Confirm understanding of lightweight mods

[SuperTom]

Originally Posted by 86TOYO2k17

OK, i was thinking of underdriving the alt to slow down the charge if it was an issue, may still do it anyways to squeeze out that extra 1/2hp

Yes i am really lazy, but you are right i shouldn't let my laziness get the best of me. def on my list of mods to do.

Going to probably copy your battery setup exactly.

wasn't just you a few others complained about changing battery.

Let me know if you need help figuring out how to make the battery cage. Its pretty easy to see how it works when you have those home depot parts in your hand

[churchx]

Originally Posted by 86TOYO2k17

I think stock battery was like 390cca and 90AH, this batter is like 520cca and 34AH, so i think it should be fine in the winter.

In EU stock battery was 48Ah. It failed for many though and in such cases replaced for Toyota for free with 65Ah 590A one (IIRC P/N: 28800-YZZJA or 28800-YZZJB). Stock still came 48Ah, but it might be not sufficient to eg. week not driven car in winter unless you recharge it separately. That might be simple process for someone with own garage or hause, but if one lives in multiapartment house and first has to walk to far parking spot .. i don't think regular battery changing and carrying it forth and back for half a mile and then having fuel trims reset is that enjoyable process instead of hopping in and driving to work

[86TOYO2k17]

I already have a fluidampr I need to install, and I was thinking about installing an alt/water pulley at same time.
However I want to use the fensport alternator pulley which is 10mm oversized for underdriving the alt. Mathematically in theory should had .65hp + be lighter. Does anyone know if the stock belt has enough slack, or tensioner pulley can be loosened to accommodate this 10mm larger diameter? Or do I really need to get a 10mm longer belt if I wanted to do that?

[Joesurf79]

Originally Posted by Tcoat

The minuscule advantage that a light weight pulley offers is lost the second the car is put in gear. Any gear. As soon as the engine has to rotate a flywheel, clutch disc, transmission gears, drive shaft, differential, axles, wheels and all the shafts, joints and other moving parts involved the fact that you saved a pound in rotating mass in a pulley isn't even noise much less measurable.

No matter what anyone feels in neutral in the driveway, the physics are inescapable. The need for damping is paramount, no matter what anyones matketing dept says about the factory pulley's function. I have seen first hand how things go sideways when vibrations get out of hand on high horsepower, industrial rotating equipment. It's ugly

Controlling higher order harmonics means more to me than blue anodizing. Fluidampr, all day long. Track car gets UOA after every change (every 3rd event) and there is almost no bearing wear metal after 2years and somewhere north of 7,000 miles on track. (24k miles total on car).

[nikitopo]

Originally Posted by 86TOYO2k17

I already have a fluidampr I need to install, and I was thinking about installing an alt/water pulley at same time.
However I want to use the fensport alternator pulley which is 10mm oversized for underdriving the alt. Mathematically in theory should had .65hp + be lighter. Does anyone know if the stock belt has enough slack, or tensioner pulley can be loosened to accommodate this 10mm larger diameter? Or do I really need to get a 10mm longer belt if I wanted to do that?

I have a similar size alternator pulley. There was a new belt in the kit, but when I compared it with the oem belt I couldn't see any difference.

Originally Posted by Joesurf79

I have seen first hand how things go sideways when vibrations get out of hand on high horsepower, industrial rotating equipment. It's ugly

On a boxer engine?

[churchx]

86TOYO2k17: you probably meant - undersized? Oversized needs to be the pulley that turns other things, in this case - only crank pulley. Rest need to be same or undersized, to be driven at less rpms per same engine/crankshaft pulley rpms. AC, alternator pulley - "accessory pulleys" that are being turned, not doing turning, to free up engine energy used for that.
Though pulleys that don't spin anything but spin freely and are there only to tension belt, may aswell be oversized. But there is close to no gains to that, rather slight weight gains.

