Launching the car...

1644 Views 17 Replies 11 Participants Last post by Surferjer, Nov 9, 2004

xclusivecar

Discussion Starter · Nov 7, 2004

Having always owned Vettes and Z-28's, launching the car was never a problem. I'm not talking all out drag racing here, just quick exits from lights and such. Now that I've got a REAL sports car in the garage and having one with such a massive rev band, I can't seem to get used to balancing the rev's with the clutch and leaving the stop with a little kick in the pants. I understand the lack of torque in the mid range compared to those other cars. I either bog or leave the light like I'm driving Grampa's Caddy! Question--when wanting a little rush what technique are you using? Rev range, slip clutch, drop clutch, whatever?

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MattG

· #2 · Nov 7, 2004

I've only done one moderate launch, that was around 4k with a very brief clutch slip/dump. It was enough of a kick to cause my cell phone, which had been residing in the storage pocked under the light switches, to fly out of the pocket and land behind the seat.

Randy Chase

· #3 · Nov 7, 2004

Man, I can't put anything on the shelves without having them fly out, even on a trip to the grocery store.

Do not slip the clutch in this car. It only causes the clutch to burn.

JonOrangeElise

· #4 · Nov 8, 2004

Randy Chase said:
Man, I can't put anything on the shelves without having them fly out, even on a trip to the grocery store.

Do not slip the clutch in this car. It only causes the clutch to burn.

Please define "slip" versus "dump."

Or... Another way to say this: Don't we all slip the clutch a bit to foster a smooth, civilized launch?

Randy Chase

· #5 · Nov 8, 2004

I normally slip a bit, but I am trying to learn to not slip at all. At least on my car, any slipping of the clutch rewards me with a burning clutch smell. At higher rpms, it is even worse.

JonOrangeElise

· #6 · Nov 8, 2004

I felt the clutch was rather light and insubstantial during my test drives... Now, I'm assuming this is the same clutch package that Toyota uses, no? Is the clutch the weak link in the Celica as well?

eliseowner2b

· #7 · Nov 8, 2004

I've found that a good blip of the throttle is a nice way to start the car moving quickly. I haven't paid attention to the rpm's but I'd guess the tach is near 3500-4000 rpms when I let the clutch out with normal speed. Then you want to give it 1/2 throttle and increase it to full pretty quickly. This works for me and I haven't noticed the clutch slipping. Of course, if you want the ultimate launch, you really want to get the rev's to around 7,000 rpms when you let out the clutch. I did this once with the stock wheels/tires and they did spin but hooked up nicely. The A048s grip a lot more so the clutch will probably be the part to take the abuse. Either way, I'd find a happy medium so your car doesn't get abused.

CAErven

· #8 · Nov 8, 2004

I asked CrashTestDummy last Sunday at an AutoX in Louisville what RPM he launched at - he said he did it by feel but would look next run. He told me right at 5,000 RPM and I assume with not much slip. Not saying this has anything to do with street driving but it may give you info for quick launches from lights. The tires did spin a bit but not a lot and a little smoke and nice squeeling for a second - didn't see any tire hop - looked very smooth. I don't know squat about road or drag racing so take this info with a grain of salt - maybe ask C.T.D. for a "professional" opinion.

xclusivecar

Discussion Starter · #9 · Nov 8, 2004

Now that my car is fully "broken in" by lotus standards I am trying to have as much fun as possible with the car. My wife comments that it sounds as if were really flying due to the noise the engine makes behind her head and the rpm's you must get it up to to keep the thing moving...then she looks at the spedo and it's only showing 30 MPH! The car sounds as if your really moving when you really aren't! I think i'm still babying the car on launch and will try to work up the nerve to get on it a little more...I just keep thinking it's gonna break!

evomind

· #10 · Nov 8, 2004

ok, well here goes....
ive logged a lot of miles on the demo car, so im fairly familiar with how this car reacts to launches....in short, it doesent like hard launches very much....its the clutch.
when people talk about slipping the clutch, theyre talking about a launch technique where u use the clutch and throttle to modulate power to the wheels. for instance, if u were drag racing, if ur technique was to slip the clutch it would go something like this....
rev the car to whereever its powerband is, in this case, about 6200rpm...let the clutch out a bit and give it enough gas while maintaining at least 6200rpms...if this motor dips below 6200 rpm, u lose a lot of power...u dont want that...if the tires start to come loose, push the clutch in just a bit to ease off power...dont lift off the gas...when ur moving, then let the clutch out all the way and floor it..be ready to shift..i could go into more detail, but thats the short version. as randy has pointed out, this clutch burns up using that technique..its too bad cause that would be my preference for this car...(usually with small 4 bangers and high rev engines this would be my technique in rear wheel drive cars). get a more suitable high performance clutch and this car will allow u to launch a lot harder....
the other technique as pointed out previously, is the clutch drop..
thats basically "dumping the clutch." thats where u rev it to the point where the motor makes power and after dumping the clutch the car will shoot forward...dump the clutch and floor it...this procedure has it downsides....harder on the drivetrain and u cant control wheelspin as easily.
with the stock clutch u are pretty much forced to use the clutch drop technique....i had an issue with bogging just after launch with this technique but i didnt have much time to experiment with it.....it takes some practice to launch a car hard with minimal wheelspin.....
keep trying it at different launch points, but its gonna be somewhere between 6500-8000rpms....

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pinmagic

· #11 · Nov 8, 2004

evomind said:
keep trying it at different launch points, but its gonna be somewhere between 6500-8000rpms....

Not suggested for people who live further than walking distance from their repair shop!

Thanks for the info -- I wasn't familiar with the diff between those 2 terms.

evomind

· #12 · Nov 8, 2004

actually im not really worried about anything breaking....ill probably replace the clutch cause im not too impressed with the stocker, but im pretty confident the drive train is up to the task.
the only thing im worried about are the half shafts....i dont know how strong they are etc...

Randy Chase

· #13 · Nov 8, 2004

The one small positive of a weak clutch is you have less chance of anything else breaking. It becomes the sacrifical point.

However, an 8000rpm launch and it is not my Hoosiers that were spinning... kinda sucked.

In competition (ProSolo), I do expect we will be launching at over 7000 rpms. And then replacing the clutches. Kinda like the S2000 drivers.

P.S. If anyone is doing a clutch dump on less than a grippy surface, be careful about hop. If the back end hops a lot, you can cause damage to mounts and such. Quickly back off the gas and let it hook up, and next time use less rpms. More grip = more rpms. In the rain for example, anything above 3000rpm might be too much.

evomind

· #14 · Nov 8, 2004

hmmm...not sure if the elise can keep those hoosiers spinning.

randys right about the clutch, its the weak link and they may have wanted it that way cause the clutch is fairly inexpensive to replace....
and if u get wheel hop back off the gas or put the clutch in immediately....u can probably drive home if u break a mount, snap a halfshaft and ur done. halfshafts have a tendancy to break when ur wheelhopping.
the few launches ive had i didnt experience any wheelhop....

Allan Gibbs

· #15 · Nov 8, 2004

How much is a replacement clutch and how long is the labor to have it install. I have a feeling it's not going to be a do-it-yourselfer.

Surferjer

· #16 · Nov 8, 2004

At autoXs and as needed on the highway, I launch at 4500-5000. Minimal wheel spin, and a nice quick acceleration. In normal driving I ease out like any other car-I try to only abuse when necessary.

LotusLust

· #17 · Nov 9, 2004

ah, but jer, isn't it all about how you define "necessary"!?

Surferjer

· #18 · Nov 9, 2004

If I post my definition, the forum police will get me!

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