ae85 fiend Posted February 12, 2013 Author Share Posted February 12, 2013 Yup thats my budget build alright haha Sweet, so i'll pretty much start looking for some GZE pistons to suit then, should be a bit of a mission. I'm looking at decent cams, going down to the guy at Auckland Cams tomorrow to sus out getting some done and his opinion on what I should get too. Mhmm I guess i'll ask around anywhere/ everywhere I go haha, yeah I bought the rods off the guy that owns that crazy 500hp 7agte levin/ trueno whatever it is and forgot to ask but instead was asking about timing belts hahaha. Quote Link to comment Share on other sites More sharing options...
xsspeed Posted February 12, 2013 Share Posted February 12, 2013 Sounds like you have spoken to Barry (Bazda) then He knows these engines inside out so he's a good man to talk to Quote Link to comment Share on other sites More sharing options...
OldNathan Posted February 12, 2013 Share Posted February 12, 2013 I might show this to my neighbor and ask him. He knows his stuff. His 7agte is stock with headwork and cams. 8psi 270+hp and nice torque figures. Stock pistons and rods. 1 Quote Link to comment Share on other sites More sharing options...
ae85 fiend Posted February 12, 2013 Author Share Posted February 12, 2013 I might show this to my neighbor and ask him. He knows his stuff. His 7agte is stock with headwork and cams. 8psi 270+hp and nice torque figures. Stock pistons and rods. That would be sick, is it 20v as well? If you could get some details of what hes done/ head/ cams hes using, that would be amazingly helpful. Quote Link to comment Share on other sites More sharing options...
kpr Posted February 12, 2013 Share Posted February 12, 2013 bah, 11.5:1 works on turbo setup. ran 11.5 on my 16v 4age, 10psi boost, gull force10. couldn't really get anymore out of it though. but somewhere around 9:1 is good on pump gas, wont loose too much response over the 11.5 engine. but will start to get lazy when heading down into low 8's edit: and yeh the 8.9 ze pistons are the way to go Quote Link to comment Share on other sites More sharing options...
Toucan Posted February 12, 2013 Share Posted February 12, 2013 Think I remember seeing they can still be had new from toyota at a pretty reasonable price? Quote Link to comment Share on other sites More sharing options...
Rookie Posted February 12, 2013 Share Posted February 12, 2013 WOW so much misinformation in this thread, can a mod please clean it up? This whole thing comes down to dynamic compression ratio. You can run ~9:1 dynamic compression ratio on pump gas, any combination you use to achieve this will work. Here is a good read:linky Also don't go putting thick head gaskets in, all it does is fucks with the squish and usually makes detonation worse. 1 Quote Link to comment Share on other sites More sharing options...
Llama Posted February 12, 2013 Share Posted February 12, 2013 Learn something new errday. Quote Link to comment Share on other sites More sharing options...
flyingbrick Posted February 12, 2013 Share Posted February 12, 2013 Just get the 20v pistons skimmed the correct amount. Easy. Someone here must know the math. Fuck having an interference engine. Iv seen guys try start motors with cam timing so wrong it would have smashed valves instantly. Not worth the risk IMO. If you fit gze pistons then machine to clear the valves ( would be $$$$$) who knows what the cr will end up at afterward. With that said- forged pistons are surprisingly cheap Quote Link to comment Share on other sites More sharing options...
Rookie Posted February 12, 2013 Share Posted February 12, 2013 Sorry bud, but that is wrong. Skimming pistons is stupid, pistons need as much meat in them as you can get (within reason) to stop ring lands cracking and to distribute heat. Not to mention that 20v pistons were never designed to take the punishment of turbo engine. Just about every engine worth a pinch of salt is an interference engine so it isn't a problem, unless of course your cams are so big you have to do silly cam timing to make it work, then it is a problem. That said, I'm pretty sure that GZE pistons aren't interference even if they aren't fly cut. Edit: And Sentra makes fly cutting easy hahaha Quote Link to comment Share on other sites More sharing options...
