JDB Posted April 13, 2012 Report Share Posted April 13, 2012 ...the psi gage/supercharger. My gage reads 0 and virtually never moves. Yes I understand it's when you get on it, but I get on it! As a test, on an uphill on-ramp 0-70mph hard, I got the gage up to 3 at best. It's also the only time I hear the supercharger, which even then isn't that loud (not nearly as loud as the multiple youtube vids I've seen, including that in-car at Sears Point). At idle and fast starts in-town I don't hear the whine or see the psi gage move one bit. At idle with the hood up, nothing but motor. I seriously hear the clutch hiss 10x more than any supercharger whine. So what is it: newbie? useless gage? something broken? should've bought vapor? Link to comment Share on other sites More sharing options...
09vistablue Posted April 13, 2012 Report Share Posted April 13, 2012 How many km's on the vehicle ? you have to drive a number of consecutive km's to unlock the computer to allow full boost. Also the gauges aren't very accurate when it comes to boost..any mods done ?? Link to comment Share on other sites More sharing options...
sheppd01 Posted April 13, 2012 Report Share Posted April 13, 2012 The psi gage shouldn't move until you step on it. I am not an expert but a 30 to 70 mph run in third gear will sound and feel a lot different from the same run in second gear. Admittedly when I have gotten on it I haven't paid much attention to the gage. All of my concentration is usually on trying to keep going strait. My guess is if you have the time to watch the gage it is because you are in to high of a gear or you are short shifting it. My car has about 660 hp but from what I remember the stock 540 can kick loose just as easy. Also I do believe the computer will not allow full hp if your car isn't warmed up or has limited amount of miles on it. Link to comment Share on other sites More sharing options...
JDB Posted April 13, 2012 Author Report Share Posted April 13, 2012 2,400 miles. No mods. Was at full temp. edit: so I think I got her figured out. My perception of having HP with (only) higher rpm's is off. This is probably engrained in me from driving non-supercharged cars. With the supercharger, she's got HP everywhere. Throttle hard in a higher gear at lower rpm's...that's when the supercharger lights up. Link to comment Share on other sites More sharing options...
rocky Posted April 13, 2012 Report Share Posted April 13, 2012 No, the blower does not kick in at low rpm's when you reach between 4000 and 6000 rpm's the blower (super charger) will start to do its job Link to comment Share on other sites More sharing options...
JDB Posted April 13, 2012 Author Report Share Posted April 13, 2012 So what's the supercharger whining about at hard throttle at tall gear/low rpm's? And that's also the only time my boost gage moves off of zero Link to comment Share on other sites More sharing options...
sheppd01 Posted April 14, 2012 Report Share Posted April 14, 2012 The only thing that I can think of is the SC whining seems louder when you punch it in a tall gear with low RPM because that loud KR exhaust isn't drownding it out. At high RPM (where the real HP is) the KR exhaust is deafening which makes the SC hard to hear. Personally I don't care too much about the SC whine. I love the sound of the exhaust and being thrown back into the seat. You are correct that that it has HP everywhere but the real stuff is at the higher RPMs. Link to comment Share on other sites More sharing options...
JDB Posted April 14, 2012 Author Report Share Posted April 14, 2012 Not disagreeing with any of that. My question really has to do with boost, why there's even a boost gage, and more importantly how to use the gage to understand why we're looking at it (I sure hope everyone who adds those gage clusters aren't doing it for the sake of simpy adding something to look cool). My reference point is Tom's(?) video from Sears Point. It sounds to me like he is starting the acceleration 1 gear higher throughout that what he could be, thus using a broader range of rpm's (and less shifting). Sure he brings it up to 5 or 6 at the shift, but it's the initial acceleration r's coupled with SC whine and probably boost readings that I'm curious about. The majority of the acceration is probably with boost, initially built by starting with lower rpm's. Yes, the SC adds HP at all rpms. Yes, peak HP is at higher rpm's. But here's my guess: the biggest gain of HP via the SC is when the boost gage moves (which if the car was not SC'd you'd see the biggest difference in lag). Build the boost, and maintain til the r's hit peak. If that wasn't important, why have the gage? Another way of thinking of it is: the engine has a crap-ton of HP and usually doesn't need the SC. But if the boost gage is moving, the engine has generated max HP at that instant, and the SC is then adding to that with a measurable gain. Unfortunately I can't simulate this on the street because I can only do the full range of r's within 1 gear until I hit 70mph on the on-ramp. On city streets, even up to a quick 50mph, it's tough to build the boost. A real quick spike is all I can muster at best, but for all practical purposes, the boost gage never moves. I am curious if people agree/disagree, or if I am the only one who's really driving their KR like they stole it. :D Link to comment Share on other sites More sharing options...
