Dynamic EFI tuners in my area? Northern, CA Bay Area

[Schurkey]

How are the stock injectors rated? I'm thinking the plain ol' ordinary 5.7L TBI injectors are 55--60 Lbs/hr at...13 psi? There's some "Police" 9C1 injectors at ~62 or 63 lb/hr, but are they rated at 13 psi?

Injectors that pump 60 lbs/hr at 35 psi are going to be way too small, if the OEM injectors are rated for the same volume at the much-lower TBI operating pressure of ~13 psi.

But I'm not sure what pressure the TBI injectors are rated at.

 

[PlayingWithTBI]

I'm thinking the plain ol' ordinary 5.7L TBI injectors are 55--60 Lbs/hr at...13 psi? There's some "Police" 9C1 injectors at ~62 or 63 lb/hr, but are they rated at 13 psi?

Yes, most of them are rated at 13 PSI except the 94-95 7.4L ones. They're smaller and run at 26-32 PSI, 28 being the norm (as seen on the chart I posted)

I tried running my 5.7L with that 28 LB spring and the stock 61 LB/HR injectors but, as @tayto said, without a VRFPR I couldn't get it to idle well. with an 18LB spring my injectors were running 106% DC at 5400RPM and 90 MAP (on one of my logs). Now I am running them at 20 PSI (jacked up the 18LB spring) and my idle is acceptable. Although my VE tables are up over 90 at higher RPMvsMAP cells.

OP - try adjusting your BPC and see what happens. Then maybe take your VE tables and multiply by 1.3 or something like that until your highest cells are ~85-90. If it runs better, then you can do the "VE Learn" thing.

 

[arrg]

I'm using dual Siemens DEKA Shorty 60# hr injectors rated at 30-70 psi.

Do you have that Injector tuner thing from AFI that adapts newer high pressure style injectors to TBI?

 

[CHEVYS4ME]

That sounds like what I might need!

I'm trying some off the shelf 7.4l injectors now. I just installed them and an adjusting the bin.

I'm going to start at 18 psi using a vrfpr. Stock TBI timing tables should run decent enough to drive and do ve learn?

I also have a set of 80# hr Siemens DEKA Shorty injectors ordered. For emissions, those will be a lot better. They can flow really good patterns at lower psi and have been used on ulev vehicles. They operate efficiently from 30-70 psi. I'm sure they will work, I just need to get this thing on the road!

I'll post back in a bit how it runs with the standard motor 7.4l injectors, and bpc values from calculator

 

[CHEVYS4ME]

Do you have that Injector tuner thing from AFI that adapts newer high pressure style injectors to TBI?

Do you know where to find the higher psi injector scaler?

 

[PlayingWithTBI]

Stock TBI timing tables should run decent enough to drive and do ve learn?

With your fast burn style aluminum heads, you may want to get a little more aggressive. Here's a link where he discusses timing. At the bottom of post #3 he attached a spreadsheet so you can "play" with your timing too. The cells in it match the SA table in the EBL .bin, just copy and paste

www.thirdgen.org/forums/diy-prom/761049-spark-advance-table-example.html#post6301288

Of course you'll want to get your AFRs adjusted 1st.

 

[tayto]

How are the stock injectors rated? I'm thinking the plain ol' ordinary 5.7L TBI injectors are 55--60 Lbs/hr at...13 psi? There's some "Police" 9C1 injectors at ~62 or 63 lb/hr, but are they rated at 13 psi?

Injectors that pump 60 lbs/hr at 35 psi are going to be way too small, if the OEM injectors are rated for the same volume at the much-lower TBI operating pressure of ~13 psi.

But I'm not sure what pressure the TBI injectors are rated at.

I believe they are rated at 13 psi. regular 5.7L injectors are 61#. 9c1/police 65#, 5.0L 55#. Personally, I get every set of injectors cleaned and flow checked. Then you know exactly what you are working with. Have never messed with aftermarket injectors. Heard they are different than OEM, therefore the tune should really be updated for them. But of course there are no publish specs so you're on your own.

OP, i would find a place that sells refurbished injectors that come with a flow/test sheet but that's just my opinion.

 

[tayto]

Keep in mind, most of the vehicles I work on are problem units usually with a laundry list of problems. rebushing the throttle shaft and cleaning the throttle body along with getting injectors cleaned are part of my "recipe". this is done for reliability for the owner and so i don't have comebacks.

 

[arrg]

That sounds like what I might need!

I'm trying some off the shelf 7.4l injectors now. I just installed them and an adjusting the bin.

I'm going to start at 18 psi using a vrfpr. Stock TBI timing tables should run decent enough to drive and do ve learn?

I also have a set of 80# hr Siemens DEKA Shorty injectors ordered. For emissions, those will be a lot better. They can flow really good patterns at lower psi and have been used on ulev vehicles. They operate efficiently from 30-70 psi. I'm sure they will work, I just need to get this thing on the road!

I'll post back in a bit how it runs with the standard motor 7.4l injectors, and bpc values from calculator

You threw me with the talk about the Siemens injectors. You can't put those in a stock TBI unit.

 

[CHEVYS4ME]

You threw me with the talk about the Siemens injectors. You can't put those in a stock TBI unit.

With the optimum EFI pod you can...

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