Random thoughts thread

[serialk11r]

Originally Posted by Dimman

The other CR raising options are decking the living shit out of the head (if we're talking about chasing 12+:1) but that can screw up the squish area and shape of the combustion chamber and possibly weaken the head. The other is filling the chamber with aluminum weld and (assuming you don't warp it) re profiling it.

Short version: 2ZZGE is already done and ready.

Screw the 2ZZ, it costs money. Machining...takes a lot of time. To remedy squish perhaps removing a tiny bit of material off the center of the piston would help place more air/fuel mix towards the center?

[Dimman]

Originally Posted by old greg

You make one change at a time and see if it makes the car faster or slower. That's all there is to it, whether you're in local autocrossing or Formula 1. Math, science, instrumentation/datalogging etc. can help you decide which parameter to change and which direction to change it in, experience can help you decide how much to change it by. But in the end you take a guess, you make a change, and you see what happens. If it's better change it some more, if it's worse change it back.

Start reading if you want to learn. Carroll Smith and Paul Haney are a good place to start. Just understand that the rabbit hole goes very, very deep.

How er... practical is that Paul Haney tire book? I ordered a tire book basically at random and it just arrived today and I started to flip through it. 'Tire and Vehicle Dynamics' by Hans Pacejka. Heard of it or read it? If you have you can pretty much guess that the most that I will understand from it is the damn title...

[Guff]

Originally Posted by M-17

No doubt, that makes total sense, but I'm not saying he's probably got nothing in his car. I wouldn't expect to see any high performance upgrades, just something simple.
It's weird that I actually don't like hood scoops on supras. I find that those ruin the whole look. I do like vents on supras though.

But keeping it simple and clean looking can never be looked frowned upon, unless the car is ugly to begin with.

I can live with the Euro Scoop because One, it's an OEM part, and Two, I believe it actually serves a purpose in cooling the engine.

And yes! Simple is beautiful!

[Dimman]

Originally Posted by serialk11r

Screw the 2ZZ, it costs money. Machining...takes a lot of time. To remedy squish perhaps removing a tiny bit of material off the center of the piston would help place more air/fuel mix towards the center?

1ZZs cost money too. Better get familiar with some CAD and FEA software so you don't have to buy another 1ZZ.

Flowbench is handy for measuring air capacity. But charge motion and combustion will pretty much need a dyno. Unless you have access to some fancy CFD/simulation stuff through your school?












Other note, I haven't been to the strippers yet this year! The hell is wrong with me?

[serialk11r]

Originally Posted by Dimman

1ZZs cost money too. Better get familiar with some CAD and FEA software so you don't have to buy another 1ZZ.

Flowbench is handy for measuring air capacity. But charge motion and combustion will pretty much need a dyno. Unless you have access to some fancy CFD/simulation stuff through your school?

Not really, I think the FSAE club has some CFD stuff but I wouldn't ever bother to use it lol.

Obviously any ghetto mod on a car would have to be conservative to avoid costing even more money when the engine blows. Maybe like, deck it to 11:1. Theoretically, that would probably get me like 2hp maximum but 2hp is 2hp :P Probably won't touch stock redline.

[Dimman]

Originally Posted by serialk11r

Not really, I think the FSAE club has some CFD stuff but I wouldn't ever bother to use it lol.

Obviously any ghetto mod on a car would have to be conservative to avoid costing even more money when the engine blows. Maybe like, deck it to 11:1. Theoretically, that would probably get me like 2hp maximum but 2hp is 2hp :P

Or start with aero mods? Undertray out of fiberglass, airdam and skirts?

[serialk11r]

Originally Posted by Dimman

Or start with aero mods? Undertray out of fiberglass, airdam and skirts?

Yes yes, that was already on my mind
The MR2 has a lot of space to improve on since it has a shitty softtop. BMW 6 series softtops have those little ears that stick out and reduce the vortices coming off the back, so that would be a good place to start, adding fins to the engine cover. With really creative metal bending it should be possible to make glue on parts, although drilling into the cover would be 10 times easier. Now I have no idea how to make this look aesthetically appealing but maybe that's something I can figure out when I actually buy the car

Undertray, skirts, certainly, but no airdam, with an undertray they do more harm than good. I kind of want to drill into the rear window piece and make a spoiler, but that seems like it would be very hard and quite irreversible heh.

