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Fri Oct 28, 2011 10:59 am

I'm sure some will appreciate this project and others will roll their eyes. Well...that's what makes it fun :D

After countless hours of researching engine conversions, I decided to stick with the WBX. Here's a basic rundown of what I will be doing:

1. WBX 2.1 with upgraded connecting rods and bolts from Rocky Jennings. Other improvements will be made as I go along. Possibly larger pistons. I will be consulting with Rocky and Chris (tencent) on their thoughts as I work through it.

2. Digifant is going away and will be replaced with a Megasquirt EMS to control both spark and fuel.

3. Turbocharger running mild boost settings with intercooler and water injection.

This is just the beginning. I'm open to ideas, thoughts, and suggestions. I'm not open to the idea of scrapping the project for a 1.8, Subaru, or Zetec :wink:

Here's a picture of the engine I picked up for the project. Removed from a 1990 VW Carat that was very well maintained:

Fri Oct 28, 2011 11:01 am

Yes! Turbo it!

Fri Oct 28, 2011 11:09 am

Hell yes! I'll be watching 8)

Fri Oct 28, 2011 11:12 am

A few people on here have put a turbo on their WBXers, hopefully they'll chime in. If I remember correctly it seems like most of them had tuning issues, but hopefully the megasquirt will be able to handle it if you get it dialed in correctly.

Good luck!

Fri Oct 28, 2011 11:15 am

I've been seriously contemplating this exact approach, myself. What's your proposed strategy for intercooling?

I assume you've seen the thread about the guy who swapped over the turbo and engine management from a 740 Volvo, right?

Fri Oct 28, 2011 11:17 am

I knew it went to a good home.
Jeff

Fri Oct 28, 2011 11:32 am

Subscribed .

I think stand alone fuel/spark would be a +/- 10 hp boost for any wbx.

Does the megasquirt use crank fired ignition?

Fri Oct 28, 2011 11:38 am

Anyway to add piston oil squirters? Looking at pics of them in other engines they aren't compicated.

Fri Oct 28, 2011 12:19 pm

I'll be watching too, sounds good and good luck to you.

Fri Oct 28, 2011 12:35 pm

You can use stock dizzy pickup for crank triggering.
Would be nice to use a coil pack setup like suby too.
I would put a front mount intercooler on it and run the tubes front to rear.
There is Corvette turbo setup with long intercooler pipes and it improves the cooling.

Megasquirt is fun and baseline maps are easy to setup with innovative wideband O2.

Fri Oct 28, 2011 12:39 pm

The megasquirt can use a trigger wheel on a pulley or they now have what is a trigger wheel inside the distro housing. You can use coil on plug or edis, or two coil packs with wasted spark. You can do what you want.

It will read both tps and manifold pressure which will be usefull when you turbo.

Good luck this sounds awesome.

Fri Oct 28, 2011 12:42 pm

Fri Oct 28, 2011 2:41 pm

You might not need the Megasquirt, although it'd be cool. :) Higher fuel pressure(and/or injectors), adjusted MAF, and a spark retard box might be all you need.

What compression ratio are you aiming for?

Fri Oct 28, 2011 2:43 pm

Thanks for the encouragement!

The first step is building up the engine slowly, retaining the stock compression ratio, which will work well for my mildly boosted engine. I want to gather as much information possible to start off with a strong/reliable base. As far as the baseline goes, here's some items needed to be addressed:

1. Besides getting rid of the stock stretch bolts, what are the other weak areas to improve on while I've got it torn apart.

2. Camshaft. Will I benefit much from a modified cam in a boosted engine? I do want to retain hydraulic lifters.

3. Ceramic coated heads/pistons. Factoring in that I will have water injection, which will reduce cylinder temperatures and carbon buildup, will there be a reason to ceramic coat any of the internals? I'm not sure if I need to be concerned with corrosion issues with AMC heads and regular maintenance of the cooling system.

