highway flier transmissions

Erik: I've read the same concerns regarding the use of "freeway flyer"
trannys. One way around this could be to use a smaller 356 alt/gen.
pulley to help speed up the fan.(along with a welded/balanced fan)"King" George turned me on to this idea some time ago. I'm not sure but there may be smaller dia. crank pullys to be had also. Too many times I find myself running at 4000 rpm on the highway just to keep up. This tends to bother me and plan to make a change along with a larger engine next year.
There are many here who run this set-up and I can't recall anyone mentioning problems with them.

BD

PS. Noting the time of my post, I answered your question before you asked it!

Carnac
(Message Edited 9/25/2003 6:52:26 PM)

The subject of highway flier transmissions came up. I have read and been told they can do more harm than good.

I believe the reasoning goes something like at highway speeds the engine rpm, and thus cooling fan speed, is too slow and can cause the heads to over-heat due to reduced cooling air during the hot highway runs. Moderate rpm is needed, or so I have been told. I know I will be installing head temp gauge for the next engine.

Maybe King George will comment.

In 90-100' Oklahoma, I'm not concerned with running too cool. And in 4th on freeways at 75mph + most of us are running more than sufficient rpms to build heat. In my personal experience, the 3:88, Flyer, External Cooler works great. In the Spring/Winter/Fall I bypass the stat and keep the manual fan switch off. Car runs at great temps, but requires a longer warm up. I have often wondered why all the talk...... sounds good at the bench and on paper, but out on hot asphalt, well I can run all day long. I guess if I lugged at 50 mph in 4th for loooooooong periods I could see the logic, but I don't.

And yes, I have used a 356 Pulley coutesy of George's tip. Works great, but in the end on my particular engine, driving conditions, and set up, there wasn't the need.

Good question. I am ready to learn of the downside on this too. This forum is a great place to learn, and these subjects are good fodder.
Jim

(Message Edited 9/26/2003 12:05:54 AM)

Erik, I'll call myself less of an authority than you, and you already know what a fool I am - I drove my used Speedster across the damn 100 degree desert southwest immediately after buying it! I averaged 75-80 mph, I kept my eye on the temp needle and it consistently stayed towards the cool side of its range. I could tell it moved enough that I felt sure it was working. I felt reassured the engine was not overheated at any time, although I realize that type of gauge is not regarded as precise. Car has the standard pulley and fan setup, and 3:88.

I certainly am not an authority on this subject. I have no personal experience. If you run a slightly taller rear tire in a sense you are by de facto changing to a lower gear ratio.

Another criticism I heard is when cruising at a good clip when you downshift from the "flier" fourth into a standard third gear that the rpms jump way up, potentially stressing the valve train.

I have read Jake's thoughts are on them. Maybe he will cruise through.

Sorry if this is stupid:

Isn't there a freeway flyer ring and pinion set up?
As I understand it , it would increase the ratio of all the gears.
Wouldnt this be an appropriate solution?

I am interested because my spyder needs to run at 4200 to keep up with LA freeway traffic.

Also being a cheap ass I hope this is a less expensive option than a new custom geared tranny.

The idea here is to have the correct gearing overall, not just one gear for a single purpose. Having a final drive ratio of about 3.50 to 1 with 25.25" to 25.40" load-radius tires will allow you to cruise 70 mph at about 3,250 RPM; then you could match the other gears (1st, 2nd, and 3rd) to give reasonable shift/RPM drop intervals. There are a lot of custom VW ratios available.

You could even try getting close to the original Speedster B-B-A-B overall gear ratios.

As mentioned, additional auxilliary oil coolers with thermostats and/or speeding up the fan with a 356/912 alternator pulley/hub combo can be helpful for engines that run hot or extreme climates.

By the way, you would not want a SMALLER diameter crankshaft pulley as that would slow the fan down.

Over and above that, check the "Cooling" article in KNOWLEDGE - tin fit right? Timing OK? carb jetting OK? etc.

From what I understand you can have oil temps in the "normal" range while the heads are cooking, not always but it does and can happen. People whose opinions I value rate head temp gauges as as critical, but probably not for how the normal Speedster owner drives his car.

Erik,

I concur with what you are saying regarding high head temps..... but how does that connect with "overcooling" via higher ratio R/P and a taller 3rd and 4th (which I have)? Seems to me that your head temps have more to do with how well they are cooling (fins, cleanliness, fresh air, timing, fuel, etc.). One thing I have checked is my head temps BTW. And, if I were to build this engine again I would go with the 041/042s instead of the 044s for their cooling characteristics. That's per the Book Of Jake, Chapter 1, Verse 23,,, so be it.