Spencer Posted February 12, 2013 Share Posted February 12, 2013 I don't feel like arguing but, I don't think there was any conclusion after countless arguments over factory Toyota supercharged/turbo pistons verses NA pistons. It pretty much ended up that the ZE pistons are cast hypereutectic and the NA ones are probably the same thing. I can't find the argument thread any more though (probably a good thing it was gay) but anyway it is highly likely the 20v pistons are made in exactly the same fashion as the ZE ones which everyone runs big boost on. There are a shit load of +T Toyota engines that live on big boost on factory NA pistons Skimming these NA Toyota pistons is fine also, hey probably not best practice but it works. My friend in Taupo has skimmed down two sets now for turbo UZ builds with great results, one has been going over 5 years now with 20psi down its throat, plenty of others have done this also. Now by the time this guy gets the work done skimming his pistons he will have probably spent almost enough to buy some late model ZE pistons anyway, but if you can do the work yourself it's great bang for buck. I also agree on the interference thing, who cares? 1 Quote Link to comment Share on other sites More sharing options...
drftnmaz Posted February 12, 2013 Share Posted February 12, 2013 i run a n/a engine 9.5to1 and 20psi, its no drama, just need to have a tuner that knows what hes doing and use the fuel to cool pistons and starve off detonation (ie running 11to1 to 11.5to1 AFR's) running rich like this looses you stuff all power (like 3-6kw) and keeps things safe, then the only downside is how much timing you can chuck at it to make power, but if you're not chasing big power then a little bit up top is a minor trade-off for a super responsive fun car can you not mill the head chambers to bring compression to where you want it? adding 10cc to that volume will drop the static compression by about a point (im way to lazy to do calc's for you) Quote Link to comment Share on other sites More sharing options...
Rookie Posted February 12, 2013 Share Posted February 12, 2013 I don't really want to argue either, so I'll clarify my position. I wasn't talking about the manufacturing process, just the design, Turbo pistons usually have a lot thicker ring lands and have a more beefier construction to give them a bit more mass for dealing with heat. Now I'm not saying that 20v pistons aren't capable, because they are (in fact I was going to use silver top pistons in a black top), Just that they aren't perfectly suited to turboing, and I am just trying to give the best advice. Also, on skimming pistons, IMO all you are doing is making it weaker which isn't really what you want, again the best advice. 1uz pistons are heaps different to 20v pistons so not really apples and apples. Quote Link to comment Share on other sites More sharing options...
Truenotch Posted February 13, 2013 Share Posted February 13, 2013 Why not just run standard 7AFE pistons and a 16V head? Or any 16V piston and a 16V head for that matter... They work out to a good compression ratio for turbo and it would be hell cheap. Quote Link to comment Share on other sites More sharing options...
Rookie Posted February 13, 2013 Share Posted February 13, 2013 Because he has a 20v head and they are better for churbros because of the extra skirt area. Quote Link to comment Share on other sites More sharing options...
Yowzer Posted February 13, 2013 Share Posted February 13, 2013 WOW so much misinformation in this thread, can a mod please clean it up? This whole thing comes down to dynamic compression ratio. You can run ~9:1 dynamic compression ratio on pump gas, any combination you use to achieve this will work. Here is a good read:linky Also don't go putting thick head gaskets in, all it does is fucks with the squish and usually makes detonation worse. I wouldn't say misinformation, more just simplified information. This thread isn't really about calculating all your dynamic compessions and tuning effects and all that, which is why I didn't go into it earlier (and it sits on the borders of my knowledge). Without going to new cams and all that jazz a simple drop of 2-3 points in compression should give a pretty safe engine for boosty purposes. Sure the cams won't be ideal for a turbo, but it's being built on a budget. If he's building it for sweet sweet power then all that stuff does need to be taken into account, but I think we are starting to get a bit too techy for the initial question, which is how to drop the compression. Although I do like tech talk. It's all stuff I need to figure out soon anyway. Quote Link to comment Share on other sites More sharing options...
dohcturbo626 Posted February 13, 2013 Share Posted February 13, 2013 Fe DOHC is 10:1 factory don't be fool by these ppl telling you to drop to 8 or 9 nd cams are a big deal it dosnt't really matter. The big picture is that you have vavle to piston clearance next that u can tune the engine for the boost. Quote Link to comment Share on other sites More sharing options...
kpr Posted February 13, 2013 Share Posted February 13, 2013 Slap some 8.9ze pistons in, and do a skid. 1 Quote Link to comment Share on other sites More sharing options...
NaN Posted February 13, 2013 Share Posted February 13, 2013 NaN 2 Quote Link to comment Share on other sites More sharing options...
ae85 fiend Posted February 13, 2013 Author Share Posted February 13, 2013 Yeah, I was thinking about some sort of forged pistons, will definitely investigate further into to them now ( had a quick look when I was looking for conrods ) Lowest I could seem to find in NZ without going custom were 8.9/9.0 to one. Quote Link to comment Share on other sites More sharing options...
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