Help need Lexus SC400 performance pulley system

[xirforever]

Great work Zuffen! Sounds great, and what a speedy job you did too! Keep us updated

 

[COFFEE]

Guys, guys, guys.
As it has previously been pointed out. people will beleive anything they hear and follow a trend.
I am no mechanic and could not build a high performance motor buy myself with out some assistance but i can tell you this:
You can not touch the water pump or when at idle for short periods the thing will get hot on a hot day.
The altenator you would gain stuff all for the slight decrease in pully size, or that could cause you some issues being a car that has got to be the most electrically power demanding car around for its age.
Power steering pump isn't going to give you much either with out failing.
I mean Peewee is right, for the cost and hassil involved to gain 9/10ths of stuff all, you gain it somewhere else and futher more say you did gain some crazy figure like 10Kw you would be hard pushed to notice it !
I mean these people who use these systems properly and really get any benifit and would say its worth it are Top Fuellers etc.
These guys are looking for every ounce of weight they can strip and looking for half a HP.
I used such a thing on my previous car simply to replace the V belt with a ribbed one for reliability and lack of slip.

Regards

Stephen

 

[Peewee]

You can not touch the water pump or when at idle for short periods the thing will get hot on a hot day.

FYI Stephen, the waterpump runs off the cambelt, not the accessories belt, so there is no saving there even if the crankpulley was made smaller

 

[COFFEE]

Peewee,
My mistake.
Personally i find the power steering far to soft and i would rather feel the road so i simply disconnected the computer module for the Steering.
Its fitted under/ behind the glovebox.
Feels alot heavier but alot more responsive, still didn't notice any power gain assuming the pump is working less hence the heavier feel.

Regards

Stephen

 

[COFFEE]

While i have you guys,
Being a tight ass and the miss's against anymore money being wasted on cars.
I wanted to get the power up about the 250Kw mark as cheap as possible ( with out her Feeling the missing dollars ).
I was looking at going forced inducted but with two sc14 superchargers ?
Simply for the reason that i can buy two for $500 and i reackon i could have it all running for around the $2000 mark ?
I have tried to compensate for the extra drag on the motor buy removing the hydraulic clutch fan and replacing it with two electric items. Further more sliding the radiator on a forward slant to accomadate the blowers in front of the engine and use probably the pulley shown earlier of the other model.
Do you think this should work and make this power ?

Regards

Stephen

 

[Peewee]

You won't get 250kW without an aftermarket ecu

 

[COFFEE]

Peewee,
Well i must admit i did question this before and got a reply that the standard Ecu will handle a power increase upto 40% which should put the total output figure around the 270Kw mark ?
It does sound a little out their but so is everything about this car !
If this is true thats great, if not the Ecu is no concern other than the extra dollars.
My real concern is how efficent these blowers are ?
I know they are very small but the two of them should be good for say 7psi its just temperature increase and i really have no idea how much power the two of them will drain from the engine ?

Regards

Stephen

 

[Peewee]

You won't do it with the SC14's, you will need an M90.

That 40% was worked out that pre-supercharge was 121rwkw, and post supercharge was 171rwkw.

That 121rwkw seems a bit low for a stock 1uz, its a 35% power drop from the flywheel.
25% is the max you should assume.
His 171rwkw will be about 220-230kW at the fly.
Stock these motors are only 185kW.
Its the vvti that was 208kW

I'm pumping out 180rwkw NA, and I'd say its about 230kW at the flywheel, if not a little less.

 

[COFFEE]

Peewee,
I have a 94 model and have told 194Kw.
I worked out the 40% on that ?
I realise the m90 would be a greater unit but i think the two sc14's would do the job.
A hell of a lot better for the price.

Regards

Stephen

 

[Peewee]

40% is a big ask with $600 worth of superchargers.

Don't you think that if it was possible, people everywhere would be doing it?

You will only pull about 4psi out of them, and that is overdriving them to a safeish limit (read: they wont last 100,000km's).

At 4psi (which you will get at almost redline), you will be lucky to get a 30kW increase.
And that is only on peak power.

