Go Back   Third Generation F-Body Message Boards > Tech Boards > Power Adder
Sign in using an external account
Register Forgot Password?

Power Adder Getting a Supercharger or Turbocharger? Thinking about using Nitrous? All forced induction and N2O topics discussed here.

Welcome to ThirdGen.org!
Welcome to ThirdGen.org.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!


Reply
 
Thread Tools Search this Thread
Old 10-29-2002, 04:40 PM   #1
Senior Member
 
Join Date: Apr 2000
Location: Stillwater, OK
Posts: 1,154
Car: 1991 Formula
Engine: 355 DFI Superram w/ R-Trim
Transmission: Probuilt 700r4

Classifieds Rating: (0)
Send a message via AIM to JMatlock88 Send a message via Yahoo to JMatlock88
How would you make a homemade TPS Sensing Switch for 4.0 Volts or Higher at W.O.T?

I debated posting this in the electronics board. I figure it will get adequate attention here as well. I want to make a TPS Sensing Switch for 4.0 Volts or Higher at wide open throttle (by tapping into the middle TPS wire). I want it to be basicly identical to the Nitrous Express $122 switch box. Can anybody think up a wiring diagrm for this logic circut? It needs to complete a circut if it senses a >=4V on the input. It also cannot interrupt the TPS signal to the computer. Any ideas? I like doing things myself like most of you probably do.. Thanks!

edit: The purpose of this type of logic switch is to eliminate an external indication that nitrous is being used. Both for aesthetic purposes or for a hidden nitrous setup if that is what you desire.

If somebody comes up with a working circut, I will make sure it is posted here. Thanks! -Jerod

Last edited by JMatlock88; 10-29-2002 at 04:42 PM.
JMatlock88 is offline vBGarage Page   Reply With Quote
Old 10-29-2002, 07:38 PM   #2
Senior Member
 
Join Date: Jun 2000
Location: the garage
Posts: 1,609
Car: 84 SVO
Engine: Volvo headed 2.3T
Transmission: WCT5
Axle/Gears: 8.8" 3.73

Classifieds Rating: (0)
Send a message via ICQ to SATURN5
Take an opamp and set it up as a comparator. using a variable resistor for feedback you can vari what voltage will trip the output, to trigger a transistor, or small relay. Sorry I don't have a schematic, but it shouldn't take to much to find one. cheers, Bob

Edit:

The Operational Amplifier ( Op Amp ) can be used in many different ways. The Op-amp has two inputs an inverting input ( - ) and a non-inverting input ( + ) and one output. A signal applied to the inverting input will have its polarity reversed on the output. A signal applied to the non-inverting input will retain its polarity on the output. The gain or amplification of the signal is determined by a feedback resistor that feeds some of the output signal back to the inverting input. The smaller the resistor, the lower the gain. Some typical op-amp pin outs are shown below. The most common are the 741 and 1458 dual op-amp.

Another common way that opamps are used are in comparator circuits. A comparator circuit will compare the voltage on the two inputs and then making the output high or low. This is accomplished by having one input the voltage reference (Vref) and the other input is the voltage input (Vin).



With this circuit you would not need R1, instead this would be your output from the TPS, Using +5V (regulated)for VCC and adjusting R2 to +4V would make it trip where you want it, or wherever you decide to set it. Your output would be between the Emitter of the transistor and the LED. In fact I beleive you could get the +5v and ground via the TPS as the 741 has very little current draw by design. HTH Bob

Info from:
http://home.maine.rr.com/randylinscott/learn.htm
__________________
Bob
84 SVO B234F 16V Volvo head conversion, RPE custom intake, header, FMIC, 38MM BOV, RPE modified diamond pistons, Crower rods, HE351 Holset, 44MM WG/dump, A1000/sumped tank, -8AN lines, T-tops
96 Mark VIII "The overstuffed Cobra" Black/grey, drilled/slotted brakes, FRPP built 4r70W, FRPP converter
RAW Performance Engineering

Last edited by SATURN5; 10-29-2002 at 08:13 PM.
SATURN5 is offline vBGarage Page   Reply With Quote
Old 10-30-2002, 01:16 AM   #3
Senior Member
 
Join Date: Apr 2000
Location: Stillwater, OK
Posts: 1,154
Car: 1991 Formula
Engine: 355 DFI Superram w/ R-Trim
Transmission: Probuilt 700r4

Classifieds Rating: (0)
Send a message via AIM to JMatlock88 Send a message via Yahoo to JMatlock88
Dang, that's perfect! Thanks for the info. I really need to go back and review my electrical science class. I specificly remember failing the op amp question on my final! Now's the perfect time to learn. Thanks for your help. I will let you know what part numbers I can come up with to fit the criteria and the prices. Surely, this can be a cost effective project. Thanks again!:hail:
JMatlock88 is offline vBGarage Page   Reply With Quote
Old 10-30-2002, 08:58 AM   #4
TGO Supporter
 
Join Date: Aug 2001
Location: NJ/PA
Posts: 1,006
Car: Yes
Engine: Many
Transmission: Quite a few

Classifieds Rating: (0)
Just one other thing to add to what Saturn5 showed you. If you are planning to use this to trigger nitrous or some other high current load, you will have to use this op-amp to turn on a FET or Bipolar transistor(which can handle multiple amps). The schematic shows the op-amp turning on and off an LED, which probably will draw something like 10 milliAmps. To properly use this comparator to trigger a switch and not overload the TPS reference voltage, the safest thing would be to use an opto-coupler, to isolate the reference and not overload it. the opto-isolator is wired similar to the transistor, but the 'base' is actually an LED. If you do a search on the internet, you can find all the datasheets you need, as well as some application circuits. Just be careful, since the +5V reference can't handle a large load, and it would suck to have to replace it in the ECM. Hope that helps.
jwscab is offline vBGarage Page   Reply With Quote
Old 10-30-2002, 11:15 AM   #5
Moderator
 
