WHY CAN'T I HOLD 15 PSI?!? Another dissatisfied, jaded KA-T owner.

[MarkEmark]

I haven't posted in this forum for a while regarding MY personal problems, but I just can't stand this any more...

The engine is fresh off of a rebuild. Has about 750 miles on it. I spent well over $3600 on this engine, including parts (9:1 wisecos, .020 over, 3 angle competition valve job, 1 mm oversized intake/exhaust valves, PDM stage II cams, etc). Then I upgraded the entire fuel system to handle more boost (JWT ECU, Cobra MAFS, MSD 50 lb/hr top feed fuel injectors, Phat KA-T fuel rail, new fittings, etc).

I know my turbo is small, but it's not THAT small. It's a T3 super 60, .48 a/r exhaust, .60 a/r compressor. I remember a while back AceInHole made some pretty impressive numbers from an even smaller turbo (SR T25).

All that I want is to be able to have 15-17 psi from 3000-6000 rpm. I don't give a crap if the boost falls off past 6000, although ideally it'd stay constant to the 7200 rpm redline....but basically i want at least 15 psi at 6000 rpm, IN EVERY DAMN GEAR.

Here's what happens....In every gear, it'll spike to 12-13 psi right off the bat, but only stay there for an instant. It will immediately bounce back down a few psi and continue decreasing boost, and by 6000 rpm (in 3rd/4th gear) it's at 6, yes 6 psi. That's 1/2 the initial boost the turbo produces, and 10 psi LESS than what I want at the RPM. 10 PSI is a lot of friggin boost to not have, and I can sure feel it.

I've played around with numerous manual boost controller set-ups, using two needle valves, one bleeding air back to the turbo inlet after the MAFS, one bleeding it back to the turbo compressor itself. Right now, a vacuum line comes from the wastegate diaphragm, then there's a needle valve, then after the needle valve there's a vacuum T, with one portion of the T going back to the turbo compressor, one portion of the T going to the turbo inlet after the MAFS, with another needle valve in this line. Before that, there was a vacuum line coming off the wastegate diaphragm, then the vacuum T with one portion of the T going back to the air inlet after the MAFS with a needle valve in this line, and one portion of the T going back to the turbo compressor, with another needle valve in this line. Using this configuration the boost would spike to 15-16 psi at first and fall down to the same disappointing 7-8 psi by 6000 rpm.

I've also tried just using a simiple in-line needle valve between the wastegate diaphragm and the turbo compressor, with no air bleeding back to the turbo inlet. I've also tried a "more precise" JOE P MBC. All set-ups have been equally disappointing. I can't imagine that all these MBC set ups would fail for no reason, and there's no way in hell I'd trust an electronic boost controller after seeing the failure of all my previous set ups.

Now, let me tell you what ISN'T the problem:

I don't think I have a boost leak anywhere. Why? Because my vacuum/boost gauge has perfect, rock solid readings at idle and in gear when the car is decellerating/under no throttle application. If there were a leak anywhere, i'd think the gauge would be erratic at idle and/or when in gear and decellerating with no throttle (correct me if I'm wrong). The only time the gauge is weird is after a long ride when I bring the car back to bring it in the garage, sometimes at the top of my steep driveway the car will stall, but before doing so the gauge will be erratic. But this jumping of the gauge has ONLY happened after switching to my JWT ECU/cobra MAFS/new fuel injectors, so I highly doubt this has anything to do with my boost problem, a problem I've had ever since I turbocharged the engine. It only stalls infrequently when out on drives, and again, has only done so after switching to the new MAFS/ECU. Otherwise, the vacuum gauge says all is good.

It's not the internal wastegate/actuator. Yeah, it is an internal wastegate, and yes, I know internal wastegates are inferior to external wastegates, but I have neither the will nor the money to upgrade to an external set up. A week ago, I was convinced that my stock T3 wastegate actuator went bad. So I went out and bought an extremely overpriced, new GReddy internal wastegate actuator for $110, that was rated at 14 psi AND UP. It was a pain in the *** to make it fit, and it required fabrication. But it fits fine, and I still have the boost problem. Using just the GReddy wastegate actuator with now boost controllers, the turbo wouldn't hold past 7-8 psi, even though it's a 14 psi spring.

