Supercharged Stock 1600 DP

[yvre]

Thank god for electronic fuel injection.

[T-34]

Thank god for electronic fuel injection.

Where's the fun it that?

[T-34]

Received my dual vac can this morning, but going to hold off from fitting it at the moment as I have a feeling that it mask the hesitation too much.

Hopefully the new 24mm chokes will be here tomorrow.

[T-34]

Hmmnnn. Looking at this vac can it's not going to work.

Applying vac to 'normal' side of can causes lever to pull in (advance)
Applying vac to 'back' side of can causes lever to push out (retard).
Therefore...
Applying boost to 'back' side of can will cause lever to pull in (advance)

Unless I am missing something this is not going to provide retard under boost.

Looks like I am back to my initial thoughts of trying to cancel out the vac with a boost signal.

[T-34]

Okay, after some reading I think I finally got this. Basically the DVDA vac can will work for a blow through setup but not draw through.

The vac line is connected to the 'normal' port - the 'back' port is left to atmosphere.

DVDA vac can will move in both directions from 'normal' port depending if it is seeing vac or pressure (needs quite a lot of pressure on the can that I have to move it outwards tho). With blow through setup normal vac port will see vac at part throttle positions and pressure under boost.

Ahh well, something for the parts bin I guess.

Here's something interesting I found. The HEI ignition units used on GM distributors provide 5 degrees retard if you short one of the pins on the control unit. Some have successfully rigged these units to a pressure switch to provide boost retard.

Interesting fact #2 was that it's possible to make a GM HEI dizzy fit a VW by making a hybrid VW/GM unit. (great for a junk yard project)

Interesting fact #3 is that you can also buy them already converted. http://www.performancedistributors.com/vwdui.htm $259.00 (also seen elsewhere for $660.00!!) Although with these it looks like the controller might be integrated so not sure if you can use the trick of shorting the terminal to provide ignition retard. (might be worth emailing the supplier to find out). This appears to be what the mallory / MSD units are based on.

This is complete overkill for this project so I'm not going to go there but I'd entertain trying to make my own hybrid unit just for shits and giggles. $259 is cheap-as when you consider that the MSD version is about $400 but $20 for a junkyard part is even more appealing.

My setup is working fine with limited mech advance and vac disconnected but I would like to hook the vac back up for better MPG and part throttle (off boost) response. I'm not overly bothered about retard under boost as I am only running a max of 24 degrees and there is no pinking at all, retard under boost seems to be more of a requirement for higher boost applications. I recon what I need to do is figure out how to hook up the vac so that the signal is cancelled out under boost. There were some discussions earlier in the thread about using check valves, but I think what i will take a look into is pneumatic logic gates.

My background is automation and controls systems. I have used pneumatic control systems in the past and think that it might be possible to find something to do the job - basically a small pilot operated changeover valve - if pressure is applied to the pilot port it operates the valve - which indexes the valve to swap between two ports - port vac and manifold vac (boost). This could easily be used to cancel out vac advance on a normal SVDA dizzy or even provide retard under boost if used with an DVDA.

Will take a look and see what I can find.

[T-34]

Well it would appear that I didn't need to be so fancy. All you need is a vac operated petcock valve - used on most bikes / scooters. Plenty on ebay from as little as a few bucks. Will try to find a suitable one and do some testing.

[MarioVelotta]

You just need to throw a Megajolt in this sucker and call it a day! You've already paid for one with the days you have invested

Have you done any more work on the tension setup?

[Clonebug]

X2 on the Megajolt.

In fact...upgrade to a Megasquirt and when you get sick of screwing around with jetting you can just add some FI intakes and injectors and really be done with it.

[T-34]

I agree that adding a megajolt / megasquirt is the simple and easiest solution, but for a budget project is not a viable solution, it makes the kits purchase price too expensive. For my own personal car the cost of putting this together is not a problem, but to provide megajolt / megasquirt as part of the kit it simply is not a cost effective way of adding performance to a stock 1600 - the cost would far exceed the power gain.

For example...

