Karl
10-05-2006, 03:18 PM
Edit:6 Oct 2006 - Added Fuel Delivery section.
Ok, so you have this supercharger in your car. And you've PROBABLY read that the Supercharger "sucks" compared to a turbo kit. Well, I'm here to tell you that's simply not true. While Superchargers are similar to Turbos in the fact that a larger supercharger kit is required for more boost (just like turbos have similar limits), the way they deliver power has a very tangible advantage. The linear nature of a supercharger is great for taking your opponent off the line, and if you do a few things to keep the air flowing, you can put a lot of turbo'd cars to shame :)
Here's a few topics of interest that I've run into with tuning my TRD Supercharged tC:
1. Heat soak from your intake
There's plenty of sources for heat soak. Superchargers HATE heat soak. While nice and flashy, metal intakes will heat soak, so don't do it. The 5whp gain you see on dynos with these intakes can be BEATEN by doing a couple of simple things with the stock airbox. For instance, open your stock airbox. Take the top shroud that has the carbon post-filter installed, and REMOVE the carbon element. Then swap your paper filter for a K&N and replace the carbon filter frame (that no longer has a filter). This actually netted me a very noticeable gain on the Butt Dyno(TM) There is an appropriate sized part for the TRD SC's airbox filter. While I don't have it on the top of my head, I'll follow up with a part number.
2. Heat soak from your exhaust
Yes, once again, flashy stainless steel headers look terrific - but they'll heat-soak your engine bay as well. At a bare minimum get some header wrap or one of those nifty new header "jackets" that attach with velcro and can be removed for shows. You want those hot EGT's to be as far down the pipe as possible and OUT of the engine bay. If you want to do it right, get the best Jet-Hot level you can afford. You'll have to send your headers out to them, but you will get a quality inside-and-out coating that will work wonders for keeping that heat out of your engine bay.
3. Belt Issues
I have experimented with a lot of different belts out there. When upping the boost, BELT SLIPPAGE IS ALWAYS A PROBLEM with certain belts. Here's the general rule of thumb - ALWAYS use a belt with a "solid" design (i.e. the 7 ribs of the serpentine are straight through and don't look like "dotted lines" like Dayco/Davis belts or Good year
Gatorbacks). The more boost & supporting mods, the more risk of slippage. The less rubber on the belt in the form of those "incomplete" ribs, the less contact with your pulleys, and the more chances of slippage - and so on and so on. GET A GATES BELT. THEY ARE ALL STRAIGHT THROUGH BELTS and don't do any of that silly "gatorback" stuff to cut costs. If you compare a Gates belt to another aftermarket belt, the difference in quality is simply amazing.
Recommended lengths and part numbers:
NST 12lb pulley: 7PK2234, aka Gates K070880, effective INSIDE length, 2235mm. The Gates K07882 may also work at a 2242mm inner circumference, but try to get the K070880 if at all possible, especially if you have the 20% alternator overdrive pulley. NOTE: Do NOT use the 12lb pulley with the TRD A/F map. You will run very lean and do some very real damage to your motor. You must use engine management to use this pulley. Also, make sure you upgrade your injectors. the 410's that come with the TRD kit are NOT enough to hit 300whp, and you will lean out!
NST 9.5lb pulley: 7pk2250 (K070882) or 7pk2260 (K070886) - both will work, however opt for the SMALLER one if you have a 20% Alternator Overdrive pulley.
4. Bypass Valves/Diverter Valves
The stock Bosch Bypass valve poops out at around 7psi. That's pretty much the most it will hold. The Bosch Sport 110 is better, but is only good for 10lb max - and at 9.5lb you're stressing it. You are absolutely at the upper limit that the 110 can handle. What you really want is the Forge 007. Yeah yeah yeah, it's a little over $100, but you will at least have the FLEXIBILITY to boost far higher than you are - even if you do another FI setup that benefits from a recirculation valve. Some people have even bought the HKS SSQV Bypass Valve with the Recirculation kit. This will work too, but is completely overkill for our applications.
5. Engine Management
When your supercharger is installed, you are changing out the fuel injectors for larger ones. This means the ECU has to be more conservative when pumping fuel through your rails. To facilitate this, they reflash your ECU with one that has a new Air/Fuel map supplied by TRD.
The TRD Air/Fuel map is absolutely horrible and is the biggest source of power loss in this package.