[nikitopo]

Originally Posted by churchx

86TOYO2k17: you probably meant - undersized? Oversized needs to be the pulley that turns other things, in this case - only crank pulley. Rest need to be same or undersized, to be driven at less rpms per same engine/crankshaft pulley rpms. AC, alternator pulley - "accessory pulleys" that are being turned, not doing turning, to free up engine energy used for that.
Though pulleys that don't spin anything but spin freely and are there only to tension belt, may aswell be oversized. But there is close to no gains to that, rather slight weight gains.

There is another method. Keep the crank pulley size same and oversize the peripheral pulley you want to underdrive. This method has the advantage to not underdrive all the peripherals. For example you can underdrive the alternator, but not the water pump.

[churchx]

Ouch. Somehow it messed up in my mind and came out opposite. Right, for same belt speed driven accessory pulleys need to be oversized to turn slower. And driving (crank) pulley needs to be undersized to turn all driven pulleys slower at same rpm.
BTW, any nfo, how much each driven accessory uses up power, and which are more & which are less safe to slow down (and within what range)?

[humfrz]

Originally Posted by churchx

Ouch. Somehow it messed up in my mind and came out opposite. Right, for same belt speed driven accessory pulleys need to be oversized to turn slower. And driving (crank) pulley needs to be undersized to turn all driven pulleys slower at same rpm.
BTW, any nfo, how much each driven accessory uses up power, and which are more & which are less safe to slow down (and within what range)?

(not directed at you, churchx)


I'm thinking that some folks didn't spend much time with an erector set as kids …


humfrz

[86TOYO2k17]

Originally Posted by churchx

Ouch. Somehow it messed up in my mind and came out opposite. Right, for same belt speed driven accessory pulleys need to be oversized to turn slower. And driving (crank) pulley needs to be undersized to turn all driven pulleys slower at same rpm.
BTW, any nfo, how much each driven accessory uses up power, and which are more & which are less safe to slow down (and within what range)?

This is from another thread.

“std crank pulley is 143 OD, alt pulley is 57.5 and water pump is 132

alternator is 130Amp @ 14v = 4.4Hp to turn assuming 55% efficent and due to the pulley ratio its running @ 2.5 x crank speed

so adding 10mm ( Fensport pulley) reduces the ratio to 2.12 so 15% slower = 3.75 Hp to turn so + 0.65hp gain

Water pump std ratio is 1.08 with fensport pulley is 0.94 and water pumps typically take 7bhp to turn so again about 15% slower so 6 bhp to turn so 1 bph gain so in total, you should get about 1.6bhp gain”

Now at first I didn’t like the idea of underdriving the water pump but apparently alot of guys on the uk forums have been doing it with no problems and fensport claims it has no negative effect on engine temps. So now I’m thinking of just getting both and using new belt. Can argue the effects of lightweight pulleys. But oversized/underdriven pulleys do give some gains.

[churchx]

86TOYO2k17: it seems to me that also that it might be safe at track to underdrive generator, as after all, for track prep one can precharge battery, and will drive at much higher rpms then when daily driving. And possibly with AC/music off.
Water pump .. but what if one turns up fans in tune to cool coolant more to somewhat compensate slower pumping speed? And if there is oil cooler installed?
There is possibility of also having much redundancy/extra in standard setup of standard car, designed in by manufacturer that may have wished much higher safety margin then minimally necessary. Manufacturer also may have chosen parts from it's part bin of maybe ones optimally fit for other cars, to save on R&D and manufacturing.
But again, i don't have any real data, hence why i asked, how much power is used up in turning generator, how much for A/C, for water pump, so thanks for posting that. Would like to know in addition to that what is considered to be safe in underdriving. Aand, then again i'm not considering even in future do overdriven/underdriving mods .. it just seems interesting topic to hear more about for one wishing to learn more about cars . Prefering to have that (even though redundant) safety margin in, even more so as mentioned gains seem too small to bother.
EDIT
btw, what do you think of underdriving/undersized crank pulley, AND underdriven/oversized accessory pulleys? As in - for same cumulative underdriving effect, but with use of standard length belt?

[firekat]

I am going the FI direction. I also was considering weight reduction, mostly to keep the original balance of the car. My first thoughts were of course the battery, either going lightweight and/or relocating. I didn't get a chance to check weights but thought about the hood - carbon vs stock. I would want the carbon painted to match as I am not a ricer.