terumi71 Posted April 14, 2012 Report Share Posted April 14, 2012 Hi JDB, Reading your posts, I thought I would jump in and try to clarify some things. There are two styles of s/c. Root style and centrifical style. The stock Eaton is a root style s/c. It is a positive displacement s/c. It is always compressing air. The root style s/c will develop boost through the full range of rpm. You should see boost as soon as you get on it at around 8. There is really no curve with a root style. Centrifigal? Yes, you will develop boost only at higher rpms, then an increase in boost as rpm increases and a linear increase at that. But the root style is basically a squard curve. There is no curve. The boost you should be seeing is 8. And you should be seeing 8 when you get on it, even at lower rpm. It might increase very slightly as rpm increases, and might actually very slightly drop off just before redline. There are some possibilities with this 3-4 pounds of boost that you are seeing. The belt slipping is one of them. I think you could visualize how that would severely lower the boost. The other possibilities would be your driving. These cars are a monster to drive and keep the nose straight. Most especially with the traction control off. It will torque you left, into oncoming traffic in a second. With traction control on, even without the wheels braking loose, the computer is robbing you of hp as it is constantly modulating as conditions change in traction, again, even without the wheels being broke loose. You will only get the full compliment of hp with the traction control off. But beware if you do.....it's a wild ride! The traction control really makes us all much better drivers than we are!! Anyway...that's a little off the subject and not germain to the 3-4 pounds of boost that you are seeing. The traction control as far as I know, won't modulate boost. The s/c on these cars are as reliable as a brick. They do their job and don't often, "break". It's a simple unit doing a simple job...compresing air. As so, I would recommend someone sitting in the backseat, videoing exactly what is going on both with the gauge and your foot. Your foot must be to the floor. And you are hanging on...keeping the nose straight. The gauge is hard to read. Let someone else document what is going on while you do the driving. Advance through gears with your foot floored....making sure to be hooked up before flooring it. Again, the traction control will really help you in this area. But as you get into third gear and hooked up at 3-4k rpm, you should be able to get a steady reading of boost before shifting to 4th. And finally, if your really concerned, there is always the dyno. Numbers anywhere around 500rwhp, everything stock, should put your mind to rest that your car is functioning properly. Things to look for on a dyno: make sure, without insulting the dyno people, that the car is cross strapped in the back. Make sure the tires are either on the front of the dyno rollers, or the back on the dyno rollers. Not on the top of the dyno rollers. The hookup will be much better and your graph lines will be a lot straighter. There is a lot of technique for the guy doing the actual dyno. And that's tough to address without appearing that you are getting up in their grill. So I don't think I would say this next part to them. But as the car gets up to redline in fourth gear where they are going to do the reading, they have their foot near the clutch, ready to hit the button and mark the rwhp, then immediately afterwards hit the clutch. Unfortunately, the dyno guys can get a little antsy as they are approaching redline, and they start lightly riding the clutch; believing that they are touching the clutch without depressing it ever so slightly. Riding the clutch in any amount will rob the car of hp on that final reading. So if you see squiggly lines at the very top of the hp graph, it's more than likely he was slightly riding the clutch. In that case, just continue the nice clean line upwards on the same slope, and extrapolate your own final hp reading as if the dyno was done perfect. If you are seeing anywhere close both +/- of 500rwhp, your car is fine. You should be getting 8 pounds boost through the range of rpm. Foot to the floor for that reading to be accurate. Have someone in the backseat with a video to document. You drive and don't try to read the the boost gauge. Barring the belt slipping, I would say it's your driving. And that's not meant to offend. These cars are very light in the rear with a goofy weight bias. It's understandable to be cautious. The blowers are very reliable so I doubt it's something mechanical with it. And there's always the dyno to put your mind completely to rest. Hope it helps! Steve Link to comment Share on other sites More sharing options...
JDB Posted April 14, 2012 Author Report Share Posted April 14, 2012 Thanks for that detailed info Steve. I appreciate it! I just turned the t/c off and hammered REALLY hard up a couple on-ramps. Foot to the floor, good shifts. Definitely blew plast 70mph in a heartbeat and felt the wheels break in several gears. No problems keeping her pointed in the right direction though, and was definitely a rush like I've never experienced. Saw the boost spike around the 10 mark, so that would be the 8 that you speak of. I am still a little concerned though in the other scenarios. Being a Roots and always compressing, mine is still stuck as zero even with (what I'll now call moderate) accelleration. Can you confirm that's somewhat normal, or does that seam a little out of place to you? I'm sure it's just my driving and just getting used to it, but I like to know every detail before I come to a conclusion. Besides belt slipping, are there any release valves on these that could be partially open/leaking? And FWIW: the gage really is useless if the only time it moves is when you're too busy to look at it. Link to comment Share on other sites More sharing options...
terumi71 Posted April 14, 2012 Report Share Posted April 14, 2012 Sounds like everything is working fine. Moderate acceleration to me meaning just going hohumm through the gears, no, the boost needle won't move. It's still compressing air. But you're not going to see the needle move. It's not until you get on it....then really get on it....that you'll see the needle move and go to 8 or so with full throttle. I think everything is working just fine from what it sounds like! Steve Link to comment Share on other sites More sharing options...
