more supercharger talk

[Rabbit on Roids]

ok, let me rephrase it then. short of building a custom engine mount, you can not get a VNT to fit on a Mk2.

[ryanp]

On this very site (in the TDI section) i made this post:



This is a GT1749VA turbo, clears the mk2/3 mounts perfectly! It's for sale BTW!

[truckinwagen]

I just opened up the G60 and found out that it has been rebuilt very recently(probably less than 1000 miles ago)
Score!

I m going to keep and use the G60 now that I dont have to spend $400 on rebuild parts.

I think I will make a bypass for idle and when the turbo spools, but I think I will use a throttle body that opens the boost piping post supercharger to the boost piping pre supercharger.

that way at idle the boost will recirculate through the supercharger, there will be some load form the internal compressing of the supercharger, but not too much(a few HP at most)

and when the turbo starts to boost the throttle body will open(by an internal wastegate can) and allow the turbo to blow past the supercharger.

it will be similar to the VNT controllers with a cable from the throttle and a WG can actuating the bypass valve(throttle body)

[truckinwagen]

should be happening fairly soon.

the only thing I am unsure of is whether I can get the throttle body to seal well enough to hold boost post supercharger.

throttle bodies are designed to "leak" when closed to allow idle, I know I can block off the idle bypass, but I don't know if I can get a good seal with the butterfly in the body.

I need a valve that I can control with a cable(from the throttle) and with boost(I was thinking of using a boost can)
the throttle body seems like a good idea, but if I cant get it to seal properly does anyone have any other ideas about what I could use?

[Rabbit on Roids]

hmm, maybe something like the stock recirc system that they came with? they work fine.

[truckinwagen]

if I was going to use an eaton that would be great, but as I stated a few posts ago, the G60 has already been rebuilt and I am going to use it.

as the G60 has no recirculation system I need to come up with something to act like the eaton's.

I could simply put a one way valve in so that the turbo would be able to bypass the supercharger once it is pushing more boost, but that would not cut the boost at idle.

[lord_verminaard]

G60's do have a recirculation system, they are external and mounted on the throttle body.  They do work pretty well.

Brendan

[Rabbit on Roids]

yea, thats what i was talking about, the G60's have a recirc system right before the throttle body. its that big pipe that runs from the t-body back to the intake of the G lader.

[truckinwagen]

the problem with the  G60 recirc is that it is part of the throttle body, and when the recirc is open the throttle body is closed.

I just want to keep from boosting at idle, I dont want to close off the intake at the same time.
One might be modified to remove the throttle plate and keep the bypass, but I would need to find a G60 throttle body.

and I would still need to figure out a bypass for the turbo, but I am thinking that a pool check valve might do the trick nicely.

[truckinwagen]

looks like the of the local guys has a G60 throttle body, so I will see if I can modify it to work.

next is to figure out how to get the throttle cable attached(might have use the Gasser valve cover)

[LeonardoL]

Coming a bit late in this topic, but here goes my $ 0.02: for a 1.6 diesel engine you could use a SC as little as the Eaton M24, which would run nicely and fit better in any corner under the hood.

As said before, the horsepower needed to run your SC is directly proportional to the amout of air your engine will be consuming. For instance: if your engine is breathing 26L by second (1.6L @ 2000rpm) and your SC is pushing 52L by second, you would have almost 1kg/cm2 of pressure (considering no thermal losses). The same thing in a 1.9L engine would be like 0.6kg/cm2 (no thermal losses again).

It is the same amount of air, but at different pressures. And in the two cases, the same SC would be consuming different HP. IOW: to really know how much HP would be needed, you should check the compressor map for your SC, and make some approximations from the data available.

Cheers,
Leonardo

[truckinwagen]

yeah, the little 1.6 does not consume much air.

I have decided to use the G60 as I just found out that it has been rebuilt recently and I have it in my grubby little hands already.

it is also sized appropriately(to give 11PSI to a 1.8L) so I dont need to worry about getting something too big.

I found a G60 throttle body to use as a bypass locally for $40, I am thinking all I need to do is remove the butterfly's from the throttle body portion(leaving the center rods) and figure out how to hook up the second throttle cable.

-Owen

[truckinwagen]

well, I picked up the G60 throttle body yesterday, it will bolt right up to the manifold I will be using!



the bypass:

closes as the throttle plate opens, so it bleeds boost off at idle and slowly forces more of the boost in until at full throttle it is closed, forcing 100% of the boost into the motor.

the only problem is that it has a throttle plate, not what a diesel needs


but that is easily dealt with(four phillips screws!)


now it looks better!


the G60 has a two sided intake, one for the air filter and one for the boost return, I plan on using the stock return location(maybe even find a set of the stock return piping)

as for the throttle cable issue, I plan on pulling the cable pull attachment from another throttle body and piggybacking it on the G60 one, so as the throttle body is opened by one cable it will pull on another, which will be attached to the injection pump.

the G60 throttle body also has an idle switch and a WOT switch, I plan on hooking the WOT switch to my water/meth injection system.

as for the idle switch, I am not sure, I was kinda thinking I could hook it up to the radiator fan, so when I am sitting in traffic(basically the only time the radiator fan is ever needed) the fan would come on, but as soon as I get back on the throttle and start moving it would turn off.

I am getting excited! I am going to check the motor to be rebuilt for all of this tomorrow and then start ordering parts!

-Owen

[truckinwagen]

I also picked up a EGT gauge and controller that will turn on the water/meth when my EGT's climb past a certain point.

[tindias]

Is your 1.6 TD or NA? You might run into some issues with cooling if you are boosting a NA motor.  Personally I think you would be better off using a 1.9 TDI motor instead.