The search function is your friend. Use it and spend hours reading old threads. The data is out there.

Darlen is no longer with MAM. :shakes head:

I have my redline set at 8,000. My shift light at 7,500. I shift at 7,500. The only time I hit 8,000 is at the end of the straight to save an up shift, down shift condition.

You're presuming no search was done. Search "broken crankshaft" and you get six returns, none about breaking a crank. One from 2016 where a guy directly asks about the limits of breaking the crankshaft and the one reply he gets is more focused on HP and a slight guess at RPMs. Try "broken crank" and you get about two pages, but only one useful thread (in regards to the question), sans this thread that now shows up in that inquiry. And that one thread doesn't actually state why, how, conditions, or anything of the like; just that a when they retired an engine it typically had a broken crank, and their rev limit was 8750. Same goes for "valve float". I spent the better part of my time searching these boars and the internet before commenting in this thread. The original question in this thread was about 8000. The necro-revival of this thread was about similar, and in either cases I found it doubtful it was about season tracking the car and living its life in the 8000+ range. To enter the conversation and tell people they need to worry about there crank can seem absurd. We have no evidence you need to worry about your crank in the low 8000s with the type of use the engine is most likely going to see. Valve float, maybe. Rod bolts? According to a reputable shop it is an issue. Oil pump, for sure, we all should know that (though dry sump is not the only answer or the correct one depending on the engine's use).

The data is not always out there sometimes. Sometimes you have to wear on people's nerves to get information that they themselves might think is out there.

Mate, I have been involved in motorsport for over 40 years, and I learned a long time ago that "engineering" solutions to avoid problems is a lot cheaper than engine rebuilds.

You are talking to a guy who broke 3 engines in a single season back in the 80's and they were 8-10k each in $'s of the day - maybe 2.5 times that now.

IMHO, it is well worth investing in components to eliminate sources of failure and lifing components appropriately.

That said - this is feedback from a hard-core racer - and for anyone beating on rtheir daily for 15 seconds at a time - maybe you can ignore it.

If you are regularly tracking your car and it spends more than 20 seconds per minute at WoT, then maybe you can benefit from my experience.

Doran racing and JWT (their engine builders) will both tell you that OEM cranks crack quickly at 8000+rpm and rod-bolts are a weak point in the OEM engine - do they fail - no, BUT if there is a crack - it will fail in an unpredictable time. The engineers solution is to change it once a crack shows

I'm more than happy to be ignored - but feel bound to put my hard-won knowledge out there if it can help others which I think is the purpsoe of a forum like this one.

Happy for the dissenters to dissent but am perfectly comfortable with my views.

So the biggest problem you're encountering is the guys that are doing this kind of crazy work to the Z are still very few and very far between out of a very small total number of Z owners to begin with. Plus not all of them are even on this forum. Some of them were active at one time or another but they weren't posting extreme details on their build mainly because they were busy af and also they understand that there are very few people interested in the extreme cost of these builds.

A lot of the available information that has been presented comes directly from race teams, not common enthusiasts. Gotta have results to avoid speculation, and there just aren't that many out there. So you have to take a few people at their word based on their experience :twocents:

Food for thought. Fund the frontier my friend. Sign up for tracks day beat the crap out of it for a season if it last, tear down the motor inspect every part, document it. Rebuild it and see what part fails again. Like others have stated mostly race teams have gone this route. Most people don’t want to fund the R&D. If you watch grid life static 370z has a 8k redline, at the end of the season ask him how his motor held up, curious if he will tear down the motor to inspect any failures starting to arise or will he just run it until it blows up or when it blows up will he take the time to inspect everything and share his experience or like most will he just junk the motor.

If in doubt, simply ask the other person for further evidence.

Do not assume “no known failure” to equal “no failure” or “won’t fail”.

It is really simple. Lay your money on the table and take your chances. Then you can see what breaks. If you want the experience and proof you have to PAY for it. Either by someone else's knowledge or your own actual experience. I don't think we have that to worry about though, you aren't going to do anything.

What it comes down to is this with stock crank and 8K redline with a N/A motor.

DD, canyon play toy. Where you might see 8K maybe once a week. It will live.

Doing track days a couple times a year. It will live. But the number of track days you do increases. The life shortens.

Track toy. You are on borrowed time.

FI is a different story.

So true.

Kels used a stock 370z crank and revved to 9k. It took the abuse, but he also reported having micro cracks from constant revving past 8k

So simple (a.k.a. - expensive) answer is a built bottom end with billet crank, built non-VVEL heads, BE billet oil pump and ring that sucker out to 9k! The heck with the junior 8k rpm. :driving:

Contact SuckerPunch directly.

It's so funny how people answer questions so aggressively when they don't have any actual experience with it.

