VWDiesel.net The IDI, TDI, and mTDI source.
Engine Specific Info and Questions => IDI Engine => Topic started by: oldskool rich on December 28, 2007, 07:30:55 pm
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everyone has got there methods including myself, but was wondering if there is like sum kind of tried and tested way of producing bare horse power, like a perfect formula to get the most phisically possible out of an aaz or out of any idi?
also whos car is the most powerful?
got any pics?
i endever to build a totaly mental machine that will take the english vw scene by storm and hopfully win a few petrol heads over, but i want to see what im up against and also get sum fresh inspiration b4 i commit to my idea
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Ultimate AAZ? I am currently contemplating the same question. I purchased a new AAZ, but I dont want to install it in my car in stock form. I'd love to stroke it to a 2.0, but there are a lot of issues with doing that. To me, the next best thing would be to put a lightweight, forged, knife-edged 95.5mm crank in it. Eurospec and Autotech each have nice ones. I would also like to put lightweight forged H-beam rods in it from Kerma. Finally, I'd like to cryo the pistons and possibly have them treated with thermal and lubrication coatings.
The reason with going lightweight on everying is to get max RPMs out of it for max HP. I think this is one area that the IDIs have an advantage over the TDIs but don't exploit it.
This would pretty much take care of the bottom end. For now, I would leave the rest of the engine stock, but maybe slap the head back on with a thicker copper head gasket and some ARL (PD-150) head bolts.
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Umm IDIs and TDIs both have a 95.5mm crank. Oh and there is no way that an IDI has any sort of advantage over a TDI. Sorry to burst your bubble.
Speed costs money, how fast do you want to go?
Any modification done to an IDI (internal, obviously not IDI or TDI specific) will yield much more if done to a TDI. There is no way around it. TDIs are far superior than the IDI. Thats why MB has been using DI for so long and thats why VW has turned their back on the IDI.
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Yes, I realize that the AAZ and all 1.9s have a 95.5mm crank. But since I was just talking about putting in a 100mm crank, I thought I'd clarify.
You'll have to explain to me why having at least 25% more usable RPM vs. a TDI isn't an advantage in the HP-making department. They each have their advantages, and "that's why VW turned their back on DI" back in the early days. They wanted a diesel engine that drove more like a gasser (i.e. revs).
Whenever someone says "they're sorry", they're not. Nice try, but no bursted bubble here.
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tried and tested way of producing bare horse power, like a perfect formula to get the most phisically possible out of an aaz or out of any idi?
send your pump to Giles. include around $950. specify the power you require and what the pump will be used for. it will be returned to you with the 'perfect formula' to get the most HP (and possibly fuel economy...) out of your IDI.
other than that its all theory... you can mess around with your pump but then it wouldn't be 'tried and tested' :lol:
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Thats why MB has been using DI for so long
it may have been different in Canada but the USA they used exclusively IDI engines until 1999 and their first DI was the 2005 E320 CDI. MB's first DI passenger car engine was in 1995.
VW sold their first TDI in the USA with the 1996 Jetta. VW has made TDI's since the 1989 Audi 100 and the 1993 Golf, well before MB.
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I bored my AAZ to second oversize, ballanced the rotating mass, TDI crank nose with all ARP studs throughout (rods, mains, head). The new head has been ported and the turbo is a Garrett T3. Giles pump is a must and the PP downpipe with a full 2.5" exhaust and Magnaflow muffler. I did install a ceramic puck clutch, but it's much too agressive for street use. In the spring, it will get a 2-stage boost controler (10psi low/24psi high)and a Saab Blackstone intercooler. Later, it will get methanol injection.
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im a little confused, should i be moving up to tdi for my machine?
alot of people slate the idi, fair enough its not that eficiant but its so much more simple, all those wires on a tdi giv me a headache
what kind of power are you hiting steward sounds like uve spent alot of time and effort, got any pics?
giv it to me strait, am i gona hit 400bhp in an idi, is it even possible?
in my mind i just cant see how tdi is better, which bits make it the superior engine?
