jubay

iTrader: (2)

Hey guys,i'm thinking about getting a supercharger or my 1992 SC400,any suggestion on what brand,where can i order one from,any websites,the pros & cons on having a supercharger?thanks

Blizzy

iTrader: (-1)

Wow. That is a big question.

My advice is to search. There are a few of us doing forced induction projects on SC400s. I would also make sure you check out the Lextreme forums. There is more information on those forums about these pursuits than on the Club Lexus forums. Everything on Lextreme is V8 oriented.

The pros obviously relate to the power produced, fun had behind the wheel, etc. The cons would relate to the costs and potential unforeseen headaches that could pop up elsewhere on the car as a result of the making so much power.

In terms of design, Richwood Technologies and Rush Imports from Australia have designed manifolds that will work with Eaton M90 positive displacement superchargers. These superchargers can produce peak boost at any rpm based on how hard you are on the throttle. The torque production is incredible, in most cases, but these superchargers do have a tendancy to run out of breath on the top end. This is especially true if you are pulleying a lot of boost. The heat produced is intense and the overall efficiency can suffer. That being said, you can increase power production 50-75% and torque production 100+% with this type of blower. Eaton M90s themselves are relatively inexpensive, but the manifolds that have been fabricated to work with our motors are not cheap in the least.

Lextreme has made a bracket that will mount a centrifugal supercharger in an SC400 engine bay. This will require that you swap out the stock hydro fan for an electric fan, subsequently swap out the fan bracket from the motor, and relocate the battery to the trunk. Each of these jobs are mildly tedious but not terribly expensive. Centrifugal blowers themselves can be a bit pricey, however. The Lextreme bracket is drilled for a Vortech or Procharger supercharger. A Vortech or Procharger will be more efficient than the M90 on the top end, as the centrifugal design prodcues less heat. The centrifugal supercharger requires engine rpms to generate boost. You will not see peak boost until the redline and you may not see any boost until 2.5k rpm or more. Torque increases are less impressive than an M90 (+50-75%), but power production is more easy to come by (+50-100%) due to the blower design.

In either case, you should expect to spend at least $3000 on the upgrade and anticipate it being worth every last penny. I am in the midst of the centrifugal supercharger installation right now, and I anxiously await the day when I have it all running.

I hope what I wrote above gets you started... Keep researching, and you will likely setlle on a preposed set up that will satisfy your needs.

jubay

iTrader: (2)

Thanks Alot!

boobstar

i have yet to see or even hear of this done on a 300. what prevents this from being done?

Brendon

iTrader: (1)

I would assume because theres loads of turbo kits out there for the jz engines, after all the engine did come turboed from the factory. The only s/c kit ive heard of for the jz engine is by Vortech for the IS300. I assume it would work for the SC300, as long as it doesnt pertrude into the hood.

Mattmannz

The other thing you need to think about is the ECU.

I am doing an M90 setup now and plan to run the factory ecu, injectors and fuel pump. This means that I need to retain the cold start injector and the idle control valve for proper idle and cold start operation.

Typically these are deleted on lower end kits as aftermarket ECU's don't have to use these features to maintain drivability.

I am having a bunch of other fab work done on the supercharger to throttlebody adaptor to accomodate the idle control valve and getting the manifold drilled and taped for the injector.

I will have spent about 5K NZ or about 3.7k US to get my M90, two pulley's for 3psi and 6.5psi, bypass valve, lower manifold, manifold top plate, idler puller, new 6pk belt, throttle body adaptor, Innovate wideband AFR meter and gauge and a boost gauge.

Obviously there is a small amount allowed in there for some addition bits and pieces.

I also have access to some dyno time to run the car and make sure that the AFR is okay with the stock fueling, previous installs documented suggest that it will be okay and should net around 250-260kw with headers and a decent exhaust and a BFI.

Some of the engine plastics need to be trimmed a bit to provide some clearance but other than that it should be close to bolt on.

Bullet Cars do a complete kit for the factory ECU that has everything you need, this was about 5.5K US but would be guaranteed to be bolt on and work okay.

I chose the M90 because in my opinion the 1UZ lacks low down power and that's where a street car spends a lot of it's time. Mine is still auto for now so I wanted something extra down low.

I hope to start my install in about 4 weeks time - I am going to get the gauges in and running and replace the engine mounts and check vacuum hoses, do a compression and leakdown test and chuck the engine on a tunescope to make sure there are no problems before I start. I will create a build thread once it's up and running - the plan is to complete the install and dyno run in two days which should be possible.

Matt.

