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-   -   what's a dashpot for? (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/whats-dashpot-19237/)

HENRX7 09-05-01 09:57 AM

what's a dashpot for?
 
just curious.:rolleyes:

rxspeed87 09-05-01 11:35 AM

a dashpot is supposed to slow down the throttle right before it closes all the way, in doing so your car does not run really rich for a moments and possibly stall the car.
but from what I understand also b/c your car does run rich for a moment and you are running straight pipes and muff you should get some good flamage.
even though I had ful stock exhuast I took my dashpot off cause I liked the crackle it would give for the moment I let off the exhuast

Scott 89t2 09-05-01 12:51 PM

hmm, I never thought about how the dashpot would stop flames but it makes sense. I should go loosen mine ;)

basicly the dashpot is like a cushin for the throttle plates. when you let off the pedal fast. the plates slowly close when they get almost to the end. it helps prevent bucking when you let off and makes the car drive smother.

HENRX7 09-05-01 01:08 PM

kewl, so no dashpot = :devil: !!!

rxspeed87 09-05-01 01:15 PM

the only time it really seems to help for making the car drive smoother is in first gear other then that who cares about a little jerk when you let off the throttle.

should I be able to shoot flames now that I have a header and DP? still have the stock cat back though

SpeedRacer 09-05-01 02:36 PM

Most likely not...I have a racepipe with stock mufflers, and I get no flamage...But then again thats probably saved me from several tickets, so I'm not too worried about it.

copandengr 09-06-01 08:42 AM

Dashpots
 
Dashpots are there for much the same reason as turds being tapered on the end. They keep your asshole from slamming shut.

A dashpot keeps the throttle from slamming shut. The last bit of throttle travel is slowed by the dashpot so that is closes slowly.

Josepi 09-06-01 09:05 AM

I thought they slow the throttle drop down as to make for a smoother ride. Oh well.

Smoke 09-06-01 05:37 PM

Boom!
 
I have heard that the dashpot can prevent an engine from blowing. I know of a guy who was flooring his and he let off the gas suddenly when he saw a cop and boom there goes the engine. No the question is this, by him removing the dashpot cause that? I can see why it could by cutting off air when it is needed but at the same time I have blown an engine that way with a dashpot but mine had been going for quite sometime it was going to happen some day! Just a thought!

bottomfeeder 09-06-01 05:49 PM

Can somebody please tell me where the dashpot is located. I don't think mine is working??? THANKs

Smoke 09-06-01 05:57 PM

Where?
 
If you are standing in front of the car it is facing you on the front of the throttle body. Well this is for an N/A there is a vac hose going the thermo pellet. It looks like two bowls stuck together with an arm sticking out of the middle. I know that is a sucky idea if the car is turbo I believe it is on the other side considering the throttle body is turned around on those.

bottomfeeder 09-06-01 06:43 PM

Thanks Smoke I think Ive found it. Could somebody tell me how to test it.

Smoke 09-06-01 07:18 PM

Testing
 
You test them with a hand vac pump. I don't have the specs with me at work but I can get them to you tomorrow on what to set it to. Putting a vac pressure on it will test the diaphram inside. Basically open your plates manually and let go and see if the dash pot slows the plates from slamming shut.

bottomfeeder 09-06-01 08:48 PM

Thanks Smoke you the man .....

C. Ludwig 09-06-01 08:54 PM

The dashpots may have had an emissions purpose also. Some, more modern cars (my Contour SVT for one) has a noticeable throttle hang when chopping the throttle. The cause is the injection programming that opens the equivalent of the BAC (IAC in Ford speak) and lets RPM fall less rapidly. The theory is that a rapidly closed throttle will prevent fuel that's already injected from being burned properly. The feeling when driving the car is that of a very heavy flywheel. Don't know if that was Mazdas intention, but it's a thought.

Chris

rlynchster 11-22-21 08:17 PM

I know bringing up an old thread is bad .. . . But heck, I made it here.

Here's the thing with the dashpot that nobody here seems to get. It's only purpose is this: . . . When you come to a stop in a rapid fashion by a traffic light, and you push in the clutch to do it, you are no longer on the gas pedal so the throttle body plates go into a rapid closed position. At this point, the ECU realizes it has no air, but it still has to manage an idle. The result of this condition is that the engine might want to stall, or dip too low in rpms before it catches up, which causes the ECU to overshoot and raise RPM's. This condition can cause a wobble rpm cycle, or worse yet, stall.

Your bumper to bumper on the freeway, and have to do a 30mph stop to nothing, and you have to mash the clutch and brake, you want a dashpot to slowly bring the last RPMs down cause you ain't on the throttle and your ECU is the fastest 80's tech available.. . . A little mechanical dashpot help wouldn't hurt as it slowly closes the throttle plates and helps the ECU find idle under a fast changing condition.

If your car is out of tune, this thing also helps with ensuring your car does not stall when you are fingering it in the garage.. . . You lucky devil.

Removing this thing gives you nothing. . .Having it gives you better drivability.



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