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I know a lot of flack will start, but here goes. Remember that this is only my opinion.
The TDI is more efficient, but at the cost of complexity and reliability. Those hugely dished pistons scare the crap out of me, as do the electronics. My IDI is simplicity in the extreme. I'm looking for 140-150 horsepower and somewhere around 200 ft lbs of torque on high boost. All this will be in a very driveable package that is giving me almost 70 mpg on about 7 pounds of boost and will still blow away any stock Japcar.
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I don't think anyone will ever get 400bhp out of an AAZ.
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you can get more than 400hp out of a IDI but its gonna be like merc 300td or similar...
1.9 is a bit small to those hp figures...
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i think as far performance goes tdis have no real advantage aside from being able to use propane on them
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200+hp from 1,9 Vw diesel (idi or tdi) is pretty easy. 300 is possible from TDI, IDI=? (still trying 8) ), but needs lots of work and knowledge. And then, 400hp from Merc 6 cylider 300 IDI is easy, 500+ needs work.
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Just to point this in the right direction,
Are you talking about a building an engine that will need to be driven on the street or one that is going to be high HP specific?
You can get huge power out of the AAZ if you dont mind tearing it apart after every few runs. If you plan on actually using the engine in a daily driver, that is a different animal.
I suspect that an all out HP engine would be much easier to build than a reliable high HP daily.
Cut CR way down. Get a giles pump built for Drag strip. Short straight pipe exhaust. PP intake. Nitro setup. Meth / water inj. ARP everything. Lighten everything you can. Turbo is up in the air as you will want off the line and top end, 40-50 lbs of boost.
Large tool chest to tear apart your engine on a frequent basis.
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If you want a mechanical tdi,the montego 2.0 perkins turbo diesel was a reliable lump,scrap yards are full of them :wink:
Bert
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Haven't been over here on the IDI boards for a while as at the current moment I don' t have an IDI in my arsenal anymore. However, having had experience with both motors, inside and out...modified and stock I think I can offer some insight here. Many of the comments already made here are very true and will hold up, others need some reinterpretation...
I currently have a heavily modified 1z/AHU based mTDI motor in my mk1 that I built from the ground up and is documented elsewhere here on the forums.
In addressing the reliability of the DI motors vs. the IDI motors....
Both motors have been proven to be very reliable, especially when you look at it from the strictly mechanical ends of the motors. Electronics do give the TDI a bad name (mostly in the form of MAF's and n75 valves), but the motors on a whole, mechanically are just as reliable as the next IDI. There are many TDI owners that have racked up 200K + on there cars without issue and paying attention to regular maintenence.
As far as efficiency goes. The DI motor by design is far more efficient than the IDI motors. It was one reason that so many manufacturers have moved from the IDI motors to the DI motors. Think about the design of the head and means of injection alone. In your IDI motor their is a pre chamber where the fuel is injected, combusted and then the energy is then transferred out of the prechamber through the blast ramp and finally making power when it meets the piston...in simplistic terms....
The DI motors on the other hand don't have "big scary dishes" in the pistons...that is actually a specially designed combustion chamber. Injection, combustion and power all happen RIGHT HERE at one time.
The biggest thing about these two difference is the energy loss/efficiency factor. The IDI motors waste a considerable amount of energy in the "prechamber" design. This heat is lost to the head translating in one way or another to power loss. Also, the design and direct injection of the DI motors does translate to more power/torque just by design.
I can go on...but, I could do that for quite a while...
Hope that helps?!?!
