CAMS?
Moderators: IMOC Moderators, IMOC Committee Members
Re: CAMS?
They are not silly low lift cams Juanwond at all!!
I took some advice from a race engine builder as to what would be good for the design of the 4age in terms of its ability to rev, overall design, head etc and he said"as much lift as you can get, 12mm would be excellent" and "you want to get it between 270 and 280 degrees that was it will have a good useable power band".
Your cams are still higher lift than standard, so for your application they are probably ideal. Remember, the cams I have had suggested to me rely on good porting work, higher compression ratio, optimised exhaust manifold, and DEFINITELY throttle body injection. They would not work any better in your configuration than yours do.
Limey, AFAIK, that lift would be considered"minimum" for the engine I wanted to build, however it really depends on the components surrounding it. If you reeled off all the above and then said 9.7 I would tell you "gains to be had going to 12mm" but I don't know the rest of the story, so hard to say.
Suffice to say, the more power you want, the more precise EVERYTHING has to be, and 1 mod could knock-on to requiring another, and another and before you know it you spend£4000 and have 190bhp!!!
I am curious to find out the maximum lift on standard top end assembly that would work with the standard exhaust manifold... I would like to "stage" my engine upgrades, and I am thinking about the whole OMEX throttle body assembly, keep the standard head/exhaust manifold and put the maximum cams in on that configuration. I would expect that to make around 155-160 at the flywheel, with another 20-30bhp coming from the higher lift cams, head work (up compression, port and polish, match the ports to the anciliaries) and exhaust manifold.
I have spoken to many people off this forum about the Mk1, and my biggest argument is it's character. I do not want to detract from it's childish, playful ar$e out (controllably) nature. this is why I don't want to go for a 300bhp snarling 3SGTE. It would be good to stage the upgrades and feel how each 10bhp felt, and at some point the power would come into line with the chassis and suspension and brakes on my car. At that point theoretically it's "finished". OMEX and appropriate cams would be a great start, costing I reckon £2000 fitted and mapped. Not cheap, but then we are on a different road-map to the turbo guys, power isn't cheap!
I took some advice from a race engine builder as to what would be good for the design of the 4age in terms of its ability to rev, overall design, head etc and he said
"as much lift as you can get, 12mm would be excellent" and "you want to get it between 270 and 280 degrees that was it will have a good useable power band".Your cams are still higher lift than standard, so for your application they are probably ideal.
Remember, the cams I have had suggested to me rely on good porting work, higher compression ratio, optimised exhaust manifold, and DEFINITELY throttle body injection. They would not work any better in your configuration than yours do.Limey, AFAIK, that lift would be considered
"minimum" for the engine I wanted to build, however it really depends on the components surrounding it. If you reeled off all the above and then said 9.7 I would tell you "gains to be had going to 12mm" but I don't know the rest of the story, so hard to say.Suffice to say, the more power you want, the more precise EVERYTHING has to be, and 1 mod could knock-on to requiring another, and another and before you know it you spend
£4000 and have 190bhp!!!I am curious to find out the maximum lift on standard top end assembly that would work with the standard exhaust manifold.
.. I would like to "stage" my engine upgrades, and I am thinking about the whole OMEX throttle body assembly, keep the standard head/exhaust manifold and put the maximum cams in on that configuration. I would expect that to make around 155-160 at the flywheel, with another 20-30bhp coming from the higher lift cams, head work (up compression, port and polish, match the ports to the anciliaries) and exhaust manifold.I have spoken to many people off this forum about the Mk1, and my biggest argument is it's character.
I do not want to detract from it's childish, playful ar$e out (controllably) nature. this is why I don't want to go for a 300bhp snarling 3SGTE. It would be good to stage the upgrades and feel how each 10bhp felt, and at some point the power would come into line with the chassis and suspension and brakes on my car. At that point theoretically it's "finished". OMEX and appropriate cams would be a great start, costing I reckon £2000 fitted and mapped. Not cheap, but then we are on a different road-map to the turbo guys, power isn't cheap!Re: CAMS?
Andy
If you're after a mappable ECU have you considered the Megasquirt? A new ones just been released and looks extremely good.
