Discussion on the potential of the 7MGE

toy fanatic78

addicted to toy's
Oct 17, 2008
689
0
0
Elkhart,IN
Jervis Mcstabby;1221045 said:
Supposedly Cartech got 330hp out of the GE, but I can't find much details on it

Absolute speed was saying the guy that built his motor was supposedly building a 400hp na 7M for a 4-runner,I wonder how far he got on that idea.
 

dexterrogers

Slow worker
Jul 25, 2006
15
0
0
Calgary, AB
well here's some food for thought > Paeco offers an "ultimate" 7MGE making over 400hp NA. It's not cheap, but from the parts lists I see there are some very fancy parts in there. If nothing else the paeco motor shows such power levels are plausible, at least.

TOYOTA SUPRA 7-MGE $11200 (412)HP
http://paeco.com/Engine%20Price Two.htm

On compression ratio and stroke > 12:1 lightweight pistons are on my list. I'm still liking the stock stroke, plus with the overbore the ratio goes to 85bore 91stroke, closer to a square motor, so I would think a step in the right direction for rev-ability.

I find the hardest thing to explain to people is why I'm building such a motor. I've actually owned many supras. While I like the power of the MkIII turbo, and ease (by comparison) of modification, I found the body was not suited to the roads I aim to conquer. I enjoy the handling characteristics of the MkII, more suited to tight compound corners and winding lake roads. Also more suited to such roads is a nice high revving natural aspirated motor. More than anything thought I like the simplicity of carbs, the hand tune-ability yada yada yada I have to run
 

gaboonviper85

Supramania Contributor
Jan 13, 2008
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Northeast Philly
benchwarmer;1218886 said:
The big reason why so many people doubt the GE is that so few people have actually tried to make power with it and most of those who have didn't achieve much. Bolt on mods on the 7M give a negligible power gain. The motor was really designed with a turbo in mind so to gain any real power internals need to be changed and the head worked over. Since that requires a rebuild and substantial money, it's easier and cheaper to just go turbo and be happy.

While I truly respect the members of this board and there is an unbelievable wealth of knowledge here, very few of the members have any experience building NAs. Take the advice you get on this topic with a grain of salt as most of it is going to be conjecture. For myself, I love the sound and the drive of an all motor car so I wish you the best.

Dangers of high piston speed as explained by SupraCentral: http://www.supramania.com/forums/showpost.php?p=180719&postcount=18

not true...not true at all....many people have tried to make power on a 7mge but the head doesnt flow well enough to get high power...yes im a mk2 it will be wicked but still slow in terms of whats considered slow on this forum.

the 7m is a motor that needs some sort of forced induction such as nitrous, turbo, supercharger,etc....its a great motor that can handle massive amounts of power but isnt a good design to make power on its own.
 

dexterrogers

Slow worker
Jul 25, 2006
15
0
0
Calgary, AB
http://paeco.com/Engine%20Stages.htm
http://paeco.com/Ultimate Engine.htm

Like I said, I have a hard time convincing people why I chose this set up. While turbo 500hp is great and all, what is the point? To go fast in a quarter mile, or race cars on the freeway? This isn't the purpose of this car. In my turbo supra I've gone very fast, and had fun with the top off cruising mountain roads tunes blastin. What I'm aiming for is a very communicative, linear, strong but ultimately simple car. I work in the car bizz and have had the pleasure of many many vehicles. New cars I find very unappealing. There is the initial fun factor but a 425hp SRT8 gets boring WAY too fast. I think the automatic is to blame. All of these turbo and supercharged FWD cars impress me with their ability to spin the wheels but the handling is somewhat lacking. I'm not sure why but everyone seems to be obsessed with high power output, really though when do you utilize that power? Or how often better yet? For what I am trying to accomplish and the intended use of this car I believe it will be a capable machine. Not everyone who owns a supra is aiming to embarrass lambos or rocket down the quarter mile or flex their dyno dink. My car is being built to drive, with maximum driver control.

Porting and oversized valves/de-shrouding should help with the head flow, but I think much of the restriction comes from the intake, which really takes a substantial modification to optimize.
 

gofastgeorge

Banned
Jan 24, 2008
944
0
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Texas
From what dealings I have had with Paeco,
they are 95% smoke & mirrors.
That guy lives off the SCCA wana-bees
(the doctor lawyer type),
that never turn a wrench themselves.

The few times I talked with him, all he did was blow BS my way,
and never backed anything up with fact, or hard numbers.

I don't think a 7MGE, with it's rod length/stroke ratio,
that limits it's max RPM to about the 8500 range,
could go into the 400 HP range.

Maybe with shorter stroke and/or longer rods,
so that it could rev up into the typical 4-valve race engine range of
12,000-14,000 like the 4AG guys do.
 

wiseco7mgt

dirty mechanic
Aug 12, 2007
811
0
0
queensland
The guy wants a 7mge that goes hard. Why not just help him out with tips instead of telling him to go turbo? I used to own a mark 2 and i understand what you're talking about handling wise, they are amazing little cars on the very tight stuff and you can switch to dirt and still have great control.
I personally wouldn't have gone carby over fuel injection but it's certainly different and will sound great when you put the foot down.Even if you can get the motor to produce roughly 200 -240 rwhp it will feel fast and perform quite well assuming your a decent driver, and if racing it is your game then strip it to the shell and get another 200 odd kg's off it, it can be done.
It's always a cheaper option than spending big bucks on a motor.
I met a older guy here in australia that owns a genuine ex bathurst mark 2 that has roughly 300 whp and uses a 5mge block, the engine only lasts a few races unfortunately and he wont tell any secrets.
 

