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Cal-look/High Performance => Cal-look => Topic started by: 67worshipper on October 16, 2008, 20:25:33 pm



Title: RPM cruising speed.
Post by: 67worshipper on October 16, 2008, 20:25:33 pm
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.


Title: Re: RPM cruising speed.
Post by: Jim Ratto on October 16, 2008, 20:36:00 pm
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.

 ;D
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.


Title: Re: RPM cruising speed.
Post by: nicolas on October 16, 2008, 20:37:20 pm
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


Title: Re: RPM cruising speed.
Post by: 67worshipper on October 16, 2008, 20:56:22 pm
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 ;)


Title: Re: RPM cruising speed.
Post by: Jim Ratto on October 16, 2008, 21:18:05 pm
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.


Title: Re: RPM cruising speed.
Post by: 67worshipper on October 16, 2008, 21:29:36 pm
im going to look that thread out now jim. ;)


Title: Re: RPM cruising speed.
Post by: Donny B. on October 17, 2008, 00:14:44 am
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. 


Title: Re: RPM cruising speed.
Post by: Zach Gomulka on October 17, 2008, 00:34:05 am
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


Title: Re: RPM cruising speed.
Post by: Rennsurfer on October 17, 2008, 01:28:23 am
You guys use tachometers? Heavy. I use my ears. Only my BMW and Porsche had tachs.


Title: Re: RPM cruising speed.
Post by: Jason Foster on October 17, 2008, 02:27:51 am
 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


Title: Re: RPM cruising speed.
Post by: Hotrodvw on October 18, 2008, 04:34:26 am
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. 


Title: Re: RPM cruising speed.
Post by: JS on October 18, 2008, 06:45:10 am
IŽm at about 4000rpm at 65mph. With noisy aftermarket gears and a loud A1 muffler. To be honest itŽs not very comfy and I donŽt use the car as much as I used to.  ::)
Maybe IŽll build a nice old school 1776 with dual quietpacks and put in a 3.88/0.885 box in a couple of years. WeŽll see.


Title: Re: RPM cruising speed.
Post by: 67worshipper on October 18, 2008, 11:33:32 am
whats your 4th gear and R+P then JS?


Title: Re: RPM cruising speed.
Post by: Bewitched666 on October 18, 2008, 11:58:31 am
I cruise in the rpm range like Jim Ratto and that equals round 120 km per hour on the dutch freeway 8)


Title: Re: RPM cruising speed.
Post by: Harry/FDK on October 18, 2008, 14:19:35 pm
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. :D


Title: Re: RPM cruising speed.
Post by: JS on October 18, 2008, 17:18:23 pm
whats your 4th gear and R+P then JS?

ItŽs 3.88 and 1.12 and I MEANT 70mph not 65. My kmh to mph conversion is a little rusty.  ;)
Earplugs do help.


Title: Re: RPM cruising speed.
Post by: Lee.C on October 18, 2008, 17:29:52 pm
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  :)


Title: Re: RPM cruising speed.
Post by: 67worshipper on October 18, 2008, 19:34:21 pm
i need to get myself some ear defenders or an MP3 for the motorways


Title: Re: RPM cruising speed.
Post by: Hotrodvw on October 18, 2008, 23:24:44 pm
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??


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 01:13:59 am
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! :)


Title: Re: RPM cruising speed.
Post by: Hotrodvw on October 19, 2008, 01:17:24 am
Seems like really tall gearing!!


Title: Re: RPM cruising speed.
Post by: Zach Gomulka on October 19, 2008, 02:04:46 am
225/70s work out to be 27.4"... mathematically :o


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 02:30:19 am
225/70s work out to be 27.4"... mathematically :o

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



Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 02:43:17 am
Hey guys I just checked tire height again proplery and yes they are a shade over 27" tall


Title: Re: RPM cruising speed.
Post by: 63 ripper on October 19, 2008, 09:58:55 am
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


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 10:10:31 am
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!



Title: Re: RPM cruising speed.
Post by: 63 ripper on October 19, 2008, 10:23:27 am
bit touchy eh ? :P
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


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 10:38:01 am
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  :)


Title: Re: RPM cruising speed.
Post by: Harry/FDK on October 19, 2008, 11:31:15 am
Plus Lee's car weight is next to nothing. ;D


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 11:48:51 am
Plus Lee's car weight is next to nothing. ;D

Dam right  ;) :)


Title: Re: RPM cruising speed.
Post by: Zach Gomulka on October 19, 2008, 21:03:48 pm
I thought the 4.37 box's had an .82 fourth??