I've got a dissassembled engine in the garage at the moment and I'm slowly gathering parts, next month will be pistons(Arias high comp 10.5:1) and crank/rods/flywheel (fidanza) balancing/lightening, unless something else turns up to drain the funds (as has happened for most of this year ](./images/smilies/eusa_wall.gif "Brick wall")
).
I'm not going to do any headwork other than a good valve seating(3 or 5 angle) as I figure the large port flows a huge amount of air anyway, just changing the filter on my stock engine has lead to it running pretty damn lean. Don't really think polishing does much either. 
Chris
If you're after a mappable ECU have you considered the Megasquirt? A new ones just been released and looks extremely good.
I've got a dissassembled engine in the garage at the moment and I'm slowly gathering parts, next month will be pistons
(Arias high comp 10.5:1) and crank/rods/flywheel (fidanza) balancing/lightening, unless something else turns up to drain the funds (as has happened for most of this year ).I'm not going to do any headwork other than a good valve seating
(3 or 5 angle) as I figure the large port flows a huge amount of air anyway, just changing the filter on my stock engine has lead to it running pretty damn lean. Don't really think polishing does much either. Chris
Re: CAMS?
Hey Chris,
we should get together and have a chat...
Roger at Sabre doesn't always open out the chambers, he optimises them for the application, and he showed me a couple of heads where he had slimmed down(!!!) and reshaped the holes because they are so big, he said there would be no"inertial ramming" of the chambers and the volumetric efficiency of the engine would drop. VE is the % of the cylinder volume which actually gets in there at atmospheric pressure. IE 100% VE gives you 400cc of mixture at atmosphere. Car engines run under 100% and F1 cars way over, like 120%+ (sorry if you know that already)
He also showed me flow results from a bog standard 4AGE head(16v) and one he had modified, and the results were truly astonishing. He got more air in at a higher speed which is just what you want. FYI he reckons the 4AGE head is great.
Could you not go half a point higher on the CR? it is FREE power from tickover right through, and with a mappable ECU you can get rid of detonation totally?(oh, that's how polishing can help BTW, reduces detting) I have seen graphs where the CR was increased from 11.1:1 to 13.1:1 on NOT a 4AGE engine, and the improvement was basically 5bhp EVERYWHERE, it just clunked up the curve a notch (peak power was in the region of 130bhp)
Andy
we should get together and have a chat.
..Roger at Sabre doesn't always open out the chambers, he optimises them for the application, and he showed me a couple of heads where he had slimmed down(!!!) and reshaped the holes because they are so big, he said there would be no
"inertial ramming" of the chambers and the volumetric efficiency of the engine would drop. VE is the % of the cylinder volume which actually gets in there at atmospheric pressure. IE 100% VE gives you 400cc of mixture at atmosphere. Car engines run under 100% and F1 cars way over, like 120%+ (sorry if you know that already)He also showed me flow results from a bog standard 4AGE head
(16v) and one he had modified, and the results were truly astonishing. He got more air in at a higher speed which is just what you want. FYI he reckons the 4AGE head is great.Could you not go half a point higher on the CR? it is FREE power from tickover right through, and with a mappable ECU you can get rid of detonation totally?
(oh, that's how polishing can help BTW, reduces detting) I have seen graphs where the CR was increased from 11.1:1 to 13.1:1 on NOT a 4AGE engine, and the improvement was basically 5bhp EVERYWHERE, it just clunked up the curve a notch (peak power was in the region of 130bhp)Andy
Re: CAMS?
The Arias jobbies will hike the compression to 10.5 on stock settings, so a thinner HG would knock it up nicely I think (TRD 0.8mm). It's either that or get some from TODA but they are expensive and Arias are just up the road from me in Horsham.
Ah you were talking about polishing the combustion chamber, yeah agree with that. I also reckon you could take the knife edge off the squish area on the front and rear sides of the chamber, the high comp engine I killed earlier this year had notches all along these edges. The engine pulled very well just with filter, exhaust and higher comp (don't ask what the comp was I have no idea 
) but was seriously lean.
Deffo up for a chat sometime.
