When surge occurs in these conditions, it can be particularly severe. I assumed it was compressor surge and assumed it wasn't good so was just wondering if any else has had a similar problem and how I could go about fixing it. i plugged my old BOV and installed Tials BOV … There may be a vacuum leak. When you are at wide open throttle and you hear surge, thats different, and there's nothing the surge valve can do that can stop that because it's not from the surge valve closing too early. The fix: Remove the tank and siphon the bad gas out by using a garden hose. The most obvious is to increase flow (see section on Antisurge Valves below). hey everyone. In the words of compressor expert Ivor Day, stall is a disturbance of compressor flow in the tangential direction, while surge is a disturbance in the axial direction. when we speak of compressor surge there are two that come to mind #1. when you come off the throttle without a BOV the pressure must go somewhere. On more modern cars you have a throttle body that adjusts the idle speed instead of the idle control valve. What Causes Compressor Surge? With the throttle 100% open (foot to the floor) in 2nd, 3rd or 4th gear, and at 2500-3000 rpm's, I … Possible internal engine problems. When a centrifugal compressor surges, there is an actual reversal of gas flow through the compressor impeller. Flutter sound with throttle OPEN - video included. So by his theory at maf-less car (SD) set up would not have a part throttle surge. Once the 9700 RPM has been reached, the throttle is completely closed and here the interesting and relevant part begins with the subject of the present discussion: while the power valve is open, the efficient exhaust scavenging keeps the combustion chamber sufficiently clean, but under a certain RPM the exhaust valve closes and the deceleration surges (in the chart there are 3, … So when I open the throttle up I get the same noise as above with reduced power. The open-loop backup is triggered by a large predicted overshoot of the surge setpoint to prevent surge, or a precipitous drop in flow indicating an actual surge. Then refill the dry clean tank. This is not a DIY job. An innovation uses a predicted overshoot via a fast future value that is generated by the rate of change of a decreasing flow, with a good signal-to-noise ratio multiplied by the total loop dead time, with … But today I heard something different. Bad throttle position sensor symptoms. When your throttle is suddenly closed, the turbocharger lags behind in response time. So I installed a Green filter a couple of weeks ago (the only mod on the car), been loving the noise of the turbo. To the OP. EGR valve may be stuck open. So the turbo is running full boost but the flow is being restricted. The A/S system moderates a bypass valve that spills back to the suction line enough gas to keep the discharging gas from flowing backwards internally in the compressor (surge). its causing alot of stress on your turbo's shaft and bearings. A C20 on start-up has the bleed valve open to allow acceleration of the compressor without getting too much air into the combustor. Symptoms Of Bad Gas In Car; How Long Does It Take For Gas To Go Bad? if you get it when your boosting less than 4 psi you should be ok and is normal for alot of people i know. EGR valve stuck open. One issue i cant seem to fix is if i am cruising at circa 3000rpm-3500rpm in top gear, when i got full throttle as the turbo spools, it starts to surge, which is obviously not a good thing, so at the moment to control this i have to blend off the throttle through the zone it surges when full throttle, then i can go WOT again post the surge point. The impact of compressor surge can be minimal at low boost levels as shaft speeds are low. For anyone that has compressor surge while shifting when you were in vac. Inlet throttle or modulation control: The inlet butterfly forces the compressor to operate on its characteristic curve when the demand is less than rated capacity. compressor surge at low psi wont be as harmful as having comprssor surge at full boost. The problem may involve an annoying change ... • A/C compressor cycling on/off due to low refrigerant • Faulty TPS ... causing the pedal to be slightly depressed (causing the throttle valve position to be slightly open). Surges can occur when mating a large compressor or a “high flow” compressor wheel to a small turbine to enhance low RPM response. You can fix it by attaching to a true vacuum source but it isn’t needed. Compressor surge? I have messed with the tune a bit, changed to new I/C plumbing etc.. thinking it was a setup problem. The surge usually starts in one stage of a multistage compressor and can occur very rapidly. Compressor surge is a whole nother beast . As the inlet valve closes and the rising pressure approaches surge point, the bypass valve matches demand by opening slowly to bleed off excess air. Faulty Throttle Body or Throttle Body Sensor. Replacing the belt often eliminates the surge, and ensures better AC operation. The fix: Check lock up circuit or have the torque converter replaced. You end up going to the left of the surge line on the compressor map. Flutter sound with throttle OPEN - video included. It stays open, closing gradually, until around 92% N1 when the engine can take all the air OK. A compressor can be brought out of surge in a number of ways. If the centrifugal compressor experiences surge during compressor operation, it is considered to I have tried everything I can think of to eliminate this situation. Since turbos in that era were slow to spool up, maintaining shaft speed was a high priority. One of the first bad throttle position sensor symptoms is the Check Engine Light will flash on your … During stalled operation, the average air flow through the compressor is steady, but during surge, the flow rate will rapidly (milliseconds, msec) pulse—sometimes so violently that reverse flow is induced, often … A suitable blow-off valve will open quickly enough, and have the flow capacity to avoid compressor surge, while equally