[rdkarthik]

Originally Posted by veyron1

Ok. Here goes. Speed/density metering or mapping is usually dependent on engine speed, air density and MAP.

Alpha-n is the advanced version for mapping which can take in more radical cam profiles because it reads from the engine RPM and throttle body positioning only, bypassing the MAP.

Alpha-N is not an advanced version for mapping. Its just an alternative. It works great on wild cam profiles because these cams produce a lot of pressure fluctuations in the intake manifold when they are working at RPMs other than designed for, confusing the speed-density system.

Now, both systems/routings are prone to vacuum errors/stats.

What errors are you talking about? Is it computed quantity of air in the system?

Alpha-N does not depend on vacuum anyway...

The Escorts had TBIs. How exactly did the alpha-n system "improve" the combustion characterisitics? AFAIK, MPFI's have much more precise fuel metering, correct?

right.. MPFIs are far better than TBI for precision and metering.. MPFIs can be Alpha-N too.

wrt escorts, when compared to a carb system, alpha-N TBI is definetly an improvement, but not wrt mpfi and/or speed-speed density ssytem for a stock car.

Ok. Now for details. Let's have in detail the effects on cam profiles for alpha-n (since that's what's used for racing applications- we know that poppet and stem height are in direct relation to lift; so we'll go into that later),and ignition timing (both ignitor mapping and delco alteration-for the Escort). And how exactly do both of them alter IPW at WOT (assuming WOT is at 100%, both systems are giving 100% fuel flow)....

i thought the escort had a distributorless setup...

Simply put, let's have in detail the differences in ACTUAL practical applications, and how-to's...

1. With Alpha-N its very difficult to pass emission standards, even at OEM levels - E2,E3,E4,etc, as compared to speed-density or maf. Thats why we dont see them on street cars (execpt in limp home mode with a screwed map sensor system)

2. Alpha-N is prefered (actually a must) for individual throttle body and/or wild cam profile applications.

3. MAP or MAF is a must for turbo/supercharger applications

waiting for the guys to chip in.......

[chetanhanda]

Originally Posted by veyron1

Ok. Here goes. Speed/density metering or mapping is usually dependent on engine speed, air density and MAP.

speed density uses 3 things - vacum readings from MAP , RPM and AFR IPW is then looked up for values of x,y and z..
didnt understand where you got air density and MAP as 2 diff params...?

Alpha-n uses TPS and RPM and provides the corresponding IPW

Originally Posted by veyron1

Alpha-n is the advanced version for mapping which can take in more radical cam profiles because it reads from the engine RPM and throttle body positioning only.

I wouldn't call Alpha-n as the advanced version for mapping..
it simply makes the mapping more simple and less complex, I would call it a more crude way of metering my fuel.. e.g it doesn't bother abt IAT,isnt very sensitive to slight TP and pretty much useless for forced induction applications as I need the ECU to calulate precise boost.. coz TP wouldnt directly be proportional to the air being sucked in

Usage - [1]Only if the radical cam profile is causing pulses in the intake to such an extent that the MAP is unable to provide an accurate resolution due to fluctuations
[2] OR if I am using ITB ... getting MAP to work will be a tough one with 1 map sensor per runner

Originally Posted by veyron1

bypassing the MAP.
Now, both systems/routings are prone to vacuum errors/stats.

Only if you go in for a customised hybrid system using both alpha-n and MAP.. Atleast I dont know of any application using both ..Ive heard MAP or MAF or alpha-n controlled sytems but not combination of all 3..

Originally Posted by veyron1

The Escorts had TBIs. How exactly did the alpha-n system "improve" the combustion characterisitics? AFAIK, MPFI's have much more precise fuel metering, correct?

Ford Escort had a primitive 50 BHP engine, it used alpha-n becoz it was simpler not becoz the cam was so lumpy that a MAP would have failed to get a steady reading.. due to changes in vacum on every intake cycle..
Also as you have mentioned it had a TBI ..so Im guessing the alpha-n would have been easier to implement....

Originally Posted by veyron1

Ok. Now for details. Let's have in detail the effects on cam profiles for alpha-n (since that's what's used for racing applications-

CAM profile wont directly affect the choice of alpha-n over MAP.
If we dont have constraint on the length of the intake runners we can even out the intake pulses to an extent... and even use crazy overlapping cams and use MAP, without having to move to alpha-n
And I feel ITB would also be a bigger reason to move to alpha-n.

Originally Posted by veyron1

we know that poppet and stem height are in direct relation to lift; so we'll go into that later)

are u talking in context of valves which dont use springs ? something like used on ducatti .. desmodromic? they dont use springs coz they dont cause valve float...
(This is OT are u from the biker background ..becoz AFAIK we use stiffer valve springs if we are planning to rev higher than stock spec..)

Originally Posted by veyron1

and ignition timing (both ignitor mapping and delco alteration-for the Escort). And how exactly do both of them alter IPW at WOT (assuming WOT is at 100%, both systems are giving 100% fuel flow)....