It's not the "restrictive" 2.5" exhaust system, because currently, the exhaust isn't even connected. I have a 2.5" mandrel bent downpipe, and at the end of the downpipe is a straight through 2.5" glass-pack functioning to silence the engine a bit. That's it....no muffler, no resonator, nothing.

I can't see or hear of any leak between the head and the exhaust manifold or in the exhaust manifold itself.

Many of you know that this has been a recurring problem with my turbocharger endeavor since the beginning. Before the engine rebuild when I was running less boost, it'd hit 10 psi and then level off to 7-8 psi by 6000 rpm. I can't tell you how unbelievably frustrating this whole problem is....I sunk soooooo much money into the engine and the fuel system to be able to handle the type of boost/power I want it to be able to handle, and it's not making CLOSE to the power I want it to make, because it's barely holding HALF the boost I want it to make.

The ONLY other thing that is "wrong" with the car right now is that the EGR tube, that used to recirculate into the stock exhaust manifold, now has some of that bendable, convoluted ~1" diameter exhaust piping welded onto it, runing down the downpipe and along the transmission where it plugs into a high flow catalytic converter for when I'm going through emissions. The cat obviously isn't there now, so I have this tube plugged right now. Anyway, this tube has recently developed a crack in it right near the downpipe...but this is a recent development; it was fine and uncracked before and the boost still dropped off like crazy, so I'm ruling this out as a possible cause of the insane boost shrinkage.

Can anyone offer ANY insight? I'm at my wits end here...and I don't know how much longer I can put up with this car running at 1/2 the performance I want it to run at...i'm almost contemplating selling it.....

Any help is appreciated, but keep in mind the aforementioned information (this would require reading through the entire, albeit lengthy, post) and don't just respond "sounds like a boost leak"

THANKS!

-Marc
Modified by MarkEmark at 4:21 AM 7/17/2005

[fabio420]

Ok I have 2 insights. First, try an electronic boost controller. Much more accurate and keeps the boost even because of their gain settings. Second, with the work done to the engine, was there any boring on the head or block? I have a similar turbo with but with a smaller compressor housing. Because of the size, you are going to loose boost. It will be an uneven loss if you have an mbc as opposed to an ebc. You get different amounts of boost at different gears in the same rpms. If your displacement is even bigger than stock, then there's a good chance that it's the turbo size. You should be able to reach 14 or even past, but holding it with that turbo is a trickier situation.

[crzycav86]

If the turbo couldn't hold 10 psi at 6000 rpm, what makes you think it'll hold 15?

[Warped]

read it all and you might wanna try a different turbo if you know somone around you that would help you out. i would definately let you borrow my t4 for a few days to see but your not in az

[Nismo_Freak]

It's not the turbo, cause it can support 30#'s of airflow at a 2 PR.

What you should do is first get rid of the manual boost controller crap. You will see better boost response, and better holding at the top RPM. The Greddy actuator that you bought is made for 1.0 kg/cm2, so you will need NO boost controller to hit the 14 PSI you want.

Run it like this, if you can't hit the target boost pressure then you have a turbine energy, or flow problem.

[MarkEmark]

Ok I have 2 insights. First, try an electronic boost controller. Much more accurate and keeps the boost even because of their gain settings. Second, with the work done to the engine, was there any boring on the head or block? I have a similar turbo with but with a smaller compressor housing. Because of the size, you are going to loose boost. It will be an uneven loss if you have an mbc as opposed to an ebc. You get different amounts of boost at different gears in the same rpms. If your displacement is even bigger than stock, then there's a good chance that it's the turbo size. You should be able to reach 14 or even past, but holding it with that turbo is a trickier situation.

I'm really skeptical about electronic boost controllers. Why? Because so many people raved about how good the Joe P MBC was and how, for all intents and purposes, it was as accurate as the $250 electronic boost controllers out there. When I got my Joe P, it worked WORSE than my needle-valve set up. I'm not about to dump $250 into something that I really doubt will cure the problem. We're not talking a 2 psi loss here, which I would attribute to the boost controller(s). We're talking losing 1/2 the initial boost. That's a LOT.

