what gear to use?
Discussion
What gear do you use plodding around town at 30 mph?
For some reason I can't keep it at a steady low speed without it kangarooing.
Once over 40 it's no problem at all.
I have tried all gears, 5th is about best, but still not perfect.
The only way I can drive at a steady 30 mph is by slipping the clutch. Not good for the clutch and hard work on the left leg!
Gary
For some reason I can't keep it at a steady low speed without it kangarooing.
Once over 40 it's no problem at all.
I have tried all gears, 5th is about best, but still not perfect.
The only way I can drive at a steady 30 mph is by slipping the clutch. Not good for the clutch and hard work on the left leg!
Gary
I find that 3rd is OK for me round town but in 4th I get the same surging you describe
I take it you have a standard build AS engine with just a mechanical advance dizzy (i.e. no vacuum advance unit)? If so then the problem is because the ignition is waaay too retarded at part throttle. The mixture is burning erratically half inside but mostly outside the engine (in the headers - which is why they get very hot round the exhaust ports!). Fitting a vacuum advance unit will help a lot (but not help the spart scatter at full power which is why AS remove it).
Computer controlled spark timing is a cheap (<£200 for a Megasquirt install) and easy (4 wires and a vacuum hose) fix. That would have been my weekend job had I not had to work yesterday...
I take it you have a standard build AS engine with just a mechanical advance dizzy (i.e. no vacuum advance unit)? If so then the problem is because the ignition is waaay too retarded at part throttle. The mixture is burning erratically half inside but mostly outside the engine (in the headers - which is why they get very hot round the exhaust ports!). Fitting a vacuum advance unit will help a lot (but not help the spart scatter at full power which is why AS remove it).
Computer controlled spark timing is a cheap (<£200 for a Megasquirt install) and easy (4 wires and a vacuum hose) fix. That would have been my weekend job had I not had to work yesterday...
Computer controlled spark timing is a cheap (<£200 for a Megasquirt install) and easy (4 wires and a vacuum hose) fix. That would have been my weekend job had I not had to work yesterday...
[/quote] A Friend had the parts sent over from the US for the Megavolt, so he could run his Zetec ford motor in his 7. The parts cost $40, he soldered the board together etc, and now is running the coilpack Zetec and has a Laptop mappable Ignition for less than £50...Now thats cheap......
davefiddes said:
I find that 3rd is OK for me round town but in 4th I get the same surging you describe
I take it you have a standard build AS engine with just a mechanical advance dizzy (i.e. no vacuum advance unit)? If so then the problem is because the ignition is waaay too retarded at part throttle. The mixture is burning erratically half inside but mostly outside the engine (in the headers - which is why they get very hot round the exhaust ports!). Fitting a vacuum advance unit will help a lot (but not help the spart scatter at full power which is why AS remove it).
Computer controlled spark timing is a cheap (<£200 for a Megasquirt install) and easy (4 wires and a vacuum hose) fix. That would have been my weekend job had I not had to work yesterday...
You are right Dave, it's a standard AS unit.
My knowledge of engines is very limited, hence the crate motor which I was able to install without fuss!
At first I thought it was my driving causing it to kangaroo at low speed and all it needed was practice, but that doesn't appear to be the case after all the miles I have done.
What you say makes sense although I doubt I could install this megaspark system myself(I'm a plumber and anything electical especially car electrics I find mystifying!)
Has anyone else tried this system? Any disadvantages?
Gary
gtrclive said:
A Friend had the parts sent over from the US for the Megavolt, so he could run his Zetec ford motor in his 7.
Did you mean MegaJolt ? I know of a few folk who have these and they do work quite well. It's just a spark advance but if that's all you need why complicate things? The downside is that the box only works with a Ford EDIS ignition module and it requires a 36 toothed (with 1 missing) wheel to be fitted to the crankshaft. EDIS modules are really cheap to find in the UK for 4-pots like Zetecs but you need to import EDIS8 modules to run with a V8. Also Ford engines usually have the toothed wheel cast into their flywheel whereas it's a custom part (not off the shelf at all) for SBCs. One up side is that you do get distributer-less ignition. The dizzy is only used to run the oil pump.
The MegaSquirt stuff should work fine in an AS engined Ultima. It would be great if you had MSD 6 or 6AL but it's not essential. The tricky part of the install seems to be mechanical. You have to open up the distributer and lock out all advance mechanisms which according to the MSD dizzy manual is pretty easy. The next bit I'm not so sure about yet: You have to slew the trigger relative to the rotor arm/cap so that the cap and rotor arm line up when you want the spark to happen but so that the points trigger 45 degrees BTDC. This gives the computer a chance to insert the appropriate advance timing delay before the spark.
The wiring boils down to feeding ignition +12V, distributer out, MSD spark in and ground into the Megasquirt box. The vacuum pipe needs to be connected to a non-ported vacuum source (on a Holley this is one of the ones at the base of the carb). All of the rest of the wiring is for fuel injection which can safely be ignored!
