TRANSMISSIONS

DOES GOEREND TRANSMISSION STILL BUILD FULL TRANSMISSIONS IN-HOUSE? 

We no longer build full transmissions in-house but do supply many customers with quality components to make a build as robust as possible. Customers have the option to rebuild their transmission themselves, at a trusted shop, or at a Goerend installer. Before purchasing one of our used transmissions, contact us to verify its authenticity. To transfer the warranty, the original owner must contact us with the invoice number and new owner's contact information in order to set up an applicable warranty transfer.

WHAT 47/48RE TRANSMISSION FLUID SHOULD I USE AND SHOULD I USE AN ADDITIVE?

47/48RE transmissions first used Dexron fluid, then Chrysler 7176 fluid, then Mopar type 3, and now Mopar type 4. We have used all without any problems. There are many good fluids you can use, most synthetics are fine. You can use Dexron 3 or Dexron/Mercon alone or with a Lubegard additive. We DO NOT use Dexron 6 or any other additive other than Lubegard. Do not use a type A / Suffix A fluid. This is for 1966 and older transmissions. Type F will give a firmer shift but we do not recommend it, or Type CJ. We use Dexron 3 and a bottle of Lubeguard. Other types of transmission fluid include Amsoil Synthetic and Mopar type 4. Do not use Lubeguard additive with these fluids.

Fluid Capacity for Rebuilt Transmissions:
OE Pan: Holds approximately 14 qts.

1. Pour in 6 qts.
2. Start truck.
3. Add 7-8 more qts.  
4. Start checking fluid level. The transmission needs to be in neutral. Take the reading from low side of the stick. Add fluid until full.
5. Re-check fluid level after driving 5-10 miles

Goerend Pan: Holds approximately 16 qts.
1. Pour in 8 qts.
2. Start truck.
3. Add 6-8 more qts.  
4. Start checking fluid level. The transmission needs to be in neutral. Take the reading from low side of the stick. Add fluid until full.
5. Recheck fluid level after driving 5-10 miles.

Double Deep Pan: Holds approximately 19 qts.  
1. Pour in 8 qts.
2. Start truck
3. Add 9-11 more qts.  
4. Start checking fluid level. The transmission needs to be in neutral. Take the reading from low side of the stick. Add fluid until full.
5. Re-check fluid level after driving 5-10 miles

NORMAL 47/48RE TRANSMISSION TEMPERATURES & SENDER LOCATIONS

There are 3 basic places to install a temp sender for the transmission; the transmission pan, front cooler line, or one of the transmission case pressure tap ports. There are pros and cons to each location. Many people like to install the sender at the front cooler line. This location will give you the temperature of the fluid coming out of the converter and will be the highest temperature you will see from the transmission while in the fluid coupling mode. On the 1994-1995 transmission, there is a temp sender already in the front line that gives information to the transmission computer so it will not let the transmission go to 4th or lock the converter clutch until the transmission and engine are warmed up. At approximately 70° it will take approximately ½ mile of driving before the computer will command a 3-4 or lockup shift. At approximately 30° it will take about 31/2 miles before it is warm enough for the 3-4 lockup and if the ambient temperature is negative, it can take more than five miles. If you have a 1994-1995, this sender must stay in the line. If you are going to install a gauge sender in this line you must make a manifold to install the second sender. The original sender must be in contact with the fluid, taped to the line is not good enough. One problem with a manifold set up for the sender is that it adds weight. That, coupled with vibration could crack the line and cause a leak that you would only see when the engine is running. 90% of the heat in a properly operating automatic transmission comes from the torque converter fluid coupling. The fluid coupling is when the drive fan of the converter is blowing oil at the driven fan. Once the converter clutch locks the fans together, the power is transferred to the input shaft. Because the fluid is not being used to transfer the power while in lockup, no heat is transferred to the fluid. The more efficient the fluid coupling is, the cooler it will run while moving. An efficient converter will run hotter when you are in gear but not moving. This is because when not moving, the impeller is still moving with the engine and trying to transfer the power to the turbine. If the turbine is stationary, as would be while at a stop sign, the power has no place to go but into the fluid and out to the cooler as heat. On the other hand, when you are up to speed and the converter clutch locks the both fans together, you are now transferring 100% of the power to the rear wheels and the power will be transferred to the rear wheels. When the lockup occurs you would see an immediate drop in fluid temperature of about 20°. Normal temperature of the transmission fluid will fall in the area of about 100-280° depending on where you check it.

