56 replies to this topic

[UltimateLurker]

Edit.

[shift1313]

Thats great, which it was there a couple months ago when i got a little itchy with mine;)  one thing i didnt see is the vac line for the wastegate actuator or mbc if anyone so chooses.  or lines going to the boost sensor on the firewall.  

what exactly is the function of the vac pump, i was eyeing it today.  is that for the heat/ac system?

[UltimateLurker]

There is a vacuum line coming off of the OVCP (over the valve cover pipe) going to the a port on the turbo wastegate, that's where your boost comes from and is not omitable ('86/'87).

On the '88/'89 cars there are 2 other vac lines then coming off of the wastegate actuator going to the 10psi boost solenoid on the aircan.  If you get a MBC (manual boost controller) you'll no longer need those, you just run the OVCP vac line to the MBC, then from the MBC to one of the front ports on the wastegate actuator, plug the other front port with a vacuum cap and leave the rear port (closest to the turbo) open to vent (thanks Mike K.).

The vacuum pump is mostly for the vents, vacuum storage canister, and cruise, if you want these things you'll need to keep it .

[SouthernBoy]

Thanks UL,

Two questions.

1 - Why does the timing retard get connected to the top port numbered 2 when everything is removed, when it was connected from the factory to one of the three ports on the side of the throttle body?

2 - I have tried to leave the charcoal canister connected on my car, although I have removed everything else except the A/C and timing retard.  Should I just forget about that and disconnect those lines?

Thanks for that post UL??

[UltimateLurker]

1. It'll work just fine as the FAQ reads, but if you want to use the 1st port on the TB (farthest from the firewall), you'd be fine having it there as well.

2. I assume you mean the small canister bolted onto the airbox?  It doesn't actually have a vacuum line going to it, it has the Valve Cover Breather/Ventilator line going to it.  Many members have removed this (me included), but many keep it because it's a good system in theory.  However, when the canister gets old/full it blows oil into the intake stream, bad, bad idea.

If you're talking about the Fuel Vapor Filter where the Purge Valve is, again, many remove it, some leave it.  If you can put up with a slight gas smell from time to time (outside), and you're not gonna' be smokin' right beside it...lol, then yeah, ditch it.  I'll get arguments on this one, so just use your best judgement.

[indy_85stariones]

The fuel vapor charcoal canister has been used on cars since the middle 60's.  It is a safety feature.  

Keep the vacuum lines running to the purge control valve.

[87cquest]

I think this def. belongs in the FAQ.  It comes up way too much.  

[marksweet]

Thanks UL,

Two questions.

1 - Why does the timing retard get connected to the top port numbered 2 when everything is removed, when it was connected from the factory to one of the three ports on the side of the throttle body?

I was a confused for a bit until I went back and re-read the RACING ONLY. When racing only the retard function of the diaphram is necessary however the same diaphram on a street car needs to also have a vacuum signal to increase the timing for good part throttle response and  gas mileage so it would need to be tapped into a source that can supply both vacuum and boost as needed. There is no vacuum above the throttle plate. I know you were clear UL but this may help Southern Boy and others that may be slow like me! Mark

[importwarrior]

FROM, KO this is in the FAQ


In the picture below you will see the Vaccume Assembly. Unless you have to have a smog test to pass your state inspection most of these vac lines can go (along with their smog brethren parts) and your engine bay will look a lot neater.

The Secondary air-cleaner assembly (big black box on top of the VC) has to stay unless you have gutted both cats. The EGR (thing under the TB that looks like a flying saucer) has to stay unless you make an EGR cap-off plate for it.

When you are done there should be 1 line running from under the 3 ports on the TB (not shown) all the way around the firewall to the cruise control actuator and to the front of the car where the vac pump is located, leave that one. There should also be 1 line running from the top of the TB where the intake tube meets it, to the vac advance (looks like a flying saucer on top of the distributor), this is represented in red. The blue dots mean cap it off and kill the excess line. If you have or are getting a BOV you will need to hook it to the 3rd port on the TB, show in yellow.

[marksweet]

I'm really confused! How can the distributor pictured from the FAQ "see" a vacuum signal from the red hose?? Thanks. Mark

[UltimateLurker]

Tim: I wrote that, even photoshopped the diagram that came from my scan.  Back when I was making the first vacuum removal FAQ I asked KO how he had his (knowing he was a guru), he had sent me some information detailing it and I made it a little clearer, but it was never clear enough to suit me, this revision settles it...I think ;D.  