You want to get off this map as soon as you can. The easiest way to do this is to get a Greddy E-manage Ultimate and a Plug n' play harness which can be purchased from Dezod, then heading over to a tuning shop that has a dyno. You will net impressive gains just by correcting the A/F map at WOT.
That being said, do NOT attempt to run your SC with the stock fuel map. If you don't do the reflash, your injectors will be spraying gas like mad, making your car run very rich - meaning really poor mileage and a pretty fair amount of black smoke coming out of your exhaust. While the TRD map sucks for a lot of different reasons, it's still better than the STOCK map after you've upgraded the injectors.
6. Intercooling
Vortech Superchargers don't benefit much from front mounted intercoolers, or any other type of intercooler that adds additional plumbing. Additional plumbing means boost loss, and Vortech SC's hate boost loss. If you want the best option for intercooling our setups, the best way to do it is by doing Chemical intercooling via water/meth injection.
How it works is fairly simple. A pump is plumbed to your existing Washer fluid resevoir (which holds just around a full gallon). The pump is turned on and off via a controller that is T-Tapped into the vaccum hose that runs between the throttle body and the bypass valve - just like a boost gauge would be. You select a "minimum" boost that begins spraying your water/meth mixture. You also select a boost level where you require "maximum" spray volume (so far, you only need FULL spray at over 12lb, so this isn't much of a concern to us).
As you boost, when you hit your lower limit, the pump sprays water and methanol into your intake stream. The spray is a very very fine atomized mist that has two effects. First, the water cools the intake air, and most of it evaporates before it hits the combustion chamber. Secondly, methanol is a very slow burning alcohol which adds additional octane. This octane increase allows you to run higher boost levels since increased octane means less chance for pre-detonation to occur.
Until someone proves differently, it appears that water/meth injection is the only real intercooling we will need until someone makes a larger Supercharger fit kit for our cars :)
7. Cams
Well, it finally happened. RippMods is making cam regrinds for the Scion tC equipped with the TRD Supercharger. They free up additional power by adding increased lift and duration on the exhaust side of your valves. I tested the initial RippMods cam regrind for the TRD-powered TC and the results were impressive considering the other issues I had at the time. With major belt slippage and a leaky bypass valve limiting me to 6lb of boost, I was still able to hit 250whp with these cams. With new injectors, a new tune and a 12lb pulley (11lb effective), RippMods cams took my car to 311whp.
Just to note - since turbos benefit more from overlap (the duration where both your intake and exhaust valves are open at the same time), these cams will likely not offer a significant gain for turbocharged tC's - so don't bother rushing out to buy them unless you are SUPERCHARGED.
8. Fuel Delivery
You've added your 12lb pulley. You've slapped in a nice, thick Gates belt. You've got your Meth injection in. You've done your baseline tuning on your Greddy Emanage Ultimate. Your internals are STILL holding up.... but guess what?
Even with a decent tune, you're gonna lean out in your upper RPMs. What I've learned so far is that adding a larger fuel pump (like a Walbro 255lph) isn't enough - in fact, chances are it's not even going to be necessary. However you HAVE to increase your injector size. 550cc Injectors are the order of the day and will even work with your TRD updated fuel rail. What you want are the 550cc injectors made by www.deatschwerks.com (thanks to zer0 from SL, one of the few quality people left there). They are the same guys who make 'em for "ZPI", that crapbag shady company I can't stand. Get 'em from the source. At last check, $360 gets you a whole set shipped.
9. Other issues
There's currently a bracket breakage issue with the supercharger. The origin of this issue is still unknown. TRD is currently blaming "technician error" for these breakages, but the manual makes this portion of the installation unclear anyway. We're still waiting for this mess to pan out, but be aware you COULD break a mount even with a stock configuration. While this mount breaking isn't going to affect your daily driving, I'd take it easy until you can get it swapped. Images to a broken mount example are here (http://www.weckstrom.com/scion/brokenmount2.jpg) and here (http://www.weckstrom.com/scion/brokenmount1.jpg).
There's also a seal failure that's causing issues on a far fewer amount of SC's out there. The big problem here is that there doesn't appear to be a part number listed anywhere for these seals. You know you have this issue if you are leaking oil from your supercharger right around where the impeller pulley shaft meets the impeller bell housing itself. If you're leaking oil from that spot, it's a very bad thing and you'll want to hit up your Stealership right away for a replacement. At this time, there's no part number for just replacing the seals - you MUST replace the entire supercharger until a solution can be found.
