The worst mod you ever did to your twin?

[Yoshoobaroo]

Originally Posted by funwheeldrive

If anything this car needs to lose weight. 2600lbs in this car would be great.

175lbs is a pretty tall order seeing that the car is already built light. Racecar spec is one thing, but as a daily that might be tough. Unless someone already has haha.

-Josh

[Tcoat]

Originally Posted by Yoshoobaroo

175lbs is a pretty tall order seeing that the car is already built light. Racecar spec is one thing, but as a daily that might be tough. Unless someone already has haha.

-Josh

http://www.ft86club.com/forums/showthread.php?t=42284

[gramicci101]

Originally Posted by Tcoat

http://www.ft86club.com/forums/showthread.php?t=42284

Exactly what I was thinking of.

[RedFR-s]

My least favourite and also my favourite mod was going FI.

Least because it's been nearly 2 years of trouble shooting and adding supporting mods that were unplanned to get her running well and reliably. (My fault should of done more research, bit of an impulse buy).

Favourite because every time I go for a drive and hit boost I get that stupid grin I used to get when she was brand new. I love the way she is now and everyone that has driven her agrees that she has really come to life with the turbo.

[funwheeldrive]

Originally Posted by Yoshoobaroo

175lbs is a pretty tall order seeing that the car is already built light. Racecar spec is one thing, but as a daily that might be tough. Unless someone already has haha.

-Josh

Light 16" wheels, No AC, no radio, lightweight battery, lighter glass, no spare, and lightweight buckets from the factory would be cool with me. It would be expensive though.

[Kevstra]

Originally Posted by nikitopo

This was puzzling me a bit for some time. There is a reputable company in Japan saying that a lightweight crank pulley kit works and there are users saying the same like you. That it is a complete waste of money.

I tried to model the weight reduction of a LWP and calculate the gains from the moment of inertia. Fact is that the gains are very small to be noticable. However, the claims of the Japanese company are not wrong.

Here is some conclusions:
- You need to change the pulleys with a stiff material. Original pulleys are made from cast iron and they deform slightly with rotation. You can imagine material deformation as an additional parameter in the moment of inertia law. Only the OEM crank pulley might deform much more, because of the included rubber structure. Companies are using for the LWP the cheap 6061 aluminum with a yield strength of 240 MPa. This material seems to not provide enough stiffness. There is a much harder aluminum with a yield strength of 500 MPa, but it is very expensive.
- You need a kit of at least 3 pulleys (crank, alternator, water) and not just a crank pulley. Companies are providing usually only the crank pulley because it is cheaper and easier to install.
- You need to under-drive the system. Usually, this can be done with under-driving the alternator.


My findings were that each of the above can provide small gains and all of them in combination could provide a sufficient gain which is noticeable. Fact is that very few manufacturers provide such solution.

I think there should be a minor correction on these points... and I hope this is close enough to the topic of the thread it's not considered derailing.

First, strength is not the same as stiffness. Cast iron is actually stiffer than aluminum with a modulus of elasticity, E, of ~100-125 GPa compared to aluminum's ~77 GPa. Steel is ~200 GPa for comparison.

Second, the moment of inertia (which is the property of interest for LWPs) is not effected by stiffness but by mass and physical dimensions. We're interested in the moment of inertia because it's the property that describes how quickly something will spin-up (angular acceleration) for a given torque. A smaller moment of inertia gives you a faster spin-up.

LWPs work on reducing the moment of inertia of the driveline.

When you're in first gear, the engine has a large leverage advantage on the mass of the whole car and so the moment of inertia of the driveline plays a greater role in determining how quickly everything accelerates. The role that the driveline's moment of inertia has on the system as a whole quickly diminishes in the higher gears, where the car's mass governs the equations.

Reducing the moment of inertia of the pulley certainly allows the whole system to accelerate more quickly, but it's a question of magnitude. I don't doubt there's a small but measurable effect in first gear, but in higher gears I suspect that any butt-dyno evidence is purely placebo.

Finally, the rubber in the pulley is what makes it a harmonic dampener. The role of that element is beyond the scope of this post, but engineers at Toyota would describe something about engine longevity and harmonic vibrations in the crankshaft.

Unless you're a drag racer, I'd argue that such a mod is probably a waste of time and money.

Cheers!

[DarkSunrise]

Originally Posted by nikitopo

You need some very expensive and quality aftermarket parts to have an actual difference. This is a well thought car. For example, I remember some aftermarket vendors changing the suspension to coilovers and the trials on a track were giving almost same or even worst times. Then they were trying to hide this by changing simultaneously the tires size ...

FI is a good option and for sure it makes a difference, but the engine compression ratio is a bit high for my tastes.

Yeah it's hard to find reliable reviews/data on aftermarket suspension. When I was deciding what to buy, I looked around and managed to find some sources I trust. In case you or anyone else is looking, take a look at these.

Here's a comparison where they tested a stock FR-S, then added KW V3 suspension, then added Hankook RS3 tires. Laps were done at TMP by Dave Pratte (former Canadian Touring Car Series winner).

Stock baseline: 1:26.875 (max lat G 1.12)
With KW V3: 1:25.377 (max lat G: 1.15)
With RS3: 1:22.607 (max lat G: 1.34)

http://www.superstreetonline.com/fea...ing-challenge/

And here's a write-up on RCE T2's (resprung/revalved KW V3) by Randy Pobst (pro driver). No data in this one, but Randy's got so much driving/racing experience that I trust his feedback.

http://www.sportscarmag-digital.com/...015?pg=22#pg22

[nikitopo]

Originally Posted by Kevstra

Unless you're a drag racer, I'd argue that such a mod is probably a waste of time and money.

