Throttle position Sensors.

[Rockfrog]

Ok, for the last 13yrs or so I've always been led to believe that only the Renix TPS reads a climbing voltage signal. That HO reads a descending voltage signal. And that we HAD to use the Renix TPS. 

 

Well that's just simply not true. 

 

The 91+ HO TPS reads exactly the same was as the Renix TPS. They changed the way the TCU reads the signal. Also nearly every TPS out there reads nearly identically. There are ones that rotate left, ones that rotate right, but for the most part they all read 0-5V.

Honda, GM, Jeep/Dodge, Ford .... 

 

Here's the rub, they start at different points in that range. HO starts at 0.2V, GM is between 0.5-0.7v blah, blah, blah. They all end at ~4.8v minimum at WOT. 

 

So with that little tidbit, I aim to go on a search, and modify as i go, to find my cheap sensor, and make the bastard adjustable. Not just the usual hog stuff out and modify the sensor type hacks. I want drop in, adjust and go. 

 

On that note, i have been using a GM sensor for some time, about 7yrs or so now. Gm 2.8L applications, TH32 for the renix thottle body, and TH47 for an HO throttle body. They rotate opposite to each of other. The sensors were inexpensive, at least they used to be. Prices are climbing, and the sensors are old tech as it were. Same as the TH258 used 87-90. 

 

So, the GM Vortech TPS is cheap, and so is the dodge/jeep 4.7L sensors. I'm planning to add a 4.7L throttle body at some point as well anyway, so ... 

 

Gonna play with this one a bit, modify the mount and home fab a bracket to mount and allow for adjustment. Two birds one stone. Unfortunately it's going to be a dead end at some point as TPS prices will eventually climb again. They are the dodo these days as new throttle bodies are all fully integrated these days so no replaceable TPS. But I'm gonna run with it for as long as I can. 

 

Should be simple enough, we'll see whatbi end up with for a bracket, but it looks like most TPS's are fairly similar in mounting and actuation. Especially the choices i currently have in hand (91-95, 96-98, 99+ 4.0L, GM 4.3L Vortech i think late 90' to early 2000's S10 but also appears to ve current-ish for LS as well, and finally the not so well loved 4.7L dodge/Jeep used on nearly every V6/V8 since about 97). 

 

This is what I've had for at least 7yrs now, swapped a wire around in the connector, made an adapter with little more than a hacksaw, handfiles and a hand drill. So the new path should be just as simple. 

 

Anyone see any fault to this line of thinking? 

 

Sorry Automatic guys, i have no way around the dual outlet TPS thing, but that won't be an issue for the HO guys. So once again, this is mainly just a Renix problem as usual. But dammit, I'm gonna keep her running till i get burried in her. 😁

[Rockfrog]

so working through this issue, making the adapter for the TPS is fairly straight forward ... simple sliding block arrangement. Since I'm in the Dorms at school (3rd tr Millwright) for the next two weeks, actually making the block will have to wait. I MEAN i would just bang it off but might run into issue with the residency. so i have at least worked out the template for the adapter, yay.

 

so next issue is high volume throttle ... usually makes for a twitchy throttle ... but I've never seen anyone address the issue. the throttle actuation needs to slowed down to compensate. As it so happens the 4.7L throttle body has a partial compensation built in, the throat is reduced and then expanded to increase velocity (thereby reducing pressures, and then increases it as flow drops on the back end) so controls the issue to almost 1/4 throttle where the butterfly unshrouds and the fun begins, this is usually removed as it's looked at as a flow restriction ... well, it is, but for a reason. This part we keep.

The next issue is opening speed ... instead of retaining the same pivot point, designed to move a smaller throttle blade at a specific rate, we need a longer distance between pivot and actuation point. extending the lever. BUT, we have to stay within the range of travel allowed by the throttle cable. So that's the next trip.

If that doesn't get me the results I want, plan B is a Jeep Liberty throttle body ... same mounting pattern and design, but it brings the problem of the two pin IAC (basically a single acting spring return linear actuator instead of the 4 pin double actuated IAC we all know). thankfully the stock 4.0L solve that issue with a removable IAC housing. So plan B includes remote mounting and IAC ... which then opens up an almost unlimited range of throttle bodies available.

 

Hi, my name's Dave, I do dumb $#!& so you don't have to go past the "I wonder if" stage  ...

 

it's OK, I talk to my self alot anyway.

I'll drop some pictures when i get some time.

[Rockfrog]

and in case anyone is wondering what this is all about ... 