being able to close and seal rapidly when the throttle is open again to build boost and aid throttle response and acceleration. Compressor maps graph a turbocharger's performance, relating its relative atmospheric pressure value to the airflow rate through the turbine. This places significant strain on the engine and the AC system. all this has happened in the last two days and i cant seem to fix it. Decreasing discharge pressure and/or increasing speed are other ways to move out of a surge condition. Being that the 49 series turbos are especially prone to this, it'd be interesting if anyone had this surge, changed to an SD set up and if the surge was gone. That surge is simply from the turbo pushing too much volume or air (not pressure) into the engine and the engine is spitting it back out through the turbocharger's compressor inlet. I suspect this really has something to do with it. Surge Mechanism. READ MORE. The fix: Replace EGR valve. having it at full boost or 6 psi+ imo is not good. Compressor surge, or turbo flutter, doesn’t occur on the turbine side of the turbocharger, but rather on the compressor side. This puts the turbo in the surge region of the compressor … When you let off the throttle it opens in order to release pressure from the intake track because your turbo is still boosting. If the belt is stretched or worn smooth, it can slip during operation. so it collides midflight and causes a massive pressure spike on the compressor side of the turbocharger. That will kill a turbo real fast . The Exhaust Gas Recirculation (EGR) valve is an important part of your car’s emissions system. As we all know HKS designs all of there BOV's for high boost applications, and for us with little early spooling turbos the SSQ can cause a moderate amount of compressor surge. Check Engine Warning Light. Address throttle position sensor problems as soon as possible to avoid risks of accidents and damaging your delicate engine.. Fig. i checked for leaks. for myself, i … • The accelerator pedal may not be fully released. - In this way, a co. To let out the back pressure and allow the wheels to spin up faster. The fix: Check compression to determine engine condition. I have always had a compressor surge (or at least it sure sounds like it) in 3rd past about 1/2 throttle in the upper RPMs. Without suction throttling, the compressor control in the low capacity range (close to the surge line)would be provided by the anti-surge system. But compressor surge can occur under wide open throttle operation and we're going to find out why that's the case but essentially one of the keys there is it really comes down to turbocharger sizing. The wastegate is set for ~ 20+ psi, and the turbo is creating 20 psi in the intercooler, but the driver has backed out of the throttle to limit manifold pressure. Then, an offset from the value is entered. The turbine has exhaust gas that it’s trying to use but can’t. I guess there isnt a propper name for this so compressor surge isnt technically the wrong name . the massive spike in pressure causes the compressor wheel to surge in speed It is a common problem that the throttle valve gets dirty and causes rough idling. The use of IGV’s can effectively throttle the compressor with the added benefit of being ... modulate open. yes thats compressor surge. Thats a miss match of turbo wheels and you have air stalling and forcing itself backwards out the comp wheel while you are still on full boost/throttle . not sure yet. Jump to Latest Follow ... generally you cant hear wastegates open especially when the exhaust is plumbed back into the exhaust versus being dumpped. How much boost do you get ~2800rpm? you should def fix it asap. im having inssues with my vacuum or turbo. Care should be taken when selecting a turbo so that it will not operate in the surge region at full throttle or at any RPM. i just cant seem to fix it. A skilled technician “surge tests” the air compressor, and enters the surge control limits in “feet”. Jump to Latest Follow ... Having fuel rail pressure issues and honestly feel like it's fully popping open at times during high throttle, ... That’s the sound you’re hearing and it’s normal. The surge starts with the instant flow reverses, shown in the above figure. go on youtube and search tails bov surge or my channel [wayne peconi]. If the polytropic head reaches the offset value, the air compressor controller starts to open the blow-off valve to avoid surge. All so I don't think it is the BOV, I run the stocker on a 20G and it won't surge at part throttle. Below are the most common symptoms of a bad throttle position sensor. On the other hand, if you hear turbo flutter when you’re on the power - known as open-throttle compressor surge - then brace for big bills. During the early ‘90s, it became common practice for car manufacturers to fit DVs to their turbocharged models to prevent compressor surge. The fix: Check and replace vacuum lines as required. i have a couple up there. The left side of the compressor map is known as the surge line, which defines the minimum ratio of pressure value and flow rate required to avoid compressor surge. Compressor manufacturers usually perform an aerodynamic performance test before delivering the compressor. Interesting video. The other option or area where we can run into compressor surge is where we are backing off the throttle which I've just mentioned there with my little rally car analogy. toughen my BOV spring and weakend it. It opens again on sudden accelerations. Surge can happen at full throttle when you try to run too much boost at low rpm. Compressor surge? A wide variety of issues can prompt an engine surge. Bad Belt: One often overlooked cause of a car surging with the AC on is actually a worn compressor belt. Well today I was board, and still pondering the compressor surge issue. 3. By eliminating compressor surge, the turbo would not slow as rapidly when the throttle was lifted. But this doesn't happen all the time and sometimes it goes away the higher the revs. Now we will see how the surge starts in a compressor.