Pros for the cooler line location are that you will see the full range of temperature. Normal temperatures when monitored at the front cooler line would fall in the range of about 140-280°. While watching the temperature at the front cooler line, you can instantly see the temperature climb if you are pulling a heavy load. You can also see the temperature fall almost instantly when you back off the throttle and you can also tell that the converter clutch was commanded to lock because the temperature will drop instantly even when under heavy load. Cons of the cooler line location, and one of the reasons I prefer the sender in the pan, is because if you are monitoring the gauge this closely, your eyes will not be on the road. This is a very active gauge when the sender is in the front cooler line. The sudden and extreme range of temperature you will see can make one nervous even though they are well within the norm at this location. Just the opposite is true if you install the gauge in one of the pressure ports of the transmission case. The fluid at any of these test ports is stagnant oil, once the oil gets to the test port, it is at a dead end and is no longer circulating. At one of these locations, we will actually be reading the temperature of the transmission case. These locations take the longest to get a reading, and by the time you see a reading above 200° the converter temperature was probably around 250-270° for quite some time because it takes a while for the heat to radiate into the case and once the fluid cools it will also take a while for the case temperature to drop. At this location expect to see normal temperature range from about 140-190°. Pull over if the temperature reaches above 200°.

Pros for the pressure test port location would be ease of install and multiple locations to use. Cons for these locations would be slow gauge reaction time. We also need to make sure the sensing tip of the sensor is not too long and bottoms out before you have the sensor tight. We do not recommend these locations.

We like to install the temp sender in the transmission pan. The gauge will react quick enough to save the transmission form over-heating and yet the gauge won’t be so active that it would make one nervous about temperature extremes. The normal temperature range you would see will be about 140-200°. If the transmission temperature gets above 200° we would want to get the engine RPM above 1,500. Fluid that is cold does not move very quickly through small passages, like the small passages in the valve body. Fluid that is too hot is hard to pump because it is too thin. Fluid at 230° does not hurt the seals, gaskets, or clutches, but because it is so thin it is hard for the pump to maintain enough flow so the valve body can maintain enough pressure in all the circuits. At approximately 200° in the transmission pan, even a good pump will have a hard time flowing enough fluid to satisfy all the circuits when the pump RPM is below about 1,300. If the pump can’t maintain the volume of oil and the pressure regulator valve cannot maintain good pressure, the clutches and bands will slip. The cooler flow and pressure will also be lower and this will escalate the heating problem. This can easily be seen on the transmission dyno where we can monitor transmission temperature, clutch pressures, cooler pressures and volumes. Even with hot fluid above 200° these pressures and volumes come back to normal when we bring the RPM close to 1,500. With 4.10 gears this is not a problem because the engine RPM will not be around 1,500, but with 3.54 gears you can easily be at 60 MPH or lower with the converter locked up and the engine RPM could be around 1,500 depending on tire diameter, of course.

For the above reasons, we do not like to get the converter stall too low. If someone wants an extremely low stall converter and they are going to do a lot of snow plowing, the engine and customer may like the low RPM but if you are working things especially with the converter clutch unlocked at low RPM, the pressure and cooler flow may suffer.

HOW DO I ADJUST THE FRONT BAND?

If a vehicle is equipped with a Goerend valve body, loosen the lock nut and tighten the adjustment bolt to 72 inch pounds and finally loosen 2¼ turns.

HOW DO I ADJUST THE REAR BAND?

Tighten the adjuster to 72 inch pounds and loosen 3¼ full turns.

DODGE 1740 CODE

On a late model truck, usually 2004-2007, any stall speed different than the factory stall (17SS) can set a 1740 code. This code will turn on the check engine light but will not affect the operation of the transmission or engine. This code sets because the computer constantly monitors the engine RPM and compares it to throttle angle and road speed. With a lower stall converter, the computer sees the lower engine RPM and believes the lockup or overdrive solenoid is mechanically stuck on. The computer can check for electrical faults and will not detect any, and believes the lower RPM is due to the converter being locked up or the transmission is in overdrive, even though it is not. Most programmers can erase the code. This code will not affect the transmission or engine operation.

