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I am newly back to VW’s and am having a tough time minding my engine rpm’s. I am used to higher revving engines with my last one being a DOHC Lotus, in my Jensen Healey, that loved 7-8k rpms.
I wonder if a light bulb shining directly in my eyes would get my attention when I am really into the gas and concentrating on slaloming around the Autocross traffic cones? I’d hate to blow my engine apart but seem to have a tough time remembering to back off or shift. I have found myself over 5000 rpm a few times, to my horror.My engine seems willing to go higher than 5500 rpms. I did balance the new Mahle 1600cc pistons when I rebuilt last year, and put in new valve springs and oversize valves on ported heads now matched to a Edelbrock manifold and a 2bbl Holley carb, but I hear horror stories of these engines self destructing over 5000 rpms.This is a serious question from an old timer who has always driven hard but has no shift light, no low rpm engine, or Autocross experience. Do any of you young whippersnappers have any experience with inexpensive shift lights? I never used one. I’m not trying to go faster, more like a governor for me. I usually drive like a little old lady (on speed). Julie says that I’m too damn old to rebuild another engine.Why not swap out your tach for one that has the adjustable/resettable shift light built in? Aesthetically it might not match your dash panel as well, but it might be simpler than trying to rig something independent of your tach…
I know Sun makes them, and I think MotoMeter does also, but I’m not sure…IMO, as far as RPM, unless you’ve changed your cam, you’ll likely find that 4500-4800 is about optimum. They’ll certainly rev higher, even stock, but that’s about the top end of the peak power band…To run a VW safely and routinely over 5,000 RPM you need to work on the valve springs and push rods. You can float the valves at 5500 or so, and if you go to double or stiffer valve springs, you need to also go to stronger push rods because the stock ones will start to flex above 5500 also…You can get 7,000 RPM (or more) safely out of these flat fours, but it gets very expensive very fast. Counter-weighted crank, complete balancing, lots of head/valve/valvespring work along with getting the geometry just right, etc.While it’s fun to run high RPM, with these light cars, especially, I think it’s a lot more practical to go toward more torque and good mid-range responsiveness.
KentT2013-04-26 09:29:15Early FF TDr on 69 VW pan
Slowly coming back from the ashes...Kent, I agree with everything you said. But, as you mention, I am not willing to sacrifice the (admittedly TDr) gauges and abhor the hot rod TD look. I could, however, rig up a “plug-in” shift indicator light with hot, ground and tach sensor leads. I’m thinking removable maybe even suction cup mount.
Stock cam. Single but stiffer valve springs. Stock push rods. No crank work.Doh, I meant AutoMeter, not MotoMeter…
Some of these aren’t too obtrusive, as long as the gauge face and the color of the controls for the shift light are the same, i.e. black on black or white on white.
Early FF TDr on 69 VW pan
Slowly coming back from the ashes...Roy. Two things, one easy, and the other even easier.
Easy: what you want isn’t a shift light, it’s a rev limiter. Buy it. Install it. Be happy.
Easier: As racers have done for decades, loosen the bracket and rotate the tach so that your required rev limit–5000, say–is at 12 o’clock. Then watch it while you’re driving. That is what it is there for.
Ed, I agree that a rev limiter would provide the “safety” that he’s looking for, but they’re not really useful when you’re trying for max performance like in the AutoX you guys keep talking about.
IMO, they’re really intended to stop expensive explosions from things like missed gears when shifting, blown torque converters, etc. that could lead to over-revving. They function like a fuse/circuit breaker in an electrical circuit — i.e. insurance.They’re not intended to be used regularly. A big, obnoxious shift indicator light would serve as an RPM idiot light, and serve two purposes. 🙂Early FF TDr on 69 VW pan
Slowly coming back from the ashes...I guess the best advice is for me to get smarter about my driving and pay more attention to the Tach. I’m not sure that I have ever had an engine what would rev over the red line so willingly. Thanks.
How about something like this?
PMOSSBERG2013-04-26 22:09:21
Bill Ascheman
Fiberfab Ford
Modified 5.0, 5sp., 4:11
Autocross & Hillclimb
"Drive Happy"
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