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Discussion Starter #1 (Edited)
What is the maximum safe RPM for a D17 with Forged Rods/Vitara pistons (I'll make them fit)?
Why can't it be revved higher?
Forces on the pistons/high piston speeds?
What would revving higher damage? Increased wear between the piston/wall?
Damaging the pistons (like in the one vitara thread?)?
 

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McLOVIN
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Id say 8000 is feasible as longas you use arp rod bolts. But remember that the cylindwrhead/camshaft\valvesprings need to be up to that kinda of rpm. Although woth vitaras I think tje motor becomes non interference LOL
 

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the real question is where does the car make peak power, and when does it start to fall off.. bearing clearances are also important when your building a motor that will see high rpms because of a big turbo or something.. if your car makes peak power at 6k, there is no reason to rev it beyond 7k... if your doing it just for gearing issues, well then you need to focus on gearing, and not revving the motor to compensate for shitty gearing
 

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the real question is where does the car make peak power, and when does it start to fall off.. bearing clearances are also important when your building a motor that will see high rpms because of a big turbo or something.. if your car makes peak power at 6k, there is no reason to rev it beyond 7k... if your doing it just for gearing issues, well then you need to focus on gearing, and not revving the motor to compensate for shitty gearing
thank you for not making me write this.
 

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Discussion Starter #5
the real question is where does the car make peak power, and when does it start to fall off.. bearing clearances are also important when your building a motor that will see high rpms because of a big turbo or something.. if your car makes peak power at 6k, there is no reason to rev it beyond 7k... if your doing it just for gearing issues, well then you need to focus on gearing, and not revving the motor to compensate for shitty gearing
Don't want to say big turbo, but shooting for maybe 400whp.

Still a engine noob, so I just toying with thoughts. :sweatdrop:
 

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Limits are maximum piston speed and acceleration rates due to length of stroke and rod length. Short rods change angle faster and accelerate the piston away from TDC faster. They also increase side load against the skirt.

When the D16 vtecs and DOHC engines where introduced, they had the highest piston speeds of any production engine at the time. There are still only a few engines that have higher piston speeds at redline. Increasing the stroke also of course increases piston speed at the same rpm.

Of course a turbo, head and cam all come into play and help determine what rpm you need to get best performance.
 

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Excessive piston speed chokes power past a certain point as the charge can't burn fast enough to build pressure fast enough, but that is at more like F1 speeds.

Excessive piston speed also breaks rod bolts and cracks pistons at the skirt, or at the base of the oil ring groves. It can also break pins or pin bosses or even pound out little ends. It can also pop circlips out and the pin scores the bore if the pins flex to much.
 

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Don't want to say big turbo, but shooting for maybe 400whp.

Still a engine noob, so I just toying with thoughts. :sweatdrop:

even having a hp goal doesnt tell you how high you have to rev it...

you will need to put it on the dyno. thats the only way to figure out where your set-up likes it best and where to set the rev limiter. BUT if you have stock valve springs and dont plan on upgrading them, your limited to 7200-7800 rpms. 7200 on the safe side.
 

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Discussion Starter #11
even having a hp goal doesnt tell you how high you have to rev it...

you will need to put it on the dyno. thats the only way to figure out where your set-up likes it best and where to set the rev limiter. BUT if you have stock valve springs and dont plan on upgrading them, your limited to 7200-7800 rpms. 7200 on the safe side.
I know. Different turbo, different powerband. Different set-up, different spool times, different powerbands, different different different.

Say with a T3/T04E 57 Trim (.63ar). They make maybe 200whp at around 4700rpm on D16's. Maybe 300whp at crossover, and maybe 400whp at 6700, some hold 400whp to 8k+ (and why shift if your making good power, well, until the limits of the engine?). Don't know how those numbers would change/move around with a D17 build.

But assume upgraded valve springs, and possibly cam.
I've seen Pat mention that 7000rpm+ is asking alot from a D17. I've also seen the thread with the D16/Vitara's that were cracking, which I would be worried about in a D17. But I can't see the D17 spooling/making power that much earlier than a D16, that you don't need to rev it as high. Am I correct?
 

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in the 4g63 of my friends in our little car club, the crower stroker kit he got installed lowered peak boost by about 400-500 rpms. but thats .4 liters difference where as your talking .1 I would say the power curve should be somewhat linear to a d16 but the only way to find out would be the dyno
 

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with MOST daily driveable cams you'll be out of breathe before you hit unsafe revs. even the bisi (kind of SOHC) 3.6 is done by what 8000rpm? i believe the head is pretty close to done by then on stock ports.

dont compare "race" builds or "race" cars to your car. most racers will extend the revs to whatever is needed to get the rpm drop to the next gear just below peak torque.

if you dont run an oversized turbo you wont need a ton of revs to be happy.
 

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Lot's of info being posted in this thread OP. Best I can add is to also find someone with a similar setup as what you're toying around with and go from there. That person might be able to set you in a better path.
 

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uncivic4dr

Apart from the bit of info you posted about rpm and components related to that, this is a very substantial thread jack. Jacking the thread instead of starting your own probably explains your red dot.
 

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I dont understand.
If you want to talk about some other build why dont you make a thread?
Also, you can edit posts. You dont have to keep making one post after another as you think of things to say... unless of course youre just trying to get your post count up, in which case, shame on you.


EDIT:
420 hp at 32 psi!!!
BAHAHAHAHAHA
 

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Leave it, but start your own build thread and only post here what directly relates to the OP or a small diversion. Well at least that's my take on it, but hey, it's not my site.
 

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i had no intention of thread jacking lsbrasil's build thread he is a very nice guy and puts this info out here for us to view and i put it out too help thats all, i no i got bad rep but please dont make it worse for me i honestly wanted to help i will delete it if yall would like.
Only reason you have it is because you blatantly said "Fuck you guys im all most at 65 posts and then i'll be in the for sale thread".............Thats not how we roll here. Good luck to you :bigok:


And O.P on stock valvetrain 7400-7600 max not that most stock cams will even make steady power untill then anyways. My 2.2 made peak power till 8000rpms before it fell flat on its face, I dd that car but all so had Bisi springs on stock retainers so it took a beating.
 
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