JS Safeguard- Knock retard system

This is the place to discuss, or get help with any of your Type 4 questions.

Moderator: Type 4 Unleashed

51MAN
Posts: 645
Joined: Thu Nov 22, 2001 3:01 am

JS Safeguard- Knock retard system

Post by 51MAN » Thu May 16, 2002 3:22 pm

Dont know if LPG has the same "noise" but by advancing the ignition timing you generally get back the little bit of power lost, its a fine line of what is too far, so a gizmo like this could do it.
Most modern cars have anti knock and some advance until knock occurs (maybe they just retard like this one in reality!!) so take full advantage of LPG.

What I might do is build up the "spares" engine on the cheap with high comprssion and see what happens, LPG loves compression!!!
I think LPG has potential as a performance fuel, just noone has done anything with it.
There is the possability to inject LPG in its liquid state, into the inlet track, this would cool the incoming charge and head!!

Mmm, I can feel a project comming on... just got to find some cash for it!!!

Si
1.9 wbx Caravelle of LPG + soon to be 1.7 TIV "Vanagon" also to be on LPG!!!!

JohnConnolly
Posts: 3336
Joined: Thu Apr 13, 2000 2:01 am

JS Safeguard- Knock retard system

Post by JohnConnolly » Fri May 17, 2002 1:23 am

51: I hadn't considered this application, and it's a GREAT idea for dual fuel vehicles! Good thinking

John
Aircooled.Net Inc.


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by 51MAN:
<B>OK, this looks pretty good.
It is just what us people that run on LPG (100 Ron +, 110 Ron typical) are looking for, we can max out the advance and allow the "gizmo" to retard to a "safe" level. of course when we (occaisionaly) run on petrol it will save out engines from the lower octane unleaded (95 Ron).
So how much is it then?? what about a bulk order discount?? and export?? Feel free to mail me...
Cheers
Si</B><HR></BLOCKQUOTE>

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Fri May 17, 2002 1:35 am

Hello-

I would also buy one of these BUT will it fit on a porsche cooled T4 in a T1 ??

If not, it doesn't matter. It should take 5-10 minutes tops to fab up a bracket like this. Just pick a spot that it fits.

Heck, even with a disc grinder, some scrap metal, and a portable drill you can make one up in no time flat. You can even skip the threading step by drilling a 13/32" hole and using a 3/8"x16 nut to hold the sensor on.

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Fri May 17, 2002 1:37 am

Hello-

<B>question is......how easy is it to get to the top right bolt on the bellhousing ? From what I've been reading - that's the most difficult part of the install.
The rest of the install would involve wiring inside the car.</B>

I *think* you're describing the 10mm bolt that holds the starter on, right? I was trying to describe the 8mm bolts that button up the top of the two case halves...

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Fri May 17, 2002 1:41 am

Hello-


51: I hadn't considered this application, and it's a GREAT idea for dual fuel vehicles! Good thinking

That is a bitchin' idea!

I have a (perhaps stupid) question: will the unit work with a different fuel? Do detonation waves caused by LPG look the same as gasoline?

Of course, even if not, you could set the distributor to give the correct advance for LPG and switch on the Safeguard only when you are putting gasoline in the car. Still pretty cool :-)

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Fri May 17, 2002 1:52 am

Hello-

Re: gaps and voltage drops... not all gaps are created equally.

Gases at a certain state have a property to them. I forget what the heck it's called, but its units are volts per unit length. Basically, to figure out the voltage drop across a gap, take this coefficient and multiply it by the gap length to get the voltage drop. Maybe the resident EE around here remembers what the proper name is :-).

Atmospheric air is around 30,000 V/cm. So, a 0.5mm-1mm gap takes about 1,500-3,000 V to jump across. This is *roughly* equivalent to the voltage drop from the rotor to the cap.

The coefficient for highly compressed air with gasoline mixed in is MUCH higher. How much larger? I dunno exactly. Figure that a stock 1600 with a relatively low compression and decent mixture takes over 20,000V. Turbos, high compression, and rich mixtures will all make this number MUCH higher.

1500-3000V compared to 20000V+... that's why the drop in the rotor/cap is insignificant compared to the spark plug.

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

john@stafford.net
Posts: 783
Joined: Wed Mar 13, 2002 3:01 am

JS Safeguard- Knock retard system

Post by john@stafford.net » Sat May 18, 2002 9:00 am

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Shad Laws:
<B>Hello-

Re: gaps and voltage drops... not all gaps are created equally.

Gases at a certain state have a property to them. [...]

</B><HR></BLOCKQUOTE>

Isn't that principle what VW had in mind with their onboard diagnostic panel for ACVWs? If I got it right, they claimed that they could read cylinder compression via spark plug resistance. Not that I believe it was accurate...

User avatar
danielzink
Posts: 608
Joined: Thu Apr 27, 2000 2:01 am
Location: Lansing, MI
Contact:

JS Safeguard- Knock retard system

Post by danielzink » Tue May 28, 2002 10:26 pm

After emailing with John @ a/c.net a few times tonight, I think I may order the "deluxe" unit with the MAP sensor on it.
to quote John:

"it can be setup to operate like a vacuum advance without having the proper
port OR adequate manifold vacuum. It's also useful as a boost retard or just
a MAP retard on highly tuned engines."

