7A block/bottom end. Relative vs abolute strength. Options

[Jehuty]

I'm interested in the 7AGE setup, and there is some good info out there, but it's vague in some spots...

Specifically, about strength of the block and bottom end of the 7AFE. Most refferences to the strength of these parts is stated relative to the 4AGE. For example, the fact that the 7A block has less ribs than the 4A, or that the flywheel bolts up with less studs. Yeah, great. It's not as good as the 4A, but what does that mean? I want to know what the actual rev and boost limits are.

Reason is that altho the (7A) block, crank, rods and pistons are all stated as being weaker than the 4A counterparts, the only parts that looks really "weak" (in absolute terms) to me are the pistons. The rest looks like a pretty stout little engine. Am I correct?

So if anyone knows where I can find some info about the rev and boost limits of the 7A (or the 4A for that matter!) please help me out! First hand experience from anyone who's blown a few would be nice too. Heck, I'd even appreciate a little heresay. ;)

[Jehuty]

Yeah, I found myself at odds with Toysport's advice. Reminded me of Mazdatrix back in the day... "No that's not feasable. Leave your car alone."

Anyhow, thank you thank you thank you for all the advice. I tried the search and I didn't quite find what I was looking for. I did, however find the conversation between yourself and Froutou when he was considering is head swap.

He was plannig to use an emanage and you recommended against it. However Im still not quite clear on why. The emanage will allow use and tuning of a map sensor on the 4a head, correct? Or is the 7A ecu too limited? Maybe I should go find that thread and read it again....

One more question... you mentioned "reworking" stock rods. Are you reffering to a standard strengthening process, like shot peening?

Thanks again for taking the time with your replay. The reason I'm not entertaining the idea of a straight swap is that I hope to one day have my own firsthand knowledge like that. I want to build and tune an engine myself. I'm tired of paying other people to do this sort of stuff. I understand the principles anyhow, I just need to DO it. I figured building a 7AGE hybrid on a stand over time would be a good place to start, since it's about the epitomy of a standard hi-po dohc. Not too pricey either. =)

[Kwanza26]

Yeah, I found myself at odds with Toysport's advice. Reminded me of Mazdatrix back in the day... "No that's not feasable. Leave your car alone."

Yeah... they're just guessing about the 7A...

Anyhow, thank you thank you thank you for all the advice. I tried the search and I didn't quite find what I was looking for. I did, however find the conversation between yourself and Froutou when he was considering is head swap.

He was plannig to use an emanage and you recommended against it. However Im still not quite clear on why. The emanage will allow use and tuning of a map sensor on the 4a head, correct? Or is the 7A ecu too limited? Maybe I should go find that thread and read it again....

I was actually warning him against using the AE86 harness in general, as he did. I was trying to tell him even with eManage, he won't be able to tune his car, and that's what happened... The donor harness he used was the AE86 Corolla GTS harness, which is AFM based. It's one of those odd ones that don't read out voltage in the "piggyback range" or a range where piggybacks can intercept. It's all said and done now... no use going over it again.

One more question... you mentioned "reworking" stock rods. Are you reffering to a standard strengthening process, like shot peening?

Yes... production casting creates weak spots in the rods and cleaning up those spots will essentially strengthen them. A google search can probably explain it better than I can.

Thanks again for taking the time with your replay. The reason I'm not entertaining the idea of a straight swap is that I hope to one day have my own firsthand knowledge like that. I want to build and tune an engine myself. I'm tired of paying other people to do this sort of stuff. I understand the principles anyhow, I just need to DO it. I figured building a 7AGE hybrid on a stand over time would be a good place to start, since it's about the epitomy of a standard hi-po dohc. Not too pricey either. =)
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No problem... good luck. If it's a well placed question with decent research done... I have no problem with going into detail... ;]