Motor blew up:(
Thread Starter
Racer
Joined: Oct 2012
Posts: 383
Likes: 1
From: Central Florida
Motor blew up:(
I've had a oil leak problem since day one. Well today I got a call after it's third two week stay at the shop, and number 3 and 5 lost compression. Needless to say this sucks, after looking at everything, they found the blower was making way more boost on the street then on the dyno. It peaked at 11lbs on the dyno, but after checking everything it was hitting 10lbs at only 3500rpms and peaked at 15 to 16lbs on the street. All it has is a A&A kit, LG headers, ported intake manifold and ported TB. I'm trying to decide to either to throw two new piston and rods in or go fully forged. The block and heads are fine, so I'm leaning towards just fixing this motor. Just looking to what you guys think is the best route. Thanks
Drifting
Joined: Jan 2009
Posts: 1,503
Likes: 1
From: Tennessee
Man that just doesn't sound right. I know that ECS uses a restrictor plate that if removed or comes out somehow boost will increase quite a bit. A and A does not use a restrictor plate as far as I know. I cannot understand how boost could increase so dramatically like that.
If it was me I would forge the internals rather than go back in with stock. The motor is already down a few more dollars for forged internals seems like good insurance if you plan on keeping the car boosted.
If it was me I would forge the internals rather than go back in with stock. The motor is already down a few more dollars for forged internals seems like good insurance if you plan on keeping the car boosted.
Thread Starter
Racer
Joined: Oct 2012
Posts: 383
Likes: 1
From: Central Florida
The data logging I had in the car showed 15lbs. I don't know how accurate that was, but they said in was way more than what it was on the dyno. What is the cost to just put a set of forged pistons and rods in. I don't plan on going any farther than 700whp.
Le Mans Master
Joined: Oct 2012
Posts: 9,366
Likes: 969
From: Out back
Since day one of what? Owning the car? Blower install? Need clarification please.
Initially, this to me sounds like a case of the dyno operators not having the load cell on the dyno calibrated properly. A change in load calibration on the rollers can wreak havoc on accuracy when trying to accurately dyno/tune a car. When you add the load imposed on the street (rolling resistance, aero load, gearing, hills, etc.) the entire behavior of the engine is different...something that a dyno can mimic when used by an operator familiar with this principle. You have a legit case to bring to the shop for them to supply a new motor. Their inexperience (or unfamiliarity) on their own equipment caused this failure. Plain and simple. When you say this to them, they'll ask...who told you that? Then they'll say I'm full of it. That's their denial setting in because they've been exposed. I have nothing to hide, nor anything to benefit from exposing their ineptitude. I've been dynoing cars for 12 years on numerous makes/models of dynos. I've seen more than most...and I just hate seeing incompetence from performance shops. Hell, I wouldn't be surprised if they try to blame it on your driving...
Initially, this to me sounds like a case of the dyno operators not having the load cell on the dyno calibrated properly. A change in load calibration on the rollers can wreak havoc on accuracy when trying to accurately dyno/tune a car. When you add the load imposed on the street (rolling resistance, aero load, gearing, hills, etc.) the entire behavior of the engine is different...something that a dyno can mimic when used by an operator familiar with this principle. You have a legit case to bring to the shop for them to supply a new motor. Their inexperience (or unfamiliarity) on their own equipment caused this failure. Plain and simple. When you say this to them, they'll ask...who told you that? Then they'll say I'm full of it. That's their denial setting in because they've been exposed. I have nothing to hide, nor anything to benefit from exposing their ineptitude. I've been dynoing cars for 12 years on numerous makes/models of dynos. I've seen more than most...and I just hate seeing incompetence from performance shops. Hell, I wouldn't be surprised if they try to blame it on your driving...
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Former Vendor
Joined: Oct 2007
Posts: 2,032
Likes: 6
From: longview tx
SI trim on that motor should be maybe 10-11 PSI MAX its just not enough blower to fill all that. If your cats were clogged up it would make sense though. 10 PSI at 3500 with that setup is a TON of PSI!!!
the Centri blower wont make more PSI on the street than on the DYNO. it is NOT load based so that also makes no sense.
If it were me or this was a customer of mine i would make sure he did a piston rod swap at a MIN. this was your weak link( pistons) are atleast gone and you can push her as hard as you want with that setup. The LS7 doesn't like that much PSI anyways so bad gas, a rev limiter a few times, your going to get that motor at those PSI levels every time.
the Centri blower wont make more PSI on the street than on the DYNO. it is NOT load based so that also makes no sense.
If it were me or this was a customer of mine i would make sure he did a piston rod swap at a MIN. this was your weak link( pistons) are atleast gone and you can push her as hard as you want with that setup. The LS7 doesn't like that much PSI anyways so bad gas, a rev limiter a few times, your going to get that motor at those PSI levels every time.
Melting Slicks
Joined: Apr 2007
Posts: 2,987
Likes: 16
From: Phoenix
I suspect plugged cats as well. As already mentioned, that blower and that pulley should put you nowhere near 15-16psi. The only reason possible for it hitting that boost is a restriction somewhere.
I'm spinning a T-trim with a 3.125" pulley and only get 12-13psi. I would just do forged rods and pistons. This will mean you have to have the rotating assembly balanced again though.
I'm spinning a T-trim with a 3.125" pulley and only get 12-13psi. I would just do forged rods and pistons. This will mean you have to have the rotating assembly balanced again though.
Instructor
Joined: Apr 2013
Posts: 236
Likes: 0
From: CT
I.e. the ls3 would be at 15-16 psi and the 7 would be at 12-13? I'm not saying with a t-trim and 3.125" pulley these numbers are accurate but just using them for comparison.
Le Mans Master
Joined: Dec 2007
Posts: 8,375
Likes: 97
From: Somewhere in the Mid 9's TX
Clogged cats could be it, but I wouldn't expect a hike that high. I had a similar issue on my SI LS3. If I can find the old dyno graphs, I can show you the difference with clogged vs unclogged. Boost spiked to the same levels, but just fell right off after earlier in the rpm band.
Melting Slicks
Joined: Mar 2007
Posts: 2,391
Likes: 23
From: Santa Barbara CA
How are they measuring boost to determine it was/is making 10 psi by 3500 rpm? Do you have a boost gauge in the car? Lots of unexplained details here.
In the end, a 3.4" pulley on an LS7 is fairly aggressive. Was this a pump gas build?
In the end, a 3.4" pulley on an LS7 is fairly aggressive. Was this a pump gas build?
