Supercharged Stock 1600 DP

[Boardpaul]

I like hw quick this has turned round as well.

[T-34]

Yes I was getting a bit worried about the emissions carby and having visions of having to junk it in favour of something else. The turning point was really finding this thread - http://www.thesamba.com/vw/forum/viewto ... sc&start=0 and getting the LM-2.

I'm glad I took the plunge with purchasing the LM-2. The upshot is that I won't be getting the carbs set up on the dyno as I am pretty happy where it is, in effect it's saved me quite a bit of dyno time - in fact it's probably paid for itself already.

[damo99]

have a look at these 3 videos of an amr500 on a vw 1835, 1600 and a 1300
http://www.youtube.com/watch?v=7X3SlwW0Juo
http://www.youtube.com/watch?v=cYzvJyg2HeM
http://www.youtube.com/watch?v=ztQZ_tAyTlw
and also this in the samba
http://www.thesamba.com/vw/forum/viewtopic.php?t=516458

[Corysvdub]

Thanks Corysvdub.

EFI and Turbo'd Type3! Do you have any links to your car? Was thinking of doing this to my Type 34 - Stock type 3 hardware with megasquirt and a Garret T3.

Here it is
http://www.shoptalkforums.com/viewtopic ... 3&t=138825

[T-34]

Cool setup there Corysvdub. Love the way that the intercooler fits in where the air filter used to be.

damo99. I've seen all of these except the 1835. I'm actually surprised (well both surprised and perhaps not) that he is using an AMR500 on an 1835. Just goes to show that the little AMR500 has more ommph than most people give it credit for.

I opened up the idle jets a little more and did a bit more testing today. Was surprised that idle AFR was a little leaner than how I left it last night. Go figure. Not too sure why this is, maybe something to do with engine temps? I took the bus for a run up the freeway. At the start is a massive hill. Normally I cannot get up this in top gear, I have to change down to third and labour it at about 60kph. Well today it was no issue to go up it in top at 80kph. Unfortunately I also noticed that it was running lean @ 17.ish

This evening I increased the mains from 1.6 to 1.7 and immediately noticed a massive difference. It pulls much much harder. I could easily keep up with normal traffic, even from a standstill (although given the super low ratio of 1st gear on an early bay it probably sounded like I was wringing the nuts out of it). Still a bit lean on heavy load at wider throttle (15's) so will take the mains up another size to try and even this out.

I think the large airs I had to use to bring the transition down has leaned the mains out a fair bit. This wasn't really as noticeable when not on full load but was easily visible when going up hill.

I recon that I am just touching 5psi now as the gauge I am using has a warning light that comes on below 5 psi - I've now seen this flick off a few times. Prior to increasing the mains I would have sworn that I was only seeing 4psi. Guess it's liking having more fuel.

Engine temps were down around the 170 mark today, the cooler plugs have definitely help bring the temps down. I also went out and bought some fittings so that I can install the oil cooler, will try to get this done this weekend along with a service.

Tomorrow I will try opening up the mains to 1.80 and see what happens. It feels like there is a little more power to come that is being held back due to the mains being a little lean, guess tomorrow I will find out.

Overall I am pretty stoked, especially being able to keep up with traffic. It's fully loaded with camping gear and is no spring chicken. Best thing was being able to go up the hill at the start of the freeway in top gear pulling 80k's. If nothing else I'm pretty happy that I have achieved what I set out to do - turn the stock 1600 into something a little more drivable.

Mick.

[andy198712]

Very cool! I keep meaning to get a wideband, yours seems to have helped alot!

[Buggin_74]

I'm going to go ahead and order a pair of 28mm venturis.

Hi Mick, that just jogged my memory, I keep forgetting all these small details, it was about 6 years ago I built that blower setup
I remember with mine I had to spin up some new 28mm vents as the 30something vents the DHLA came with were too much even for the 1776.

I'll drag it out over easter and check the jet sizes for you

[T-34]

I'm going to go ahead and order a pair of 28mm venturis.