Honda was using an OEM lightweight crank pulley in their Civic Type R car for some Enduro races in Japan. I don't think these guys were ignorant and when Honda speaks all the others ... However, Honda's pulley was made by Zinc Plated Steel.


I agree with you, most pulleys don't provide much. Basically a placebo effect in 2nd-6th gear. If you go with the big guys, then it is another story. But you have to pay for the materials and the know-how.

[Yoshoobaroo]

Originally Posted by funwheeldrive

Light 16" wheels, No AC, no radio, lightweight battery, lighter glass, no spare, and lightweight buckets from the factory would be cool with me. It would be expensive though.

No AC
That's a big nono for a daily
No radio
Same as above
Lightweight battery
Daily driver => it needs to start EVERY time
Lighter glass
Maybe there's some margin there, but I doubt it's much. I could be wrong.
No spare
Without runflats? Nahhhhh
Lightweight buckets
Stock seats weigh ~35lbs. That's not bad but you'll be hard pressed to find a comfortable seat for daily driving that weighs much less.

I'm not trying to be dismissive of your post, just pointing out that I'm looking at it as a car I need to drive for at least 2.5 hours a day.

Originally Posted by Yoshoobaroo

Racecar spec is one thing, but as a daily that might be tough.

[cjd]

Originally Posted by Yoshoobaroo

No AC
That's a big nono for a daily
No radio
Same as above
Lightweight battery
Daily driver => it needs to start EVERY time
Lighter glass
Maybe there's some margin there, but I doubt it's much. I could be wrong.
No spare
Without runflats? Nahhhhh
Lightweight buckets
Stock seats weigh ~35lbs. That's not bad but you'll be hard pressed to find a comfortable seat for daily driving that weighs much less.

I'm not trying to be dismissive of your post, just pointing out that I'm looking at it as a car I need to drive for at least 2.5 hours a day.

I'm with you on seats, though your weight is low; I like the added safety margin... people ignore stop signs on my street all the time - I had some guy going crazy gesturing and yelling at me today - he was behind the guy that blew a sign and made me stop short when I had the right of way because... he thought he also should get to go in front of me. Then again, he also didn't like me not driving through the old man shuffling across the street (and right in front of me...)

However... light-weight battery will start every day, even in winter, if you drive it every day. And while you may want a radio, you can reduce the weight by a few pounds with strategic component selection.

On the other hand, unless you're actually out driving where time counts, the weight is irrelevant. Keep your spare for the street. Take it out to race.

100lbs is pretty easy to lose for a track day (AP Sprint, LW battery, header and full exhaust, and of course ditch the spare.) Don't get heavy wheels... so many people cheap out and add weight in the worst possible place.

[Wise]

Originally Posted by ninedice

Worst mod I did was installing a cat-less header and down-pipe. Cold start ups woke the dead and it smelled like charcoal lighter fluid everywhere I went. After a month of trying to tune out the excessive noise and living with the smell I gave up and put the stock header back in.

For me catless headers are only really feasible if you plan to run stock catback or a model like the Q300 and keep the cat in your front pipe.

Any car with no cats and minimal or no muffler is going to make your neighbours hate you.

[Wise]

Originally Posted by SUB-FT86

I need to drive one most definitely because the guy I quoted said he didn't feel a thing. Now on this very forum I saw a lot of good praises for stage 1 OFT with filter and catback yet when I bought the OFT I felt 0 differences. It actually felt like I lost some power to a degree.

I felt zero difference at Stage 1 tune with intake and catback.

Car currently has UEL catless header and Stage 2 tune and the butt dyno does register a slight increase and more response in the midrange.

UEL, Catback, intake and stage 2 should produce around a 10-15% power bump over stock, I think that's about the minimum increase a regular person's butt dyno can pick up.

[Yoshoobaroo]

Originally Posted by Wise

-around a 10-15% power bump over stock, I think that's about the minimum increase a regular person's butt dyno can pick up.

I think you're right about that


-Josh

[nikitopo]

Originally Posted by funwheeldrive

If anything this car needs to lose weight. 2600lbs in this car would be great.

I would have loved a RS model offered here like they do in Japan.

Originally Posted by Yoshoobaroo

175lbs is a pretty tall order seeing that the car is already built light. Racecar spec is one thing, but as a daily that might be tough. Unless someone already has haha.

-Josh

Originally Posted by funwheeldrive

Light 16" wheels, No AC, no radio, lightweight battery, lighter glass, no spare, and lightweight buckets from the factory would be cool with me. It would be expensive though.

Originally Posted by Yoshoobaroo

No AC
That's a big nono for a daily
No radio
Same as above
Lightweight battery
Daily driver => it needs to start EVERY time
Lighter glass
Maybe there's some margin there, but I doubt it's much. I could be wrong.
No spare
Without runflats? Nahhhhh
Lightweight buckets
Stock seats weigh ~35lbs. That's not bad but you'll be hard pressed to find a comfortable seat for daily driving that weighs much less.

I'm not trying to be dismissive of your post, just pointing out that I'm looking at it as a car I need to drive for at least 2.5 hours a day.

My car weights 2620lbs and it is almost stock form. It was the last year (2015) that the bare bones version was sold here. Funwheeldrive is pretty close of how to achieve this weight. I don't have radio or A/C, but I don't care. Also limited sound deadening material, but again I don't care. It is not a daily driven car. My only modification was to change the battery to a lighter one, because the OEM one got dead quickly. For the spare tire, you don't really need it. You have a flat kit that helps to drive the car till a close garage.

I agree for the stock seats. They are not heavy. I could gain some weight (~20-25lbs) only if I replaced them with Recaro's carbon-fiber seats. Again an element that you can really improve this car, but only with high quality and expensive materials.