Moy

It's broken...
Aug 6, 2008
2,432
0
36
Beach Park, IL
I've been looking at Paeco's site, and it looks like a scam. Honestly, a freshman in high school who's taken a basic computer class can make a web page with a gray bg, red font, and have pictures that look like someone used photoshop to create them.
(Sorry to the OP for going off-topic in their thread)
 

wiseco7mgt

dirty mechanic
Aug 12, 2007
811
0
0
queensland
benchwarmer;1224743 said:
I'd kill a hobo's mother to know how he pulled that off.

Just searched some old info and he was putting out around 300 hp (at the crank, sorry)He mentioned it was extensively modified .It was the old williamson entry that was also used by mark skaife.
 

Tire Shredder

New Member
Sep 15, 2005
569
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Oshawa
benchwarmer;1224743 said:
I'd kill a hobo's mother to know how he pulled that off.

This is the car:
p1224921_1.jpg


It won the British Open Rally Championship Group ‘A’ category 1985.

this is a post hinting at the engine work. he doesn't give full disclosure but it sounds like it has had some extensive prep work.
http://forums.celicasupra.com/showpost.php?p=332190&postcount=12

and this is a thread about it:
http://forums.celicasupra.com/showthread.php?t=18945&highlight=Supra+BTCC

more pictures here:
http://forums.celicasupra.com/showthread.php?t=28616

although vague, the power level must have been considerably high to compete with the rest of the field. Hell, it actually beat them.

benchwarmer;1218889 said:
MKIIs are lighter. I stripped down MKII with a high power 7M should be a blast to drive.
yup, it is. A 7MGE that wasn't assembled by a monkey in a mk2 is a lot of fun.
Build: http://www.supramania.com/forums/showthread.php?t=45761&highlight=Tire+Shredder%27s

Video: http://www.youtube.com/watch?v=_WK4GddPLRM

Nearly all the posts in this thread are correct except this one:
empera;1218883 said:
its a waste of money, maybe if u swapped the GE into something lighter.

Whether something is a waste of money or not is a subjective question..

Firstly, it helps that this engine is in a mk2, it really does. Secondly, it all depends on his goals whether it is a horrible idea or not. I'd suspect without doing some very wild modifications (not running on something ridiculous like methanol, huge stroke, bore, and usper high rpm etc.) 250whp would be the peak of the motor. I say this because there's a 6mge in Denmark that has home made ITBs, a tec standalone and cams producing 217 whp. A little more fine tuning may increase this a bit. I'd imagine the addition of a 7mge couldn't produce much more power than a properly prepared 6mge...

video here: http://videos.streetfire.net/video/My-6mge-with-homemade-itb_128571.htm

The reason bolt-ons don't do much to the 7mge is that it's a fairly well engineered package to begin with. Everything works together and there is no blatant bottleneck. For more performance, almost everything must be changed. You've got to understand the M series block was first installed in a car in 1965. which means it was designed in the early 1960s....with information gathered from the 50s. The engine (block) was in service for 27 years and the 7m was the last development of the motor. it was the best they could do with it...The block height and deck width were all originally set out that 27 years ago, when head design wasn't as thoroughly understood and the benefits of multi-valve heads weren't either. when the 7m head was designed by yamaha they were restricted by the deck width, overall height, and piston bore size. all of which limited the size of the valves and ports. Needless to say when you look a high performance head of more recent years (say, a gsxr 600 street bike) or a honda K20 there is a big difference to our 7m head. to achieve bigger, modern car numbers, it truly does need boost to compensate for those head restrictions.

as for absolute max power, defiant 7m is trying to test the limits here:
http://www.supramania.com/forums/showthread.php?t=62953 I think it's relatively safe to say he's trying to get the most out of the engine and he hopes for 450hp. Now this is just theory as he's not done yet. and it should be noted that even the 250whp number I threw out there is just a guess as it hasn't been seen yet...or at least, by the online community.

Like I said it depends on your goals and what will make you happy. Do you want to do something that hasn't been done frequently and enough money to make it a reality? go for it! As long as you understand the car will never be a rocket ship. The issue with the 7MGE, and any motor for that matter is that there becomes a point were expenditures are exponentially increased compared to the performance gained. How far do you want to take it? This indeed does happen for turbo motors as well, but happens at a higher power level. Ultimately it's his decision if it's a waste or not. not only may his decision be based one power but also more subjective things such as response, power delivery, uniqueness and even sound.

I for one, wanted to find the sweet spot for the 7mge. I knew I would have boost someday so it did not make much sense to spend huge amounts of money. I wanted to do things that mattered to increase power where it needed it and not throw my money away, when I could have been saving for boost. What I do have now is a car that is fun to drive, reliable, inexpensive, has a good idle and is a blast to drive at local autocross events. I had a realistic goal (somewhere around 180whp) without a lot of money and think Iachieved it. I am happy. So long as your goal is also reasonable, and you understand the caveats you will be happy too.
 
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wiseco7mgt

dirty mechanic
Aug 12, 2007
811
0
0
queensland
The British open rally and the Australian Bathurst are two very different events.
Here's a pic of the car.
sm_photo_missing.jpg

From memory the guys a regular on toymods and his sig is "art racing", he bought parts off me when i was wrecking a ma61 and he told me some of it's goodies that blew me away.
 

wiseco7mgt

dirty mechanic
Aug 12, 2007
811
0
0
queensland
My apologies tyre shredder, i didn't realise he competed overseas with a different colour scheme.
Yes that's the same guy his name from memory is "john".Hmmmm i still have his number.