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audisnapr
09-15-2004, 11:38 AM
How much lag does most everyone else have? Not sure how to measure lag, but my car has always felt like it has a lot of lag, especially in the low RPM's (which I know is somewhat normal for these cars).

An example would be: sitting in traffic, your lane is moving super slow because someone ahead of you is double parked or doing something stupid. The lane next to you is wide open, but there is a car coming down that lane from behind. You have enough time to get over and pin it, but with the lag, you know in the back of your brain that unless you pop the clutch at higher RPM's you are really gonna cause that other car to slow down or even hit you.

Is there anyway to decrease the amount of lag in these cars? I'm running a GIAC chip and Evo DV.

Once the boost builds up at higher RPM's, the response is awesome. But how do you get more at lower RPM's?

A4-disiac
09-15-2004, 11:58 AM
I'm not too sure but I think a boost controller helps with that. I'm sure soneone with more expertise will chime in soon.

Daft
09-15-2004, 12:11 PM
A boost controller would be the wrong way to counter turbo lag.

Turbo lag occurs when a turbo and it's plumbing are semi-restrictive and the time needed to build boost increases.

Our ECU's are designed to carry a boost map and supply a load signal to the N75 which handles boost regulation via the turbo's wastegate. This is a well designed system and it is far more intuitive than a manual boost controller or even an electronic boost controller could be.

Since the N75 handles wastegate control, changes to the load signal change the wastegate position. The ECU supplies the signal and therefore, it can change boost pressures at any point to ward off detonation or pre-ignition and protect the motor. The knock sensor tells the ECU when it detects knock and the ECU tells the ICM to retard timing and tells the N75 to open the wastegate until the knock is gone.

Manual boost controllers are a difficult tool to tune a car with. They are linear in boost application and you must be very careful in how you change boost levels otherwise you can detonate a very large A/F mixture and in some cases damage various engine internals.

The best ways to correct turbo lag are to ensure that all vacuum lines are healthy and sealed at their connections, check IC pipes for tears and pinholes that would create boost leaks and make sure that all IC piping is a uniform size from the turbo's outlet to the intake manifold.

JMG
09-15-2004, 12:27 PM
Driving a turboed car is a little different from a NA. You can't expect the same reactions. So use a lower gear or learn where to bring your RPMs for a quick launch without glazing your clutch.

Hassmeister
09-15-2004, 05:34 PM
Turbo vs Normally Aspirated engine is totally diiferent.
When I drive the Turbo I have to keep in mind where I need to keep the RPM's, where as my '83 GTI is go NOW no matter where the RPM's are. It's the nature of the beast. Always be aware.

RedRocket
09-15-2004, 07:23 PM
Have you ever experimented with launching the car yet? I found in a turbo car you need to get that turbo spooling up. Usually you can move the car quicker but giving the engine a couple shots of gas to spool up the turbo, then as the rpms are falling....do the engage. Of course this is all depandant on if your Manual (the best thing invented by man [:D] )


Maybe this is useless info but I figured it took me a while to learn that myself so why not share.

Zodiak
09-15-2004, 07:28 PM
Originally posted by audisnapr

An example would be: sitting in traffic, your lane is moving super slow because someone ahead of you is double parked or doing something stupid. The lane next to you is wide open, but there is a car coming down that lane from behind. You have enough time to get over and pin it, but with the lag, you know in the back of your brain that unless you pop the clutch at higher RPM's you are really gonna cause that other car to slow down or even hit you.


In this situation cruise in the lowest possible gear (usually 1st around 4krpm, maybe second if traffic is moving fast enough, but at that speed it's a lot more spread out anyway) so when you punch it, the car just chirps up and goes.

skene
09-15-2004, 07:31 PM
^ what he said.

Definately learn how to get your RPMs up for situations where you need to get that instantaneous boost.

audisnapr
09-15-2004, 07:36 PM
thanks guys... I appreciate all the feedback and driving lessons [;)]

I think my question was answered earlier on. I was just wondering if there were any additional mods that might help take care of the fundamental problem of turbo lag.

I've been driving this thing for over 5 years now so I've figured out how to compensate for most of it's intricacies. The car never seems to disappoint.

HotSauce
09-15-2004, 08:15 PM
What RPMs are you getting the lag at? Do you have a boost guage?

skene
09-15-2004, 08:19 PM
nothing that will take away lag. unless you wanna go up in displacement on the engine...

2.0 perhaps?

audisnapr
09-15-2004, 08:28 PM
Originally posted by HotSauce
What RPMs are you getting the lag at? Do you have a boost guage?

the lag is most noticeable in first gear, from 1000-3000 rpm. For the most part, it really only affects me when I have ppl in the car, especially clients, where I'm not trying to pin it off the line. If I try to be "moderate/considerate" driver and not whip their heads back into the seat, I have to really bring the car up to speed slowly, starting at much lower rpms. But as many of you know, if you do that, the cars really shows its lag until it gets to about 3k, then all of a sudden, the turbo spools and you have to quickly let of the gas or everyone will feel like you decided to be speed-racer.

uh... no, not ready to undertake that kind of mod. I still can't decide on which bumper I want to get. Besides, I just got my chip. I haven't even got a chance to see what it can do. My first opportunity won't be until Oct. 2 at Pocono [:D]

Hassmeister
09-15-2004, 08:43 PM
Wow, sorry to hear that. My bottom-end to redline is shit and get. I find a slight bit of lack of response in 5th on the highway, but it's better than when it was stock. It weird... I tried my current setup (K04, FMIC, GIAC K04 chip) with a .08 bar chip and my response was better on the highway(snapier) - weird, can't put my finger on it.[rolleyes]