High boost 5.3 Headed to the Dyno, What Will it Make?
Thread Starter
Teching In
Joined: May 2019
Posts: 34
Likes: 5
High boost 5.3 Headed to the Dyno, What Will it Make? I'm headed to the Dyno on Thursday and I will post the results. But first, let's see who can guess closest.
The Setup:
Holley Terminator
5.3 liter 9.4:1 static compression
Summit Stage 2 Turbo Cam
Truck intake and TB
Decked 317 heads
Vs Racing 85mm T6 1.32 ar turbo
Huge 6 inch thick intercooler
Th400
8.8 rear end with 3.55 gear
FTI converter (I don't know the stall but it's pretty tight, shows 6% slip at the 1/4 mile)
28x10.5 Hoosiers
Ignite Red 114 Fuel (e90)
I plan on running 30 pounds (or more) of boost. I run 28 pounds regularly at the track with some room left in the boost controller.
I'm going to work up the timing. With the lower (ish) compression, everytime I've given it timing, its picked up at the track, but now I'm at the point I want to dial it in on the dyno.
This will be on a Dynojet dyno. I believe this is the big roller dynojet, the roller looked like it was 4 feet in diameter when I saw it, so hopefully it will load the car pretty good.
Supporting mods and other info:
Forged rods and piston, stock crank, aluminum block .020" over, Bosch 210 injectors, 2 DeatschWerks 350 lph pumps, ARP head studs, LS9 gaskets, 3" charge pipes, homemade truck manifold hotside, trunion upgrade rockers, BTR dual valve springs. Truck accessories, no power steering or AC
Post up some guesses! I know what I think it'll make!
The Setup:
Holley Terminator
5.3 liter 9.4:1 static compression
Summit Stage 2 Turbo Cam
Truck intake and TB
Decked 317 heads
Vs Racing 85mm T6 1.32 ar turbo
Huge 6 inch thick intercooler
Th400
8.8 rear end with 3.55 gear
FTI converter (I don't know the stall but it's pretty tight, shows 6% slip at the 1/4 mile)
28x10.5 Hoosiers
Ignite Red 114 Fuel (e90)
I plan on running 30 pounds (or more) of boost. I run 28 pounds regularly at the track with some room left in the boost controller.
I'm going to work up the timing. With the lower (ish) compression, everytime I've given it timing, its picked up at the track, but now I'm at the point I want to dial it in on the dyno.
This will be on a Dynojet dyno. I believe this is the big roller dynojet, the roller looked like it was 4 feet in diameter when I saw it, so hopefully it will load the car pretty good.
Supporting mods and other info:
Forged rods and piston, stock crank, aluminum block .020" over, Bosch 210 injectors, 2 DeatschWerks 350 lph pumps, ARP head studs, LS9 gaskets, 3" charge pipes, homemade truck manifold hotside, trunion upgrade rockers, BTR dual valve springs. Truck accessories, no power steering or AC
Post up some guesses! I know what I think it'll make!
Hoosiers will kill the numbers along with the auto too, but ya anywhere from 950-1000 should be expected. 84mm has done 1100 with a manual 5.3L, so factor in the additional losses and your right in that range.
If anything the fuel pumps may be a little close to maxed out at higher boost, the pumps drop down to 300lph at 70PSI assuming a 43 base.
If anything the fuel pumps may be a little close to maxed out at higher boost, the pumps drop down to 300lph at 70PSI assuming a 43 base.
Thread Starter
Teching In
Joined: May 2019
Posts: 34
Likes: 5
Well here it is! Interesting results.
I talked to the shop and they said their dyno disappoints a lot of people so it makes me think these numbers are pretty accurate. On the last two pulls they said it was spinning the tires some. I revved it up to a little over 7k rpm each pull.
Made 413 whp at 6000ish on 7lbs and 22 degrees (just making sure everything was straight and ready on the dyno)
Made 688 whp at 6100 on 22lbs and 16 degrees
Made 714 whp at 6200 on 22lbs and 18 degrees
Made 730 whp at 6300 on 22lbs and 20 degrees
Made 770 whp at 6300 on 26lbs and 17.5 degrees
Made 780 whp at 6400 on 28lbs and 17.5 degrees
Peak torque was 600-640 ft/lbs for all the pulls around 6000-6300.
AFR was at 11.3 ish. Fuel consumption peaked out right at 1000lb/hr on the last pull.
Since it stopped making power with boost we decided to stop there. It made 28lbs of boost with 34lbs of dome pressure (6 lb base spring with 3 port boost controller at 100%).
