where to tap?

[napkinthief]

Ive been reading around a lot, looked through about 2 pages of search, and read all the turbo installation guides on the tech, where do I tap the 420a for a boost gauge??? The closest I got was this, but it looks like a 4g63 not a 420a

http://www.dsmtuners.com/forums/showthread.php?t=205099

 

[oldman]

The best place to tap for boost gauge is any direct pressure source off the intake manifold, can't tell you more as I'm not familiar with the 420a.

 

[wolf20043]

I would say You would be ok to tap it into the vacuum lines coming from the back side of the intake mani. As oldman, said as long as it is after the tb it should work.
Mike

 

[DSMcrazy3]

Here's a pic of the port furthest left on the intake manifold. Most seem to tap one of the two I cirled in yellow.(The middle one that I didn't circle is for cruise control.)

You must be logged in to view this image or video.

For 96 and above models, the line for the FPR will actually be going to the AC compressor. Thanks Selmerguy

 

[XMasta19]

I tapped off the brake booster ( fattest line off the intrake manny) ... no probs

 

[napkinthief]

Just above the throttle plate there is a rubber elbow then a plastic line running from behind the throttle body all the way to the passenger side, did not follow it past there its noticable though. I poked a hole there and stuck the tube I have in then hot glued over it seal it. My gauge reads -30 vac idle, but with some throttle it goes to -20. The gauge sits at -18 with nothing connected. Is it broken?

can someone link me to that 420a engine compartment guide or whatever its called, been looking for it cant find it

 

[napkinthief]

got the engine guide


2gnt Engine Bay tutorial ---i was searching for 420a engine guide
http://dsmtuners.com/forums/showthread.php?t=100294

 

[napkinthief]

http://dsmtuners.com/forums/attachment.php?attachmentid=23607&d=1075591570

follow the top yellow line of the box left and you see a cap. On my car there is a rubber elbow there, with a long hose going to the left. I tapped at the elbow. I dont understand how this guy has his capped. When I put my finger over mine with the elbow off, the engine dies.

 

[selmerguy]

Just above the throttle plate there is a rubber elbow then a plastic line running from behind the throttle body all the way to the passenger side, did not follow it past there its noticable though. I poked a hole there and stuck the tube I have in then hot glued over it seal it. My gauge reads -30 vac idle, but with some throttle it goes to -20. The gauge sits at -18 with nothing connected. Is it broken?

can someone link me to that 420a engine compartment guide or whatever its called, been looking for it cant find it

i would not tap there. that goes through the tb. tap one of the lines that are on the mani. buy some tees and cut the line inhalf and there you go. too easy.

 

[wolf20043]

i would not tap there. that goes through the tb. tap one of the lines that are on the mani. buy some tees and cut the line inhalf and there you go. too easy.

What He said. I would T it into the one circled in the pic above labled EGR.
Mike

 

[napkinthief]

Ok Will do, fiberglassing it into my dash right now gives me time to search through the darkness for these lines.

Is the gauge broken because it reads -18 with no pressure? or uncalibrated or something?

 

[wolf20043]

Ok Will do, fiberglassing it into my dash right now gives me time to search through the darkness for these lines.

Is the gauge broken because it reads -18 with no pressure? or uncalibrated or something?

With nothing connected, It should be at 0 I would think.
Mike

 

[cs82685]

Ok Will do, fiberglassing it into my dash right now gives me time to search through the darkness for these lines.

Is the gauge broken because it reads -18 with no pressure? or uncalibrated or something?

Is anything hooked up at this point? If you've got your power and ground already hooked up but no vacuum source yet then when the car is on you should be at or near zero. If you do have the boost gauge hooked up to a vacuum source then when the car is on you should have a negative reading.

ALso, you obviously don't have cruise control which is why that 3rd port on the manifold is just capped off, you can use that for anything that you need a vacuum source for, however i would prioritize. Fuel management should be first b/c if you have a weak source for that say goodbye to your engine. I would say BOV next to protect your turbo from compressor surge. THen find a spot for the boost gauge.

Also, if you are going the route of cheating to avoid small boost leaks and hook up the vac line from your wastegate to the manifold instead of from the wastegate to the turbo, that should also take priority over the boost gauge. A good working wastegate that you know is set at say 5 or 7 psi will provide that amount to the engine if you go this route and you can be confident of how much boost the engine is seeing without the boost gauge being as accurate as possible because it is farther away from the manifold. However this way also prevents you from noticing those boost leaks until they are too big.

Very important, the line coming off of the manifold on the left side has an extra port on it if you follow the line, but do not use this port or put in a T after it because the results will be not good. I forget exactly what its for, but i know there is a check valve in the line where that port is so if your going to T off of that line go between the manifold and the port that is already on there.

 

[selmerguy]

the check valve he is refering to is on the line going to the ac compressor. it is in the plastic tee that is already there. don't use that tee for anything either.

 

[napkinthief]

Is anything hooked up at this point? If you've got your power and ground already hooked up but no vacuum source yet then when the car is on you should be at or near zero. If you do have the boost gauge hooked up to a vacuum source then when the car is on you should have a negative reading.

ALso, you obviously don't have cruise control which is why that 3rd port on the manifold is just capped off, you can use that for anything that you need a vacuum source for, however i would prioritize. Fuel management should be first b/c if you have a weak source for that say goodbye to your engine. I would say BOV next to protect your turbo from compressor surge. THen find a spot for the boost gauge.

