power past 4k

Hello, Im in need of some help with my 24valve that i have ppumped. Im having no luck getting it to pull past 3600-3700 rpm under a load. it will free rev to 4k without a problem.
motor is a 2001 24valve, hamilton 188/220 cam, 103# springs, ported head, 7x12 injectors flowed @3800 mililiters per minute and popped @ 260 bar, benched pump 550cc 035 delivery valves and 4k springs (should have full fuel to 4500), .093 lines and cross tubes, .020 marine head gasket , stock so pistons, 62 over a 478 twins and a adjustable pump gear.
I have checked all the basic things, full throttle, fuel shutoff ( i unhooked and zip tied full up) , fuel pressure is at 50 and timing.
Originally on the timing i set it to 21* and it missed real bad at 2100-2300 rpm so i advanced to 27* and that all went away.
I took it to the track and my best time is 12.17 @ 111 and no matter what i try it falls off around 3500-3600 rpm *72 lbs of boost
After speaking with the pump builder i found out the plunger lift chart is useless with a modified pump, so i bought a timing light adapter and i was only at 15* so i advanced to 25* at the injector and 31.5 at the pump it was 6.5* different. so now i thought i was good to go, truck feels snappier and sound different but still lays down around 3600.
Im not sure what other info may be needed to help me out but just ask.
sorry for the long post, just wanted to try to cover everything. Thanks in advance for any help.. and happy 4th of july..

What pump is on the truck? A 160hp pump without the upgraded pump cam doesn't like to rev. What are the turbine wheels and housing on both chargers?

Why are you trying to make power at 4k? With our ppumped 24v 27 degrees of timing and a 63 over s480 it made peak power at 3300 so thats where we shift.

It is nice to eliminate some drivetrain killing torque.

Thank you for the replies..

The pump is a benched 215 pump , i would have to look for the turbo specs.

not necessarily trying to make power up there just wondering why its not getting there, i want to get it on the dyno to see where my power curve is and didnt want to waste the money if i was missing something that was causing it not to rev..

on the turbo side i want to say 88 with a 110 housing and the htt 13 stainless with a 58 wheel , gated housing.
all in all the truck runs good, im just trying to get in the 11s in the quarter, im right there but cant seem to get it.

40ray, do you have a dyno graph you can post so i can see how fast the power falls off after 3300?
Thanks again for the replies im going to see if i can get on a dyno this week, if anybody has any other tips before i go let me know... any guesses on the horsepower?

Had same problem with s300 over s480 .. Found that s300 exhaust was to restrictive ,I switched to larger small turbo (exhaust wheel ) helped .. Went to a single s475 87mm exhaust wheel 42-4400 easy ...I used s464 87 .90 over a s480 1.32 great top end

Rich dzl said:

Had same problem with s300 over s480 .. Found that s300 exhaust was to restrictive ,I switched to larger small turbo (exhaust wheel ) helped .. Went to a single s475 87mm exhaust wheel 42-4400 easy ...I used s464 87 .90 over a s480 1.32 great top end

Click to expand...

Rich diesel , are you running this setup on a ppumped 24v? i was wondering with the turbos available today if i should have went with a single... the turbos i used i had for a common rail build that never happened back in 2012. how was the spool up with the single?

What's the truck weigh? What gears and what size tire?

Your setup is down on power for sure. I have a very similar setup and ran a 11.09 @122 at 6250 lbs(gutted). But my pump did about 500cc with full cuts and I'm only running a 6x13 injector.

Why 4 k springs in the pump and not 5ks? It will typically fuel harder all throughout the rpm range with the 5ks.


Sent from my iPhone using Tapatalk

mathews8pt said:

What's the truck weigh? What gears and what size tire?

Your setup is down on power for sure. I have a very similar setup and ran a 11.09 @122 at 6250 lbs(gutted). But my pump did about 500cc with full cuts and I'm only running a 6x13 injector.

Why 4 k springs in the pump and not 5ks? It will typically fuel harder all throughout the rpm range with the 5ks.


Sent from my iPhone using Tapatalk

Click to expand...

truck weighs 6880 with me in it, 3.55 gears and 285/75/16 tires. i went with the 4k springs because was worried about the idle problems and touchy throttle. i never wanted to run 5k but thought a solid 4k would do the job... was told full fuel to 4500. but cant get a solid 4k out of it. im sure its something with my setup. my old combination with the redline would fuel to 4k but would fall on its face after 3400 also. i have the same head with bigger injectors and slightly bigger turbos. i need to check the drive pressure. i have a video of the run but have to figure out how to post it, its from a verizon phone... i want that 11.09 lol

Honestly I wouldn't worry about making power past 3500 right now. You should have plenty of rpm for a lot faster mph before it hurts you.

The HP calculator shows 640 hp to the wheels at 6900lbs and 111mph. Your a good 100hp low in my opinion. How much boost is the primary making? No boost leaks? Trans is solid?

I'm hoping my injector swap this week nets a 10 sec pass... Lol. Been my goal for a while

Sent from my iPhone using Tapatalk

https://www.youtube.com/watch?v=sEUj5uUREb0
https://www.youtube.com/watch?v=JUXi1YNaZp8

hope these work, you can see the smoke die off at 3600, then shift at 3800 and the smoke is back...