I'll keep this post updated as I learn more about dealing with TRD's kit :)
Ok, so you have this supercharger in your car. And you've PROBABLY read that the Supercharger "sucks" compared to a turbo kit. Well, I'm here to tell you that's simply not true. While Superchargers are similar to Turbos in the fact that a larger supercharger kit is required for more boost (just like turbos have similar limits), the way they deliver power has a very tangible advantage. The linear nature of a supercharger is great for taking your opponent off the line, and if you do a few things to keep the air flowing, you can put a lot of turbo'd cars to shame :)
Here's a few topics of interest that I've run into with tuning my TRD Supercharged tC:
1. Heat soak from your intake
There's plenty of sources for heat soak. Superchargers HATE heat soak. While nice and flashy, metal intakes will heat soak, so don't do it. The 5whp gain you see on dynos with these intakes can be BEATEN by doing a couple of simple things with the stock airbox. For instance, open your stock airbox. Take the top shroud that has the carbon post-filter installed, and REMOVE the carbon element. Then swap your paper filter for a K&N and replace the carbon filter frame (that no longer has a filter). This actually netted me a very noticeable gain on the Butt Dyno(TM) There is an appropriate sized part for the TRD SC's airbox filter. While I don't have it on the top of my head, I'll follow up with a part number.
2. Heat soak from your exhaust
Yes, once again, flashy stainless steel headers look terrific - but they'll heat-soak your engine bay as well. At a bare minimum get some header wrap or one of those nifty new header "jackets" that attach with velcro and can be removed for shows. You want those hot EGT's to be as far down the pipe as possible and OUT of the engine bay. If you want to do it right, get the best Jet-Hot level you can afford. You'll have to send your headers out to them, but you will get a quality inside-and-out coating that will work wonders for keeping that heat out of your engine bay.
3. Belt Issues
I have experimented with a lot of different belts out there. When upping the boost, BELT SLIPPAGE IS ALWAYS A PROBLEM with certain belts. Here's the general rule of thumb - ALWAYS use a belt with a "solid" design (i.e. the 7 ribs of the serpentine are straight through and don't look like "dotted lines" like Dayco/Davis belts or Good year
Gatorbacks). The more boost & supporting mods, the more risk of slippage. The less rubber on the belt in the form of those "incomplete" ribs, the less contact with your pulleys, and the more chances of slippage - and so on and so on. GET A GATES BELT. THEY ARE ALL STRAIGHT THROUGH BELTS and don't do any of that silly "gatorback" stuff to cut costs. If you compare a Gates belt to another aftermarket belt, the difference in quality is simply amazing.
Recommended lengths and part numbers:
NST 12lb pulley: 7PK2234, aka Gates K070880, effective INSIDE length, 2235mm. The Gates K07882 may also work at a 2242mm inner circumference, but try to get the K070880 if at all possible, especially if you have the 20% alternator overdrive pulley. NOTE: Do NOT use the 12lb pulley with the TRD A/F map. You will run very lean and do some very real damage to your motor. You must use engine management to use this pulley. Also, make sure you upgrade your injectors. the 410's that come with the TRD kit are NOT enough to hit 300whp, and you will lean out!
NST 9.5lb pulley: 7pk2250 (K070882) or 7pk2260 (K070886) - both will work, however opt for the SMALLER one if you have a 20% Alternator Overdrive pulley.
4. Bypass Valves/Diverter Valves
The stock Bosch Bypass valve poops out at around 7psi. That's pretty much the most it will hold. The Bosch Sport 110 is better, but is only good for 10lb max - and at 9.5lb you're stressing it. You are absolutely at the upper limit that the 110 can handle. What you really want is the Forge 007. Yeah yeah yeah, it's a little over $100, but you will at least have the FLEXIBILITY to boost far higher than you are - even if you do another FI setup that benefits from a recirculation valve. Some people have even bought the HKS SSQV Bypass Valve with the Recirculation kit. This will work too, but is completely overkill for our applications.
5. Engine Management
When your supercharger is installed, you are changing out the fuel injectors for larger ones. This means the ECU has to be more conservative when pumping fuel through your rails. To facilitate this, they reflash your ECU with one that has a new Air/Fuel map supplied by TRD.
The TRD Air/Fuel map is absolutely horrible and is the biggest source of power loss in this package.
You want to get off this map as soon as you can. The easiest way to do this is to get a Greddy E-manage Ultimate and a Plug n' play harness which can be purchased from Dezod, then heading over to a tuning shop that has a dyno. You will net impressive gains just by correcting the A/F map at WOT.