The mTDI, or mechanically controlled TDI can be created quite easily but it isn't as easy as building a "Franken pump" from many different pumps and just flying with that. There are considerations to be made in the size of hydraulic head you want to use on the pump and more importantly the design of the camplate profile and timing advance mechanism that you have in the pump. mTDI's LIKE THERE ADVANCE, and even on the eTDI's (electronics involved) one of the biggest liimitations is the amount timing advance that the ECM is able to pull, etc. Look over on TDIclub.com and you'll find that many reach this wall. Chip programming and reflash, etc. gets expensive (in this persons opinion) and I like the simiplicity of the mechanical control I have. If I have to lose a little bit of "economy" when transitioning between altitudes and super finely controlled advance (controlled by the eTDI pump), I'll take that as it; I believe, pays back in the end somewhere else. A mTDI also sounds alot more like a IDI motor...or a cummins motor if you really want to be specific do to the lack of PRECISE electronic control of timing and advance.
There are a variety of pumps out there that are good for building your base pump, or to send to Giles and have done. These include the cummins 4bt pump, Croma pumps, Perkins pumps to name a few, as well as your other parts pumps (IDI and TDI pumps).
On revving. This is not limited on the DI motors because of the design of the DI engine itself. Rather, it is a bore/stroke issue. The 1.5 is the most rev. happy motor, the 1.6...not too shabby as has been proven on the site here and elsewhere...and the 1.9AAZ....hmm, not too far off from the TDI. If the bore/stroke issue could be addressed with the TDI, you could pull more revs out of it. I remember a topic/discussion not too far in the past that discussed the feasibility of using a 1z/AHU head (same basic bolt pattern, coolant passages, etc) on a 1.6 IDI block... the biggest issue to address here would be finding pistons to fit this configuration. It would def. be a fun project....but one that involves some reverse engineering.
Anyways...my .02.
I'd love to see an IDI motor make that kind of power...even a 4cyl TDI make that... but I think displacement and overall size (as already mentioned) would limit that. Remember...there is no replacement for displacement and TORQUE, not HP wins races...
I suppose if money wasn't limited and you didn't mind cutting into your motor every few months, BIG huge power could be done...but not reliable. There has to be a balance somewhere.
I'm a mTDI guy now, building my second motor here this winter for my daily driver (b3 variant) with a proper blend of economy and power in mind... the MK1, was and continues to be just all out performance...it is fun and the TDI's are just as reliable as anything else and are a more efficient design.
Cost wise...they are more expensive but those prices are slowly starting to creep down a bit as more become available and more diesels for that matter are coming in on the market.
Have a good one!
Joe
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For that kind of power, I think the four biggest issues are reliability of the swirl chamber, piston strength, exhaust back pressure, and block flex. Some of these are IDI-specific, and some are not.
One: That is a high volume of hot combustion gasses going into and out of that little swirl chamber hole. I have heard of some people enlarging the hole, and others who have considered coating the whole chamber with a thermal barrier. These both sound like good ideas to me. As far as I know the swirl chamber is made of Inconel, so that's a good start.
Two: Piston strength. As I understand it, stock IDI and TDI pistons are cast. It might be necessary to round up some forged pistons for it. I read one of TDIMeister's posts where I think he said he knew where to get some forged TDI piston blanks that didn't have the bowl machined into them. If these are available, perhaps they could be machined with the funny little IDI swirl design on the top instead.
Three: Exhaust back pressure. As was mentioned earler, you would want to go with a huge exhaust and turbo, and have the head extensively ported. Possibly even bigger exhaust valves and different cam profile would be necessary.
Four: Block strength. 400 HP at 6000 RPM is 350 ft./lb. I don't think the stock AAZ block is up to the challenge. It is true that the TDI blocks have more webbing and internal bracing than non-TDI blocks. You could beef the block up with a girdle available from Eurospec for about $500. If you're installing this engine in a MK1, MK2 or MK3, you could make it easier by using a 1Z or AHU (TDI) block since these engines have have the proper mounts for the older cars, but are compatible with the older IDI style heads. You may still want to internally brace the block though.
Of course all of this assumes you already have lightweight forged crank and rods, upgraded clutch, stronger transmission, axles, high flow intake, intercooler, etc. The high HP TDIs also have these same issues, so no advantage there.
