how many members have blown there motors at 5 psi
11-03-2006, 05:24 PM
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how many members have blown there motors at 5 psi hey guys im still buying parts for my turbo build but i really can t afford the new short block yet,so i was wondering just how many members have destroyed there motors at 5 psi max no more around 400 rwhp?i will add 6.0 317 heads though if that will help,i know it lowers the compression.so what u do u guys think?should i go for it?
11-03-2006, 05:28 PM
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Just keep the tune fat and keep her clean until the swap. plugs, oils, filters, wires... have a boost gauge and make your not going over your limit.
I dont think you'll have a problem... common sense really.
I dont think you'll have a problem... common sense really.
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11-03-2006, 07:00 PM
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Before we wrap this thread up, Alex, we should wait for RW99 to chime in... I'm almost sure it was over 5 psi, but I know he had BIG problems on low boost with a high mileage motor (Started crapping out on the dyno). He might have good advice.
Generally speaking, Jeremy knows how to tune with MOTOR SAFETY as the goal... But then again, you know he's ******* good as ****.
Generally speaking, Jeremy knows how to tune with MOTOR SAFETY as the goal... But then again, you know he's ******* good as ****.
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11-04-2006, 02:15 PM
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Hey, guys... I've been there but I'm not sure if there's much I can add to the conversation. The state of your shortblock is what it is, so to speak, so you're gonna have to go slowly into it and hope for the best.
Back in what, March? the kit was on the dyno and Nick at Newtech was starting out with moderate boost levels (7 psi or so... just WG spring) when it started to develop excess crankcase pressure. He did a full compression/leakdown on that stock motor and #7 wasn't holding up anymore. No question, Nick knows his **** on tuning, so that was never an issue.
Now this motor had been fine up to 80k or so using a higher compression NA setup with 5.3 stage II heads, mild cam, headers... 400 rwhp setup. The new setup went to AFR225's 72cc to get the compression down, but the bottom remained completely stock. Unfortunately, it just seems that #7 couldn't handle the new power, hence blowby. So I was left with rebuilding the stocker or getting a new motor.
I bit the bullet and went forged with an LS6 346 from A&A, and Nick and Josh swapped all the stuff onto it and that's what it's running now. It'll peak around 11 psi or so on the street, seems to love it. Very streetable.
If you've got the means to rebuild your stock motor then I think I'd just throw everything on and hope for the best... sounds like your tuner knows what he's doing, so start at 5 psi with a rich setup and take small steps up from there... monitoring crankcase pressure as you go and assuming that dips in power/torque while on the dyno may be an indicator that the motor's just not going to be able to take it. If you have a methanol kit, might as well set that up at the same time and increase your safety margin.
But if you've got limited resources or time for a rebuild, you might want to just wait for the low CR motor in your sig, which I assume will be forged and dished. It might save you a lot of labor $$ or time with a potentially fragile stock bottom end. Use this time to get everything else into readiness: critical stuff like the fuel system, alternator relocation setup, and the fricking fans.
I'll keep up on this thread and chime in if I can help... good luck.
Back in what, March? the kit was on the dyno and Nick at Newtech was starting out with moderate boost levels (7 psi or so... just WG spring) when it started to develop excess crankcase pressure. He did a full compression/leakdown on that stock motor and #7 wasn't holding up anymore. No question, Nick knows his **** on tuning, so that was never an issue.
Now this motor had been fine up to 80k or so using a higher compression NA setup with 5.3 stage II heads, mild cam, headers... 400 rwhp setup. The new setup went to AFR225's 72cc to get the compression down, but the bottom remained completely stock. Unfortunately, it just seems that #7 couldn't handle the new power, hence blowby. So I was left with rebuilding the stocker or getting a new motor.
I bit the bullet and went forged with an LS6 346 from A&A, and Nick and Josh swapped all the stuff onto it and that's what it's running now. It'll peak around 11 psi or so on the street, seems to love it. Very streetable.
If you've got the means to rebuild your stock motor then I think I'd just throw everything on and hope for the best... sounds like your tuner knows what he's doing, so start at 5 psi with a rich setup and take small steps up from there... monitoring crankcase pressure as you go and assuming that dips in power/torque while on the dyno may be an indicator that the motor's just not going to be able to take it. If you have a methanol kit, might as well set that up at the same time and increase your safety margin.
But if you've got limited resources or time for a rebuild, you might want to just wait for the low CR motor in your sig, which I assume will be forged and dished. It might save you a lot of labor $$ or time with a potentially fragile stock bottom end. Use this time to get everything else into readiness: critical stuff like the fuel system, alternator relocation setup, and the fricking fans.
I'll keep up on this thread and chime in if I can help... good luck.
11-04-2006, 02:42 PM
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I think you'll be fine at 5PSI. I was running this PSI for 4 months when I bought HP Tuners and discovered my mail order "turbo tune" was nothinig more than the stock VE table with a remapped idle and lowered spark advance! 
Even then I managed to not blow anything up. Thankfully I have been able to give her a decent tune now (and gain a $hitload of HP in the process).
I took some other steps to keep the engine happy (besides tuning), which I would strongly suggest to you if you're worried about this.
1. Upgrade the fuel system: I run a 255GPH Racetronix in-tank pump with a return line, 42lb injectors, Aeromotive boost referenced FPR and SpeedInc rails for added flow. This system is a bit overkill, but I like the fact my injectors are only running 68% duty cycle at WOT and high RPM. Better than running out of fuel!
2. Wideband. Definetly get a wideband. This will tell you when to get the hell off the gas if there is ever a doubt. I also have my tune set for a fat 11.1/1 AFR. The "optimal" is 11.6 or so, but I like to keep a bit of a buffer for unexpected spikes, etc.
3. Front Mount Intercooler. Even at 5PSI on a rear-mount turbo I was seeing IAT's of 130+ degrees. With the FMIC I've yet to see temps over 103 normally driving and 110 with back to back WOT blasts and no cool-down.
The 6.0 heads will help you too. They are supposed to lower the C:R a full point. I have a set in the house waiting to install.
Hope this helps.
Even then I managed to not blow anything up. Thankfully I have been able to give her a decent tune now (and gain a $hitload of HP in the process).I took some other steps to keep the engine happy (besides tuning), which I would strongly suggest to you if you're worried about this.
1. Upgrade the fuel system: I run a 255GPH Racetronix in-tank pump with a return line, 42lb injectors, Aeromotive boost referenced FPR and SpeedInc rails for added flow. This system is a bit overkill, but I like the fact my injectors are only running 68% duty cycle at WOT and high RPM. Better than running out of fuel!
2. Wideband. Definetly get a wideband. This will tell you when to get the hell off the gas if there is ever a doubt. I also have my tune set for a fat 11.1/1 AFR. The "optimal" is 11.6 or so, but I like to keep a bit of a buffer for unexpected spikes, etc.
3. Front Mount Intercooler. Even at 5PSI on a rear-mount turbo I was seeing IAT's of 130+ degrees. With the FMIC I've yet to see temps over 103 normally driving and 110 with back to back WOT blasts and no cool-down.
The 6.0 heads will help you too. They are supposed to lower the C:R a full point. I have a set in the house waiting to install.
Hope this helps.
11-06-2006, 03:04 PM
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I wasn't the wrench on this job, but don't they use a pressure gauge modified to fit in place of the oil cap? Once you're into the build, you'll stick a breather on there anyway. As for the PCV I honestly don't know on that one; I have a catch can but I don't know what sort of valve arrangement is now used. Lotsa guys on here can probably get you up to speed on EGR/PCV/AIR mods for FI.