my injectors are too big

[americasfuture2k]

im running some of the L67 injectors and the tuner is having trouble tuning the engine since he cant get the milisec low enough for idle. he said some 24lb injectors would be sufficient. what are my options for some 24lb injectors? he said hes used mustang injectors for the LS1s in his tuning and build adventures.

[1988GTU]

I am by no means a pro at tuning, but I do know it is possible to tune for bigger injectors. It's not like you are using something super duper big.

Whom ever is the tuner is not doing there homework. It is very possible, they just seem like they want to make a quick buck and bang you out in an hour or so. Don't pay them a dime until you are fully tuned and not hacked up with extra BS.

[SappySE107]

Those injectors can be tuned with your setup.

[3400-95-Modified]

I'm willing to bet your VE table is scaled too high which is resulting in the rich condition... You need to just do simple math to figure out what the ms number should be using the original injector flow rate and ms setting and your new flow rate, and then you adjust the VE to fix the richness... If you take the injector ms level and keep dropping it then your lying about what your injectors are doing and just adjusting for that lie in other areas.

The Injector flow rate should be a measured number for what your injectors can do at WOT, or what they've been tested at... its somewhat of a foundation for your tune.

[americasfuture2k]

I remeber him saying the ms was 8... Maybe .8? I don't remember. The joys of a head injury that results in a shitty memory.

[DefEddie]

8ms is too high.
IF you need some smaller injectors give me a PM,I've got a few sets laying around some FORD and some other's.
I'll be in OKC tuesday also so you can pick them up from me at the childrens hospital if you want or I can leave them with my uncle.(He lives over in Eagles Nest.)

[Superdave]

Those injectors can be tuned with your setup.

x2


If i can do it, a "pro" should be able to.

[3400-95-Modified]

8ms is too high.

I'm obviously not familiar with OBDI, but how is the IFR listed?

OBDII is ms/gram, for example mine was 459.15ms/gram with 16lb injectors, and it is now, 278.75ms/gram

Not to call anyone stupid, but to ward off confusion thats simply means how many milliseconds does it take for your injector to flow a gram of fuel... of course this is at a full pressure state... so when you have engine vac your IFR is in turn lower, which is why they incorporated that into later bin files by making the IFR table scaled by MAP readings, My bin has a table with 0-100map, so I can in turn scale down the lower half of my table if I desired to calculate the flow difference with my pressure drop.

What configuration is in a OBDI file? I was messing with one but that was so long ago I cant remember what that setting had for a scale.

[IsaacHayes]

Yup, make sure the BPC is calculated RIGHT for your size injectors AND displacement. (you are probably using A1, which is 3.1, and you have a 3.5)

If you don't set it to what it should be, all of the calculations the ECM uses to calculate what it needs to do get thrown off, and you end up having to fight things and adjust other things to compensate for it when you shouldn't have to...

Adjust the BPC right, then tune the VE. Done.

If he can't tune for 36lb/hr injectors, find a different guy to tune....



And 24 lb/hr will not support your motor. It's cammed with headers and a 3500... yup those will be maxed out....


EDIT: Jon, OBDI uses Base Pulse Constant instead of IFR. It's a calculation based on displacement and injector size. It's easiest to take a known BPC with known displacement, and injector size (say 3.1 and whatever their stock injectors are) then use math to come up with new values for your different displacement and injector size... And don't use liters for calculating, that's not accurate enough, use actual CC's of the motor (as we all know a 3400 is not really 3.4L, they rounded).


See my guide here, it has some info on figuring out BPC... (yes the guide is not done yet, but has good info still)

http://isaachayes.60degreev6.com/OBD1swap/94-95_LBody_Tuning_Guide_BETA_11-16-09.pdf

[3400-95-Modified]

EDIT: Jon, OBDI uses Base Pulse Constant instead of IFR. It's a calculation based on displacement and injector size. It's easiest to take a known BPC with known displacement, and injector size (say 3.1 and whatever their stock injectors are) then use math to come up with new values for your different displacement and injector size... And don't use liters for calculating, that's not accurate enough, use actual CC's of the motor (as we all know a 3400 is not really 3.4L, they rounded).


See my guide here, it has some info on figuring out BPC... (yes the guide is not done yet, but has good info still)
http://isaachayes.60degreev6.com/OBD...A_11-16-09.pdf

Ok, very similar to figuring out IFR though... Its hard to get a ms/gram value when starting with a lb/hr value Its much easier to take your two injector sizes, 16 and divide by 28 (in my case) get a result of .5714 and then multiply that by your current IFR, since my new value needs to be 57% of the old one, yadda yadda...

So yeah in the end I think we all agree... Time to boot the tuner and get a real "Pro" who knows what to do.

[robertisaar]

Tooner.

[Superdave]

what happened to the tune that i sent you a while back?

[americasfuture2k]

thats the one he was using. i believe hes using tunercat. said he cant go below 8ms bc going that low for a lean condition, it would be shutting banks off and it just wouldnt run right. maybe its tunercat. i dunno. ill get merlot to reply on here since he understood and remembers it better than i do. the joys of a brain injury

[robertisaar]

what???

can't go below 8ms????

[IsaacHayes]

With the latest definition from Robert tunerpro rt has TONS of items opened up.