The TRD Supercharger is a nice piece of kit. Magnuson and TRD should be proud of this product as it is quite thoroughly put together. However, I do suspect that some performance has been left on the table. This thread is all about finding and developing that extra power.
It should be noted that the 3UR-FE is around its comfortable limit at 504 hp. Going past this point is pushing the pistons and rods past their design limits. These parts may last for while under the extra load, or they may not... I suggest building the engine further when going past the stock TRD hp point.
First, we'll start with what looks obvious... the throttle body. When Magnuson designed this kit, it does appear that they wanted a larger throttle body to feed the Eaton TVS R1900. One can see this was planned by looking at the intake snout.... more specifically the flange that the throttle body mounts to. The tube is about 88 - 90 mm, yet it steeply necks down to 77 mm at the inlet flange to accept the TB (the throttle blade measures 76mm). The neck down can be seen in the below photo, which is taken from inside the snout.
This flange can easily be machined out to accept the properly sized unit. The problem is we need to manufacture a throttle body of the proper size. The stock throttle body can not be bored much further than stock due to the architecture of its build. Going more than roughly 2 - 3 mm larger will start to get close to the cavity where the DBW electric motor sits. So, it's off to the drawing board.... more to come.
Just noticed the thread. I am working on just this on my Supercharged Lexus SC430. I have to convert the engine from DBW to cable. So at first my friend gave me a 75mm BBK. It seemed to be all I needed since like you said the SC is bored only to 76mm. It just looked too small with the BBK so I ordered a 90mm and it seems to be perfect. I will post up photos later tonight of the new TB up to the SC. I see what you are saying too that the SC seems to have room to bore out to 90mm easily. I think I am going to tune on E85 and I think we are going to make great reliable hp. That is what I am looking for too in the race car. Reliable HP.
As promised here are pics of my 90mm up to the SC. What I noticed is that if you machine out the SC to the outer part of the o-ring relief it should be right at about 90mm. It also seems like that is what the inside diameter of the SC is really supposed to be. However, since the factory Tundra's TB is 75mm then the actually brought the diameter in to 75mm. I understand why they did it but I think there is more to gain here.
So are you going to pull the trigger on the bigger bore, I still favor the LS3 TB with the translater box, but I think the Ford Coyote 5.0 TB bolt pattern might be closer but I don't know what size you can get them.
I think what I am going to do is open up the inner diameter on the SC to 90mm. What it means is that if I ever want to sell it then I most likely will get a crap load less but all in the name of science. LOL
Gains will vary depending on mods, and at this point, they will would pure speculation, so no numbers. I already have the long tubes on, so whatever gains my truck produces will be with those in place.
Mailhot, good info, thanks for contributing. Porting out the sharp transition shouldn't drop the value. A stock throttle body could be tapered, or a short properly transitioned spacer would probably give it better performance even with a stock TB.
I would prefer to use the stock electronics w/o a translator. Unfortunately, the decision to leave the stock throttle body was likely to keep costs down... let's see where we can get to.
This is some good stuff, Im sure with pulleys alone this motor can make 600hp using the supercharger. Now that you guys are testing out how to make the SC more efficient it can probably make even more than that. Turbos are nice but nothing like the instant boost from a supercharger.
Do any of you guys do before and after chassis dyno runs? The old Seat of the Pants dyno isn't very accurate; however, comparing 1/4 mile drag slips can be pretty accurate --especially with Quarter Jr. software.
bjowett, do you know what size tubing they used in the long tubes? I think the exhaust header flange holes are bored out to 1.75" However, I think the factory manifolds go down to 1.5" I really hope the long tubes remain 1.75". That would be awesome. I have to modify a set for the Lexus shortly.
This thought popped into my head...is it possible they wanted to increase intake velocity at the cost of intake volume? Would there be a gain for velocity or is it all about pure volume of flow at the intake? :dunno:
Is it comparable to ported heads? Is there ever a trade off when you increase flow? I know you can do more harm than good if you increase turbulence but if it's smooth air, the more the better?
The TVS R1900 will support over 700 hp. Can the fuel system keep up at that point? :lol5:
As of now, no dyno for this part.... BUT, if it works, we will see more boost... and that is easy to measure. We can also measure airflow through the 97mm airflow meter.
The long tube headers are 1.5". I don't believe there is anything on the market with larger primaries... so you will be on your own to fabricate them.
As for velocity, this situation is a bit different than a normally aspirated cylinder port. To a point, we want to be able to feed the super charger rotors as much air as they can grab.
I just mounted the 90mm tb. I still have to bore out the TRD supercharger to 90mm. Will be doing it tonight. I was just going to post these to my SC430 thread but it seems like they might do this topic well. Also, I don't mean to hijack the thread I just know it's going to be kick ass.
Let me remind everyone too that this is going in a race car running an AEM standalone. You can't just bolt this up to your Tundra and go. Doing so would most certainly void your warranty and not work! You may be able to find another Drive-by-wire TB that is 90mm and make it work. However, this would not apply to me.
90mm compared to the 75mm OEM.
In this photo you can see the section of the TRD Supercharger that will need to be machined away to take full advantage of the 90mm TB.
Another crazy fact I just found. The Titan VK56 TB is almost identical to the 3UR! I had to run out but I will get some pics posted shortly. Don't get too excited though. It's smaller than the Tundras. Good for Nissan fans though.
LOL, funny you mention that! A friend of mine just purchased a Titan... and I did notice the throttle body. The Lexus IS-F uses a nearly indentical unit to the Tundra, same diameter...
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