Rb30Det Block Building Concerns

[j2fast]

so i have my internals at the machine shop an i was giving the option like 5 times to knife edge my crank, and i said no 5 times, but know im kinda of thinking bout it b/c of the fact this is an all-out motor, but its gonna be daily driver. im getting the crankshaft raced balanced to 11k rpms, i have spool rods, mahle pistons(8.5:1) rb26 head BC valve train with 280 cams. my goal is 700-800 whp( dyno queen #'s) but for everyday like 600 hp. im using e85 with t72 turbo.

The real question is, is knife edging the crank bad on daily driven cars? what is the down side of it? im not worried bout the cost of it, will it drive alot different the reg crank?

[KiwiRS4T]

If you want big power you need to balance the crankshaft (and other components) and get a quality harmonic balancer. How can that do any harm??? Why would it drive any differently at moderate speeds/power levels?

[*LOACH*]

so i have my internals at the machine shop an i was giving the option like 5 times to knife edge my crank, and i said no 5 times, but know im kinda of thinking bout it b/c of the fact this is an all-out motor, but its gonna be daily driver. im getting the crankshaft raced balanced to 11k rpms, i have spool rods, mahle pistons(8.5:1) rb26 head BC valve train with 280 cams. my goal is 700-800 whp( dyno queen #'s) but for everyday like 600 hp. im using e85 with t72 turbo.

The real question is, is knife edging the crank bad on daily driven cars? what is the down side of it? im not worried bout the cost of it, will it drive alot different the reg crank?

I haven't done this but from what I understand knife edging the crank feels like having a lighter flywheel - IE it will build up revs quicker but also lose them quicker too (which is usually a bit of a negative for a daily). Also there is less parasitic drag when the crank moves through the air/oil so you might gain a bit of power too.At the end of the day its really going to be a subjective thing whether you want it done to your car or not as no one but you will know if it feels OK as a daily. Sorry not too helpful.

Edited March 27, 2011 by *LOACH*

[j2fast]

If you want big power you need to balance the crankshaft (and other components) and get a quality harmonic balancer. How can that do any harm??? Why would it drive any differently at moderate speeds/power levels?

i am actually doing the balancing of crankshaft, rods, and pistons. but have crankshaft balanced to handle 10k of rpms aswell

[j2fast]

I haven't done this but from what I understand knife edging the crank feels like having a lighter flywheel - IE it will build up revs quicker but also lose them quicker too (which is usually a bit of a negative for a daily). Also there is less parasitic drag when the crank moves through the air/oil so you might gain a bit of power too.At the end of the day its really going to be a subjective thing whether you want it done to your car or not as no one but you will know if it feels OK as a daily. Sorry not too helpful.

what do you mean by lose revs quickly??? i was thinking bout just going with it but didnt know if the car would drive different from a standard crankshaft

[The Dan]

The money would be better spent on a forged crankshaft that will ACTUALLY rev to 11k rpm. Your engineer can only balance it to 0 anyway, your steel crankshaft is not going to survive very long after 8500rpm.

Not only do you risk destroying the crankshaft due to the very aggressive nature of the machine that cuts it, but the benefit of having a knife edged crank is minimal, like have a lightened flywheel. The cost far outweighs the benefit IMO.

[j2fast]

The money would be better spent on a forged crankshaft that will ACTUALLY rev to 11k rpm. Your engineer can only balance it to 0 anyway, your steel crankshaft is not going to survive very long after 8500rpm.

Not only do you risk destroying the crankshaft due to the very aggressive nature of the machine that cuts it, but the benefit of having a knife edged crank is minimal, like have a lightened flywheel. The cost far outweighs the benefit IMO.

ooohh thanks for the tip. i was planning on using it till about 8-8500 actually that u said that. well if its not that much of a gainer than i may just skip that. what about micro polishing??

[BMYHOE]

Dry sump i hope

[*LOACH*]

what do you mean by lose revs quickly??? i was thinking bout just going with it but didnt know if the car would drive different from a standard crankshaft

The drivetrain will have less inertia therefore when you take off from a standing start or change gears you will have to be more delicate with throttle control in order to keep the revs up otherwise it will stall. Could be a hassle if you drive in traffic a lot. Listen to F1 cars (which have no flywheels and low rotating masses) as soon the throttle is closed the revs drop - much quicker than a street car. Its just a different driving experience which you may or may not like. I know its probably difficult but the best way to get the experience is drive someones car who has a light flywheel.

[j2fast]

has anyone used 280 cams in rb26 head? what size turbo and is it worth the head replacement parts( valves, springs, retainers) i also have 1mm oversize valves. should this flow pretty good??? im thinking bout porting the head out myself but havent decided on it yet what do you think???

[bubba]

My mate has 280s in his 30DET with a T04Z. IMO they are too big, it has none of the low down 30 torque. Boy does it scream to 8500rpm and want to keep going though.

[j2fast]

My mate has 280s in his 30DET with a T04Z. IMO they are too big, it has none of the low down 30 torque. Boy does it scream to 8500rpm and want to keep going though.

does it make nice power and on what type of psi?? since i have these should i get a bigger turbo??? im thinking bout goin with s372 borg warner.

[N1GTR]

[j2fast]

does anyone know the real diff between race bearings and standred bearing? i bought the ACL race ones but i guess now im thinking bout it and dont really know the differeance.