Tim Burgess's Avatar
 
Join Date: Jul 1999
Location: Tucson, AZ, USA
Posts: 1,335
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70

Classifieds Rating: (0)
Here's a schematic using an LM339 quad comparator to do the level sensing for a few WOT detect circuits - there's also an O2 bargraph circuit and a TPS brgraph circuit in the diagram, as well.
Attached Files
File Type: zip o2tpsbar1.zip (56.6 KB, 27 views)
__________________
Tim

1992 Z28, 413 TPI 6 speed, 11.69 sec @ 117 mph

1984 Berlinetta 350 TPI Auto, 11.60 sec @ 120 mph
Tim Burgess is offline vBGarage Page   Reply With Quote
Old 10-30-2002, 11:16 AM   #6
Moderator
 
Tim Burgess's Avatar
 
Join Date: Jul 1999
Location: Tucson, AZ, USA
Posts: 1,335
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70

Classifieds Rating: (0)
Sheet 2 of the schematic......
Attached Files
File Type: zip o2tpsbar2.zip (54.3 KB, 19 views)
__________________
Tim

1992 Z28, 413 TPI 6 speed, 11.69 sec @ 117 mph

1984 Berlinetta 350 TPI Auto, 11.60 sec @ 120 mph
Tim Burgess is offline vBGarage Page   Reply With Quote
Old 01-16-2003, 02:34 AM   #7
Senior Member
 
Join Date: Apr 2000
Location: Stillwater, OK
Posts: 1,154
Car: 1991 Formula
Engine: 355 DFI Superram w/ R-Trim
Transmission: Probuilt 700r4

Classifieds Rating: (0)
Send a message via AIM to JMatlock88 Send a message via Yahoo to JMatlock88
Thank you all for your input. I attached a copy of a circut that came to my head after reading all of your input. Will this design work? I am not sure how to calculate what resistors I will be needing in the circuit and if they will be generating too much heat. I'm also not sure if the op amp will be able to practically trip the 25amp relay and if the LED will light correctly. I would greatly appreciate your comments!
Attached Images
File Type: jpg opamp.jpg (20.3 KB, 119 views)
JMatlock88 is offline vBGarage Page   Reply With Quote
Old 01-16-2003, 10:51 AM   #8
Moderator
 
Tim Burgess's Avatar
 
Join Date: Jul 1999
Location: Tucson, AZ, USA
Posts: 1,335
Car: '92 Z28; Dk Teal; Her Pkg
Engine: 305
Transmission: Richmond 6 Spd
Axle/Gears: Moser 9", Detroit Locker, 3.70

Classifieds Rating: (0)
The 339 is actually a comparator - special case op amp - and it has an open collector output, so it can only sink current (be grounded) when the output is "low" - or be hi impedance (open circuit) when the output is high. You would also need a second resistor from the "-" input to ground to form a voltage divider. Look at the "NOS ENable @ WOT" circuit on the first sheet of my scheatic for a reference.
__________________
Tim

1992 Z28, 413 TPI 6 speed, 11.69 sec @ 117 mph

1984 Berlinetta 350 TPI Auto, 11.60 sec @ 120 mph
Tim Burgess is offline vBGarage Page   Reply With Quote
Old 01-16-2003, 12:32 PM   #9
Senior Member
 
Join Date: Apr 2000
Location: Stillwater, OK
Posts: 1,154
Car: 1991 Formula
Engine: 355 DFI Superram w/ R-Trim
Transmission: Probuilt 700r4

Classifieds Rating: (0)
Send a message via AIM to JMatlock88 Send a message via Yahoo to JMatlock88
Tim, there's only one sheet in that zip file! Thanks!
JMatlock88 is offline vBGarage Page   Reply With Quote
Old 01-17-2003, 10:13 AM   #10
Senior Member
 
Join Date: Oct 2001
Location: Timrå, Sweden
Posts: 930
Car: 1984 Corvette
Engine: Turbo 350
Transmission: 4L80E with TCI T-Com

Classifieds Rating: (0)
This should work.



If you don't need too much curent you can skip the relay and use the wire going from the transistor to the relay instead.
__________________
Jonas Bylund
JoBy is offline vBGarage Page   Reply With Quote
Old 01-17-2003, 12:22 PM   #11
Senior Member
 
Join Date: Apr 2000
Location: Stillwater, OK
Posts: 1,154
Car: 1991 Formula
Engine: 355 DFI Superram w/ R-Trim
Transmission: Probuilt 700r4

Classifieds Rating: (0)
Send a message via AIM to JMatlock88 Send a message via Yahoo to JMatlock88
Woo hoo! Thanks!
JMatlock88 is offline vBGarage Page   Reply With Quote
Old 01-17-2003, 12:22 PM
ThirdGen
1992 Camaro




Paid Advertisement


Reply

Go Back   Third Generation F-Body Message Boards > Tech Boards > Power Adder

Tags
1985, 40, az, burgess, corvette, diagram, engine, header, homemade, install, position, sensor, throttle, tim, tucson
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92


All times are GMT -5. The time now is 02:36 PM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2012, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.5.2
All content copyright © 1997 - 2012 ThirdGen.org. All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of ThirdGen.org's Administrators.

Emails & Contact Details