Ok so I致e been messing with this tune trying to get my WOT in order. So I知 running a 355 with superram, AFR 180 heads, lingenfelter 211/219 cam, 1.6 rockers, headers. I知 running 24lb Bosch 3 injectors. I知 hitting 80% duty cycle by 4300 rpms. 85% by 4800 rpms,goes all the way up to 90 by 6000. Yeah I know 6000 rpms. I知 debating on just stepping up to 30 pounders I知 having trouble getting it dialed in past 5000. I知 guessing it痴 the duty cycle. Am I wrong wanting to go with larger injectors?

 

What does "trouble getting it dialed above 5000" mean exactly? What trouble are you having?

90% IDC really isn't a problem. ICD is only a problem if you reach a point where you aren't getting any additional enrichment for increased IDC.

IDC is open time during intake valve opening and can be well above 100%. It isn't unusual with bank fired injection to see enrichment continue to climb well above 120% IDC. It's certainly not ideal to have it above 100% but I've seen engines successfully tuned at 140% IDC. Obviously the customer was told they need more injector.

I have a similar build and am using 42lb injectors.

Whatever you buy - make sure it comes with offsets and flow data.

GD

 

Yeah when I bought these injectors it came with no info. I believe I found the info on these awhile back. But how accurate it is who knows. I知 thinking about 30 pounders from south bay. But again what if I eventually build a 383, should I go bigger more like 36 just so I知 not buying injectors again later. I thought about accels but I致e read bad things. I知 also running the EBL flash2.

 

Southbay are nice people and they really want to help but are not capable of actually testing for the data needed to do proper tuning. For EV1 injectors I went with Holley on the most recent engine I did for a customer - data was included. On my FIRST manifold daily driver I had the manifold machined for LS injectors and used 42lb Deatschwerks injectors which came with excellent data.

Again - Southbay are REALLY NICE people. But the only data they have is the same data you can search for online and we both know how accurate that is. I would buy from an injector supplier that can actually test for and provide the flow and offset data. Deatschwerks, Injector Dynamics, and Holley come to mind. There are probably more but that's who I have used and had no issues with any of them.

GD

 

Ok so would these work? They are not listed for for my car. Holley site only showing the accels with make and model. https://www.holley.com/products/fuel.../parts/522-308

 

Yep those will work just fine. I use the 36lb version in a recent build for a customer. Worked great.

GD

 

If you're going for 30lb, there are cheaper options... like the Ford M-9593-BB302

https://www.ebay.com/itm/8-Pcs-Set-3...0AAOSwNxte3wtM

These are the injectors I'm running and there's an actual datasheet for it (and I can vouch that these offset values work perfectly)...

https://performanceparts.ford.com/pa...9593-bb302.pdf

Looking at Holley's datasheet, you're going to be on the hook for tuning updates for these voltage offsets even if you go with their stuff. So, may as well go with the less expensive option.

 

thanks for the kind words GD ..question...ID and Deatschwerks sell 19lb-36lb injectors?? I was unaware of that.
I can tell you this...we do carry performance injectors from 550cc up to 2200cc and they all come with our own data. Sorry for any inconvenience

 

those offset are based on ford pressure, however there are multipliers for different pressures

 

Agreed. Though I think in most cases, if you are pretty close on the offset values, the average driver won't notice the difference. On my friend's car a while ago, we used my offsets on his Bosch-III's which were a different p/n and we couldn't find offsets specific to his injectors. It was a bone stock car in otherwise good operating condition that was hitting 150's on BLMs after the injector swap. After putting in my offsets, the BLM's came down to 120's to low 130's (which meant the fuel delivery was very close to factory spec) so we called it good since he said the car ran perfectly.

On my car, being heavily modified and me being far more picky, I put in the factory Ford offsets which got me very close. I then fine-tuned the various fuel tables since I had a WB O2 on the car. Probably could have adjusted the offsets too like you said, but I wanted the finer detail of tuning the VE, OL, AE, PE, etc individually...

So yeah, how far you go with the re-cal is likely a case-by-case basis.

 

Having incorrect offsets will result in unpredictable behavior as system voltage changes. Add or subtract accessories like radiator fans starting and stopping, and other system loads and you will alter the AFR of the engine due to incorrect voltage compensation.

Having the low pulse width data wrong will result in really skewed fuel table mapping values

Rules of tuning:

1. Give the engine what it wants.
2. Buy injectors with data.

There's plenty of injectors out there with excellent published/included data - the tuning community has driven the industry toward providing accurate data. It is VERY helpful and many tuners, myself included, will just refuse to tune the car at all without proper data. It's not worth the time to derive it. I have shown it can be done in other threads but trust me - no one is going to want to pay for that process - especially since injectors with data are cheaper than paying to have them characterized.

Again - there's JUST NO REASON to bother with injectors that have no data. PERIOD.

GD

 

No - they only supply larger injectors - which is fine for tuning. I'm running 42's on my 350 and they are still well above the low pulse width non-linear area at idle.

Holley does supply injectors right down to 19 though. With data:

https://www.holley.com/products/fuel.../parts/522-198

Of course they are not comparable in price to the reclaimed Bosch III's, but since Bosch won't let go of the data..... pretty much dead to me since I don't want to characterize them myself. Way more costly than the few hours that the difference in price would be worth converted to my hourly rate.

GD

 

I fought idle and low speed issues for years and tried three different sets of Bosch 3 injectors. I finally bought a set of 35# (18U-01-0035-8) Deatschwerks injectors and am very pleased.

 

I guess it depends. The datasheet I got for my injectors came off of Ford's website from their p/n (the p/n they assigned to Bosch's p/n). Whether or not they match Bosch's original factory data down to the last microsecond, I can't say. But I do know they work.

Agreed. I learned this hard way when I had originally bought some Bosch-III's second hand and didn't know anything about offsets. It was PAIN... IN....THE...A$$ to try get the card dialed in. After some research, I found out that it was the offsets and what offsets actually are and why they're there.

At that point, I went the opposite direction... looked for officially published datasheets on a 30 lb injector... Found these Fords with official Ford data, and then set out to find that exact part number (as opposed to buying injectors first and then looking for datasheets).

Literally as soon as I fired up the car I knew it was correct before even driving it... it was that spot-on.

 

All the big names for injectors have concluded that they NEED to include the correct, verified data IN THE BOX with their injectors. They have concluded this because of market pressure and competition in the industry. As a shop with a chassis dyno I am going to recommend the injector solution that provides the best results for the customer, and the path of least resistance for tuning. Which is a card in the box that tells me what values to input - preferably broken down by not only fuel pressure but also by the voltage break points used by each ECU - stock GM, stock Ford, AEM, Holley, LINK, etc. Injector Dynamics is a huge proponent of this approach and provides a TON of data on their injectors. They also have an iron clad minimum advertised pricing policy and their wholesale discounts to shops are better than 95% of the rest of the performance aftermarket.

GD

 

I agree that's clearly the most complete and comprehensive approach.