AHU versus ALH power???

[dogdots]

I am contemplating a future purchase of a Mk III Jetta and am curious if I can attain the same tire shredding power from a Mk III as I have with my Mk IV for about the same cash outlay for parts.

My daughter has decided she likes my Jetta way more than the 5.0 convertible Mustang we bought to restore. I would like to find a nice Mk III for her if I can get the power she wants to match mine.

 

[Bob_Fout]

Peak power you can, but IIRC not power across the rev range. The MK IIIs have a wastegated turbo vs. the VNT-type in the ALH.

 

[hgeittmann]

fuel pump needs to be upgraded to ALH 10mm or 11mm to get beyond 135hp (give or take a few).

 

[Rub87]

AHU has 10mm pump..

Put afn or asv injectors in it and up the boost..

 

[cowboyjack]

Have you looked at Scott's A3 on stealthtdi.com?

I found his info. very useful for pricing out power mods on my A3 by tracing catalogue prices for the mods he used on his car.

 

[GiGGer]

I've had 2 AHU/1Z engines. One in a Passat 96 and the other in a mk2 swap with a 98 AHU.

I've always found that it's lacking top-end power. After 3000 or 3200 RPM, even with a RC3 / .205 nozzles, i've also add a 12mm pump head/plunger with no change.

I never swapped the turbo. BleachedBora now got a Hybrid Stage 3, need to try this one!.

Mojogoes suppose to have over 250 hp on a mk3 engine.

 

[AThreeTdi]

With enough mods like mine it will pull to 4500 with no problem..

 

[GiGGer]

With RC3 and .205 nozzles. racing in 4th gear from 3000 RPM and up with a stock ALH Jetta, I was not able to pass the ALH. but, from low end RPM, I was like a rocket beside him.

After adding a 12mm pump, absolutely no change. Same quarter mile speed (nothing official, just from a sign to another sign on the road I test my cars)

The turbo is probably the solution to lack of high end power, engine isn't breathing enough.

 

[Bob_Fout]

Something is very wrong if with RC3 and .205 you could not beat a stock ALH. You should be beaten the stock ALH in rather easily.

 

[GiGGer]

That's what I think...I did check everything..Intake was clean, wasn't too much horrible before cleaning, timing was check very precisely, MAF and N75 are new, boost is very constant at 18.2 PSI even from 3k to 4k, but no additionnal power. Tried with the EGR disconnected, don't exactly remember what i've check on that engine, it was 2 years ago.

I've change the 0.205 nozzles and went to PP502 (0.232). Gain in low/mid but same problem in high end rpm. trap speed on my road track was still 130 km/h before and after the 2nd upgrade nozzles. I've tried with the 12mm, absolutely no gain no my trap speed with the 12mm and pp502. compare to 10mm and 0.205.

 

[AThreeTdi]

New down pipe and cat delete(off road use only) seem to make a big difference, hopefully I'll have one of the Bleachedbora stage III turbo's to try soon..

 

[jackbombay]

The A3 is 600 pounds lighter so it can make notably less power and be just as fast as the heavy A4's.

 

[hgeittmann]

AHU/1Z have 10mm pumps, yes. My point is that the ALH 10mm pump can supply higher pressure (and more fuel) than an AHU/1Z 10mm pump.

 

[hatemi]

Aliagtor can make a remap able to controll VNT for AHU. Then all you need is larger nozzles and a proper turbo. There are few 230-250hp AHUs in Finland so the base engine isnt the limiting factor.

 

[mrchill]

You'll find that available timing in the AHU\1Z pump is significantly lesser. This can be fixed. You will also find that a lift pump helps a lot with the high rpm fadeout. Mapping helps a lot. The correct pressure helps more and of course, the right exhaust and turbo. One can even run the vnt and tuning on a Mk3 and have quite the tire scorcher. Loads of options should you dare........

And Jackbombay is right. The Mk3 is so much lighter, and far more nimble, that outgunning a Mk4 should not be a huge problem with similar mods.

 

[GiGGer]

11mm ALH pump could be a good choice. I really want to try the lift pump this time. The race against mk4 I was driving a B4 TDI. about the same weight. Still should have passed him.

I'll probably stay with wastegate turbo and give a try at BB's Stage 3. cheaper than going VNT.

 

[Rub87]

the diffrence is in the cam...

 

[Stealth TDI]

Not being able to outrun a stock ALH is a problem. I was fooling around with a group of TDI fans who drove from Northern CA to Southern CA for a TDI gathering years ago. We drove the Grapevine Pass, a long steep grade north of LA. I had just a chip and B205s... perhaps around 105 whp. I had no problem passing a stock ALH on that climb. Now I have 136 whp. I'm sure I'd leave one in the dust now... until my EGTs put me out of commission.

Still, I'm nowhere near the kind of power made by ALH's. I'm a touch jeaous of that. But then I have to recall that my power to weight ratio is the same as an A4 with 30 whp more. I hope to have one of BB's Stage III turbos to test soon. I don't think it'll give me 30 whp. But I hope to report something good.

Take Care,

Scott

 

[dogdots]

Now that's something...

Aliagtor can make a remap able to controll VNT for AHU. Then all you need is larger nozzles and a proper turbo. There are few 230-250hp AHUs in Finland so the base engine isnt the limiting factor.

That would be a great solution If we could put a VNT-15 or 17 on a AHU motor and have software written to control it with the factory ECU without changing the cluster and ECU. I would be happy with that.

