1st time to the drag strip

[madman]

My club entered a car show today which happened to be at the drag strip so.......why not do both.

This was my first time ever running the 1/4 mile.

I was on 92 octane and around 20lbs of boost.

I know the car needs a better tune, something I've been strugling with, but I thought I would put it on the track and see where I'm at.

Aslo to mention, I know I have an exhasut leak somewhere, still searching.

The pics are of my first and last run, I made 5 passes.

The first time up I went right by the staging lights, not paying attention, watching the cars ahead and looking for their times. Went by it by 1 1/2 car lengths.

The second time I went past the guy, trying to hold us before staging, and went right up to the lights. didn't go beyond them though.

I guess I had to get the embarasing moments over first.

So the first two runs I didn't realy pay attention to my launch rpm's and went from just my normal feel of the car. My third time up I tried to watch where my rpm's where and ended up bogging down in first gear and ran a 14.2. Needless to say I work on the rpm consistancy another time. 4th and 5th runs went pretty well.

So anywasy here are my slips. Right lane. I was pretty happy with the times. Like I said I know my car has the potential for a lot better with my mods but since the tune isn't the best and being my first time out, 13.2's were good enough for me.

 

[andymoraitis]

There's a few things that stick out. On the good side, your 60' times are consistent and while there's more in there, they're fine. What I find strange is that your 1/8th mile times seem to be lower than they should be and that your MPH through the traps isn't very high for your setup. The one thing that kills top end power is lack of timing advance and I'm wondering if timing isn't being pulled due to knock and you're not aware of it.

I'd hook up a logger and see what you're getting for timing and also look at the airflow. With a good driver, 104 MPH traps are good enough for a 12.9 so it looks like the motor's going flat in the middle of the track which is around the time that you'd be hauling the mail in third gear and getting ready to hit fourth. Something in the tune is off there.

 

[madman]

Timing has definitely been an issue for me. I'm only getting 13 to 14 degrees of timing at redline.

My logs will not have any dips in the timing, just stays flat through out the curve. I have some long threads about this and just something I've been fighting for a while.

But you realy know you sh**.......you hit it right on the head.

Airflow....my AFC only shows around 1700hz, log 24-25lbs, but I think that is from the MAF-T lowering the number before the AFC sees it then the AFC lowers it so the ECU isn't seeing much at all.

As far as gears go, I am hitting 4th gear right at the end of the track....I don't know if that makes any difference or not....some guys kept asking me if I made it to 4th gear

 

[andymoraitis]

I think if you're timing and airflow are that low, that you're suffering from boost leaks which is lowering the airflow signal. I'd run a test just to be sure. From a technical standpoint, I run low timing, but I do it intentionally to keep my boost levels high on pump gas. I'd be concerned about running 13-14 degrees on cast internals since the excess heat that low timing creates isn't a good thing. Forged internals wouldn't care and are more resistant, but you're really riding the line there.

Run a boost leak test and see what you come up with. I'll bet you find something off in the setup. It's either that or your correction values for the AFC/MAFT are too rich and it's not advancing the timing enough. Still you should be seeing 16 degrees above 2.1 g/rev on the ECU's highest airflow map and with piggyback compensation it should be considerably higher (18-20 degrees).

Run a log for third gear WOT from 3-7K and post it up so we can have a look. Also post your correction factors at all of the relevant RPM points so we can see what's up. Also, how high are you revving that you're barely getting into 4th by the end of track?

 

[CanadianTSi]

A Boost leak should give him abnormally high airflow numbers, no?

I still say its that damn MAF-T screwing everything up.

My car with a 50 trim at 20psi on pump gas was doing 112mph traps, just to give you an idea.

 

[madman]

Also, how high are you revving that you're barely getting into 4th by the end of track?

I'm shifting at 7k each gear.

Would earlier shifts help, keeping it more in the higher torque range, before it starts to fall off?

 

[madman]

It's either that or your correction values for the AFC/MAFT are too rich and it's not advancing the timing enough.

The values are pretty close to where the dyno shop in St. Louis left them months ago. I will try to post them with a log soon but the lower rpm range is about 5 - 10% richer then the higher, which my mechanic also thinks may be too rich and like you said, keeping the timing from advancing soon enough.

I'm not ruling out the MAF-T either.... I might have a way to get a hold of a BOV that recirculates and try to go back to the stock mas.

I also found another awd dyno closer to me so first step will be getting it back on the dyno and see if we can get the timing right.

 

[andymoraitis]

Ty's probably right about the airflow signal on the MAFT and that may very well be the culprit.

In any event, I had low trap issues from being pig rich. If you can pinpoint any boost leaks and have them run a wideband on the dyno, that'll tell you where the tuning issues lie with respect to A/F and timing. If you're using a piggyback and not raising the timing with 650's, either it's still way too rich, or it's leaking a ton of boost. It could even be both.

As far as your shift points, those are fine.

 

[andymoraitis]

A Boost leak should give him abnormally high airflow numbers, no?

I'm not trying to debate, because I've been known to make my fair share of mistakes, but I would think if he's leaking before the MAFT, that the signal would be lower. On a 2G MAF that's before the turbo, I would say that airflow readings would be higher irrespective of the leak location since the turbo will pull more airflow to sustain boost in the presence of a leak.

If I'm off in my assumption, please let me know.

 

[CanadianTSi]

Your right Andy, I was thinking 2G mas and not Maf-t.

 

[andymoraitis]

No worries. I do have to agree that something's up in the tune or the MAFT though. I guess we'll see when the boost leak test results come back.