What would you run 7m or 6m?

[NashMan]

well i have 6m in my race block right now and thinki plan to keep it since it's a shit load lighter can care less about the vib


now this is kicker the 7m crank will be smoother and the engine will just last longer then the 6m but for how much longer ?


all what whould you choose and why

 

[NewWestSupras]

If it's balanced I can't see it being that much different. I like my 6M just fine. These are pretty smooth power plants no matter which crank, imho, Ryan. At 500 hp, there's not much time to think about anything except the next gear anyways, sí ?!

 

[turbodriz]

bump on this thread. Have the same question and maybe some of u guys with more experience can chime in. Yes the 6m in lighter but you can lighten the 7m and have more balance from the extra counter weight maybe???:1zhelp:

 

[Kai]

I'd go for the fully counterbalanced 7M. Shot peen the crank, knife edge it and be done with it

 

[mkIIIman089]

6M.

 

[Slow66]

I'm a 6m guy ....

 

[turbodriz]

6M.

slow 66 that is cool but why are u a 6m guy and not a 7m. Do you feel the extra counter weight doesn't mean shit?

 

[Tanya]

Russ M ran over 700+Hp with a 6MGTE, don't see why that crank can't handle what you'll throw at it Nash...

 

[NashMan]

well that is time will tell answer

but i thinks i going to keep my 6m just casue it all ready in my race block


plus the rev limt got lowered in 89 caus eof the 7m crank

 

[Tun_x]

less is more when it comes to rotating mass.... at least in most cases

 

[Sawbladz]

If I had access to both I would run the 7M. I am not a big fan of revving really high and I want as smooth an engine as possible. I would also run the newer style block.

 

[mc_h]

If I had access to both I would run the 7M. I am not a big fan of revving really high and I want as smooth an engine as possible. I would also run the newer style block.

Keep in mind...You WANT to rev higher with a big turbo.

 

[empera]

very interesting thread, subscribed.

 

[MK3.0dudeman]

well the 86.5-88 7M blocks came with a 6M cranks and I would say at redline there not as smooth as the 89+ 7Ms.

I would say screw it and go with the 6M.I say it could make just as much power as a 7M just look for it's weak points and make em stronger.

I'm more a 7M guy over a 6M but when it comes down to it the 1J's more my type of motor and if you just want a almost bomb proof motor for power go with the 2J.But it's people who go with the under dog motor and kick the kings ass that gets props in my book.

 

[Sawbladz]

Keep in mind...You WANT to rev higher with a big turbo.

Keep in mind that I will choose my turbo to have the power band where I want it to be. None of this spooling at 5000 BS for me.

 

[IJ.]

Have ran both cranks in the same motor 2 weeks apart with the cranks being the only change.

6m: accelerates quicker but harsher from idle to 1500 rpm under redline (8300) smoothed out for the last 1500.

I had my limiter set for 8000 and it would overshoot by 300 rpm.

7M: slower initial to spin up but was noticably smoother at all rpm, same 8000 limit it would catch it by 8050 rpm.

My "solution" was to lighten a 7M by around 6Lbs and get the best of both worlds, could have gone lighter but it would effect the inherent balance of the crank.

6m


7M


Lightened 7M

 

[turbodriz]

Thanks guys gor your input.

 

[topguncam3888]

My "solution" was to lighten a 7M by around 6Lbs and get the best of both worlds, could have gone lighter but it would effect the inherent balance of the crank.

If I may ask how much did lightening the 7M cost you?

 

[topguncam3888]

or if you did it yourself how much work was it?

 

[IJ.]

Top: It was done at a crank shop sorry I can't remember how much it was (not cheap from memory)

They did most of it on a CNC Mill to keep it consistant.