I wonder if a different intake would help the power. To me, I expected to see peak power around 6900 or so, not low 6000's. I also wonder if my flexpipes in the exhaust have blown out on the inside causing a restriction, making it not pickup power with the extra boost. Or maybe the cam isn't right for this combo. I feel like its odd it made peak torque so high and peak hp so low. What do you guys think?
I talked to the shop and they said their dyno disappoints a lot of people so it makes me think these numbers are pretty accurate. On the last two pulls they said it was spinning the tires some. I revved it up to a little over 7k rpm each pull.
Made 413 whp at 6000ish on 7lbs and 22 degrees (just making sure everything was straight and ready on the dyno)
Made 688 whp at 6100 on 22lbs and 16 degrees
Made 714 whp at 6200 on 22lbs and 18 degrees
Made 730 whp at 6300 on 22lbs and 20 degrees
Made 770 whp at 6300 on 26lbs and 17.5 degrees
Made 780 whp at 6400 on 28lbs and 17.5 degrees
Peak torque was 600-640 ft/lbs for all the pulls around 6000-6300.
AFR was at 11.3 ish. Fuel consumption peaked out right at 1000lb/hr on the last pull.
Since it stopped making power with boost we decided to stop there. It made 28lbs of boost with 34lbs of dome pressure (6 lb base spring with 3 port boost controller at 100%).
I wonder if a different intake would help the power. To me, I expected to see peak power around 6900 or so, not low 6000's. I also wonder if my flexpipes in the exhaust have blown out on the inside causing a restriction, making it not pickup power with the extra boost. Or maybe the cam isn't right for this combo. I feel like its odd it made peak torque so high and peak hp so low. What do you guys think?
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Is a boost curve normally stair-stepped past peak like that? Almost looks like it might be fighting something.
If you already answered this, my apologies- describe yourself valve train
If you already answered this, my apologies- describe yourself valve train
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Verdad Gallardo Nope that doesn't look right at all. Peak boost almost always peak torque.....I don't even understand how peak torque and peak power can be at the same rpm.
Thread Starter
Teching In
Joined: May 2019
Posts: 34
Likes: 5
The boost is constant across the rpm range for whatever I am asking for. Turbo lights around 4000rpm, it might be a few pounds shy at 5000 rpm, but by 5500 it is on target and will carry it out to redline. The valve train is BTR .660 dual springs, chromoly pushrods, stock valves, ls6 lifters, ls2 trays.
Dumb question as I have no boost experience- do you need bigger diameter pushrods running that kind of boost pressure? Wondering if that kind of pressure plus combustion pressure works out to just a really high ex valve weight?
Understood. I didn't know, which is why I asked. I guess to say it from a broader perspective I was wondering if it is valve float because of that stair-stepped look.
I agree, it does seem valvetrain related or maybe even back pressure related. Something is holding it back. I'm still confused on why the HP and torque peak at the same RPM per that PDF. You ever seen that?
Originally Posted by ddnspider
I agree, it does seem valvetrain related or maybe even back pressure related. Something is holding it back. I'm still confused on why the HP and torque peak at the same RPM per that PDF. You ever seen that?
That is some pretty underwhelming numbers. I agree, something seems quite off. You probably have a better combo than me, but I was hoping mine would make those kind of numbers or maybe better.
TECH Fanatic
Joined: Feb 2015
Posts: 1,080
Likes: 178
Somethings not right with the graphs. tq/hp crossover should occur at 5250rpm. Doesn't happen on that graph. Can the dyno operator email you tq/hp graphs overlayed? 1000lb.hr fuel translates to more than 780whp. Track results (mph) will tell the real story (better # than dyno). I'd expect a little more than 1000whp if fuel usage is correct.
Thread Starter
Teching In
Joined: May 2019
Posts: 34
Likes: 5
Somethings not right with the graphs. tq/hp crossover should occur at 5250rpm. Doesn't happen on that graph. Can the dyno operator email you tq/hp graphs overlayed? 1000lb.hr fuel translates to more than 780whp. Track results (mph) will tell the real story (better # than dyno). I'd expect a little more than 1000whp if fuel usage is correct.
I’m going to check to see if my flex pipes are collapsed first. One of the guys in the shop said the flex pipe was getting red hot on the pulls. I didn’t see it so I don’t know if that’s true or not, but it makes me think maybe that’s adding to the issue. It really should not have effected the 7lb wastegate pull though. I’d think the engine could push power through a restricted exhaust on 7lbs if it made 780whp a few pulls later.
I’ll post my data log and the new dyno graphs as soon as I get them. I’m out of state until Monday and I left my tuning computer at home.
I greatly appreciate the input.