I'm proud to say that I've finally done a ton of testing with street driven Z's and raised redlines. 7800-7900 on a completely stock motor that's beat on everyday and it hasn't had a single failure.

I also worked on 1slowZ's car and we revved that thing to 8700 every single day and for 60+ dyno runs (the rev limiter wasn't working as intended as I had it set to 8300 but it was revving higher. That car has JUN cams, stock VVEL and again, no valve float, no cracked crank, and no issues at all.


Cars with upgraded oil pump gears will do 8200 all day just fine, but keep in mind this is strictly for daily driven Zs and not a track car that sees all of it's mileage at WOT and redline.

Didn't 1slowZs motor throw a rod a few months back and now he has a new Z? The one that popped was boosted but stock motor, right? I don't stay up to date with youtubers that much. But I remember a video about that happening.

You left off the most important part, he had a dry sump system. Stock oil pump had been long gone.

This is bigger deal when boosted because of torque numbers and things start to get out of balance quickly with boost. That said with the right parts and a good rune 8k is doable.

Sent from my SM-G965U using Tapatalk

Motor never blew, it's just going to a new home as the car has been converted to awd so it needs turbos now lol

It does have a dry sump and an ati damper which do go a long way to keeping the crank alive.

It's a hit or miss and this is a topic you don't want any misses.
Raising a the redline and tuning for it will move your power band and leave your low/mid range a bit bland.

Then ask yourself where in that rev-range will you see yourself and you can come up with a better answer. Tons of things at play here.

A balanced crank/rods with an ATI and great oil pump clearances should last quite a bit but it's all determined on driver/abuse/tune.

Whoever plans on this should have coolers, damper, tune and should open their filters.

Rev should be determined on Rod/stroke ratio + mods + tune. Even then it's not a guarantee.

It appears the VHR has a 1.72 ratio (if math is right)
For better comparision:
Honda K24s have a 1.54 ratio and with a type S pump they are usually revved to 8k
While it's younger brother the K20 has a 1.62 ratio and these are take to 9k every day.
The odd child would be the F20c with a ratio of 1.81 and these are production engines with a standard 9k rev limit.

I understand that how some may feel about Hondas however these high revvers can provide great info at that ratio as long as everything else holds 8k should be feasible.

Definitely have you confused with someone else then. My bad. On another note, you converted a 370 to AWD? That's sick! Link to build please?

If you want a rev high vq engine talk Jim Wolf. Valkyrie Autosport runs one that is stroked with a HR head and rev to 9k. Sasha runs one in his hybrid 350. They are bada$$ motors. Valkyrie got five year of race use and they pretty much only do endurance racing.

Sent from my SM-G965U using Tapatalk

honestly in my experience the best reason not to raise the rev limit on the z is that the trans is garbage at high rev's it shifts like crap past 7000 and the synchros cant handle it. once liberty actually releases their cd009 faceplates that wont be a problem anymore but they are already a year behind on it. other reasons to not rev out a z is there is little to no support for the induction system to actually work up there. you fight the vvel and ecu, cams are expensive, you have to deal with the oil pump which requires tearing the whole motor apart, and all the manifolds on the market don't make appreciable power past 7800. torque starts dropping like a rock. if you look at the dynos from my car vs the dynos from soho's stroker you can see we made roughly the same hp but the curves are massively different.

its not in a build thread yet. i tend to finish a car first then spend a couple days making a massive build post then drop it and you guys go nuts.

You're correct. I'm already planning to go nuts!

Agreed! The motors I mentioned are all mated to sequential transmissions. I have all the upgrades to run at 8k but Seb tunes it to 7200. I generally shift at 6800 to 7000 because of said issues.

Sent from my SM-G965U using Tapatalk

We already know that you are nuts. Just need a push to go over the edge.

Valid points, the CD will suffer for sure and after all of what we have discussed there are more cons than pros on a goal oriented car.

Street car from 1-3rd it might be as survivable as a monitored coolant leak.

That's why I was so gung ho on the liberty faceplates. I was even getting ready and buying tools to do the install for guys and then they told me they weren't ready to release the parts and had to do it in house at $2300/box and that was a heavily discounted rate. I'm on the call back list for when they actually decide to sell parts

According to their standard pricing a dog engagement z box once it comes to market is sub $1000 for 1-4gear in parts

Also they have a 6+month lead time. You're not gonna sell **** at that rate :rolleyes: I was going to buy 3 transmission's worth of parts and had to pass beacuse no way In hell am I waiting that long for 24 parts

This is the real reason I cancelled my plans to do a sequential conversion on the cd009 box. I have the linkage and shift spools drawn up but it isn't worth **** if I can't get affordable dog gears