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The mkiv Supra Owners Club

700hp. Pistons only, or rods?


Noz
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7 hours ago, Burna said:

No I meant the actual wear that has already happened on the engine parts on an old tired engine. The tune wasn't the cause of my problems, ring lands going on stock pistons are becoming more and more common now. Luckily for me that failure caused a strip down of my engine, which then showed that the big end bearings had come to the end of their life anyway, beyond in fact, but caught just in time. We reckon if they had done one more hard run across Europe I could have span a shell! Which would have caused a lot more damaged, so I see it has a good thing my piston went when it did!

A single turbo on a stock UK spec ecu will not kill a stock engine mate, a dyno run showed it would run ok fueling wise etc... Mine had a dyno run on 264 cams, which showed it to just start leaning out, but the cams were only fitted just prior to the trip down to SRD. What is true is that it doesn't drive great on a stock ECU, as in driveability, not the fuelling etc.. But after a proper aftermarket ECU, and a good mapper, the car now drives like a stock car, but on a single turbo. It's drives so smooth and is easy to drive with no lag 🙂

It's the extra load of more boost or a single turbo on original parts, that have seen thousands of heat cycles and revolutions over the many years these cars have done now, that will show up the weaknesses and will cause a failure to a stock original unopened engine.

Ah, ok. I was under the impression you melted yours running the stock UK-Spec ECU lol. My bad. 

After speaking with Lee, he said that the AFRs were a big cause for concern, not even under high load when running the stock UK-Spec ECU, etc. 

Going back to the OP's question, I'll reiterate that going forged isn't necessary, IMO. A refresh would put the engine in good stead for 700bhp if anyone has concerns about brittle rings. 

Personally, I'll be running mine on similar power eventually at the wheels and will only open the engine up if a ring or something else let's go. 

 

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12 hours ago, Big Supes said:

Ah, ok. I was under the impression you melted yours running the stock UK-Spec ECU lol. My bad. 

After speaking with Lee, he said that the AFRs were a big cause for concern, not even under high load when running the stock UK-Spec ECU, etc. 

Going back to the OP's question, I'll reiterate that going forged isn't necessary, IMO. A refresh would put the engine in good stead for 700bhp if anyone has concerns about brittle rings. 

Personally, I'll be running mine on similar power eventually at the wheels and will only open the engine up if a ring or something else let's go. 

 

The AFR's aren't perfect on a stock ECU, but it's passable I'd say, but not a long term solution for sure!

Not brittle rings mate, the ring lands. But hey, everyones choices are different, and so is peoples advice. I was the same as you, run it until it blows lol 

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I also fell foul of this. I decided that i didnt need to do pistons, but did rods for safety. And now wish i did pistons but also wish i did mains or a girdle kit. At the time money was an issue, but having realised what ive spent on the rest of the car, i should have done the engine propperly. But you live and learn

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4 hours ago, Andy Ven said:

I also fell foul of this. I decided that i didnt need to do pistons, but did rods for safety. And now wish i did pistons but also wish i did mains or a girdle kit. At the time money was an issue, but having realised what ive spent on the rest of the car, i should have done the engine propperly. But you live and learn

If it's still running well, I'd not beat yourself up about it mate.

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Its running fine. I was surprised how well the stock pistons and rings measured up after 230k kilometers on them. Still within factory tolerences. Only time will tell how it will fair with more boost. Going to 25 psi, but i will be using a soft fuel cut limiter instead of any type of hard cut to give it as easy life as possible. 

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