IPW at WOT for MAP is not altered.. the ECU simply goes into open loop at WOT for a MAP.. I dont think the ECU alters the IPW when it goes into WOT.. it simply loads a diff MAP.. only under part throttle it will try to provide diff IPW's
regarding alpha-n - I dont know coz I havent seen any fuel/ignition maps of cars running alpha-n sytems..

[chetanhanda]

Originally Posted by rdkarthik

Alpha-N is not an advanced version for mapping. Its just an alternative. It works great on wild cam profiles because these cams produce a lot of pressure fluctuations in the intake manifold when they are working at RPMs other than designed for, confusing the speed-density system.

.. we can minimise the pulses to a certain extent only by tuning the length of the intake runner but again we have restrictions as to how much we can compensate by doing this ... alpha-n is the next best soln

Originally Posted by rdkarthik

What errors are you talking about? Is it computed quantity of air in the system?

Alpha-N does not depend on vacuum anyway...

right.. MPFIs are far better than TBI for precision and metering.. MPFIs can be Alpha-N too.

wrt escorts, when compared to a carb system, alpha-N TBI is definetly an improvement, but not wrt mpfi and/or speed-speed density ssytem for a stock car.

Originally Posted by rdkarthik

1. With Alpha-N its very difficult to pass emission standards, even at OEM levels - E2,E3,E4,etc, as compared to speed-density or maf. Thats why we dont see them on street cars (execpt in limp home mode with a screwed map sensor system)

yes dude and these alpha-n systems dont consider target AFR at all like speed density systems ..base maps simply say x rpm and y TP = IPW in simple words..

Originally Posted by rdkarthik

2. Alpha-N is prefered (actually a must) for individual throttle body and/or wild cam profile applications.

3. MAP or MAF is a must for turbo/supercharger applications

[Ford Rocam]

Alpha-n As the name implies is alternative method for metering fuel by using throttle position sensor in the column index in a fuel table thus name "Alpha-n" after throttle angle = (alpha) & engine speed = (n).

why its preferred to use for tuning with I.T.B? cause Map sensor (or speed density) will never be able to provide air pressure signal with respect to actual air entering the engine because of specific characteristics of I.T.B hence if using Map for I.T.B it will not be able to value fuel correctly & it will be very sensitive to small changes & can become very lean with change in elevation or ambient air pressure.

just my 2 cents...

[Deepz]

Originally Posted by mclaren1885

Get headers calculated accordingly. Get a cam that gives you the kick in this range.

Hi McLaren,thanks for the info..If any furthur suggestions to do the same please let me know..Thanks again..

[veyron1]

Originally Posted by chetanhanda

speed density uses 3 things - vacum readings from MAP , RPM and AFR IPW is then looked up for values of x,y and z..
didnt understand where you got air density and MAP as 2 diff params...?

MAP is Hg. Pressure. Air density is read as temperature. IAT. Hence the mentioning as different parameters. But how is AFR IPW taken as one? IPW is computed from others for appropriate AFR, correct?

Originally Posted by chetanhanda

wouldn't call Alpha-n as the advanced version for mapping..

Originally Posted by rdkarthik

Alpha-N is not an advanced version for mapping. Its just an alternative.....

Ah. Ok. That clears a lot.

Originally Posted by Ford Rocam

Alpha-n As the name implies is alternative method for metering fuel by using...

Superb. Exact practical use explanation.

Originally Posted by rdkarthik

What errors are you talking about? Is it computed quantity of air in the system?

Right. But I'm still not quite sure we're on the same track here. By computed quantity, you mean the actual or residual values for intake at the ECM end for calculating IPW, correct?

Originally Posted by chetanhanda

Usage - [1]Only if the radical cam profile is causing pulses in the intake to such an extent that the MAP is unable to provide an accurate resolution due to fluctuations
[2] OR if I am using ITB ... getting MAP to work will be a tough one with 1 map sensor per runner

Originally Posted by rdkarthik

2. Alpha-N is prefered (actually a must) for individual throttle body and/or wild cam profile applications.

Neat. So here's a doozie. What happens for TC/SC applications, where we have to monitor boost as well via MAF (if we try to use ITB as well, that is) ? ITB's and aplha-n mappings are great for N.A, but does it or can it actually make a marked improvement for boost applications?

Originally Posted by rdkarthik

i thought the escort had a distributorless setup...

Nope. No digital ignition/DDLi for the Fords. Camshaft run delco at right end of valve cover. Which was why I wondered about the alteration specifics.

Originally Posted by chetanhanda

are u talking in context of valves which dont use springs ? something like used on ducatti .. desmodromic? they dont use springs coz they dont cause valve float...
(This is OT are u from the biker background ..becoz AFAIK we use stiffer valve springs if we are planning to rev higher than stock spec..)

No, I was talking about ordinary valves, not the desmosedici/desmodronic setup. But let's get into that after the mapping is a bit clearer. (LOL....I'm not from a biker background per se...I prefer cars as well...ever so slightly...)

