Interviews with Chief Engineer Tetsuya Tada

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A70TTR

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I'd own one as a stock DD.

But, we're so far OT now that Guff/Supra 93 may sell me into 3rd world slavery lol




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SupraStew85

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The general consensus with the supra owners that I know is a properly built and maintained 7m can be tough.
Although not quite the same I have pushed a 34 year old 5m to absolute living hell for 5 years and 40,000 miles and it has never ever let me down... and I'm not talking like oh wow he took his car to 6000rpm. I mean constant redline pulls/revlimiter/general shenanigans. Theres only so many ways you can make 160hp fun lol.
 

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I wrote a more in depth comment on why they're meh, but it's such a dead horse that I deleted it. Basically, the issue isn't just the head gasket and improper stud tq values; Toyota used weak aluminum that was prone to annealing, as well as engineering a head bolt seating area thinner than it should have been. So what happens in many cases is that even after a metal HG and properly tq'd headstuds, the head will still lift due to cracking or stretching of the aluminum.

Those that wanted truly bulletproof results bought new heads from Toyota, had them x-ray'd for microfissures/cracks and hardness tested before settling for one.

That said, for daily driving and lower power levels, it's fine and I'd even own one for that.

(7M and JZ like reliability should never be in the same sentence unless you're someone like Duane Stevens.)
100% this. There's more to a bulletproof 7M than a new gasket. I had my head hardness tested, crack tested and spectro'd prior to use.

The JZ is far superior to the 7M. The 7M can be great, but factor in a lot of money first. I did three gaskets before doing the extremes.

Happy to answer PM's to keep on topic. The only reason to go 7M these days is nostalgia, so unless you want a 7M (and are prepared to spend lots on the engine) go JZ.

My 7M superiority posts are purely tongue in cheek :p I like it because it's old and suits my old car, but screw building another one.
 
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Prius_F_Sport

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Okay, then. I'll try to find one with a JZ. Thanks for all your advice.
Back on topic, has the person who was going to talk to Tada done it yet?

And on the inside right now I'm just like "Lmao I singlehandedly derailed 15 posts and defined a meme for this forum with one ask".
 

justbake

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Okay, then. I'll try to find one with a JZ. Thanks for all your advice.
Back on topic, has the person who was going to talk to Tada done it yet?

And on the inside right now I'm just like "Lmao I singlehandedly derailed 15 posts and defined a meme for this forum with one ask".
Dont take their comments out of context, youre not building a 600hp 7m
 

Prius_F_Sport

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Are you entirely sure?
Just kidding. I might do that 1.5JZ thing for the fun of it.
 

justbake

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Are you entirely sure?
Just kidding. I might do that 1.5JZ thing for the fun of it.
1.5jz only makes sense if you have a blown 1jz, and want to replace and upgrade the bottom end without changing your entire setup. You could probably piece together a craigslist 1jz head and 2jzge bottom for cheap but will most likely be more expensive piecing the rest together and with more complications than just buying a 2jzgte from the start.
 

Prius_F_Sport

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But what about the higher-compression head? It would make more power, right? I know people put GX160 heads on 212-clone engines because of the higher compression.
 

justbake

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But what about the higher-compression head? It would make more power, right? I know people put GX160 heads on 212-clone engines because of the higher compression.
That is a jdm-drift-boi myth, they have the same compression ratio.
Realistically compression is also determined by your choice of pistons and headgasket so you are flexible no matter which path you use.
 

Prius_F_Sport

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Woops, been spending a little too much time on the small engine forums. My bad.
So there's practically no difference between a 1.5 and a 2?
 

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Woops, been spending a little too much time on the small engine forums. My bad.
So there's practically no difference between a 1.5 and a 2?
The 2jzge and gte heads flows better. But I have yet to see a flow test involving the head and intake manifolds though as the 1jz has short runners and 2jzs have long runners
 

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yeah, basically the 1J head is great for 2.5L and an easy way to increase top end flow (beyond a ported 1J head even) is to install a 2J head (Driftmotion just did this; coined 1.2J). Putting a 1J head on a 2J bottom end is simply to save costs when you already have all the mods/built head and don't want to start over. It's just to save money; that's why the Japanese did it and that's why I was thinking of doing it before sticking to 1J bottom end. The best way to do this is to port the 1J head to flow as close to the 2J head as possible, but given the money aspect many just toss them on and deal with less flow.
 

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