The engine has 9:1 wisecos, bored .020 over, and has had a 3 angle competition valve job along with 1 mm oversized ferrea intake/exhaust valves, and PDM stage II cams.

If the turbo couldn't hold 10 psi at 6000 rpm, what makes you think it'll hold 15?

I wasn't expecting it to hold 15 psi at 6000 rpm...I was expecting it to hold 12-13 psi, a 2-3 psi loss due to the small turbo, like it did when I was running 10 psi (it'd be at 7-8 at 6000 rpm). I think I could live with the 2 psi loss. Not with 6-8 psi! That's theoretically 60-80 hp lost throughout the rev-range. Unacceptable for the amount of money I've spent on the engine and fuel system.

Warped: I'd love to try a different turbo for a few days....I doubt anyone would be willing to do so though...Although, Foster only lives about 40 minutes from me, but I don't want to impose Better yet, I'd just love a ride in Foster's 240 to see what a fully built KA with excellent tuning and a top-notch fuel system SHOULD run.

Nismo_Freak: I'll try getting rid of all the MBC crap and see what it does. I'll keep you guys posted.

By the way, I know I have some blow-by oil from the turbocharger seals in the intake piping due to not running an oil restrictor in the oil inlet line. Could this be affecting it? I'm going to order an ATP restrictor first thing monday morning...

[fiznat]

^^ exactly, what Alan said. Theres no reason to even mess with any of the boost controller stuff right now, because youre running a 14psi spring! Try taking off all the boost control stuff and leaving the work just to the spring, see what that does.

If not, I would really start thinking about going through your charge pipes and looking for either a leak, or an obstruction. Truth be told, I drove my car across down with a freaking rag stuck in my throttle body, and I was still making boost. Not full boost, but the car was acting weird just like you describe. Go through the pipes and see what you can find. Another possability is a bad BOV that is venting when it shouldnt be?

You're so close man, dont give up now! If you cant get things straight by the end of the week maybe I could make a trip to your place and see if I can help?

Stay strong man!

[eh?]

I don't think I have a boost leak anywhere. Why? Because my vacuum/boost gauge has perfect, rock solid readings at idle and in gear when the car is decellerating/under no throttle application. If there were a leak anywhere, i'd think the gauge would be erratic at idle and/or when in gear and decellerating with no throttle (correct me if I'm wrong). Modified by MarkEmark at 4:21 AM 7/17/2005

Why would you see a leak at Vacuum? you have BOOST leak, and the gauge is showing you a leak at BOOST!At idle the vacuum gauge shows you pressure after the throttle body. You don't have a leak there. You have a leak in the IC pipes which will only show in boost. GO get a compressor and leak check your pipes.

[MarkEmark]

^^ exactly, what Alan said. Theres no reason to even mess with any of the boost controller stuff right now, because youre running a 14psi spring! Try taking off all the boost control stuff and leaving the work just to the spring, see what that does.

If not, I would really start thinking about going through your charge pipes and looking for either a leak, or an obstruction. Truth be told, I drove my car across down with a freaking rag stuck in my throttle body, and I was still making boost. Not full boost, but the car was acting weird just like you describe. Go through the pipes and see what you can find. Another possability is a bad BOV that is venting when it shouldnt be?

You're so close man, dont give up now! If you cant get things straight by the end of the week maybe I could make a trip to your place and see if I can help?

Stay strong man!

I tried it out with no MBC, just a short vacuum line from the WG diaphragm to the turbo compressor, and the results are still disappointing....

It spikes quickly to 10 psi, then levels off to 5-6 psi by 6000 rpm...I ran the car in 3rd gear from 3000-6000 with the turnbuckle on the actuator rod both completely extended (to "lower" the boost), and the turnbuckle completely threaded in (to "raise" the boost), and the results were almost identical.

Take a look at the video for a better idea. The first big number on the gauge is 5 psi, the second one is 10 psi.

http://209.245.59.98/Gimme/655...5.AVI

Would a boost leak cause it to spike really quickly to a high psi and then immediately fall back?

