Performance enhancement by turning cam pulley?

Sonix · **Posted:** Sun Dec 14, 2008 5:01 pm

Something I'm just curios about ...
While I was re-assembling my engine this week, I was thinking about how they increase a petrol engine's performance, by turning the cam pulley one tooth faster (causing the intake valve to open a LITTLE bit faster, so that more air is sucked in for the stroke)...
Will it have any effect on the CRD, if I do the same thing on the intake cam pulley?? (turning the pulley one tooth faster than normal timing setting) ??

BlackLibertyCRD · **Posted:** Sun Dec 14, 2008 5:16 pm

You probably suck some exhaust and have your own built in egr system. Will definably hurt performance.

gmctd · **Posted:** Sun Dec 14, 2008 5:16 pm

That's done because the fuel charge is trucked in with the air charge on the intake stroke on them other motors - Diesels get a full load of air on each intake stroke - fuel is injected at the top of the compression stroke, long afer the intake stroke has vacated the premises - wanna incease fuel\air ratio, just push harder on the go pedal - also, we got a magic puffer on the intake, blows as much more air into the cylinders as anyone could wish for - add fuel to suit - so, no, no improvement

MrMopar64 · **Posted:** Sun Dec 14, 2008 7:24 pm

Because of the cam profile on these engines and the tight quench area at TDC, even the slightest bit of off-timing can result in a collision.

Additionally, it will cause the engine to not start since the engine will not see the proper cam shaft pattern from the sensor in time with the crank sensor gap and won't allow the engine to "synchronize" in the software.

BlackLibertyCRD · **Posted:** Sun Dec 14, 2008 10:19 pm

Hey, what MrMopar says!!!! Like I really know.

I'm sure you been through enough with broker rockers.

mackruss · **Posted:** Mon Dec 15, 2008 2:52 am

Stick to the basics and research some chip tuning instead.

Sonix · **Posted:** Mon Dec 15, 2008 9:25 am

ok ...thanx for the info ...pretty much what I thought from the start, else I guess I would've read about it LOOOOng ago on the forums .. :wink:

gmctd · **Posted:** Mon Dec 15, 2008 11:55 am

In turbocharged Diesel engines, the intake valve can be opened when the exhaust valve is still open, such that the turbocharger will clear the cylinder of previous combustion residuals, ensuring each new cycle will start with totally fresh air charge, making more power and greater efficiency - it is seldom done anymore because of potentially increased oxides of noxious (three guesses how this relates to EGR), but it takes some precision cam timing\grinding to do this - simple shade-tree alteration of mechanical timing-set can get you into big trouble, as indicated by calibration engineer - read Sonix's post on 'loose cam gears' to get a sense of catastrophical results when cam sprockets slip a tooth or so

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=37384

gmctd · **Posted:** Mon Dec 15, 2008 12:34 pm

Need specific info, Mackruss - what scanner software allows alteration and ECM reflash?

Trigger phrase being:
"The reason i ask is because apparantly if you change settings you cannot go back and change them to what they previously were"

Only reason DRBIII and Starscan cannot reflash to previous levels is that previous versions of flashware are destroyed under watchful eye of DCJ Service Manager, as directed by TSB.

mackruss · **Posted:** Mon Dec 15, 2008 4:30 pm

gmctd wrote:

Need specific info, Mackruss - what scanner software allows alteration and ECM reflash?

Trigger phrase being:
"The reason i ask is because apparantly if you change settings you cannot go back and change them to what they previously were"

Only reason DRBIII and Starscan cannot reflash to previous levels is that previous versions of flashware are destroyed under watchful eye of DCJ Service Manager, as directed by TSB.

I'll find out tomorrow and post some info when done, if done. What do you mean with regards to the flashware?

gmctd · **Posted:** Mon Dec 15, 2008 10:06 pm

I was using flashware to mean the operating system loaded into flash memory, as opposed to the unchangeable bios loaded into rom, or the variable operating parameters shuffled into ram - F37 was responsible for a 'bad' reflash, overwriting the previous not-so-bad-as-F37 reflash, which was used to overwrite the previous version, etc, etc, ad infinitum

mackruss · **Posted:** Tue Dec 16, 2008 12:35 pm

gmctd wrote:

Need specific info, Mackruss - what scanner software allows alteration and ECM reflash?

Trigger phrase being:
"The reason i ask is because apparantly if you change settings you cannot go back and change them to what they previously were"

Only reason DRBIII and Starscan cannot reflash to previous levels is that previous versions of flashware are destroyed under watchful eye of DCJ Service Manager, as directed by TSB.

What is the process when chip tuning, adjusting within the EPROM

gmctd · **Posted:** Tue Dec 16, 2008 3:18 pm

No - your communication\programming\flash device would upload the original program from flash memory in the computer module - then you would save it, make a copy, edit parameters'n'stuff in the copy with an editor\compiler specific to the language used in the mcu device and save it - then you would reflash the computer with that revised program - but, you have to know what parameters are stored in any particular memory area, and which code-lines can be altered or revised - but, DCJ ain't gonna provide ya with a memory map with specific definitions for measurement, control, and response, and instructions for alteration - which, btw, is prohibited by law

You can program and upload data from a rom, prom, eprom, but you cannot remove and replace any stored information in those - the eprom can be erased and reprogrammed, usually requiring removal from the control module circuitry for the process - an eearom is electrically programmable, erased, and altered, but still not as versatile as flash memory

The mcu is a Motorola MC68HC11\deriv, and the specific Motorola programming language can be found all over the 'net and most universities and libraries, and in Motorola spec books - M sold off their solid state division somewhere around Y2K to concentrate on communications hardware, such as 2-way radios and cell-phones, but those mcu's and derivatives are still produced and available from the "new" owners

If you have a background in mpu programming, and are a fairly accomplished programmer, it should be no hill to assimilate the Motorola stuff - even then it will be difficult to modify the CRD ECM, as DCJ and Bosch provide no mapping for your convenience - you will need to determine modules, routines, subroutines, everything from scratch - may be an easier task if very familiar with MC68HC11 language, which would allow comparing software in US and Euro ECM's, and manual trans ECM's to auto trans Ecm's to determine software module mapping

'Nuther words, buying a reflash tool and some software does not magically endow the expertise required to understand and modify CRD ECM software - but, having a spare ECM will allow you to practice - harmlessly or harmfully is up to you

MrMopar64 · **Posted:** Tue Dec 16, 2008 6:34 pm

Unfortunately, there is a little bit of a snag: when the software is compiled into the format used to flash with the dealer scan tool, it check the current part number in the module and compares it to that in the new calibration. If the new flash supercedes the old calibration (as it should), then the flash proceeds as normal. However, if you try to flash an older cal over a newer one, it won't work.

So, in a nutshell: if you already have the latest, you can't flash an older cal over the newer one.

gmctd · **Posted:** Tue Dec 16, 2008 10:03 pm

Agreed - but the aftermarket reflashers don't have that fatal flaw, thus can reflash anything to any revision - prollem is getting an earlier revision, and knowing which revisions are the good ones

mackruss · **Posted:** Thu Dec 18, 2008 10:03 am

Well we had the scan running today and did some testing one of which happened to be an emission test and passed and that's with a blocked EGR and no CAT with 50 ppm diesel not that i'm tested anyway.

We now waiting for the protocol from the software manufacturer and then we'll start with the tuning, we did notice that the turbo boost was set lowish and can be tweaked but we'll do one parameter at a time so we know where we heading.

Perhaps someone can e -mail me a remap to save me time :wink:

Performance enhancement by turning cam pulley?

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