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3rd gear flat spot
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bluedot
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PostPosted: Sun May 22, 2016 11:01 am    Post subject: 3rd gear flat spot Reply with quote

I just put a set of dual Kadrons from Kaddieshack on my 1600dp (stock internals I think?). They tweaked them, and the jets seem good. Clean plugs, clean exhaust. It uses a pertronix SVDA "flame thrower", and thru the course of cleaning up the motor we've adjusted the valves a couple times - replaced the cap, rotor and wires - tuned and tweaked the carbs with more accelerator pump.

Idles perfect. Keeps its idle. No pops, no backfires. Quiet and cool.

1st gear perfect to 5k
Shift to second, no flat spot
Shift to third and it drops for a moment and then kicks in **the problem**
4th gear, no bog at all.

My timing is at 30BTDC, my advance takes it to 40 when the vacuum is connected. It idles at about 10deg. One carb connection (drilled by Kaddieshack) to the distributor.

I have read that an SVDA works best with it's old single carb that had tons of vacuum. (34pict)

It's using a header type exhaust on it.

I feel like I got it 99%, but this third gear bog is baffling. Could it be a vacuum issue? Could 2deg of timing make a difference in only third gear? Can I even expect to get this 100% with my SVDA, or should I be using a dizzy with a tweakable curve?

Thanks for any and all input.

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clonebug
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PostPosted: Sun May 22, 2016 1:02 pm    Post subject: Re: 3rd gear flat spot Reply with quote

What size are your mains???

A decent AFR gauge is around $200.00. If you had one installed it would instantly tell you what is going on.
If you are running 130 mains , my guess is it is going a little lean at the high load area when hitting third gear.
First and second gear won't put enough load on it to feel the leanness.

On my 1600 DP i had to go to a 140 main to get it to run good.

I almost burned the engine up running too lean at high speed cruise at 65 mph with the 130's.
After the 140 mains I never had a problem again.

That was a long time ago though.

I had the KS throttle bodies redone and one drilled for the vacuum port for the distributor.
They have been on the shelf for 5 years now.
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bluedot
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PostPosted: Sun May 22, 2016 1:11 pm    Post subject: Re: 3rd gear flat spot Reply with quote

I would LOVE the idea of diagnosing things with something like this.

I have no idea the jets currently, they were sized by KS for my elevation and engine size. I didn't realize it could be a jetting thing since it ran good in the other gears.

I had an 87 westy we put a Tiico in, and it had an OBDII connection to my laptop, and I was able to tune it super tight. This all mechanical thing is pretty voodoo to me.

Can one just weld a bung into the muffler for one of these, or does it require exact placement, ie the Vintage Speed $$$ exhausts?

Seems like a digital distributor and an AFR would make it tuneable like a modern car?
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clonebug
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PostPosted: Sun May 22, 2016 2:18 pm    Post subject: Re: 3rd gear flat spot Reply with quote

I use the PLX O2 sensor.

Here is the Gen 4 model.

Install a bug right in the merge of the header or right after it at the 10:00 or 2:00 o-clock position

http://www.plxdevices.com/Wideband-O2-Touch-Screen-Multi-Guage-p/897346002719.htm

I have the Gen 3 version.
It really is a nice system and the digital gauge allows you to add other sensors and display them also if you ever want to add on.

It will tell you exactly what is going on with fuel.

I doubt your issue is ignition if you have a half decent distributor in there.

It is more likely a fuel issue where it is going lean at the full load area for a short time.

A longer accel shot might help or a slightly bigger main.

If I were you I would get a cheap set of jet drills so you can measure the exact size of the jets. I have had new ones mark as one size and they end up being a LOT bigger.
The only way to know is to measure them.

Here is a set of drills that are very reasonably priced and you can use them to check you jet sizes or drill them to the size you want.
They go in 0.05 increments.

https://www.widgetsupply.com/product/BBL50.html

For the price you can't go wrong.

I used them during my blow through carb experience.
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



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bluedot
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PostPosted: Mon May 23, 2016 9:53 am    Post subject: Re: 3rd gear flat spot Reply with quote

Thanks clonebug! You've opened up a new world to tuning my ghia.