Chris
(TRD 0.8mm). It's either that or get some from TODA but they are expensive and Arias are just up the road from me in Horsham.Ah you were talking about polishing the combustion chamber, yeah agree with that.
I also reckon you could take the knife edge off the squish area on the front and rear sides of the chamber, the high comp engine I killed earlier this year had notches all along these edges. The engine pulled very well just with filter, exhaust and higher comp (don't ask what the comp was I have no idea ) but was seriously lean.Deffo up for a chat sometime.
Chris
Re: CAMS?
Limeymk1 wrote:Andy
If you're after a mappable ECU have you considered the Megasquirt? A new ones just been released and looks extremely good.
Chris
Well I hope it's better than the original MS system.
That had a tiny 8x8 table for the fuel mapping. i.e. 8 rpm mapping points across the full rev range. The resolution for the fuel pulse width was something like 100microseconds.Toytown.
...In comparison, the 21 year old mk1 MR2 ECU 89661-17030 has a 17x8
(ignition) map (17 rpm points 400-7200rpm) and has 16bit fuel injection resolution of 1 microsecond (a hundred times better resolution than MS)The mk1b ECU has over 40 lookups in it to optimise the fuelling and timing.
The ignition timing and fuelling both have 16bit resolution on this ancient old ECU.
Not bad for an old timer.
..Re: CAMS?
12x12 now Jeremy and fuel pulsewidth of 1 microsecond so a tad better. It could do with a few more rpm points IMO but there's a hell of a lot more it can do, seeing as it can control a V8s ignition and timing I'm sure there's scope for extra control on a 4 pot. I'm no expert but should be doable?
It could do with a few more rpm points IMO but there's a hell of a lot more it can do, seeing as it can control a V8s ignition and timing I'm sure there's scope for extra control on a 4 pot. I'm no expert but should be doable?Re: CAMS?
Limeymk1 wrote:12x12 now Jeremy and fuel pulsewidth of 1 microsecond so a tad better.
It's the subtle program code and maps that make the car nice to drive though.
By this I mean how the car behaves on the overrun or if you are in awkward traffic. The mk1 ECU even has different types of overrun. The mapping program code changes as the overrun stops, recovers and the revs build up again. All this code is tailored to the 4A-GE engine.Like I said, there are over 40 lookups in the ancient mk1b ECU.
I'm absolutely amazed that Megasquirt have
'only' gone up to a 12x12 table. Why not let the user define the table size to suit the car? Maybe MS have inefficient code that can't deal with big 3d tables.
The Denso code for the 17x8 3d ignition map in the MR2 mk1 ECU is an amazing example of what can be achieved with just a few bytes of fast code.
The table has full interpolation between sites in both dimensions and the code can access larger tables with no loss in efficiency. I expanded the tables to 21x10 on my ECU. At the risk of sounding like an anorak, the coding in these Denso ECUs was written by
'masters' of machine code and it is a work of art.Re: CAMS?
I will almost certainly go with a "decent" (don't flame me too much!) ECU, the one that comes with the OMEX kit seems to do the job, it's the one area that there is no point scrimping on.
When the"anoraks" say it's good, I'll get the budget option I think...
"decent" (don't flame me too much!) ECU, the one that comes with the OMEX kit seems to do the job, it's the one area that there is no point scrimping on.When the
"anoraks" say it's good, I'll get the budget option I think...-
PsychomIKE
- Posts: 130
- Joined: Fri Jan 21, 2005 12:01 pm
Re: CAMS?
Guys, what's the deal with cams and forced induction engines? Is a decent cam for N/A a decent cam for turbo etc, or do they follow different rules like exhausts etc?
If anyone knows some decent reading that'd be great.
Mike
If anyone knows some decent reading that'd be great.
Mike
-
Lauren
- IMOC Committee
- Posts: 38632
- Joined: Mon Dec 13, 2004 5:37 pm
- Location: Greater Manchester
- Contact:
Re: CAMS?
PsychomIKE wrote:Guys, what's the deal with cams and forced induction engines? Is a decent cam for N/A a decent cam for turbo etc, or do they follow different rules like exhausts etc?
