Holden 202 straight gas + turbo conversion

[Mr Whippy]

Hi to all BUGA members.

I thought you all might be interested in my  turbo + straight gas conversion which I did to my camper "Mr whippy" late last year and have been fettling to get perfect ever since.

Allmost there just need to fit an engine oil cooler and I reckon I'll be  onto the next phase, the cab bodywork!

Firstly I'll give a explanation as to why I went for this option.

The camper allready had a freshly rebuilt 202 in place of it's original 186 red motor. The motor ran well, had a nice HEI ignition but apart from that was stock as a rock. Was slow (top speed nudging 105kph) and thirsty as hell on petrol. I really wanted to do a straight gas conversion, as I have had some experience with these old holden sixs running dual fuel set ups and they were allways a compromise in terms of tuning. I just didn't want to lose any more power changing over to LPG.
I had done some research on gas and it was obvious that running LPG with its super high octane rating and some form of supercharging would work really well together. Enter the turbo idea.
I looked around on the internet and found  the 202 had been done turboed many times before, in particular the Strata kits supplied by garrett in the early eighties. Apart from some manifold sealing issues and the obvious problem of keeping it cool, the stock 202 didn't seem to mind a little bit of boost in its stock form.

So the first thing was to find a gas convertor who would be willing to take on the task of fitting the gas system. I rang around and copped a fair bit of flack from various gas installers that I presented my idea to, from the "why would you want to fit a straight lpg system to camper, what happens if you run out of gas in BFN?" to "Mate your stupid to think that engine will last 5 seconds with a turbo on it".
Finally i called these guys http://www.ragelpg.com.au/index.htm, told them what I wanted to do and the answer was a simple "Yeah, we can do that, no worries". I took the camper over to them so we could sort out issues like where to place the gas tanks etc and a date was arranged as to when I would have the van ready for them to do their bit and I was away.

Okay so I had now found a shop to do the gas side of the conversion, I needed to work out how I was going to turbo the old lump. I knew from my chat to the rage lpg guy that although Gas research didnt state it on their website, their gold series gas mixer was suitable for blow through turbo setups. Seeing as a really wanted to avoid a draw through system as (a). compressed LPG and air is not something that I wanted running throught a turbo compressor, much better to keep it just air in that part of the system and add gas down stream close as possible to the intake. and (b) Draw through turbochargers aren't that common anymore as they need a special carbon face seal in the compressor to stop oil being sucking out of the bearing. So a Gas research mixer in a blow through configuration it was.

Here is the mixer


The adaptor from the mixer to the stock stromberg manifold


Next was to work out what turbo I needed. I had read that Garrett's range of ball bearing turbos were really durable as they have a water cooled centre and the ball bearing setup spooled up really quickly which meant little or no lag. As I am after bulk torque low down in the rev range I knew that the turbo wouldn't need to be very big. I called the guys at MTQ in perth http://www.mtqes.com.au/index.php, told them what I wanted to do and they advised me that the Garrett GT2860R would be ideal for what I wanted and did a nice deal on the price

So now I had the turbo



Well thats all I can be bothered with today so thanks for reading so far and I will post more later:
to be continued

[Bas NZ]

Interestig, part 2 please.

[John Abbott]

Hey Mister Whippy....some real thought has gone into your set up And isnt it nice to find a workshop that doesnt think your a looney when you want something a bit out of the ordinary ?
Looking forward to the next installment...

[Mr Whippy]

Thanks for your replies fellas. Thats right John the blokes down at R.A.G.E made this heaps easier with their advice and I  would recommend them to anyone who wants to do a gas conversion  that is a little different.
As I said in the first post  I started this last september, so a lot of this thread is retrospective. I had taken some great pics of the build but I lost the camera soon after (I think my little girl put it in the bin, she likes to tidy up around the house and probably thought she was just helping) Hence most of the pictures have been taken recently, but I am going to cover as much detail as I can.

So now I had all the main bits for the turbo conversion but no exhaust manifold. I had an old cast iron job from my uncles HR so I thought I would have a go at modifying it by cutting off the outlet flange and welding on a garrett T3 flange which is the same size as the GT28 turbo.  The original outlet came out the bottom and I wanted it to come out on the side. So I cut off the outlet, trimmed out the side to fit the T3 flange and made a plate out of 6mmx50 flat bar to cover over the hole in the bottom where the old outlet was. I bought a packet of cast iron welding rods and welded it all up being careful to preheat the manifold and to peen the weld  each time with a chipping hammer. I even got it cracked tested when I got the mounting faces milled flat. Yet she still cracked after only a  thousand kays use!

Here are a couple of images of the modified cast manifold




I really feel that modifying the cast manifold was a waste of time. A better way if anyone really wants to use it would be to make a j pipe and bolt it to the original manifold outlet.
Second time around  I just made a log manifold out of some 1.1/2" steam pipe, 6x 90 degree steampipe bends, 2x 45 degree bends, an T3 turbo flange and a DIY red motor header flange set. It was a lot easier than I thought it would be as you can weld it all up with a MIG. Plus I reckon it will flow better too.

Here are some images of the new manifold










I used an old block and cylinder head as a jig to make the manifold. I Bolted the old manifold to the block and sprayed around it onto the block with white marker paint so I knew where to run the new manifold as I had  an outline of it.
Plus it was handy having the engine jig  as I could measure off the engine in the bedford using references off the casting, and apply the measurements to the jig block to get the turbo just where I wanted it. The turbo was 10-15mm too high on the old manifold as it was so close to the passenger floor that it was burning the paint off!
The new manifold is perfect.