[Fenvy]

you can also try to disconnect the vacuum to the wastegate and just run it VERY lightly

I had my share of not boosting higher than it shoudl issue and immediate it went up to 20psi, so be gental on the throttle

[hysteria]

does it seem like your turbo is working really hard? i mean i know what my turbo sounds like at 8 psi and i know what it sunds like when it's spooling without bound (disconnected wastegate)... so basically i know there is a problem when i hear it not spooling enough or spooling way too much.as said before there is no reason for you to be at 6 psi on that turbo if you have a 1 bar spring... my little .48/.42 straight t3 will do the 8 lbs i have it at right now, and it will hold it to readline. does your bov sound normal? usually with a leak the bov won't open up as much, or at all because when you close the throttle all the air escapes through the leak. the vacum gauge isn't a good indicator of a leak... at boost the pressure can cause a leak and then seal up again when you get off the boost.listen to your turbo and tell us what it sounds like... overworking? good indication of a leak. i've seen miniscule leaks cause serious lag and power problems.... my brother had a boost leak for a long time and had no idea... everything worked fine, but he caught it and he got better response, more power, everything.

[grimple1]

my first response was. ... sounds like a boost leak.

Quote »Would a boost leak cause it to spike really quickly to a high psi and then immediately fall back?[/quote]If it was a small enough boost leak, I would think it could.

[MarkEmark]

does it seem like your turbo is working really hard? i mean i know what my turbo sounds like at 8 psi and i know what it sunds like when it's spooling without bound (disconnected wastegate)... so basically i know there is a problem when i hear it not spooling enough or spooling way too much.as said before there is no reason for you to be at 6 psi on that turbo if you have a 1 bar spring... my little .48/.42 straight t3 will do the 8 lbs i have it at right now, and it will hold it to readline. does your bov sound normal? usually with a leak the bov won't open up as much, or at all because when you close the throttle all the air escapes through the leak. the vacum gauge isn't a good indicator of a leak... at boost the pressure can cause a leak and then seal up again when you get off the boost.listen to your turbo and tell us what it sounds like... overworking? good indication of a leak. i've seen miniscule leaks cause serious lag and power problems.... my brother had a boost leak for a long time and had no idea... everything worked fine, but he caught it and he got better response, more power, everything.

I can hear my turbo better than most people because I have no muffler, just a glass pack at the bottom of my downpipe. And no, it doesn't sound like it's working any harder or not as hard as it should be...but I really don't know how much different it'd be sounding if it were indeed working "harder..." I posted a link to a video, but you probably won't even be able to hear the turbo spooling, unfortunately.

I don't know why I'd bother disconnecting the wastegate line, because it'd be extremely hard to regulate throttle so I had 15 psi at 6000 rpm in any gear, and I do not want an engine destroying spike. I guess I could try it though.... I've hit as high as 17 psi before, b ut as you can see with the video, it only hits max boost for an instant, and then immediately falls back and continues to fall.

My Turbo XS BOV (Bypass valve, actually) sounds perfectly normal, like it always has...I can hear it between shifts. I took it out, inspected it, the spring is still as stiff as the day I installed it, it opened and closed smoothly, and there were no holes/tears in the hose going from the hot pipe to the BPV or from the BPV to the turbo air inlet.

I guess the next step is to check every possible area for a boost leak. I'm not sure how I'd go about getting a compressor (what kind of compressor?) and leak checking the pipes? Is there a write-up somewhere? I think i recall seeing some posts about DIY boost-leak checks. I'll do a search.

