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vegasviper
Guest
8# ROE S/C or 300 shot NX. Can the new engine handle it?????????
b3rndtt0ast
Enthusiast
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300 dry or wet on a stock block n bottem end pushing it.
8lbs of boost on a stock block and bottem end pushing it.
8lbs of boost on a stock block and bottem end pushing it.
onerareviper
Enthusiast
Sean would know for sure, but after reading though all the Roe SC'er posts I have yet to see a cast piston car using the smaller 8# pulley. I know it is not recommended.
Vipermed 97.01
Enthusiast
I can tell you this,we installed one on a 01 and recomended to the customer that he waited until we rebuilt the motor w/forged.Customer decided against our advise to run with it.and we would rebuild another time when he could spair the down time.we recieved the car back 2 months later not due to problems but the customer was going out of the country for awhile and wanted us to go through it.Now this person is extremely ******* his car and told me that he did notice some load detonation as the weather warmed up but other than that it was great.I personally tore down the motor and to my surprize the pistons were spotless and that was with audible detonation,that being said this is not something that i recommend but i will tell you that the customer had put 4900 problem free HARD miles on the car
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vegasviper
Guest
Great news Vipermed. On my forged engine i ran more 300 shot of NX than you can believe, but i feel limited with the new cast cast engine. I would like to run the 8# pulley soon, so keep the feedback coming. I have heared that other tuners have run more boost with cast piston 2000+ engines, is it the fact that it is a diffrenet blower set up than my ROE S/C??????????
I need lot of feed back
Thanks
Steve
I need lot of feed back
Thanks
Steve
GASDOC
Enthusiast
So what's the worst thing that could happen with the 8# pulley and cast pistons?
It must be pretty expensive changing to forged pistons ,especially after reading VIPERMED's statement of no damage seen after several thousand hard miles.
Other than the pulley what else needs to be changed??
It must be pretty expensive changing to forged pistons ,especially after reading VIPERMED's statement of no damage seen after several thousand hard miles.
Other than the pulley what else needs to be changed??
treynor
Enthusiast
> So what's the worst thing that could happen with the 8# pulley and cast pistons?
In general, tuning can make higher boost levels "safe" for cast-piston cars by avoiding detonation and keeping cylinder temps safe.
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In general, tuning can make higher boost levels "safe" for cast-piston cars by avoiding detonation and keeping cylinder temps safe.
BigCarrot
Enthusiast
MMMMMMMMM, piston soup! Yuuummy! lol
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vegasviper
Guest
Trynor, ive seen lots of engines end up that way, some are mine, But was that picture you posted due to a 8#pulley on a cast piston or was it a non related engine blow up?
BigCarrot
Enthusiast
I blew my 01 up on a 200 shot of nitrous. 9 of 10 pistons were shot. I literally had compression in ONE back cylinder! The ring lands are too high on the cast creampuff pistons. My engine didn't look like the soup above, but it was nasty. Just throw in some forged pistons and forget it!
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vegasviper
Guest
BigCarrot, was it NX wet shot or dry 200 shot?
BigCarrot
Enthusiast
NX wet. I've had NX kits on my cars since before they named themselves that. (college friend works for em) Great kits, no idea what happened.
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vegasviper
Guest
Was there any holes in pistons or any broken pistons showing lean condition
treynor
Enthusiast
> Treynor, ive seen lots of engines end up that way, some are mine,
> But was that picture you posted due to a 8#pulley on a cast piston [...]?
No, absolutely not. The picture I posted was the aftermath of shifting an Acura RSX Type S from 6000 RPM in 5th to 2nd. Turns out those little 4-bangers don't rev to 15K... even with VTEC.
I -assume- that the main failure mode for a creampuff with too much boost would be detonation and subsequent damaged pistons, especially the aforementioned ring lands. However, IANST. I do know that Doug Levin has a bunch of 700+ RWHP creampuff cars running around out there, so it can be done...
> But was that picture you posted due to a 8#pulley on a cast piston [...]?
No, absolutely not. The picture I posted was the aftermath of shifting an Acura RSX Type S from 6000 RPM in 5th to 2nd. Turns out those little 4-bangers don't rev to 15K... even with VTEC.
I -assume- that the main failure mode for a creampuff with too much boost would be detonation and subsequent damaged pistons, especially the aforementioned ring lands. However, IANST. I do know that Doug Levin has a bunch of 700+ RWHP creampuff cars running around out there, so it can be done...
Torquemonster
Enthusiast
There's several 1000+hp engines running around very successfully on cast hypertectic pistons. They do not like detonation but as Ben says - if the timing and air/fuel are right that should not be an issue on an EFI car.
The high top ring is an issue for high boost. I don't consider 8lbs high boost - but a lot comes down to cylinder pressure - 8lb boost plus high compression plus short duration/fast action cam = lots of cylinder pressure - that's the real important thing to know - what is the cylinder pressure at full boost - that is what the top ring has to deal with. It'd safely run 8lbs with a big cam.... but a stock cam may be an issue - Sean can probably advise on this.
The high top ring is an issue for high boost. I don't consider 8lbs high boost - but a lot comes down to cylinder pressure - 8lb boost plus high compression plus short duration/fast action cam = lots of cylinder pressure - that's the real important thing to know - what is the cylinder pressure at full boost - that is what the top ring has to deal with. It'd safely run 8lbs with a big cam.... but a stock cam may be an issue - Sean can probably advise on this.
During the development of the Supercharger kit, we consulted with Mahle, the stock piston manufacturer. The engineer I spoke with, who was familiar with the 2000 and newer Viper piston, recommended we not exceed 5 psi for an extended duration in order to help ensure piston reliability. Because the twin screw style compressor makes boost from idle and many areas of the country can only get a maximum of 91 octane, we chose to take his advice.
As others have said, it's not only the material the piston is made of (they're just eutectic, not even the stronger hyper-eutectic), it's also the proximity of the top ring land to the top of the piston. The earlier pistons had more material above the top ring and were forged.
Regards,
Sean
As others have said, it's not only the material the piston is made of (they're just eutectic, not even the stronger hyper-eutectic), it's also the proximity of the top ring land to the top of the piston. The earlier pistons had more material above the top ring and were forged.
Regards,
Sean
Marc Lublin
Enthusiast
Vipermed,
How did the rod bearings look, I'm sure they must have been worn from detonation.
How did the rod bearings look, I'm sure they must have been worn from detonation.
BigCarrot
Enthusiast
My engine had no holes in the pistons, but the ring lands were busted on several of them. I guess it had to have run lean, but I can't figure out how or why. Ahhhh, the mysteries of trashing a $10k engine!
Torquemonster
Enthusiast
Thanks for that insight Sean - I'd just assumed the pistons were a higher grade than that..... so DC were too tight to run hypereutectic pistons - I can't believe it - that *****! I'd be sticking to 5lbs too....
Gerald
Enthusiast
BigCarrot,
Holy cow!! How'd you blow your engine?? just stock use?? I can't imagine being behind the wheel and the engine blowing! YIKES!
BigCarrot
Enthusiast
BigCarrot,
Holy cow!! How'd you blow your engine?? just stock use?? I can't imagine being behind the wheel and the engine blowing! YIKES!
Nitrous! It SUCKED! I was showing off for a chick too! I hit the spray, and it blew big! Flames came from the NACA duct and WAY out the tailpipes too, from what the guy behind me said. It sorta cranked, but it sounded like a box of rocks, so I killed it and tried to glide into a parking lot. The girl with me asked why I didn't just start it up and drive it there. We didn't work out! lol
