7mge - whats its limits and how do you get there

[driftae71]

just wondering if anyone had followed the path of blown headgasket goodnes and built a 7mge to higher than standard specs... and if so how did u get there...

[CrUZida]

If you are asking whats the best/proper way to fix the BHG, then deck the block, skim the head (make sure the head is not corroded), MHG, ARP studs torqued to 80ft-lbs.

If you are asking what should you do to make the 7M better, then the answer is put a different motor in there (JZ, UZ etc)

[amichie]

I have Brian Crower stage 2 cams, bored out to 84mm, ARP studs, Supra ACIS intake, cat back system, and a few tweaks in the ecu and it is now a reasonably pokey motor. No match for a 1jz conversion that would have cost about the same and had a lot more potential.

I am still forever watching the temp gauge even after having the block decked and head shaved.

[indeecent]

25deg of ignition timing and its still holding, + bouncing off the limiter for about a year now

sounds about its limit

Amichie has done it the more sensible way, and obviously puts down more power then most the GE's around, but its still nothing on anything with FI, and when you factor in you can do a NA-T fairly cheap, its almost silly not to... unless you want that NA sound, and to be different

[RyleyMA61]

Ed-jza80 built a tough 7mge... rona owns it now and is for sale....

but as already said, there are better bang for your buck options- even the 7mgte is getting cheap now (but old and shit too)

[amichie]

25deg of ignition timing and its still holding, + bouncing off the limiter for about a year now

sounds about its limit

Amichie has done it the more sensible way, and obviously puts down more power then most the GE's around, but its still nothing on anything with FI, and when you factor in you can do a NA-T fairly cheap, its almost silly not to... unless you want that NA sound, and to be different

I've recently tried the ecu crystal mod to up the rev limit. Seems to work if your interested.

What rpm do you get fuel cut at??

[indeecent]

I've recently tried the ecu crystal mod to up the rev limit. Seems to work if your interested.

What rpm do you get fuel cut at??

Just over 6500 i think, dont pay too much attention to it, but its around there

I haven't heard much on the crystal mod, a basic rundown if you can would be good, but my question is, how much will a stock 7m take in the way of revs

[amichie]

Just over 6500 i think, dont pay too much attention to it, but its around there

I haven't heard much on the crystal mod, a basic rundown if you can would be good, but my question is, how much will a stock 7m take in the way of revs

I dont know when the stock bottom end will let go. Mine is an auto and so never gets near the rev limit. However with the BC cams it still has good power when the ecu changes up the gear.So anyway I was reading on supramania about changing the crystal frequency in the ecu to change the rev limit. I tried it out of curiousity to see if it also increases the gear shift points and it seems it does. So now I am a happy boy.

The stock crystal was 4.19Mhz and Jaycar had a 4.4 in stock so now the shift points have been upped by about 5%. I will order a 4.6 Mhz crystal off RS or Farnell and give that a try, It will hopefully up the shift points by 10%.

[indeecent]

So does that mean the 4.6 Mhz slows the ecu down? how does that change fuel delivery? and if we did this on a GTE ecu, timing curve? {one going in an mx63 wagon}
I would imagine moving the AFM a bit towards the richer side {though at WOT really doesnt change anything} would be required to compensate for the differences, at least at higher RPM.

My car is auto also. when I'm giving the car some I've always got it in L or 2, i need to have some grasp on where my revs stop before i change haha...

I might look into it, that redline does shit me, though its there for a reason

[amichie]

No idea what the crystal freq change does to fuel delivery. I imagine it would make it slightly leaner at WOT.

It also seems to have given me a little bit more ignition advance.

My guess as to how it works is the ecu is counting clock pulses to determine rpm, car speed, injector pulse width etc and the faster crystal the shorter the injector pulses would be.

BTW I thought you had joined the manual conversion brigade.

[indeecent]

thats in the near future, with the engine swap {no point fussing about twice is there}, ive been fairly hard pressed in money situation at the moment, otherwise it would be done, paying off the eurotrip haha...

i'll look at doing this, just for fun, or to kill a motor when its time to pull everything apart

[The Real Roadrunner]

If you are asking what should you do to make the 7M better, then the answer is put a different motor in there (JZ, UZ etc)

you speaketh teh truth, IMHO a 7M is only worth its weight in scrap metal (cast iron aint worth much) and isn't the best base for a "performance engine", save your pennies and do a jz or similar

cheers
linden

[RObErT_RaTh]

Get in contact with 'ed_jza80' and '7MA61' because ed built up a pretty mean 7MGE and 7MA61 now owns the car (even though it's currently up for sale)

http://toymods.net/forums/showthread.php?t=27207

If you want a decent performing NA motor then get a 2JZGE and stick that in instead. Newer engine, not plagued with headgasket issue, will be better in the long run. If you can't afford a new engine and just want to improve the old one, don't. You'd be putting in a lot of time and money for less than reasonable gains. If you need a working car just get the HG fixed and save your pennies for a bigger and better engine.

I've been through it all, considered every option for more power or a conversion and in the end I settled on a 7MGTE. Good bang for buck

[RONA]

2jzge are slow though just ask wayne

7m's are good when they work but availability of parts and fresh engine the 2jzge is a much better alternative.

[RObErT_RaTh]

2jzge are slow though just ask wayne

Isn't wayne's making 140+ rwkw? Think it'd do alright

EDIT: 148rwkw actually