OK. Heres what I have going on.
I am currently running a stock Bb setup, hood scoop for the tmic, bb ecu, 3" all the way out. Greddy typeS bov (recirc).

First, for some reason I run at 8-9 psi. Dont *** why. Tonight, I noticed that if I let off the gas just a bit, I hit 12-13psi and bog down (Only above approx. 4k rpm).

I think it may be bogging due to the MAF location. My filter/MAF sit right behind my LH foglight. I have ordered a new intake to correct that problem. I have also ordered a Walbro for reasons that I do not have to explain.

I have checked my vaccuum lines, and they all seem to be ok. Any questionable were replaced. The only thing I have breaking them is my tee for the Boost guage (tee'd into line from wastegate to bov), also of new hose.

I think that covers the details. WTF is going on?!?!? Any advice appreciated, Josh

I should add that I do not have my air/fuel or egt installed, yet.

check for IC piping leaks.

Thanks. I know I had one before, so ill check the patch....Josh

Don't tee your Boost gauge into you wastegate line. I would take it off and tee that into the FPR (fuel pressure regulator) vaccum line. Run a solid line from your wastegate to your intercooler pipe. I bet this will help. My buddy had his hooked up like you and it was all wierd too.

NEVER play with that line! if your tee fails, your engine will die fast, painful fuel starved death. leave the boost guage on your wastegate line, i have been doing this for a year, and i havent had a single problem that can be related to it (other than a pinched line, that leaked, and if it had been on my FPR, i would have had to buy a new motor) but it hasnt caused any abnormal driving.

Whats the big deal with Tee'ing into the FPR line? It still runs a lot of fuel pressure even with the line off. Well at idle and while under no load at least....... While under load does it drop dramatically?

yes, under boost, if it doesnt get that boost signal, it wont know to ramp up the fuel pressure to compensate for the fuel fighting the boost to enter the intake manifold.

Tee into the FPR line. That is the best way to get a accurate reading on your boost gauge. As long as you have no leaks in your vacuum line going to your boost gauge from the FPR, then you won't have any problems with your FPR leaning you out. I have ran my sr20det 240sx for a year like this, and have countless other friends with turbo cars that run it into the same spot. NO PROBLEM! Teeing into the wastegate line is most likely why you are boosting more than you should. Other than a boost controller, you should leave your wastegate line alone. Furthermore most boost gauges are meant to read vacuum, and there is no way to read vacuum unless your gauge is tapped in after the TB.

if you have a leak in your wastegate line, the worst that happens is you might make a little more boost, easily catchable.

if you have a leak in your FPR line, you lose a motor, instantly. I know of, personally, 4 SR20s that died an instant, painful death, because of putting a boost guage on the FPR line. proceed at your own risk if you do this.

it only takes one break, and instant death to your motor, just because it has worked fine for a year, doesnt mean it will last forever.

now, if you have the choice between accidentally making more boost or losing a motor, wouldnt you rather gamble the boost? as long as there are no leaks, a boost guage line isnt going to make your wastegate spike any more than having it alone, that millisecond it takes for your turbo to pressurize the line isnt going to make any kind of noticeable spike.

if you are so worried about wastegate interference, then weld on a nipple right after the turbo in the IC piping, this will ensure the wastegate gets its signal as soon and as restriction free as possible. if you end up with less boost, then just turn your boost controller up or put the nipple right after the IC.

you can also use the charcoal canister vacuum line for your boost guage reading. or drill and tap a 1/8th NPT nipple on there.

Well if we are guessing which would be worse then lets lay things out:
-(boost gauge in FPR) If it isn't gettting correct (vacuum/boost)readings then fix it, that is quite obvious and it is probably just a small leak that you can spot, if the line completely pops off that is where you are in trouble, like you said (but better than the alternative?)
-(boost gauge in wastegate line) there you are getting a reading with no vacuum (hard to adjust a BOV without that), and if the line pops off you will max out the little t25 at 18lbs...then it will fall down and hold maybe 14lbs. I don't know about your set-up but too much boost can just as easily ruin a stock set-up motor "I have a couple of friends that have had that happen"

I personally have never heard of any problems with tapping into the FPR althoutgh it makes since that seems like an odd circumstance. You shouldn't be using old vacuum lines on your motor anyways, why add to the risk of a leak with brittle vacuum line. I will leave mine in the FPR because it is the most accurate way to get a good boost reading, i personally want to know exactley how much boost i'm running with as little spike as possible, just like i want to know exactley how much oil pressure i have and egt's i'm running the purpose of gauges to me are to get the most accurate reading possible. I would be more worried about my oil pressure gauge messing up and the plug causeing a oil leak then a vacuum line leaking. But i guess everyone has preferences that work for them. I suggested the FPR regulator because UNDCOVR was having problems with false readings and this is the best way i know to correct them....