Great stuff so far....things are getting much clearer...especially for learners like me....

[rdkarthik]

Originally Posted by veyron1

MAP is Hg. Pressure. Air density is read as temperature. IAT. Hence the mentioning as different parameters. But how is AFR IPW taken as one? IPW is computed from others for appropriate AFR, correct?

IPW is computed from a lot of parameters , including target AFR and feedback from existing AFR(for closed loop only).

To make it simple, speed = RPM, density = manifold pressure (as you said), but air temp, engine temp, altitude, AFR,VE,etc come in as correction factors..

Right. But I'm still not quite sure we're on the same track here. By computed quantity, you mean the actual or residual values for intake at the ECM end for calculating IPW, correct?

I am lost too ... I was referring to errors you mentioned regarding vacuum..well, computed quantity is residual exhaust/overlapped charge + fresh charge with all corrections in place..

Neat. So here's a doozie. What happens for TC/SC applications, where we have to monitor boost as well via MAF (if we try to use ITB as well, that is) ? ITB's and aplha-n mappings are great for N.A, but does it or can it actually make a marked improvement for boost applications?

In cases of TC/SC with ITB, you will have to go map way. I am guessing it should be okay ( still wondering why you would want a boosted ITB ) as pressure pulses would be dampened due to common intake chamber....
Mapping with ITB, Alpha-N and TC/SC will be difficult (never precise) ,but should be able to get away with atleast for WOT..

Nope. No digital ignition/DDLi for the Fords. Camshaft run delco at right end of valve cover. Which was why I wondered about the alteration specifics.

i'm not sure abt this, but i vaguely remember playing with ignition on a 1.6 zetec escort (or was it astra??).. it was a 3 wire twin coil wasted spark system...let me chk on this..... most fords have DDI though....

Great stuff so far....things are getting much clearer...especially for learners like me....

We are all learning too .........

[vezj420]

Karthik, Fords (even the ones here) use a 4-tower ignition coil. Not sure about the Escort though.

I have a slightly off-topic question for you (and sorry if u've already answered it before):

What do u (Race Dynamics) use to read the ECU Maps of the cars u work on?

[rdkarthik]

Originally Posted by vezj420

Karthik, Fords (even the ones here) use a 4-tower ignition coil. Not sure about the Escort though.

I have a slightly off-topic question for you (and sorry if u've already answered it before):

What do u (Race Dynamics) use to read the ECU Maps of the cars u work on?

Well, on the fords its essentially twin coils bundled into a single package, that ends up looking like 4 tower ignition coil ...

We dont read any maps off the original ECUs at all.... We build all our maps ( and all its associated correction and setup parameters ) from scratch. ...

[speed0mania]

hey guys ! i have a doubt regarding how the 1/4 times for my car will be affected if i get a custom ffe with headers for low-mid range for my swift! i know this would shift the power band lower and not increase power in total, but apart from the launch rpm getting lower would it bring down the overall 1/4 mile time?

p.s. this is just a doubt that popped up! i know team bhp doesn't supprot illegal street racing in any way!

[veyron1]

@speedomania; You'd get better 60-feet timings. Provided you have good traction. After that, it's all about the top end. Low/mid range mods are good for in city driving. Could actually give you better F.E, if driven properly.

[speed0mania]

thats what i want it for basically! better city daily driving! but i dont really want to miss out on the kick the swift gives @4.5k rpm ! (rare times i get to that) ! i know it can give me better FE but dont think ill be getting any with the type of revving ill be upto with a FFE!
now im confused bout what to get!

[streetsdisciple]

Learnt allot from reading this thread , good job everyone who helped to clear out the misconceptions about performance mods.

one question - what are Piggy Back Chips ?? how much do they cost ??
am asking this coz i read in someone`s garage here that it increased the output by 15-18 bhp.!

[vezj420]

Originally Posted by rdkarthik

We dont read any maps off the original ECUs at all.... We build all our maps ( and all its associated correction and setup parameters ) from scratch. ...

Karthik, that's what I meant!! I know u guys build the maps from scratch, buuut, don't u think it would be beneficial if u could read the map and THEN alter the values? (rather than trial & error from the start) I'm asking because I know a division in my company that uses these map scanners. Do u think they would help u?

what are Piggy Back Chips ?? how much do they cost ??
SD, piggy back chips are chips/modules that latch onto your existing ECU (hence the name) to read and alter the existing maps for ignition, fuel timings, etc. The problem with them is, you have to get ones that are compatible with your car's ECU or are at least retunable, otherwise it's a big waste of money. Expect to pay between Rs. 20k and 40k for a basic to mid-range solution, in India as well as imported. Pete's Performance has a few in stock for a few cars here....

[Deepz]

Someone once told me the following statement- "dude try this, put some naptholene(not sure about spelling) ball s near the air filter, your petrol will become high octane fuel". I told him not to mention this near a fuel station, the attendants will beat you for letting out their secret.