If anyone knows some decent reading that'd be great.
Mike
Well the thing is with a forced induction engine is that its not really necessary to have such a long duration as the air/fuel is being forced in under pressure unlike the NA which has to rely on atmospheric pressure so the general rule of thumb is that turbo engines can run a much milder cam.
In fact the SC engine uses the same cam as the NA.. get a book on turbocharging.. years ago i bought the corky bell book: Maximum boost. This is a fairly good read and will certainly give you the background.2020 GR Yaris - Circuit Pack 
- Circuit Pack Re: CAMS?
I just like the MS because it seems such a flexible platform, it's got all the inputs that the stock ECU has plus wideband O2 and the ability to control a Nitrous solenoid. Decent reading, I'd go for A G Bell's books on Forced Induction Tuning, very readable and pretty in depth.
Amazon stock them (that's where I got mine).Re: CAMS?
has anyone done a MegaSquirt install on a 1989 NA or similar? Would be interested to talk to someone.
I tried to read up on it, does it do Ignition aswell as Fuelling? someone mentioned a squirt and spark modification you need to do?
I tried to read up on it, does it do Ignition aswell as Fuelling? someone mentioned a squirt and spark modification you need to do?
Re: CAMS?
Plenty of people have installed the MS with the 4AGE, the newer one doesn't need any modification for ignition control and you have a choice of using electronic ignition (Fords EDIS system or Bosch) or the stock dizzy.
There is another in development(isn't there always) which uses a 100MHz 32bit processor, but again only seems to have 12 x 12 tables for ignition/RPM/O2/TPS (seperate for each) although it does mention dual tables. I don't know exactly what this means but seems to suggest you could have 2 ign/rpm tables to cover a wider range, I'll have to get on the forum and do some digging.
(Fords EDIS system or Bosch) or the stock dizzy.There is another in development
(isn't there always) which uses a 100MHz 32bit processor, but again only seems to have 12 x 12 tables for ignition/RPM/O2/TPS (seperate for each) although it does mention dual tables. I don't know exactly what this means but seems to suggest you could have 2 ign/rpm tables to cover a wider range, I'll have to get on the forum and do some digging.Re: CAMS?
Limeymk1 wrote:Plenty of people have installed the MS with the 4AGE, the newer one doesn't need any modification for ignition control and you have a choice of using electronic ignition
There is another in development
100MHz and 32bit! That must surely be going OTT!
As a comparison, the stock mk1 ECU has an 8 bit MCU with some 16 bit registers.
It is clocked at 4MHz external. Even so, it can do a 'lap' of its program code in a few milliseconds. It doesn't measure 'everything' every lap but then things like the air temperature and coolant temperature and TPS don't change that quickly anyway.If you consider it takes about 16 milliseconds for the engine to do one complete 4 stroke cycle at 7500rpm
(2 engine revs) it makes you wonder why you need a 100MHz processor. As for 32bit, that must surely be OTT. Or are they going to be using DSP technology? With that level of processing power you could display on a PC how smoothly the engine was rotating through a single cycle (if the dizzy has enough sensor teeth). As for the dual tables, it may mean you can have two sets of maps that you can compare/swap between as you test the car, i.e.
"before and after tables"Re: CAMS?
JMR_AW11, (edit: can't spell your name right!)
can you fit and map and teach me how to use the latest megasquirt please?
You know FAR too much about all this to selfishly horde the knowledge! Now... take my money!
[-o<
(edit: can't spell your name right!)can you fit and map and teach me how to use the latest megasquirt please?
You know FAR too much about all this to selfishly horde the knowledge! Now.
.. take my money! [-o<Re: CAMS?
http://www.megasquirt.info/UMS.htm That's the site with the info if you want to have a look Jeremy/Andy.
Andy, Jeremy's our local guru on anything AW11 and electrical, don't think he's had the chance to play with an MS. (have you Jeremy?)
Are you still planning to market your'adapted' AW11 ECU?
Chris
Andy, Jeremy's our local guru on anything AW11 and electrical, don't think he's had the chance to play with an MS.
(have you Jeremy?)Are you still planning to market your
'adapted' AW11 ECU?Chris