JDB Posted April 14, 2012 Author Report Share Posted April 14, 2012 Sweet. Thanks for the help! Link to comment Share on other sites More sharing options...
shelbypt Posted April 16, 2012 Report Share Posted April 16, 2012 I agree, there is no boost on the gauge at low load driving. The gauge will read zero. With about 1/2 to full throttle, the gauge will shoot up to 9-10psi. If you can take the KR up to full throttle all the way through 3rd, 4th, and even 5th gear you will hear the superchager for sure. Now, this sc has a vacuum operated bypass valve on the back of the sc, on the drivers side. At low loads, I believe this valve to be open, therefore no boost into the intake. At higher loads the valve closes allowing boost into the intake, thus the gauge displays the boost. Link to comment Share on other sites More sharing options...
FiaCobra Posted April 16, 2012 Report Share Posted April 16, 2012 I don't think you're driving it hard enough ! Turn off traction control and hammer it ! Just keep it straight while mashing through the gears. Link to comment Share on other sites More sharing options...
terumi71 Posted April 16, 2012 Report Share Posted April 16, 2012 lol Fia! Concerning the vacuum. From what I understand, that valve is there to prevent pulsing and/or surges. It's default position is allowing air to the sc.. And the sc by default is always moving air, even at a low load. It's job is not to bypass the s/c at low loads. Rather, it is to prevent surges / pulsing. At least that's the way I always understood it. Drive it JDB!! Have fun with it!! Link to comment Share on other sites More sharing options...
revan Posted March 7, 2014 Report Share Posted March 7, 2014 Sorry to reawaken an old post, but there is one additional item I'd like to add in case others read this thread. As far as I've been told, by multiple sources, the boost gauge that comes in the center display as actually inferred boost - meaning it's being calculated by the computer based on readings of the tach and assumptions built into the tune. If any mods are done then it's more than possible this calculation will be "off".If however you have a gauge pod setup with a true boost gauge wired into the vacuum lines then that will always read "true" boost. Anyone, feel free to correct me if I'm wrong on any of this. Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted March 7, 2014 Report Share Posted March 7, 2014 Sorry to reawaken an old post, but there is one additional item I'd like to add in case others read this thread. As far as I've been told, by multiple sources, the boost gauge that comes in the center display as actually inferred boost - meaning it's being calculated by the computer based on readings of the tach and assumptions built into the tune. If any mods are done then it's more than possible this calculation will be "off". If however you have a gauge pod setup with a true boost gauge wired into the vacuum lines then that will always read "true" boost. Anyone, feel free to correct me if I'm wrong on any of this. I've heard this too, Van...But I don't buy into it. I could easily be wrong but..... It's too easy to get a direct reading for boost by using the sensor already in place. That and, the PCM *has* to know actual boost (Manifold) pressure to give a accurate AFR/Injector/output signal, not "just" a MAF signal. MAF is the primary input signal, not the *only* input signal. I added a Ford Racing (Electronic) Vac/Boost gauge to my 2010 GT500 and still have the OE gauge in the dash. I'll try to remember to check and see if they correlate with each other next time I'm out for a buzz. I'll try to remember to post my results here. Phill Link to comment Share on other sites More sharing options...
JDB Posted March 7, 2014 Author Report Share Posted March 7, 2014 I'll try to remember to check and see if they correlate with each other next time I'm out for a buzz. Wow good luck with that. Anytime I put my foot into it enough to get the gauge to move, I'm scared sh*tless to look down. Link to comment Share on other sites More sharing options...
Doug_GT350 Posted March 7, 2014 Report Share Posted March 7, 2014 Wow good luck with that. Anytime I put my foot into it enough to get the gauge to move, I'm scared sh*tless to look down. Now you're driving it right! Link to comment Share on other sites More sharing options...