 

it's all about a cheaper more accessible TPS option  ... with some farting around in the mix. I know the larger TB has downsides, and I want to explore that, as my current setup lacks throttle response off the line (probably due to the 99+ intake and the HO throttle body size compared to plenum volume argued against using stock 1990 Auto Renix tuning all in an 88 5spd). The throttle body and other crap is simple ramblings, and I do weird stuff ... ADD and curiosity make for some wild trips. 

 

I also plan to play with swapping intakes (back to a log) and possibly adding or reducing plenum volumes to both at some point to see what happens. I have no real desire for HP my aim is pure and simple Torque  ... but i also happen to drive something (yup, Ratmanche is my Daily) that is 34 years old and half the parts attached to it are long out of production, and what is still available is of questionable quality.

 

 

[Ωhm]

34 minutes ago, Rockfrog said:

I have no real desire for HP my aim is pure and simple Torque

Doesn't Torque have a lot to do with gearing? Now if your interested in throwing more fuel at it, check these links out.

 

Renix Wideband O2 Control Using the R.E.M.

 

REM Wideband o2 Sensor Converter

 

[Rockfrog]

torque is a measure of what the engine can do (WORK), gearing makes it easier to apply that work, and then HP is simply how fast that work can be applied (WORK over time). 

 

I have thought about moving to a wideband, but haven't been bothered to yet  ... I still get about 18mpg with my road pig rolling on 35's so not too bad at all, not the 22mpg it used to get as a 2wd though. but I didn't build (still am) to roll down the highway efficiently, it just has to as a daily driver.

[gogmorgo]

13 hours ago, Rockfrog said:

so next issue is high volume throttle ... usually makes for a twitchy throttle ... but I've never seen anyone address the issue. the throttle actuation needs to slowed down to compensate. As it so happens the 4.7L throttle body has a partial compensation built in, the throat is reduced and then expanded to increase velocity (thereby reducing pressures, and then increases it as flow drops on the back end) so controls the issue to almost 1/4 throttle where the butterfly unshrouds and the fun begins, this is usually removed as it's looked at as a flow restriction ... well, it is, but for a reason. This part we keep.

The next issue is opening speed ... instead of retaining the same pivot point, designed to move a smaller throttle blade at a specific rate, we need a longer distance between pivot and actuation point. extending the lever. BUT, we have to stay within the range of travel allowed by the throttle cable. So that's the next trip.

If that doesn't get me the results I want, plan B is a Jeep Liberty throttle body ... same mounting pattern and design, but it brings the problem of the two pin IAC (basically a single acting spring return linear actuator instead of the 4 pin double actuated IAC we all know). thankfully the stock 4.0L solve that issue with a removable IAC housing. So plan B includes remote mounting and IAC ... which then opens up an almost unlimited range of throttle bodies available.

 

Hi, my name's Dave, I do dumb $#!& so you don't have to go past the "I wonder if" stage  ...

 

it's OK, I talk to my self alot anyway.

I'll drop some pictures when i get some time.

Not really sure if it helps any, but IIRC at least one of my Ladas wrap the throttle cable around a little cam with a groove instead of the cable hooked to a fixed pivot point. I’m a long way from the thing to take a picture but here’s a bit of a scribble. 

because the length of the pivot arm changes as the throttle moves through its sweep, it would change the sensitivity of throttle response depending on where you are in the sweep. In the one I drew the longer lever arm at the start of travel would slow down changes in butterfly position at closed throttle relative to speed at open throttle.

I couldn’t tell you what issue the Soviet engineers were trying to address with the lever arm (or even if it was deliberate), it’s also possible they were trying to adjust input force compared to return spring strength for more consistent feel or something. Also my drawing is exaggerated compared to the real deal… but it’s a thing that does a thing tangentially related to what you’re talking about. 

[cruiser54]

My Alfas have that also.

[Rockfrog]

yep, and a lot of more modern TB's do also. technically the retainer used on the 4.0L's is considered more of a carb connector type

 

I'm gonna fart around with this one for a bit, I've also toyed with the idea making my own intake but that's a crap tonne of math. Thinking along the lines of the Ford 4.9L intake. but then that would require a smaller throttle body. at the same time I'm also reworking my cold air intake (yes, it's an actual true cold air intake)

to allow some amount of warm air in for winter warm ups, and reworking my hood for a more aesthetic appearance (so new scoop design, and that requires a new layout for the intake filter housing).

 

Another project that eats my time is a temperature controlled PWM fan control. one that's actually programmable and not just the generic X fan comes on now and Y fan comes on 10 degrees later. I want something that will receive temperature data, and output that to a readily available OEM fan control module (which require a PWM input), and have the ability to run each fan at a completely differing set of variables. And not spend $300+ for a simple parallel control that cost about $10 to produce.