Slight side note this one, not sure if its welcome in this topic or not, so have done as a seperate post.


WHY ARE ALL CHIPS THAT YOU CAN BUY "OFF THE SHELF" NEVER EVER REALLY ANY GOOD?

Ok, so looking backat my previous post, you can see that cam timing is critical thing that effects the VE of an engine, and obviously we all know that CR plays a big part in determining how much ignition advance an engine can take in order to avoid the PCP being at the wrong time.

So lets apply that bit of logic to off the shelf chips and fitting them to an engine.

How is an off the shelf chip made?
Well fundamentally, they are made in exactly the same was as the live mapped chips we are talking about here, a tuner takes their given "mule motor" for testing, puts a certain spec of parts on it (or possibly uses a customer car of the correct spec) and they map a set of chips for it.

Then what?

Well, then they take account of the points i just made about cam timing and CR, as these are the two things that vary most from engine to engine (skimming a head for example is common practice and effects BOTH cr and cam timing)
So what do they do to "take account" of potential differences?

Well they aim safe, VERY fooking safe, after all whats going to ruin your reputation more, someone making 10bhp less than they could have done, or someone blowing their engine up?

So how do they "aim safe" with the chips?
Easy, they delibertely go through and richen the chip up, so that it runs more fuel than is needed, so that if your injectors are slightly down on flow, or your regulator isnt quite adjusted correctly, it will still avoid that leanout that can kill your engine.
Same for the timing, they take their nice "3 degrees from det" or whatever it is basemap and they take a HUGE chunk of timing off of it, like literally as much as half a dozen degrees in some cases!
This means if your CR is too high (4wd head on a 2wd bottom end or whatever) you still have some sort of hope of keeping your engine in one piece!


How well will it work on MY engine?
Well, the answer is (compared to a live map) probably not very well at all in reality!
But it should be nice and safe, and due to the increase in boost on a stage 3 chip or similar, you should get a good increase in power, but my god will you notice the difference when you get a live map (or custom chip) instead!

Are some better than others?
Yes, some tuners (Stu@MSD) for example, will ask a lot of questions about your car, and select a chip that better suits it so that it doesnt have to be too far in the safe direction, but its still always going to be that little bit safe no matter how much detail you give him, as he isnt going to want to kill your engine just cause you didnt know the head has been skimmed after all, so he will ALWAYS assume you are mistaken at least a little bit with what you tell him!

Why should i have my chip setup by a tuner?
Well see above basically, if you go to someone like stu, they can fit the chip, give it a go, and if its detting its tits off cause you happen to have an engine fitted with N/A pistons by mistake then at least it will get noticed before its too late, and you can either by a slightly different chip, or not buy one at all until your engine fault is corrected, same for if the fuel pump isnt up the job (or more usually the wiring) or the fuel pressure is wrong or whatever.




Thats a bit off topic though, so feel free to move to another topic "Off the shelf chips, why arent they the optimum" or something like that if you want.