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-   -   throttle blip (http://986forum.com/forums/performance-technical-chat/53039-throttle-blip.html)

The Radium King 07-03-2014 02:56 PM

throttle blip
 
so, who want's to build me one of these:

https://classicmotorsports.net/forum/grm/diy-h-pattern-auto-throttle-blipper-set-up-for-the/67068/page1/

it would have to be all electronic (no need for pneumatic as the throttle is electronic and not cable). sensor on the shift linkage, controller, tie-in to throttle signal and brake signal, on/off switch, potentiometer to control amount of blip.

seningen 07-03-2014 03:58 PM

With egas the throttle pedal is just a pentiometer

If more gas lowers the resistance
Putting a relay with a set resistance in parallel would allow for auto blipping

Now all you have to do is create that relay control.

M

The Radium King 07-03-2014 04:04 PM

thinking about it some more, perhaps even the fancy shift linkage sensor isn't required.

it might be as simple as a controller that intercepts the throttle signal at the pedal, as well as the clutch depressed switch and brake depressed switch (with an on/off switch and potentiometer):

on? - no - throttle signal bypass

brake depressed? - no - throttle signal bypass

clutch depressed? - no - throttle signal bypass

yes to all above? - momentary 5v 'blip' to throttle via potentiometer (to control amount of blip)

so, driving along and everything normal. as soon as you brake AND depress clutch the throttle blips for the downshift. only turn on when at the track to avoid parking lot shenanigans.

The Radium King 07-03-2014 04:11 PM

seningen - you're right, logic might not be required - it might be able to be done with relays - relay on the clutch pedal in series with a relay on the brake pedal in series with an on/off switch. if all on then triggers a third relay that pulls the 'blip' resistor into the throttle circuit. the art becomes the duration of the blip (ie, perhaps not for the entire time that the clutch is depressed) and when the blip happens (ie, not immediately when the clutch is depressed, but almost just before the release of the clutch). there are various types of timed relays that might serve the purpose.

JayG 07-03-2014 04:13 PM

Quote:

Originally Posted by seningen (Post 408497)
With egas the throttle pedal is just a pentiometer

If more gas lowers the resistance
Putting a relay with a set resistance in parallel would allow for auto blipping

Now all you have to do is create that relay control.

M

Yes, but the resistance of the potentiometer will vary depending on how much gas you are giving it at the moment, so the circuit would need to lower the resistance bu a specific amount. The problem, is that the value you need would vary depending on the potentiometer value

It could probably be done with an Adruino

The Radium King 07-03-2014 04:17 PM

if you are braking and downshifting into a turn at the track then foot is off the throttle so pedal resistance is a constant. regardless, google is smarter than me ...

AUTO-BLiP Intelligent Downshifts

seningen 07-03-2014 08:15 PM

Quote:

Originally Posted by JayG (Post 408502)
Yes, but the resistance of the potentiometer will vary depending on how much gas you are giving it at the moment, so the circuit would need to lower the resistance bu a specific amount. The problem, is that the value you need would vary depending on the potentiometer value

It could probably be done with an Adruino

If you are not heal toe-ing -- then you will not be on the gas.
You'll have one foot on clutch and one on brake.

Therefore your TP would be at 0%.

Let's say for argument sake that your 0% is 10K ohms and your 100% is 0 ohms.
Then you could throttle blip to 50% with a parallel 10K ohm resistor.

1/Rto_blip = 1 /R(0%) + 1/R(blip circuit)

like others have said -- some sort of timing circuit would be used to
enable the duration of the shunting resistor. An old 555 circuit and a pot
enabling a relay would do just fine.

Mike

jaykay 07-03-2014 08:56 PM

Quote:

Originally Posted by The Radium King (Post 408504)
if you are braking and downshifting into a turn at the track then foot is off the throttle so pedal resistance is a constant. regardless, google is smarter than me ...

AUTO-BLiP Intelligent Downshifts

I need this for my jeep......which is already screwing my driving technique enough as it is!
The pedals are so off plane they are never to be reconciled other than via some gruesome lifter plate monstrosity on the accelerator pedal

Beware that the egas throttle cable disappears into a mysterious cruise control box under the dash. This may be good news as one would have close access to a TPS potentiometer or you could be opening up Pandora's box so to speak

....hmmm think we need to start a good driving shoe group buy lest we release evils of the auto blip!!

The Radium King 07-03-2014 10:36 PM

jk - your pedals are out of alignment because you aren't braking hard enough!

honestly, those dual clutch cars are beasts on the track. they have the advantage on corner entry everything else being equal. manual cup cars and formula cars have throttle blippers for their sequential transmissions. I love heel and toeing, but if that little auto-blip box can give me any kind of an edge then i'll take it.

The Radium King 07-04-2014 06:36 AM

anyone near phoenix? according to their page, potential for a free unit if you let them install it on your car (test on car models that have yet to have tried the device).

thstone 07-04-2014 09:18 AM

Come to LA and I'll spend a day instructing you at no cost so you can heel and toe like a pro! :)

JayG 07-04-2014 10:21 AM

Quote:

Originally Posted by thstone (Post 408576)
Come to LA and I'll spend a day instructing you at no cost so you can heel and toe like a pro! :)

I live in San Diego and am up in LA often. Can I take you up on that?