revan Posted March 7, 2014 Report Share Posted March 7, 2014 Now you're driving it right! AMEN! I've heard this too, Van...But I don't buy into it. I could easily be wrong but..... It's too easy to get a direct reading for boost by using the sensor already in place. That and, the PCM *has* to know actual boost (Manifold) pressure to give a accurate AFR/Injector/output signal, not "just" a MAF signal. MAF is the primary input signal, not the *only* input signal. I added a Ford Racing (Electronic) Vac/Boost gauge to my 2010 GT500 and still have the OE gauge in the dash. I'll try to remember to check and see if they correlate with each other next time I'm out for a buzz. I'll try to remember to post my results here. Phill Just want to make sure every know that I'm not THE Van from Revanracing.com. I WISH i had that level of knowledge Sorry for any confusion, I created this account before I met Van and it's confused people here and on other forums ever since :/ Hey @Jer is there any way you can change my username for me? Phill, what you're saying makes perfect sense so maybe I'm wrong. In theory though I think they can take the MAF signal and based on the air flow predict what manifold pressure would be, given temperature, barometric pressure, and whatnot. Not sure, but either way I have Aeroforce gauges with a boost sensor waiting to be installed when I stop being lazy and work up the nerve to try the install (I HATE electrical stuff!) lol. As for the behavior the OP mentioned, I can second that it behaved like that for me for all configurations I've had: - Stock 500HP it came with (I don't have a KR) - The estimated 540HP config when I added the KR intake/tune package - Even now it does this and I'm running low 700's at the crank with a VMP TVS setup and a 2.8" pulley. Being a roots blower it is always creating boost, but I'm thinking ford simply programmed the gauge to only show a reading when at WOT, or at least above a certain threshold. P.S. Another tidbit of info - when it was bone stock, the boost would completely drop off around 4800 RPMS (and the supercharger whine disappeared as well). Adding the KR intake and tune resolved that. According to what I read, the drop off was due to air starvation since the stock box couldn't flow enough air at that RPM. Not a problem for the KR intake of course. Link to comment Share on other sites More sharing options...
2010KonaBlueGT Posted March 7, 2014 Report Share Posted March 7, 2014 Phill, what you're saying makes perfect sense so maybe I'm wrong. In theory though I think they can take the MAF signal and based on the air flow predict what manifold pressure would be, given temperature, barometric pressure, and whatnot. Not sure, but either way I have Aeroforce gauges with a boost sensor waiting to be installed when I stop being lazy and work up the nerve to try the install (I HATE electrical stuff!) lol. Actually, I don't think you're "wrong" at all. Yeah, it's totally possible AND feasable to use multiple sensor inputs to "calculate" the manifold pressure (vacuum OR boost) but my point was....WHY!? Why, when they can just take the man. pressure off of *one* sensor (I can't remember what it's called but it's not a MAP). What I *think* is going on is a slight misconception. It is true that the PSI gauge is based on what the PCM *thinks* is happening. That is (for instance) when you use a scan tool to see input sensor parameters, you may or may not be seeing reality. What you're seeing is what the PCM THINKS is happening. That's because the input sensor goes to the PCM, then the PCM calculates what the voltage signal means and sends the output (boost gauge in this instance) a signal of what the Manifold pressure is. That is also why you *always* test a input/sensor by pinning in AT THE SENSOR and not rely on the OBD port (via the PCM) for readings. A little bit of resistance in the circuit can fool the PCM into thinking the engine is doing something different than reality (I did this shit for a living). Phill Link to comment Share on other sites More sharing options...
revan Posted March 7, 2014 Report Share Posted March 7, 2014 Yep, I agree, WHY would you do it that way....then I remember just how much Ford skimped on our cars to save cost. Willing to bet they might have done it there too (kinda like how the 07-09 motor has no knock sensor).Either way, I'm like you and would rather read that measurement directly than trust the PCM to report it. Hence why I'm about to wire boost and wideband sensors to my gauges so I can do just that. Link to comment Share on other sites More sharing options...
twobjshelbys Posted March 8, 2014 Report Share Posted March 8, 2014 Sorry to reawaken an old post, but there is one additional item I'd like to add in case others read this thread. As far as I've been told, by multiple sources, the boost gauge that comes in the center display as actually inferred boost - meaning it's being calculated by the computer based on readings of the tach and assumptions built into the tune. If any mods are done then it's more than possible this calculation will be "off". If however you have a gauge pod setup with a true boost gauge wired into the vacuum lines then that will always read "true" boost. Anyone, feel free to correct me if I'm wrong on any of this. I believe so. It is also true of the Ford GT. I had a S/C pulley and tune and my boost gauge is now "offset". For the GT there is a gauge kit that will convert it to an actual vacuum/boost port on the supercharger. That's good because the gauges on the GT are the weak link Link to comment Share on other sites More sharing options...
revan Posted March 9, 2014 Report Share Posted March 9, 2014 haha, yeh I imagine the weakest thing on a GT is the gauges I imagine there's a way to wire in a true boost sensor to the boost gauge on my 500, but I'm too lazy to take apart the dashboard plus I HATE electrical stuff. Easier to just tap the line to install the boost gauge I have and then wire it to one of my aeroforce interceptor gauges. Either way I'm more concerned about monitoring my A/F since that's what can really damage this motor. In fact I'm so OCD I plan to wire a wideband sensor into BOTH manifolds so I can track A/F on both banks, lol Link to comment Share on other sites More sharing options...
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