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Engine Specific Info and Questions => TDI Engine -General Info => Topic started by: 1life2live on May 23, 2012, 11:55:20 am
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I currently have a 1984 jetta with a 1.6td with the fuel turned up and the boost set to 20psi. I was planning to swap in a tdi out of a 97 jetta that i bought as a complete running car. I have just been offered a 1.9 idi with only 40k on the clock with the reciepts showing when it was installed. Im now looking for advice on the best direction to go whether i take the time to swap in the tdi or go the easy route and bolt in the 1.9. Is there a big power difference between the two? What are the pros and cons between the two engines and is it worth the extra time and hassle to do the tdi swap. I had plans of bigger injectors and a chip on the tdi but i could spend that money on modding the pump on the 1.9. Any help would be great
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The AAZ and AHU/1Z will make similar power provided they are both intercooled, similar turbo efficiency, etc. The TDI does not like to rev as high, is about 10-15% more fuel efficient and cannot drop pre-chambers.
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crazyandy did some math for me... my tdi-m is pullin aprox 6200rpm... at that point no more pull.. stock 98 02a, 3rd gear 78mph via gps.. 21psi of boost on the stock pea shooter tdi turbo too....
imo biggest differance.. no pre cup to drop.. no glow plugs required unless sub 20*f too.. but i have yet to drive a aaz to see how it feels vs my tdi-m..
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What exactly is the pre chambers? I plan on inter-cooling either motor and would like to do some mods to either of them. I know it will be easier to do the aaz since I won't be dealing with the computer and I also won't have to worry about the egr. Something about being able to tune the ecu on the ahu is tempting to do the extra work.
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prechamber is the swirl chamber the injector/glow plug go into on a idi head.. for somereason some fall out as you drive and kill what was a good engine..
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Ok that's what I thought u were talking about. My friend had that very thing happen to him after a machine shop resurfaced his head and removed them. They didn't stay in after they re installed them and trashed the motor.
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crazyandy did some math for me... my tdi-m is pullin aprox 6200rpm... at that point no more pull.. stock 98 02a, 3rd gear 78mph via gps.. 21psi of boost on the stock pea shooter tdi turbo too....
imo biggest differance.. no pre cup to drop.. no glow plugs required unless sub 20*f too.. but i have yet to drive a aaz to see how it feels vs my tdi-m..
I've driven a couple aaz mk3s and they are DOGS compared to the ahu.
No way ahu/aaz make similar power in my book.
Plus, ahu is less smokey, and easier to find parts for.
Egts are wayy cooler too.
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When stating that they will produce similar power, I wasn't talking about stock form. In stock form the AAZ was one of the most de-tuned piles of steaming dog poop that VW ever produced, rivaled only by the 1.6ECOdiesel.
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1.9 AAZ 105-7tq stock compared to the 1.9 AHU 150tq stock. Stock the AHU would be way quicker, not to mention the always spooled k03 hitting max torque at 18-1900 rpm.
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1.9 AAZ 105-7tq stock compared to the 1.9 AHU 150tq stock. Stock the AHU would be way quicker, not to mention the always spooled k03 hitting max torque at 18-1900 rpm.
Pretty sure stock tq on the aaz is more like 120 not 105.
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I looked it up, 1.6TD was rated at 69 HP @ 4500 RPM and 98 ft.lbs. @ 2500 RPM. The 1.9TD (AAZ) was rated at 75 HP @ 4500 RPM and 114 ft.lbs. at 2500 RPM.
Right in between the both of our guesses.
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Even if the AAZ and AHU made the same torque rating, the fact that the AHU makes it at 1800 as compared to 2500 is what you are going to feel while driving it.
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Add an intercooler (like the AHU has) and appropriate boost fuel enrichment (like the AHU has) and the AAZ will produce similar power/torque to the AHU. It will produce it somewhat later in the RPMs, will be comfortable revving higher and will consume 10-15% more fuel in the process.
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or get an AHU and add a decent FMIC, more fuel, more boost and get even more power again, for probably very little drop in economy
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BUT the 1.9idi is basically 1 wire to run engine.
VS The sensor-laden electronic TDI
I've had both, love the simplicity of the iDI, but have found the ahu with 205 nozzles tdi to have more power - as I ignore the CHECK ENGINE light as accelerating...