PANS

WHAT IS THE DIFFERENCE BETWEEN A GOEREND TRANSMISSION PAN AND OTHERS?

We designed our own pan to get several features that we could not find in other pans. Our pans have a sloped floor on the inside of the pan so all the fluid will drain out. Our drain plug takes a 1" socket: no more stripped Allen heads or threads. Our drain plug is magnetized and is at the lowest point in to catch any magnetic debris. Other drain plugs sit above the bottom of the pan and will not catch debris. The exterior of our pan is flat so the transmission can sit on a jack without rocking. The sides of our pan are not ribbed to increase strength. Our pans are designed to be more fragile than the transmission case. Other pans that are excessively beefed up on the side may be too strong tougher to break, which will result in the breaking of the transmission case instead. It is much easier and cheaper to replace the transmission pan than the transmission case.

WHAT TRANSMISSION FILTER SHOULD I USE FOR A 47/48RE?

There are two different transmission pans that were used from the factory on these transmissions. The pan that is completely flat on the bottom is the deeper pan and should take the plastic filter because it sits deeper in the fluid. If you have a deep aluminum pan that uses a filter lowering block, we would recommend using the open element filter that has the paper filtering element on both sides because it fits the lowering block better. For best results, use either Mopar or Transtar transmission filters. We also prefer to use the old style filter because it seals up better.

FLEXPLATES

FLEXPLATE INSERT INSTALLATION INSTRUCTIONS 

VALVE BODIES

WHAT MAKES A GOEREND VALVE BODY DIFFERENT THAN THE COMPETITORS OR DIFFERENT THAN INSTALLING A VALVE BODY KIT?

We like to keep shifts smooth as possible. Not a slippery long drawn out shift, but a quick and smooth shift. When you step into the throttle and the engine power increases, the pressure in the transmission also needs to increase. Our valve bodies have a much faster and steeper pressure rise than other valve bodies. A factory valve body normally has idle pressure of 60 PSI and wide open throttle pressure is near 100 PSI. Goerend valve bodies will start at 70-90 idle PSI, depending on truck, and the pressure rise to 150-190 PSI at wide open throttle.

WHEN ACCELERATING AT ¾ THROTTLE AT 40 MPH, MY TRANSMISSION SEEMS TO SHIFT TO NEUTRAL & THE ENGINE REVS TO REDLINE.

Some trucks have a problem while accelerating at about ¾ throttle around 40 MPH. The transmission will neutralize and the engine will rev up, just like it shifted to neutral instead of 3rd gear. If the throttle is then let off, it bangs into 3rd gear. A Goerend valve body will correct this. Many trucks have gear hunting from 2nd to 3rd. As long as the governor solenoid is in good condition, a Goerend valve body corrects this. Most people who build valve bodies do not know that the torque converter circuit is regulated to 130 PSI from factory. It is common practice to eliminate this circuit and give the converter full line pressure. This is not good and is the main cause of ballooned converters. A Goerend valve body has the proper regulation in the converter circuit.

WHAT IS THE DIFFERENCE BETWEEN A TOWING, SLED PULLING OR DRAG RACING VALVE BODY?

On a towing valve body we want a smooth shift. This helps keep shafts and planetary gears from breaking due to the high shock of brutal shifts. We also build the valve body so you can downshift from 4th to 3rd and from 3rd to 2nd with the converter locked in case you have an exhaust brake. If a toggle switch is installed you can also lock the converter while in manual 2nd so the converter will not overheat while towing a heavy load up a steep grade.  

On a sled pulling valve body you most likely will want the converter clutch to be capable of locking in 1st, 2nd, 3rd and overdrive and also be able to back shift from overdrive to 3rd, 2nd, 1st with the converter locked.

On a drag racing valve body we normally lock the converter right after the 1-2 shift. We can build the valve body so it will not lock the converter in 1st. That way you can turn the lock-up switch on while at the starting line and it will not kill the engine and as soon as it shifts to 2nd the converter will automatically lock up.  

IS THERE ONE VALVE BODY THAT WILL WORK WELL FOR DAILY DRIVING, TOWING, DRAG RACING AND SLED PULLING?

Yes and no. Up to about 500 HP you can use the same valve body and it can work well for all. Once above that, there are things we need to modify on the valve body that would be specific to drag racing and sled pulling that would not be done to a daily driver or tow rig.

