Safe Rev Limit

boosted88 · Post by **boosted88** » Wed Jun 07, 2006 10:06 pm

What do you guys regard a safe rev limit on a 4G63?Engine fully balanced with balance shafts reoved and steel rods with Wiseco pistons.

Is the stock cam a limiting factor?

Running 3D engine management on ignition and fuel, more worried about some thing breaking up in the bottom end! :?

Cheers Paul.

Starion VR4 · Post by **Starion VR4** » Thu Jun 08, 2006 5:39 am

yea the cam is a limiting factor, engine will REV to 8000RPM safely but not produce usable power, the STD Cam is good to about 5500RPM, depending on what inlet manifold U have. :beer

filiboy · Post by **filiboy** » Thu Jun 08, 2006 3:40 pm

Starion VR4 wrote:yea the cam is a limiting factor, engine will REV to 8000RPM safely but not produce usable power, the STD Cam is good to about 5500RPM, depending on what inlet manifold U have. :beer

so u have to buy some aftermarket cam ? or is cheaper to buy VR4 head and install it :roll:

crshbndct · Post by **crshbndct** » Thu Jun 08, 2006 3:44 pm

what is the limit for a vr-4 headed 4g64, with standard crank + vr-4 rods(both of which i believe are forged anyway), and forged slugs

toysrus · Post by **toysrus** » Thu Jun 08, 2006 4:15 pm

Yeah, it depends what Inlet Manifold you have running the factory Camshaft :D

http://www.fr33z3.net/starions/Apr06/dsc000650ec.jpg

http://www.fr33z3.net/starions/Apr06/dsc000667ob.jpg

For reliabilty, though, the lower the rpm the better, make your rev limit 500-1000rpm after max power, once you've had it tuned on the dyno

boosted88 · Post by **boosted88** » Thu Jun 08, 2006 4:25 pm

I'm running a L300 manifold, I was thinking of around 6500 so that sort of stacks up, is there anything to be gained on dialing the cam in better than standard, I'll just remove the dowel and lock the bolt up tight when its adjusted, just like most Fords over here do! :)

Paul.

BTW I'm still looking for some ECumap data can't anyone give me a dump from a 3D map??

Post by **Alspos** » Thu Jun 08, 2006 4:53 pm

Buy a cam wheel and do it properly. Bolt slips slightly and it's game over.

Starion VR4 · Post by **Starion VR4** » Thu Jun 08, 2006 4:58 pm

Paul, retarding the cam 4-8deg will help top end performance, but U will loose some bottom end, If U can get hold of the 2.4L SOHC cam in solid grind use that, 6500RPM with that manifold would be a last resort, when i ran that manifold & setup on my 2L, useable power was finishes at 5600-5800RPM.
But i didn't change the cam timing. If U retard it 4-8 DEG U could see some improvement say to 6200RPM. :beer

davidbek95 · Post by **davidbek95** » Thu Jun 08, 2006 8:47 pm

500 rpms before it blows up that wat i reckon is about rite rofl

boosted88 · Post by **boosted88** » Thu Jun 08, 2006 9:55 pm

Both the Cams in my Focus ST 170 are held in place with just bolts, I just clean the threads and use plenty of Loctite, adjustable cam wheels just allow you to put the cam back where you came from easier! Why waste the money?

Mine you forget to torque it up and your right it's game over :D

Cheers Paul.

flav · Post by **flav** » Fri Jun 09, 2006 1:34 am

7000 is safe.

OLD FART · Post by **OLD FART** » Fri Jun 09, 2006 5:07 am

I have the HALTEC set to cut rpm max at 7200 .At present my cam is a Rallyart grind and has power all the way to 7000.

rallidave · Post by **rallidave** » Sat Jun 10, 2006 9:50 pm

crshbndct wrote:what is the limit for a vr-4 headed 4g64, with standard crank + vr-4 rods(both of which i believe are forged anyway), and forged slugs

factory forged vr4 rods??? is this true?

flav · Post by **flav** » Sat Jun 10, 2006 10:22 pm

Hey u old fart (young punk hoon). U have specs on that cam? Whats it like down low?

OLD FART · Post by **OLD FART** » Sun Jun 11, 2006 6:35 am

35-70 70-35 with 305 lift at lobe .Powerpulls from 3800.Turbo has 1.902 6blade compressor wheel BMW M3CSL with computer chip could not catch me down back straight at Q raceway .Havent stopped smiling yet :D :D

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Safe Rev Limit

Safe Rev Limit

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