I dont have a recall on primary but looks around 40-45 total boost was 72psi, after i bumped the timing im around 62...there was no leaks at the track 2 weeks ago, but i have blown 2 boots off the cooler on the hot side....Trans is an allison and is solid.......these runs were at 15* timing, i havent made it back to the track yet..the first video will be better served after a few beers.... lol

Can you make it shift around 3200-3400? Locking the TC in second? Really no reason to shift at 3800 with that setup IMO


Sent from my iPhone using Tapatalk

mathews8pt said:

Can you make it shift around 3200-3400? Locking the TC in second? Really no reason to shift at 3800 with that setup IMO


Sent from my iPhone using Tapatalk

Click to expand...

im working on that, thought it would be easy with a laptop hooked to it....lol trying a different program for this weekend. i can command the shift at 3200 but until the trans sees some kind of rpm drop it doesnt want to shift. just one of the few bugs to overcome with the standalone allison ( no torque reduction) converter locked at bottom of second gear. 1.76 60'. my old setup best 60' was 1.62.... and i think i agree on the 3800 now, if there's no power there i shouldnt be there...

You've got an Allison behind a p-pumped 24valve? That's a unique setup. Have you got a build thread? Why did you go with an Allison versus a 47/48re? Just curious how the Allison is working for you. Sorry to derail your thread. Thanks for any info.

I don't think you have a large enough air and fueling setup to make peak power at 3800 RPM, from the numerous trucks we've ran on the dyno, less than 5% make peak power at or above 3800 RPM.

Here's a dyno run of a 6.7 Common Rail with a large compound turbo setup, it appears to be fuel-limited because it hits peak power then slowly falls with RPM. Air limited trucks seem to fall off quicker in the upper RPM range.



Here's a graph from a big triple turbo 12 valve, notice how the torque graphs peaks late like the HP and therefore it makes peak power WAY up in the RPM range:


Here's the Junker:

T-MAN said:

Thank you for the replies..

The pump is a benched 215 pump , i would have to look for the turbo specs.

not necessarily trying to make power up there just wondering why its not getting there, i want to get it on the dyno to see where my power curve is and didnt want to waste the money if i was missing something that was causing it not to rev..

on the turbo side i want to say 88 with a 110 housing and the htt 13 stainless with a 58 wheel , gated housing.
all in all the truck runs good, im just trying to get in the 11s in the quarter, im right there but cant seem to get it.

40ray, do you have a dyno graph you can post so i can see how fast the power falls off after 3300?
Thanks again for the replies im going to see if i can get on a dyno this week, if anybody has any other tips before i go let me know... any guesses on the horsepower?

Click to expand...

Ill see if i can post it up. Ill tell you this the truck dropped 6 tenths off in the 1/4 by shifting at 3300 instead of 4k.

40ray said:

Ill see if i can post it up. Ill tell you this the truck dropped 6 tenths off in the 1/4 by shifting at 3300 instead of 4k.

Click to expand...

I saw similar results pulling, get it into high gear as soon as possible, let the turbo and torque do the work!

cottondoc,sorry no build thread, but if you have any questions i would be more then happy to answer them. i picked the allison because i wanted to be able to sled pull daily drive and drag race, i know this can be done with a built 47 but i like the idea of electronic tuning.. but it is testing me right now.

big blue, thank you for the graphs.. the junker puts things in perspective 3k and a rocket with over 900hp, nice...

40ray, those 6ths would be all i need to keep me just above the 11.50 mark, the earliest best shift at the track so far has been 3600. i ran a 12.25 at 111.xx and have been chasing my tail ever since. hopefully this friday i can get it to shift earlier....

zstroken, this will be the goal for friday....

thanks for all the replies

Big Blue24 said:

Here's the Junker:

Click to expand...

Will,
Where did you find works best for shift points? 2900rpm? Just curious. The junker makes power a lot lower than I was expecting!

CorneliusRox said:

Will,
Where did you find works best for shift points? 2900rpm? Just curious. The junker makes power a lot lower than I was expecting!

Click to expand...

When it was setup as an automatic VB, it would shift around 3000 rpm 1-2, 3200 rpm 2-3, and probably 2900 rpm 3-4 (that one I controlled with a switch and the earlier I shifted into OD/4th, the quicker it would go!)

Now with the full manual VB, it shifts when I command it. Those 10.90 passes a few years back were with the old 160 pump that fell off much sharper in the 3000+ rpm range and made somewhere around 725 peak HP. This new Farrell 215 pump fuels hard well beyond the RPM limits of the turbo setup and if I can get the head to stay glued down, it should run mid 10's and 130+ MPH....

The dyno is an interesting thing, if I turn the load way down or even off and only run it in inertia-only mode (approx 3000 lb drum weight) it will make roughly the same peak HP but it will happen at 3200 to 3300 rpm. So what we've seen on the dyno, is peak power rpm range is somewhat dependent on the load with higher load producing earlier peak power numbers.

It's also interesting to note that the as we cut back fueling duration or rack travel at the pump, the peak power RPM range falls as well. For example, if we had a truck that made peak power at 3500 rpm, and we cut back the fueling to where it makes 20% less power, the peak power might happen way lower like 2900 or 3000 rpm.