roots blown gs430
not gonna produce anything. first off, im not allowed to sell any manifolds on club lexus per forum moderator message i received once. second, once it's all said and done it'll cost more than the average person wants to pay. i'd have to charge like almost two grand just for the manifold to make it worth my time. if someone is up for it than I can start one tomorrow but based on what I've seen on these forums, its rare for someone to fork over that kind of cheese. But if someone was ready to transfer money via paypal. The machining would begin tomorrow. I have three other manifolds sitting in my garage ready to go.
5psi from a turbo makes way more power than 5psi from a positive displacement supercharger. but it really boils down to personal preference. and what sound your looking for. turbo whistle or supercharger whine. both sound beautiful.
Update
I'd like to give an update as to how the car is running. Amazingly well for it being supercharged on stock fueling and computer. i would recommend to anyone who is interested in doing it to their car. I've done plenty of data logging with my scan tool and verified the computer is happy and even with 150 degree intake temps. at five psi. the stock timing is still holding strong at 20 degrees advance indicating no timing is being pulled. which means that the knock sensors aren't picking up any detonation. the meth. injection has been another story though. trying to fine tune the meth. delivery being based off the boost pressure. I've discovered that 5psi at wot and 150 degrees (hottest i've seen) doesn't warrant very much need for meth. to be sprayed. in fact i've noticed power is lost when the meth kicks in with too big a nozzle. I've had to install the smallest nozzle the kit came with which is 200cc and back my pump output down to where it only delivers 300cc's at wot. that seems to be the sweet spot. So before I go putting a smaller pulley on for more boost, Im going to ditch the exhaust system currently on there for a complete cat back 2 1/2 inch all the way back with mandrel bends and an x pipe. that will ensure the engine is flowing well in and out. than get the vb upgrade done from ipt transmission. once thats done, than it'll be time for more boost. and the potential problems that may bring. stay tuned.
Any special reason why you didn't install a intercooler on this set up ? Why not dyno it now the way you have it and then again after going with higher boost and x pipe. Would like to know the difference for maybe future references 
its about 100 a pop for each dyno run. yes it would be interesting to see before and after but ill just wait until the exhaust is on than dyno it. than once i pulley it down to 7-8psi than ill redyno it.
2 1/2 inch exhaust
Had time at work to put together all my mandrel bend pieces from columbia river for my exhaust system. its 2 1/2 all the way back from the cats with a custom made x pipe going to some older magnaflow mufflers. I was expecting a night and day difference but it seems like a waste of money. it's only louder than before but performance wise, even after a few days of driving, I don't believe any performance gains came from putting larger exhaust on it. I know it didn't cost me any low end torque because it will destroy the tires all the way to redline still but the topend actually seems to be a lower output. which is weird because its my understanding that scavenging is not so much an issue when you have a supercharger. SO, that being said maybe 2 1/4 inch would have been a better bet. But, I did step up the exhaust to 2 1/2 inch because I plan on increasing the boost shortly so maybe the performance will benefit once more power is being made. But don't get me wrong, the car is still a blast to drive. once the valve body upgrade is done, it ought to be awesome.
Lexus Test Driver
Joined: Dec 2006
Posts: 1,509
Likes: 6
From: NT
Had time at work to put together all my mandrel bend pieces from columbia river for my exhaust system. its 2 1/2 all the way back from the cats with a custom made x pipe going to some older magnaflow mufflers. I was expecting a night and day difference but it seems like a waste of money. it's only louder than before but performance wise, even after a few days of driving, I don't believe any performance gains came from putting larger exhaust on it. I know it didn't cost me any low end torque because it will destroy the tires all the way to redline still but the topend actually seems to be a lower output. which is weird because its my understanding that scavenging is not so much an issue when you have a supercharger. SO, that being said maybe 2 1/4 inch would have been a better bet. But, I did step up the exhaust to 2 1/2 inch because I plan on increasing the boost shortly so maybe the performance will benefit once more power is being made. But don't get me wrong, the car is still a blast to drive. once the valve body upgrade is done, it ought to be awesome.
The 2.5" will be nice to have for future power mods, around 400-500hp range. I think the most noticeable effect for higher RPM power was removing the third cat from our system, deleting the Y pipe if wanted, and running better flowing mufflers in the back.
