Decreased fuel efficiency after rats nest removal?

Eatmyclutch · 05-16-2008, 10:50 PM

Pics of what I have removed so far.
Port? vaccums

White circle denotes removal of hose

^^^ 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

Quote:

Originally Posted by phoenix7

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:

Then connecting it to the second port:

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.

05-16-2008, 10:50 PM	#1
Eatmyclutch business as usual Join Date: Apr 2008 Location: Emerald City Posts: 154 Rep Power: 0	Decreased fuel efficiency after rats nest removal? Pics of what I have removed so far. Port? vaccums White circle denotes removal of hose ^^^ Removed two lines I also removed the two lines next to the dizzy __________________ Bitch

05-17-2008, 12:41 AM	#7
Eatmyclutch business as usual Join Date: Apr 2008 Location: Emerald City Posts: 154 Rep Power: 0	Nah, I plugged all. Is that what is causing decreased mileage? How do I correct this? __________________ Bitch Last edited by Eatmyclutch; 05-17-2008 at 12:44 AM.

05-17-2008, 06:44 PM	#8
Eatmyclutch business as usual Join Date: Apr 2008 Location: Emerald City Posts: 154 Rep Power: 0	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: Then connecting it to the second port: __________________ Bitch

05-18-2008, 02:25 PM	#9
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan Posts: 530 Rep Power: 18	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. __________________ "Learn from the past, or it will become your future...." '85 GS 12a + LSD/Sterling carb/Respeed coilovers/Respeed front swaybar/Respeed adj. rear spring perches/Illuminas/Bilsteins on rear AutoX vids @ http://www.youtube.com/user/Kentetsu1

05-19-2008, 06:56 PM	#10
rx7carl Rotary Fan in Training Join Date: Mar 2008 Location: Orlando, Fl Posts: 59 Rep Power: 18	Not having the ign advance is probably why your mileage dropped. Ken isint the forward port manifold vacuum? __________________ www.pbandjracing.com

05-16-2008, 11:39 PM	#4
WE3RX7 RCC Addict Join Date: Feb 2008 Location: VA Posts: 1,812 Rep Power: 19	^ No longer having to worry about passing emissions, lol.

05-16-2008, 11:58 PM	#6
orion84gsl Rotary Fanatic Join Date: Mar 2008 Posts: 167 Rep Power: 18	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.

05-20-2008, 04:31 PM	#11
Kentetsu RCC Contributor Join Date: Feb 2008 Location: Grand Rapids, Michigan Posts: 530 Rep Power: 18	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!

05-22-2008, 10:04 AM	#12
rx7carl Rotary Fan in Training Join Date: Mar 2008 Location: Orlando, Fl Posts: 59 Rep Power: 18	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. __________________ www.pbandjracing.com

05-22-2008, 08:15 PM	#13
Eatmyclutch business as usual Join Date: Apr 2008 Location: Emerald City Posts: 154 Rep Power: 0	^^^ 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. __________________ Bitch

05-23-2008, 04:08 AM	#14
orion84gsl Rotary Fanatic Join Date: Mar 2008 Posts: 167 Rep Power: 18	I've never experienced any low RPM hesitation that wasn't directly related to shoddy footwork.