Obviously there are many other issues that need to be resolved, but as was mentioned by other members earler, you can fortunately leave those problems to the experts. For example, how to get the fuel and advance timing you need. This should definately be left to Giles.
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with diesels forget HP. you want the TORQUE! :twisted:
hp sells cars and torque wins RACES
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Two: Piston strength. As I understand it, stock IDI and TDI pistons are cast. It might be necessary to round up some forged pistons for it. I read one of TDIMeister's posts where I think he said he knew where to get some forged TDI piston blanks that didn't have the bowl machined into them. If these are available, perhaps they could be machined with the funny little IDI swirl design on the top instead.
This is only true of EARLY TDI engines... the 1z TDI motor has cast pistons... AHU, ALH and later motors have Forged pistons with brass truions and quite a bit beefier construction than the 1z units. Also, ring lands are thicker and the top ring location on the 1z vs. AHU/ALH, etc. pistons is different.
with diesels forget HP. you want the TORQUE! :twisted:
hp sells cars and torque wins RACES
HP indeed with diesels does not give insight into overall power. It is all about torque...and to say again what I said again in my previous post is summed up again by jtanguay.
Joe
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When I wrote to Kolbenschmidt about doing a 1.7TD, The concern they raised was not the strength of the piston crown but rather the strength of the side of the piston where the pin was connected. They said that High HP long term would cause cracks in this portion of the piston.
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sorry if i sound stupid but exactly what is an M-TDI is it just a TDI with a cable throttle instead of a fly by wire? and im guessing it has the hole knock sensor advance thingy?
so pre combustion chambers are bad, IDI pistons are good, so why cant u just use IDI pistons in a TDI?
so what head and what block?
why can IDIs hit higher revs?
im seriously thinking of moving on to TDI but keeping sum of the idi features
the car im building this engine for is a rear engined mk1 scirocco that wen finished will weigh 500kgs so i dont want to mess this up, i had the chance to hav an audi 4.2 twin turbo v8 but turned it down because everyone does that, i want to do sumthing never done before, its mainly for the quater mile but will also be "road legal" ish
as soon as caddy cums to life ill start a progress diary
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sorry if i sound stupid but exactly what is an M-TDI is it just a TDI with a cable throttle instead of a fly by wire? and im guessing it has the hole knock sensor advance thingy?
so pre combustion chambers are bad, IDI pistons are good, so why cant u just use IDI pistons in a TDI?
so what head and what block?
why can IDIs hit higher revs?
im seriously thinking of moving on to TDI but keeping sum of the idi features
the car im building this engine for is a rear engined mk1 scirocco that wen finished will weigh 500kgs so i dont want to mess this up, i had the chance to hav an audi 4.2 twin turbo v8 but turned it down because everyone does that, i want to do sumthing never done before, its mainly for the quater mile but will also be "road legal" ish
as soon as caddy cums to life ill start a progress diary
No offense on my part either, but go back through a re-read what others have said and also what I tried to draw together.
Sounds like you are really new to diesels...
mTDI is a mechanical TDI, mechanical in the fact that the pump utilized on these motors is a fully mechanical pump. The "throttle" if you will is operated by cable and the ONLY electrical connection needed is a simple ignition on/off signal to acutate the fuel stop solenoid on the pump. This is the same type of pump that was used on the IDI motors. Same TYPE...not entirely internally as there are several things that need to be taken into consideration when building an "m-pump" for a TDI motor.
"Knock sensor" ignitions are reserved for gasoline cars...not diesels. They detect "knock" indicitive of fuel/air mixture in the engine....
Diesels always sound like we are "knocking"
(Though...I can tell you stories about what diesel "knock", if you want to call it that...more pre-combustion than anything though....sounds like from my experience with propane on my old IDI motor...which I did run successfully).
As far as pistons....what we were essentially saying is that IDI pistons tend to be weak, especially without modification for HIGH power applications since they are cast units. Hence the quest for "forged" units... blanks namely so you guys could have the valve reliefs and ramp cut into them...
