I upgraded the chip in my megasquirt from MS1 to MS2.
It is amazing what the programmers managed to get out of the MS1 chip, it was designed to run fuel injection, but with the megasquirt extra code, it runs ignition and fuel injection, this means that the timing precision required is around 100x more challenging (i.e. instead of a squirt or several per revolution, ignition requires precision of a degree or so per revolution).
I had been running into the limits of the MS1 chip for a while. It couldn't keep up with my 36-1 trigger wheel, so I converted the wheel into a 12-1 and it was fine, although sometimes the rpm went a bit funny at 10500rpm (perhaps the rev limit coming in early, not sure). Additionally I was limited with acceleration enrichment (you can do MAP or TPS based with MS1, but with MS2 you can blend the two). Next the TPS resolution was a bit of a problem with MS1, so I added a parallel resistor to improve the resolution at closed throttle positions. Finally, when I changed to secondary injection, then it was not possible to gradually ramp in the secondaries while the primaries ramp down. All in all it was time for a change.
So, Ms2 comes as a daughter card, which replaces the chip on the megasquirt board. You have to be careful to follow the instructions to the letter to avoid blowing it up. The megasquirt maps all need re-writing, but fundamentally much of this is copying from the old maps and settings.
After some messing around I managed to get the car running, and preliminary results suggest it to be much smoother and nicer. I think the ignition timing wasn't so good with the MS1, and injector timing is much better with the new chip.
Going for a 10minute drive sorted out the fueling map, so I am very pleased with it. Even on the tuning run where it was overfueling like mad (AFR of 10.5-11.0 when it should be 13 or so) it went very nicely. So I am very optimistic of how this is going to turn out.
Actually everything about it is awesome with no ned to reflash the memory to do things like updating the sensor scaling values (temp for example).
No pictures, sorry.
Building, rebuilding and running of my Sylva Stuart-Taylor GSXR1100wp engined Phoenix kit-car
Tuesday 20 July 2010
Thursday 15 July 2010
Civic injectors do fit
Just a quick photo of the GSXR and Honda Civic injectors. Only differences are the civic ones are 7mm longer, and the green tip is a bit larger. For the gsxr600 bodies the hole was large enough, for the gsxr1000 ones I needed to drill it out (annoying as an off the car job). The rubber gaskets are identical between the two injectors.
Codes on the injectors are 4109, and these are injectors from a D16Y7 civic coupe from 1998. Flow rate is 190cc/min, and opening times are 0.80ms with a 0.20ms/V sensitivity (according to www.injector-rehab.com), some claim flow of 180cc/min, all flow rates at 3ATM 43.9psi, which is something of a Suzuki/Honda standard.
Dull stuff, except if this is what you need to know!
I have a follower!!!
Welcome, Mr Ellershaw,
Never had a follower before, feels like a religious moment.
Never had a follower before, feels like a religious moment.
Tuesday 13 July 2010
De-stiffening the ARB; grinding, filing, sanding
I've been trying to workout what is going on with my anti-roll bar.
I put it onto the front of the car, and it certainly helped to make the car more stable in the corners. But, it gave me dreadful wear on the front outside tyre.
So, I hit the books to try to work out what was wrong.
ARB stiffness is a simple calculation,
Effectively the stiffness depends on the material properties, diameter to the power 4 (for hollow bars you do outer diam^4 - inner diam^4), divided by the length.
Then the effect that this has on the wheels can be determined. This has two parts, one the length of the arms on the ARB, and then the motion of the wheel versus the motion of the end of the arm. By this I mean, if the arm is short then it twists the ARB a lot for a small motion of the suspension. Conversely if the end of the arm is far from the wheel then the ARB will twist less than if the ARB is actually at the wheel.
The above arm and wheel motion ratio effects come in to the second power (once for the leverage effect which gives reduced force, and once for the fact that the angle is wound up less quickly and so it gets stiffer slower).
I'm not sure that explanation will help anyone, but who knows.
My bar is 16mm diameter and 400mm long and steel, with 5inch arms. Various calculations indicated that this was around 3times stiffer than ideal (determining ideal is the most difficult thing, but if you have a bar that is stiffer than everyone elses, and some of the everyone elses are winning races, then it means it is too stiff).
