Help need Lexus SC400 performance pulley system

[Peewee]

I can do back to back dynos for you and get 11hp difference.

When I tuned my car, we did 5 runs in the space of 15 mins.
Max power varied 15hp from best to worst.


And one pound reduction from the rotating mass 2" from the centre of rotation (ie from a crank pulley), is worth nothing compared to one pound reduction from the outer edge of a flywheel.

 

[Peewee]

Ok, for my own curiousity (and everyone elses here), I just weighed the stock pulley.
On bathroom scales (so could be a bit out), weighed in at a whopping 2kg or 4.5lbs.

Which is lighter than most lightweight pulleys.

I don't think you'll get it any lighter without sacrificing strength.

 

[Peewee]

In addition to the above, the MX83 7MGE Cressida pulley weighs 12lbs, and the 7MGE(GTE?) Supra pulley weighs 10.5lbs.

 

[xirforever]

So your suggesting that the reason they got good HP gains is becuase their pulley weighed much more than the stock 6lbs pulley? (david weighed it and said it was 6... maybe ill have to weigh it also) This would make sense.

Ok, for my own curiousity (and everyone elses here), I just weighed the stock pulley.
On bathroom scales (so could be a bit out), weighed in at a whopping 2kg or 4.5lbs.

Which is lighter than most lightweight pulleys.

I don't think you'll get it any lighter without sacrificing strength.

Thats only half of the mod.... the rest is pulley size. Plus if your scale is off and it does weigh 6 lbs, and we could make it 4, thats 2 pound difference, if the guy was right about 1 lb equal to 2.7 hp thats about 5 hp for JUST the weight difference, not inlcuding what the pulley size would do

I just think there is room for a worthwhile amount of HP that can be gained through underdrive pulleys. But if you dont trust dynos then im affraid even if these pulleys are made and good HP is gained, i wouldnt even be able to prove it to you becuase you seem to be too skeptical of this type of mod to believe the dynos.

 

[Lextreme II]

I weighted the pulley last night and it was 6 lbs.

 

[xirforever]

Does anyone know if the harmonic balancer is on the pulley that turns the belt for the timing? (1uz) This would be good news if so, then we dont have to worry about certain balancing and can make it as light as possible...

 

[Zuffen]

11 HP and a crank that rattles because it suffers from harmonics? No thanks

Do any members know what a crank does that runs without a balancer when it needs one?

It snaps!

Toyota didn't put on the balancer because it looked good. They put it there because it smoothed out the transient vibrations the crank gets at certain rpm. This can change with load so is hard to remove. Long cranks are worse than short cranks.

Back in the 1920's manufacturers used to refer to crank rattle as "power rattle" to make what was a nasty thing sound good. Once they figured out how to stop it they got rid of the expression. You will notice a lot of 4 cylinder cars don't have when built. The crank is short enough and stout enough to not need tham.

You drive a Lexus or use the engine for it's smoothe performance and longevity. Why would you jeoperdise both.

If you really want to save some horsepower remove 80% of the surface area of the main and big end bearings. They won't last long but you WILL see a powergain for a little while. That is essentially where you're headed with crank pulleys.

The 2.7hp per pound is selective. If I put 1lb on the end of your garden edger it wouldn't lose 2.7hp (it didn't have it to start with).

Given the cost and the reliability problems the gains are too little.

You can't make just any pulley to act as a harmonic balancer (they're actually quite sophisticated) so a supercharger pulley would have to be a bolt on unit or you could us a UZZ32 double pulley. I'd rather use this pulley (which I guess weighs 10lb and is built as a harmonic balancer) and play with the supercharger pulley than build a new one from scratch. The UZZ32 pulley is stepped so the outer section of the pulley is larger than the inner. Whilst I don't know I would guess the inner is underdriven and the out the standard size. If I used this I can have my cake and eat it to. Underdriven ancilliaries and the standard pulley for my supercharger. Peter Scott can tell us the sizes.

Machining up a pulley is easy in alloy. You'd have to hard anodise it to stop wear or it would last less time than the engine.

 

[xirforever]

"The 2.7hp per pound is selective. If I put 1lb on the end of your garden edger it wouldn't lose 2.7hp (it didn't have it to start with)."

i think thats why they were talking about cars and not weed wackers.... i could say if i add a pound of weight to my gas rc car will it loose 2.7 HP? obviously not. the statement was for car engines only.

As for the rest i agree that changing the crank pulley with the built in harmonic balancer is not a good idea unless you know what your doing. And yes i know if you take it out on a "not perfectly balanced crank" it can cause it to snap, like you said, very bad. But you can make underdrive pulleys for the other accessories which would not affect the crank in the slightest, and i think youd agree with me on that point. I was kinda hopeing someone would know more about these harmonic balancers than i do so we could make a crank underdrive pulley that is harmonically balanced with the crank. That would be ideal if at all possible. If not we can alwasy underdrive the water pump, alternator, and PS... those are also options, it would probebly not show good results tho unless you did all three. If we could balance an underdriven crank pulley instead of underdriving 3 pulleys it would mean youd only have to buy 1 pulley instead of 3. But if nobody knows anything about how to make a balanced pulley i guess ill start doing research. I would rather buy 1 pulley than 3....

