Tuning larger injectors

[dlshandera]

I have an 06 lbz that I just put 24lpm injectors in approximately 27% over stock.
Im looking for some help in tuning at least a economy tune for now to start with as I currently have a major lack of time on my hands eing a single dad of a 2 year old. I understand the theory and how to adjust pulse with for the larger injectors but I don't know how those items are affected at lower rpms as I have only done tuning on stock setups. I don't want to have to spend a fortune on getting it hammered out as I will be making lots of changes in the near future but need it at least up and running good here asap as I need it again. I would appreciate some help or someone to work with that can give me a place to start and I can do the other tunes I want from their.
Truck has 4 inch exhaust , airdog 165 4g, egr delete 33" tires and modded air box, 24lpm injectors

 

[hondarider552]

You can run a stock injector tune with those baby injectors

 

[dlshandera]

That's what I'm running right now but mileage is pretty shitty when hitting around 65 to 70 in the truck and I really just want to maximize the economy as Im taking it on a a lot of long trips here very soon pulling a trailor

 

[THEFERMANATOR]

I always start my tuning by adjusting the pulsewidth tables. I ALWAYS account for latency when I do it, and have found it works pretty good. I subtract 100 from the pulse table, for that size injector I would then subtract 10%, then add the 100 back in to all the tables except for those that are supposed to be zero(this is CRUCIAL to keep the zero ones zero). Next go into your rail pressure table and ramp it up some to get your idle pressure back up to 35-40 MPA to help keep any hazing at idle out. Bring your timing up a few degrees at idle, and lower it a tad above idle(don't need much with that size injector). Are you still running stock boost tables? If so that is your biggest source of MPG gains to be had. Lower your boost down at cruise till your only holding 1-2 PSI or so, that will boost your MPG's up the most of anything.

 

[dlshandera]

thanks ferm im working on getting one put together and ill get it posted to see what you think.

 

[fastpunker]

sub'd. recently did 30 overs in my lb7 and having similar probs along with bad haze and pops on cold starts, anything below 60* ambient temps.

 

[S Phinney]

I always start my tuning by adjusting the pulsewidth tables. I ALWAYS account for latency when I do it, and have found it works pretty good. I subtract 100 from the pulse table, for that size injector I would then subtract 10%, then add the 100 back in to all the tables except for those that are supposed to be zero(this is CRUCIAL to keep the zero ones zero). Next go into your rail pressure table and ramp it up some to get your idle pressure back up to 35-40 MPA to help keep any hazing at idle out. Bring your timing up a few degrees at idle, and lower it a tad above idle(don't need much with that size injector). Are you still running stock boost tables? If so that is your biggest source of MPG gains to be had. Lower your boost down at cruise till your only holding 1-2 PSI or so, that will boost your MPG's up the most of anything.

Why subtract 100, then take 10 percent and then add the 100 back?

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[catman3126]

sub'd. recently did 30 overs in my lb7 and having similar probs along with bad haze and pops on cold starts, anything below 60* ambient temps.

hmm that's odd I gave several sets of 30's and they are about the same you can run them with a stock tune and no odd issues. I actually run them with my lb7 stock trans dsp5 and just have to cut some timing to keep it quiet. that's a about it.

 

[dlshandera]

you subtract 100 for injector latency , from the way i understand it, it is the delay in the operation of the injector opening

 

[THEFERMANATOR]

Why subtract 100, then take 10 percent and then add the 100 back?

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I found 100 to be a fairly average latency time when I did testing. It varied from around 84-99, so I called it 100 just to be safe. But every injector has a delay in the amount of time it takes from current is applied, until it actually opens, this is referred to as latency. I subtract the latency amount, then make my pulse changes, add the latency back in, this way I'm only changing the actual time the injector is flowing instead of the whole pulse time. I've done it on a few trucks with EXERGY flow sheets, and the corrected pulse times using this method normally has the pulse table dead on with the flow sheets. I tried doing just straight % changes to the tables, but found it caused some really weird anomolies at the upper and lower ends of the table. So I started figuring in latency, and the fuel rates started staying constant when I would ramp pressure up instead of fluctuating all over the place.

