Check this out - [Fwd: My Turbo Audi 2.0 Project (not short)]

[T Berk <tberk@mindspring.com>]

Folks, 
as you read this you will notice a few things:

It ain't me, it's some guy named Frank, from another list.
Seems the guy thinks out his projects.
It is meant to be installed in a Vanagon; usually a flat four type vehicle.
(Diesels in these were I-4 motors though).

Still, I asked if he would mind if I 'published' his note and he said,
No Prob Bob. 
Or words to that effect.

enjoy,
TBerk
Striving for value added list participation



<mailto:FrankGRUN@aol.com> Frank wrote:
> 
> I'm actually rather excited about this (smile). Been working on this idea for
> several years. As I have often stated, I converted the diesel to the 1.8 L 8V
> GTi engine from a '90 GTi a very long time ago. It has done every thing I
> have asked of it save for two problem areas: lack of Moxie in the mountains,
> and inadequate humph when running at 75 and faced with the need to pass.
> 
> After reading the reports of an extended mid-life crisis when Brian (?-sorry)
> squeezed in a Subaru 6,  I got more serious. I had entertained the possibility
> of a 1.8 turbo, but it wouldn't fit without engine cover mods. Likewise the
> VR6 and the ABA. Of course, the 1.8T, the TDi and the VR6 were all eliminated
> because of financial reasons. I must be very careful around SWMBO. Hiding
> cash, milk money, recycled bottle returns etc, and its hard to score a few K
> that way.
> 
> Anyway, the 3A has always had my eye. Cheaper in the national yards since
> they don't move compared to the ABA (just an Audi 4 you know). As you are
> aware, the 3A has the same block height as the RV digifant 1.8 L, but an
> honest torque enhancement. In looking at the engine internals, I discovered
> that all 3A's have a forged crank, and only the early ABA's (up to '95) are
> forged. The later ones are cast. Also, the 3A has piston cooling oil
> squirters, while this appeared on the 96 and later ABA's. For a while, I was
> going to swap over the head from my digifant, use the same simple engine
> management system, etc, etc. But then I got my hands on the 3A engine and
> discovered that there were several real differences as compared to the ABA
> and the Digifant heads (always planned for a 8V engine and a non-crossflow
> design for more torque). As opposed to my digifant head, the fuel injector
> ports are in the intake manifold and not in the head. David Marshall alerted
> me to the fact that this is a temperature bonus for the fuel injectors. Of
> course he remains fixated on these arcane CIS systems, so I'm sure he didn't
> appreciate some of the more subtle ramifications of this!
> 
> Anyway, taking off the Audi manifold and comparing it to the Digifant
> version, the Audi intake ports were much larger with what appeared to be a
> cleaner flow pattern. After some research, a bit of engineering and a few
> hours on the lathe, I have built a set of modified injector ports to let me
> use the Bosch (Digifant and LH-Jetronic ) injectors on the Audi manifold. To
> do this, I also had to cut back the Audi CIS-E injector holder to unshroud
> the new injectors. The net result is that the injectors now spray into the
> intake port with no shrouded blockage! Remember, these injectors can be
> placed from 1 to 4 inches back from the intake port. I've tested the injector
> spray pattern at 35 psi and 50 psi, and the cone just fills the intake port
> right before the valve guide. Good!
> 
> So far then, I am able to use the Audi manifold, reasonable injectors, add
> the diesel pan, etc, etc. etc. But two other bonus points. I can use the more
> efficient Audi crankcase ventilation system, and the throttle port is now on
> the flywheel side of the engine. Well, I have the pan off and the rod shank
> looks more robust that the RV, but can't compare it to the ABA, as I haven't
> done an internal on one of those. Went to take it to the balancing shop and
> was told to go home. The MOIC (Machinist Owner in Charge) told me that these
> were already nearly perfect from the factory. He was willing to take my
> money, but said that the balancing would only be effective for continuous
> operation over 7200 rpm! We parted friends and I gave him the head for
> dress-up work. To be reclaimed on Monday.
> 
> At this point its time to go to the turbo part of the tale. For years I had
> toyed with the idea of building a low boost, high compression turbo.
> Originally, I wanted to take the exhaust, intake and turbo from a 1.6L TD
> Quantum engine, adjust the waste gate to 4 psi max, and pickup both power and
> torque. As to my motives 1) There is my story of finishing my son's Porsche
> 944 turbo, and finding myself crushed back into the seat and accelerating to
> more than 120 at 2 in the morning on the Foothill (210) freeway! Later we
> would take it to 142 on the Palmdale corridor. Bet there were lots of donut
> stains on CHP uniforms that morning! Oh yeh, the point: the car was drivable
> at low rpm but when boost came on, it turned on like a rocket. 2). Rode in a
> friends Saab 900 turbo in 1989. I owned the 16 V 2.0L 9000 at the time. Wow.
