Outer Limits 4x4 Board

macca81 wrote:dunno with the new engine, as there is no tacho on it, but the old one was 3100 in 4th

should be the same as the gearbox should be the same ratio.

although 3100 seems pretty steep for 4th.

my 40 was 2600rpm at 100. on 33's

Maruti 30" MT ,4800rpm at 100kms +/- 2ks 4th gear, no 5th.

2900 at 100 in 5th.

35's 4.88's 1HZ Turbo

Gwagensteve wrote:

zagan wrote:Are these EFI engines?

If so it'll depend on the map on the CPU as it depends on what map you use as to what the rpm will be.

an example
a bad map might be 3000rpm for 100klm chew up heaps of fuel.

A good map might be 1500rpm for 100klm and use very little fuel.

Gearing won't mean much if the engine has EFI.

Thats the best outers post ever.

Please, explain how, with a manual gearbox, in gear, driving down the road, how EFI can mysteriously change the relationship between the speed the crank is turning and the speed the input shaft of the gearbox is turning. Does a poor efi map slip the clutch?

Steve.

An EFI engine runs as lean as it can based on the map given to it.

use a crap map, will mean it'll run at a higher RPM to do the same amount of work/speed plus chew up more fuel to do it.

Use a good map it'll use less fuel plus spin up quicker due to having the correct A/F mix happening.

if the mapping never mattered you'd never need to use a chip or piggy-back box on the ECU to trick it into using a better fuel map.

Gearing only effects the top speed per gear and top speed overall, manual/auto don't matter.

bigger wheels take longer to spin up but once at the right speed ruduce the load on the engine as the weight of the turning wheels keeps them spinning for longer.

these days it's all sensors and your simply handed back what the ECU wants you to see.

Should also add depending on how new the 4wd is the speedo could be comng from the gearbox or even newer the speedo reading be coming from the wheels or axles.

So dpending on what the deal is, if it's coming from the wheel/axle some people with the larger sized wheels might not even be doing a proper 100klms in the first place, they'd be going slower due to the wheel taking longer to do a full turn.

zagan wrote:

Gwagensteve wrote:

zagan wrote:Are these EFI engines?

If so it'll depend on the map on the CPU as it depends on what map you use as to what the rpm will be.

an example
a bad map might be 3000rpm for 100klm chew up heaps of fuel.

A good map might be 1500rpm for 100klm and use very little fuel.

Gearing won't mean much if the engine has EFI.

Thats the best outers post ever.

Please, explain how, with a manual gearbox, in gear, driving down the road, how EFI can mysteriously change the relationship between the speed the crank is turning and the speed the input shaft of the gearbox is turning. Does a poor efi map slip the clutch?

Steve.

An EFI engine runs as lean as it can based on the map given to it.

use a crap map, will mean it'll run at a higher RPM to do the same amount of work/speed plus chew up more fuel to do it.

Use a good map it'll use less fuel plus spin up quicker due to having the correct A/F mix happening.

if the mapping never mattered you'd never need to use a chip or piggy-back box on the ECU to trick it into using a better fuel map.

Gearing only effects the top speed per gear and top speed overall, manual/auto don't matter.

bigger wheels take longer to spin up but once at the right speed ruduce the load on the engine as the weight of the turning wheels keeps them spinning for longer.

these days it's all sensors and your simply handed back what the ECU wants you to see.

I'd say 60 - 70% of this post is right, and the stuff that is right is good.

But the stuff that is wrong?



That first post?

Consider a manual vehicle. Crankshaft is mechanically coupled to the wheels. There are gears in between altering ratios, but turn the crankshaft and the wheels WILL turn. Select a gear (any gear) and for every turn of the crankshaft the wheels will turn the same predictable amount.

The crankshaft has NFI whether the cylinders are burning petrol or diesel, fuel injected or carburettor.

Go find an on-line gearing calculator - one that takes your gearbox ratios, final drive ratio and tyre sizes, and then tells you your speed per 1000 rpm. Does it care two hoots about your engine?

-Scott- wrote:

zagan wrote:

Gwagensteve wrote:

zagan wrote:Are these EFI engines?

If so it'll depend on the map on the CPU as it depends on what map you use as to what the rpm will be.

an example
a bad map might be 3000rpm for 100klm chew up heaps of fuel.

A good map might be 1500rpm for 100klm and use very little fuel.

Gearing won't mean much if the engine has EFI.

Thats the best outers post ever.

Please, explain how, with a manual gearbox, in gear, driving down the road, how EFI can mysteriously change the relationship between the speed the crank is turning and the speed the input shaft of the gearbox is turning. Does a poor efi map slip the clutch?

Steve.

An EFI engine runs as lean as it can based on the map given to it.

use a crap map, will mean it'll run at a higher RPM to do the same amount of work/speed plus chew up more fuel to do it.