DO ALL VALVE BODIES NEED THE EXTRA SPRING FOR THE FRONT BAND APPLY SERVO? 

All Goerend valve bodies need the spring. We do make valve bodies that are not as high a pressure and do not require the extra spring. These valve bodies have all the same upgrades as the high pressure valve bodies - only with pressures that are slightly above stock. These valve bodies are for people who want to install a valve body only and do not have to remove the trans to install the billet 1-2 shift lever.

WHAT IS A CONSTANT PRESSURE VALVE BODY AND WHY WOULD ONE BE NEEDED? 

Normally the pressure that applies the clutches and bands in a transmission will be low at idle and high at wide open throttle. With a Goerend constant pressure valve body, the pressure is high at all times, both at idle and wide open throttle. A constant pressure valve body is normally used for trucks that are racing or with engines that have high power.

WHERE DOES THE BIG SPRING GO THAT COMES WITH THE NEW VALVE BODY? 

This spring goes into the front band apply servo along with the original spring. This is the servo that applies the front band.

CAN A VALVE BODY BE INSTALLED WITH A STOCK 2ND BAND APPLY LEVER?

We have seen the stock 2nd band apply lever break with stock valve body pressures, not often, but we have seen it happen. If a valve body is being installed with higher pressures we recommend you remove the transmission and install a lever made with a stronger material. We do make a stock pressure valve body with all the other features in our high pressure valve bodies.

WILL A NEW VALVE BODY CURE ALL MY SHIFTING PROBLEMS? 

Many shifting problems can be cured by a valve body, but the shift timing is controlled by the computer. On a 1995 and older, the 3-4 and converter lock up is computer controlled. On a 1996 and newer, all shifts are controlled by computer, so if you have a bad input to the computer, such as a bad throttle position sensor or output shaft speed sensor, they can affect the shifting and that would seem like a valve body problem even though it is not.

WHAT ARE THE PRESSURES ON OUR VALVE BODIES? 

A Goerend valve body can have pressures ranging from 70 PSI at idle to 190 PSI at wide open throttle (WOT). Driving habits and truck use will dictate what pressures are needed. We also have constant pressure valve bodies where the pressure is fixed, the pressure is the same at idle as it is at wide open throttle.

VALVE BODY APPLICATION/ORDER INFORMATION

Goerend High Pressure Valve Bodies are designed to run with a Triple Disc Torque Converter, a billet input shaft, a 3.8 ratio front band apply lever, and a Goerend heavy front servo spring. If there is any variation from the above mentioned features, modifications will need to be made to the valve body to accommodate. Click here for our valve body questionnaire.

YEAR TRANSMISSION LETTER CODE

1991-93

47RH Non-Lock

A-NL

1994-95

47RH

A

1996-98 12V

47RE

B

1998-99 24V

47RE

C

2000-02

47RE

F

2003

47/48RE

X

2004

48RE with cable

X

2005-07 5.9L

48RE with TTVA

W

TORQUE CONVERTERS

HOW DOES A TORQUE CONVERTER WORK?

Let’s start with two wall fans facing each other: If we turn one fan on the wind from this fan will make the other fan turn, although much slower than the "drive" fan. In the case of a torque converter, the drive fan is bolted to the engine and the fan being driven is connected to the input shaft of the transmission. In addition, oil is used to transmit the energy between the two fans, as opposed to air in the example scenario.

When stationary (such as at a stop sign), with the transmission in gear and the engine at idle, the drive fan is spinning so slow that it will not transfer enough oil to the driven fan to make it turn. As the engine speed is increased, the drive fan blows more oil at the driven fan and the driven fan starts to turn and moves the vehicle. This important concept is commonly referred to as fluid coupling.

The drive fan will always turn a little faster than the driven fan, just like the wall fans. If you were to stick a feather, or straw, into the driven fan blades it would slow the driven fan down but not the drive fan. In a real application this is just like pulling a heavier trailer, the straw in the driven fan is essentially adding a load.