Mark: Why ask why? ;D  Trust me, it works, if you're not the trusting sort then just pick another nipple...lol.

[marksweet]

UL I don't need to trust on this as I know the nipple before the TB is fine for a race car but not for the street. The first of the 3 in a row is for a street quest.  Good Luck

[Boosted_One]

The VA needs to run on the 1st port on the TB and here is why.

The vacuum reference is ported for the VA. If you look at the TB the first port has a very small 1/16th hole that is above the throttle plate.

The first port does not see vaccum until a certain rpm range. Take the line off at idle and you should have NO vacuum source from it. Give it a little gas and you'll start getting a little vacuum from the 1st port.

If the VA sees too much vacuum it will advance the timing at idle. So if there is a strong vacuum pull at idle you can bet your timing is getting advanced. If you notice the shop manual does not indicate the VA needs to be plugged to set base timing. This is because at idle there should be no vacuum source from the 1st port to disrupt/advance the base timing.

Mike C taught me this way back in 1996. I bet if you search Ryddlers old archives that post will come up if it goes back that far.

Look at the TB chamber and it shows a lot.

[UltimateLurker]

Wow , thanks mike, excellent info!

[GMpowered]

I wish my printer only worked so i could print this !@#$ out. I got the "Is it normal" post up. I'm new to Jap. cars. I went to school to be a GM tech. When i popped the hood on this car, i was what the !@#$ is all of this crap. These cars got twice as many wires and vac. line than a Vette. I'm just starting to rip some of the pollution crap out. The car is just starting to come back to normal. Before the car would barely move when you put it to the floor. Now it's.....just getting better....LOL. In a couple weeks i'll prob have it to par. And start mod.ing it. I got a old turbo from my cuz last G.N.

[aries2.6]

Vacuum line removal good.  ;D I have a few more questions for you guys. I have this old aries with the mitsu 2.6. Tons of people are telling me that its a crap engine / crap car but hey it says "hemi" on the side and thats funny as hell in itself. Anyways, this car weighs in at 24-2500lbs and the block of the 2.6 is good by all I have heard. The car looks BAD...but with its lightweight and a turbo this thing could theoretically fly right? Can't get more sleeper than a f***** K-car.

I already have a TD05-12a? turbo, stock conquest exhaust manifold on the way. Apparently the wastegate is set at 11-12lbs boost? (conquest turbo) Correct me if I'm wrong. Now I have a few problems with this setup, first is its carbureted, I've looked into going with a blow through carb system and I know I have to have a 1:1 fuel pressure increase so the floats stay full. But what happens to the vacuum stuff? Most importantly, the vacuum advance on the distributor? If its a turbo engine how is the VA supposed to get a vacuum at all? When its boosting (at high rpm) should the timing be advancing with the mechanical advance or with both? At low RPM before the turbo starts to create boost the VA should be advancing right? I guess what I really need to know is what do I have to do to the vacuum advance on the distributor so I can convert this to a turbo setup? Is there any difference? What do I do about the vacuum accessories that need vacuum at all engine RPM like the a/c? What about those vacuum caps to eliminate those other vacuum lines? under boost wouldn't they pop off? thx for any help <img src="http://www.starquest...IR#>/smile.gif" style="vertical-align:middle" emoid="" border="0" alt="smile.gif" />

[KO]

In that case I'll be re-directing my vac. line from the vac. advance I've ran 2 Quest like this for 2 years now without a problem but I'm definitely taking you guys word for it

[chuck641]

alright .. jus so i have this straight in my head.  i have no cats, and i want to keep my heat working.  so i need 1 line going from the 1st port on the tb to the vac advance.  i need the line going from the bottom port on the tb to the vac storage, i have my cruise control removed so can i end the line at the vac storage or does it need to go all the way to the front of the car to the vac pump?  are those all i need?  what about the wastegate?

btw, its an 88 tsi

thanks, Jason

[ZPI28]

This is excellent info, ill clean my engine compartment up some now. Thanks for all the useful info guys..
Steven

[Truth]

i must say that this is absolutely a MUST to do if you do not have any emissions testing in your area.  as soon as i cranked the car up, i noticed a smoother idle.  and the throttle response is awesome when you are going.  i actually noticed the car pulled harder.  great info guys.  ;D