TPS for Quick Fuel Carburator?

[RockBit]

I have a 482 side oiler with a Quick Fuel HR-780-VS. The engine was built by Brent Lykins and runs very well. Starts easily, lumpy idle, and pulls like a freight train. It is 100% street driven.

Brent installed an MSD Pro Billet distributor (8594). He instructed me to set the all in timing at 34°, which I did. It is all in at about 3000 rpm.

When I bought my MSD box prior to completing the car, Tom Kirkham and Lippy both posted threads about their successful experience with the programmable 6530 unit, so that is what I got. Up until now I have not used the programmable feature of the 6530, but would like to do so.

I hooked up a vacuum gauge and put it in the cockpit so I could see what the manifold vacuum was at various times. The manifold vacuum on my engine is about 6 in Hg at idle. Vacuum goes up to about 18 in Hg at the peak at a little over 2000 rpm (cruise), then starts falling off as I give it more pedal.

This type vacuum curve, as I understand it, does not lend itself well to using a MAP sensor to gauge engine load for the 6530. I decided at that point to look at using a throttle position sensor (TPS) instead, as Tom Kirkham did.

Holley sells a TPS for electric choke carburators, but a call to them revealed it will not fit on my QFT carb. They suggested a universal TPS made by B&M Racing (part number 120002). The instructions with this B&M unit are hideous, and the only review I found was on Summit and rated it as poor.

Innovate makes a TPS for carbs but it will not work with an electric choke. Another one I found was the AccuLink TPS kit, but I'm not sure it can be mounted on my carburator.

Does anyone know of an appropriate TPS? Or is there any other way to get engine load information to the MSD 6530?

Thanks in advance for any help.

[Gaz64]

Here is one option Chris,

FST has beaten me to my idea on my billet base:

https://www.speednik.com/wp-content/...24-960x640.jpg

I like the CB Black Box much better than the 6530.

https://www.youtube.com/watch?v=7qv87mFw6T4

Gary

[RockBit]

Gary:

Thanks for the reply. Your links led me to th following article

https://www.streetmusclemag.com/tech...arburetor-tps/

Which has a better description of the AccuLink kit than their sales literature. I might be able to adapt it to my carb, as it looks pretty flexible.

I know your preference is the CB black box, but I already have the MSD unit. I hope to make it work.

Thanks for the info.

[Gaz64]

Hi Chris,

Here is another option similar to the FST fitment:

https://www.efihardware.com/products...-for-Delco-TPS

Gary

[RockBit]

Thanks Gary. After looking at the options and looking at the linkage on my carb, I ordered the Acculink set up. I believe I can make it fit on my engine.

https://www.hgmelectronics.com/acculink-tps-kit/

Their documentation looks good. I should get it in about 3 days and then can proceed with the install.

I appreciate your help.

[Gaz64]

You're welcome Chris.

I wish you well with your installation.

Gary

[olddog]

FYI -

A mass flow EFI system uses the engine displacement times RPM times a pumping efficiency constant. They put this in the denominator.

They measure the air flow into the engine with the MAF meter. This goes into the numerator.

The engineering units of measurement are corrected such that the units in the numerator and denominator are the same. This gives a very accurate calculation of engine load. This is what the timing is based on in an EFI system.

Before Mass Air they used speed density, which is MAP and TP sensors. Based on MAP, rpm, and TP they estimated what the Mass Air Flow was, and this was used in the numerator.

As you know speed density does a very poor estimate, when the MAP is very low at idle and increases with rpm.

Then there is a strategy called Alpha-N. It simply used the TP sensor and rpm. This is what you will be simulating. It is the least accurate of them all, but it has its better points too. It has way less complicated calculations to do and way less sensors to go bad and lie to it. Inside a MASS Flow EFI is a copy of the Alpha-N. It is used as a sanity check to verify all sensors are reading within tolerances. It is also looked at when rapid throttle position changes happens, as the Alpha-N is quick to calculate without sensors lagging reality.

So the TP you are going to use will work similar to what an Alpha-n EFI strategy would do. It is a ball park system, not a highly accurate system, but compared to a vacuum canister and weights on springs? Likely not too shabby.

[RockBit]

olddog - Thanks for the clear explanation. I am anxious to get my installation finished to see how it changes the performance of my engine.

I received the AccuLink unit and installed it. It fit the QFT carb nicely and was easy to install. I still have several things to do:

- Phase the rotor.
- Lock out the distributor.
- Determine the timing curve I am going to use and upload it to the MSD 6530.

Here is a pic of the TPS as installed.

[RockBit]

I really thought I would be finished with this project and be able to close out this thread, but I have had a couple of setbacks. I will finish it at some point.

First, I decided to relocate my MSD box from being mounted upside down on the bottom of the glove compartment. It was visible below the dash when standing at the rear of the car and had bugged me for a while. After seeing AndrewB's mounting on the end of the glove box, I decided that was a beter solution. Unfortunately after I moved the MSD none of the wires were long enough. I spliced in extensions to all wires, soldering and heat shrinking the joints. I also added an MSD capacitor into the power leads as recommended by PatrickT and others. In the middle of all of this, we took a vacation, so I finished it up when I got home.

I started the car up after rewiring and it ran beautifully, as it always has. Now the MSD box is no longer visible, and is protected from electrical surges by the capacitor.

I then waited until a couple of events went by before proceeding, as I wanted to drive the car to them.

Just as I was ready to finish the project, our house got hit by an EF3 tornado. There was no structural damage to the house, just windows and holes in the roof due to flying debris. Also, the detached garage where I keep my cobra held up except for the glass panels in the garage door.

Below are a couple of pictures I took after the storm. The debris on the driveway is mostly from the house next door to mine that totally collapsed.

Unfortunately, we got a lot of water in the house and had to relocate until the house is restored, which will be about 3-4 months.

Due to the flying glass, my car looks like I drove down a gravel road at 100 mph in reverse. Every panel on the car has chips in the paint. I will be having a full repaint done on it starting next month (insurance is covering it), so I will be without the car for 2-3 months.

I will finish this thread up next spring. On an additional note, there were 9 tornados in Dallas that day, and no one was injured even though many homes and business were completely destroyed. A Home Depot about a mile from my house was totaled as the roof collapsed, but the manager had closed the store and sent everyone home about 30 minutes before the storm.