Over the whole range, there will be minimal increases

 

[COFFEE]

Pewee,
Well you might be right ?
I can't find a great deal of info on these superchargers, well no spec's just a lot of talk.
Talk is often peolpes opinion rather than facts or worthy knowledge.
Firstly people wont look at these items for this application due to there size.
Castlemain Rod Shop uses these blowers on 3.8ltr 6 cylinders and claims a 25-30% power increase with standard pulley and an exhaust no chip ?
I don't know of anyone who has used this kit to verify it's performance ?
I would imagine 35Kw power increase with exhaust in this application possible.
If so this means the blower can supply atleast 170Kw ?
Q1: How much power did the orginal motor this Blower came off ( 1G-GZE ) have ?
Q2: Can it supply it again ? because i am looking for 270Kw, which sounds like a lot but when you work it out is only 135Kw per 2ltr bank.
Pretty close to the original spec's ?
Q3: How much power loss do i get from using two of them on the motor ? this is the the answer not known !
" 40% is a big ask with $600 dollars worth of superchargers "
If somebody put to me the same statement 40% from $500 worth of blowers because that what i can buy them for, i would reply " yeah right "
I am just looking to make some reasonable power from a very susseptable motor with the least amount of cost.
The she keeps telling me, priorities !
Look if you can point me in the direction of any proper spec's about these Blowers, i would be greatfull.
Others wise all you have said is, it sounds crazy and rediculous. I havn't seen any supporting information as to why ?
A car was designed to drive you from A to B safely, the idea of supercharging one to make it capable of getting you into dangerous situations is crazy !

Like is said i would be happy to look over any facts you have.

Regards

Stephen

 

[Peewee]

Here's a few quotes from other people, none that I can personally verify though.

Hmmm i happen to have seen a SC14 run on a 3.8 commo v6, was running about 3.5 psi. The commodore has a bucket of torque now when it was on, but these chargers have no balls up top, they just tend to run out of puff when you rev the motor out. Though for the price it gives a fairly good performance return.

there is a kit from castlemaine rod shop that adapts the SC14 to the commodore V6 (3.8L) and runs 7psi of boost.

I'm quite aware that people have put SC14's on big engines, but I can assure you those SC14's won't last long. Inlet temperatures will be horrendous also. All superchargers are designed to work efficiently in a very specific airflow/pressure envelope, just like turbos, and if you try to push them too far out of that envelope things will start to get ugly.

I'd also suggest that, especially in the case of the 3.8 V6, the restrictive cylinder heads make it behave like a much smaller engine at high rpm. Remember boost is simply a function of the air NOT going into the engine. More restriction = more boost!

...but why do they work on the 3.8L V6s and RB30Es all the way to redline?

The limited anecdotal evidence I have suggests they are actually very disappointing.

Here is some maths, assuming 4psi boost.

so 11000rpm x 1.4L = 15,400Lpm

for 2L, 15400/2= 7700rpm MAX (for NO BOOST)

for 3.5L, 15400/3= 4400rpm (for NO BOOST)

for 4L, 15400/4 = 3850rpm... this is with ZERO boost!!!

to run 4psi on a 1UZ with 1 SC14...
4/14.7 = 0.272BAR.

4L x (1+0.272) = 5.09L effective capacity.

15400/5.09 = 3025...

so with 1UZ, and 1 SC14, you are limited to 3025rpm with 4psi boost, and above 3850rpm, the SC starts pulling vacuum!!

with 2 SC14's, (15400+15400)/5.09 = 6050rpm!!

so even with 2 SC14's you are still limited to 6050rpm, and 7700rpm before you start pulling vacuum!!!!

4A kit, 12psi on a 1.6L is (1+12/14.7)x1.6= 2.9L cap
12psi on 1G = (1+12/14.7)x2.0= 3.63L effective capacity.

at 6000rpm, 3.63x6000=21780Lpm.

21780/1.4L=15557rpm for the SC14!!!!!

same kit on 4.0L V8 at 4psi
21780/((1+4/14.7)x4)= 4280rpm......
so even with the TRD kit, and overdriven SC14, you can still only get to 4280rpm with the SC14 on a 1UZ at 4psi.

If the maths doesn't makes sense to you, don't worry.
But the guy who wrote it knows his stuff.

 

[Lextreme II]

Here are some pictures i told few days ago.

 

[Zuffen]

Personally I wouldn't fit underive pulleys as I think they are a waste of time. But if I can help I will.