4.6 Stroker with Sprintex SC, Fuel Injector Size?

[FlyinRyan]

Auxilliary injector setups =

Not entirely true, daily driver with 5000 miles on system, 'flogged' on daily, running well and strong.

Sorry just my .02 , I've seen enough piggybacked setups with garbage drivability and lack of finesse when dealing with part throttle boost. I'll be tuning a 4.0 with a Sprintex this week.

If you are local, I invite you for a ride. It might just open your eyes and change your mind. Might be true with other, not me.[/quote]

I'm glad it is working well for you- and please don't take offense from my comments as they aren't meant to be inflammatory- but you cannot convince me that this sort of setup is not leaving any power, drivability, or mileage on the table. Not that I don't think it works- I'm sure at WOT or heavy load it is fine, but like any piggyback or device with a limited amount of control over PCM logic, it has limitations. I'm very passionate about tuning these vehicles, and I don't like ANY compromise on either control, or refinement. So, you'll have to forgive me if I am coming off sounding like a jerk- I just am borderline fanatical about getting these vehicles to put down the power they should be.

Pardon my lack of familiarity with this particular kit- where is the aux injector spraying? When is it triggered? How is it controlled?
How are you controlling timing? A retard box? Are you pulling a global amount of timing/lb for all boost pressure?

I'm in South Florida. I'd love to go for a ride, but it'd be more for the scenery than anything else. I counter your offer with an offer to ride in the M112'd Ram I mentioned above. Or the 10 Sec 1/4 mile Dakota RT I'm working on locally. Or any of the other trucks I tune...

[CobraMarty]

Shared passions.

"Pardon my lack of familiarity with this particular kit- where is the aux injector spraying? When is it triggered? How is it controlled?
How are you controlling timing? A retard box? Are you pulling a global amount of timing/lb for all boost pressure?"

- Under N/A conditions, the jeep runs just as normal, as programmed by Jeep with the stock injectors. The 7th inj and SS box are just sitting there, waiting for boost.
- the 7th inj is spraying into the SC. It is located below the TB, in the housing bolted to the inlet side of the SC and points directly into the SC.
- It is controlled with a split second control box, this box has an AIC-additional injector controller, MAP clamp, True tach signal, timing retard, and 2 bar map sensor. the AIC pulses the injector with each firing of stock injectors, that is, it fires 3 times each crank revolution, it is programmed in a table of boost pressure vs.rpm and pulse width desired(0.0-10.0ms). The timing is retarded also programable table boost vs rpm and degrees of timing retard desired(0.0-20.0degrees). The MAP clamp is used to clamp the stock MAP sensor at 4.8v as it is plumbed directly to the charge intake manifold and it sees boost. Not clamping the stock MAP in this location will cause a CEL. But also seeing under about 2 inches of vacuum or boost, and outputs over about 4.6v, it immediately puts the ecu in 'open loop'. This open loop control seems to have ultimate priority over all and any other parameters like rpm,speed,temp,etc. With the stock MAP sensor under the TB it will usually never see under about 2-3 inches of vacuum and won't go into open loop, unless over ?3500rpm. This is where there are part throttle/low boost problems/issues, if it is not done this way. There has to be control over going into open loop with boost.

What you do with the ECU for these stroker guys with larger injectors is wonderful. I have refered many to you.

[CobraMarty]

The sprintex produced a 41% increase in HP on a 2005 TJ with an inline 6.

Do you have more details on this TJ? starting hp, boost, s/c'ed hp? What did he use for fueling and timing?

[Coffee Commando]

Shared passions.

"Pardon my lack of familiarity with this particular kit- where is the aux injector spraying? When is it triggered? How is it controlled?
How are you controlling timing? A retard box? Are you pulling a global amount of timing/lb for all boost pressure?"

- Under N/A conditions, the jeep runs just as normal, as programmed by Jeep with the stock injectors. The 7th inj and SS box are just sitting there, waiting for boost.
- the 7th inj is spraying into the SC. It is located below the TB, in the housing bolted to the inlet side of the SC and points directly into the SC.
- It is controlled with a split second control box, this box has an AIC-additional injector controller, MAP clamp, True tach signal, timing retard, and 2 bar map sensor. the AIC pulses the injector with each firing of stock injectors, that is, it fires 3 times each crank revolution, it is programmed in a table of boost pressure vs.rpm and pulse width desired(0.0-10.0ms). The timing is retarded also programable table boost vs rpm and degrees of timing retard desired(0.0-20.0degrees). The MAP clamp is used to clamp the stock MAP sensor at 4.8v as it is plumbed directly to the charge intake manifold and it sees boost. Not clamping the stock MAP in this location will cause a CEL. But also seeing under about 2 inches of vacuum or boost, and outputs over about 4.6v, it immediately puts the ecu in 'open loop'. This open loop control seems to have ultimate priority over all and any other parameters like rpm,speed,temp,etc. With the stock MAP sensor under the TB it will usually never see under about 2-3 inches of vacuum and won't go into open loop, unless over ?3500rpm. This is where there are part throttle/low boost problems/issues, if it is not done this way. There has to be control over going into open loop with boost.

What you do with the ECU for these stroker guys with larger injectors is wonderful. I have refered many to you.

