79 RX7 LS 5.3 Turbo. (8.93 @ 153mph)
07-12-2014, 12:20 AM
#202
New turbo makes a bit more power. Harder to get it to light off though. At 24lbs I managed an 8.94@157.6 with a crappo 1.47 60'. Also trapped 159 @ 25lbs creeping to 26 the last 100rpm or so. Thats shifting at 6k and 6200 through the traps.
Need this sucker to 60' and I could be mid 8's!
Still on the cheap china 32x12x3 IC as well. A treadstone IC is on the way. We'll see how much power that thing is eating up.
Need this sucker to 60' and I could be mid 8's!
Still on the cheap china 32x12x3 IC as well. A treadstone IC is on the way. We'll see how much power that thing is eating up.
Last edited by Forcefed86; 07-12-2014 at 01:18 AM.
07-12-2014, 01:42 PM
#204
The pressure drop across the cores is what seems to be the big factor. Ive heard as high at 5psi across my core at 18lbs. My current IAT temp is great IMO. I started at 120 and was at 160 or so @ 25lbs by the end of the 1/4 last night.
If I can get the time I'll toss on a gauge pre-IC and see how this core is performing.
Treadstone claims...
1469 CFM flow rate, 1000hp efficient, 1.5psi drop
07-14-2014, 10:02 AM
#206
I broke it! 
Managed to take my HG/head out Saturday. I just don’t think these tiny zero overlap cams can take the timing.
Blew it at 17* and 25psi. 50/50 water meth, IAT was under 160*, with the intercooler. Tune in the logs looked spot on. 11.0 AFR all through the run. Same tune up/boost as the night before where I was trapping 159. Had just installed cooler plugs in the morning went from a NGK7 to a autolite race 8 with the side gapped electrode. Blew it first pass. Plug looks like new, no signs of detonation on the plug or piston face.
Couple theories. Once I got the car home I noticed the lower radiator hose was worn through where it rubbed the crank pulley. I suppose this could have ruptured first, blew the coolant and then the head overheated and let loose.
I’d assume a more likely event was the HG blew, pressurized the **** out of the cooling system causing the hose to move up into the pulley taking it out. It was always within 2” of the pulley, but never noticed it touching and had it secured with some cable ties. Coolant was at 180* at the start of the pass. Just drove it all the way to the track too so I think I would have noticed if it was out of coolant.
Really stinks! I lucked out with that alum block 5.3 with 243 heads for $500. I managed to trash the head and the deck.
Pulled it yesterday. Going to try my spare 4.8 for the rest of this year at least.
Managed to take my HG/head out Saturday. I just don’t think these tiny zero overlap cams can take the timing.
Blew it at 17* and 25psi. 50/50 water meth, IAT was under 160*, with the intercooler. Tune in the logs looked spot on. 11.0 AFR all through the run. Same tune up/boost as the night before where I was trapping 159. Had just installed cooler plugs in the morning went from a NGK7 to a autolite race 8 with the side gapped electrode. Blew it first pass. Plug looks like new, no signs of detonation on the plug or piston face.
Couple theories. Once I got the car home I noticed the lower radiator hose was worn through where it rubbed the crank pulley. I suppose this could have ruptured first, blew the coolant and then the head overheated and let loose.
I’d assume a more likely event was the HG blew, pressurized the **** out of the cooling system causing the hose to move up into the pulley taking it out. It was always within 2” of the pulley, but never noticed it touching and had it secured with some cable ties. Coolant was at 180* at the start of the pass. Just drove it all the way to the track too so I think I would have noticed if it was out of coolant.
Really stinks! I lucked out with that alum block 5.3 with 243 heads for $500. I managed to trash the head and the deck.
Pulled it yesterday. Going to try my spare 4.8 for the rest of this year at least.
07-14-2014, 10:41 PM
#209
Same timing I've been running for awhile now 17*. I really dont' know if timing was the cause of this. I'd think there would be detonation signs if it was timing related. Looks like cylinder pressure was leaking. Possibly due to the china studs, or uneven head/deck surface.
These upclose pics show it looks like I've had CC leaks burrowing their way through the head and gasket for awhile now. I think one just finally made it all the way. I could be crazy, but I really don't feel I was detonating.
These upclose pics show it looks like I've had CC leaks burrowing their way through the head and gasket for awhile now. I think one just finally made it all the way. I could be crazy, but I really don't feel I was detonating.
07-15-2014, 08:56 AM
#214
LS1Tech Co-Founder
iTrader: (34)
Kurt did say via FB he had checked out the pics. Maybe you could take a close up of some of the damaged areas?
So would you be changing to different head studs or a different HG?
FWIW I've seen folks run 7's on E85 only, do you even need meth? [speaking 3rd-hand not an expert whatsoever]
So would you be changing to different head studs or a different HG?
FWIW I've seen folks run 7's on E85 only, do you even need meth? [speaking 3rd-hand not an expert whatsoever]
07-15-2014, 09:05 AM
#215
Kurt did say via FB he had checked out the pics. Maybe you could take a close up of some of the damaged areas?
So would you be changing to different head studs or a different HG?
FWIW I've seen folks run 7's on E85 only, do you even need meth? [speaking 3rd-hand not an expert whatsoever]
So would you be changing to different head studs or a different HG?
FWIW I've seen folks run 7's on E85 only, do you even need meth? [speaking 3rd-hand not an expert whatsoever]
) Had most of the parts laying around the shop from other cars, cost next to nothing to run it. Also from past experience the water helps keep everything nice and clean in the motor.
07-15-2014, 05:42 PM
#218
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Sucks this happened. You were really making strides with the 5.3, no doubt you would have dialed that in to run some mid-low 8's. The MPH was really showing the potential of the setup. Good luck with the 4.8 swap and look forward to updates.
07-15-2014, 07:51 PM
#219
Popped off the other head and it looked perfect. The lower 2 middle stud nuts did feel like they needed less tension than the others to break free. With as good as everything looks I'm really leaning toward the studs loosening up after many heat cycles and/or failing. The funky tigerstripe machine work can't be helping either... As with most things operator error is usually the biggest issue. Then we blame the parts and machining!
China studs would probably have been just fine if I retorqued them as I should have. Hard to get to those suckers though without removing the manifold on the passenger side. Who wants to do all that! extra work!
China studs would probably have been just fine if I retorqued them as I should have. Hard to get to those suckers though without removing the manifold on the passenger side. Who wants to do all that! extra work!