Again, I run 15" 185/65 tires. I have zero desire for "taller" tires. I run a 3:88 R & P, with a Transmission that has 3rd and 4th modified for a nice spread. I don't do any street light racing. Just like having my car set up for the driving I enjoy.... 40-80 MPH on 4 and 2 lanes away from the burbs. I have a welded and balanced fan, an external cooling set up with stat and fan.... and for 2 years I have had the pleasure of using this set up. I don't have a killer engine... just a strong side 1776... maybe that's part of it too? I do want a 2017 from Jake's someday as it appears to give me the 1776 reliability, cool running, with about 40 more HP. In town my car runs just like any other... I keep revs up above 2500, no lugging, and the 3:88 has little to do with my performnace needs, as hole shots are not my game. So, it runs cool due to the cooling system and quality of build. Ratios have near nada to do with the temps at those speeds. I promise my fan is spinning fast as I hardly ever see below 2000 rpms except at lights at idle. This is in 100' plus Oklahoma. It's Fall now and near 90.

Again, just my experience. I am NO EXPERT. But I darn sure like what I have..... it works... day in, day out. Driving a 250 miler tomorrow for a show as a matter of fact. Engine has 18,000 on it now and runs better than ever.

Jim (not an expert
(Message Edited 9/26/2003 1:03:37 PM)

OK, so you go to a 3.88 ring and pinion from a 4.12 - all of the gears get taller (the R/P is a multiplier). Probably not a problem with the 3.8 but maybe your 4th gear cruise RPM is still a bit high with your tire sizes.

There are also 3.44 R/P's available - might be fine for fourth, but too tall for first, second, and third, so you might want to redo the gear ratios to get the best "spread" and cruising speed (best of both worlds).

If you want to know how to do this say so and I'll post the best method for choosing ratios a street car.

The question is, at what rpm do you get the most cooling from your fan? And, is 80% maximum cooling at a lower rpm better than 100% cooling at a higher rpm. I have a so-called 'free way flier' gear ratio and I like it a lot. 70 mph is about 3400 rpm. I don't know about you, but I don't want to drive, for hours at a time, with my engine screaming at 4500 rpm. If you can drive, at 70 mph, in the mid 3000's, and run normal temps...well that's a good thing. Don't worry about freeway flier/valve troubles/fan speed and all the rest of the crap. I agree with Jim...if it works...be happy and just drive.
Ron (my rant for the day)

Ron, I was told by a local VW racer that the standard VW fan maxes out at ~4200 rpm (with a standard VW pully), and above 4200 RPM the fan doesn't cool the engine any better.

Want to talk about screaming engines - I used to have a 25' fishing boat with twin 90hp Honda 4 stroke outboards - we would take the boat from Honolulu to Molokai at 6000 RPM for 2 hrs. at a time; after 750 hrs of use on the engines, the compression was still close to new.
Those Honda engines are strong!

Dave,

Those island runs sound fun! Lived Sunset Point/Backyards on the beach from 73-79, with some time in Kona and Hanalei. 1st wife was from Kula, Maui. Met at U of H.

Jim

When the gearing is set up for less RPM at the same given speed, and the car is not lightened it is very easy to create a monster.

The engine(especially TI engines) must spin RPM to cool, else they lug and create no cooling fan speed. This will heat up heads ina heart beat.
The gearing must be matched to the tire size and the engines given torque. An engine with an adequate or superb cooling system and alot of torque can pull a higher gear successfully. An engine that is not very torquey and is out of tune and not properly set up can be fried from low revs and high load...

Big load and no fan speed = cracked heads but you will have cool oil temps..... RPM is better for an aircooled engine than lugging, nothing is worse than that.

My TIVeengines have excellent cooling and tremendous torque. We can run gearing in the very low 3 range and even into the high 2 range successfully as a final drive with no problems. the engine will get astounding fuel economy (30+)and have power and can cruise 90 all day long......Its drives like a Porshe, the way it should be.......Thats the benefit of having 23% more cooling capability.

Jim, you lived on the north shore at the perfect time - before all the crowds invaded the place.
Back in the mid '70's, I had a '74 VW camper, used to party in Waikiki, then drive out to the NS and park at Log Cabins, and surf at dawn with nobody out; nowadays there will be 50 guys out at Pipeline, before the sun rises.