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 22:06:15 pm
Like i said dude - who the hell knows whats in there  ::) :)


Title: Re: RPM cruising speed.
Post by: 63 ripper on October 19, 2008, 22:06:57 pm
I thought the 4.37 box's had an .82 fourth??

http://www.customspeedparts.de/content/en/technic/getriebetechnik.php


Title: Re: RPM cruising speed.
Post by: Zach Gomulka on October 19, 2008, 22:26:23 pm
I just checked the factory brochures that are scanned on thesamba, and it shows the tunnel type trans through 1966 used a 4.375 with a .89 fourth.
Where did the .82 come from??


Title: Re: RPM cruising speed.
Post by: Lee.C on October 19, 2008, 22:43:20 pm
I just checked the factory brochures that are scanned on thesamba, and it shows the tunnel type trans through 1966 used a 4.375 with a .89 fourth.
Where did the .82 come from??

you are the one who wrote it dude  :D ;) :)

I have long thought that it must have had an 0.89 fourth in it but as for the other ratio's - who knows  ??? :)


Title: Re: RPM cruising speed.
Post by: Bruce on October 19, 2008, 23:51:24 pm
A .82 comes from a Bus 'box.


Title: Re: RPM cruising speed.
Post by: 8 spoke on October 20, 2008, 05:01:24 am
Is 5 thousand rpm to high to drive with stock motor


Title: Re: RPM cruising speed.
Post by: Bruce on October 20, 2008, 06:32:40 am
yes


Title: Re: RPM cruising speed.
Post by: Zach Gomulka on October 20, 2008, 18:01:31 pm
I almost blew up a stock single port motor after about 30-45 minutes at 4400 rpm. Had me scared as I was a long way from home and it was my only transportation!


Title: Re: RPM cruising speed.
Post by: Lee.C on October 20, 2008, 18:05:45 pm
Is 5 thousand rpm to high to drive with stock motor

Dam right it is  ;) :) I don't know if a "stock" motor would get that high in top (4th) :-\ :)


Title: Re: RPM cruising speed.
Post by: Fasterbrit on October 20, 2008, 20:53:10 pm
Plus Lee's car weight is next to nothing. ;D

It wasn't on the way back from Norway! All those trophies weighed down the little Manx  ;)


Title: Re: RPM cruising speed.
Post by: Lee.C on October 20, 2008, 20:58:28 pm
Plus Lee's car weight is next to nothing. ;D

It wasn't on the way back from Norway! All those trophies weighed down the little Manx  ;)

Na I got my convoy to carry them all :D :D :D


Title: Re: RPM cruising speed.
Post by: nicolas on October 20, 2008, 21:06:18 pm
Plus Lee's car weight is next to nothing. ;D

It wasn't on the way back from Norway! All those trophies weighed down the little Manx  ;)

Na I got my convoy to carry them all :D :D :D

mentioning that, i still have one off you. the nice one with the cool writing on the disc. that one will find it's way to you for sure, but i wouldn't want it to get lost or broken in the postage. it is allready a bit loose due to the water... but in good hands

what speed were you driving when we went to Norway? i was at 100km/h when Frank was up front and 110 when Richie was leading (that was 3500rpms) i didn't like it very much at the time, but now i think it is a good cruising speed and rpm. i have a short beetle gearbox and had 165 tires at the time.


Title: Re: RPM cruising speed.
Post by: Lee.C on October 20, 2008, 21:13:19 pm
Plus Lee's car weight is next to nothing. ;D

It wasn't on the way back from Norway! All those trophies weighed down the little Manx  ;)

Na I got my convoy to carry them all :D :D :D

mentioning that, i still have one off you. the nice one with the cool writing on the disc. that one will find it's way to you for sure, but i wouldn't want it to get lost or broken in the postage. it is allready a bit loose due to the water... but in good hands

what speed were you driving when we went to Norway? i was at 100km/h when Frank was up front and 110 when Richie was leading (that was 3500rpms) i didn't like it very much at the time, but now i think it is a good cruising speed and rpm. i have a short beetle gearbox and had 165 tires at the time.