I may go with more of a temporary type gauge system as I don't want to add any more gauges or wires into my ghia - maybe the type that Aircooled.net sells? (I'm into the vintage look on my dash)
Image may have been reduced in size. Click image to view fullscreen.

http://vwparts.aircooled.net/Innovate-LM-2-Wideband-Oxygen-Sensor-Kit-Basic-p/innovate-3837.htm

As I started looking into this electronic sensor systems, I see that CB Performance is doing a "Black Box" and a digital distributor that allows tweaking of advance curves.
https://www.cbperformance.com/Articles.asp?ID=320

With the promise of a better running engine, more HP and better mileage - I'm tempted to whip out my credit card. I will admit though, the simplicity of my beloved aircooled would be frankensteined into contemporary tech. Would I regret not learning how to do it well "Old Skool"?

Here's a post I found about tweaking the wideband results after installation of the sensor system.Yes - that's 71 pages of posts on this tuning. Is it a rabbit hole worth diving into?
http://www.thesamba.com/vw/forum/viewtopic.php?t=2...d9547418dc
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bluedot
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PostPosted: Mon May 23, 2016 9:54 am    Post subject: Re: 3rd gear flat spot Reply with quote

clonebug wrote:
I used them during my blow through carb experience.


This is a telling quote of what your final solution was. Smile
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mikedjames
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PostPosted: Mon May 23, 2016 12:04 pm    Post subject: Re: 3rd gear flat spot Reply with quote

The whole point of fitting the AFR gauge to the dash is that it shows weird transient effects in real time - like the PLX devices gauge I fitted will also graph the normal-lean-rich-normal spikes you get when you floor a progressive - it samples 10x per second , will even show a flicker if a cylinder is misfiring at idle.
The PLX display is so thin, I have mine pushed into a piece of 3/8 plywood fitted on top of the surface of the dash as an enlarged radio surround so there is no big cut out hole, and I use a gap in the hacked up metal around a PO's messy fitting of a DIN mount radio in the centre of the dash to slot the wires through.
Having a unit you have to plug in means it will not be there when the critical combination of vacuum, throttle, mixture , RPM and engine loading cause a problem.
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PostPosted: Mon May 23, 2016 12:13 pm    Post subject: Re: 3rd gear flat spot Reply with quote

bluedot wrote:
Thanks clonebug! You've opened up a new world to tuning my ghia.

I may go with more of a temporary type gauge system as I don't want to add any more gauges or wires into my ghia - maybe the type that Aircooled.net sells? (I'm into the vintage look on my dash)
Image may have been reduced in size. Click image to view fullscreen.

http://vwparts.aircooled.net/Innovate-LM-2-Wideband-Oxygen-Sensor-Kit-Basic-p/innovate-3837.htm

As I started looking into this electronic sensor systems, I see that CB Performance is doing a "Black Box" and a digital distributor that allows tweaking of advance curves.
https://www.cbperformance.com/Articles.asp?ID=320

With the promise of a better running engine, more HP and better mileage - I'm tempted to whip out my credit card. I will admit though, the simplicity of my beloved aircooled would be frankensteined into contemporary tech. Would I regret not learning how to do it well "Old Skool"?

Here's a post I found about tweaking the wideband results after installation of the sensor system.Yes - that's 71 pages of posts on this tuning. Is it a rabbit hole worth diving into?
http://www.thesamba.com/vw/forum/viewtopic.php?t=2...d9547418dc


I am using this kit on my FI Type 3 to tune the FI for the added displacement and compression (1776 now). Once I am convinced I have the settings dialed in, I'll replace it with the plug for the bung. I can always bring it back out if I feel any drivability issues in the future.

A buddy kids me, as this thing looks like a Breathalyzer suction cupped to my dash. Another reason not to leave it attached!
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clonebug
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PostPosted: Mon May 23, 2016 8:43 pm    Post subject: Re: 3rd gear flat spot Reply with quote

KTPhil wrote:
bluedot wrote:
Thanks clonebug! You've opened up a new world to tuning my ghia.