Use a good map it'll use less fuel plus spin up quicker due to having the correct A/F mix happening.

if the mapping never mattered you'd never need to use a chip or piggy-back box on the ECU to trick it into using a better fuel map.

Gearing only effects the top speed per gear and top speed overall, manual/auto don't matter.

bigger wheels take longer to spin up but once at the right speed ruduce the load on the engine as the weight of the turning wheels keeps them spinning for longer.

these days it's all sensors and your simply handed back what the ECU wants you to see.

I'd say 60 - 70% of this post is right, and the stuff that is right is good.

But the stuff that is wrong?



That first post?

Consider a manual vehicle. Crankshaft is mechanically coupled to the wheels. There are gears in between altering ratios, but turn the crankshaft and the wheels WILL turn. Select a gear (any gear) and for every turn of the crankshaft the wheels will turn the same predictable amount.

The crankshaft has NFI whether the cylinders are burning petrol or diesel, fuel injected or carburettor.

Go find an on-line gearing calculator - one that takes your gearbox ratios, final drive ratio and tyre sizes, and then tells you your speed per 1000 rpm. Does it care two hoots about your engine?

^^^^what he said, dude, stop embarrassing yourself, the fuel map can not have a direct coralation to the revs at a given speed, the engine crankshaft is MECHANICALLY FIXED, the fuel ratio can change, and the throttle effort required, may change, but the revs can't

Maybe give this a bash

http://www.outerlimits4x4.com/phpBB2/vi ... 47&start=0

Rocky, 2.8TD, 31", stock gearing/ratios - 2600rpm @ 100km/h.

Bushy: Defender 200tdi, R380, '83 rangie 1.001:1 LT230, 3.54 diffs, 38's swampers. About 1000 to 1200rpm @ 100 (GPS)

Or at least that is what the tacho shows. Cant be bothered working it out properly.

gq td42. 4.1 diff gears n 35's 2100 @100

gunna get the map on my ecu changed to it only does 1000rpm tho as diesels getting dear

Wow Zagan.... just wow. You could make a fortune on Ebay with this

so if I run a really really good map, can I turn my 100:1 crawl ratio into a 200:1 crawl ratio?

There's so many muddled concepts in your post I don't know where to start.

Steve.

Gwagensteve wrote:Wow Zagan.... just wow. You could make a fortune on Ebay with this

so if I run a really really good map, can I turn my 100:1 crawl ratio into a 200:1 crawl ratio?

There's so many muddled concepts in your post I don't know where to start.

Steve.

Nice sig. Your really out to embarrass him aren't you

Don't you think he's doing a good enough job of that himself

what i cant understand is how a guy that has given an incorrect/confused reply to every thread he has ever answered could still think he knows the answer and post in the next thread he sees.

ps. if i made a comment like that id change my nic immediatly:P

cloughy wrote:

Gwagensteve wrote:Wow Zagan.... just wow. You could make a fortune on Ebay with this

so if I run a really really good map, can I turn my 100:1 crawl ratio into a 200:1 crawl ratio?

There's so many muddled concepts in your post I don't know where to start.

Steve.

Nice sig. Your really out to embarrass him aren't you

Don't you think he's doing a good enough job of that himself

All he needs to say is "oh yeah... I get it now, I had it round the wrong way" or something..... I wonder what he scored on the mechanical aptitude test?

Steve.

I'm just basing what I've said on what has happened to me.

I've had a EFI car suto box was doing 100kph around 1500rpm, took it to a place to get serviced and came out doing 100kph at 2300rpm.

I put it down to a poor EFI mapping, myself.

Maybe you have a different idea? same gears in the box BTW.

4500rpm in 3rd for the 2L...

Although thats pushing the truck very hard...

Think its around 2200rpm in 5th...

zagan wrote:I'm just basing what I've said on what has happened to me.

I've had a EFI car suto box was doing 100kph around 1500rpm, took it to a place to get serviced and came out doing 100kph at 2300rpm.

I put it down to a poor EFI mapping, myself.

Maybe you have a different idea? same gears in the box BTW.

Yep, when you drove there you were in overdrive with the converter locked and when you drove back, you were in 3rd.

The numbers don't lie. These are indicative only for a generic 6 cylinder road car, but here's the gist of it.

25" tall tyre, .785 overdrive, 2.75:1 rear diff ratio= 89 kph@ 1632 RPM.

25" tall tyre, 1:1 3rd gear, 2.75 diff ratio = 89 km/h @ 2079 rpm.

I could play with the figures and work out exactly what combination you have, and converter slip will make a small difference etc, but the truth of it is you were in a different gear on the return trip.


Steve.

Sierra SJ80

standard tanrsfer, diffs and tyres (26")

3750rpm @ 100km/h

cheers,
Sean

F75 rocky V6 comm

5spd 31"tyres


2200rpm @ 100km/h

Gwagensteve wrote:Yep, when you drove there you were in overdrive with the converter locked and when you drove back, you were in 3rd.