Oh and of course, moving that stupid muffler up so it doesn't interfere with airflow and venting exhaust out the bumper into the wake.

[Dimman]

Originally Posted by serialk11r

Yes yes, that was already on my mind
The MR2 has a lot of space to improve on since it has a shitty softtop. BMW 6 series softtops have those little ears that stick out and reduce the vortices coming off the back, so that would be a good place to start, adding fins to the engine cover. With really creative metal bending it should be possible to make glue on parts, although drilling into the cover would be 10 times easier. Now I have no idea how to make this look aesthetically appealing but maybe that's something I can figure out when I actually buy the car

Undertray, skirts, certainly, but no airdam, with an undertray they do more harm than good. I kind of want to drill into the rear window piece and make a spoiler, but that seems like it would be very hard and quite irreversible heh.

Oh and of course, moving that stupid muffler up so it doesn't interfere with airflow and venting exhaust out the bumper into the wake.

Have you seen one of the S2k's after market hatdtops that gives it a smoother fastback style? I would like something like that on the MR-S. Sidenote, perusing my local craigslist they are going from $8k to $15k locally. Which is fucking absurd. Jdm 6 speed TT Mk4 Supras are ~$16k for fucksakes....

[serialk11r]

Originally Posted by Dimman

Have you seen one of the S2k's after market hatdtops that gives it a smoother fastback style? I would like something like that on the MR-S. Sidenote, perusing my local craigslist they are going from $8k to $15k locally. Which is fucking absurd. Jdm 6 speed TT Mk4 Supras are ~$16k for fucksakes....

Yea, I'm not actually that scared of trying to fabricate something that almost seals in everything, except there are 2 problems. One being that the soft top needs to be able to open (hard tops for MR2s go for like, what, 3000 bucks? T_T) just in case, the other being that the engine cover needs to be able to open without having to disassemble the whole roof. I think it wouldn't be too hard to fabricate a "fastback" that attaches to the engine cover, with a roofline extension going from the top of the soft top back, but the problem is the moment you want to open the engine, then the roof extension will pivot straight into the interior of the car, which is bad.

Hence, I'm thinking a roof extension mounted to the window itself, plus some "winglets"/"fins" to cut down trailing vortices. Not all that bad, because the mid engine design will let a small amount of air from the engine help fill in that "dead space" behind the window, though it's best if that air goes straight back to the bumper area. I believe the stock C_d is 0.32, which is amazing for a ragtop with just about the worst underbody ever.

Too scared to try and fabricate a full hardtop, I don't want to mess with trying to get it to seal.

[old greg]

Originally Posted by Dimman

How er... practical is that Paul Haney tire book?

It's a shit-ton more practical than Pacejka.

Seriously, buy it. Its one of my favorite books.

[Dimman]

Originally Posted by old greg

It's a shit-ton more practical than Pacejka.

Seriously, buy it. Its one of my favorite books.

This book has 'graphs' that seriously look like a 2 year old spent 10 minutes scribbling. Plus greek letters in the formulas that I've never even seen before.

Is there a way to generate a tire's effeciency curve from skidpad testing? All the weight transfer theory seems pretty useless without knowing a tire's load:grip relationship.

[ichitaka05]

In the mood to listen to Eric Clapton songs...

Random? Yes, that's why I posted here lmao

[old greg]

Originally Posted by Dimman

Is there a way to generate a tire's effeciency curve from skidpad testing? All the weight transfer theory seems pretty useless without knowing a tire's load:grip relationship.

You could get a pretty decent approximation from the datalogs of one or more strain gauges on each suspension member, steering position sensor, GPS and Z axis gyro (or 2 accelerometers). You'd need to do a lot of driving, and not on a skidpad, with varying amounts of ballast. And then you'd need to spend a lot of time sorting and analyzing the mountains of data. The pros just buy time at places like Calspan, or even just ask the tire manufacturer very nicely to share their data.

Even with tire data, theory is still pretty useless without a large time investment into modelling and simulation. And even then it isn't an exact science. If it was, race teams would just show up on Saturday with the car set up perfectly, run three laps to qualify, then roll their car into the garage and go out drinking. But theory is useful in that it can help you to understand what's happening, why and how to fix it.

[ichitaka05]

My friend's wedding is this weekend... what should I wear to the wedding? Violet shirt w black & violet stripe tie? Or maybe blue shirt w sky blue tie? Or go w Chinese style shirt?

A lot of choose from...