Although I lean to the simplicity of the IDI
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or get an AHU and add a decent FMIC, more fuel, more boost and get even more power again, for probably very little drop in economy
You are missing my point. Those additions to an AAZ will ALSO make the additional power. The two engines have similar power potential. The AAZ revs higher and could drop a pre-chamber and self-destruct. The AHU consumes less fuel. Pick your poison.
I currently have an mTDI vanagon w/ 5-speed manual trans and love it.
I also have a vanagon w/ a stock automatic trans. I can fit either AAZ or AHU. I will probably choose the AAZ because I can create similar power and the stock gearing is more compatible to the rpm range of the AAZ. Yes, the AAZ will consume more fuel and a custom R+P is now available, but based on a $4 / gallon cost of diesel it will require driving between 150,000-180,000 miles to recoup the cost of the custom gearing based on fuel savings alone. This is also ignoring the fact that the installation of the AAZ is less expensive/less work to install. The AHU will require either waaaaay more electrical work or a properly built mTDI pump. I have the knowledge and experience to build a proper pump with ease and so I didn't even factor that cost in. Someone without that knowledge or experience is looking at even more miles or possibly never recouping the added cost of the installation. If the AAZ ever drops a pre-chamber then the reduced initial cost would be nullified.
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BUT the 1.9idi is basically 1 wire to run engine.
VS The sensor-laden electronic TDI
I've had both, love the simplicity of the iDI, but have found the ahu with 205 nozzles tdi to have more power - as I ignore the CHECK ENGINE light as accelerating...
Although I lean to the simplicity of the IDI
I have a 1 wire Vw oem ahu TDI in my car right now, ;).
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I have always thought an aaz dressed the same as a tdi would perform similarly. Also keep in mind stock tdis had a 10mm pump as well. And no aaz came with an intercooler. Tdi has the advantage of lower compression which makes it possible to run more timing advance for better fuel mixing, the lack of hot prechambers helps there too, aaz has better port design because it doesn't need the swirl and also has the prechambers which is an advantage at higher rpms since it helps burn the fuel faster. Honestly in an all out build unless a tdi can be made to rev as well as an idi I think idi would make more power since power is mostly about how much air you can move, and revving higher and boost is the only way to do that
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the ahu is better more power and torque andbeter for economy of fuel
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libby you have very valid points and i'm agreeing with all, but surely an AAZ will never make as much as an AHU? I'm hoping to see 150 at the wheels with mine, and I don't know of an AAZ's that'll do that
Again i guess it just comes down to easier and cheaper to install VS potentially (and stock-ly) faster and more economical.
Got to say i'd never heard of this cup-dropping thing over here, maybe the engines over there were worse built/designed than over here
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the ahu is better
That's true, it is better because it is a more efficient engine.
more power and torque
[cough]bull$hit[/cough]
andbeter for economy of fuel
Yup.
libby you have very valid points and i'm agreeing with all, but surely an AAZ will never make as much as an AHU? I'm hoping to see 150 at the wheels with mine, and I don't know of an AAZ's that'll do that
Nope. If the AAZ had been fitted with intercooler and with appropriate boost fuel enrichment like the AHU was, then it would have made the same power as the AHU. I have seen dyno sheets for the 1.6TD with over 200hp. 150hp at the wheels with an AAZ would be relatively easy (for some/me) to achieve. The AAZ will consume 10-15% more fuel for that power with the accompanying added emissions and there is an massively increased load on the cooling system because that 10-15% of extra waste heat ends up there, but that's it. Actually as Trev was saying, probably on an ALL-OUT performance build, the AAZ would slightly outdo the AHU because it will produce that same power/torque at a 10-15% higher rpm and so at the point where the bottom end is the limiting factor, the AAZ will survive slightly longer just because of the added revs.
Again i guess it just comes down to easier and cheaper to install VS potentially (and stock-ly) faster and more economical.
Got to say i'd never heard of this cup-dropping thing over here, maybe the engines over there were worse built/designed than over here
Nope. It really just comes down to long-term fuel economy and taller gearing vs shorter gearing and less initial cost/labor.
The pre-chamber thing is minimal (unless it happens to you). Even on maxed out engines it probably happens less than 2% of the time. The cost of a new engine 2% of the time still does not offset the added work for an eTDI or the added cost of a properly built mTDI pump.
