OK guys... results from yesterday's local event: Competition in my class was a little weak (my top competition either broke their car or didn't show) so I crushed my class. But I also only needed about 1 second improvement to take top indexed time! I think by driving better I could have taken off about .5 second... that leaves a requirement of .5 second improvement in vehicle setup to try and shoot for top PAX time of day. It's a pretty lofty goal... there are some REAL fast drivers in my region. Think I could do it?
I think it's honestly possible if I were to get a long-runner intake... some fresher tires, a little more alignment experimenting "magic"... maybe jazz up the revv-limiter/upper timing advance a little bit more... dial in my brake proportioning a little better.
Next sub-goal will be to take 1st place at the Bremerton National Tour in FSP and win 2 free Hoosier tires.
This is a big, 2-day event usually drawing in out-of-state competition (hopefully), will be happening over the weekend of July 24th-25th. Wish me luck!
UH - Jake - Standing up in the Grandstand - yelling like heck - WTG
Good luck on your next event - and thanks for posting your thoughts on tuning - I have read and am thinking!
Cheers Centurion
Shoot- guys, I've got bad news for team diesel.
At yesterday's Evolution school I went to (an all day long autocross school) in the middle of the day while I was driving my car on the practice course they had set up, I was coming out of a slalom in 2nd gear going into a straight section and it was time to accelerate, and I was revving high in 2nd gear so I went to shift to 3rd gear but I accidentically shifted it into 1st instead of 3rd! :oops:
The engine overreved higher than I've ever revved it before judging by the sound (didn't have data logging set up... wish I could have recorded how high the RPMs were!) and while the overrevving happened it also made a "crunching" sound. :shock: Later, someone observing from the back of the car (who could hear the sounds coming out of the exhaust) said it made a pop sound like a cork popping out of the wine bottle. Anyway I immediately put the clutch in, and the engine just stopped - it didn't return back to idle like I think it would have if it were undamaged. I went to restart it, and the starter motor could turn things over OK, but the engine wouldn't start and the sound it made during starting was "different" (kind of hand to describe.)
There was no oil loss, no holes punched through the block or transmission. All v-belts and the timing belt are still there and accounted for. What I think happened was I overrevved it and the valves floated. The pistons came up and smacked the valves and one or more valves must have bent. So then, with bent valves, they don't seal well -> no compression on one or more cylinders, although the motor turns over OK. That crunching noise I heard when the motor was revving high I'm thinking was the pistons hitting the valves. I don't know what the pop noise out the tailpipe could have been caused by; possibly some sort of backfire.
Anyway... I got a ride home and my Rabbit is presently still at the race site where it should be OK to leave for a few days. I haven't decided what I'm going to do.
At least ending the day on a good note, someone else taking the school offered me to co-drive their car (a new mini supercharged), which I had a blast finishing off the school in. On the final challenge match I even drove it faster than the instructors could manage.
Dang dude...that sucks! :evil:
well - Crap on a bun - no very apetizing - but - Hope the rebuilt goes well -
still waving the flag for yah!
Aw, thanks for the consolation, guys. :cry:
Here's how high I figure I must have revved the motor. Gear ratios for my "4k" transmission are: 1st, 3.45, 2nd, 2.12. When racing it I usually revv it until the revv limiter starts to limit fuel before shifting into the next gear, but also try to match the shift with a turn when possible, which I'm estimating input the RPM in 2nd at time of shift around 5000rpm or maybe a little higher, but probably not much higher than 5500rpm.
Going from 2.12 to 3.45 is a 63% gain in RPMs. So if I was at 5000rpm in 2nd gear, I would have revved it to 8150rpm in 1st, assuming the car didn't slow down at all. 5500rpm in 2nd would have put me at 8965rpm in 1st with no car slowdown. I have no doubt that the car slowed down some when downshifting, so maybe this range wasn't reached, but I'd say it's likely that it went over 7000rpm. I've heard that a solid lifter "JH" vw gas motor will start to float valves at about 7000rpm, so if the valvetrain is about the same on a 1.6l, that sounds right that I would have experienced valvefloat when I misshifted into 1st.
The experiment that will be interesting to get out of this experience, will be to see if the bottom end escaped unscathed (took the >7000rpm abuse) or not. As far as I can tell so far, no holes were punched in the side of the block, the engine still turns over, no oil was spilled out onto the track, etc, which is an encouraging sign for our motors. And remember this is with a totally-stock type prep of bottom end (no balancing or blueprinting to the bottom end, just think your basic economic "street-driver" type basic rebuild.)
I am considering slapping on a used "CY" head that my dad has, but will need to see what kind of condition it's in first. But then again, given this incident I may end up forfeiting this autocross season, as I'm getting married in September and am plenty busy with other things to do (grad school) - haven't decided yet...
:cry:
Do the JH gas motors have dual valve springs like we have?
Really sorry to hear about this Jake. You might get away with simply slapping on a new head. Keep us updated.
I'm pretty sure they use single valve springs- I'm trying to remember when I had the valve cover off of mine, but I didnt pay much attention to the springs. Either way, you'd need some REALLY stiff springs to prevent float at 8k or so.
Sorry about your incident, but it might just need a new head. It wouldnt suprise me if the pistons were fine.
That's the only thing that sucks about racing- you are bound to break something eventually.
Good luck.
Brendan
84 VW Scirocco 8v <-- JH
00 Camaro L36 M49