That being said, do NOT attempt to run your SC with the stock fuel map. If you don't do the reflash, your injectors will be spraying gas like mad, making your car run very rich - meaning really poor mileage and a pretty fair amount of black smoke coming out of your exhaust. While the TRD map sucks for a lot of different reasons, it's still better than the STOCK map after you've upgraded the injectors.
6. Intercooling
Vortech Superchargers don't benefit much from front mounted intercoolers, or any other type of intercooler that adds additional plumbing. Additional plumbing means boost loss, and Vortech SC's hate boost loss. If you want the best option for intercooling our setups, the best way to do it is by doing Chemical intercooling via water/meth injection.
How it works is fairly simple. A pump is plumbed to your existing Washer fluid resevoir (which holds just around a full gallon). The pump is turned on and off via a controller that is T-Tapped into the vaccum hose that runs between the throttle body and the bypass valve - just like a boost gauge would be. You select a "minimum" boost that begins spraying your water/meth mixture. You also select a boost level where you require "maximum" spray volume (so far, you only need FULL spray at over 12lb, so this isn't much of a concern to us).
As you boost, when you hit your lower limit, the pump sprays water and methanol into your intake stream. The spray is a very very fine atomized mist that has two effects. First, the water cools the intake air, and most of it evaporates before it hits the combustion chamber. Secondly, methanol is a very slow burning alcohol which adds additional octane. This octane increase allows you to run higher boost levels since increased octane means less chance for pre-detonation to occur.
Until someone proves differently, it appears that water/meth injection is the only real intercooling we will need until someone makes a larger Supercharger fit kit for our cars :)
7. Cams
Well, it finally happened. RippMods is making cam regrinds for the Scion tC equipped with the TRD Supercharger. They free up additional power by adding increased lift and duration on the exhaust side of your valves. I tested the initial RippMods cam regrind for the TRD-powered TC and the results were impressive considering the other issues I had at the time. With major belt slippage and a leaky bypass valve limiting me to 6lb of boost, I was still able to hit 250whp with these cams. With new injectors, a new tune and a 12lb pulley (11lb effective), RippMods cams took my car to 311whp.
Just to note - since turbos benefit more from overlap (the duration where both your intake and exhaust valves are open at the same time), these cams will likely not offer a significant gain for turbocharged tC's - so don't bother rushing out to buy them unless you are SUPERCHARGED.
8. Fuel Delivery
You've added your 12lb pulley. You've slapped in a nice, thick Gates belt. You've got your Meth injection in. You've done your baseline tuning on your Greddy Emanage Ultimate. Your internals are STILL holding up.... but guess what?
Even with a decent tune, you're gonna lean out in your upper RPMs. What I've learned so far is that adding a larger fuel pump (like a Walbro 255lph) isn't enough - in fact, chances are it's not even going to be necessary. However you HAVE to increase your injector size. 550cc Injectors are the order of the day and will even work with your TRD updated fuel rail. What you want are the 550cc injectors made by www.deatschwerks.com (thanks to zer0 from SL, one of the few quality people left there). They are the same guys who make 'em for "ZPI", that crapbag shady company I can't stand. Get 'em from the source. At last check, $360 gets you a whole set shipped.
9. Other issues
There's currently a bracket breakage issue with the supercharger. The origin of this issue is still unknown. TRD is currently blaming "technician error" for these breakages, but the manual makes this portion of the installation unclear anyway. We're still waiting for this mess to pan out, but be aware you COULD break a mount even with a stock configuration. While this mount breaking isn't going to affect your daily driving, I'd take it easy until you can get it swapped. Images to a broken mount example are here (http://www.weckstrom.com/scion/brokenmount2.jpg) and here (http://www.weckstrom.com/scion/brokenmount1.jpg).
There's also a seal failure that's causing issues on a far fewer amount of SC's out there. The big problem here is that there doesn't appear to be a part number listed anywhere for these seals. You know you have this issue if you are leaking oil from your supercharger right around where the impeller pulley shaft meets the impeller bell housing itself. If you're leaking oil from that spot, it's a very bad thing and you'll want to hit up your Stealership right away for a replacement. At this time, there's no part number for just replacing the seals - you MUST replace the entire supercharger until a solution can be found.
I'll keep this post updated as I learn more about dealing with TRD's kit :)