I may go with more of a temporary type gauge system as I don't want to add any more gauges or wires into my ghia - maybe the type that Aircooled.net sells? (I'm into the vintage look on my dash)
Image may have been reduced in size. Click image to view fullscreen.

http://vwparts.aircooled.net/Innovate-LM-2-Wideband-Oxygen-Sensor-Kit-Basic-p/innovate-3837.htm

As I started looking into this electronic sensor systems, I see that CB Performance is doing a "Black Box" and a digital distributor that allows tweaking of advance curves.
https://www.cbperformance.com/Articles.asp?ID=320

With the promise of a better running engine, more HP and better mileage - I'm tempted to whip out my credit card. I will admit though, the simplicity of my beloved aircooled would be frankensteined into contemporary tech. Would I regret not learning how to do it well "Old Skool"?

Here's a post I found about tweaking the wideband results after installation of the sensor system.Yes - that's 71 pages of posts on this tuning. Is it a rabbit hole worth diving into?
http://www.thesamba.com/vw/forum/viewtopic.php?t=2...d9547418dc


I am using this kit on my FI Type 3 to tune the FI for the added displacement and compression (1776 now). Once I am convinced I have the settings dialed in, I'll replace it with the plug for the bung. I can always bring it back out if I feel any drivability issues in the future.

A buddy kids me, as this thing looks like a Breathalyzer suction cupped to my dash. Another reason not to leave it attached!


I had a LM-1 for a couple years until it puked. It was bulky and took up a bunch of room in the buggy.

Image may have been reduced in size. Click image to view fullscreen.


I like the PLX much better since it is so easy to hide it.
The gauge also read the Voltage so I pulled my volt gauge out and installed it there. Now it does AFR and Voltage with just a press of a button on the face of the gauge.

This is all I see with the PLX.

Image may have been reduced in size. Click image to view fullscreen.


The controller is hidden under the dash.

Image may have been reduced in size. Click image to view fullscreen.


One nice thing about the PLX is if you need to make the wiring from the O2 sensor to the controller longer it is just a standard "Mini Molex" connector which is available online and you just make a harness extension any length you want with some 18 ga. wire. You can then put the controller wherever you want. I needed about 2 extra ft to put it under my dash.
I have my FI ECU correcting AFR with EGO so it reads my AFR map and adjusts accordingly.
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash


http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936
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clonebug
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PostPosted: Mon May 23, 2016 8:50 pm    Post subject: Re: 3rd gear flat spot Reply with quote

bluedot wrote:
clonebug wrote:
I used them during my blow through carb experience.


This is a telling quote of what your final solution was. Smile


I did put 7000 plus miles on that blow through carb setup......while it was completely driveable and fun it never ran as good as I wanted it to.

FI was the way to go for me..........3 yrs. and over 10,000 miles since I have smelled gas on my hands....... Rolling Eyes Laughing (Summer daily driver buggy)

It has allowed me to go from 11-13 lbs boost to the 22 lbs. I am running now.
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash


http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936
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MURZI
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PostPosted: Mon May 23, 2016 9:06 pm    Post subject: Re: 3rd gear flat spot Reply with quote

Before you blow money tuning Kadrons buy some idfs or hpmxs. Much better running carbs. Easy to tune too.
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PostPosted: Mon May 23, 2016 9:24 pm    Post subject: Re: 3rd gear flat spot Reply with quote

MURZI wrote:
Before you blow money tuning Kadrons buy an EFI setup. Much better than running carbs. Easy to tune too.


Fixed it for ya Murzi!!!! Laughing Laughing Cool
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash


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PostPosted: Tue May 24, 2016 5:02 am    Post subject: Re: 3rd gear flat spot Reply with quote

Do the pump jets squirt right away with no interruption in flow?

Is your fuel pressure too low?
Possibly the float bowl is running low by the time you hit 3rd so the squirt is off or intermittent. 4th works because the fuel level has had time to catch up...
I love most Kadrons however over the past 5 years I have sent several of the new sets back.
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bluedot
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PostPosted: Thu May 26, 2016 10:51 am    Post subject: Re: 3rd gear flat spot Reply with quote

Swap em for IDF's huh?