Originally posted by lmnhed
Well if we are guessing which would be worse then lets lay things out:
-(boost gauge in FPR) If it isn't gettting correct (vacuum/boost)readings then fix it, that is quite obvious and it is probably just a small leak that you can spot, if the line completely pops off that is where you are in trouble, like you said (but better than the alternative?)
-(boost gauge in wastegate line) there you are getting a reading with no vacuum (hard to adjust a BOV without that), and if the line pops off you will max out the little t25 at 18lbs...then it will fall down and hold maybe 14lbs. I don't know about your set-up but too much boost can just as easily ruin a stock set-up motor "I have a couple of friends that have had that happen"

no no no no no no no no no no no no no no no no no no no no!

how many times must i say this! if you lose signal to your FPR, your engine dies, INSTANTLY. there is no "you see a vacuum leak and fix it" it goes more along the lines of you see a vacuum leak and buy a NEW MOTOR. this is the last time i will repeat myself.

if you leak in your wastegate line, you can see that "hey, my boost guage isnt working" (much like i did once) and replace the broken part. a few seconds of overboosting WILL NOT be as catastrophic as losing fuel pressure, plain and simple. to say that overboosting is worse than a nonworking FPR is just plain stupid.

and if you have some friends that have had that happen, they need to pay more attention to their guages, not noticing a nonworking boost guage and continuing to boost for the considerable amount of time it takes to blow an SR20 up was their fault.

When driving your car, if you look at your boost gauge you'll see vacuum while not under boost if tee'd into the FPR, if your not reading any then something is wrong so you'll know when a line is leaky or not. I have had wastegate line pop off before an i hit 1.3 bar, yeah it wasn't catsropic (sp) but it didn't sit well with me. AS for the FPR way of running it, i see your point but i have yet to meet anyone who has had this problem. ALL my friends tee theres into the FPR and not one of us has had a problem. We have cars that range from a stock talon to a heavily built turbo eclispe. Teeing into the FPR is the most accurate way period. Which is why if you read the first post, it answers his question. But whatever floats your boat, Both side have good points, pick which one you are more comfortable with and stick with it.....

you could easily avoid all this by drilling/tapping a nipple in there, that would be just as accurate, and you wont have to worry about it.

i have, like i said earlier, seen this happen on 4 SR20s, and not a single one survived as a result, whether immediatly, or shortly thereafter. proceed at your own risk, and please, if you tell people they should tee into this, let them know that if it fails, their motor would go along with it, to neglect to tell someone this when you know what might happen would be really wrong of you.

i tee'd mine into the charcoal canister line, and it reads boost just fine, i have never had a problem, and if it ever pops off, MY BOV wont work and i will have a funny idle from there on.

now, if you want the quickest reacting, most reliable signal for your wastegate, you will put it as close to your compressor outlet as possible, if you were truly worried about accuracy, that is where your wastegate signal would go. then, you would put your boost guage/BOV on the intake manifold (i used the charcaol canister line, i dont have an operating EVAP system anyway) and i have a nipple welded on right after the compressor for the wastegate signal.

but hey, im a dumbass, and know nothing about turbos, so dont listen to me.

hell, i dont even own a high powered turbo car, nor have i ever driven one, nor have i ever seen one. neither has Mike Kojima, who first alerted me to this problem.

This is GREAT info guys, I've had my guage tee'd into my fpr line for weeks now and didn't even think about that. I'm going to change it tomorrow. Thanks a motor.

no prob bob.

thanks fellas...Josh

so what is the most accurate way to run all the vacuum lines for your turbo?wastegate into where?bov into where?boost gauge into where?TIA.

turbo will be in next week,can't wait to feel boost!

Originally posted by HotshtSR20
you could easily avoid all this by drilling/tapping a nipple in there, that would be just as accurate, and you wont have to worry about it.

i have, like i said earlier, seen this happen on 4 SR20s, and not a single one survived as a result, whether immediatly, or shortly thereafter. proceed at your own risk, and please, if you tell people they should tee into this, let them know that if it fails, their motor would go along with it, to neglect to tell someone this when you know what might happen would be really wrong of you.

i tee'd mine into the charcoal canister line, and it reads boost just fine, i have never had a problem, and if it ever pops off, MY BOV wont work and i will have a funny idle from there on.

now, if you want the quickest reacting, most reliable signal for your wastegate, you will put it as close to your compressor outlet as possible, if you were truly worried about accuracy, that is where your wastegate signal would go. then, you would put your boost guage/BOV on the intake manifold (i used the charcaol canister line, i dont have an operating EVAP system anyway) and i have a nipple welded on right after the compressor for the wastegate signal.

but hey, im a dumbass, and know nothing about turbos, so dont listen to me.

hell, i dont even own a high powered turbo car, nor have i ever driven one, nor have i ever seen one. neither has Mike Kojima, who first alerted me to this problem.

Where does the factory tap into?

Factory EVAP canister goes into the Intake Manifold I believe.

Ju§tin