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Author Topic: ahu vs 1.9idi  (Read 11871 times)

Reply #15June 03, 2012, 03:24:31 pm

libbydiesel

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Re: ahu vs 1.9idi
« Reply #15 on: June 03, 2012, 03:24:31 pm »
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.
« Last Edit: June 03, 2012, 03:33:21 pm by libbydiesel »

Reply #16June 03, 2012, 06:41:50 pm

8v-of-fury

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Re: ahu vs 1.9idi
« Reply #16 on: June 03, 2012, 06:41:50 pm »
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, ;).

Reply #17June 03, 2012, 08:01:53 pm

RabbitJockey

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Re: ahu vs 1.9idi
« Reply #17 on: June 03, 2012, 08:01:53 pm »
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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Reply #18June 04, 2012, 03:52:38 am

golftd412000

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Re: ahu vs 1.9idi
« Reply #18 on: June 04, 2012, 03:52:38 am »
the ahu is better more power and torque andbeter for economy of fuel


Reply #19June 04, 2012, 04:07:51 am

Henk

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Re: ahu vs 1.9idi
« Reply #19 on: June 04, 2012, 04:07:51 am »
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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Reply #20June 04, 2012, 10:37:13 am

libbydiesel

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Re: ahu vs 1.9idi
« Reply #20 on: June 04, 2012, 10:37:13 am »
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.

Quote
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. 

Reply #21June 04, 2012, 12:01:36 pm

1life2live

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Re: ahu vs 1.9idi
« Reply #21 on: June 04, 2012, 12:01:36 pm »
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

Reply #22June 04, 2012, 12:42:07 pm

RabbitJockey

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Re: ahu vs 1.9idi
« Reply #22 on: June 04, 2012, 12:42:07 pm »
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.

Quote
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.
01 Jetta TDI 100% stock daily
81 Rabbit:TDI-M ported head, Frank06 cam, PD intake, hybrid T3 turbo, Renault intercooler, Syl20 11mm pump, light weight fw, and yellow California Clutch clutch kit

Reply #23June 05, 2012, 02:31:05 pm

paolomarks

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Re: ahu vs 1.9idi
« Reply #23 on: June 05, 2012, 02:31:05 pm »
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

Reply #24June 15, 2012, 01:30:21 pm

Henk

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Re: ahu vs 1.9idi
« Reply #24 on: June 15, 2012, 01:30:21 pm »
^ 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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Reply #25June 15, 2012, 02:16:17 pm

R.O.R-2.0

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Re: ahu vs 1.9idi
« Reply #25 on: June 15, 2012, 02:16:17 pm »
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..
92 Jetta GLI - Black, 1.6D w/ GT2056V turbo..
86 GTI - 4 Door, Med Twilight Gray, Tow Machine..
86 Audi Coupe GT - Tornado Red, All Stock.. WRECKED.
89 Toyota 4Runner - Dark Grey Metallic, LIFTED!

Turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.

Reply #26June 15, 2012, 06:19:01 pm

8v-of-fury

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Re: ahu vs 1.9idi
« Reply #26 on: June 15, 2012, 06:19:01 pm »

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.

Reply #27July 06, 2012, 12:26:35 am

burn_your_money

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Re: ahu vs 1.9idi
« Reply #27 on: July 06, 2012, 12:26:35 am »
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.
Tyler

Reply #28July 06, 2012, 10:04:46 am

8v-of-fury

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Re: ahu vs 1.9idi
« Reply #28 on: July 06, 2012, 10:04:46 am »
Burned by Burn. Lol

didn't the corrados have the O2A as well?

Reply #29July 06, 2012, 11:09:44 am

CRSMP5

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Re: ahu vs 1.9idi
« Reply #29 on: July 06, 2012, 11:09:44 am »
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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