Same question for you as well, can you cite some specific examples? I’m curious, as almost everything I’ve seen has been the opposite, and I think I’ve heard of maybe 1 or 2 cases of stock piston failure with just rod swap on a big turbo setup, compared to a ton of success stories from cars.
No, he’s running a 2.8l.
Jibbberjive sorry I suck at forums. I posted above a quoted comment. This is common. There is a big 2.7T shop that I used to help with… that has seen this almost everytime they attempted to build a bigger hp car with stock pistons.
Still let me say this again in the proper post
I have seen this on more then one occasion. Still I do suggest that we look more to the fact that the stock pistons are not just not breaking but there not properly supporting the requirements of the piston functions at these increased hp levels. Looking at this in a fashion of not so much is the piston material strong enough but is the supporting duties of the piston going to be up to the task of a higher hp limit. When you take into consideration all the other requirements of the pistons, I believe the would change
Thank you for all the help. I have 2-3 weeks to wait for coated pistons - otherwise everything else is ready.
I’m aware of your previous relationship with VAST and current relationship with JHM, do you care to share more specific info, like specific numbers on approx how many failures you’ve seen, and/or what hp level/turbos? Like I said, I’m curious because of all of the successful counter examples of cars in the 500-600whp range on stock pistons with zero issues, so I’m hoping for some specifics rather than vague inferences that “something happened” often. If there are a ton of failures that just aren’t documented on the forums, then it becomes a case of having to weigh the failure rate at the intended power level vs the success rate.
And as far as the other design considerations of the piston outside of the ultimate yield strength (or whatever), where, specifically, do you see that the stock pistons fall short? Like I said, I’m curious to the specifics rather than generalities, as there are more than a few stock piston’d 500-600whp cars with zero issues of blow-by, overly exaggerated oil pressure, or the valves hitting the pistons because of the reliefs. I agree, it’s nice for a part to be designed for a specific application, but design application doesn’t necessarily dictate how a part will work outside of it’s intended design application.
read between the lines. Not something he can/wants to talk about.
Anyway, who does a 600 whp build but tries to save $1000 on pistons after spending $1000 on rods, and another $10,000+ on the rest of the build? Seems weird. Tantamount to getting your 4.2 car supercharged, but leaving the stock downpipes and tiny catback on to save a few bucks.
I can read between the lines and think that VAST blew up 10+ stock piston motors, or I could read between the lines and think they blew up 2. Not much info to go on other than vague inferences, and the difference between those two scenarios is huge. Circumstance also plays a huge role as well, for example, the AMD car that blew up when they tried to push 40psi or whatever was running fine on stock pistons at over 600whp IIRC for like a year or two before they tried to push it further and blew it up. If it was a similar case with VAST, JHM or whomever he’s inferring, and the failure(s) happened when pushing the limits on a huge turbo setup, then that’s worth noting, as someone who is pusing Tials to 500-600whp should still be fine, just like all of the other setups running stock pistons in that power range.
If it’s something he can’t talk about, that’s one thing and that’s fine, but if it’s something that he doesn’t want to talk about, then he shouldn’t put tidbits of info out there that can be interpreted a lot of different ways without more specific info. Pretty much everyone on this site (except NotoriousVR apparently ;D) knows who he is and what affiliations he’s had, so there’s no need to be cryptic just for the sake of being aloof.
As for why someone would put stock pistons in a bigger turbo build, there are a lot of reasons, and yes, money is one of them ($1000 on a $10k build is 10% savings, that’s not insignificant, and that’s just the savings for the hardware, you also save some machining cost), though money is far from the only reason. If you care to read my personal reasons for choosing to use the stock pistons over other options, check out the first post in my AZ build thread.
People get nervous about building motors. While it’s not rocket science, it’s not simple and the stock pistons can handle a good bit of power (even if new forged ones are a better option). I’ve seen builders mess it up, machine shops mess it up, parts fail, etc that have caused thousands and thousands of dollars of problems that weren’t the customer’s fault. Sadly, the customer will almost never see that money again
Well, he could just stay silent jibberjive. How about that? CV has no obligation to give you or anyone any information, whether he’s able to or not.
If he wants to share his opinion, and it’s too concise for you to write an engineering paper with the information, and he’s clearly not going any further with it, you now have 2 decisions:
- take the information as is, knowing that it comes from someone who has seen/done more with the S4/RS4 than the rest of the braintrust on audizine combined
- dispute the opinion and look elsewhere for an opinion that lines more up with what you chose to do
It’s pretty simple. Just because his opinion is not yours, doesn’t mean either one of you are wrong. It just means you don’t agree on this particular principle.
