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.
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mke723 Mike Lindenfelser Junior Moderator Location: Minnesnowta Join Date: 10/17/2012 Age: Midlife Crisis Posts: 154 Rally Car: 1995 Impreza L |
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NoCoast Grant Hughes Professional Moderator Location: Whitefish, MT Join Date: 01/11/2006 Age: Midlife Crisis Posts: 6,818 Rally Car: BMW |
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%? Grant Hughes |
John Reed John Reed Senior Moderator Location: Portland, Oregon Join Date: 06/09/2012 Age: Midlife Crisis Posts: 176 Rally Car: Toyota AE86 |
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. 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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John Reed John Reed Senior Moderator Location: Portland, Oregon Join Date: 06/09/2012 Age: Midlife Crisis Posts: 176 Rally Car: Toyota AE86 |
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. John Reed John Reed Racing www.johnreedracing.com johnreedracing@gmail.com |
DaveK Dave Kern Mega Moderator Location: Centennial Join Date: 07/11/2008 Age: Midlife Crisis Posts: 1,085 Rally Car: Compact M3 & Evo IX |
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 |
John Reed John Reed Senior Moderator Location: Portland, Oregon Join Date: 06/09/2012 Age: Midlife Crisis Posts: 176 Rally Car: Toyota AE86 |
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. John Reed John Reed Racing www.johnreedracing.com johnreedracing@gmail.com |
Rallyst165 Joel Pacello Elite Moderator Location: Hillsboro, or Join Date: 04/02/2012 Age: Midlife Crisis Posts: 12 |
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John Reed John Reed Senior Moderator Location: Portland, Oregon Join Date: 06/09/2012 Age: Midlife Crisis Posts: 176 Rally Car: Toyota AE86 |
LOL I am actually just trying to avoid buying new hatch struts for it. Make it lighter, maybe it will stay up! HAHAHA John Reed John Reed Racing www.johnreedracing.com johnreedracing@gmail.com |
DaveK Dave Kern Mega Moderator Location: Centennial Join Date: 07/11/2008 Age: Midlife Crisis Posts: 1,085 Rally Car: Compact M3 & Evo IX |
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 |
phlat65 Sean Medcroft Mega Moderator Location: Edmonds, Washington Join Date: 02/12/2009 Age: Possibly Wise Posts: 1,802 Rally Car: Building a Merkur |
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. |
Doivi Clarkinen Banned Elite Moderator Location: the end of the universe Join Date: 02/12/2006 Age: Possibly Wise Posts: 1,432 Rally Car: 1980 Opel Ascona B |
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. |
John Reed John Reed Senior Moderator Location: Portland, Oregon Join Date: 06/09/2012 Age: Midlife Crisis Posts: 176 Rally Car: Toyota AE86 |
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...... 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. |
Dazed_Driver Banned Super Moderator Location: John and Skyes Magic Love liar Join Date: 08/24/2007 Posts: 2,154 |
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)
Welcome to the cult of JVL drink the koolaid or be banned. |