What to Rev to?

[TheDarkRaver]

Hey all,

Ok not long now until the mighty 7M is back on the road (after 3 years of sitting in the garage waiting on me!!)

Now I remember seeing a thread a while back about what is a safeish :icon_evil Redline. So my question to any that might know is what should I set the rev cut to when I get the car tuned very soon.

The motor has been totally rebuilt, full balanced bottom end (6M crank), forged pistons, O-ringed block, copper headgasket, full head reco with 55lb valve springs (35lb are what is std). A Garret GT35R hanging of the side 660cc injectors and a Wolf3D to run the lot..

Now I am looking for the 350rwkws mark (which should be fairly achievable with my setup)

Ok so my question I was thinking 7000-7500rpm should be fairly safe, yes/no and why?

 

[IJ.]

What brand valve springs?

 

[starscream5000]

Aren't the chevy replacement mod inner springs around that mark?

 

[mhopemk3]

Get a dyno run and rev it to the max HP range of the Dyno. Why go beyond that? Although, I am sure it will sound sweet as all get out!

 

[bigaaron]

My 7m has no problem reving to 7250 with a completely stock head and a similar sized turbo.

 

[TheDarkRaver]

Not sure on brand as the machine shop orded them in for me, all I know is they are good for 10mm lift and are 55lb springs.

Yeh 7250 is about what I was thinking as the turbo shouldnt be running out of puff by that mark..

The only thing on my weak list are the STD rods what sort of power figures have people made with them?

Marc,

 

[mkIIIman089]

Get a dyno run and rev it to the max HP range of the Dyno. Why go beyond that? Although, I am sure it will sound sweet as all get out!

So when you shift its still in a good power band.

 

[IJ.]

55 sounds light mine are 78's but I broke one spinning it to 8000 and holding it there for a minute or so!

 

[mhopemk3]

So when you shift its still in a good power band.

I only drop about 500rpm's. I may be wrong but if your max hp/tq is around 5800 why would want to rev to 7K? I don't rev that high so If there is a reason please share!

I could see revving that high if the powerband is up around 7k. Maybe I am just dreaming of how sweet that would be..

 

[JoeC]

I usually end up shifting at 6k through all the gears.

 

[starscream5000]

I would start out with setting the rev limit closer to stock and get a good feel of your powerband there. If if looks like it will be making more power after that mark, then start bumping it up some .

 

[LordLo]

I'd say just set it to 6,500 on the stock head since it seems to run out of power after that anyway.

 

[2543arvin]

im reading everyones posts....is there no way to accurately know what is the ideal rpm to shift at, or is it just trial and error?

 

[bigaaron]

Put it on the dyno and find out :icon_wink
When it stops making power there is no reason to go much higher in rpm.

 

[IJ.]

Mk3hope has it right, I'll usually spin a motor a set amount higher so the next gear lands in the meat of the torque curve! (around 500>800 rpm more than max torque)

But it's fun spinning it to 8000+ as 7M's sound awesome up there!

 

[Idealsupra]

Put it on the dyno and find out :icon_wink
When it stops making power there is no reason to go much higher in rpm.

unless it holds that power steady

but yeah find out on the dyno where max hp is..... and shift around there.... however if you have a good cam setup and the power plateus then run it out

 

[bigaaron]

I agree, I said "not much higher" :biglaugh: