V8 flatly RPMs 100s or Thousands
- Thread starter 19ED30
- Start date
Walt Dupont--Me.
Well-known member
I shift my dragster at 4500 and go through the 1/8 strip at 5500, It broke a drive shaft once and went to 7100, still holding together. Walt
Ol' Ron
Well-known member
If you're racing you shift just before the engine begins to flatten out, havee to stay on the hi side of the torque curve. Some trans have a very low 1st gear and when you hit second your already on the wrong side of the curve. You can only get the hang of it by looking at the timing sheets and blowing a few engines.
uncle max
Well-known member
19ED30
Senior Member
Rpm is rpm, it means revolutions per minute.
2000rpm is, was and allways will be 2000 rpm.
The face of the tach normally has all the info you need. For instance, if it's numbered 10, 20, 30 and so on, it'll have rpm X 100 on the face. So it means 1000, 2000, 3000 rpm and so on.
Get it?
If the tach is electric it needs to be calibrated for the amount of cylinders the engine has or it'll give phony readings. This assumes a single coil type of ignition, This is usually done via a switch or terminal change on the back of the tach.
bung some pics of the front and back of the tach your looking at using, it may also need another box of tricks that it's wired too (a signal sender type of thing) depending on make, model and age.
Martin.
2000rpm is, was and allways will be 2000 rpm.
The face of the tach normally has all the info you need. For instance, if it's numbered 10, 20, 30 and so on, it'll have rpm X 100 on the face. So it means 1000, 2000, 3000 rpm and so on.
Get it?
If the tach is electric it needs to be calibrated for the amount of cylinders the engine has or it'll give phony readings. This assumes a single coil type of ignition, This is usually done via a switch or terminal change on the back of the tach.
bung some pics of the front and back of the tach your looking at using, it may also need another box of tricks that it's wired too (a signal sender type of thing) depending on make, model and age.
Martin.
JSeery
Member Emeritus
19ED30
Senior Member
Mart
Well-known member
There is no old and new way of illustrating tach faces. The maker just has to show how many revs per minute the engine is turning. For example, in your pics the second one is numbered 0 to 30 and clearly labelled "hundreds" it is a 0 to 3000 rpm tach.
Some are numbered 0, 1, 2 etc and would be labelled "Thousands".
There is no set pattern or late and early type.
Mart.
Some are numbered 0, 1, 2 etc and would be labelled "Thousands".
There is no set pattern or late and early type.
Mart.
19ED30
Senior Member
Where RPMs read by 100s or Thousands on early Fords , if so what year did they go to thousands ?
@ gen in x100s ?
@ crank x1000s ?
How many RPMs 1000s Or 100s do you turn on your stock Flatty when you are going threw the gear's (8,500)A Rod Kicker !!!
I do know what a tachometer is used for & aware of Revolution per Minuets,
Al most all gas engine idle @ least 6 to 7 hundred RPM ,
DESIEL Maybe 400 to 1,500 RPM ( big desiel )
I am thinking that the tach that are in 100s Where not used on gas engines , I will have to Change the gearing on the tach drive @ the crank or genarotor if I am unable tofind a Vintage 4000's tach Pre 50's . Electric or Mecanical.
19ED30
Senior Member
Duhhhhhhhhhh!!!!!!!
I'm a dum -SS ! I compleatly over looked at the reading's ...
I just focused on the Where it said HUNDREDS
JSeery
Member Emeritus
Duhhhhhhhhhh!!!!!!!
I'm a dum -SS ! I compleatly over looked at the reading's ...
I just focused on the Where it said HUNDREDS
Yep, that's a 3000 rpm tach (30 x 100 = 3000). But, not sure dum-SS is the best way to look at it! The second post is a 4000 rpm tach (40 x 100 etc) and would work for a lot of flatheads. I'm assuming if you already had this all figured out you wouldn't have posted the question in the first place. Often posting something like this and getting inputs sorts out the obvious.
19ED30
Senior Member
No Joke !!! The first question was answered by Mart from the Original post ,
There where 3 question's ,, I over exsamaned & only focast on the Hundreds RPM marked on the faces of several tach's & did not look @ the number layout
Mart's quote
I used to shift at 45 hundred but after everything converted to thousands I switched to 4 and a half thousand and it goes much better.
Last edited:
Mart
Well-known member
I do apologise I thought my attempt at humour would illustrate that the two types of readout give the same result.
All is good though, we got there in the end.
Mart.
AlDeBear
Senior Member
**********
That IS funny Mart! I like your sense of humor! Brightens the day! Larry