Paul 07-05-2014 03:51 PM

Our eGas uses two pots to verify throttle position. One runs at half the voltage of the other. If not the DME limits the throttle.

jb92563 07-05-2014 08:15 PM

Sounds like he wants an automatic transmission.:p

The purpose for the throttle blip is matching rpms when downshifting so instead of some predetermined blip rpm, it should really calculate the exact proper rpm hundreds of times per second taking into accoun the decelration rate due to braking and allow you to slam it in gear without clutching at all.

Not sure if the syncro will allow that.

Don't formula 1 cars have something like that?

Interesting idea, lots of room for innovation id say.

thstone 07-06-2014 05:26 AM

Quote:

Originally Posted by JayG (Post 408586)
I live in San Diego and am up in LA often. Can I take you up on that?

Yes, absolutely. Just email me and let me know when you'll be around and let's see if we can meet up sometime. I'll PM you my email address. :cheers:

jsceash 07-06-2014 05:48 AM

Another one for Porsche. While testing a PDK the sales man told me the 2014 rev matchs automatically on down shift on the manuals as well as the PDK.

The Radium King 07-06-2014 08:59 AM

the 370Z has done this for several years, and i'm sure other cars as well. appears easy to do on the e-gas cars, and race cars with sequential manual transmissions have been using mechanical blippers for years. e-gas has the added benefit of, as you note, actually matching rpm (the 370z does this, and i preusme the others). on our cars the downshift into 2nd is a bit more aggressive than into other gears; my local track is all 2nd and 3rd gear so i would just set it up for that downshift. i may just have to ask for an auto-blip for christmas.

shadrach74 07-08-2014 12:42 PM

Quote:

Originally Posted by jsceash (Post 408786)
Another one for Porsche. While testing a PDK the sales man told me the 2014 rev matchs automatically on down shift on the manuals as well as the PDK.


Yes, PDK will match it perfectly every time and shift about twice as fast as I can. It's still not nearly as fun.

I read the Classic Motorsports link and I just don't get the why behind doing this to a manual car. Porsche put a pretty good pedal setup in the car from the factory. Heal and toeing is such second nature now that I don't really think about it. It takes some time to get comfortable with the process, but is really not that hard with practice.

The biggest problem I have encountered is that the ratios in the 6 spd on the S are not consistently spaced, the lower gears are not close ratio at all and the uppers cogs are very close. I often over blip on 4th to 3rd and under blip on 3rd to 2nd.

aussieboxy 07-15-2014 12:47 AM

Auto Blip
 
What happened to the art of driving?

steved0x 07-15-2014 06:48 AM

Quote:

Originally Posted by thstone (Post 408576)
Come to LA and I'll spend a day instructing you at no cost so you can heel and toe like a pro! :)

My problem with heel/toe is this. My brain will not let me lift my left foot off the clutch while my right foot is on the brake.

My heel toe is coming along, but it looks like this:

Clutch in and then brake.
Even though I want to brake hard, I brake more softly than if I didn't have a downshift, because I think my subconscious wants more time.
Move the gear lever.
Blip the throttle, which also usually causes a slight lift on the brake.
Back on the brake as the revs drop.
Then release the brake and get back on the gas as I release the clutch.

Every once in awhile it works out. I am pretty good about not getting a lurch at the end, but I have usually slowed down way more than I want and there is an odd double pulse of brakes most times.

I rode with an instructor in a prepped 996 at Road Atlanta, and to me it looked like he was doing this:

Brake hard.
Then clutch in, blip and move gear lever, clutch out.
Then finish braking, back on gas and go.

I have tried that (not at the track but once I was back home), and found that my left foot simply would not lift off the floor until my right foot was off the brake.

I think I need to sit in the driveway and practice that a few hundred times. But first I need to make sure that I have found the right combo to practice so I don't ingrain any more bad techniques.

So I wish I was closer to LA... but FL to LA is a long way :)

The Radium King 07-15-2014 07:53 AM

decide that you want to slow down - brake using left side of foot.

decide that you should probably downshift to be in the right rpm range:
clutch in.
shift.
roll foot so as to use right side of foot to blip throttle.
release clutch.

decide that you are done braking - release brake.


works best when braking hard so that brake pedal is even with gas pedal; light braking and the pedals are mis-aligned.

steved0x 07-15-2014 09:00 AM

Quote:

Originally Posted by The Radium King (Post 410065)
decide that you want to slow down - brake using left side of foot.

decide that you should probably downshift to be in the right rpm range:
clutch in.
shift.
roll foot so as to use right side of foot to blip throttle.
release clutch.

decide that you are done braking - release brake.


works best when braking hard so that brake pedal is even with gas pedal; light braking and the pedals are mis-aligned.

I will practice that in my driveway. My next track day is at Roebling in September, and (as of the last time I was there) my only downshift is at the end of the front straight, where I go from 5th at around 120 down to 3rd and around 65'ish? Then I run the rest of the track in 3rd, upshifting to 4th before turns 8/9 and getting on the front straight. I believe there is a lot more speed on that track and I am still running the same very conservative pace that I ran on my very first DE ever which was there. I think this time I am going to work on carrying more speed down the short straight and around turn 3 so I may go to 4th and then back to 3rd.

Here is my best lap from last time (where interestingly I was much less than 120 coming down the straight, which is probably why I didn't slow down to 50 or some ridiculous low speed for turn 1):
Track Attack

I have done 1 track day at the firm and 2 track days at Road Atlanta since then so I am interested to see what sort of improvements I have made.

OP sorry that I have hijacked your thread about the auto-blip... to tie it all together I think if I could have had auto blip I could have taken a few seconds off my times at Road Atlanta because I think my corner entry speeds would have been higher.

Thank you TRK for the feedback.

Steve


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