Brendon

iTrader: (1)

its nice to see so many people supercharging their SC400s, particularly with the Eaton M90. I know what you mean about the 1UZ lacking low end power. Even with a complete exhaust system, my car doesn't make any real power until around 3500-4000 rpm. The exhaust mods on work on the top end. When you're cruising and step on the pedal to downshift it sure pulls like a mf, but from a stand-still its got no pickup. I'm gonna try and high stall TC for now. I've heard they really help. I'm still saving up the 5k needed for the s/c kit.

twizted

iTrader: (2)

Ill have a richwood m90 kit for sale in about a month maybe less....

ScottURnot

iTrader: (33)

MArk (Blizzy) pretty much said it all. Its all about money. I am preparing to upgrade my M90 seriously. I have a lot in store, Just wait

twizted

iTrader: (2)

Part of me wishes i just left the m90 on with 5-6psi. No need to give it more fuel or a bunch of crazy tuning and stuff and it stays reliable, as well as being really fun to drive...

ScottURnot

iTrader: (33)

Dont go making me rethink my crazy plans!

twizted

iTrader: (2)

lol oops my bad

Blizzy

iTrader: (-1)

I would just like to take a moment to comment on this statement. It is nothing personal; but, I think there are a few common misconceptions at play...

First, a complete exhaust system can certainly bolster your low end.

The stock exhaust manifolds are relatively poor in all regards. If you were swapping them out, you could go with headers that have long primary pipes to bias the power band toward the low end. By choosing narrow diameter primary pipes, you would help bring peak torque production closer to idle.

In terms of plumbing, you could chose a pipe diameter that will operate efficiently at horsepower ranges equal to or less than the 1UZ's stock output. A 2" mandrel bent system would help move air more efficiently than stock on the low end while also not presenting any significant choke on the top end. Most n/a SC4 guys go with 2.25" piping, which only enhances the peaky nature of the 1UZ.

Second, the 1UZ motor itself is not designed to kick you in the teeth off the line.

The DOHC design is utilized for its efficiency of flow. Some Mustang guys swap their SOHC heads for DOHC heads from the Cobras to pick up gains on the top end. The DOHC design is particularly efficient at flowing the large amounts of air required on the top end.

The DOHC also has less rotational intertia than a SOHC head. This is excellent when accelerating, but when going from a dig, there is less mass to lever off of, making it harder to make torque down low. The same effect can be felt with a lightened or heavied flywheel. Light flywheels decrease rotating mass, which increases revability but that decrease in interia also makes torque production in the low rev range less overwhelming. Heavy flywheels, like that on a work vehicle, present more mass to lever off of from a dig, and increase the low end torque capacities.

To boot, the 1UZ has an over-square cylinder design, meaning that the bore exceeds in the stroke in dimension. More stroke means more torque. Diesel trucks have massive strokes and make tons of torque. A 2JZ has more stroke than a 1JZ and -thus- makes more torque. A 2UZ has more stroke than a 1UZ; it makes 215hp and 300+tq. In an extreme example, the 3L V8 motors in the Indy cars have extremely small strokes relative to the bore, which helps allow them to rev over 10k and keep making power.

How do you bolster the low end?

As mentioned, an efficiently chosen exhaust would do it. Another way to do it would be with an efficiently sized blower, like an Eaton M90 or Vortech V9. Scott and Twizted are using the M90. That blower will present no lag whatsoever and make peak boost right off idle, allowing for traction from a dig to become a major concern. KC95SC400 is running a Vortech V9. This is one of the smallest centrifugal blowers on the market, often used on four cylinder vehicles. But, boost is made so quickly with this blower than KC would need slicks to launch over ~2000rpm and not experience wheel spin from a dig. Heck, a smallish turbo like a 61mm would do the trick too.

That being said, there is no need to hate on the 1UZ for its inability to knock you into your seat from a dig: that was not the point. The motor was designed to be smooth and powerful. SOHC pushrod V8 motors that do most of their damage on the low end are certainly not smooth and powerful. Powerful? Yes. Smooth? Certainly not. The median Lexus buyer has never been interested in such a vehicle. The DOHC over-square bore design makes the 1UZ a rev happy V8, and that is part of the what makes it so loveable.

Whew. Let's get back to the thread.

vrsc400

iTrader: (1)

anyone running the Bullet Australia kit?
http://www.bulletcars.com/supercharg...er-system.html

twizted

iTrader: (2)

Not anybody that isn't in Australia i don't think. They said about a year ago they had a kit available and now there saying they are in r&d.

Everyone SCOTT has a super nice kit right now with everything for cheap. Why is everyone looking for more of the same old in-complete kits when there are ones out there for sale now that are complete for less...