Don't get me wrong, I'm not a proponent for the AAZ over the AHU or vice versa. They are both fine and depending on one's priorities either can be the better choice. I just have a low tolerance for nonsense and the comparison of the stock hp/tq of the two engines is nonsense. They were fitted with different engine management and external performance parts and those differences account ENTIRELY for the difference in performance. Fit an AAZ with the appropriate fuel, an intercooler and 15% shorter gearing and you won't be able to tell the performance difference with an AHU until you get to the pump and fill it with fuel. Like I said, I'll probably run both in different vehicles and both would be the right choice in their particular application.
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All great input and info on the matter. I bought the aaz it was fitted in a quantum wagon for 700 and the local recycler will give me 300 for the car without the motor so I'm getting a 40,000 mile for $400. I already own a complete tdi Jetta and think I'm going to stick with the plan of swapping it into my Jetta this winter. My close friend who painted my Jetta this winter for free I might add is getting the aaz for his mk2 Jetta since his 1.6td is on its last leg. So I guess he's getting the smoking deal of a $400 aaz
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the ahu is better
That's true, it is better because it is a more efficient engine.
more power and torque
[cough]bull$hit[/cough]
andbeter for economy of fuel
Yup.
libby you have very valid points and i'm agreeing with all, but surely an AAZ will never make as much as an AHU? I'm hoping to see 150 at the wheels with mine, and I don't know of an AAZ's that'll do that
Nope. If the AAZ had been fitted with intercooler and with appropriate boost fuel enrichment like the AHU was, then it would have made the same power as the AHU. I have seen dyno sheets for the 1.6TD with over 200hp. 150hp at the wheels with an AAZ would be relatively easy (for some/me) to achieve. The AAZ will consume 10-15% more fuel for that power with the accompanying added emissions and there is an massively increased load on the cooling system because that 10-15% of extra waste heat ends up there, but that's it. Actually as Trev was saying, probably on an ALL-OUT performance build, the AAZ would slightly outdo the AHU because it will produce that same power/torque at a 10-15% higher rpm and so at the point where the bottom end is the limiting factor, the AAZ will survive slightly longer just because of the added revs.
Again i guess it just comes down to easier and cheaper to install VS potentially (and stock-ly) faster and more economical.
Got to say i'd never heard of this cup-dropping thing over here, maybe the engines over there were worse built/designed than over here
Nope. It really just comes down to long-term fuel economy and taller gearing vs shorter gearing and less initial cost/labor.
The pre-chamber thing is minimal (unless it happens to you). Even on maxed out engines it probably happens less than 2% of the time. The cost of a new engine 2% of the time still does not offset the added work for an eTDI or the added cost of a properly built mTDI pump.
Don't get me wrong, I'm not a proponent for the AAZ over the AHU or vice versa. They are both fine and depending on one's priorities either can be the better choice. I just have a low tolerance for nonsense and the comparison of the stock hp/tq of the two engines is nonsense. They were fitted with different engine management and external performance parts and those differences account ENTIRELY for the difference in performance. Fit an AAZ with the appropriate fuel, an intercooler and 15% shorter gearing and you won't be able to tell the performance difference with an AHU until you get to the pump and fill it with fuel. Like I said, I'll probably run both in different vehicles and both would be the right choice in their particular application.
couldn't agree more, i might doubt the difference in fuel economy being that much but i suppose when an aaz would get 45mpg, a tdi might get 49.5-51 mpg all else being the same. but idis have been known to get plenty good mileage. i think the myth of a tdi being so much superior power wise is the difference between a 1.6td vs a 1.9tdi which is all most people in the US have ever experienced. and as you've said the aaz had completely inadequate boost enrichment, and a smaller pump head and no intercooler. and also the difference in gearing since any tdi came with an 02a or 02j, and all idis had 020 or 010. and also like you've said, i've seen plenty 1.6tds get well over 150whp, and quite a few aaz's with over 200. either way they're all great engines id drive any of them in a heart beat.