Welding ARB's gets a mixed reception as a method (mine is welded) so I didn't fancy making a new bar (if I did then I would use 2mm thing CDS tube of 1/2inch diameter, and get the ends mandrel bent, maybe bend them myself cold). So I decided to reduce the outer diameter of my bar.
Lots of grinding, filing, and sanding later I went from this red thing;
To this silver thing;
Going for a drive it felt like there was more flex at the front, but this will only come in for "on the limit" handling, which isn't appropriate on the road. The original bar had a stiffness of around 400lbs/in whereas the front springs are rated at 175lbs/inch, so it was like a solid front axle. The revised bar is more like 180lbs/inch. Exact calcs are more difficult, because there is a 70mm section of 16mm, then a 330mm section of bar that is between 12.5 and 13mm. (the calculation is to determine the stiffness of each section and then combine them as (1/((1/Q1) + (1/Q2))) the same as for parallel resistors.
Some software that I received from Tim Hoverd indicates that I should go softer still (maybe 120lbs/inch, although he does have stiffer springs on the front than I do).
Anyway, hopefully it is a move in the right direction.
I put it onto the front of the car, and it certainly helped to make the car more stable in the corners. But, it gave me dreadful wear on the front outside tyre.
So, I hit the books to try to work out what was wrong.
ARB stiffness is a simple calculation,
Effectively the stiffness depends on the material properties, diameter to the power 4 (for hollow bars you do outer diam^4 - inner diam^4), divided by the length.
Then the effect that this has on the wheels can be determined. This has two parts, one the length of the arms on the ARB, and then the motion of the wheel versus the motion of the end of the arm. By this I mean, if the arm is short then it twists the ARB a lot for a small motion of the suspension. Conversely if the end of the arm is far from the wheel then the ARB will twist less than if the ARB is actually at the wheel.
The above arm and wheel motion ratio effects come in to the second power (once for the leverage effect which gives reduced force, and once for the fact that the angle is wound up less quickly and so it gets stiffer slower).
I'm not sure that explanation will help anyone, but who knows.
My bar is 16mm diameter and 400mm long and steel, with 5inch arms. Various calculations indicated that this was around 3times stiffer than ideal (determining ideal is the most difficult thing, but if you have a bar that is stiffer than everyone elses, and some of the everyone elses are winning races, then it means it is too stiff).
Welding ARB's gets a mixed reception as a method (mine is welded) so I didn't fancy making a new bar (if I did then I would use 2mm thing CDS tube of 1/2inch diameter, and get the ends mandrel bent, maybe bend them myself cold). So I decided to reduce the outer diameter of my bar.
Lots of grinding, filing, and sanding later I went from this red thing;
To this silver thing;
Going for a drive it felt like there was more flex at the front, but this will only come in for "on the limit" handling, which isn't appropriate on the road. The original bar had a stiffness of around 400lbs/in whereas the front springs are rated at 175lbs/inch, so it was like a solid front axle. The revised bar is more like 180lbs/inch. Exact calcs are more difficult, because there is a 70mm section of 16mm, then a 330mm section of bar that is between 12.5 and 13mm. (the calculation is to determine the stiffness of each section and then combine them as (1/((1/Q1) + (1/Q2))) the same as for parallel resistors.
Some software that I received from Tim Hoverd indicates that I should go softer still (maybe 120lbs/inch, although he does have stiffer springs on the front than I do).
Anyway, hopefully it is a move in the right direction.
Monday 5 July 2010
Staged injection, the search for smaller injectors
Most people are after larger injectors, that is injectors that inject more fuel. I have fitted 2 lots of injectors for each cylinder. The outer injector comes in once the air is flowing fast into the cylinder, the inner injector flows all the time.
In this configuration the fuel from the outer injector gets really nicely mixed with the air, and this also cools the air and so increases the charge density (the amount of air getting into the cylinder), both of these things are good for power.
THe problem is that my outer injectors are around 200cc/min, but the inners are around 270cc/min. The software expects the outers to be bigger than the inners and so......
