Pull Truck Tuning

[Dom_c13b]

Was wondering if any of you guys would be willing to share what the max timing you've ever run is? Story is, I've been tuning a local 2.5 class pull truck. Setup is a Blacks 6.4, Turbo is a 96mm comp with a 2.5 insert, 103mm turbine, t6, 250% over injectors, twin cp3, one is a 12mm on one 10mm, 6.7 rail sensor. Anyhow I've been running it at 2250uS duration, 29k psi and 45* timing up top. It's made 820hp and 1280tq on a really stingy mustang dyno.
Looking at the logs it looks to me like it wants more timing, you can see the rpm rate of rise start to fall off with the timing curve, it follows it to the T. I've tuned a couple hundred trucks but not a lot like this and I'm a little nervous to give it anymore timing. I was hoping that one of you would be so kind as to give me a little insight. I appreciate the help.
Thanks,
Dominic

[2007 5.9]

How are you deciding your timing? Split or?

[Dom_c13b]

I started out going by split but am now way beyond what I was previously comfortable with. I'm also looking at total degree's of injection and trying not to go much past 60 total degrees of overall injection and trying not to surpase 20* ATDC.
Thanks for the help.

[2007 5.9]

I target 12-15*ATDC which will make you lower your pulse, thus needing more injector

[Dom_c13b]

I would like to try lowering the pulse while leaving the timing map as is. But that would put me into the 90%+ split range. As I mentioned before from looking at the logs it seems like it needs more timing, but less fuel with the same timing might help as well?
I'm starting to think that the 2.5 chargers just do not move enough air to make big power. It just seems strange that I can only get 820hp out of something with such a big turbo and fuel setup. I'm making the same power out of my truck with a 369sxe and injectors that are less than half the size. When I agree'd to tune this truck I thought it'd be an easy 1000hp, boy was I wrong.
The truck has gone through 3 tuners now if you include myself, the other two were big name guys (Miliken and Fuller) and the truck ran good but the power has always been in the same range. I was able to get a bit more out of it but I equate that to being local and being able to tune in person and see what the trucks doing. All of the other trucks I've tuned have been street or drag trucks with real turbo's on them. They've always done close to what I expect.

[RD TRCTR]

How are you deciding your timing? Split or?


I started out going by split but am now way beyond what I was previously comfortable with. I'm also looking at total degree's of injection and trying not to go much past 60 total degrees of overall injection and trying not to surpase 20* ATDC.
Thanks for the help.

Are either of you willing to elaborate on timing and split?

[Dom_c13b]

Split is the split of duration. So if you have 2000uS of duration and have a 50% split you're putting 1000uS of duration in before TDC and 1000uS of duration after TDC.

[kyle027]

Did you end up figuring anything out on the truck?

[Dom_c13b]

Went to 400% over injectors this year and a set of Manton Roller Rockers. Making the same power with 600uS less duration. Sitting at 1650uS duration now and maxing out around 36* timing instead of 2250uS and 45* that it was at last year. Still making the same power, just can't get anymore out of this charger.

[Orange Stroker]

Do the 400% have body mods?

Truck I tuned not long ago with dual stock pumps, s476sxe and 400% DDP Injectors with body mods
made 1070 at a 1000us file and 15.5* at 3900rpm which is where peak power was made which is 66% btdc
made 1075 at a 1200us file and 18.6* again at 3900rpm which is still 66 btdc.

I played around clear up to 85% btdc and it just kept loosing power above 68% btdc

That being said each truck is a little different and you will have to find the happy spot as each injector is different from how they atomize. I think if they atomize like shit then you will need to extend the timing out farther and farther to hit the sweet spot of when they atomize to make best power. So you might try pulling some timing and see if you gain some power back.

[Dom_c13b]

They are II 400's, I believe they have body mods but who knows. I've got a FI 488 ETR on the way for it, we'll see what it does with that.
I have played with timing on the dyno with this truck and where it's at now is where it wants to be. I tried pulling timing back and tried adding more and it lost either direction.