4. Valves. Will I benefit much from valve modifcations with a boosted engine?

This project has a long ways to go, so please be patient! I will document the process as I go along.

Again, all questions, suggestions, comments are encouraged.

Scott

Fri Oct 28, 2011 2:55 pm

presslab wrote: You might not need the Megasquirt, although it'd be cool. :) Higher fuel pressure(and/or injectors), adjusted MAF, and a spark retard box might be all you need.

What compression ratio are you aiming for?

Presslab, I do agree that it may not be necessary, but I like the fact that I will have complete control of the engine managment system to match my application, versus trying to take the stock system and make it work with my application.

I believe there will be a large difference in tunability and efficiency using the Megasquirt system, intead of stock.

I plan on retaining the stock compression ratio of the MV 2.1

Fri Oct 28, 2011 2:57 pm

Cool, megasquirt would be awesome....nice and clean.

where in washington are ya?

Ole rocky is in my backyard, close anyways.

Fri Oct 28, 2011 3:02 pm

purplepeopleeater wrote: Cool, megasquirt would be awesome....nice and clean.

where in washington are ya?

Ole rocky is in my backyard, close anyways.

Let's see...I'm all over Western WA :D In West Seattle (my actual home) and Bellingham (my hangar hotel).

I plan in the near future setting up a meet and greet at Rocky's to get some of my questions answered.

Fri Oct 28, 2011 5:53 pm

Hey Scott,

I think its great that you are going to tackle this one. A turbo WBX is something many have contemplated over the years, but so far very few have put the time into actually doing it.

I would look closely at the setup that JoeVW has shown on here. He used the components from a Volvo 740/760 turbo and came up with impressive results. His build will give you the best answers as to whether a stock cam, and stock heads, pistons are suitable. (In my opinion all three are fine.) He used the stock Volvo Bosch L Jetronic system and apparently it worked very well. I understand your desire for laptop tuneability so Megasquirt would certainly be an affordable way to attain this. A couple thoughts I have:

1. The 2.1 pistons have an 8.8:1 CR. These will be fine for a mild turbo. There are a couple of affordable choices for larger pistons that would give you a full 2200cc. AA Piston 95.5mm and QSC 96mm. The QSCs if used with stock rods will lower the CR a bit and would allow higher boost. However, I think it makes a lot of sense to stay with a stock bore so that the sealing rings at the tops of the cylinders will be as wide as possible.

2. Unless you are going with really low boost, it would be a good idea to fit the engine with a knock sensor so that the optimal timing vs detonation calibrations are achieved. Placement of a ks on a wet sleeve engine is problematic and there are very few OEM precedents set down. Alfa Romeo V6s are wet sleeve engines. It would be interesting to see where they placed their knock sensor.

3. I don't think there is any way to use piston spray oilers with a wbx since the oil pressure characteristics of these engines are less than ideal. I don't have any proof of this or anecdotal evidence, but the idle oil pressure of these engines is very marginal even without having to supply additonal oil volume to four oil squirters.

4. The stock valve sizes are very decent for an engine of this displacement. With some port work from Rocky the flow should be excellent with a turbo.

Anyway, just some thoughts I thought I'd bring up. I am very much in support of this idea. It's true that there are many conversion choices that would produce a similar result, but there is something I really like about the good old WBX. It would be cool to have one with some real power and torque.

David

Fri Oct 28, 2011 6:58 pm

Cheers to SL12572:

I have my SVX engine still sitting on my engine stand at home and so my interest in the turbo WBX engine is semi-academic. I do have a couple spare westies besides my syncro westy that I like to play with.

I have often thought how good it would be to turbocharge the WBX given that no other fitment issues would arise, and that there is a wealth of existing knowledge about the peculiarities of the WBX.

I turbocharged a Toyota 22RE engine years ago using Megasquirt. It was a very fun and rewarding project. For the WBX, it is actually a very practical solution to the underpowered nature of the WBX.