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I'm interested in going the TDI route for my diesel vanagon in the future. I like the simplicity of the IDI's and therefore like the idea of a M-TDI. I have rebuilt very successfully both a 1.6 and a AAZ injection pump ,(dismantled it completely and replaced all seals, bushings, rollers, cam plates , etc) Do I have the skills for a MTDI? What all does it involve? Paolo
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^ you've already done more than me and i'm doing an m-tdi so go for it. as you see i ask lots of questions about it, and i'm getting there :P
Learn something new every day, we don't really have much in the way of powerful TD's over here, they rarely see over 100, 120bhp which is why i assumed they weren't as good as the tdi.
As i said, something i have little, almost no first-hand experience of.
What would be required then to see such high numbers (about double stock?) from an engine like that?
Just trying to estimate what a TDi with a 2.5L 300TDi pump and VNT20 could do in comparison
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BUT the 1.9idi is basically 1 wire to run engine.
VS The sensor-laden electronic TDI
I've had both, love the simplicity of the iDI, but have found the ahu with 205 nozzles tdi to have more power - as I ignore the CHECK ENGINE light as accelerating...
Although I lean to the simplicity of the IDI
I have a 1 wire Vw oem ahu TDI in my car right now, ;).
its made with OEM pieces.. but its FAR from OEM.. VW never made any mechanical direct inject motors on this side of the pond, did they?
now, had you pulled that out of the car as it sits, then yes, it would most definitely be OEM/Factory..
i like going with non-oem parts, or OEM parts for SOME OTHER engine..
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I have a 1 wire Vw oem ahu TDI in my car right now, ;).
its made with OEM pieces.. but its FAR from OEM..
OEM= original equipment manufacturer. So, I am in fact 100% OEM. :) Everything used in my M-TDI AHU was Volkswagen parts. Not one piece of aftermarket.
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and also the difference in gearing since any tdi came with an 02a or 02j, and all idis had 020 or 010.
B3 Passats came with an AAZ and 02A tranny.
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Burned by Burn. Lol
didn't the corrados have the O2A as well?
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yep... no room for a 020 due to inner fender like on a b3... but anything can be made to fit... like in my b3...
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mine came with a o2a from stock.but short geared so i swaped to a cyp and that make all the difference.
i have a 1.9 idi and with the cyp gearbox its all that some can ask for (in normal use.)
its intercooled(front mount),proper oil cooling system,vnt 20 and custom intake manifold.
most of the IDI“s problems were solved there.
did a 650km trip with speeds around 160 going to there and 180 comming home and it still averaged 6.8l/100km!
thats in a 35i wagon,dragging heavy widened steelies and 5 people inside so i am pretty happy and say no to people that say only tdi“s are the way to go to achieve that... ;)
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my modified aaz in an mk2 is 2-3 times faster than the 1.9alh tdi in a mk4 as far as my butt can tell. BUT that was a massively worked on AAZ with lots of fuel, dynamic timing advance, no gov., FMIC, 2.5" open exhaust, lots of porting, T03 Garett @ 26lbs.
The biggest advantage I see with TDI's is the ability to run propane and NO2 without much concern. (again the benefit of no pre-chambers as mentioned earlier). The AAZ is easier to work on for sure and much cheaper.
I got 50mpg casual driving and melted the tires driving it like i stole it. Never saw higher than 1,200F EGT. I dont know what the TDI's typically do stock with that VNT in it.
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did a 650km trip with speeds around 160 going and 180 comming home and it still averaged 6.8l/100km!
thats in a 35i wagon,dragging heavy widened steelies and 5 people inside so i am pretty happy and say no to people that say only tdi“s are the way to go to achieve that... ;)
^ this is remarkable...
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my modified aaz in an mk2 is 2-3 times faster than the 1.9alh tdi in a mk4 as far as my butt can tell.
You can't even compare a beefed AAZ to a stock ALH. However, a tune and injectors on that ALH would sure change your mind ;). No other work needed then that and you make some serious power. Reliably all day long. That's really where the advantages come in with the TDI (not necessarily saying the Direct Injection) just the next gen VW diesel engines. Specifically the ALH, it was built to withstand 3.5-4x more than what it produced stock.. with factory components. That is what makes them better in my eyes.
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That is something else that should be mentioned is how much the different nozzles effect performance on tdi, which is nice I am guess this is because there is no swirl chamber
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The stock nozzles are undersized and are only capable of stock fueling. They are not like the idi nozzle where stock they are 50hp but those same injectors will glow 225hp of fuel.