I’m simply trying to have a discussion with a guy who has more experience than myself. And you’re responding for him. I’m not trying to argue/dispute/goad anybody into anything they don’t want to do. If he says he doesn’t want to share any more info (or simply doesn’t share any more info), then so be it. From what he has shared so far, not much has been said that we can derive much info from, considering we know nothing of the details nor how many cars had problems.
BS, I run stock pistons, I have built 20 plus 2.7 varients with stock pistons and just rods with a quality rebuild and they hold up fine. They are a mahle forged piston and are leaps and bounds better quality and metallurgical properties than most after market like JE and diamond.
You sure do pump out a lot of fucking misinformation.
lol I’m not responding for him. He responded already on the previous page. I just saw that you asking the same question again wasn’t going to get (further) answered. I’ve seen this happen before.
Here’s CV’s post in case you missed it…
You replied for him 5 mins after my first post to him (post #24). I haven’t asked him the same thing more than that 1 time, I’ve been replying to your attempts to answer for him. He can choose to reply (or not) for himself, and clarify (or not) the stuff that he vaguely refers to so that it might be beneficial rather than just a “I’ve seen some stock pistons fail” and “we should consider the piston design cause they are not properly supporting the requirements of the piston functions.” If he wants to make the info that he knows useful to the forums, let him; if not, you don’t need to try to answer for him. This conversation that I’m trying to have has nothing to do with you.
- 3 hours does not equal 5 minutes
- you asked him the same question twice (after someone else already had) and got the same answer…then before you asked a third time (fourth time overall) I tried to say what I was seeing. Pretty plain.
You keep focusing on catastrophic failures when that’s not what he alluded to. I believe CV is saying the pistons may survive in that environment, but may not be the best choice for these big power builds (this thread is about a 700whp/800 crank hp build remember). To me that’s what he’s pointing out…not warning you that your pistons are going to flare the skirts and fuck things up. He’s saying you’re leaving a part in that should be improved upon.
So go nuts. Ask away. I’d like to hear more detail on the answer too. I just get the distinct impression we’re not going to hear it. CV has a history of avoiding discussions like this on the forums for a number of reasons, one of which is to not spoon feed the competition (by posting everything publicly) some of the information he has worked hard to learn.
- 7:33PM and 7:38PM = literally 5 mins
- My first (and only) post to him was post #24. Look at who I quoted in my other posts to see who I was talking to previously.
I’m not focusing only on catastrophic failure, my post specifically asks about what “supporting” piston roles he feels are inadequate with the stock pistons compared to the aftermarket options for the B5. Funny, I also have the distinct impression that he’s not going to reply, now that it’s been unnecessarily blown up into a big deal. However, I’d definitely like more info if he’s willing, because all we have otherwise is virtually a completely one-sided successful track record for running stock pistons with upgraded rods at the power level detailed in the OP. More data points are always welcome.
lol damn…I was looking at the time on the quoted post, not your actual post. My bad.
anyway, don’t blame this ‘getting blown up’ (a bit dramatic, isn’t it?) on not getting an answer. If I’m wrong and he was going to lay his information all out there, that’s awesome…and he still will.
If he never was, he won’t.
I just have a bit more experience trying to drag information out of the Count…it’s tough! Again, by all means, continue to ask your question. PM him, post in this thread. I just offered my opinion on what was happening. I’ll try not to as it pertains to helping you B5 guys in dealing with the count. Didn’t work very well when trying to give advice to Notorious on the matter, and it appears to be upsetting you here.
Just PM him… People are often a lot more willing to talk about things that they don’t necessarily want to say on a public board. The most useful information I get from forums is rarely what’s publicly posted.
that’s because you’re used to audizine’s 3.0 A4 section lol 
[quote=“sakimano,post:36,topic:3407”]
Let this be your last reply to this tangent then. As like I said, I’m not trying to get info from you, and if Count doesn’t want to share his, that’s his prerogative.
I’m not looking for any information that he wouldn’t want to say on a public board. My personal engine is already built, so the information isn’t necessarily going to benefit me with build decisions, rather it would need to be posted publicly to benefit future engine builders. I was hoping he’d share the failures he’s seen, so we can add them to the data set that up til now pretty much unanimously says that the stock pistons are very well suited for the power level the OP was inquiring about.
[quote=jibberjive]the data set that up til now pretty much unanimously says that the stock pistons are very well suited for the power level the OP was inquiring about.
[/quote]
Really? The OP said this a few times:
I have to ask…how many B5 S4s have ever even made 800 crank hp (maybe 650-700 whp)? And how many of them made that power level (succesfully) on stock pistons? Honest questions…I was under the impression that 650-700 whp (800 crank hp) was not exactly ‘common’…so this ‘data set’ you are referencing might be smaller than something from which to reliably draw a conclusion, no?