I'd like to add a button to my car to blip the throttle for me on downshifts. I've had a few operations on my right foot and I can't really heel to toe any more.

I've seen this done before with an air system but it seems to be that it should be possible on the C5 electronicly since the throttle is controlled by the computer. For safety, I believe you could use the clutch starter interupt switch to prevent the blip if the button is pushed with the clutch engaged.

I'm not sure if you could do something with a modified program for the PCM or if you could go external and piggyback on the existing system. Working with a modified PCM would be ideal and safer.

Anyone have a tuner to recomend or any comments?

Thanks!

Mike

 

Sounds like a great idea, I just dont think it can be pulled off. If you have the money, a 360 modena or a F430 both both blip the throttle upon downshifting, and they come with paddle shifters. I would leave the vette for one of those if I could afford it and was in your situation.

 

Oh, it's possible. The real question is if it's practical.

I'm putting in an air system in my race car but that's a little more straightforward.

Mike

 

May not be what you want to hear........ but some of us race with an A4


DH

 

I think the throttle is controlled through the ECM, not the PCM, and the ECM controls the TAC. However, there IS a little red folder in my Commercial Version of EFILive that is named ETC for electronic throttle control. The folder is red because they say that you can render your PCM useless by entering incorrect values in there. You may want to jump on the EFILive forum and talk to them about this. They are probably the best at what they do with the PCM and if anyone can do it they might be able to find a way.

 

It would be very easy to jump in the middle of the eclectic throttle motor and blip it open. The problem is with the fly by wire system there is lots of system checks to be sure something don't go wrong like stuck throttle or component failure. The first time the systems sees the throttle plate move when it didn't command it to move, the system will shut down. With that said, I'm sure a device could be built that could be inserted between the throttle position sensor and throttle motor which would monitor the throttle position and blip open the throttle with electric throttle motor while feeding a fake throttle position back into the system so it would stay happy. But messing with the fly by wire throttle system could be a dangerous thing!

 

The simple answer is not easily…

The throttle position sensor is paralleled and feeds both PCM and throttle control module. Then the active handling/traction control module sends a pulse width modulated signal at 100 HZ to throttle controller which is used to reduce power beyond what PCM is asking for.

So basically you have two modules commanding throttle angle. This is from memory but if you need additional info I can dig it up.

As I said reducing throttle angle is much easier, then increasing it.


Mike

 

how does the pcm read the signal from the throttle pedal? could you mimic the signal before it gets to the pcm? if i knew more about the way it works maybe i could help with the circuit

 

I’ll dig up diagram tomorrow and post. Pedal is similar to throttle position sensor (TPS), 5V reference and acts as voltage divider (pot, 3 wire connection... 5V, signal and ground).


Mike

 

Ahhh, great info!

I figured that it would be difficult to piggyback due to the redundancy and feedback for the throttle. Working through the computer was my first thought but working from the throttle pedal forward seems to also be an excellent idea although it may have the same issues as externaly commanding the throttle plate.

We (LapTrax) have the capability to produce hardware and software to do this if we can figure out how.

I look forward to hearing more!

Mike

 

holy moly! i just checked out your site...shouldn't we be asking you how to do this? wow..im impressed!

 

PM me your email and I’ll send a PDF that describes operation fairly well. It’s late gotta sign off.

Oh, in thinking more about it, throttle (pedal) based operation is lowest risk with little to no chance of throwing codes or upsetting associated modules.


Mike

 

The electronics would be fairly simple, but the safety would be my concern. The best I remember the pedal contains three pots, two swings up and one swing down. GM makes sure that something don't go wrong in the fly by wire system by using multi sensors (on the pedal and throttle plate). The first pot will do the work, the second one will make sure the first one is still working correctly, the third one will make sure the second one is still watching the first one. If anyone of these fails the system will shut down to prevent an uncontrolled throttle. Even if the throttle blade sticks the system still has control over fuel and timing, it can still shut down. You will have to intercept all three signals from the pedal and fake them to the system. Once YOU intercept these signals YOU have defeated GM's safety checks and it is 100% up to YOU to be sure something don't go wrong in YOUR electronics and send a high powered Corvette WOT with no control because YOU don't have control of the entire system like GM does. That is why I say messing with the fly by wire electronics can be very dangerous!

 

Thanks for the information, compliments and advice! PM sent for more info.

SpeedyZ, I hear what you're saying. I won't do this if I'm not confident that it can be done safely.

Allways remember... if the throttle sticks open, the clutch is your friend!

Mike

 

Wonder if you could just use an electronic solenoid to create a vacuum leak? Maybe even a nos solenoid? Guess you would have to plumb the inlet to draw air from after the MAF... no biggie?

This would prob be cheap too - lowes has pipe thread nipple fittings and grab some vac hose...

Just might work? Wonder how big the line would need to be to rev to say 4k? That might be the only problem. I know the port on the pass side of the intake manifold right behind the tb is a decent size...

If you need more airflow to get a higher rpm maybe you could find a bigger solenoid and tee into the power brake booster line?

Add a little pulse width modulation to vary the solenoid - this could get crazy...

 

Here check out these valves...

http://www.stcvalve.com/Process%20Valve.htm

 

Those are some beautiful wheels!!!!

 

Just had a chance to revisit this. I was chatting with a friend today and he had what I think is a better and simpler idea...

He suggested simply adding relays to switch out both signals from the throttle pedal to a fixed value or one set by a pot. I guess people messing with electric and hybrid cars have been doing this for applications such as cruise control and other hacks.

It seems simple enough. The switchover can be buffered by a capacitor if needed.

Thoughts?

Mike

 

that was i was thinking as well, i havent had a chance to go over the technical aspects of it though (work is crazy) I have to think about the safety's put in the system though. so we know what needs to know what.

btw..
thanks torqued84

 

that was i was thinking as well, i havent had a chance to go over the technical aspects of it though (work is crazy) I have to think about the safety's put in the system though. so we know what needs to know what.

btw..
thanks torqued84