TDI pistons are stronger (namely your FORGED units from the AHU, ALH and later motors that also utilize coatings as well).
Why can't you use IDI pistons in a TDI block? THEY ARE TWO TOTALLY DIFFERENT TYPES OF INJECTION/COMBUSTION.
The IDI head contains the "combustion chamber" essentially for the most part for the IDI motor, it is contained in the prechamber. On a TDI, the combustion chamber is in the pistons themselves!
Putting IDI pistons in a TDI block? Ok, that could work if you used AAZ IDI 1.9 pistons...but you'd still need to use a IDI head to make the motor work. TWO different types of combustion...
IDI's themselves don't make "higher revs" Its the displacement and stroke of the motors that lend to this. Namely with the 1.5 and 1.6 motors that are pretty rev happy. The 1.9 AAZ TDI has its limitations in revving just as the 1.9 TDI motors...
It has nothing really to do with IDI vs TDI in revving...
Heads?
DI heads belong on DI blocks and IDI heads on IDI blocks. There are your exceptions (for instance, the AAZ block and the 1z/AHU 1.9 TDI block are essentially the same...minus their internals...one could use a AAZ block and build it with TDI pistons, a head, etc. and have a TDI motor)...someone on here is building one of these right now. It won't make a difference, etc. power wise...just a place and item that can be interchanged.
I'd love to build say a 1.6l or a 1.7l mTDI motor, that'd be fun... you could use the 1.9 TDI head on a 1.6 block but you have to consider the problem in finding pistons that are DI specific to do this. That would be a happy little revving monster that could be alot o' fun.
Not to mention...and I already said it above. TDI's and mTDI's especially (since you can mod your pump to allow it) LOVE their timing advance! Alot! Substantially more than you can throw at the IDI motors.
Anyways...
Joe
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I don't mean for this to become a TDI vs. IDI debate, but IDIs don't rev higher simply because of their shorter strokes. Plenty of gassers have 95.5mm and 100mm strokes, and rev to 8000 RPM. It's not about the stroke. It's about the swirl chamber in the IDI and its ability to burn the fuel faster than DI. If you want RPMs, which is essential in making HP, go IDI. That's what I intend to do.
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Gassers aren't a fair comparison however as their pistons weigh considerably less than a Diesel piston, which makes a very big difference as to max rpm.
That is probably the main reason they can rev higher.
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if you're looking for around 400hp then maybe the 2.0 twin cam PD engine is what you're looking for. IMO that would have no problem reaching 400, just bigger turbo, DP, intercooler, and a re-map.
how much was the audi twin turbo V8? if it was cheap it would have probably cost you more since they like to drink gasoline...
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I agree...it is hard to compare a diesel to gassers just from a shear design aspect. Stroke doesn't have everything to do with it...but it does play in.
Joe
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ok sorry for my beginer questions, im not much of a computer wizz it might take me months to find the answers im looking for, so please bare with me guys im trying my hardest.
i want to rev like a gasser so idi is what im going with, what can i do? i also want to maintain a large cubic capacity. wud it just meen lighten everything?
if i ran a 1.6 crank in a 1.9 wud i not get enough compression to combust?
what if i cut my block down ?
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You won't get a Diesel to the same rpm's a gasser can attain, period. Too much stresses on everything. A 1.6 has a shorter stroke, but I don't know you'd be able to reduce the block height enough. You probably would also need custom rods, plus I'm not even sure that a 1.6 crank has the same main bearing size. With a ton of torque and the correct gearing, you could keep pulling in one gear while they will have to keep shifting to stay in the powerband. That's the beauty of the Diesel. You don't need the high rpm's. The Audi R10 won the LeMans getting up to just 5000 rpm.
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lower rpm's means a longer lasting engine. i laugh at honda's that rev to 8000 or even 9000 rpm. imagine something broke at those speeds? :shock:
IDI's make their torque down low, and TDI's make it even lower (some as low as 1500 rpm or so??? with VNT turbo's)
i'd say custom tall ratio 6 speed tranny to take full advantage of the torque.
