Low Performance Turbo Selection

[Whitetail]

Sounds like an oxy moron but all the turbo threads I found are gears towards big HP numbers. I wanted to start a thread on a low budget turbo kit based on ebay parts with the goal of <10 PSI quick low end boost that will give a little bit better around town drivability without sacrificing engine longevity or much MPG. Something a little better than what would be stock on a 1.6TD from VW. I dont know a whole lot about AR numbers or what makes better low or high end boost, logic would say a smaller turbo make quicker boost but the 1.8t has a tiny turbo and all the boost is at the top end. I see other people talking about maps? What is that and how do you read?

Thinking about
TDI intake $75 (or I may try aluminum welding with my mig and use the factory 1.6 one with a plate and some pipe)
cast 8V T3 four bolt manifold $75
Generic T3 Turbo $150~$200
Generic intercooler $120
Oil lines not sure, there should be pressure somewhere on the block, return drop the pan and weld a nip?
Exhaust can fabricate

Anything else missing?

[vanbcguy]

For low pressure, quick spooling you do NOT want a T3.  That's waaay too big.  You want the smallest turbo you can find really - you're looking for something that will provide down low boost at a reasonably low pressure ratio.  All the T3 series turbos are going to be too big by far - the one that came on the 1.6TDs originally is the 'best' of the T3 family and it won't do what you're looking for here.  Basically the larger the turbo's turbine section, the more exhaust flow it will take to spin it up.

A perfect turbo for that would be the stock one found on an AHU or 1Z engine.  It's a simple wastegated turbo meant for exactly what you are talking about, and has the happy coincidence that it is usually found attached to a nice small VW 8V manifold designed to fit with the engine mount styles found in Mk2/Mk3 cars.

Compressor maps are the most commonly found maps.  They will have pressure ratio on one scale and airflow (usually measured in lbs/min) on the other.  The map will show you approximately how efficient the compressor will be at a given combination of pressure and airflow.  There's a few tools out there to help plot values against a map, it'll take a bit to wrap your head around.

[RabbitJockey]

yeah you really cant beat the stock tdi turbos for what you want, and they're low hanging turbos so you could even run a gas intake manifold with them if you wanted.  the smaller idi turbos would all be good too.

[Whitetail]

So according to wiki that's tdi from 94 to 02. Ill call some yards next week and see if I can find anything.

That flange style with the 3 bolt manifold seems harder to get. The t25 and t3/t4 manifolds are readily available for 8v vw. Maybe a small t25 would be good? Like this... http://www.ebay.com/itm/231394009711

[libbydiesel]

At 99.5 in the jetta and all of the early new beetles got the vnt turbos which are better performance both at low and high rpms, but are more complicated for install.

[vanbcguy]

So according to wiki that's tdi from 94 to 02. Ill call some yards next week and see if I can find anything.

That flange style with the 3 bolt manifold seems harder to get. The t25 and t3/t4 manifolds are readily available for 8v vw. Maybe a small t25 would be good? Like this... http://www.ebay.com/itm/231394009711

You'd be looking for an AHU or 1Z ideally.  The 1Z was in Passats starting in '96, the AHU was in the Jetta/Golf starting in '97.  As Libby mentions they went to VNT turbos starting with the Beetle in '98 and then the Jetta/Golf in late '99.

Check http://www.car-part.com/ - there's a bunch of manifolds + turbos on there for about $150.  It's an online directory of wrecking yards - I got my BHW exhaust manifold through that site.

[Hdriven]

This topic is interesting. I've been thinking of something like this too. What sort of fuel upgrades would be required to run this small turbo setup?

[TimpanogosSlim]

This topic is interesting. I've been thinking of something like this too. What sort of fuel upgrades would be required to run this small turbo setup?

You might be tempted to cut the collar off of the smoke screw on the IP.

A turbo pump allows you to not smoke under no boost. That's the major difference.