Team-BHP - FAQ for tuning fuel injected cars - Step by step virtual buildup!

I am sure a lot of people on this forum know what's involved in tuning a fuel-injection system (bigger injectors, ecu remap etc) after adding some bolt-ons like headers, cam etc or porting the head.

But then there are people like me who would rather use carbs because they dont know enough about (or are even scared of) tuning the fuel injection system. For example, for our G13B Esteem build, we used Weber DCOEs even though we have a 16 valve head meant for fuel injection. Know what I mean?

So why dont we all make this an FAQ where everyone will pitch in with what they used or what they have seen being used (Facts only, no opinions!). We could start off the discussion with general stuff and then move into model-specific stuff. Lets have it.....

Ananth

U need to get ur maps right. If not, U mite run too lean or too rich.
While rich is not bad for the engine,but for the environment.
Running too lean is certainly bad for the motor because it overheats the internals.
Remapping in India is not just happening much because of the lack of a chassis dyno which is very much needed. A dyno can even help prove the efficiency of even a free-flow filter which is very much in doubt today.

ananth this post sounds like a nice idea, we can tune a virtual fuel injected system on this post say a typical 4cylinder, OBD2,16 valve,DOHC without VVTI,Vtec or MIVEC type of system to keep things less complicated.

guys how does this sound like ? just a quick overview..
we can add more technical details to every step

1] increase amt of mixture by aggressive cams, increase throttle body size,air intake plenum,CAI, increase fuel by high pressure pump.
increase the flow of gas out of system with header,freeflow

2] Adjust the fuelling 1st: adjust fuel by AFC or standalone sytem or remap ECU with crome etc..
get the fuelling right, monitor AFR and EGT to make sure u are not going lean or rich and heating the engine up while lean.

3] After nailing the fueling right go after the ignition remap, increase the ignition timing, this is where the ECU or standalone system is reqd.
stock ignition sytem may have to upgraded to a bigger capacity one to handle the extra load and the extra prgrammability reqd..

4] then go for fuel again and make sure ur injectors are not maxing out, then back to ignition timing..

All of the fuel and ignition maps to be done ideally on a loading type dyno to get the values at appropriate rpms.

just to summarize..mod fuel map 1st ,then timing map:
main aim would be to pump more fuel thru the engine keeping the AFR and EGT right, basically pump more fuel based on ur MAP/MAF sensors which tell u how much air your engine is taking in...and igniting it correctly by altering ur ignition timing maps..

ok we are off to a decent start. ideally we would be doing what Chethan proposed, tuning a virtual injection system.

Let me make my questions simpler but more specific. Please feel free to add ANY information (like the snippet that mcLaren posted) you may think is useful.

Lets say you have a 16-valve G13 B esteem engine that is fuel injected. Assume you are me and dont have a clue as to how to tune the computer-related stuff.

You already did the following:

1) Added a BP320 competition piper camshaft.

2) ported the intake/exhaust ports and gave the valves a 3-angle cut.

3) shaved the head and are running 10.0 CR

4) added headers

5) added individual throttle bodies (one per cylinder) with a tuned length manifold.

Now, what do you need to do, in terms of specific equipment required to get the fueling and the timing (most importantly) right? Mainly, what kind of tools are required (other than a dyno of course) ? What do you plug your laptop into (thats the only thing i know about fuel injection tuning: you plug in your computer, change some values like you do in NFS, and off you go!!!)?

Quote:

Originally Posted by ananthkamath (Post 404576)

ok we are off to a decent start. ideally we would be doing what Chethan proposed, tuning a virtual injection system.
Let me make my questions simpler but more specific.

5) added individual throttle bodies (one per cylinder) with a tuned length manifold.

:)
hey ananth can we make it single throttlebody connected to a single
intake plenum with indiv runners to each cylinder.
so that we can have 1 MAP sensor and 1 TPS for the throttle body and 1 injector per runner.
suggesting this for our virtual tuning system becoz this setup is very common on typical 4cyl,16v EFI's

Quote:

Originally Posted by chetanhanda (Post 404590)

Yes but if you're looking at that sort of insane performance and ultra-high flow ITBs would certainly help.

Quote:

Originally Posted by v1p3r (Post 404588)

Ignition I can't say, but an easier way to get more fuel is to use higher flow-rate injectors. For the same pulsewidth, they will deliver more fuel.

Ananth, who is this friend? We've been hearing rumours of dynos for years.

Yes but as you will be pumping more fuel and are having modified cam lift,duration and overlap...
as we are trying to pump more air thru the engine we will be running higher RPMS, so we will need to advance the spark x-y degrees BTDC as the speed increases (x is the stock no of degrees). so the ignition map has to be modified if ur are using more fuel/modding base fuel map.

every cylinder has "peak cylinder pressure at which it makes the max power.the spark has to be initiated at the correct time. but this time varies,because a cylinder charge takes n seconds to combust and as the engine speed varies(increases from stock), this time also varies..i.e reduces.. so corresponding the y degrees must be advanced ...i.e is our ignition advance curve.

Quote:

Originally Posted by v1p3r (Post 404595)

Yes but if you're looking at that sort of insane performance and ultra-high flow ITBs would certainly help.

yep!! right on dude..
but we are trying to do a basic 32bit EFI 4 cyl engine.. we are not considering superchargers,quad turbos or NOS.
ITB would definately help but then we would need to reconsider our basic inatake plenum design . runners and fuel rail design...we are trying to do a basic bone stock virtual engine