I still have your radio too dude  ::) :)

as for RPM's I NEVER went above 3200 in fourth (max 80mph) but on average I was at 2800-3000rpm and I still went through LOADS of fuel  ::)

BUT in 3rd in a tunnel now thats a different matter  ;) :)


Title: Re: RPM cruising speed.
Post by: louisb on October 20, 2008, 21:33:07 pm
i need to get myself some ear defenders or an MP3 for the motorways

I was thinking of getting a set of pilot's helmets and hooking up the mics so my passenger and I could talk when I drove the '67 with stock gears. Just need a set of Aviators and you would be good to go.  ;D


Title: Re: RPM cruising speed.
Post by: 67worshipper on October 20, 2008, 21:35:53 pm
i need to get myself some ear defenders or an MP3 for the motorways

I was thinking of getting a set of pilot's helmets and hooking up the mics so my passenger and I could talk when I drove the '67 with stock gears. Just need a set of Aviators and you would be good to go.  ;D
  ;D ;D ;D


Title: Re: RPM cruising speed.
Post by: Hotrodvw on October 21, 2008, 05:47:31 am
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!




So here's another question regarding this info......   cruising at 'normal' fwy speeds, aren't you in fear of over heating or under cooling the motor due to lack of fan speed??  I've always heard that the fan speed needs to be up over 3k rpm to cool properly......or at least it's ideal anyway.


Title: Re: RPM cruising speed.
Post by: Gabetion2000 on October 21, 2008, 06:44:39 am
I had my trans guy put an .82 4th (4.12 rp) just so I could cruise a little bit faster. At 3500 im in between 75-80mph. At 4000 im around 90 mph, and can cruise there all day. The car feels best around 34-3700 rpm though. Driving in 90+ degree heat , the head temps never saw more than 320 and oil temps never went over 200. this was on my drive to cal speedway last year , from 2 hours away. 2276 45 dells.


Title: Re: RPM cruising speed.
Post by: alex d on October 21, 2008, 09:02:48 am
my bets are that monkyboy's tachometer is reading low  ;D ;D


Title: Re: RPM cruising speed.
Post by: Lee.C on October 21, 2008, 09:50:33 am
my bets are that monkyboy's tachometer is reading low  ;D ;D

Nope checked and double checked  :)

WHY DOES NO ONE BELIEVE ME  ??? :) 3000rpm = 75mph!!!


Title: Re: RPM cruising speed.
Post by: Torben Alstrup on October 21, 2008, 10:15:45 am
my bets are that monkyboy's tachometer is reading low  ;D ;D

Nope checked and double checked  :)

WHY DOES NO ONE BELIEVE ME  ??? :) 3000rpm = 75mph!!!
BECAUSE ! - with a 165 rear and a tranmission with 3,88 R/P AND 0,82 4rth you only go 115 km/h at 3000 rpm. (71,5 mph) You have a serius error in your speedo, and perhaps also your tacho (But thats not uncommon)
IF you were correct, it would seriusly overheat your engine unless you had a very good combo along with Nikasil cylinders.

A 4,37 R/P with 0,89 4rth and 165 rears does 94 km/h @ 3000
Same with 0,82 does 102 km/h.
A 4,125 R/P with 0,89 does 100 km/h
A 3,88 R/P with 0,89 does 106 km/h

Go check your speedometer against milestones or a GPS (Which might be easier nowadays)  YoulŽll be in for a surprise.
T
PS. The 0,82 4rth came in some of the late type 14 ghiaŽs along with 4,125 R/P.


Title: Re: RPM cruising speed.
Post by: Lee.C on October 21, 2008, 10:46:46 am
my bets are that monkyboy's tachometer is reading low  ;D ;D

Nope checked and double checked  :)

WHY DOES NO ONE BELIEVE ME  ??? :) 3000rpm = 75mph!!!
BECAUSE ! - with a 165 rear and a tranmission with 3,88 R/P AND 0,82 4rth you only go 115 km/h at 3000 rpm. (71,5 mph) You have a serius error in your speedo, and perhaps also your tacho (But thats not uncommon)
IF you were correct, it would seriusly overheat your engine unless you had a very good combo along with Nikasil cylinders.

A 4,37 R/P with 0,89 4rth and 165 rears does 94 km/h @ 3000
Same with 0,82 does 102 km/h.
A 4,125 R/P with 0,89 does 100 km/h
A 3,88 R/P with 0,89 does 106 km/h

Go check your speedometer against milestones or a GPS (Which might be easier nowadays)  YoulŽll be in for a surprise.
T
PS. The 0,82 4rth came in some of the late type 14 ghiaŽs along with 4,125 R/P.

Again why does no one believe me  ??? I have checked both the tacho (against a timing light) and confirmed the speed with my satnav!

I am NOT running 165 tires on the rear mine are 225's as previously mentioned, I have NO idea which ratio's or R/P are in it.

I am not going to lie about something like this - why would I  :-\

All I know is:

65mph = 2500rpm

70mph = 2800rpm

75mph = 3000rpm

80 mph = 3200rpm


Also just out of interest - on my resent trip to norway I was following 2 tow vehicles which couldn't really go much more than 65/70mph and guess what my speedo said 65/70mph and my tacho NEVER went above 3000rpm even when I was overtaking

If one thing is clear from this thread its that you can't really tell what in a G/box unless you strip it down and check  :)



Title: Re: RPM cruising speed.
Post by: Lee.C on October 21, 2008, 10:55:09 am
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!




So here's another question regarding this info......   cruising at 'normal' fwy speeds, aren't you in fear of over heating or under cooling the motor due to lack of fan speed??  I've always heard that the fan speed needs to be up over 3k rpm to cool properly......or at least it's ideal anyway.

Thats why I have an HP1 (too big really but it helps with cooling) and a cooler - just in case - But when we checked the cylinder head temps on our trip to norway - mine were just a little cooler than my friends in his fastback (only a couple of degs) :)


Title: Re: RPM cruising speed.
Post by: alex d on October 21, 2008, 11:58:42 am
ok, with 225/70/15s, 3,875 r&p and 0,89 4th gear we get this:

3000 rpm= 114,12 km/h=70,91mph
4000 rpm=152,16km/h=94,54mph
5000 rpm=190,2 km/h=118.18mph

with a 0,82 (bus) 4th:

3000 rpm=123.86 km/h=76.96mph
4000 rpm= 165,15 km/h=102.62mph
5000 rpm= 206.44 km/h=128.28mph  :o


Title: Re: RPM cruising speed.
Post by: Neil Davies on October 21, 2008, 12:03:08 pm
and if I get up to 4000 in forth then I am doing nearly 100mph 
[/b]


ok, with 225/70/15s, 3,875 r&p and 0,89 4th gear we get this:

4000 rpm=152,16km/h=94,54mph


Looks like you've got a GT 'box there dude! ;)


Title: Re: RPM cruising speed.
Post by: j-f on October 21, 2008, 12:05:31 pm
I have a 3.875 gearbox with 165-15 rear tires (AO code)
 
And on the trip to Norway when I followed this crazy English in his plastic car (  :D ), my tacho never went over 3.000 - 3.200 rpm also. I'm not sure of the speedo as I run 145-15 front tires but on the nav sat I think 100km/h is about 2800rpm

This a pic I took on the way back from SCC. (The oil temp gauges is not functional)





Title: Re: RPM cruising speed.
Post by: Lee.C on October 21, 2008, 13:13:44 pm
ok, with 225/70/15s, 3,875 r&p and 0,89 4th gear we get this:

3000 rpm= 114,12 km/h=70,91mph
4000 rpm=152,16km/h=94,54mph
5000 rpm=190,2 km/h=118.18mph

with a 0,82 (bus) 4th:

3000 rpm=123.86 km/h=76.96mph
4000 rpm= 165,15 km/h=102.62mph
5000 rpm= 206.44 km/h=128.28mph  :o

and if I get up to 4000 in forth then I am doing nearly 100mph 
[/b]


ok, with 225/70/15s, 3,875 r&p and 0,89 4th gear we get this:

4000 rpm=152,16km/h=94,54mph


Looks like you've got a GT 'box there dude! ;)




THANKYOU DUDE  ;D At last we know what box it could be :) I'm glad neil noiticed I said "nearly" 100mph  ;)

Me and my freinds have been talking about my box for AGES - Just seems I got lucky and it works PERFECT with my set up/tires etc,

I can't wait to see what its like when I fit the dual carbs  :o :)


Title: Re: RPM cruising speed.
Post by: 63 ripper on October 21, 2008, 14:32:35 pm
if you really want to find out,count the teeth on the ring gear. take the drain hole plug out and use a torch and a marker pen.

35 teeth is 1200/1300
33 teeth is 1500
31 teeth is GT/1303S


Title: Re: RPM cruising speed.
Post by: Lee.C on October 21, 2008, 15:08:06 pm
na I'm happy with alex's sums  ;) :)