You don't need much of a laptop either. Anything that will run Windows 95 or later will do. I'm using a 10 year old 486 that was a throw out from work... Newer laptops can be an issue because they don't have serial ports but USB-serial dongle thingies can be had for not much money.
Unfortunately I can't say it is brilliant and will definitely solve our kangaroo problems as I've only got the parts sat on my bench/desk so far. In the next month or so I should get them in the car and I'm hoping to start up a weblog to document the process, blow by blow. Assuming it does work and makes the car run great; I'd be more than happy to get a MegaSquirt kit and assemble and test it for you (or any other Ultima owner who is interested) and help out with any installation issues.
gtr-gaz said:Hi Gary,
What gear do you use plodding around town at 30 mph?
For some reason I can't keep it at a steady low speed without it kangarooing.
Once over 40 it's no problem at all.
I have tried all gears, 5th is about best, but still not perfect.
The only way I can drive at a steady 30 mph is by slipping the clutch. Not good for the clutch and hard work on the left leg!
Gary
I am speaking a little out of turn here, as I don't have an Ultima yet. But, I can't believe the Ultima would be happy in 5th and 30 mph under any conditions.
As I understand it, the Ultima is capable of nearly 100 mph in second gear. In second gear, you would be turning about 2,300 to 2,400 RPM at 30 mph. That's a perfect RPM, if you are about to jump on the loud peddle and blow someone off the road. My guess is that third gear would put your RMP somewhere around 1,700. Without knowing the character of the AS engine, that may be too low an RPM for smooth operation.
Let us know...
-- Scott
without changing the gearing you will not get a 100mph 2nd gear.
usually 2nd is around 70-80mph.
My car did have a 100mph 2nd gear but only because the gearing was changed and that left me with a 60mph 1st gear.
It was a toss up between whether to use 1st (3500rpm) or 2nd (2100rpm) at 30mph, however anything below 30mph required 1st gear to be happy.
It's only because you have huge hp and a loud exhaust that you have this trouble.... with any other car you'd just use it at the relevant rpm and not even know you were doing it.
BTW I had an AS 526bhp engine with solid lifters.
usually 2nd is around 70-80mph.
My car did have a 100mph 2nd gear but only because the gearing was changed and that left me with a 60mph 1st gear.
It was a toss up between whether to use 1st (3500rpm) or 2nd (2100rpm) at 30mph, however anything below 30mph required 1st gear to be happy.
It's only because you have huge hp and a loud exhaust that you have this trouble.... with any other car you'd just use it at the relevant rpm and not even know you were doing it.
BTW I had an AS 526bhp engine with solid lifters.
andygtt said:Understood. All this talk of gears and speed has got me drooling again. Must get a GTR to quench desire.
without changing the gearing you will not get a 100mph 2nd gear.
usually 2nd is around 70-80mph...
The only gearing I have been working on lately is that of my snow-blower. We've had 60" in the last 8 days.
-- Scott
Reno, NV
builder said:
without changing the gearing you will not get a 100mph 2nd gear.
usually 2nd is around 70-80mph...
Understood. All this talk of gears and speed has got me drooling again. Must get a GTR to quench desire.
The only gearing I have been working on lately is that of my snow-blower. We've had 60" in the last 8 days.
-- Scott
Reno, NV
So you want a Ultima for a Snow plough then..... AH all becomes clear...
gtrclive said:
So you want a Ultima for a Snow plough then..... AH all becomes clear...
LOL! The auger would have to be on the roof! Should be able to clear the neighborhood in just a few minutes. Does anyone make 335-30/18 stud radial snows?
>> Edited by builder on Tuesday 11th January 23:59
Just had a blat today and thought I would check the revs and gear at 30mph (because I didn't ever note the gear)
Turns out on my 500BHP I use 1600rpm 4th gear It's fine and accelerates adequately
from 1600 rpm without any hesitation. Of course, even better in 3rd!
Was a little greasy on the roads today to say the least! But the road into Alton from Lasham was quiet
Turns out on my 500BHP I use 1600rpm 4th gear It's fine and accelerates adequately
from 1600 rpm without any hesitation. Of course, even better in 3rd! Was a little greasy on the roads today to say the least! But the road into Alton from Lasham was quiet
andygtt said:
It was a toss up between whether to use 1st (3500rpm) or 2nd (2100rpm) at 30mph, however anything below 30mph required 1st gear to be happy.
It's only because you have huge hp and a loud exhaust that you have this trouble.... with any other car you'd just use it at the relevant rpm and not even know you were doing it.
Yes, you were absolutly right there!
Took it out for a spin today and as long as it was above 2000rpm it was fine!
Iv'e been so used to driving diesels for god knows how many years, it does'nt matter what gear you use in them.
Guess I got a lot to learn. Never had anything even remotely like an Ultima before. Sad I know!
Which brings me to another point.
An inexperienced driver (to fast cars) could easily crash one of these.
When I was looking into buying a Caterham, they told me a driving course was included in the price of the superlight.
Perhaps Ultima should do the same, or at least advise you to take one yourself.
Gary
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