 

[Zuffen]

If you made a smaller waterpunmp pulley what would yo do with the )now) too long cam belt? The tensioner can only take up so much slack.

The best way to get what you want is to make underdriven waterpump, P/S and Alternator pulleys out of alloy. This would save you weight and slow down the anciliaries.

If you want to go all the way machine off all the fences on the end of the pulleys. Assuming the pulleys are all straight you don't need them.

Don't forget 1lb rotating 4" from the centre of the crank is easier to rotate than 1lb 12" from the crank cenmtreline. If you plan to lighten anything always take it from the outside. This is usually the area under the least stress. You could probably gain a few onces off the harmonic balancer by machining off the ends.

My comment on the weed whacker is that a 454 and a 1litre wengine see 1lb as very different things. If I was to tell you I could give you a 20hp increase by changing your aircleaner you'd be happy. The fact the 20hp was made on the 454 doesn't matter. When you put the filter on your 1litre buxbox you certainly won't see 20hp. Internal combustion engines follow the same principles whether they are in a gas R/C or a D9 Caterpillar.

The bottom line is for the expense and effort to fit things like waterpump pulleys the gains will be just too little. If you want the car to go faster empty the trunk and go on a diet.

 

[turboandrew]

I have to agree with Zuffen and Peewee here. Why so much effort in maybe 5HP? And of course, that's if you are really lucky, because the only HP savings here is from reduced PS. Many of these cars have variable PS assist anyway, and it might be much easier to tweak that then mess with pulleys.

There is no real HP gain from less interia, just quicker revving and that's about it. If you want that, get a light flywheel.

 

[xirforever]

"The best way to get what you want is to make underdriven waterpump, P/S and Alternator pulleys out of alloy. This would save you weight and slow down the anciliaries."
-- Zuffin

exactly, thats what i had in mind

"The bottom line is for the expense and effort to fit things like waterpump pulleys the gains will be just too little. If you want the car to go faster empty the trunk and go on a diet."
--Zuffin

Already done, lol

I donno, i learned autocad 2005 and i also have the program, ive been making lots of things from the machine shop because i just cant get over how cool it is. We all know there arent many products out there for the 1uz, i thought this would be something i could do myself and provide it for other 1uz owners who are looking at how to squeeze out more power besides the obvious intake, headers and exhaust, and maybe a piggyback ecu. There arent too many options out there right now, i thought i could help. I was thinking about a flywheel too, but i figured id stick to one thing at a time so i can spend all my energy on one thing to make sure its perfect. Basically i thought i could help contribute to you all for your time and effort spent helping me. I might make the pulleys anyway (not the crankshaft one) just for fun becuase i like doing this stuff. I heard from friends about the pulleys helping them out i didnt see why it wouldnt on our cars (one was a 5.0 V8 the other a straight 6). I dont claim to know it all, so its quite possible that in the end if i dyno before and after that there would only be minumal HP increase and then again nobody is 100% sure that it wouldnt provide close to 10 HP.

Thanks for all your inputs, i think this was a VERY heated debate and a very productive one at that.

I guess ill let you guys know how it turns out in the end...

Now that we have fully covered this, sense the subject of lightweight flywheels has been brought up, what exacly do you guys think about lightweight flywheels? Are there any on the market for the 1uz (i havent seen any, doesnt mean there arent any tho)? It seems like it would be a fairly easy item to draw up. Only thing is the metal to be chosen would obviously have to be light but also very strong (anyone got any idea one what type?). Any comments?

Thanks, nick

 

[Zuffen]

Nick,

For a little more info on harmonic balancers go to www.precisionparts.com.au
These guys manufacturer balancers for a wide range of vehicles (no not for the 1UZ dammit) and if you look in thier performance section you will see that race balancers are up to 60% heavier than stock ones. Surprised me but you live and learn.

Looking at the 1UZ flexplate you couldn't lighten it anymore. It's like a dinner plate with 2" holes drilled in it!

I can post a photo of one (sans ring gear) so you can see what I mean.

As all 1UZ's running a flywheel have had them custom made we can all dial in the weight we want.

One thing to remember when lightening a flywheel it is better to take weight of the outside edge than the centre or across either front or rear. a few onces at the centre is useless but a few onces at the ring gear is meaningful.

 

[Peewee]

Xirforever.
You are forgetting that flywheels are only on manual cars.
1UZ's from factory are all auto's, so they run flexplates.
Flexplates are very very thin, and lightweight, so no chance of weight saving there.

Another thing to look at to make your car faster, is a shift kit for you auto tranny.
That will definately save you a good 1/4 to 1/2 a sec down the quarter mile.