So, I am hunting for smaller inner injectors. The injectors that I have are standard Keihin KN4 as supplied for GSXR motorcycles from 2000-2003 (gsxr600 all the way to gsxr1300 used these). I discovered that Keihin makes its money from supplynig Honda, and it turns out that Hondas of these eras also used these injectors (specifically the s2000, CRX, Odyssey and maybe others). So now I am hunting for a Honda with injectors smaller than 200cc/min. I found that Honda Accords have this style of injector (3 of these at a local breaker FWIW).
On this site it shows me what Hondas have small injectors:
http://www.accordinglydone.com/data/injectors.php
So I am after injectors from a Honda Civic CX with a 1.5 or 1.6litre non vtec engine. The problem is CX was only a US designation. Why is this so difficult!
Other useful pages
http://www.cadvision.com/blanchas/Ranger/AccelFuelInjectors.pdf
and
http://www.fuelinjector.citymaker.com/HONDA_FUEL_INJECTORS.html
I think I have enough information to work out which Honda part numbers relate to which flow rate, and so mayeb back to the Keihin part numbers. Not enough time to do it now though.
In this configuration the fuel from the outer injector gets really nicely mixed with the air, and this also cools the air and so increases the charge density (the amount of air getting into the cylinder), both of these things are good for power.
THe problem is that my outer injectors are around 200cc/min, but the inners are around 270cc/min. The software expects the outers to be bigger than the inners and so......
So, I am hunting for smaller inner injectors. The injectors that I have are standard Keihin KN4 as supplied for GSXR motorcycles from 2000-2003 (gsxr600 all the way to gsxr1300 used these). I discovered that Keihin makes its money from supplynig Honda, and it turns out that Hondas of these eras also used these injectors (specifically the s2000, CRX, Odyssey and maybe others). So now I am hunting for a Honda with injectors smaller than 200cc/min. I found that Honda Accords have this style of injector (3 of these at a local breaker FWIW).
On this site it shows me what Hondas have small injectors:
http://www.accordinglydone.com/data/injectors.php
So I am after injectors from a Honda Civic CX with a 1.5 or 1.6litre non vtec engine. The problem is CX was only a US designation. Why is this so difficult!
Other useful pages
http://www.cadvision.com/blanchas/Ranger/AccelFuelInjectors.pdf
and
http://www.fuelinjector.citymaker.com/HONDA_FUEL_INJECTORS.html
I think I have enough information to work out which Honda part numbers relate to which flow rate, and so mayeb back to the Keihin part numbers. Not enough time to do it now though.
Radiator fans to Radiator fan
Power management is a bit of a problem on my car. The EFI system uses a lot, and the alternator supplies very little!
One problem was that with the fans running at idle the battery went flat. This meant that I didn't know what to do in heavy traffic. Stopping the engine would mean needing to restart (flatten battery), keeping the engine running would mean the fans running (flatten battery), and setting a higher idle would mean too much heat which would cause over heating.
I have been working on generating more power (new regulator), and using less power (HID and LED lights), and now I decided to address the fan.
Initially I had a single fan from a gsxr1000. This was not ideal and at the SVA things got a bit warm. So, I added a second gsxr1000 fan. This meant that the fans cycled on and off in the required manner and all seemed good. Total power draw from these fans was 10A, but in the old days of carbs I had enough to spare (I thought this, but it might not have been true).
To address the current problems, I tried the 2 fans in series, this dropped the current draw to 2.5A, but in this mode it couldn't cool the engine sufficiently such that the fans cycle on and off. Next I tried a single fan, but this was not juicy enough either.
Plan B, get a new fan. Went down to the scrappy in Berinsfield, and had a look. Specification was 12inch diameter, less than 4inches deep, and it needed to be a sucker (i.e. behind radiator). I looked at a few (tempted by the absolutely miniscule citroen AX fan) but ended up with a Mazda 323 fan, these cars have 2 electric fans, and this is the less powerful of the two.
Fits nicely with the Polo radiator, draws 5A (12A at startup, so 20A fuse needed), cycles on and off (on for about 90seconds before temperature drops, this was on a hot day, at 1200rpm idle).
Picture needed
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