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Location:
cebu city, philippines
Registered:
September 2004
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how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 05:22
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need you inputs guys, thanks. 
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Location:
Victoria
Registered:
May 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 05:44
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7.56345324psi
and thats an approximate, my friend ran 7.5834234 and the rod melted
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how long is a piece of string, im sure it would hold lots if ur tuning was spot on...
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Location:
Adelaide
Registered:
July 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 09:52
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14.7psi (atmospheric)
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Location:
Adelaide
Registered:
May 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 10:16
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Massive boost pressures (>30psi) will not worry a conrod in the slightest. Rex willing to bet a Conrod will take a few thousand psi of compressive load with little problem. Far more than you can create with any turbo.
Welcome OldCorollas to give an actual numerical arguement, he is wise.
Failure comes from two other primary forces in the motor.
- Extensive inertial load, when the piston is slowed towards and accelerated away from TDC on the exhaust stroke.
- Extreme cylinder pressure due to uncontrolled early combustion, knocking, pinging, pre-ignition or whatever you want to call it.
Super Rex
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Location:
Rosanna, Melb
Registered:
June 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 14:30
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What Rex said.
Basically its high RPM or pinging that will kill your rods. From what I have read on here, I think 7AFE rods are at there limit around 7500RPM. And a good tune and good fuel will prevent pinging.
The amount of boost run wont affect the rods.
Hen
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I Supported Toymods
Location:
Wollongong, NSW
Registered:
December 2003
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Re: how much boost can a stock 7afe rod take SAFELY???
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Thu, 31 March 2005 23:20
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That's interesting. All the evidence I've seen (mostly from this forum) seems to point at the 7A's conrods inability to carry more than about 7psi of boost.
*searches back through tech forum*
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Location:
Madrid - Spain
Registered:
August 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Fri, 01 April 2005 04:07
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Additional combustion pressure (due to turbo) will relieve the tensile loads on the rod at high RPM. This will be better for the fatigue life of the part.
Unfortunately extra boost will run a higher chance of detonating, which puts high compression loads into the rod.
So provided that the tuner knows what he/she is doing and you have a fair margin on detonation, there shouldn't be a problem. Some "fixes" that would help prevent detonation are a good intercooler and/or water/methanol injection.
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Location:
Redbank Plains,near Ipswi...
Registered:
May 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Fri, 01 April 2005 13:06
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can vouch for stock 7A rods failing at high revs. we have a much better "stock" rod that is fitted for race use. these routinely work at 8000rpm. have never had a turbo one, so can't comment there. in general however, rods dont fail, their bolts do. the 7a has rather thin thru bolts, not splined bolts like 4ag etc. email me at work if you want more info. roadandtrack@hypermax.net.au
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Location:
cebu city, philippines
Registered:
September 2004
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Re: how much boost can a stock 7afe rod take SAFELY???
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Fri, 01 April 2005 14:45
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| TerryOBeirne wrote on Fri, 01 April 2005 23:06 |
can vouch for stock 7A rods failing at high revs. we have a much better "stock" rod that is fitted for race use. these routinely work at 8000rpm. have never had a turbo one, so can't comment there. in general however, rods dont fail, their bolts do. the 7a has rather thin thru bolts, not splined bolts like 4ag etc. email me at work if you want more info. roadandtrack@hypermax.net.au
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do you make and sell these 7a rods?
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Location:
Redbank Plains,near Ipswi...
Registered:
May 2002
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Re: how much boost can a stock 7afe rod take SAFELY???
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Sun, 03 April 2005 04:13
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yep, uprated rods are $704/ set of 4. these are machined, shot-peened, new ARP bolts and ready to fit. you have to advise if you have 19 or 20mm piston pins. as I said in my posting, best to email me at work and keep the commerical stuff off this forum. thanks a lot
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: how much boost can a stock 7afe rod take SAFELY???
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Sun, 03 April 2005 06:48
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yeah, majority of rods fail by tension, not compression... tension failure is from fatigue (of sorts.. low or high cycle depending how much you over rev it), and snapping throttle shut at high rpm, or over-revving on down shift is the worst as it doubles the number of high tension events on the rod (usually there is ignited mixture pusing down, but with closed throttle high rpm, the power stroke is now major vacuum stroke!)
rods are usually pretty strong in compression, and it would take a pretty massive force to cause a rod to bend from a compressive force. not saying it can't, just that with decent tuning and sensible revs, there's no reason you can't put a lot of force thru any rod...
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