Since my post - things have gone downhill. A fuel leak inside one of the carbs filled my oil with gas. (Again) I then reset the regulator to 1.5 - removed the intakes and redid the gaskets thinking I may have had vacuum leaks. (Those empi intakes don't fit the OG tin very well. I modified them on a belt sander to get them to fit flat on the heads better). Vacuum leaks gone. (I thought I had it!)

She idled beautifully, but popped and snapped with throttle. Fouled the plugs, again. Then the next day - her idle was all over the place! Sometimes rev up, sometimes die. Sometimes a big black puff and a backfire. No consistency AT ALL. I turn mixture screws and nothing happens unless they are all the way in and seated, and there I can tell she's lean cuz of her pops and backfires happen at idle.

I think there's something wrong with the carbs that's haunted me since I installed them. Or maybe I am just daft. It's a possibility, eh?


Last edited by bluedot on Fri May 27, 2016 11:38 am; edited 1 time in total
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PostPosted: Thu May 26, 2016 1:10 pm    Post subject: Re: 3rd gear flat spot Reply with quote

You should go to the "dark" side.
You will never look back.....In fact after EFI a turbo is the next logical step.....😆😆😎
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash


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PostPosted: Fri May 27, 2016 8:27 am    Post subject: Re: 3rd gear flat spot Reply with quote

I milled flat spots on a old 3rd gear to hold the pinion, works great.those fine teeth gear's are hard.
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PostPosted: Fri May 27, 2016 8:53 am    Post subject: Re: 3rd gear flat spot Reply with quote

mark tucker wrote:
I milled flat spots on a old 3rd gear to hold the pinion, works great.those fine teeth gear's are hard.


Put the pipe down Tucker!!!! Laughing Laughing
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vwracerdave wrote:

Take a good long look in the mirror and report back on what you see.


Paul.H wrote:
That one line on that chart is probably better info than you can get from this place in a month



My Megasquirt Fuel Injection Turbo Buggy Build
Water/Alcohol Injection
Audi TT intercooler
Upgraded to MS3Pro-Evo
EcuMaster PMU16
ECUMaster ADU5 Digital Dash


http://www.shoptalkforums.com/viewtopic.php?f=3&t=127936
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bluedot
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PostPosted: Sun May 29, 2016 10:40 pm    Post subject: Re: 3rd gear flat spot Reply with quote

An update. After she wouldn't even run - I took off the top and found a bunch of stuff in the float bowl - like casting slag or sand. Big particles. I think something gave way from a passage after manufacture!

Lady luck had forgotten my name!

Sent them out for a cleanse and checkup. There is hope.
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PostPosted: Mon May 30, 2016 2:00 pm    Post subject: Re: 3rd gear flat spot Reply with quote

clonebug wrote:
mark tucker wrote:
I milled flat spots on a old 3rd gear to hold the pinion, works great.those fine teeth gear's are hard.


Put the pipe down Tucker!!!! Laughing Laughing
but how else an I to torque that darn thing without that 2 foot long pipe? Shocked and how did you know I was holding it?. yes for some reason carbs tend to be full of shit,I gess they just dont bother to clean them very good. thus.....always take them appart and rebuild them befor usage.........just like everything else we get. Wink
lady luck didnt forget your name, she just didnt like that blue dot on your 4head. Rolling Eyes
and remember to put new fuel filters befor each carb...and use good fuel line too....I also have a filter before the fuel pumpunhousen so nutten gets in there. my 44hpmx's have had 2 or 3 idle jet clogs in about 13 years and no other issues....well i did have the top screws loose one tyme Embarassed
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bluedot
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PostPosted: Wed Jun 15, 2016 11:58 am    Post subject: Re: 3rd gear flat spot Reply with quote

Updates!

1 carb had a defective needle and seat, and was causing me troubles - so Kaddieshack did another go around with them, and BAM! They're running so beautifully now.

I added the velocity stacks as part of this new work. A Vintage Speed muffler shows up today with a sensor port so I can go to the next step.

Thanks for all your feedback!


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