Max rpm built 5.3?
Max rpm built 5.3? What kind of rpm would still be safe to turn? Aluminum block 5.3, arp main studs, summit h beam rods and forged pistons, stock crank. 222/233 cam. I’m shifting around 7000 currently but I think it’ll probably go at least 7500. I can dial in more boost up top to compensate for lack of camshaft. Why? I like rpm’s and the sound of it. Plus it may go faster. My trans might not like it tho.
well I tried to figure out what springs I have. Unfortunately Brian Tooleys website is a dumpster fire basket case when trying to find something so I had no luck there. I went grabbed the spring kit box to get the part number, well they use cheap *** tags on the box so the print has disappeared. The only thing I remember is they were for the bigger btr 228/232 cam I used to have in there. Double spring and titanium retainers, .650 lift iirc. So in essence, it’s probably a little over springed. The lifters are Johnson typify (I think). Been a while since I built the engine.
Joined: Apr 2006
Posts: 3,891
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From: Grand Rapids, Michigan
I don't know if it's over sprung for the RPM, especially considering that boost will actually drop your seat pressures by around a factor of 3 ( if you have a 2.00 valve, it's around 3 square inches of area, accounting for the stem ). If you run 15 PSI of boost, you're effectively dropping seat pressure by around 45 lbs. This can, at high RPM, cause valve bounce off the seat. This is why I went with BTR platinum springs with Ti retainers, and shimmed them to around 1.765" in order to compensate for the pressure loss under boost. You can also get into spring surge at times, so you may want to play around with shimming them to within .050-.060" of coil bind if you're really serious about frequent trips to 7500+.
I don't know if it's over sprung for the RPM, especially considering that boost will actually drop your seat pressures by around a factor of 3 ( if you have a 2.00 valve, it's around 3 square inches of area, accounting for the stem ). If you run 15 PSI of boost, you're effectively dropping seat pressure by around 45 lbs. This can, at high RPM, cause valve bounce off the seat. This is why I went with BTR platinum springs with Ti retainers, and shimmed them to around 1.765" in order to compensate for the pressure loss under boost. You can also get into spring surge at times, so you may want to play around with shimming them to within .050-.060" of coil bind if you're really serious about frequent trips to 7500+.
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7800 would be fine at this point with this motor. I’m currently doing some different fuel pumps in it but when it’s back running I’ll turn it up some more.
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Joined: Dec 2004
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From: Florida
ive got the elgin 1840 in mine and it clearly drops off at 6000 unfortuantely. i spun it up to like 72-73 on the dyno hoping for an excuse to always spin it up like that.
Spin it up son!
I shift my rod/piston LS1 at 7,000rpm so by the time everything takes place its around 7,500rpm.
BTR .660 drop in springs and Brute Speed FI cam which Bob says should make peak power at 6,800rpm.
I kinda disagree because my car feels good shifting all the way up to 7,500rpm.
If 8,000rpm shift points were my goal then I'd be copying @Pro Stock John combo with the Baker cam, lifters and springs because the cam will ultimately determine valvetrain performance and life span.
I shift my rod/piston LS1 at 7,000rpm so by the time everything takes place its around 7,500rpm.
BTR .660 drop in springs and Brute Speed FI cam which Bob says should make peak power at 6,800rpm.
I kinda disagree because my car feels good shifting all the way up to 7,500rpm.
If 8,000rpm shift points were my goal then I'd be copying @Pro Stock John combo with the Baker cam, lifters and springs because the cam will ultimately determine valvetrain performance and life span.
I don't know if it's over sprung for the RPM, especially considering that boost will actually drop your seat pressures by around a factor of 3 ( if you have a 2.00 valve, it's around 3 square inches of area, accounting for the stem ). If you run 15 PSI of boost, you're effectively dropping seat pressure by around 45 lbs. This can, at high RPM, cause valve bounce off the seat. This is why I went with BTR platinum springs with Ti retainers, and shimmed them to around 1.765" in order to compensate for the pressure loss under boost. You can also get into spring surge at times, so you may want to play around with shimming them to within .050-.060" of coil bind if you're really serious about frequent trips to 7500+.
The dynamics of the intake port are not static. You need to think in an actual operating condition. The other side of the valve also has a lot of "stuff" going on. In my experience, boost will have "minimal" effect on the spring pressure.
As an example I had a 1218 spring on my combo I was pushing pretty hard with a small wheel T4 in the early days. I saw 2.8:1 back pressure @ 26lbs. Thats 72.8 psi of back pressure... My combo pulled clean to 7k easily. Going by your math I'd be dropping 90ish psi off a spring that only has 130 psi seat pressure. I'd have all kinds of issues if what you say is true.
Not saying it doesn't have any effect... but its negligible in most cases.
Fwiw I've run the BTR platinum .660 dual spring kit to 7800ish with an untouched 5.3 valvetrain (aside from push rods and springs) That's original lifters/rockers with no trunnions etc. Also done the same with summits drop in lifter. Which I can only assume is offshore. the SBE record holder guys buzz to 8400 with that same spring kit at 40-45+lbs. Which again I'd think would be impossible if the above mentioned theory was correct.
I'll say longevity is likely greatly reduced... but so far so good.
My car goes no faster or quicker shifting at 7400 than it does shifting at 7000. My TH400 has no lag so it shifts when I move the lever.
I would think more cam with better springs etc would make a difference.
Ron
I would think more cam with better springs etc would make a difference.
Ron
Why mess with a solid combination for a few tenths and spoil it?
I had the exact opposite experience. Each time I went with a taller gear and revved the combo out more, I picked up more et/trap. Started out long ago in 2012 with a 212/212 @ 112 baby cam and 3.00 gears on a 30” tire revving it out to 6500ish. (my very first poorly setup combo I spec'd myself after racing low RPM turbo Buicks 
)
Many progressively higher RPM combos later… I ended up with a 226/230 @ 113+4, a 3.70 gear, and a 28” tire. Winding out and 7500 rpm. That cam wouldn’t pull beyond 7500. Later combos I target 7800ish with a larger cam. Was a glide though… felt like extending the shift point really helped with a 2 speed. I'd gained a solid 2+ mph in the 1/8th shifting at 7800 vs 7000 in my latest setup.
)Many progressively higher RPM combos later… I ended up with a 226/230 @ 113+4, a 3.70 gear, and a 28” tire. Winding out and 7500 rpm. That cam wouldn’t pull beyond 7500. Later combos I target 7800ish with a larger cam. Was a glide though… felt like extending the shift point really helped with a 2 speed. I'd gained a solid 2+ mph in the 1/8th shifting at 7800 vs 7000 in my latest setup.