LOCKUP

Once the truck is up to speed there is a mechanism, called a lock up clutch, that will lock the fans together. In actuality, the driven fan is locked to the front cover of the torque converter, which is bolted to the engine. When this occurs, the drive fan and driven fan turn at the same RPM, with no loss of power in the fluid coupling. When the drive and driven fan are not locked together, heat is generated in the converter. The greater the load and RPM difference, the greater the heat generated. This heat is essentially lost power which results in a lower transmission life, performance and fuel economy. The loss of energy in this process can be calculated. Suppose we have a converter where the drive fan (impeller) is turning 2500 RPM and the driven fan (turbine) is turning 1800 RPM. The efficiency of this converter, at this speed, is 72% (1800 divided by 2500). The efficiency is constantly varying, depending on the RPM of the converter, the power input to the converter and the output load, or towed weight. When the converter clutch locks the fans together, the engine rpm will drop 700 RPM.

If we use a converter that is more efficient, such as a "low stall" converter, we will be able to achieve a higher efficiency rate. For example, an 88% efficiency rate would mean that the impeller would be turning 2500 RPM and the turbine would be turning 2200 RPM. When the converter clutch locks the turbine to the front cover we would only see a rpm drop of 300 RPM, as opposed to 700 RPM. A lower RPM drop is substantially easier on the converter’s clutch lining and will reduce glazing. In addition, because the fluid coupling of the converter is more efficient, more power, less heat and better fuel economy are delivered before the converter locks up.

STALL SPEED

To explain stall speed, let’s start with a true full stall. If the transmission were in drive, the brakes were held down so the vehicle will not move, and the throttle was held wide open, the torque converter will "stall" the engine at a certain RPM. When stalled, the engine will not be able to spin any faster unless the vehicle is allowed to move. This is a true full stall. We have specialized equipment which is used to perform this test. Do not test for true stall, it can damage shafts and overheat the torque converter.    

The next stall speed is generally called break away stall speed. If a truck is stopped on a hill and held in position using light throttle as opposed to brakes we are almost at the break away stall speed. If the engine RPM required to hold the truck was 1100 RPM and an increase to 1125 RPM started to move the truck then the break away stall speed is 1125 RPM.

The last stall speed is generally referred to as the flash stall speed. The flash stall speed takes effect under hard acceleration. From a standing start, if you were to floor the throttle, the engine would start to accelerate quickly and then pause at an RPM as it starts to pull the truck. If the engine went from idle to 1500 RPM in 1.5 seconds when floored, and then took another 2 or 3 seconds to get from 1500 to 1700 RPM, this would mean the "flash stall" speed was at 1500 RPM. When we lower the stall we want to lower the break away speed as well as the flash stall speed. This will make the engine work at a lower RPM for a given road speed and, in most cases, will increase fuel mileage. Once up to speed, the computer will command the lock up clutch on, and the driven fan will lock to the front cover of the converter. At this point the drive fan, driven fan and engine are turning the same speed which means all engine power will be delivered to the transmission and back to the wheels.

WHAT IS DIFFERENT ABOUT A GOEREND CONVERTER COMPARED TO OTHERS? 

We design our own converter components and manufacture them in-house. This ensures that our dimensions are correct and will work with your transmission. We build our converters in-house from start to finish. We make the billet covers, billet clutch dampners, billet stators, stator caps and more. We make our own billet front covers and clutch pistons out of forgings which greatly reduces any chance of porosity. Our stators are designed like an airfoil, this produces lift to help the stator rotate when going into the coupling mode and also creates a venturi effect to help torque multiplication. Our patented internal design insures that the torque converter clutch will lock up when the computer and valve body give the signal. No more feathering the throttle to get the converter clutch to lock up. We also use Raybestos and Borg Warner clutches in our converters. We feel it is hard to beat the quality and engineering capabilities of these companies that have been doing this since the early days of the Automobile.

Allison impellers and turbines are furnace brazed from the factory. Dodge impellers are also furnace brazed from the factory, however the 47/48RE turbines are not brazed from the factory. These parts are all brazed in a huge oven and when they vary in size and thickness, this can lead to “over-baking” smaller and thinner parts which result in warpage. We mig weld the fins on any turbine or impeller that has not been factory brazed and we never use any warped parts. If the fin angle must be changed on an impeller or turbine, we weld the fin in that position. It does take more time to do this but if you move a blade, it must be secured so it does not bend back to the original position or break.

HOW MUCH POWER WILL A GOEREND TORQUE CONVERTER HOLD?

With the proper valve body pressures, our triple disc converters can hold 1,400 HP and over 2,000 pounds of torque. Please contact us with questions regarding single disc converters.

