My first 150 mile run.

It was my first time driving my car 150 miles with my newly built 1915cc on a 100 degree weather. Considering cruisin W/O a freeway flyer tranny my car did pretty good at 75mph 4000rpm for a straight hour. It was more relaxed at 3800rpm at 70 mph and the top speed was 95mph at 4300rpm. (185-65-15 tires)

So to all of you that run long trips all the time what speed/rpm do you cruise?

My ideal speed/rpm would be 85-90mph at 3500-3600rpm.

What are your thoughts?

That's great. Didn't the car show any sign of high oil temperature? I ask this because that's the displacement of the motor I have and after about 45 min to 1 hour of highway driving (60 to 65 mph) my Gene Berg oil temperature dipstick makes my oil idiot light flicker ever so subtly. If I ease it a little (55 mph) the flickering stops.

Do you have a Gene Berg oil temperature dipstick? If you don't it would be nice if you could get one and compare notes. It's also cheap insurance for your engine, only $19.50 plus shipping and a 5 min. install.

I have a Vintage 1915 with a 3:88. I usually cruise at 70mph at 3000 rpms, only because I'm not yet comfortable pushing it harder than that. After 7 months I'm still feeling out my car, but after reading your post I may try pushing it to 80mph.

Brian

Ricardo
No I do not have the Gene Berg oil temperature dipstick.Actually I do not have nothing other than oil pressure gauge.I know is very bad on my side.
The engine did not hesitate,every time I had to slow down because of traffic,It took no time to get back up to speed.

Brian
My engine is 3-4 months old with close to 1500 miles.My heads are unworked,and my 40idf's have 28vents (I can go larger,32-34)and my rockers are stock (I want 1.25-1).So with all the above and w/o a freeway flyer I guess I am happy with my engines performance.

At least from what I've learned the freeway flyer isn't such a big issue because in these engines you need the rpms for them to cool properly. I've heard that freeway flyers caould lead to overheating if not set up properly. I do have a freeway flyer in my car and I could've saved $350.00 in my turnkey build by ordering the stock 4:12.

On this subject - I have, to my knowledge, a 1600cc engine with dual solex carbs and a standard 4 spd trans. My car runs at 3800 rpm at 55mph which is considerably higher rpm's than you guys are getting. I drove the car all the way home from Melbourne, FL to Wilmington, DE (apprx 1100 miles) and ran at around 70mph the whole way without a problem. If I recall the 914 tach showed 3800 rpm at that 70 mph speed. I replaced the original 914 tach with a repro from JPS and the needle "floats" a bit, as did the 914, but now I'm in the 5000 rpm range at 70mph! Would the tach exchange have anything to do with the difference? DO you have to calibrate tachs or something? ANy help would be great! Thanks, Mickey

Tachs do have to be matched to the engine's ignition system (as well as 4, 6, 8 etc cylinders). I am quite surprised that these two tachs read such different numbers. Do you have a dwell tach that reads RPM? Use that to verify which tach is correct. Hopefully the OLD one is correct, because the RPM you show for the new one is woefully inappropriate.

If needed, you can ship the incorrect unit to Palo Alto Speedometer. They had to correct ours as the tach that came with our car was for a four cylinder and we have the six. Made for some pretty crazy readings. They do excellent work.

angela

As Angela says you can use Palo Alto Speedometer; there's also another alternative: I used North Hollywood Speedometer and they VDO'd my Chinese 356 repro tach which was acting up. They did a great job. About your 3,800 rpm's at 55 mph it seems a little bit high too; maybe your transaxle's ratio is 4:37 as on older models.

I'm gonna swing by my mechanics tomorrow to have him check things with a dwell tach. I'm kinda freakin out a little here because I don't want to be beating my car to death. How can I be sure that my car is running at the proper rpms without waiting to have the tach redone, or it bursting into flames!? The car doesn't seem to be running excessively hard (for a 4 spd). I had a 71 Karmann Ghia and a 78 Super beetle: both had 4 spds and I never had a problem - though it was a longtime ago and I don't think either had tachs? I'm having a difficult time understanding how a car can run at average speeds at such high rpms? Any explanations would greatly be appreciated. Thanks, Mickey

Mickey, you answered your own question. If you drove a ghia with no tack, you heard the revs. I don't think any of us look at the tach to shift, and cruising is no different. If you are looking for another gear when you are at the top then chances are the ratio is wrong. Trust your experience, you can hear when it is overrevving. IMHO

Rodger

Thanks Rodger, I went by my mechanics and we checked the revs. Sure enough the tach is off. The car runs at normal revs. You know how it is: You have your gut but when you see something in "print" sometimes you second guess yourself. Thanks, Mickey