The numbers don't lie. These are indicative only for a generic 6 cylinder road car, but here's the gist of it.

25" tall tyre, .785 overdrive, 2.75:1 rear diff ratio= 89 kph@ 1632 RPM.

25" tall tyre, 1:1 3rd gear, 2.75 diff ratio = 89 km/h @ 2079 rpm.

I could play with the figures and work out exactly what combination you have, and converter slip will make a small difference etc, but the truth of it is you were in a different gear on the return trip.


Steve.

This was on a 1991 magna, there is no overdrive from memory plus it was a 4 cyclinder engine.

4 gear auto, wasn't touched in all the time.

Ran great used no fuel before it was serviced by an old mechanic at an ultratune, did a great job on it.

Then got taken to a K-Mart service centre came out like utter crap, ran poor everything, it stayed at the higher RPM for a good 8 months or so, till someone pranged into it while parked.

anyway, I took a look into this and found some interesting stuff (for me anyway) might help me out with something else.

Yep, they're a 4 speed auto. 4th gear is an overdrive. (very few 4 speed auto's have a direct 4th.. my Gwagen being one)

Here's my diagnosis.

The dodgy mechanic left something off/unplugged whatever, and the engine would not come off of closed loop, which means the engine runs on a rich fuel map with the ignition retarded. Under these conditions, it's not at all out of the question the gearbox will not go into overdrive and the torque converter will not lock because the computer is seeing a fault condition and won't let it. It will use a heap of fuel because the engine doesn't look at the oxygen sensor to see it if it's running lean or rich.

Trust me, the car was in 3rd gear after it was played with by Kmart, instead of 4th.

No, absolutely no efi map can change the speed the engine runs at in a given gear for the same road speed. You'll just have to trust us on that one.

Steve.

Gwagensteve wrote:Yep, they're a 4 speed auto. 4th gear is an overdrive. (very few 4 speed auto's have a direct 4th.. my Gwagen being one)

I believe most FWD transmissions don't have 1:1 anything. The second highest gear will be close to 1:1, but a little one side or the other, top gear well and truly overdrive. (I don't recall seeing anything different; doesn't mean they don't exist.)

Gwagensteve wrote:Here's my diagnosis.

The dodgy mechanic left something off/unplugged whatever, and the engine would not come off of closed loop, which means the engine runs on a rich fuel map with the ignition retarded. Under these conditions, it's not at all out of the question the gearbox will not go into overdrive and the torque converter will not lock because the computer is seeing a fault condition and won't let it. It will use a heap of fuel because the engine doesn't look at the oxygen sensor to see it if it's running lean or rich.

Trust me, the car was in 3rd gear after it was played with by Kmart, instead of 4th.

I'd put money on it.

Gwagensteve wrote:No, absolutely no efi map can change the speed the engine runs at in a given gear for the same road speed. You'll just have to trust us on that one.

Steve.

x2

-Scott- wrote: I believe most FWD transmissions don't have 1:1 anything. The second highest gear will be close to 1:1, but a little one side or the other, top gear well and truly overdrive. (I don't recall seeing anything different; doesn't mean they don't exist.)

You may be right - I was trying to avoid getting into specifics. My point was only that it was in one gear before the service and another after.

Steve.

Gwagensteve wrote:

-Scott- wrote: I believe most FWD transmissions don't have 1:1 anything. The second highest gear will be close to 1:1, but a little one side or the other, top gear well and truly overdrive. (I don't recall seeing anything different; doesn't mean they don't exist.)

You may be right - I was trying to avoid getting into specifics. My point was only that it was in one gear before the service and another after.

Steve.

I try to do the same, but I'm supposed to be studying - so I'll post any shit that I can.

-Scott- wrote:
I believe most FWD transmissions don't have 1:1 anything. The second highest gear will be close to 1:1, but a little one side or the other, top gear well and truly overdrive. (I don't recall seeing anything different; doesn't mean they don't exist.)

The 91 Magna had 3 different auto transaxle gearboxes, the F4A33 the KM177-6 and the KM 177, they all had the same 3rd and 4th gear ratio's 3rd was 1:1 and fourth was .685:1, the first box had a final drive of 3.958 the second two had a 3.705

So the first box

3rd gear at 100km/h would give you 3204rpm
4th gear at 100km/h would give you 2195rpm

The 2nd two boxes

3rd gear at 100km/h would give you 2999rpm
4th gear at 100km/h would give you 2054rpm

the tyre size was 185/75/14 or 24.9inch

I thinkHoppy

The final drive ratio for the KM177-6 carby engine was 3.9, but we are talking the EFI arnt we

Hoppy

The mechanic didn't screw up the tacho?

Just read through this whole thread

Gold

Hof wrote:Just read through this whole thread

Gold

X2
Hoppy

mine is



Injectored 250 x-flow, C4 auto 60's T-case with 6% reduction in High range, 37 Mickey T's Claws Bais, "D", 100km/ph at 2900-3000Rpm