Let say a turn key 2180cc engine costs $5k - it puts out 150bhp - that's 5000/150 = $33 per bhp
lets say that my kit with megasquirt costs $3k it puts out 70bhp - that's 3000/70 - $43 per bhp

With my kit you get much less bang for your buck and still only have a maximum of 70bhp. Chances are that if you use your 1600 as the core the turn key 2180 won't even cost you $5k. My kit only works financially if the overall cost is more appealing than paying the extra for a full engine build. Interestingly, if we take the $33 per bhp as the baseline value, the 70hp that my kit gives you should be worth 70x33 = $2310. So at the $1800 per kit that I am aiming for it should represent very good value for money.

I have no doubt that this initial prototype will end up costing me far in excess of the cost of adding a megasquirt system, possibly even building a 2180 (I've already spent in excess of $200 on different length vee belts alone ). I won't even bother trying to count up my own time because I know for sure that at my professional charge out rate buying a turn key 2180 would be small change. There's probably 70 hours just in typing posts for this forum - imagine how much time I've wasted actually building this thing Unfortunately that is just the cost of R&D, this stuff takes time and it takes money to get right.

As I always say - "if it was easy, everybody would be doing it".

Mick.

[T-34]

Have you done any more work on the tension setup?

I've ordered a microgroove serpentine kit and am just waiting for that to arrive. I've also secured a stack of different sized pulleys for the charger so should be good to go once I've figured out what belt length I need.

I've been trying to negotiate with the supplier for a bulk purchase on the serpentine kits but they are either very slow at replying or are simply not interested. If I don't hear back, once I've got everything figured out I will draft it up and get some quotes for getting it CNC manufactured locally.

I already sourced a tool for turning the pulley grooves on my lathe as I was originally considering making the pulleys myself (a thread chasing die is perfect for this), unfortunately there is a massive amount of time to manually turn a billet blank into a pulley and I don't think it would be cost effective for me to do it. CNC is definitely the way to go here. Machine time is much less and the finish is much better.

Still waiting for my 24mm chokes to arrive (Damn you Australia Post) hopefully they will be here this morning.

[T-34]

Yay, new chokes just arrived. I'm off to go fit them.

[andy198712]

Good luck!

[T-34]

Good luck!

Cheers

For example...

Let say a turn key 2180cc engine costs $5k - it puts out 150bhp - that's 5000/150 = $33 per bhp
lets say that my kit with megasquirt costs $3k it puts out 70bhp - that's 3000/70 - $43 per bhp

With my kit you get much less bang for your buck and still only have a maximum of 70bhp. Chances are that if you use your 1600 as the core the turn key 2180 won't even cost you $5k. My kit only works financially if the overall cost is more appealing than paying the extra for a full engine build. Interestingly, if we take the $33 per bhp as the baseline value, the 70hp that my kit gives you should be worth 70x33 = $2310. So at the $1800 per kit that I am aiming for it should represent very good value for money.

just had a thought about this and what I wrote is incorrect - the cost is for the ADDITIONAL horses - the engine already has 50bhp!!

so...

Let say a turn key 2180cc engine costs $5k - it puts out 150bhp (an extra 100bhp) - that's 5000/100 = $50 per bhp
lets say that my kit with megasquirt costs $3k it puts out 70bhp (an extra 20bhp) - that's 3000/20 - $150 per bhp

Three times as expensive !!

At the planned $1800 for the kit it costs 1800/20 = $90 per bhp - not quite as good value as building a 2180, but then you don't have the same initial outlay and it can be fitted in a weekend.

[T-34]

Well just fitted the chokes up and instantly I can tell the difference. It's waaaaaaaay too rich but there is no hesitation when opening the throttle fast. Now to get back to dialling the jets in.

[gearheadgreg]

At the planned $1800 for the kit it costs 1800/20 = $90 per bhp - not quite as good value as building a 2180, but then you don't have the same initial outlay and it can be fitted in a weekend.

Thats the thing - your motor is still there and complete, and your additional power can always be removed and installed on another vehicle if the original is sold, as well. You NEVER get the money of a 2180 (or whatever) back out of a vehicle sold.