launch - clutch/turbo question...

[murph1379]

ok, I'm looking for an explaination of how the turbo decides when to spool and how the clutch works... I find that when I launch with the clutch about half in it seems to let the other half spool the turbo much faster, and allow me MUCH faster launch after a second or so of doing this. I'm wondering if I'm imagining it or if the engine is revving faster because I'm not completely on the clutch, creating more exhaust, and therefore more boost, and then when I let 'er rip, we're already up to full boost and going strong... That's what it seems like, but I'm not sure if the turbo only "accepts" exhaust for boost when the clutch is in, and if this is hard on the clutch, can someone explain this to me? I've done this while autocrossing, and people remark how much torque I must have in my car, and I'm wondering if this is a good technique for turbo cars, or if I'm headed for a busted transmission... any input?

Thanks in advance.

 

[girth]

The clutch has nothing to do with the turbo spooling up. And actually it's the opposite of what you're thinking -- the engine will rev faster with the clutch fully depressed vs 1/2 depressed. Basically from your description all you're doing is slipping the clutch and causing extra clutch wear. Your starts might seem a little faster because obviously with the clutch peddle 1/2 depressed, the clutch fully engages a little sooner since you're holding it "partially engaged" with the peddle 1/2 way down.

Not sure if that made sense but quit doing what you're doing unless you enjoy replacing your clutch prematurely.

 

[Ehawley]

The bigger issue tends to be wheel spin at launch. If you 'let er rip', you generally get a lot of wheel spin, which slows you down. If you feather the clutch (let it out gradually) you get two advantages: 1) You keep the tires right at the edge of losing grip, which is where you want to be 2) You keep your rpm's up which gets your turbo spooled faster. As stated above, this does increase clutch wear in the long run, but fast cost money

 

[jurgs01]

You need to get a better clutch if you want to do that. The stock clutch will not take it for long. That's why girls have the replace a clutch ever 30K miles Work your launching technique so the let off of the clutch is a smooth transition (not slow or stopping half-way), and launch at between 3 or 4K rpm depending on your traction and if you have motor mounts.

 

[t3ase]

You need to get a better clutch if you want to do that. The stock clutch will not take it for long. That's why girls have the replace a clutch ever 30K miles Work your launching technique so the let off of the clutch is a smooth transition (not slow or stopping half-way), and launch at between 3 or 4K rpm depending on your traction and if you have motor mounts.

I know of MANY girls that own 90% of this board in driving and racing. Careful about what you say, jokes or not.

 

[murph1379]

I know of MANY girls that own 90% of this board in driving and racing. Careful about what you say, jokes or not.

Agreed, this girl niki whips my butt every month in her ITR autocrossing. (you know, where driver skill means something)

Good to know about the clutch, so a smooth drop from 3k or so is better for it than holding it at around half until the motor is at like 4k and the turbo is screaming and then engaging?

And as I was thinking, the turbo spools whenever you have exhaust, so it doesn't depend on whether you have the clutch in. I'm just starting to learn heel-toe breaking, and it's helping a lot, I know it's used to keep the rpms high, wasn't sure if it helped with boost as well, sounds like it does.