I was thinking of the Fluidampr but quite honestly did not see in the testing documentation a marked change, mostly it was different, with no gross changes in vibration from stock. My manner of thinking is changing rotational weight is potential vibration nightmare - and changes to drivability for a DD. Commentary by those with direct experience to a Fluidampr would be welcomed

A couple of other options could be lightweight starter/alternator? Do they even exist for this car?

In any case I don't think that I could reduce the weight enough to balance out the installation of FI.

I'll just see how much the installation changes the character, if at all, before I do anything.

Spare tire removal? After having lived with run-flat tires on a Mini, no way would I ever do that again. Sure you could Slime it, but take this into consideration; the current state of roads here in the States are getting so bad that when you do get tire damage, a can of Slime isn't going to fix it. Remember also that with the low profile tires you run on this car your more apt to get catastrophic tire failure than just a nail.

I have one other weight reduction program that I have always been working on. Eat less, exercise more.

[86TOYO2k17]

Originally Posted by churchx

86TOYO2k17: it seems to me that also that it might be safe at track to underdrive generator, as after all, for track prep one can precharge battery, and will drive at much higher rpms then when daily driving. And possibly with AC/music off.
Water pump .. but what if one turns up fans in tune to cool coolant more to somewhat compensate slower pumping speed? And if there is oil cooler installed?
There is possibility of also having much redundancy/extra in standard setup of standard car, designed in by manufacturer that may have wished much higher safety margin then minimally necessary. Manufacturer also may have chosen parts from it's part bin of maybe ones optimally fit for other cars, to save on R&D and manufacturing.
But again, i don't have any real data, hence why i asked, how much power is used up in turning generator, how much for A/C, for water pump, so thanks for posting that. Would like to know in addition to that what is considered to be safe in underdriving. Aand, then again i'm not considering even in future do overdriven/underdriving mods .. it just seems interesting topic to hear more about for one wishing to learn more about cars . Prefering to have that (even though redundant) safety margin in, even more so as mentioned gains seem too small to bother.
EDIT
btw, what do you think of underdriving/undersized crank pulley, AND underdriven/oversized accessory pulleys? As in - for same cumulative underdriving effect, but with use of standard length belt?

I am pretty sure most car manufacturers over engineer things like alt / water pump which is why underdriving 15% shouldn’t cause any negative efffects. I think on a stock car running everything at once requires 100-110amps? Which is right where you would be at if you where underdriving it. Ppl can add crazy sound systems and headunits and still run on stock. I wouldn’t stack oversized accessory pulleys with undersized crank unless It was a complete set. 15% underdriven seems the max You would want.

But Personally I’m not a fan of swapping stock crank pulley unless it’s with a better dampener. The ati one is 10% underdriven but I’ve read it’s not well
Built and requires maintainance. That’s y I would just stick to stock or upgrade to fluidampr. Testing shows it’s much better at dampening especially in higher rpms. Also looking at mustang/s2000/vw forums everyone praises fluidampr and there is more testing data on those forums showing the benefits.

[SuperTom]

Originally Posted by 86TOYO2k17

This is from another thread.

“std crank pulley is 143 OD, alt pulley is 57.5 and water pump is 132

alternator is 130Amp @ 14v = 4.4Hp to turn assuming 55% efficent and due to the pulley ratio its running @ 2.5 x crank speed

so adding 10mm ( Fensport pulley) reduces the ratio to 2.12 so 15% slower = 3.75 Hp to turn so + 0.65hp gain

Water pump std ratio is 1.08 with fensport pulley is 0.94 and water pumps typically take 7bhp to turn so again about 15% slower so 6 bhp to turn so 1 bph gain so in total, you should get about 1.6bhp gain”

Now at first I didn’t like the idea of underdriving the water pump but apparently alot of guys on the uk forums have been doing it with no problems and fensport claims it has no negative effect on engine temps. So now I’m thinking of just getting both and using new belt. Can argue the effects of lightweight pulleys. But oversized/underdriven pulleys do give some gains.

Im all about tweaking every ounce of power out of these things but It still seems like a lot of work for 1.6 hp