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Old 24th April 2008, 09:40   #46
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I understood the point of preignition where the first time the injector is fired after BDC to reduce the diesel knock and make the engine run smoother but at the same time have also read that the injectors are fired upto 5 times per cycle depending on the fuelling requirements.

This would mean that the pulse duration into the number of times the injectors are fired would be the total pulse duration on each cycle. This would limit the rpms achievable by the engine.Which is what brought me to the conclusion of using larger injectors with the correct ecu could help solve the problem of additional boost and rpms.

This would logically be easier to do on a traditional turbo diesel where one could increase fuelling referenced to boost on the mechanical pump.

Karthik it is about time you came on to this thread and tried to clear up any wrong info put up including by me so that we do not go off on a wrong tangent. Direct injection is a completely new thing for us to understand so easily, please help.

Last edited by Psycho : 24th April 2008 at 09:50. Reason: I hate opera mini as it trims my posts down and I need to rewrite them again.
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Old 24th April 2008, 10:02   #47
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That to is made for reduction of noise as just one perinjection did not get the noise down enough to compete with the petrols, the side effect of that is it looks like a big pulse width,the 5 preinjections are hardwared in the latest systems these do not vary according to the fuel requirement only the final injection pulse varies,that is if a system is designed with 3 preinjection pulses than it will give 3 pre injections from lowest to the highest rpm [through out the rev range] same is the case with 5 preinjection [the only excemption can be that if the engine temperature is high enough the preinjection can be reduced, but I am not sure about this].5 pre injectionssystems are seen only in really expansive cars [read merc,beemeers,etc] not the cheap common rails, swift,dicors,etc.these make do with put 3 injections.
Also higher number of preinjections means that the cylinder remains hot for longer duration, this help the diesel burn more efficiently.As these are used when the piston is moving towards the TDC, and not at the TDC.
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Old 24th April 2008, 10:33   #48
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not the cheap common rails, swift,dicors,etc.these make do with put 3 injections.
I know you didnt mean it that way and it was just a comparative term but in no way was the DDiS cheap. Cost us all of 6 Lakhs !! Lol.
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Old 24th April 2008, 11:09   #49
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The systems in these cars are a generation older than the once on the imports, the cars are not cheap in any sense and on even down on quality.Only thing is the ECMs and the injectors are cheaper than those on the cars with 5 preinjection Thats all, the systems on these cars are better than the one on the Laura [Pump Duse] VW is using the new common rails on their new models.
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Old 24th April 2008, 12:41   #50
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Hey Dinar that's some good info there. Have you been working with CRDIs and if so would love hear more on this topic.

It makes more sense now about the last pulse being the main pulse for the required fuelling. It gives us more opportunities on understanding on how to work around the ecus much better.

Ps: so this does mean gradually increasing the fuel pressure on the rail while referencing it to boost would definitely help in incresing fuel flow and more power from the engine.
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Old 24th April 2008, 14:25   #51
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Originally Posted by DocG View Post
by convert if you mean swap out a FGT for a VGT yes
If you mean modify a FGT into a VGT then no
that too needs lot of modifications. installing EGR, or pressure sensor on intake manifold, etc.
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Old 24th April 2008, 17:03   #52
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Increasing the pressure on the rail helps in such a way that higher pressure, of diesel is injection atomizes the fuel better , and also the simple rule that higher pressure means more quantity of fuel [this is very small increase].
Diesels usually work well with higher pressure ,higher fuel pressure mean finer atomization [simple comparison between DI and IDI systems]and hence efficient burning. In common rail thou the pressure is constant through out the range, increasing the pressure by even few bars in the system will give big benefits. case with swift diesel with peggy back, only care has to be taken while doing this is the pressure should be kept in check, since the pumps in mechanical there is a chance of over pressure which can harm the pump,rail,injector and other plumbing.
In mechanical systems one can increase the pressure but the benefits are not that much in small engine. In larger engine like the cummins with mechanical pump one can increase the bhp torque and also peak rpm of the engine by changing couple of spring on the pump.
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Old 25th April 2008, 10:00   #53
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Keshav - Preinjection is primarily a refinement factor and most lower end CRDI cars do away with 2 to 3 preinjections, completed in 8-12 deg of crank rotations at idle and merges into 1 or 2 injections as the revs go high.

We are testing max flow capabilities of OE injectors so you can expect that data soon.

Increasing fuel pressure to increase fuelling with ability to adjust with respect to boost, driving style, etc should be fun !!

And dude, guys like you should be busy tuning and not worry about lower level details like these
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Old 25th April 2008, 11:44   #54
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Originally Posted by rdkarthik View Post
And dude, guys like you should be busy tuning and not worry about lower level details like these
Hey Karthik,

How do you expect someone to tune without knowing the basics of how an engine operates and what are the limits to where one can push it. I would at no point want to go beyond recommended capabilities of an engine.

Simple things like max flow data is a boon in cases where we do not have data even available online.

Look forward to more info on this .
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Old 26th April 2008, 01:10   #55
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Keeping in mind a few constants:-

4. Not willing to modify internals like lighter cams, forged internals, except for a clutch as i feel the Swift has a weak clutch.

Now for the queries:-

...those who are tight on budget and looking for soft mods to their diesel Swifts.
Guys that was some good amount of knowledge shared on fuel management but in the process we deviated from the topic and above mention points i.e these modifications would ofcourse require a good amount of money to be spent and only seem feasable once a driver has extracted full potential of the car through other basic and simpler mods(Pete's, CAI, FFE etc etc)and ofcourse one's own capabilities to the extent when a driver would feel that the car has nothing more to offer and now heavier mods are required hence forraying into mods including internals, fuel management, bigger turbo etc.
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Old 26th April 2008, 01:23   #56
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So comming back to the topic
Pete's 2nd and 3rd stage can be activated with the car still stock or the stages are in accordance with the state of mods on the car?
In short is it driver prefference to activate these stages or state of mods on the car?
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Old 26th April 2008, 06:50   #57
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Quote:
Originally Posted by abhik View Post
So comming back to the topic
Pete's 2nd and 3rd stage can be activated with the car still stock or the stages are in accordance with the state of mods on the car?
In short is it driver prefference to activate these stages or state of mods on the car?
yes it is driver preference. other than the tuning box, all you need is the CAI. even that is not necessary, but having the CAI does significantly reduce smoke and improves high end too.

actually abhik-
the topic is souping up the DDiS, not pete's box for the DDiS, but hey! its your thread
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Old 26th April 2008, 14:42   #58
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Hmmm I was looking at the CAI to maybe spruce up the initial lag a bit.
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Old 26th April 2008, 21:51   #59
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Quote:
Originally Posted by abhik View Post
So comming back to the topic
Pete's 2nd and 3rd stage can be activated with the car still stock or the stages are in accordance with the state of mods on the car?
In short is it driver prefference to activate these stages or state of mods on the car?
The stage 2 will work fine with stock filters and every thing, but stage 3 requires universal filter as the system runs rich at top end, the car smoke due to this. there will be carbon deposits if it smokes too much...
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Old 26th April 2008, 22:48   #60
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Originally Posted by rippergeo View Post
actually abhik-
the topic is souping up the DDiS, not pete's box for the DDiS, but hey! its your thread
Sorry bro but was a little confused about the box and its requirements and was related to the topic so i thought i could push in a Pete's query aswell

Last edited by abhik : 26th April 2008 at 22:49.
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