power past 4k

Now that is interesting, cutting rack travel produces peak power lower in the rpm band. I would have guessed that would only have changed the very top end. Good to know, thanks Will.

96 3500 5x018 7mm dvs 62fmw
 
Heading to the track tonight, just got two new tcms one with 2900 shift schedule and the other with 3600 just to compare some data. i understand my setup may not fuel or breath up above 3300, but shouldn't i be able to free rev the truck past 4120? fuel pressure was raised to 60lbs.. Thanks guys.. no smoke out the tailpipe after 3600... Any thoughts?
 
Big Blue24 said:
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.
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I'm jealous that you get to do this as a day job. :clap:
As always, thanks for sharing!!
 
Mic your current gsk stud protrusion, keeping everything in order, then swap some 5k gsk's in to try. What you find at the track will tell you if its worth the time.
 
T-MAN said:
Heading to the track tonight, just got two new tcms one with 2900 shift schedule and the other with 3600 just to compare some data. i understand my setup may not fuel or breath up above 3300, but shouldn't i be able to free rev the truck past 4120? fuel pressure was raised to 60lbs.. Thanks guys.. no smoke out the tailpipe after 3600... Any thoughts?
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When you say it wont free rev past 4120 does it just stop there or kinda pop.
 
Hello, got rained out tonight so no racing, there's a set of 5k spring for sale on here from cds ? are they any good... I dont have any 5ks to try . the truck will run up to 3900 then creep to 4120 no more and no popping it just lays down no load, same as it does under a load but that wont go past 3900 and it takes awhile to get there. i tried to get dyno time this week but no luck, next week. the reason i posted again was the 3600 tune wanted to shift @ 4k when i would get to 3900 i would lift and it pulled pretty hard in the next gear.... was just wishing for a couple more rpm. i dialed it back and its shifting at 3460 now and feels strong also but the rain set in.. is there anything else other then govenor spring that control free rev if you have fuel pressure, full throttle and the shut off lever all the way up ? it actually reved the same rpm @ 15* of timing that it does @25* but it revs faster now and i lost some boost... thanks in advance for any help..
 
Gov springs, I've been happy with the ones from Garmon diesel 5k's with the replacement seat. Haisley machine 5k's are a good choice also. What you decribe is your problem, delivery valves also make a big difference over 3k.
 
I use to run a 62/80 combo with a similar build to yours, and like most have said, your power-band peaks in the low 3000s. I got my best times with that build shifting 3300-3400.
 
Got to test new tcm this am, had it shifting @ 3k was in overdrive around 74mph pulling real good....68psi boost and 1400 max egts..then see attached pics.. any ideas other then heat...looks like it was torched but only the one valve....IMG_2718[1].jpg

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jlbayes said:
Valve not sealing.
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hello, nothing ls bent and the valve lash was still at .020 .... new springs as well and didnt miss. Whats the best wat to fix ? hardened seats with better valves ?
Does anybody on here have a good oringed head ready to bolt on they want to sell?
Or a vendor with one in stock set up with better valves and oringed?
If none of the above maybe some advice on who to get the parts from and a good machine shop near me in ny ... im at the ny,nj , pa tri state border.
Thanks for any help this sure did ruin the weekend.....
 
Yes the turbos are good, the valve actually looks like it was cut with a torch, nothing broken or chipped just melted...im sure this could have gotten worse pretty fast if i didnt let out of it, only reason i lifted is i was out of road...
 
The valve does not have to be bent to not seal. I'm thinking more along the lines of a small piece of debris was stuck to the seat or valve creating hot spot.
 
I'm in the same boat. Ferrell stg 3 with 5Ks, Stock cam and 62/475, runs out of air after about 3800 and just kinda falls on its face.


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