[Orange Stroker]

What about pulling PW back till it drops more then about 20hp? 1650us for 8-900hp on 400% seems like way too much fuel and you could even be drowning the cylinders where it is running too cool. Have you ran on the dyno lower then 1200us pw? You could probly lower cylinder pressure dramatically by pulling some fuel and timing and still make same power. Like the 400% i did made 750hp with 700us, 950hp with 900us, 1070 at 1000us and 1075 at 1200us. So I could see I clearly ran out of air so I don't feel that the extra fuel. I didn't try going past 1200 us as I felt power would just keep falling off from too much fuel as well as making it harder to pedal on the line to get charger lit.

[Dom_c13b]

What kind of Dyno are you using? This dyno is notoriously low. It's a big Mustang that always disappoints haha. Example, my personal truck in my sig, I put down 735, then the next weekend went down on the mobile dyno and put down 825, no changes made to the truck or tune. So please take the numbers with a grain of salt, to an extent anyhow.
This year with the 400 overs I started at 1200uS/18* timing and went up from there. The 1200uS tune I believe put down 680 if I recall correctly. I really think these s5xx turbos are the problem. My theory will be tested in a couple weeks when the 488 ETR shows up.
Doesn't run too hot, 1750-1800ish is the recall on the edge after a typical pull.
Last year with the 250% overs running 2200uS it ended up around the same HP, just couldn't get anymore out of it. All I know is if the new turbo doesn't make more power then I've got myself a 488 to put next to the 69 on my truck.. haha

[Orange Stroker]

What kind of Dyno are you using? This dyno is notoriously low. It's a big Mustang that always disappoints haha. Example, my personal truck in my sig, I put down 735, then the next weekend went down on the mobile dyno and put down 825, no changes made to the truck or tune. So please take the numbers with a grain of salt, to an extent anyhow.
This year with the 400 overs I started at 1200uS/18* timing and went up from there. The 1200uS tune I believe put down 680 if I recall correctly. I really think these s5xx turbos are the problem. My theory will be tested in a couple weeks when the 488 ETR shows up.
Doesn't run too hot, 1750-1800ish is the recall on the edge after a typical pull.
Last year with the 250% overs running 2200uS it ended up around the same HP, just couldn't get anymore out of it. All I know is if the new turbo doesn't make more power then I've got myself a 488 to put next to the 69 on my truck.. haha

Haha There you go. I gotcha maybe the injectors don't have as much for body mods. Not sure. My dyno is a DynoJet but it has always been 10-20hp lower then 4 mustang dynos around me.

The turbo will tell you alot for sure!!

[Orange Stroker]

What kind of Dyno are you using? This dyno is notoriously low. It's a big Mustang that always disappoints haha. Example, my personal truck in my sig, I put down 735, then the next weekend went down on the mobile dyno and put down 825, no changes made to the truck or tune. So please take the numbers with a grain of salt, to an extent anyhow.
This year with the 400 overs I started at 1200uS/18* timing and went up from there. The 1200uS tune I believe put down 680 if I recall correctly. I really think these s5xx turbos are the problem. My theory will be tested in a couple weeks when the 488 ETR shows up.
Doesn't run too hot, 1750-1800ish is the recall on the edge after a typical pull.
Last year with the 250% overs running 2200uS it ended up around the same HP, just couldn't get anymore out of it. All I know is if the new turbo doesn't make more power then I've got myself a 488 to put next to the 69 on my truck.. haha

Just out of curiosity are you running early or late pistons?

[Dom_c13b]

late pistons

[Apples24v]

Any updates? Did the 488 make a difference or do you have a set of compounds on your truck now lol

[Dom_c13b]

Got it on the dyno with the 488, and first pull the trans let go.. Just can't win with this one haha. They have a new trans for it now but the season is over so they are in no rush to get it back together and in the truck. I'll update when they do.

[Williamrush]

I am working on a similar project right now. It is going to be my first time tuning a pull truck. I really hope everything is going to be fine, as I really like this idea, however I have never had a similar experience before. Mine is also having a 103mm turbine, and I do not know what to do with it, should I replace it, or not. I have been using this truck back when I was working for a car shipping company. It was a great company actually, it was developing really fast due to the services of best trucking factoring companies (https://factorforyou.com/trucking-factoring-companies/) as they invested a lot of money into out accounts.