AND since it revs lower, it consumes less fuel through more efficient combustion.
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in my quest to build the ultimate idi ive found a pump that i was thinking about using, has anyone herd of a bosch vp44? its a raidal pump that aparently can deliver 1600 bar :shock: , loads more than any VE pump
has anyone come across raidial pumps?
surly this cud be adapted to fit?
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Won't matter as the injectors aren't designed to work at anywhere near that pressure. They will still open at their 150 bar or whatever it is.
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Won't matter as the injectors aren't designed to work at anywhere near that pressure. They will still open at their 150 bar or whatever it is.
lol... yep they'll open at 150 bar while the pump is delivering 1600 bar... man for some reason i just imagine a flame thrower inside the engine :twisted:
so 1600 bar is 23'206.038 psi... thats pretty close to the PD engines 30'000 psi.
maybe you can get a PD engine and try to run this pump ? use the PD block but use an ALH tdi head and this pump? that would be one mean franken engine. fully custom fuel lines... :twisted:
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i know someone who used a iveco turbo daily pump to fuel a m-tdi.
dont know if it will work on IDI...
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I'm all ears regarding the Iveco Turbo-Daily pump... Anyone used it to "sucessfully" power a DI AFN/1Z/AHU engine? Also what did you do regarding injectors?
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dont know what was done...
it was from a member of the club golf portugal.
he had a AAZ but after the crank issue nothing was left...
he bought a 90hp tdi engine and adapted those iveco pumps.
he had some troubles to make it fit and work properly but he said that the fuel was massive...
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i cant get the revs out of a tdi so its gotta be idi, im gona run a truck turbo essentualy and i believe that idi will cope with this much better.
has anyone got a diagram of how pd works? 30000 psi sounds pretty mega, how hard wud it be to adapt? whats this Iveco Turbo-Daily pump about?
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i cant get the revs out of a tdi so its gotta be idi, im gona run a truck turbo essentualy and i believe that idi will cope with this much better.
has anyone got a diagram of how pd works? 30000 psi sounds pretty mega, how hard wud it be to adapt? whats this Iveco Turbo-Daily pump about?
About impossible. Can't have a mech PD. If you are going to all that trouble just buy a PD or turn your AAZ into a TDI, like I am. :twisted: More fuel pressure doesn't mean more power by the way.
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i cant get the revs out of a tdi so its gotta be idi, im gona run a truck turbo essentualy and i believe that idi will cope with this much better.
has anyone got a diagram of how pd works? 30000 psi sounds pretty mega, how hard wud it be to adapt? whats this Iveco Turbo-Daily pump about?
About impossible. Can't have a mech PD. If you are going to all that trouble just buy a PD or turn your AAZ into a TDI, like I am. :twisted: More fuel pressure doesn't mean more power by the way.
i know fuel pressure doesnt mean more power, but its a step in the right direction, tdi isnt the answer to everything. my project must be idi, i need to find a pump that can produce more pressure than any other,
i know pd arnt mechinical but dosnt mean it wont work, just more of a challenge :wink:
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i know pd arnt mechinical but dosnt mean it wont work, just more of a challenge :wink:
A BIG challenge since they HAVE to have electronics to work by their very design. Absolutely can't work without them.
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You could have a mechanical PD-style diesel, that's what the old unit-injected DI industrial diesels were. I have some repair manuals for the type around here somewhere, it's neat to read.
But even then, even if you could "adapt" a PD to run without electronics, you wouldn't be able to use it for an IDI VW diesel of any stripe. You'd have to have an entire extra camshaft running outside the head to actuate the individual injectors.
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How do they meter the fuel?
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It's like an inline pump. It has a scroll that is controlled by a rack the is hook to the gov and accel. It changes the time when the port opens to end injection.
They basicly took an inline pump and separated it and used a cam from the engine to provide lift.
