Corolla updates

It takes a bit of driving to get used to it. Looking at the top graph we can see that for 30% throttle the engine is making half power. In the modified throttle the engine is only making 20-25% power. In initial tip in, there's less going on with the power, so you have to drive with your foot planted a bit more.

thats some interesting stuff

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I be sorry as a muthafucka I did, still sorry I did n' hustled ta peep what tha fuck I holla'd a lil' bit better, or at least try to.

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Robert Culbertson
We do something very similar on our formula car, but with throttle position vs torque. We have a severely progressive throttle linkage set up. Currently we have decent gaps from 0-70%, but above that it gets a little packed. This year we are working on a pedal linkage to compliment the TB linkage as well. I'll see if I can find the before and after graphs for you.

So, I looked a little more closely at the graphs today...
So they old setup looked like at 50% throttle position you were pretty much near 100% torque whereas it's way lower on the new setup.
What's the difference? Is the butterfly basically at full efficiency with the old setup? By severely progressive do you mean that, for example, say you have 3 inches of pedal travel, the first inch opens the throttle 70%, the next inch opens it to 95% and the last inch opens it to 100%?

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Grant Hughes

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NoCoast

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Robert Culbertson
We do something very similar on our formula car, but with throttle position vs torque. We have a severely progressive throttle linkage set up. Currently we have decent gaps from 0-70%, but above that it gets a little packed. This year we are working on a pedal linkage to compliment the TB linkage as well. I'll see if I can find the before and after graphs for you.

So, I looked a little more closely at the graphs today...
So they old setup looked like at 50% throttle position you were pretty much near 100% torque whereas it's way lower on the new setup.
What's the difference? Is the butterfly basically at full efficiency with the old setup? By severely progressive do you mean that, for example, say you have 3 inches of pedal travel, the first inch opens the throttle 70%, the next inch opens it to 95% and the last inch opens it to 100%?

I will try and illustrate with a couple pictures. I am doing it electronically, Robert is doing it mechanically but we are both doing the same thing - making the power output of the engine more linear with the movement of the throttle pedal.

Here is how my car was setup for the dyno readings above:



Ratio is 1:1, pedal position being the top row and throttle blade position being the bottom row. On my car right now it basically achieves full power at 60% throttle opening (save for a tiny bit at high rpm). All it really means is above 60% opening the throttle is no longer the restriction in making more power, something else is. People often just throw bigger throttle bodies on because bigger is better right? Now I fully expect mine to change because right now my exhaust is smashed down, so once I fix that the power should come up, airflow will increase through the system and I will probably need more than 60% throttle opening to make full power (hopefully).

And here is a possible curve to more closely match the power output percentage to the throttle pedal movement. If you look at most factory throttles, the cable pulley is not round. It will have a shape to it that is giving the same effect I am showing here. I have not tested this one, but may this winter for fun. I have a few things I want to try out before next season.

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

Yep, that's pretty much it! With a mechanical throttle you can vary the leverage ratio in two locations: the pedal, or the throttle itself. We use both. The throttle body is set up to have a leverage arm that get's shorter as more cable is pulled (the wheel is round, just mounted about 80% off center). This allows the throttle to rapidly open as you get further into pedal travel.

Unlike John, our throttle body/restrictor is the major restriction in the intake system. Per rules we have to run a 20mm restrictor. This is why we slow down the initial tip in. I'm sure on a street car this problem isn't nearly as bad.

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NoCoast

So, I looked a little more closely at the graphs today...
So they old setup looked like at 50% throttle position you were pretty much near 100% torque whereas it's way lower on the new setup.
What's the difference? Is the butterfly basically at full efficiency with the old setup? By severely progressive do you mean that, for example, say you have 3 inches of pedal travel, the first inch opens the throttle 70%, the next inch opens it to 95% and the last inch opens it to 100%?

Ok, time to do some winter updates to the car, the primary one (other than sorting out the front suspension) is to put the Corolla on a much needed diet.