Hi Mick, that just jogged my memory, I keep forgetting all these small details, it was about 6 years ago I built that blower setup
I remember with mine I had to spin up some new 28mm vents as the 30something vents the DHLA came with were too much even for the 1776.

I'll drag it out over easter and check the jet sizes for you

Thanks Joel. I'd be very interested to see what you had in there.

[T-34]

Been driving it about a bit. After opening the mains up the hesitation has reduced and there is more power but it's still a little lean on WOT and a heavy load. Bus drives great but still got some tweaking to do to make it perfect.

I upped the boost a little by fitting a 70mm pulley. I was expecting the boost to rise to somewhere in the 7/8 psi range but it only rose to about 6. I then turned down the original 60mm pulley so that the vee profile was correct (well as good as I could get it) and fitted that but found that it was still generating about the same boost, but this time with lots of audible belt slip so I changed back to the previous pulley.

I think I might need to come down a size on the airs to stop it leaning out under WOT under heavy load. I also need to bring the idles down a size as the increases to the mains has made them a little richer (I think this is due to the connection between the mains and idles)

I think I might have reached the limitation of the current belt configuration. It seems that 5/6 psi is the limit that I can generate before it slips. This means that to get the 7/8 psi I am aiming for I will need to have a rethink about how to run the belt. Looks like it's time to design version 2

Mick.

[gearheadgreg]

Great progress, man. Keep it up. Good inspiration for me (who's Bus has been sitting since he bought it a few years ago!)

[T-34]

Been playing about with jetting again. Had a bit of correspondence through the samba wideband thread and opened up the idle air bleed back up to it's original setting. Before opening it up I initially drilled it out to 1.5mm and found that the bus was running the best it had done so far - albeit still with a minor bit of hesitation. I've now opened it up to 1.8mm and it seems to be a massive step backwards.

I've currently got the main airs at 2.2 and the mains at 2 trying to close up the 'hole' between the idles and the mains (the cause of the hesitation that I am seeing) but the mains are now too lean. I will open them up more and see how this effects things.

I get the feeling that it's not the right thing to do but will follow this line of experimentation through to it's logical conclusion. I also have a feeling that the real issue is the emulsions so will look to get a set or two.

I also had another belt issue, this time it's simply worn to the point that it will not stay on. After throwing th ebelt twice on the way to work this morning I had to put a new belt on. I have a feeling that this may be due to the smaller pulley. Ever since fitting the 70mm pulley I have noticed a lot of rubber dust indicating belt wear. I cannot help but think that the belt is slipping - this being the reason that I did not see the increase in boost that I expected, Whilst this slip is not enough to be audible, it is enough to have gradually worn the belt.

So far, from my experience I would say that the 80mm pulley running at 4/5 psi is the maximum / optimum that you can get using the stock width belt in a single belt configuration. If I am to look at getting my goal of 7/8psi I am going to have to look at changing the belts out to something different.

I looked into the WBX pulleys, unfortunately this is not really a viable option for the kit as the WBX pulley does not incorporate an oil slinger. Instead it uses a proper oil seal in the case. This means that to get it to work, either an oil slinger has to be machined into the pulley or a seal needs to be fitted to the case. Whilst there are such seals available, they are not an easy thing to fit and adds additional complexity to the kit, plus finding a reliable source of pulleys is not an easy task. I think that this is still a good option for someone making a one off but for me I will put this option on the back burner for the time being.

So next step is to take a look down the local u-pull-it to see what I can find in the way of suitable pulleys. It looks like I will need to use multi-groove pulleys to help stop the slip.

Ultimately I will need to get pulleys manufactured for the crank and alternator and use the stock pulley that comes on the charger. This is much like the serpentine belt kits that you can get from EMPI / elsewhere. Unfortunately if I have to buy these in I think that the cost of the kit will be a little too expensive.

Will let you know how I get on.