So here are my observations and hints:

1. For choice of turbocharger: I have an Audi URS4 with the 2.2 litre 5-cylinder turbo engine which, with upgraded turbo, injectors, chip, exhaust, etc., is a very fun drive. Many owners have upgraded these cars with the Audi RS2 turbo, meaning there are LOTS of the orignal stock S4 spec K24 turbos available used. That turbo on the stock S4 engine (230 HP stock) made boost from 1,800 RPM. It started to run out of breath at 6,000 RPM (but still rev and make power to the 7,000 rpm redline.) It would be an ideal turbo for the WBX since it is 2.1 litres and boost be available from 1,800. It is also a very robust design with a separate waste gate. Check out Audifans Marketplace for used turbos:

http://www.audifans.com/marketplace/browse.php

2. Don't confuse the S4 K24 design with the different A/R K24 turbos Audi installed on some other Audi models. Also note the the K26 turbo used on the old Audi 5000 turbo engine is laggy and really only makes boost from around 2,500 rpm - - not good for the WBX.

3. Don't worry about lowering compression. Worry instead about getting the best squish/quench characteristics you can. Run the tightest deck height you feel comfortable with. If you consistently (but not always) use water injection, then you will never get significant carbon buildup in the combustion chamber nor on the pistons and you can even go as tight as a 0.030" deck height.

4. J&S Safeguard is an excellent stand-alone knock control system that can be used on any engine running any engine management system except wasted spark. It is cylinder-selective, which is why wasted spark won't allow it to be effective. Here's a link to their website:

http://www.jandssafeguard.com/

5. The beauty of the J&S is that the sensitivity can be adjusted easily. It will not require an engineering degree to place the knock sensor correctly, although you will be the guinea pig if you take up the challenge. Many OEMs place the sensors closer to the crank end of the cylinder, presumably to avoid false readings from valve-train noise. In the WBX, you might have to run two knock sensors.

6. Ceramic coatings are great, but I don't think they assist in a turbo engine. Remember that they can impair piston cooling. No OEMs I know of (although I am ready to hear about those that do) use ceramics in their turbo engines. Maybe more importantly, I would be concerned about chips of ceramic material destoying the turbine section.

7. There are quite a few people who have done high performance WBX turbo setups running MegaSquirt and who have shared their experience and setups on Megasquirt's "It Runs" forum. Base maps are available.

8. A mild performance cam would be good, but nothing with long duration or much overlap. Basically, I have thought, the WBX just needs a little cam help in revving comfortably past 4,000 rpm. Ratio rockers and a bit more lift than stock with slightly more duration but minimal overlap would be my goals.

9. Since it's boosted, and the air density is far greater, flow concerns are not as critical as in a NA engine. No porting except to clean up the bowls at the bottom of the valve seat would be needed. You would likely want a slightly wider valve seat and a healthy margin on the valves. Inconel or Manley or TRW stainless exhaust valves would probably help longevity.

10. The achilles heel of so many DIY turbo set ups for long-term reliability, I think, is a crappy exhaust system (between the engine and the turbo) that simply cannot withstand the heat and cracks or breaks. Givne the tubing length that the flat WBX mandates, this will be a challenge.

11. An Air-to-water intercooler setup would be ideal given the lack of airflow in the Vanagon engine compartment, but if you don't mind the roar of a fan, an electric fan-cooled intercooler could be a close second.

12. Going to an aftermarket engine management system has one great benefit - - you can get rid of the Air Flow Meter altogether and just use a MAP-based speed/density system, although you would still need an air temp sensor.

13. The turbo set-up would definitely require a more robust oil cooler setup. An air-to-oil system would be best. Those same old Audi turbo cars (including the old 5000 turbos) have a good system that could be grafted onto the WBX fairly easily with the "sandwich" adaptor from the Audi installed in place of the WBX oil cooler.

Fri Oct 28, 2011 8:16 pm

The Volvo turbos can also be a nifty source for the aforementioned oil cooler bits ^

I'm planning to adapt these pieces to my mTDI swap