Does that make any sense? It sounds good in my head but getting it out of there and typed down in a way that can be understood is well the task of my life.
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Guess I'd have to see pics to understand.
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yeah thats kinda what i thought. Theres a plunger in a cylinder. the cylinder has a diagonal cut in it. The plunger moves up and down while the cyl twist(throttle) The diagonal cut moves so that the piston has to travel farther to reach the opening. Whe the opening is reached the fuel is no longer pressurized therefor the injector nozzle closes. no more fuel. The farther the plunger travels the more fuel is injected. I wish i had a pic for you.
Its kinda like the way the metering sleeve in the VE pump works. If your fimiliar with it?
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I guess I can kind of visualize that. But the point is a VW PD isn't going to be converted to an all mechanical engine unless it was completely redesigned with tons of custom parts, possibly a custom head, and then it would no longer be a VW PD let alone an IDI.
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i wouldn't say mech PD is impossible... in fact some of the very first diesels can be considered PD... Pump Duse meaning Unit Injector. of course some of the early versions didn't have as sensitive equipment as the pump duse engines, but the principles are the same. one injector for each cylinder fired by a camshaft.
the PD engine can rev quite high.. just as high as the IDI's. puts more stress on the camshaft (camshaft fires the unit injectors), but it can do it. the main part holding back most TDI's is the pump. Tintin wrecked some pump heads while revving too high...
simple electronics can control PD engines as well. i'll be looking into that when i start getting my conversion done.
for your IDI you actually want more fuel, and not so much pressure. the high pressure will help atomize the fuel under boost a bit better, but too much and it may reduce performance. it also messes up the timing. if you increase breaking pressure, you need to advance timing as the pump takes a bit longer to build up more pressure to the injector. with the PD's electrically actuated injection the injection is much more precise and super accurate, giving you the ability to fine tune the engine with some crazy power.
but enough about PD's :lol:
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I doubt making a simple circuit to control a PD would be terribly hard, but would probably require a lot of experimenting to get it to run really well. A pulse to let fuel in, then a pulse width modulated signal controlled by the throttle to adjust fuel quantity with the rpm controlling the start time of that signal. But it would be harder if you wanted multiple pulses per injection.
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I doubt making a simple circuit to control a PD would be terribly hard, but would probably require a lot of experimenting to get it to run really well. A pulse to let fuel in, then a pulse width modulated signal controlled by the throttle to adjust fuel quantity with the rpm controlling the start time of that signal. But it would be harder if you wanted multiple pulses per injection.
true... i've heard PD's running simple electronics... and they sound louder than our IDI's, but the factory running cars sound surprisingly quiet compared. basically pilot injection, and multiple injections per cycle really help quiet things down, and probably put less stress on the engine parts. i can't wait to start messing around with mine :wink:
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Hi,
just to came back to the rev issue compare of DI and IDI engine, one of the guys before is right. The cause for the early speed end for producing more HP at all actual DI engine is the fact, that there is not enough heat in the cylinder room to burn the fuel as fast as needed, strangely enough also becuase of the efficiency of a DI engine. The swirl chamber in the IDI engine, is all the time so hot, that there is enough heat to burn the fuel fast enough to reached 6000rpm with increasing of hp, as several runing engine has documented, there for the fuel pump modification is the big deal.
So my summary is, in efficiency the DI is better in all, thats clear and fine describe here in a early post. But in get hp from cylinder capacity, in my oppion there is no advance in DI to IDI, i even think that du to the rev issue is possible to get more hp from a IDI than a DI engine.
And also i wand to state, that hp will winn race and not torque. Don't forget, rev's don't weight, torque weights al lot, because every think must be very strong. Try to use a 200 hp motorcycle tranny with the 75 hp aaz engine, it will not survive one time pull down in a bigger gear, but is reliable for 200hp.
Best regards Clemens
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Didn't read the whole thread, but have you seen the progress that RedRotors was making with the computer controlled IDI? That seems to me to be a pretty cool step in helping things along with higher rpm control.