[T-34]

Been looking at the differences between the emulsion tubes. The Des Hammill book lists in order from lean to rich the applicable range of emulsion tubes as 7772.10 / 8 / 2 / 1 / 14 / 5 / 7 / 6

I have 7772.11's fitted to mine - not even on the list.

it was mentioned by vakot110 earlier that they changed out to 7772.6's to get their setup dialled in. John over on the samba thread mentioned that 7772.7's were only for big V8's or centre mount carburettor setups and I think that this info is the key. I think that the emulsion tubes that I am using are too lean through the range (not sure that I could get any more holes in them if I wanted to).

Looking at the useful image above I'm trying to figure out what I can do to my .11's to turn them into something else whilst I wait for some new tubes to arrive. I think that I could turn my 11's into 5's relatively easily by soldering a few holes up but unfortunately there is no image of a 7.

Would be good to get some more info on the technical differences or even better some engineering drawings.

Can anyone help?

[T-34]

Actually I misread what had been posted over on the samba - it was an F7 not .7

Phah, and I thought I was on to something.

[andy198712]

All very interesting keep it up!

[T-34]

After doing a bit of research it seems that I cannot (should not) swap the emulsions over to .6s The main reason being that it changes the operation of the carb. I guess that in one way this would be beneficial but I'm determined to get the carb running the way that it should with the 'emissions' functions intact.

After playing about with various configurations I've ordered another set of chokes - this time 24mm. Spoke to Dave at recarb here in Australia - He's been supplying me with my Dellorto parts. He seems to think that the airspeed is simply too low, this is also echoed by the guys over at thesamba. So I've ordered the smallest chokes I can get.

Chokes probably won't be here until Friday.

Made a trip to the local u-pull-it today to take a look at pulleys. Managed to pick up a couple of ribbed pulleys to test with. Also negotiating with some suppliers for serpentine systems to see if I can get a more reasonable price.

In the mean time here's some interesting reading on emissions model dellortos...

Type 3 DHLA40F-G-H-N-R-S models. These are called emission completely different to the DCOE science, but noone really understands them and tries always to tune them like the early models. These differ because they have more progression holes and use the idle jet to feed most of the cruise phase and low rpm/low TP area of the engine AT ALL TIMES when the main jet isn’t in operation completely automatically no jetting needed. The idle jet has a very large fixed 2.2mm air feed, you cannot tune this phase of the carburetor for length like the others, but here lays the secrets….

The idle jet doesn’t feed from the float bowl, it feeds directly from the main jet stack, what happens after this is what gives these Dell’Ortos the sweetest road behaviour (what 25years of research came up with and not just for emissions) and dead easy tuning, you see when the main jet starts to emulsify fuel in the tube, the idle jet is feeding from it, so the gassy airy fuel shuts down the idle jet and sucks backwards yes BACKWARDS through the idle!! using every drip of fuel efficiently without ANY waste in circuit cross over where one is going after the other…this happens the moment the main jet fires, so there is NO need at all to tune the length of the progression and idle phase. This is pure magic they are automatically calibrated, you simply keep the idle jet above 59 up to 62 and not make the mistake of fitting numbers suited to the early DHLA or DCOE - with this simple technique you can tune anything from a 1300 to a 2000cc without really doing anything. The emulsion tubes in these carbs are always 8-10-11 and have to stay that way - which are really rich and have a hole straight down with loads of air holes, these atomise the fuel to an massive degree, also they have to be used cause the idle jet will not run correctly using the DHLA40-E type tubes (1-6-7-5) as the idle jet needs these airy tubes to function and cut out as designed…Usually people ram the DHLA40 idle holders with air holes in these carbs add the 1-6-5-7 style tubes and wonder why its a massive lean spot off idle, cause they missed the point completely!…These carbs use a .3 vent which has a very small signal tube to the main jet stack, this is because the holey tubes are basically ready to go from about 1250rpm (on my car using an 8tube 1 vent it was on the mains at 1250rpm!) so the holey tubes need holding back with a signal killing venturi…These carbs are wicked if you want bolt on power, they tune themselves!