RPM cruising speed.

[67worshipper]

An answer to another question from Mr.Ratto im intregued to know what cruising speed you guys have or what speed your happy with on the highways or motorways.Jim said that he likes 4200 rpm which stunned me as i didnt think anything over 3500 was a cruiser.This speed all hinges on your 4th gear ratio and R+P combo.

[Jim Ratto]

An answer to another question from Mr.Ratto im intregued to know what cruising speed you guys have or what speed your happy with on the highways or motorways.Jim said that he likes 4200 rpm which stunned me as i didnt think anything over 3500 was a cruiser.This speed all hinges on your 4th gear ratio and R+P combo.

 
I've never liked driving my car on freeway under 3800 or so. It just kind of falls into a cruise around 4-4200, runs cool, and gets me where I am going quickly.

I've never understood the freeway flyer thing. To me a supertuned VW likes revs, and it's air cooled. Most of the engines I've built for my car are happiest up at that rpm too. If I drive it slower, it actually heats oil a little more (I wrote about this somewhere a few months ago on Lounge), and the carbs are in that transition between idle and main... something you can feel more than anything. I've had idle-air holders come loose (unscrewed) and have a cylinder fall off, and that gave me an indication where the main comes in strong, which in my car is just under 4K.

[nicolas]

well i will be honest about this and i like an RPM off 3500. that because it is a good compromise between speed and noise. when i went to Norway i had to drive at 110 km/h and that equals to 3500 with the short gearbox. and it felt a bit weird as all was new and i had to get confident about it. i liked 90km/h and 3000 or less rpms better. but now everything works better and the car has gone through some bugs and updates and it is a good handling and driving car now, feels much stabler as on the trip to Norway. so now i like speeds off 110 and 120 km/h. so i could cruise all day long at 4000rpm because it wont heat up or give a bump or anything.
that is also the reason i will switch to an even shorter gearbox with a 3.88 RP and a 1.12 th gear.

nontheless a 5speed does sound tempting and would improve gasmilage

[67worshipper]

this is all interesting stuff.sorry jim didnt see your post about this before.with all the parts balanced and these engines being able to rev more freely im assuming the rev range would be getting higher up.my 3.88 R+P and 1.21 4th might be ok after all

[Jim Ratto]

this is all interesting stuff.sorry jim didnt see your post about this before.with all the parts balanced and these engines being able to rev more freely im assuming the rev range would be getting higher up.my 3.88 R+P and 1.21 4th might be ok after all

oh that's ok... no problem. 
we were talking about using VW bypass parts from relief valve... JHU had created the thread. I was mentioning that my motor, despite higher CR runs cooler on freeway than my lower CR motor from last year.

[67worshipper]

im going to look that thread out now jim.

[Donny B.]

When I was driving all over the country a few years back I usually cruised at 3600rpm to 3800 rpm.  I found that when I upped my rpm from 3200 to 3600 rpm my oil temps dropped at least 10 degrees.  On the way home from California I would usually start smelling the barn and up the rpm to around 4k.  That worked out to about 79-80 mph for my gearing and tires.  On a trip to Denver a friend followed me at 75mph for hours.  He had not believed that I could do that and took a picture of the speedo in the truck he was driving to prove it to others.  I like getting to where I am going and don't like being a target on the freeways.  Go with the flow. 

[Zach Gomulka]

I like getting to where I am going and don't like being a target on the freeways.  Go with the flow. 

Exactly. On our trip to Vegas I drove at about 75-85 on the interstate and about 70-80 on state highways. Almost every time I passed someone they would look at me, and then immediately look down at their speedo in disbelief

BTW, I still have stock 4.12 ratios and 195/65's

[Rennsurfer]

You guys use tachometers? Heavy. I use my ears. Only my BMW and Porsche had tachs.

[Jason Foster]

 When I ran 4.12 with a .82 I would cruise around 3200 to 3500 at about 80mph thats right about the middle of my cam and my combo likes it there. Pulls real nice. Most I had it to was 5000 in 4th with 4.12 and .82 with about a 25 inch tire (maybe someone can do that math and see where I was at) my guess 120 plus easy, it coulda gone more but that was fast enough. The trans I've had in the car for the past few months was a stock geared 4.12 box with a .89, I didn't like it. I would be around 3500 at 70 or so. The new trans I'm about to install is 3.88 with a .89 which comes out to .08 off of my 4.12 and .82 I had.  I have high compression and short rods and run an FK10 my engine is torquey and I don't like driving long distances spinning over 3500 but I could. This is my take.    Carry on.
Jason

[Hotrodvw]

I'm at about 33300-3400 at 65mph.....1641, stock '67 trans, 195/65's.  I kick it up to 75 it's pushing 4 grand easily.  I never run it at 4 grand for more than a minute at a time.  I don't have a cyl head temp gauge yet, so I'm not sure if I'm beating on it or not.  Of course, this is a non-balanced motor (I assume).  I'm not a revver.  I'd rather have the torque, run up the rpm to my shift point, and smash it.  I shift at no more than 4k. 

