Flite

Do any of you have a picture of a dyno plot with a car that has a slipping clutch? Something doesn't look right on the VW boards and I'm trying to prove a point. Wheel spin will work too.

Fabrik8

Depending on how much it's slipping, it may be impossible to spot. If it's slipping because of overloading, it can look like peaky oscillations because it shudders when the engine power changes and the friction plate heat changes, but if it's just worn than the slip might now show up on the graph at all.
The answer is that it's usually hard to tell unless you already know the clutch is slipping and can correlate the dyno graph to that.
Tire slip is usually a little more straightforward to spot and usually makes the graph jumpy as the tires slip and grip as the suspension and sidewalls load and unload.. I haven't seen a graph like that in a while, most poeple don't save them because they're useless to get any info from.

Flite

This is my issue. I have pretty much the same car as what made this dyno plot. I have since changed a bunch of stuff (Bigger injectors, no more FPR, and stand alone) but when I had the car with a similar setup to this it drove VERY similar to what this dyno is showing. What actually happened is that the car would build boost and right around 3500-4000rpms the stock ECU would detect a too rapid torque rise and pull MASSIVE amounts of timing and close the drive by wire throttle momentarily and then it would clear up and pull hard to redline.

Supposedly the car in this dyno plot has a new ECU program and is running bigger injectors without an FPR and the company (EIPtuning) is claiming that the power band is 100% smooth. I got the owner of the car with this new setup to go dyno his car and this is what he came back with. EIP is claiming that the dip in the middle of the powerband is clutch slip or tire spin (dynapack tire spin???). Anyway, this is the dyno plot. It doesn't look anything like clutch slip to me. The peak up at the top of the powerband doesm but not the massive dip at 4000rpms.

Corey

haha. I was reading that thread. Rich is a funny dude.

Flite

Yeah, he's actually struck a nerve now. I'm so over his salesman shit and his half ass attempts to convince people he's a "tuner". It is now my mission to get the real truth out there and stop anybody else from making the same mistakes I did. EIP is truely a worthless company. I should have listened to all those people who told me not to buy EIP stuff.

regardless, my car is a beast now. You should buy it so I can buy a Corvette or Supra.

TPJ

Wow, I'd be kinda pissed if I just randomly lost 60whp like that.

Corey

How much? I need to sell my Miata. Sell that sucker for me.

EDIT: EIP is worthless except the fact that they have decent hardware. I've heard problems of ill-fitting piping, but other than that, no complaints (hardware wise).

Fabrik8

Clutch slip is bullshit. If the clutch was slipping at a certain torque, it would plateau at the same point as the torque rose back up. There is no indication that that is happening at all. I'm guessing the ECU is cutting power when it senses an overboost condition or something along those lines, like you're saying. I've heard some interesting things about VW ECUs trying to regulate boost in wierd ways once the engine has some mods to it, so this is probably a reflection of that. Modern ECUs kinda suck because they try to do fault correction every time they see something the least bit different from stock.

It would be nice to see some sensor data, I'd like to see the throttle position and manifold pressure during that dip.
The second peak is a little stranger, it looks like the ECU is doing some boost control, the turbo is probably running out of flow around that area. They have a crazy smoothing factor on that graph, it's probably hiding some interesting info.

Is it a Dynapack? Tire slip really would be fun to see then..

Corey

If that is a chart from EIP's dyno then it is not a dynapack.

HighPSI TSi Guy

RPM and mph. compare them.