Oklahoma Superchargers told me it only fires when the first injector fires.. you said yours fires 3 times? That seems more logical. When they told me it only fires on the first injector that didn't seem right, it seemed like it would leave lean spots in certain cylinders.

I assume you have injectors 1,3 and 2 wired into your AEM unit Marty?

How do I get past the part throttle/vacuum issues faced when going into open-loop? I'm totally new to supercharging but I've got 5 months at my disposal before I install it.

Also, do you have a write up on how you did your windshield-wiper-injection setup? I read about diesels using water injection and became interested in windshield-fluid injection after much googling around about 5 months ago but somehow got sidetracked from it. The internet is one hell of a rabbit hole.

The sprintex produced a 41% increase in HP on a 2005 TJ with an inline 6.

Do you have more details on this TJ? starting hp, boost, s/c'ed hp? What did he use for fueling and timing?

I have it in a PDF file. If you give me your email I can email it, although it doesn't list what is controlling the 7th Injector.

Superchargers of Oklohoma uses an AEM-FIC unit to control the 7th Injector. I just assumed that that was how it was designed to be used, but now that I think about it for a kit like that it should come with a preset tune for control. Maybe it did, but I told Oklahoma that I was attaching it to a stroker so they used a previous 4.0 tune they had and enriched it. I'll have to lean it out to get it right.

[CobraMarty]

Firing with only the #1 injector is why I didn't use the AEM to control the 7th injector. Those who do are the same guys Ryan was talking about with 'kaboom'. Triggering that way will give just the 1 bolus of fuel at that time and then wait for the next #1 injector signal, 1 2/3 turn of the crank. Fuel bolus--wait--wait--wait--wait--wait--fuel bolus. That can give a lean spot between pulses and mal distribution of fuel to each cylinder.

It only goes into open loop when it sees about near zero vacuum or the first bit of boost. No issues. Smooth transition.

Turbo/superchargers have used water injection for years to cool down the charge air temp coming out of the turbo-s/c. Washer fluid just so it won't freeze here in PA. No need for 'meth' mixtures like from Snow. I use a kit by CoolingMist and use their boost triggered/progressive controller. The storage reservoir is from an early XJ and mounts like factory. Pictures are here http://www.cherokeeforum.com/f46/projec ... an-127621/ I plumbed the nozzle into the housing right next to the7th injector and both water and fuel go thru the s/c. That is my 'liquid/chemical' intercooler and why my charged IAT's are so low.

[Coffee Commando]

Wait, so can the AEM only fire based off of one injector reading?

What do you use for your Sprintex? I don't want no kaboom in my new stroker from Golen.

[CobraMarty]

Wait, so can the AEM only fire based off of one injector reading?

What do you use for your Sprintex? I don't want no kaboom in my new stroker from Golen.

Nice choice with the Golen. Will you get the 'boosted' version? I am curious how they work out. I would consider them for a longblock.

Yep, the AEM only triggers off one injector when using it to control a 7th injector. And at that you don't put in a pulse width value, it takes the single on-off signal (what ever that is) and then modifies it shorter or longer. It uses what ever the signal is as sent by the ecu. You don't know what that signal is. You have to just put in a 'modifying' value and then check the AFR to see what that value did. Not intuitive at all. You have no control over what the ecu sends it.
I used a Split Second box that I had built by them to my specs. There you can control exactly how many ms you want the injector to fire based on rpm and boost values. Also it fires 6 times per 2 engine revolutions so the fuel fuel is evenly spread over the crank rotation/engine cycle.

I hope this helps.

[Coffee Commando]

I just finished talking to Chad at Golen on the phone an hour ago. I put $2500 up front for the boosted long block with 30lb injectors. According to him they make about a hundred 4.6's a year and that he averages about 2, sometimes 3, a week.

He's custom building the engine with the stock camshaft and valvetrain on their aftermarket cylinder heads that fix the factor defect for the 00+ factory head. Diamond Forged Pistons with 30CC dish, 0.00 Deck with the mopar .043" headgasket, and the 5.875" Steel I rods.

DCR, according to the calculator, is 7.6 (SCR of 8.7). That should be safe for 6PSI.

The boosted longblocks make between 350-400 HP varying with 6-8 PSI according to Chad. Of course that will depend on other factors as well such as the camshaft, the intake and the exhaust. I'm only going to run a 62MM TB with simple 2.5" exhaust by magnaflow. I would prefer to run sub 350HP. I don't want to test the upper limits of my axles and want a good power/fuel efficiency balance. We'll see what I come out with.

[CobraMarty]

The 30 lb injectors sound a little too large for you. Maybe he was thinking that is what you will need to feed it with a supercharger with no 7th injector. For you, 30x6 + 50lb = 230 lb of fuel. That is a lot of fuel for your HP goal.

I thought most strokers liked 24lb injectors and then have Ryan tune it.
24x6 + 50lb = 194 lb of fuel.

[Coffee Commando]

194 can't be too much. When I opened up a thread about using the Avenger with a stroker everyone was telling me to use 42lb injectors, and that's 252lbs of fuel for 6 injectors. The whole reason I wanted to use a sprintext instead was to use smaller injectors.

Also, don't the fuel injectors have to be larger to compensate for spring into boost (vs. vacuum). ?