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Thread: how do YOU rev to 9K RPM?????

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    how do YOU rev to 9K RPM?????

    I am asking as many turbo 6g72 people this as I can, and I am quickly running out of ideas. As some of you know, I got my car put back together again with a new crank, rods machined to OEM diameter at torque, and stock bearings. I also have a crank scraper and windage tray. I am also running a Greddy 13 row oil cooler (same design as stock, just bigger), and twin CM 6.5" oil filters. (I am Racer_X from 3si btw. I don't post much, but rest assured, basic questions of "what about your valvetrain?" and "why do you need to rev so high, that's dumb?" are a non issue.). Teh car has DR stage 3 heads with high strength valve springs, upgraided lifters, blah blah blah. valves and heads and stuff are good. Car is running twin 3076 wheels. blows lots of air.......past 5K. That's beside the point.

    long ago.....I was able to rev the car to 9K All motor (long story that will just waste time), but the revving slowly took it's toll on the bearings and as soon as I put power to it (installed the turbos), smashed a rod bearing or two. I firgured it was a machining problem with the rods so I had the rods reconditioned at torque (proper rod bolt stretch), and bought a new crankshaft and set it up as posted above. I was then able to rev the car to 9K without any apparent issues at first. rev to 7 ALL DAY LONG obviously. I don't drive the car much, but I figured the oil pressure was good (tool steel oil pump gears, 20 to 25 psi oil pressure at idle, 90-95 psi oil pressure max), got no signs of knock (banging around) on the knock meter, so it's all good. I must have tacked it all the way up (8500+) about 20 times or so. Well, last night, I decide to iron in my A/F ratio on the top end with the Emanage Ultimate (it works fine. not the issure), so I set the boost controller to wastegagte pressure (12 lbs), and I tack it up to 9000 RPM to verify the fuel map is correct for 7-9K. made a quick adjustment to it, and all seemed to be well. Then I drove down the expressway a bit to let the engine cool (temps were at 95C). when they got down to about 78C, I decided to get the timing sorted as I was taking out 1 degree of timing at 4K and ramping up to 6 degrees at 9. I zeroed it out, and stepped on it a bit, and noticed that just accelerating around 4K resulted in 7 counts of knock (VERY awkward, and tells me things are hitting things that they shouldn't). I say, well, I will reset the logger, and give it a go. as long as it doesn't hit 10counts of knock, I will run it. Well, ran it up to about 8500 or so and it hit 10 counts. I dropped it in neutral, and Oil pressure hit 0 (bright blue light in my face. I immediately pulled off the road and shut it down (as I heard the knocking sounds at the same time). Started it again to verify. Rod knock, Oil pressure SUBSTANTIALLY low (means filters almost 100% clogged (both of them)) and smashed rod bearing(s). I haven't taken it apart yet, but this appears to be 100% RPM induced damage at this point

    I say all that to say this......if YOU are running 9K rpm, or KNOW someone who is (ray, Nelson, IPO, Matt, whoever....) HOW ARE YOU OR THEY DOING IT?!?!?!?!?!?!?!?!?!?!?!?!?!? The only thing I can think of left is to remove my windage tray and crank scraper, but I am doubtfull that will change the end result positively. It looks like >8K + Boost = DEATH. I don't understand or buy this theory, but it's hard to fight the obvious. The crank was balanced with my piston and rod assemblies, the rods were machined to spec, the crank was BRAND NEW, and the bearings were STOCK...........Crank pulley is STOCK. Timing belt is STOCK........HOW DO YOU REV TO 9K WITHOUT SLINGING THINGS APART?!?!?!?!?!?!?!?!?!

    PLEASE HELP ME!!!

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    Feedback Score 1 (100%) Greg E's Avatar
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    Did your oil pump fall apart? Rumor has it they're not up to par anymore.

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    No, the oil pump is still functionally in tact. I have upgraided oil pump rotors installed.

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    Forum User Feedback Score 0 JasonY's Avatar
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    Ray would be the person to ask. I dont think Chris turns that high and Chris is actually the only one still using the 72 crank which may have something to do with your problem since with big power/rpm's it may be getting a little flexible wiping out bearings in the process.

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    Matt (and once Nelson is done w/ his new build) runs all high-rev capable parts (valve springs, dogbox tranny, forged crank, etc). The reason being that the bearing are crapping out on ya is the fact their only only meant to handle a certain RPM, after that they reach the breaking point which in-turn causes failure. You'd have to run ALL forged internals, and pray they hold. How much boost and what kind of turbos would you be running and how often after each race do you have your motor rebuilt?


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    Dirty Dave aka Turbo Tension was revving to 9k RPMs and ended up rebuilding his new OEM shortblock after not many miles. The bearings were toast and I don't think he really knew what caused it. Like you he had Stage 3 heads and everything was properly built.
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    Quote Originally Posted by skater334 View Post
    Matt (and once Nelson is done w/ his new build) runs all high-rev capable parts (valve springs, dogbox tranny, forged crank, etc). The reason being that the bearing are crapping out on ya is the fact their only only meant to handle a certain RPM, after that they reach the breaking point which in-turn causes failure. You'd have to run ALL forged internals, and pray they hold. How much boost and what kind of turbos would you be running and how often after each race do you have your motor rebuilt?
    Wow that was technical.

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    Always thought it was due to our cranks oil passage routes?

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    Quote Originally Posted by skater334 View Post
    Matt (and once Nelson is done w/ his new build) runs all high-rev capable parts (valve springs, dogbox tranny, forged crank, etc). The reason being that the bearing are crapping out on ya is the fact their only only meant to handle a certain RPM, after that they reach the breaking point which in-turn causes failure. You'd have to run ALL forged internals, and pray they hold. How much boost and what kind of turbos would you be running and how often after each race do you have your motor rebuilt?
    Hmmm.. thank you for your responce, however i would probably humbly disagree that bearing life is primarily dependant on rpm. There are a LOT of factors involved. I think i finally understand why high rpm is leading to continued failure. One hint is i think Nelson will be one of the few people to overcome this restriction.

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    Quote Originally Posted by Armond30 View Post
    Hmmm.. thank you for your responce, however i would probably humbly disagree that bearing life is primarily dependant on rpm. There are a LOT of factors involved. I think i finally understand why high rpm is leading to continued failure. One hint is i think Nelson will be one of the few people to overcome this restriction.
    Matt has too, he offered to sell me his block from the Stealth and said they when they rebuilt it the bearings were just as good as ever and they beat the piss out of it.

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