Watch the video if you guys can, it explains the problem better than I can. Hits 10 for an instant and immediately bounces back...

http://209.245.59.98/Gimme/655...5.AVI

[hysteria]

i have a pressure gauge hooked up to my charge pipes and have a vacuum/boost gauge on the manifold. i basically use the one on the charge pipes to ensure everything is okay... the way the pressure dissipates when the bov opens is very distinct on the gauge... i can usually spot a leak by the way the needle on the gauge moves when i close the throttle. in addition to this even when the car is not at wide open throttle you should be easily be making 10 psi or more in the charge pipes... for instance, my wastegate will open (meaning i have 8 psi in the charge pipes) before my manifold gauge even reads 0 pressure/vacuum... this may further help you determine a leak or whatever, because no matter what turbo you have you should be able to make tons of pressure in the charge pipes at partial throttle... if it falls off after wot, then you have some other problem... not a leak. you could also just build one of those leak detectors people have made on these forums tons of times. take off your pipes and reassemble them, checking everything over, because couplers that have problems will often display these symptoms.give us more info as it comes. hope this all helps. good luck.

[hysteria]

yeah i watched the video, i couldn't hear it at all, which is why i asked what you heard. you can tell when a turbo is working too hard... it sounds much louder than normal, especially if you're working on low boost (1 bar or less).i wasn't suggesting you disconnect the wastegate, it would be hard to regulate, and it's dangerous, because if the turbo spools without bound, a little blip in the throttle can have you at 20 psi in the manifold easily. i was just saying that when i had my wastegate disconnected and boosted it up a little the turbo was overworking a lot and i know what it sounds like, so i can recognize when it works too much.

[toki]

Why would you see a leak at Vacuum? you have BOOST leak, and the gauge is showing you a leak at BOOST!At idle the vacuum gauge shows you pressure after the throttle body. You don't have a leak there. You have a leak in the IC pipes which will only show in boost. GO get a compressor and leak check your pipes.

are you serious? you see a boost leak at vacuum because a "boost leak" is a leak in the vacuum system of the vehicle. Your vac will be lower than normal (lower number) if you have a leak in the system, same way your boost will be lower.

[crzycav86]

But that's only if there's a leak in the manifold. A boost gauge won't be able to detect a leak in the charge pipes... only in the manifold.

[MarkEmark]

But that's only if there's a leak in the manifold. A boost gauge won't be able to detect a leak in the charge pipes... only in the manifold.

I hope to Lord there isn't a leak in the intake manifold, e.g., at the manifold gasket. That'd be a royal PITA to contend with.

I'm going to get a portable air compressor tomorrow (I have a nice big one in the garage but the motor died a few months ago) to pressure test the whole system. First I'm going to pressurize it from the turbo inlet, pressurizing everything, including the intake manifold, as shown by this picture:



Then, I'm going to pressurize just the hot pipes, cold pipes, and intercooler, by blocking off the pipe that goes to the throttle body and adding pressurized air to the hot pipes.

Does the above picture make sense as to what I'm going to pressurize? Or should I disconnect some stuff, such as everything on the turbo inlet and just pressurize the turbo inlet using a dedicated pressure tester (this would eliminate the bypass valve, the hose coming from the valve cover, etc).

[koukiKA240]

i understand what you are pressurizing but one thing confuses me, and thats your vent hose/bov/IACV hose setup. It looks like you are venting the air to your idle control valve and valve cover....or something. The iacv needs to source to the cold pipe just before the TB. The crank vent can source to the atm, it does not have to go back to a pipe, an ur bov will blow off the charged air back just before the turbo and after the MAF. It looks like you have it venting to the IACV/valve cover breather hose.~Sam

P.S. how did u rig up that engine tourque dampener? Is that just the SR unit?

[MarkEmark]

i understand what you are pressurizing but one thing confuses me, and thats your vent hose/bov/IACV hose setup. It looks like you are venting the air to your idle control valve and valve cover....or something. The iacv needs to source to the cold pipe just before the TB. The crank vent can source to the atm, it does not have to go back to a pipe, an ur bov will blow off the charged air back just before the turbo and after the MAF. It looks like you have it venting to the IACV/valve cover breather hose.~Sam

P.S. how did u rig up that engine tourque dampener? Is that just the SR unit?

The reason the valve cover hose is going back to the turbo inlet is because when the car was naturally aspirated, this valve cover hose went into the air inlet right before the throttle body....I realize that I can just throw a breather filter on there but it's been like this for 2 years without a problem. The Bypass valve LOOKS like it's recirculating its air to the valve cover hose/IACV, but it's not, it's recirculating it where it should be recirculated, after the MAFS but before the turbo, in that pipe...it just so happens that there's a barb for the valve cover hose right next to the barb for the bypass valve.