HOW DO I DETERMINE IF I HAVE A GOEREND CONVERTER?

If your converter originated from Goerend there will be a series of numbers stamped into the converter cover. To find this series of numbers follow these steps:

ALLISON
1. Remove inspection plate.
2. There will be no drain plug. Rotate converter until you see stamping on cover.
3. Call us with the numbers and we can tell you the specifics on your converter.

DODGE
1. Remove inspection plate.
2. Rotate the converter until you see the drain plug.
3. There will be a series of numbers stamped next to the drain plug.
4. Call us with the numbers and we can tell you the specifics on your converter.

WHICH TORQUE CONVERTER CORES ARE ACCEPTED?  

STOCK & BILLET ALLISON STATOR INFORMATION

Billet Stators have a heavy duty stator warranty. Goerend billet stators are guaranteed not to break. We sell to many companies that re-sell our products. If you ordered a billet stator, here is one of the ways to check that it does have a Billet Stator: The following Goerend Converters have a billet stator: E, G, H, J, K, P, R, S, T, W, X The following Goerend converters have a stock stator: A, B, C, D, F, N.

CONVERTER REBUILD PROCEDURE 

1. The converter is drained and cut open.
2. All parts are cleaned and inspected.
3. Front cover, clutches, bearing, seals, & springs are all replaced.
4. All Dodge impeller hubs are newly replaced.
5. Impellers, turbines, stators, clutches, damper assemblies and billet front covers are all balanced individually.
6. The converter is assembled.
7. Various internal and external dimensional checks are made.
8. The converter is welded together by TCRS alignment equipment with sub-0.003 run-out.
9. The converter is leak-checked under water, under pressure.
10. The converter is then balanced as a unit and the run-out is checked again.
11. The total height is checked.
12. The internal end play is checked.
13. The lockup clutch is applied and checked for leaks and holding power.
14. The lockup clutch is released and the clutch and turbine are spun while the impeller is stationary to make sure the clutch releases properly and that there is no interference between any internal parts.
15. The hub is lubricated and a protector is installed.
16. New bolts are provided where necessary.

WHAT DETERMINES STALL SPEED?

The two major things that determine the stall speed are the engine torque and the torque converter. Here are a few different ways to think about it:

Lets say you are on an exercise bike that uses a large fan for the "load." The smaller the fan, the faster you can pedal it. The larger the fan, the harder it is to pedal it so your max RPM would be slower. With a small fan, you may be able to petal at 200 RPM and no faster, that means your stall speed is 200 RPM. With the large fan, you may only be able to petal at 50 RPM. The larger fan stalled you at 50 RPM with the same person on the bike. Two different fans, Two different stall speeds.

Now a professional athlete hops on the bike. With the big fan, they may be able to petal 100 RPM as opposed to your 50 RPM. To liken this to the engine and converter, you have to remember that the converter is nothing more than two fans, one fan is connected to the engine and the other is connected to the transmission. The fan that is connected to the engine blows oil at the transmission fan and when it blows enough oil at it the transmission fan will start to rotate, and the vehicle will start to move. In this scenario, with the engine and converter the same, if you install a converter with bigger fans, the stall RPM will be lower. With smaller fans the stall RPM will be higher, and if you add horsepower to the engine, just like the athlete, the stall RPM increases.

Now lets talk about air. It's all about the oxygen. A person on the bike can pedal harder at sea level than on the top of a mountain because they can breathe better. The closer to sea level, the more oxygen in the air. The air will be more dense, so will the engine. The engine is nothing more than an air pump that uses fuel. The fuel must burn, expand, and push the piston down. You must have oxygen to burn the fuel. The higher the elevation, the less oxygen we have, so the less fuel we are able to inject. Less fuel means lower power into the converter and therefore a lower stall speed. Normally, the higher the elevation, the higher the stall speed that is needed. The engine turbocharger also can make a huge difference. Like the converter, The turbo is also a set of fans, the drive fan is located in the exhaust of the engine and the exhaust flow makes this fan spin. The driven fan of the turbo is connected to the drive fan and sits in the intake side of the engine and forces oxygen into the engine so we can burn more fuel to get more power. When you have a turbo with bigger fans it takes longer to spool up and start to blow more oxygen into the engine. If it takes longer to spin up, it will take longer to get the oxygen into the cylinders to burn the fuel. This is called turbo lag.