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Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

Knowing that this needed to be done at some point soon, I banged this out.

However, it left me with a question. Doesn't the DITC need the throttle 'switch'? Plus with FrankenCIS-E, i don't think I need the TPS right away or at all since its gets the air plate position. Which I knew already but always seem to forget. BTW this is the TPS recommended by Vaughn a while ago or at least that's how I remember.

Quick and dirty scan (Screen shot like my Dad would do it

)

Test Print

Latest version to be printed with ASA

_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

924RACR · Posted: Thu Aug 17, 2023 1:17 am Post subject:

Does that clear the intake? I recall clearance was poor on the bottom of the throttle body... I cut my throttle shaft down to help (also didn't need it as long on the TPS vs. the original switches). Pretty sure the adapter plate I made was thinner than your mount.

Though for sure if you didn't have to cut down the shaft, that's an easier install.

Dunno about DITC needing the throttle switch, but I think not? Have to check wiring diagrams...

OK, per the manual ('81 service update), if the throttle switch is disconnected or fails, there will be no ignition retard during starting or coasting, and the idle speed will be too high. Pretty sure based on that statement that it's only using the circuit that indicates when the throttle is closed (0%). Could be simulated... or you could just bin all that, go full modern system, and never look back...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

Need to adjust tolerances slightly. This is because I tightened up some of them and it resulted in a slight piloting (centering) issue for the TPS at the shaft. Could also be because of the material change or combo. That's why TPS looks like its floating on the adapter. So far so good really. Plenty of space to Intake. Will need to check original TPS output exactly and go from there. Once FrankenCIS is in play the full TPS just gives me tuning options. I also like the fail safe feature if losing Microsquirt. It still functions as CIS

The pipe rests on it so might have to tweak things there

_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

924RACR · Posted: Thu Aug 17, 2023 8:41 pm Post subject:

Losing Microsquirt? I have to say, I've been running mine for a few years now, and it's been stunningly reliable. I'm having so much fun with my car now, compared to before, I can just enjoy it and focus on cleaning it up instead of constantly fighting to make it run.

Biggest obstacle now is just getting the AC cleaned out and running again; waiting on my AC guy plus my own spare time to rock through that. It gets a bit tiring to drive in the heat and construction without - at which point I take my minivan. That or I need to haul racecar parts around.

_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

I'm working on a similar small project at the moment...but for the NA throttle.
I'm trying to find a simple and cost effective way to install a TPS for my EFI kit.

Wasn't there a spring where the adapter is now?
I'm having an issue about that...as i think i'll need a custom made smaller spring that will allow me to use part of the shaft for the TPS.
My rule is no welding to extend the shaft...as this should be doable in the average home garage.

924RACR · Posted: Thu Aug 17, 2023 9:35 pm Post subject:

I have the same issue on my horizon, as I would like to work up the needed bits to Microsquirt the NA racecar, and yeah, the NA TB is a lot harder to set up as such.

I have heard noises that there might be a similar VW throttle body with a TPS or TPS-compatible setup... just haven't made time to dig that out...

Edit: Nope - the MK2 Golf TB is the same as ours, pretty much. Maybe I'll tear apart one of my spares and see if there's a way...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

I'm using the Golf/Rabbit MK2 GTI TB, its a 30% larger flow area TB and has a longer shaft with two springs on it, i think i can get away by only using one spring and mounting the TPS in place of the second spring.
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Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

Sounds like the S2 TB is much easier. No spring etc. Springs are on the opposite side by cable. One is inline and the other at the end of an arm

I will look at the NA since you made me curious and the MK2 TB as well. Jacob has the MK2 TB and we were just talking about the TPS situation when showing him my progress the other day. If we have any weird ideas I'll gladly share

I also need a TPS for the '80 NA which was going to be megasquirted originally. If I would ever get to the last 5-10% of this NA project

Had this on my phone showing the S2 springs

_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

924RACR · Posted: Fri Aug 18, 2023 3:33 am Post subject:

Yeah, the S2 931 was cake by comparison, practically a bolt-on conversion.

Definitely looking forward to any suggestions on how to manage the early TB. As I'm looking at my spare, I'm wondering why it even has the second spring on the shaft, looks completely redundant...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

924RACR · Posted: Fri Aug 18, 2023 5:37 am Post subject:

Ugh. Tore down the spare TB. Annoying design, and of course just as it looks, indeed the plate on the butt end of the shaft - same end we'd like to put the sensor on - has the cam for the spring welded on.

So not real helpful there, no sign of any easy answers. Maybe after cutting that off and ditching one of the springs, as you'd have plenty of shaft length to work with at that point. Mounting would be slightly annoying, would need a fairly non-trivial bracket to bolt to the TB, with some holes probably drilled and tapped into the casting itself ultimately, to give a good base to put a sensor on.

Looking forward to hearing what you guys come up with... might be appropriate to start a separate thread on that...
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

Kind of hijacking but here is my approach for the TPS.
This is a solution for the larger VW/Audi TB that i’m using and i recommend for the guys running the SC kit.
Its just a bracket, 5 min angle grinder job on the shaft and rearanging the spring.

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Supercharger and EFI kits
https://www.the924.com

924RACR · Posted: Mon Aug 21, 2023 2:00 am Post subject:

Oh, yeah, I could see that working, cool, thanks for sharing!
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Mike9311 · Joined: 14 Dec 2004 Posts: 1798 Location: Chicago-ish

No problem Morghen!

Exactly the kind of thread direction I like

So I thought of something too over the weekend for the stock NA and if it works the concept might be usable with others.
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

Curious what you come up for the NA TB.
_________________
Supercharger and EFI kits
https://www.the924.com