Also, if you are going the route of cheating to avoid small boost leaks and hook up the vac line from your wastegate to the manifold instead of from the wastegate to the turbo, that should also take priority over the boost gauge. A good working wastegate that you know is set at say 5 or 7 psi will provide that amount to the engine if you go this route and you can be confident of how much boost the engine is seeing without the boost gauge being as accurate as possible because it is farther away from the manifold. However this way also prevents you from noticing those boost leaks until they are too big.

Very important, the line coming off of the manifold on the left side has an extra port on it if you follow the line, but do not use this port or put in a T after it because the results will be not good. I forget exactly what its for, but i know there is a check valve in the line where that port is so if your going to T off of that line go between the manifold and the port that is already on there.

Thanks for all this info, but what are you talking about? First of all, the pic is not of my car, it is the one from the 2gnt engine bay guide. Second, that capped off line, accoridng to you is no cruise control, I dont have cruise control, but my line is definetly not capped off. I will take a pic for you tomorrow.

I am doing everything I need to install my turbo step by step. First I am doing the gauges. The fuel pump and the FMU will go in when I am done with the gauges. Next I will fabricate a location and bolt in the intercooler. I will now have to make the intercooler piping that will fit. Then I will finally install the turbo, manifold, and intercooler piping. The bov will go on the intercooler piping.

The boost gauge is here to make sure that I dont go over my boost amount, and to make sure I am boosting the amount I want to be. I am not buying a brand new turbo with a pre-calibrated wastegate set to 8psi. I will be getting a turbo, modifying the wastegate to let off when I want it to and a boost gauge is a good method of doing so.

 

[cs82685]

Thanks for all this info, but what are you talking about? First of all, the pic is not of my car, it is the one from the 2gnt engine bay guide. Second, that capped off line, accoridng to you is no cruise control, I dont have cruise control, but my line is definetly not capped off. I will take a pic for you tomorrow.

Sorry I said it was cruise control b/c someone earlier said that's what it was for, if yours is not capped, then I'm sorry I can't tell you what it's for, I just know the one in the picture is capped and mine was too.

The boost gauge is here to make sure that I dont go over my boost amount, and to make sure I am boosting the amount I want to be. I am not buying a brand new turbo with a pre-calibrated wastegate set to 8psi. I will be getting a turbo, modifying the wastegate to let off when I want it to and a boost gauge is a good method of doing so.

In that case tap the boost gauge as close to the manifold as you can, what i was saying was just another suggestion if you had a wastegate you didn't have to modify (ie from hahn turbo kit or star kit) I'm lazy and have small leaks i don't want to deal with so that's why i hooked my wastegate up to the manifold and to me in that case it takes priority over my boost gauge.

 

[selmerguy]

oh also i just looked at the pic that dsmcrazy3 posted and if you have the newer fuel system 96+-99 then the vac lines does not go to your fpr. the vac lines go lie this: ac comp, cruise, egr. i would tee into the egr line if i was you.

 

[DSMcrazy3]

oh also i just looked at the pic that dsmcrazy3 posted and if you have the newer fuel system 96+-99 then the vac lines does not go to your fpr. the vac lines go lie this: ac comp, cruise, egr. i would tee into the egr line if i was you.

Good catch, I forgot about the FPR, I'll edit that into my post above. Thanks

 

[XMasta19]

blah blah blah....use the brake booster line like that guy said earlier

 

[napkinthief]

Ok I tapped the line leading out left from the manifold, my gauge reads -18 on off, then drops to -30 at idle, then around 20 at WOT, I think it needs to be calibrated or something it is -18 off

and while doing, I kinked 3 lines which I had to run down to autozone for twice. Third time I just stayed there till I got it to work.

as of right now, the vaccuum tube is run through a hole in the firewall under the passenger feet carpet, then around the center console, infront though , and up into my gauge cluster where I got my gauge

 

[DSMcrazy3]

The gauge should read 0 when the car is off, and without boost, at WOT it should read 0 as well.

I don't believe they can be calibrated. It happened to me, so I just trashed it and got a new one.

 

[selmerguy]

The gauge should read 0 when the car is off, and without boost, at WOT it should read 0 as well.

I don't believe they can be calibrated. It happened to me, so I just trashed it and got a new one.

x2 happened to me too. stupid obx gauges.... autometer is #1

 

[XMasta19]

umm..I've got an AutoMeter and mine went bad faster than woah. I drove my car with boost like umm, one night. It managed to sit at like 2psi when off by the time I got my car running now. I talked with AutoMeter about it...they said to ship it to them and they'll repair or replace it. meh...I don't feel like shipping it out to them. I think I'm gonna get an AC Autotechnic S7 Invision, and the boost sensor for my zeitronix

 

[DSMcrazy3]

x2 happened to me too. stupid obx gauges.... autometer is #1

Mine was autometer, I just got a new one.

 

[napkinthief]

Well it was reading wrong so I decided to pull it from the car and try to take it apart. DAMN thats glued on there tight. I realized how I can change the needle position though. I took a pen and put pressure on a golden inner ring on the gauge. The trick is to get to -30 vac if you are in boost when the gauge is off, or +30 boost if you are in vac when the gauge is off. Then apply a little more pressure and the needle will only go back how much it went to get to 30.

That seems confusing to me even though I wrote it, heh. Heres what I did. I was in -18 vac. I pushed the needle into 30 boost by applying pressure on the inner gold ring. Then I theoreticlly made it go to 48 boost, then let go. so the needle only goes back 30, which end it up on 0.

Of course I had no clue waht I was doing and made it go deeper in vac at first, then into boost and had to work slowly towards 0.

Now at idle, my gauge reads -16ish, at WOT its at 0, and off its at 0. could -16 mean I have a leak in my line somewhere or what kind of engine problems would show bad vac readings?