 

[fastpunker]

hmm that's odd I gave several sets of 30's and they are about the same you can run them with a stock tune and no odd issues. I actually run them with my lb7 stock trans dsp5 and just have to cut some timing to keep it quiet. that's a about it.

That was the result I was hoping for, but not seeming to be the case. And "TheBac" bought injectors from the same place and is having similar issues also... just chalking it up to a crappy rebuilder that doesn't know what they are doing.

Live and learn, then wear Depends :roflmao:

 

[WVRigrat05]

When I put 20 overs in mine it ran hot egt's 1000-1200 crusing on flat ground empty) until I had it tuned.

 

[dlshandera]

dsp5 tune for 24lpm injectors 27% overs

heres what I came up with for tunes so far let me know what you think goes from stock on non dsp5, eco tune , 60 ish horse, and then a 120ish and a 500rwhp tune but likes to throw a lfrp code and blows a lot of smoke working on cleaning that up

 

[Flyntodd]

I know this is old but im wondering why there was never any feedback on this tune. Hopefully bumping this will shed more light on the subject of tuning for oversized injectors for those of us no longer in the USA.

 

[Flyntodd]

Since nobody is replying here, I have calculated his stock tune (DSP1) to be about a 9% decrease in pulswidth from stock tune with stock injectors. It seems with 27% over injectors it should be a decrease of between 15-18% PW. Can anybody confirm this? It would be nice to start a new discussion with anybody tuning for larger injectors. Im trying to get a base stock tune for my LBZ that is only compensating for 60% overs. As close to stock as possible to start. Does anybody want to engage me here on this subject??

 

[S Phinney]

Are you trying to make the pulse equal to your stock injector files?


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[N2BRK]

There’s lots of info on this if you search. I suggest using the term injector latency and look for posts by TheFermanator on that topic. That is a good start.

Since nobody is replying here, I have calculated his stock tune (DSP1) to be about a 9% decrease in pulswidth from stock tune with stock injectors. It seems with 27% over injectors it should be a decrease of between 15-18% PW. Can anybody confirm this? It would be nice to start a new discussion with anybody tuning for larger injectors. Im trying to get a base stock tune for my LBZ that is only compensating for 60% overs. As close to stock as possible to start. Does anybody want to engage me here on this subject??

 

[Flyntodd]

There’s lots of info on this if you search. I suggest using the term injector latency and look for posts by TheFermanator on that topic. That is a good start.

I read all of the posts. I understand about removing 100us, then take % away from PW and then add the 100us back in. I just thought it would be fun to bring this up again to see what if any guys are doing now. Im pretty sure every topic on this forum has been discussed before. The point of this is to bounce ideas off each other and what not. I guess thats not the case here anymore.
Thanks for the replies.

 

[TheBac]

I just think most members here:


a) dont do their own tuning (me -- never understood all the parameters)
b) tune but dont want to disclose how they go about it (most tuning businesses)


But I would try to bend Mark Broviak's ear a bit. He's usually pretty forthcoming on tuning theory, when he has the time to discuss it.


IMO....and remember Im no tuner....pulse and timing changes are not linear in regard to % different injectors. There's so much involved beyond just the larger injector tips....CP3 health, fuel quantity available (do you need 2 CP3s?), injector health, etc

 

[PureHybrid]

I read all of the posts. I understand about removing 100us, then take % away from PW and then add the 100us back in. I just thought it would be fun to bring this up again to see what if any guys are doing now. Im pretty sure every topic on this forum has been discussed before. The point of this is to bounce ideas off each other and what not. I guess thats not the case here anymore.
Thanks for the replies.

I've never tuned a LARGE injector, but once you get the pulse dialed back in the idle areas to get the mm3 close to stock and your max pulse set to where you want just blend it all in. If you have drivability / smoke problems from there, start tweaking more. A flow sheet will help also to get started.