| Author | Topic |
|---|
Location:
Perth
Registered:
January 2005
|
|
Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Sun, 24 July 2005 12:14
|
 |
Hi,
I finally got my AW11-GZE up and running with an SC14. It is running custom engine management and 18psi of boost (yes I know that sounds very high  ).
I am slightly concerned about the reliability of the pistons.
I will probably get some forged pistons in the next couple of weeks anyway, but can somebody comment on using the 8.0:1 ZE pistons at this level of boost. As far as I am aware, I don't know ANYBODY who has run this much boost with an SC14, which is actually not spinning the SC any faster than a 168mm/120mm pulley combo with the SC12......And if it seems to good to be true (acceleration is so good) then this has surely got to end in tears!
Cheers, Nick
car details and moderate boost tuning run video here: -
http://www.e-wire.net.au/~nrparker/MR2/NewEngine/n ew_engine.htm
|
|
|
Location:
Bundaberg, Qld.
Registered:
May 2002
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Sun, 24 July 2005 12:22
|
|
the aw11 gze pistons are forged and will handle that amount of boost with out any dramas.
its more in the tuning that you should be worried about. 
|
|
|
Location:
Perth
Registered:
January 2005
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Sun, 24 July 2005 12:34
|
|
Hi Feral,
I agree tuning is ABSOLUTELY critical! I have tuned the car with a wideband O2 (damn handy) and basically run 0.85 lambda everywhere above atmospheric pressure, and spark advance is down to 20 degrees at 18psi. And this surprisingly works on 95 octane. Though I'll be using 98 for safety. Its not quite optimal for power, but I'm just playing it safe for now.
I think I can keep it from detonating BUT its the mechanical strength of the pistons that I'm worried about.
Regards, Nick
|
|
|
Location:
Montrose, VIC
Registered:
May 2002
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Sun, 24 July 2005 13:20
|
|
|
What's it putting out? Or haven't you dyno'd it yet?
|
|
|
Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Sun, 24 July 2005 20:29
|
|
Heya Nick,
i think the mechanical strenth of most pistons is fine... it's detonation that is the death of them... even cast pistons are often fine, but the difference is that the forged tc ones are tougher and resists damage from detonation better than cast...
and it is mainly the ring lands that will fail before anything else (or rings), as the crown of the pistons is quite solid... the GZE pistons look like a nice design...
start very safe on timing, get the AFR's correct (.85 sound squite rich enough to start), then feed in a little more timing... there is definitely heaps to be gained from more timing, but there is the dange of blowing things apart with too much.... more power.... or safer pistons
have fun n good luck!!
Cya, Stewart
|
|
|
Location:
Perth
Registered:
January 2005
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Mon, 25 July 2005 02:13
|
|
Hi,
I haven't dynoed it yet mrshin, but its pulls lots harder than my
old AW11 with 11.5psi, no cat and HKS pod filter which I estimate was atleast around 170hp crank.
I'm running 18psi with the original cat and exhaust which I'm sure is crippling it a bit the moment. Also, I still need more fuelling before I can start pushing it. The 365cc's would be bang on 90% duty at 6000rpm (I've only revved to 5500rpm because of this), even 440cc's would be at 93% duty at 7500rpm, 0.85 lambda which is barely ok. Maybe I should start looking at some 550s......
Cheers, Nick
|
|
|
Location:
Adelaide
Registered:
July 2002
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Wed, 27 July 2005 23:09
|
|
|
Hey Nick. I had a piston/ring failure on a 4agze SC14 2 weeks ago and I was only running around 14psi. I guess there is an ecception to every rule. Mind you, I was towing a 500kg trailer and overtaking a 50m road train at the time.
|
|
|
Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Wed, 27 July 2005 23:13
|
|
|
Irish, did you hear any abnormal noises.. like pinging/tinkling in the leadup? or it was never detected?
|
|
|
Location:
Adelaide
Registered:
July 2002
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Thu, 28 July 2005 00:19
|
|
|
Nah, no det. I presume that it was just too much boost. I had confirmed that I had the fuel for the boost. It was a warm day and I had been on boost for 1000km continuously (no bypass valve). I was not looking at the time but my estimated speed was 160-180kmph. I guess I had a little too much faith in toyota over-engineering. Anyway, it gives me an excuse to build a good engine.
|
|
|
Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Thu, 28 July 2005 05:55
|
|
|
can you cnfirm if it was the piston ring lands or the actual rings that let go first?
|
|
|
Location:
Adelaide
Registered:
July 2002
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Tue, 02 August 2005 08:59
|
|
|
I won't be able to confirm what broke till I tear down the motor.
|
|
|
Location:
sydney
Registered:
November 2003
|
|
Re: Piston strength - I run an SC14 at 18psi on 4AGZE pistons
|
Tue, 02 August 2005 09:18
|
|
| nick.parker wrote on Sun, 24 July 2005 22:14 |
18psi of boost (yes I know that sounds very high ).
I am slightly concerned about the reliability of the pistons.
|
Well, mine ran 22.5psi with gze pistons and it didnt miss a beat
It has nothing to do with boost but with the tuning as has already been said.
My brothers car ran 30 psi on just forged pistons and held together without any problems.
A good computer and tune will be your best friend
|
|
|