So - I'm running CB's FI which uses a vacuum line from each throttle body to a tee - to the fuel pressure regulator - to advance fuel pressure.

If I run from the tee to the MAP sensor on the J&S box - I can get advance on the distributor relative to MAP (sorta "vacuum advance")- plus knock sensing ability.

Sounds like the best of every world to me... am I missing anything ?


Dan


------------------
my65notch@aol.com

http://users.aol.com/my65notch/index.htm

BergRace
Posts: 606
Joined: Wed Oct 04, 2000 2:01 am

JS Safeguard- Knock retard system

Post by BergRace » Wed May 29, 2002 6:22 am

In this thread it has been claimed that the JS unit gives you "Optimal timing", is this true?
It gives you absolute maximum advanced timing before detonation occures, is this the OPTIMAL timing? Just a question, since I know of situations/aplications where this would not be true.

------------------


P.J.Berg.

MASSIVE TYPE IV
Posts: 20132
Joined: Fri Jul 07, 2000 2:01 am

JS Safeguard- Knock retard system

Post by MASSIVE TYPE IV » Wed May 29, 2002 8:18 am

in almost every case I have seen, more timing makes more power, until it causes detonation. It may not be the best for fuel economy, but right now the blu car only sees the strip as I'm trying to rack miles up on the cIS injected Bus animal...

------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

User avatar
Dave_Darling
Posts: 2534
Joined: Thu Apr 27, 2000 2:01 am

JS Safeguard- Knock retard system

Post by Dave_Darling » Wed May 29, 2002 11:33 am

It wasn't an aircooled motor, much less a VW motor, but Grassroots Motorsports did a bunch of dyno testing last year or thereabouts on an old MG or Triumph. They found that, at least on that old "tractor motor", they got the most power by retarding the timing from the knock point by a few degrees.

So it can indeed happen in real life. Not sure if it can happen to a Type IV, though. Can we assume that Jake has looked at the timing vs. power characteristics on a whole bunch of motors? If so, that's a whole bunch of evidence that Type IVs like more advance.

--DD

------------------
1974 VW-Porsche 914 2.0 (Type IV powered!)

Pelican Parts' 914 Tech Geek http://www.pelicanparts.com

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Wed May 29, 2002 11:47 am

Hello-

Well, here's the little bits I found:

With the Safeguard attached to my engine, I jumped on the laptop and set my timing way too advanced. I jumped out on a flat, empty rural road and went cruising at a constant speed. Charles sat in the passenger's seat with the laptop and I sat in the driver's seat. By keeping the load and rpm on the already warmed-up engine constant at a ~70mph cruise, we were groovy. Since the Autronic computer controls timing by a table, it's easy to change timing while you are driving. We backed off the timing until the Safeguard needed to retard it zero degrees to be perfect. We took note of injector duty (i.e. fuel economy!) and CHT. Then, we backed off the timing 2-4 degrees and checked again. The injector duty didn't change much at all, but the CHT did go DOWN a little bit. Then, we backed off the timing a bit more. Injector duty began to creep up and CHT began to climb very slowly, too.

End result: for the best compromise of gas mileage and CHT, the best timing is roughly 2-4 degrees below the detonation level. Cool, eh?

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

Shad Laws
Posts: 1605
Joined: Fri Aug 24, 2001 2:01 am

JS Safeguard- Knock retard system

Post by Shad Laws » Wed May 29, 2002 11:49 am

Hello-

So - I'm running CB's FI which uses a vacuum line from each throttle body to a tee - to the fuel pressure regulator - to advance fuel pressure.

Stupid question: the lines from throttle bodies... are they MAP lines or ported vacuum lines? If MAP, you are groovy. If ported vacuum, the Safeguard *may* mess with the signal the wrong way.

Take care,

------------------
Shad Laws
LN Engineering
http://www.lnengineering.com

Steve Arndt
Posts: 7185
Joined: Sat Mar 10, 2001 3:01 am
Location: Go Boise State, ID
Contact:

JS Safeguard- Knock retard system

Post by Steve Arndt » Wed May 29, 2002 12:08 pm

They are manifold vacuum. I have a pair of the TBs and here is a pic: http://jubjub.mine.nu/Cb_tb/tb_cb_side-fuelrail.jpg
He is referencing the port between the two throats.
Steve


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Shad Laws:
<B>Hello-

So - I'm running CB's FI which uses a vacuum line from each throttle body to a tee - to the fuel pressure regulator - to advance fuel pressure.</B>

Stupid question: the lines from throttle bodies... are they MAP lines or ported vacuum lines? If MAP, you are groovy. If ported vacuum, the Safeguard *may* mess with the signal the wrong way.

Take care,

<HR></BLOCKQUOTE>

MASSIVE TYPE IV
Posts: 20132
Joined: Fri Jul 07, 2000 2:01 am

JS Safeguard- Knock retard system

Post by MASSIVE TYPE IV » Wed May 29, 2002 12:20 pm

FYI Dyno have a tendency to set timing a few degrees advanced, and the carbs a tad rich compared to what the car actually wants. All testing is done @WOT so it changes things quite a bit in the car...A dyno is a GREAT tool, but it takes more than just the dyno to perfect it in alot of cases. I normally back timing down a couple of degrees and drop one jet size from what the dyno sets me up with..

------------------
Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

Post Reply