Time attack beetle

[chug_A_bug]

[QUOTE= set one for 5 lbs and and the other for 15 lbs (ie. STUN and KILL settings). [/QUOTE]

hehehe I like your thinking

[Humble]

I have a handful of pwm valves from a twin turbo subaru that I could use to control boost, but since she is a race car first it's 20-25psi all the time I've been going through the extra code for the MS2 and some of that is tempting as well. I've also thought about adding 2 more inputs to the MS2 for logging purposes, fuel pressure and MPH (i already have an elec. speedo). I got the new helper springs on her last night so she looks less like a rally car and more like a road racer.

I also discovered last night that the breather line for the 3/4 valve cover came off and everything on that side is lightly lubricated. It was a pain getting the hose back on with the oil cooler in place but it should stay put now.

[Humble]

So the shakedowns continue...

I've been driving her to work for the last couple of days and had an adventure because of it. Ran out of gas twice, first time the tank was empty and I didn't believe the gauge (it sure showed me) and the second time the high pressure fuel line popped off the fuel pump (mad sure that won't happen again). Broke down in a really pretty spot though so was was kind of nice.





And here's where I'm shaking her down, my morning commute. 218 corners, 3000 feet of elevation changes, about 17 miles, and it all looks like the pics above. It's like running 2 laps around the nurburgring every morning on your way to work.



Turned up the wastegate spring to give me as much boost as possible but I've only mustered about 10psi max due to tuning. I keep running into lean spots above 5k and hearing detonation so I've fattened up the afr target map a bunch. I'm getting terrible fuel milage however, somewhere in the are of 10mpg or less when I'm not pouring gas on the ground. Here's a log from a freeway entrance ramp, 0-70mph at not quite WOT.

[Wally]

I agree: great scenery!

The car looks very intimidating even standing still

Log is a bit worrying though:
1) you really need some sort of intercooling. If you need to pull timing to 17 degrees advance at only 10 psi, your leaving a lot of hp on the table. Also try to pull more advanve at peak torque and let advance come back slowly as rpm climbs. Knock is MUCH, much more present at peak torque than at peak power at higher rpms. Tuning is everything :-))
2) fattening up the mixture usually wastes more fuel and does not help that much for knock control; Iignition retard at the right rpms (see above) should be the appropiate action imho.
3) Your pulse withs (PW right?) are way too long for a turbo engine! You need larger injectors!
That might also explain the lean running (!) : Your running 15.5 ms at about 5000 rpm and 10 psi right?
16ms at 6000 rpm is 80% duty cycle (20ms is 100% DC). So, your 5Kprm and 15ms is already at about max duty cycle!!!
I assume your MAP fuel compensation is already accounted for in that 15 ms PW? If not and the log shows just your settings, then it would be even worse, but I suppose PW shows actual PW, so boost pressure compansation is already in that 15ms.
Anyways, it seems your injector size is too small.

I assume a lot here, so pls fill me in where I went wrong, but I think there lies your lean running, knock and bad milage issues...

Gotta love a good log

[Humble]

I think your right about the ignition for sure, checking the logs last night I've got 28* advance at 4.5K and 10psi which seems like a bit much to me.

I hope the injectors aren't too small they're 750cc's! It could be the injection method I'm using right now. On that graph at 10psi the injectors are hitting 62% duty cycle at peak of 15.4ms open time, but they are only firing every other ignition event (one bank per rotation). So I can have them fire every ignition event and that should cut the open time in half. The reason I did it that way is the large injectors don't like openning below 2-3ms so I was worried about low rpms.

I think I'll switch the injection timing to once per ignition event and see how it goes and pull some fuel/timing while I'm at it. I've been thinking more and more about reconnecting the water injection too since last night my intake temps hit 92C. Right now I'm getting 7 or so mpg which is terrible since most of my time is off boost.

[Humble]

Tuning update and more....

The car was running beyond pig rich but after a few tweaks and turning down the req_fuel (from 11ms to 6ms ) its running much better. I aslo increased the number of injections so the overall injector pulse width has been almost quartered. I turned up the waste gate as far as it would go and I'm getting 13-15psi out of the motor now, still looking for more. It's also still only winding up to 5k and I need to figure out why.

Replaced a few items on the car. I replaced the pulleys with a serpentine system, mainly to improve charging and cooling, so now the alternator charges below 2k. I also swapped out the starter for a high torque unit, and the battery for an optima red top. I finally fixed the leaky valve covers as well. It turns out they were bottoming out on the top of the rocker stands before hitting the heads fully. I ground out material in the valve covers until they fit and now they seal like a charm.

I've been trying to get in car footage but it's too violent for the camera and the camera keeps shutting off. I've disabled the drop sensor, and steady shot but it just can't cope. I could have used it today when a totally oblivous woman road raged when I tried to pass her and rammed the race car. I never imagined I'd be trading paint on the mountain but that's what happened. Damage to the race car was minimal (that i've noticed so far) the worst of it being tire scuffs and a 3" crack on the fender. There's some wear on the sidewall of the tire where it contacted her car (05 hyundai tucson) but not much. Her car took much more damage, both doors caved in, and front fender dented. I feel much more confident in the beetle when it comes to car-to-car contact now but I would rather have had it happen at the track, or not at all. We stopped and traded info, and I gave her a stern talking to about the proper use of turn outs.

Hopefully I'll get some pics and video uploaded later this week. I've also got another dyno day scheduled next monday (the 13th) so I should have video and pice for that as well.

[Wally]

Good to hear you made lots of progress! Be sure to locate the reason for not wanting to run above 5K rpm as I would really like to see good high hp results from your build!

At the hot track I logged duty cycle and were at just above 71%, but on the road (intercooler working well then) in cooler weather and a high of 81% showed (about 15ms at 6100rpm). I have 660cc (60lbs) injectors and they run at 45psi now...

[Humble]

Well I'm afraid I have some bad news to report, the motor blew on the dyno today. By the sound of it, it seems valve train related but I won't know for sure until I tear the motor down. There were a few things that didn't seem right either, the motor was only making 120hp/125trq at 13psi which is really really wrong. A 2+ liter engine with that kind of boost should be well in the 200's. I may shelf the turbo bits for now and throw in the N/A spare just to get racing by the end of the season but for now it's back to the drawing board.

I did get some pics and video and I'll toss them up as soon as I get through them. She sounded awesome during the several pulls she made it's a shame the motor let go.