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View Full Version : Decreased fuel efficiency after rats nest removal?


Eatmyclutch
05-16-2008, 10:50 PM
Pics of what I have removed so far.
Port? vaccums
http://i25.tinypic.com/rsy4h2.jpg
White circle denotes removal of hose
http://i27.tinypic.com/2ntv8z7.jpg
http://i26.tinypic.com/avscyh.jpg
http://i25.tinypic.com/2py6gs2.jpg
^^^ Removed two lines
I also removed the two lines next to the dizzy

Phoenix7
05-16-2008, 10:54 PM
what are the benefits of the rat's nest removal?

85rx-7gsl-se
05-16-2008, 10:57 PM
Less stuff to worry about, cleaner engine bay.

WE3RX7
05-16-2008, 11:39 PM
^ No longer having to worry about passing emissions, lol.

Eatmyclutch
05-16-2008, 11:39 PM
what are the benefits of the rat's nest removal?

Less emissions equipment.

orion84gsl
05-16-2008, 11:58 PM
It can't break if it's not there. "IF" I'm seeing this right, and that's a big IF, then it looks like you didn't hook the vacuum advance back up.

Eatmyclutch
05-17-2008, 12:41 AM
Nah, I plugged all. Is that what is causing decreased mileage? How do I correct this?

Eatmyclutch
05-17-2008, 06:44 PM
This is what it looks like now.
Alright just went to the store and bought a T fitting, connecting to the advances on the dizzy:
http://i28.tinypic.com/uadkw.jpg
Then connecting it to the second port:
http://i30.tinypic.com/334qlq1.jpg
http://i27.tinypic.com/259itro.jpg

Kentetsu
05-18-2008, 02:25 PM
Connect it to the farthest port forward at the base of the carb. This will start advancing the ignition as soon as you start giving it gas. The original setup would retard the ignition (possibly) for emissions purposes, but this is not what you want. You want it to advance when you give her the go juice. More torque, better gas mileage, more fun. :)

rx7carl
05-19-2008, 06:56 PM
Not having the ign advance is probably why your mileage dropped.

Ken isint the forward port manifold vacuum?

Kentetsu
05-20-2008, 04:31 PM
If it is, then all my theories just flew right out the window. :) I'm pretty sure that it is ported vacuum. I did some hands on testing last year, and uncapping that port at idle had no effect while uncapping most of the others affected the idle. Based on that, I figured that it was ported vacuum (it did draw once you tipped into the throttle).

If I am mistaken, please correct me before I continue to spread this sort if disinformation. Thanks Carl! :)

rx7carl
05-22-2008, 10:04 AM
As I recall from the FSM. M/T cars use the second port (ported vacuum) and A/T cars use manifold vacuum. Now heres the rub. The solenoids that control the vacuum that goes to the dizzy and it works differently on A/T and M/T so Ill just focus on the M/T cars. Vacuum isint allowed to the dizzy right off idle by the solenoid. I think thats so you dont get a big advance off idle which might cause a hesitation, frankly I dunno why they did it that way, emissions?. IIRC after 1200 rpm's the solenoid opens and then you get vacuum to the dizzy. Also under decel I think it closes off the vacuum below 1200 rpm. So when you remove the solenoids the timing will still be fine but you might have a slight hesitation, though Ive never experienced that.

Eatmyclutch
05-22-2008, 08:15 PM
^^^ Thanx. A/T sports cars should be illegal anyway.

I've encountered some hesitation so far, I figured it'd be time for spark plug replacement.

orion84gsl
05-23-2008, 04:08 AM
I've never experienced any low RPM hesitation that wasn't directly related to shoddy footwork.