Regarding the IACV, I was unaware that it needed to be connected to the cold pipe right before the throttle body....why? I thought this hose just let more air into the engine (increases the idle speed) when the A/C was turned on? My A/C and defroster work perfectly and blow very cold. I highly doubt that the IACV going into my air inlet is causing any of my severe boost problems, but I could very well be wrong?

Also, I made that engine torque dampener myself. Pretty simple to do. I just got a hatch strut from autozone and found an unused bolt hole on the intake manifold, and voila. The hole on the intake manifold probably isn't strong enough for what it's being used for now, but if it ever breaks/strips, it presents no problem to me....it's a useless hole otherwise.

So is my set up okay the way it is to pressure test everything?

[crzycav86]

Is that check valve on the PCV breather also blocking the air travel from the crankcase to the intake? Or does it only block the oil?

[Kenjim]

IACV must be plumbed into the cold side of your intercooler piping or else it will leak boost out of your manifold...which is probably what is happening. If you have ever taken a look at an IACV valve you will see why it will leak. That idle screw you use to adjust your base idle speed changes the size of a hole (the hole gets smaller or bigger depending on which way you turn that screw) which in turn sets your base idle speed..bigger the hole, higher the idle. That is how base idle is set. Then the IACV solenoid opens and closes another passage to allow additional air in as necessary to maintain its target idle speed. You are leaking your boost out of your manifold through the base idle adjustment hole (that's the best way I can describe it) and back into your intake pipe. Plumb the IACV back into your cold pipe before the throttle body and see if that will fix your problem.

[brunswick240]

Well you might be running into boost problems now, but runnin the car hard (up to 6000 rpms like) with only 750 miles on it is gunna ruin all your seals (correct me if im wrong). But i know that just replacing rings and bearing im gunna have to wait 1000 miles before going over 3000 rpms and changing the oil in between. So maybe you dont have any seals, have you checked your compression? But maybe you should just take it easy on that newly built engine.

[crzycav86]

IACV must be plumbed into the cold side of your intercooler piping or else it will leak boost out of your manifold...which is probably what is happening. If you have ever taken a look at an IACV valve you will see why it will leak. That idle screw you use to adjust your base idle speed changes the size of a hole (the hole gets smaller or bigger depending on which way you turn that screw) which in turn sets your base idle speed..bigger the hole, higher the idle. That is how base idle is set. Then the IACV solenoid opens and closes another passage to allow additional air in as necessary to maintain its target idle speed. You are leaking your boost out of your manifold through the base idle adjustment hole (that's the best way I can describe it) and back into your intake pipe. Plumb the IACV back into your cold pipe before the throttle body and see if that will fix your problem.

And the valve doesn't close when you get back on the throttle? That's some very important info.

[MarkEmark]

IACV must be plumbed into the cold side of your intercooler piping or else it will leak boost out of your manifold...which is probably what is happening. If you have ever taken a look at an IACV valve you will see why it will leak. That idle screw you use to adjust your base idle speed changes the size of a hole (the hole gets smaller or bigger depending on which way you turn that screw) which in turn sets your base idle speed..bigger the hole, higher the idle. That is how base idle is set. Then the IACV solenoid opens and closes another passage to allow additional air in as necessary to maintain its target idle speed. You are leaking your boost out of your manifold through the base idle adjustment hole (that's the best way I can describe it) and back into your intake pipe. Plumb the IACV back into your cold pipe before the throttle body and see if that will fix your problem.

Wow, the n00b comes out strong! If this fixes my problem, Kenjim, you will be my hero, and exalted on the KA-T boards for having your first post not only be in full sentences and actually on-topic, but for helping to fix the problem that has caused the thread in the first place!