But, as with everything, you sacrifice something for power, and in this case, its a little bit of comfort.

 

[xirforever]

Zuffen,
I checked out Precision Parts, wow they have some pretty well made stuff, i read through all their PDF's. They look like a great source to ask questions about these things. It would be great if they helped out or told me how to remake the stock one so its still harmonically balanced then i can add a pulley on the outside of it for a supercharger, and maybe underdriving. Ill let you know if i contact them and what happens.

"Looking at the 1UZ flexplate you couldn't lighten it anymore. It's like a dinner plate with 2" holes drilled in it!"
--Zuffen

lol damnit

Xirforever.
You are forgetting that flywheels are only on manual cars.
1UZ's from factory are all auto's, so they run flexplates.
Flexplates are very very thin, and lightweight, so no chance of weight saving there.

Another thing to look at to make your car faster, is a shift kit for you auto tranny.
That will definately save you a good 1/4 to 1/2 a sec down the quarter mile.

But, as with everything, you sacrifice something for power, and in this case, its a little bit of comfort.

Did some more reading, found out why flywheels have to be stronger than flexplates...which makes them more heavy. Like Zuffen said, learn something new everday, or a few things, lol

But ive decided i dont want to touch my transmision becuase im going to swap it out with a supra 5-speed manual(VERY affordable). Got it all planned out except where to mount the clutch cylinder. I'll figure it all out once i have it all together.... hopefully, lol. Ill have to make my own flywheel anyway, wahoo! However this wont be untill summer.

I'll let you all know when progress has been made on the pulley situation.
Can we say HOT thread?!?

 

[Peewee]

Just to clarify for you
Here is a flexplate

See how thin it is, and not much to it?
It would weigh something around the 5lbs mark.

Here is a flywheel, custom made, out of billet steel (the one behind my 1uz)

It weighs about 22lbs, and is about an inch thick (at its thickest).

However, you bolt a 20lb clutch to a 22lb flywheel, whereas you bolt a 50lb torque convertor to a 5lb flexplate. So there is an even out there.


Good luck with the manual conversion.
I'd be suggesting an R154 (surpa turbo) over the W58 (incase you were looking at the W58.) purely due to the heavy car it will be lugging around.

Manuals make the car much more spritely, and enjoyable to drive.

 

[xirforever]

Wow, those two plates are so different, no wonder they have different names, haha. But i guess your right, they would even out or get close once you add TQ and clutch. Manuals are SOOOO much more fun! i agree! You have the life of the car in your hands (and feet i guess, lol). Plus i figure if you keep top speed the same or under then adding another gear will mean the car is going to be quicker, not sure how much exactly though. And also not everybody will ask to drive you car cuz they wont know how.... haha there are positives to this all the way around, not sure about gas milage tho, probebly a little better, although the TQ in our cars do lock up, not sure how big of difference it will be. I'm going to stop there i guess becuase this has nothing to do with the intent of this thread...

Thanks for the photos though and advise

 

[Peewee]

You will rev higher on the freeway, as manuals tend to have a larger ratio 5th than the autos have for OD.

And OD ratio is about 0.68 or so. and the manuals is about 0.78.
So you will rev about 12-14% higher in top gear.

Mileage will probably be the same though, as you tend to use less throttle with a manual.

 

[Zuffen]

Peewee,

Excellent photos!

Zirforever,

Did you find the race and street weight differences the opposite to what you would expect? I know I certainly did!

If you want I can contact precisionparts and see if they are interested in making a balancer for thr UZ series. As we have a lot more UZ powered vehicles in Australia now (due to the Landcruiser) than in the past they may look at making one for us. The addition of a supercharger pulley would be as good as beer on tap at home!

Let me know if you want me to follow them up.

 

[xirforever]

Yes, i deffidentally found it puzzling on the weight differences, interesting stuff for sure. It never ceases to amaze me, anywhere you look on a car there has always been more than enough time spent on engineering it, and how complicated even the simple looking parts are. Example, crank pulley! lol

I think it would be beneficial to a number of poeple if they were to produce a supercharger pulley, so i say give them a ring and see what turns up, im also willing to call them if youd like, whatever floats your boat.

Cross your fingers guys

 

[Zuffen]

Precision Parts have agreed to look at making pulleys for us.

I need to send in a standard pulley and a UZZ32 pulley. For those that aren't aware the UZZ32 has a double crank pulley. The inner drive looks underdriven and the outer is the standard size. The inner drives the active suspension pump and could work well as an underdrive pulley and then use the outer for supercharging. This pulley arrangement mens the UZZ32 uses specific alternator, P/S and Air co due to the drive belt being further forward.

Photo below shows differences. The photo is off ALSC.

I can send the one off my spare engine and I'll contact Peter Scott to see if he has a spare UZZ32 one we can borrow.

Of interest they are currently working on underdrive pulleys for a raft of engines so our request comes at a good time.

You never know we may actually end up with the underdrive pulley we want without having to do the R & D and these guys really know their stuff.