i have been offered a set of hypereutectic pistons ranging from 7.5:1 to 9.5:1 compression ratio, at trade prices. what would you guys recommend to handle 20psi, and do you think that the hyp. piston would be able to cope with that amount of boost? obviously the lower the compression piston, the easier it can handle the boost, but i don't want to lose to much of the low rpm torque. i was thinking around 8.0:1, but i need other opinions.
i have or will have all the extra mods to handle the boost, ie bar & plate intercooler, fuel system, shot peen rods, gear box, programmable ecu, etc.
i have been told that i'd need forgies, but i don't think the know too much about the ford's strength's and weaknesses.
Well, with file-fit rings, you should be slipping comfortably under AUD$450. Otherwise, it's not really "trade".
Hypers are plenty strong enough for the boost most people will actually generate. They require less cold clearance than a forgie, so longer engine life and better warm-up. The main benefit of a forged piston is that it will deform rather than shatter, in initial failure.
I'll stir the pot by saying that most people who barrack for forgies either bought them while uninformed, or are dreaming about their engine's actual output. Unless you're going to be running alcohol and a blower, why worry?
Have you canvassed opinions on anything like turboford.org? At 20PSI I can see you having intercooling issues way before any other problems. This is a huge boost.
intercooling shouldn't be a problem as i've picked up a PWR VL-T 600x300x75 bar and plate cooler. i would like around 320rw kws, but it doesn't necessarily mean i'd get that.
i spoke to a couple of the guys at turboford.org in chat, but the really couldn't help me too much as it being an aussie ford engine related question, in a U.S. site.
im talking to Kyle (aka 6BOOST from PF) tonight to hopefully clear the air about the strength of the hyp's.
i was told be my mechanic that the hyper would be no good for more than 8psi, so i also asked kyle his thoughts on them... this is his reply
____________________________________________________
The hyperutectics will handle 700-800hp, I only had them in my falcon, so does anthony briggs 9 sec cortina. I would stick to at least 8:1, preferably 8.5:1.
I would also recommend putting in mineral oil of very good quality for the first 500klm's, and I would advise to thrash the ass off the car as much as physically possible, the only thing I would do is set the rev limit about 500rpm lower than final, say 5000-5200rpm, this will not hurt the engine, and will bed the rings in the best. My car was on the dyno and getting the shit ringed out of it 10min after it was going properly, but don't forget to change the oil at 50, 200, and 500klms, the last being to Mobil 1 synthetic.
You mechanic is a toss, to say the least, and I would find a new one, LITERALLY. I GARANTEE that these pistons will handle at least 700hp, as long as it is tuned correctly.
i hope this has answered a few questions for other users, it was a little late for me as i have decided to post-pone the turbo set-up and go for a shot of nitrous until funds become available again.
Exactly!!! TUNNING is just as important. Even quality pistons will fail with bad tunning.Pays to be safe on timming advance fuel curve etc..Detonation kills any engine especially f/induction...
A good prodramable ecu is the answer!!!! Pay attention to rod,head bolts, arp etc...
__________________
Don't be afraid to try something new. Remember, amateurs built the Ark...Professionals built the Titanic!
.
Tuned & maintained by "Peppertree Perfmormance". Dart block, Scat 4340 steel crank, Custom C.P pistons.Oliver rods.. Mal Wood twin plate clutch.. Twin SC61/2's,482 rwkw/ 645 rwhp..
Passengers, myocardial infarction material..
R.I.P Possum...
what the hell kind of gear box are you going to run to handle a 4lt with 20psi? My plans are gonna be dangerous to my box at about 10psi Max before I'll need a hardcore tremec or drag auto box.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.