Brunswick240: I will correct you, you would be wrong (in some respects). Ask Foster (Fiznat, a mod here) what he did for his break-in procedure on his expensive fully built KA-T engine. Ran it easy for about 30 miles and then made 430 whp @ 20 psi on a dyno. I was a LOT more conservative....I followed fairly strict break-in procedures from Wiseco and from the knowledgeable shop that built my engine. For the first 500 miles I took it very easy. Gradually increasing engine loads and boost (but never exceeding 5 psi...I didn't even get into boost for the first 250 miles) Changed the oil at 100 and 500 miles. There's two competing schools of thought when it comes to breaking in a new engine, and neither is wrong.

The way Foster broke his engine in was the "no-break in" procedure, that is, he pretty much gave the engine hell after 30 miles or so. I followed more of the traditional break-in procedures, varying engine load constantly, never lugging it, never exceeding 3000 rpm for the first 250 miles or so or getting into boost, etc. But yeah, I gave the engine its 500 miles to break in, and if the rings aren't properly seated/sealed by now, they'll never be.

[Kenjim]

Before you go through all the trouble of modifying your piping you could try this first....have someone move the adjustment idle screw almost all the way in (make base idle hole as small as possible or even close it all the way) while you keep the engine alive via accelerator pedal....then go drive your car and see if you can build and hold more boost. Yes, your car will not idle at all with the screw set all the way in but this is just troubleshooting. If this works and you can build boost and hold it, then that is your problem, modify your piping accordingly. If not, then your problem probably lies elswhere. The only downside is that you'll have to reset your idle but that's not that big of a deal.

I also highly suggest pressure testing your piping, you'd be amazed at how many leaks are there that you wouldn't find during idle. But it doesn't sound like you have any leaks big enough that would allow that much boost to leak out...I would imagine that your idle would be totally messed up if you did.

Where did you get your wheels by the way? Or at least, who makes them and what model?

[SSS]

Disconnect the vac line going from the wastegate going to the compressor housing; where you would normally hook that vac line up to the compressor housing connect it to an available fitting in the plenum. Now the wastegate will be reading the TRUE boost pressure present in the intake.Make sure you block the fitting in the compressor housing though.

Get rid of all the manual boost controller crap too.

0.48 AR IMHO is far too small for the KA, absolute minimum should be 0.63.

[toki]

you know frankly im just going to go with what some of these guys are saying, unplug your wastegate and modulate your throttle. Your ECU should be set for 15lbs...and it's a JWT so you know it's WAY conservative, and we are talkin about a built and broken in engine here. If you take it up to 25psi for 2 seconds or something I highly doubt you will explode those pistons.

[eh?]

are you serious? you see a boost leak at vacuum because a "boost leak" is a leak in the vacuum system of the vehicle. Your vac will be lower than normal (lower number) if you have a leak in the system, same way your boost will be lower.

Are you SERIOUS? That's a VACUUM LEAK. Boost leak is AT BOOST. You can have perfect vaccum readings but still have a leak ta boost because of the IC PIPES. Vacuum leaks are post Throttle body. Boost leaks are in the entire air system.

[MarkEmark]

Disconnect the vac line going from the wastegate going to the compressor housing; where you would normally hook that vac line up to the compressor housing connect it to an available fitting in the plenum. Now the wastegate will be reading the TRUE boost pressure present in the intake.Make sure you block the fitting in the compressor housing though.

Get rid of all the manual boost controller crap too.

0.48 AR IMHO is far too small for the KA, absolute minimum should be 0.63.

This is a very good idea...I don't know why I never thought of getting the signal for the wastegate from the manifold pressure....but I will do this.

Also, I'm not even going to bother trying to run the car with the idle screw completely closed; I know my set up is wrong and that the IACV line needs to go to the cold pipe, so that's what I'll do, regardless of whether or not it fixes the boost leak.

Unfortunately, I cannot find anyone who can weld brass to aluminum (my intercooler pipes are aluminum, and the hose barb for the 5/8" hose is aluminum). I think I may just drill and tap the aluminum pipe for a hose barb. Actually, I may not even bother tapping it....I just did a practice test on a piece of aluminum I had lying around, and because aluminum and brass are rather soft, I literally threaded the hose barb into the aluminum...it was a tight fit, but I'm sure it will be leak-proof, especially if I use teflon on the thread and JB weld to seal around the fitting.

I'll keep you all posted.