI pumps in the future :)
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Well, I am going to have to say, its like making power in any motor. More air and more fuel. I would get the head ported and polished as well as the intake, and put a header on with a free flowing exhaust. While the head is off I would see about having it clearanced so that you can run a GTI cam. Then its time to send in the Pump for upgrades timming and Gov modding (with that GTI cam you will love the extra rpm's), a set of GTD nozzles. If this still isn't enough you have our wonderfull friend Nitrous, with enough additional fuel Nitrous will give you a real bang for your buck. Oh don't worry about dumping in to much Nitrous what is commonly done with diesel drag vehicals is go to the track and keep uping the jet size until it slows down and then move back to the peak jet. If you still want more at this time you will be needing to pull the head off again, look to get bigger valves put in and have it clearenced more for even a bigger more agresive cam. Still not enough? Get a turbo :P
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With a GTI cam in an otherwise internally-unmodified Diesel engine, your motor will be talking to you on the first start-up.
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Has anyone here put a GTI cam in thier diesel? I would be interested in doing it, if it would work, what would you clearance to clear the GTI cam?
With a GTI cam in an otherwise internally-unmodified Diesel engine, your motor will be talking to you on the first start-up
do you mean it would make good power or do you mean valves slapping the pistons and other fun stuff
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Has anyone here put a GTI cam in thier diesel? I would be interested in doing it, if it would work, what would you clearance to clear the GTI cam?
You need to cut valve reliefs in the pistons.
The JH cam is the worst cam you can get for a gas engine. But it has a little more lift and more duration than the diesel cams, plus it has a few degrees less time with both valves closed at TDC between exhaust and intake strokes.
But if you put a JH cam in a diesel head, the valves hit the pistons. Some relief space is needed in the piston for the valves to fit in. But Diesels also have a very small volume above the pistons at TDC, and any valve relief you machine in the pistons will increase that volume and drastically reduce compression. That would make it harder to start the engine. Depending on how much the compression is reduced, it could also affect power in a bad way.
I've thought about trying it, but I don't have a spare diesel engine around to play with, and diesel pistons are a bit too expensive to be experimenting with, at least on my budgets.
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Wow - so much info...
Seriously, GTI valves in a diesel head would not be a good thing. The Land speed truck was a 1500 and we used a Diesel block with a GTI head (carbed gas motor) - we had to notch the BLOCK BORES to make room for the valves. This shrouds the valves a lot and decreases the effectiveness of the bigger valves.
Diesel heads respond greatly to porting - pocket porting near the seat and unshrouding the valves slightly.
Running any gasoline-engined cam wouldn't work - I don't think, haven't tried it (someone that has, please post). There was one person that used a late 1.8 solid lifter cam in a diesel back in Iowa and never got it started. I would think Delta Cams or one of the regrinders could make a higher lift cam w/o affecting the duration much. Can someone talk about the issues with overlap on a Diesel - I have not read nearly as much about diesel engine dynamics as gasoline and would like to learn more.
I haven't used it, but propane injection is common with the full-size diesel crowd. Might be an interesting option to explore.
Anyone tried mechanical supercharging on a IDI VW?
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The "original" 1.5 liter Diesel SAE paper has the most detailed info I am aware about the IDI VW Diesel's cam timing, why it was selected the way it was, etc that I am aware of. Here is the link:
http://vwdiesel.net/phpBB/viewtopic.php?t=46&start=16