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I'm liking this build, I have a sweat spot for GN's.
Whats the average stall speed of the 17-0's from PTC?
Merry Christmas
“Stall speed” is based on horsepower. I can tell you this, with a 15-0 on my sbe 5.3 with the limiter disabled and 30 psi on the dome, it made 20psi at 5k in at or under 2 seconds. I’ve got the log to prove it. The 9.5 PTCs loosen up the more power you make either on the brake or at shift recovery. The 15-0 was too tight for my 5.3 at my power level. The flash off the brake (leaving on 5–7 psi) was 4850-4900 as was the shift recovery. Didn’t matter if I shifted at 6500 or 7k, it’s not gonna change. The only way to bring up both the flags off the brake and the shift recovery is to throw a lot more power at it. So I loosened it to a 17-0 and it’s much happier. Flash and shift recovery both came up about 600-700 rpms, which is much better for my setup. So to answer your question, a 15-0 at my power level “flashed” at 4850-4900. The 17-0 at the same power level goes 5500-5600. Put either behind an engine making more or less power and those numbers will change again. BTW, the lockup on the 9.5 PTC converters on unreal. I’m not talking about the lockup converters, I’m talking about the lack of slip at the shift and down track. I won’t give any specifics, but I’ve got logs to prove that too. Believe me when I say they get tight!
Yes my real concern was it might bend rods easier with the sbe and a 6.0 with a 15-0 ptc . I’m not saying the car is slower with the tight converter as it might be faster with the load than blowing thru a looser setup but I don’t like the full lock up at 5200 rpm and 16 psi boost . I feel it is working the rods pretty hard .
Yes that is a big concern for me also, even budget builds are not considered budget up here so every penny counts.
Are both of you using the PTC "budget" version or their $1200 unit? Sorry if it feels like a hijack of the thread.
“Stall speed” is based on horsepower. I can tell you this, with a 15-0 on my sbe 5.3 with the limiter disabled and 30 psi on the dome, it made 20psi at 5k in at or under 2 seconds. I’ve got the log to prove it. The 9.5 PTCs loosen up the more power you make either on the brake or at shift recovery. The 15-0 was too tight for my 5.3 at my power level. The flash off the brake (leaving on 5–7 psi) was 4850-4900 as was the shift recovery. Didn’t matter if I shifted at 6500 or 7k, it’s not gonna change. The only way to bring up both the flags off the brake and the shift recovery is to throw a lot more power at it. So I loosened it to a 17-0 and it’s much happier. Flash and shift recovery both came up about 600-700 rpms, which is much better for my setup. So to answer your question, a 15-0 at my power level “flashed” at 4850-4900. The 17-0 at the same power level goes 5500-5600. Put either behind an engine making more or less power and those numbers will change again. BTW, the lockup on the 9.5 PTC converters on unreal. I’m not talking about the lockup converters, I’m talking about the lack of slip at the shift and down track. I won’t give any specifics, but I’ve got logs to prove that too. Believe me when I say they get tight!
I'm pretty happy with my 15-0 from PTC, minus it always falling back to 6200rpm on the shift. Doesn't matter if I shift at 8200 or 7500 its the same. Mine flashes to 6500rpm leaving on 12psi, here is a shot of a 1/8 mile log. 4300lbs and a built 5.3 with twin PTE 6870s at 38psi.
Yes that is a big concern for me also, even budget builds are not considered budget up here so every penny counts.
Are both of you using the PTC "budget" version or their $1200 unit? Sorry if it feels like a hijack of the thread.
I'm pretty happy with my 15-0 from PTC, minus it always falling back to 6200rpm on the shift. Doesn't matter if I shift at 8200 or 7500 its the same. Mine flashes to 6500rpm leaving on 12psi, here is a shot of a 1/8 mile log. 4300lbs and a built 5.3 with twin PTE 6870s at 38psi.
Exactly my point. The 15-0 at your power stalls at about 6300.
I'd go looser on the stall while its out and easily changeable personally. I ran a 14, 15, 15.5, 17... Over the years. Every time I went looser I picked up, better drop on shifts etc. Making 900-1000ish crank I'd guess. If you aren't shooting for the moon power wise, I'd think a 17-2 even an 18 would be a better match. My 17-0 drove great at 3000lbs with a 3.64 gear and 28" tire. Still dropped 1300ish rpm on the shift and didn't flash as high as I requested off the brake. I went with a 19-2 this time around. Was tired of the huge drop on the shift and stall never hitting where I asked it to.
Trying something different with my hotside. A little more equal length and a better flow of pipes to my t6 flange. Going to be tight to radiator but should fit. Eather way it is tight with keeping inner fenders.
Trying something different with my hotside. A little more equal length and a better flow of pipes to my t6 flange. Going to be tight to radiator but should fit. Eather way it is tight with keeping inner fenders.
Looks great. Was gonna do that with my Nova but it ain’t happenin. Turbo ended up in the “normal” spot.
Sorry for the thread hijack, and btw I love the GNs. Hard to find them anymore. Peak torque and hp are at 7500rpm in 1st gear due to the boost ramp. In high gear peak torque is about 6300rpm where boost isn't ramping up anymore and holding steady. The PTE 6870s are maxed out on my combo in 1st gear at 7500rpm and 35.5psi. I run a 30" tire and 3.42 gear with 1.80 glide. Works very well on the street.
Starting to get things buttoned up. Down pipe and driveshaft this week then a bunch of loose ends and start her up . Hope to have it running in a couple weeks. Also went to an ls2 intake for a better look .
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