 

[IndigoBlueWagon]

AHU and 1Z engines make great torque, especially the 1Z in the Passat. But they don't have the HP potential that the ALH engines have. I think it's fuel, as already mentioned, and breathing. And perhaps intercooling. My Golf with RC3+ and stock nozzles feels significantly faster than my '97 with RC3+ and 357s. And they weigh about the same: the Jetta has a published weight of 2700 and I've weighed the Golf at 2680 (no rear seat or spare tire). In similar tune the Golf makes about the same torque as the Jetta but about 10 more HP, even though the Jetta has a lift pump.

 

[oilhammer]

My A3 ran like a bat out of hell. Biggest advantage the A3 has is its much lighter. Although the A3's stock suspension (save for the VR6 cars) really cannot cope with the added power. I had an early Upsolute chipset, the 2.5L TDI 5 cyl injectors, TT downpipe and mufflerless exhaust, and it would EASILY turn the Michelins into molted piles of stinky French rubber.

Good thing is, the older [stock] turbo is tougher, the A3 already has the better clutch. Keep in mind the AHU is more likely to smoke with heavy mods than a properly tuned ALH.

 

[hgeittmann]

That would be a great solution If we could put a VNT-15 or 17 on a AHU motor and have software written to control it with the factory ECU without changing the cluster and ECU. I would be happy with that.

Jeff at RC converted an 021GQ ecu (several other versions w/ no immo can also be converted) to 021GN for me. I run a pd130 turbo with AFN manifold on my 1Z. It's nice. I don't think you can simply remap an ecu designed for a wastegate to run a vnt (or I'm assuming both Jeff and Aligator would've said so). The vnt conversion requires some fab work as there is no plug/play vnt turbo for 1Z/AHUs (BB wastegate hybrids are drop in upgrades), but if you enjoy that sort of thing, it's a worthwhile effort.

My wife just got a new car, so now I've got her B5 as my daily, and the B4 is now my dedicated project car.

 

[Rub87]

Why would a ahu have less potential dan an alh?

When not looking at the intercooler when you have a ahu with similar nozzles and turbo the only thing that can be the problem is the sucky AHU cam..

Throw in an ASV cam and you're done with that..

The pump shouldn't be the problem, you will have enough advance for 4500rpm, and knowing that @4000 rpm that turbo becomes way to small..

Ports in the head are the same.. + and AHU has no dual mass flywheel so you won't have problems with that eighter..

PS I forgot the AHU has suckier intake manifold, but I swapped an AFN one on mine that time..

My vnt17 ahu was running 1.3 bar and race520 nozzles, this was without much smoke, stock intercooler, stock cam, stock exhaust, it was faster than a 170PD leon2

 

[hatemi]

The stock ecu can be made to controll VNT. All that is needed is the change of N75 for a different model.

Put in a VNT20+ and R520 and it would kick ass. Change the pumphead to 12mm if that isnt enough. Thats pretty much the thing thats needed for 200hp. The stock exhaust manifold can be used with larger turbs with an adapterplate. That thing starts to realy restrict after 200hp but till that point it can be used.

And if that cam is a problem it can be reground. And the head ported. The list goes on. You need to do pretty much the same things as you would need to do with ALH to get real power.

 

[dieseleux]

A big problem of AHU is K03 turbo, to much manifold pressure, K03 is good for fast spool, high torque at low rev but not for high rev and high intake pressure.
Another problem is 11mm head on original pump, with this mod, no or small gain, you need to setup dynamic timming in pump.
On my pump with my 11mm head, i missed 5 degree at high rev and 2-3 degree at 1800rpm at WOT.
This problem is same on ALH pump with swap head, see log in group 4 with vagcom.
Old AHU (aprox. 1992-94) have different cam plate, North American AHU (1997-1999), 1Z (1996-97) and ALH (1999-03) have same cam plate in 10mm version.



Dieseleux

 

[Rub87]

AHU in europe doesn't have K03 on them..

More like K14 or K15..

You can push these thingies reliable to 130hp..

 

[Rub87]

Btw I have an AHU pump in my current setup with 12mm head.. 192whp without troubels, don't have any timing realted problems with it..

 

[jackbombay]

I don't think you can simply remap an ecu designed for a wastegate to run a vnt...

The stock ecu can be made to controll VNT. All that is needed is the change of N75 for a different model.

Yep, 2003? 2004? was the first time I read about t being done.

Somewhere around here there is a thread started by drivbiwire detailing the IP swap to an ALH pump, it think he used bits from diesel geek which I don't think are available anymore though.

 

[GiGGer]

a link on vortex with the conversion for an ALH pump to work on a AHU

http://forums.vwvortex.com/zerothread?cmd=print&id=3438594

 

[turbo johan]

A difference between AHU and ALH is that 1Z/AHU haven't got bronze bushings around the pistonpin.
They'll wear out more easy then the ALH pistons.
With 1Z im carefull, i've seen some with broken pistons.
AHU's are a bit stronger.
Camshafts are big difference on ALH and AHU.
187 dgr. and no valve overlap, there good for torque in low rpm.
But totaly useless for high topend.

AHU's run really nice on VNT.
PP764, GT1752V, AFN intakemanifold, AFN exhaustmanifold, ALH cam, custom chip with vnt control.
160 hp & 400 Nm