I know Lexan is a somewhat generic brand thrown around, but for side and rear windows what material does everyone recommend? And any place better than another to get it or have it cut to shape (or just DIY)? And is it a stupid mod (just leave the glass and eat less this winter) or something with minimal ill effects?

Not planning to change the structure of the car at all, just picking off some of the excess fat that doesn't really affect reliability/strength.

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

The problem with lexan is it starts to look like crap in short order and racing in the dirt doesn't help matters at all. Being that you've got a RWD car, I'd suggest leaving the front driver and passenger windows glass and doing lexan on the rear stuff.

Also, something to consider is how much the lexan will actually save you. An Evo (and STi maybe?) use thinner glass from the factory, so those cars won't save as much weight as say a BMW with acoustic glass.

Dave

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DaveK
The problem with lexan is it starts to look like crap in short order and racing in the dirt doesn't help matters at all. Being that you've got a RWD car, I'd suggest leaving the front driver and passenger windows glass and doing lexan on the rear stuff.

Also, something to consider is how much the lexan will actually save you. An Evo (and STi maybe?) use thinner glass from the factory, so those cars won't save as much weight as say a BMW with acoustic glass.

Dave

Yeah the actual weight of the glass is a big question mark for me. I have "heard" it is pretty heavy but I plan to pull it out and weight it first. At most I will do the rear side windows and the hatch glass.

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

The rear side windows hardly weigh anything. The hatch glass is probably pretty heavy though. That's just a guess based on getting hit in the head by it though lol

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Rallyst165
The rear side windows hardly weigh anything. The hatch glass is probably pretty heavy though. That's just a guess based on getting hit in the head by it though lol

LOL I am actually just trying to avoid buying new hatch struts for it. Make it lighter, maybe it will stay up! HAHAHA

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com

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John Reed
Yeah the actual weight of the glass is a big question mark for me. I have "heard" it is pretty heavy but I plan to pull it out and weight it first. At most I will do the rear side windows and the hatch glass.

On my GTX, I swapped out to lexan on all 5 back windows and ran it that way for a season of hillclimbs. It did save weight for sure, especially the hatch. I was able to remove one of the hatch struts and the back still fired open fast enough when you pulled the release latch.

When I decided to run Pikes Peak, they've got a clause in the rules that states the car must look presentable...so I put the glass back in and got a $200 maaco paint job.

Dave

I will add that I am NOT a fan of Lexan in the front doors. I keep a glass breaker at hand to the driver or co-driver, and would really like to be able to get out of a car when the doors don't open.

My guess would be 10lb savings max if you did the hatch and rear side glass.

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phlat65
I will add that I am NOT a fan of Lexan in the front doors. I keep a glass breaker at hand to the driver or co-driver, and would really like to be able to get out of a car when the doors don't open.

My guess would be 10lb savings max if you did the hatch and rear side glass.

There are ways of doing door windows in Lexan and making them quickly and easily removable. But yeah, there should be plenty of lower hanging fruit when it comes to removing weight before you get to the little you will save by Lexan windows.

Thanks for the input guys. I have decided to just get as much weight out of the stock hatch as I can (keep OEM metal, lexan window) and the rest of the windows will stay how they are now (which is stock glass).

Took the car out this weekend for a non-timed tarmac rallysprint aka drift event. The car is not even remotely setup good for tarmac right now (old nasty stock front struts since John has my good stuff for repair) and the JVL stuff on the back still. Lots of body roll but it was raining so that helped and plenty of fun was had. Learned a few things about the car I want to change, that should be good for rally.

I would rank the event right there with a rallycross in terms of cost versus seat time/fun. Gave a bunch of rides, everyone loved the rally car, and drove it there and home. Can't beat a day of sliding the car around with minimal expense. Not anywhere close to the fun of stage rally though!! This is going to be a long winter......

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John Reed
John Reed Racing
www.johnreedracing.com
johnreedracing@gmail.com



Edited 1 time(s). Last edit at 12/17/2012 09:48AM by John Reed.

I think I've got a quarter window laying around here somewhere, I can weigh it for you if I find it. I only had one rear window, though, and its back in. I never weighed it. (I have lexan side windows, not rear)

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