> You would swear (sorry) that that thing had a classic V8 underhood. No turbo
> turn-on just hard hauling from the bottom to the top of the band. 3. Rode in
> a well tuned rabbit with the 8.5 CR engine, then in a rabbit with 10:1 CR.
> The difference was low speed torque. Gobs more in the high CR car.
> 
> The typical approach of the turboheads is to cut the compression to around 8
> to 8.5 to 1, then boost to power (12 to 15 psi), or till the sweet smell of
> an aluminum plasma permeates the passenger compartment. So, I planned stock
> high compression for low end torque and modest boost for genteel acceleration
> as appropriate.
> 
> Then I began to search over the issue of how much boost was reliably achieved
> by hobbyist turbocharged VW 2.0L motors. The answer is that with knock sensor
> engines and premium fuel, the consensus was 8 psi. 8 psi! More than I needed
> and at the stock 10.5:1 compression ratio. Now this was for a set of ABA
> engines. There is one significant difference between the 3A and the ABA
> engine. Rod length. Lots of discussion (complete with the strident pounding
> of hairy chests) as to which is better. Well, it is said in the turbo
> literature that the most important figure of merit on a turbocharged engine
> is the rod - to - bore ratio. Ideal is supposed to be 1.75. The ratio for the
> ABA is 1.66, while that for the 3A is 1.72.  So the ABA with longer rods
> (same displacement) is a bit more of a torquer, while the 3A will have a
> better top end.
> 
> Unfortunately, the diesel turbo is not the correct choice and could be
> readily damaged in the gas engine application. The diesel has a low
> temperature exhaust (remember efficiency) and the gas engine is considerably
> hotter. The increased energy (flow and Temperature) can drive the turbo into
> a surge condition. Possible self destruction or at least manifold cracking
> (temperature runaway).
> 
> Then I discovered the Saab turbo story in technical detail. The Saab 900
> turbo engines through 1990 are 2.0 L with very similar torque and power
> curves for the NA 8 V cars as compared to the VAG 2.0L motors. Therefore my
> first thought was off to the boneyard and pickup a properly sized turbo for
> peanuts. Actually came to $100. Then while stripping this '86 900T 16V motor,
> I realized that the injectors were the same type as the digifant, the fuel
> pressure regulator, etc., etc. Took em all. Then studying the Saab approach,
> I realized that this was just what I was after.
> 
> Saab uses a high compression engine with very good engine management (Bosch
> hot wire LH-Jetronic) and an independent system to control the turbo! Instead
> of the classic approach of setting up the wastegate to dump at a particular
> pressure, or setting it up for manual boost control (invites the Aluminum
> plasma together with loud metallic noises), Saab electronically controls
> boost with a separate analog computer. The waste gate is set up for a
> baseline dump (if the full control is malfunctioning) at 4 to 5 psi. Then the
> Saab APC computer monitors engine rpm and a knock sensor. The APC (Automatic
> Performance Control) controls the wastegate operation through a solenoid and
> applies the maximum boost just shy of detonation. For the Saabs, this value
> is set at 10 psi. In other words, this system keeps the boost pressure below
> detonation levels always. Back I went for the APC box, the LH-Jetronic
> computer, ignition control computer, all switches, senders, fuel fittings,
> ignition goodies, etc.
> 
> So, the plan: Audi 3A as described. Digifant fuel rail to feed Saab injectors
> in the formerly CIS-E intake manifold. Adjustable fuel pressure regulator
> with vacuum and boost referenced to dial in the proper pressure. Custom
> exhaust manifold with T-3 flange pointing down at the flywheel end of motor
> (bigger duplicate of the quantum TD manifold with proper flange). Liquid to
> air intercooler between turbo output and the intake (recirculating pump, VW
> Golf coolant reservoir mounted  at frame on wheel well, with Mazda RX-7 oil
> cooler mounted below current radiator acting as heat exchanger, liquid level
> sensor in coolant tank. Recovery tank in engine compartment and temp sender
> in circuit hose line). Saab hot wire air mass meter input to turbo, fed by
> cooled K&N intake system in driver's side vent - previously described). Full
> Saab engine control electronics. Remote oil filter and Mazda RX-7 oil cooler,
> with MECCA Accusump oil lubricator - previously described. Diesel pan, mount,
> as before.
> 
> Only major stumbling block is duplicating the Saab vacuum advance only Hall
> triggered distributor.
> 
> So, to summarize the summary. This is planned to be a 2.0 turbo that fits
> under the engine cover. All components are western European. Built for high
> reliability. Anticipated power : 160 hp at 5500 rpm and 188 LB-ft at 3000
> rpm. This is probably the limit for the clutch and transmission package in
> the Vanagon.
> 
> Good Night,
> 
> Frank Grunthaner

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