[JS]

I´m at about 4000rpm at 65mph. With noisy aftermarket gears and a loud A1 muffler. To be honest it´s not very comfy and I don´t use the car as much as I used to. 
Maybe I´ll build a nice old school 1776 with dual quietpacks and put in a 3.88/0.885 box in a couple of years. We´ll see.

[67worshipper]

whats your 4th gear and R+P then JS?

[Bewitched666]

I cruise in the rpm range like Jim Ratto and that equals round 120 km per hour on the dutch freeway

[Harry/FDK]

My problem is the Aluminum case. Rev it up the heads run cool, but oil/motortemp goes up. Slowing down heads get warmer, you get the pic. On the new motor the CR has been lowered from 8.7 to 8.4. Plus small twin coolers/fans under the car. Lets see what happens. I really like to go for 3800-4000 on highway speeds.

BTW On trips involving highway drives, it's always with earplugs.

[JS]

whats your 4th gear and R+P then JS?

It´s 3.88 and 1.12 and I MEANT 70mph not 65. My kmh to mph conversion is a little rusty. 
Earplugs do help.

[Lee.C]

Hmmmm very interesting guys - in my manx with Big 225's on the back and a Stock 1300 Gears this is roughly what I am cruzin at:

65mph = 2500rpm

70mph = 2800rpm

75mph = 3000rpm

80 mph = 3200rpm

and if I get up to 4000 in forth then I am doing nearly 100mph 

[67worshipper]

i need to get myself some ear defenders or an MP3 for the motorways

[Hotrodvw]

Hmmmm very interesting guys - in my manx with Big 225's on the back and a Stock 1300 Gears this is roughly what I am cruzin at:

65mph = 2500rpm

70mph = 2800rpm

75mph = 3000rpm

80 mph = 3200rpm

and if I get up to 4000 in forth then I am doing nearly 100mph 

Holy crap......what gears are you running??  What's the over all tire heighth??

[Lee.C]

Hmmmm very interesting guys - in my manx with Big 225's on the back and a Stock 1300 Gears this is roughly what I am cruzin at:

65mph = 2500rpm

70mph = 2800rpm

75mph = 3000rpm

80 mph = 3200rpm

and if I get up to 4000 in forth then I am doing nearly 100mph 

Holy crap......what gears are you running??  What's the over all tire heighth??

I'd like to know what ratio's they are too dude - The rear tires are 26.5 inches tall (Goodyear 225/70/R15's)

The gearbox casing/numbers say its a stock 1300 - all I know is I can pull over 80mph in third!

[Hotrodvw]

Seems like really tall gearing!!

[Zach Gomulka]

225/70s work out to be 27.4"... mathematically

[Lee.C]

225/70s work out to be 27.4"... mathematically

That was only a rough measurment - Plus I am only running 15psi as they are on the manx so I need them pretty soft

[Lee.C]

Hey guys I just checked tire height again proplery and yes they are a shade over 27" tall

[63 ripper]

using a gear calculator with standard 1300 ratios-4.37 r+p and a .93 fourth. add the 27.4 inch tyre size it says 80 mph at 4000 rpm and 100 mph at 5000 rpm. it is probably your speedo reading out. easiest way to verify is borrow a sat-nav
there were some 1300s with different ratios but they were semi-auto KGs

[Lee.C]

Well your gear calculator is WRONG!!!!!!!!!!!!!!!!!

I have a sat nav and these speeds are CORRECT!!!!!!!!!!!!!!

Also do you really think I would not notice that I was going 10mph faster than the rest of the traffic  I have also just got back from a 2500mile road trip where I spent hour after hour staring at my speedo and tacho so i KNOW the figures are right,

65mph = 2500rpm

70mph = 2800rpm

75mph = 3000rpm

80 mph = 3200rpm

and if I get up to 4000 in forth then I am doing nearly 100mph 

TRUST ME GUYS - oh yeah, like I said the gearbox number "tells" me its a 1300 box but that gives NO indication to whats ACTUALLY in the box - christ its over 40 years old the ratios could have been changed a thousand times by now!

Plus I have "STOCK SIZE" front tires on the manx so the speedo is reading PERFECTLY!

I don't want to sound funny but I just don't like being told I am "wrong" when I know dam well I am right!

[63 ripper]

bit touchy eh ?
it is not my gear calculator,just a standard program you can find on any website JMR,Speedshop etc
i have used it then compared it to the speeds my sat-nav has said and it is accurate.
perhaps you don't have a 1300 box then
i wasn't tellling you that you were wrong....you asked what 1300 ratios were and i posted them.dude

[Lee.C]

well its quite clear it doesn't have "STOCK" ratios - the numbers say its a "1300" box but it came from my 1972 base model 1200 so christ knows whats really inside it - These base models were abit of a mishmash of parts.

All I know is at 2800rpm I am doing 70mph 

[Harry/FDK]

Plus Lee's car weight is next to nothing.

[Lee.C]

Plus Lee's car weight is next to nothing.

Dam right