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-   -   M54B25 7500 RPM limit (http://forum.e46fanatics.com/showthread.php?t=893486)

e60fan 12-24-2011 12:52 PM

M54B25 7500 RPM limit
 
Is it safe, what do you think? Not to rev up to 7500 every day and stay in 7000 RPM for a long time, but for some situations when you must upshift later ;)

I heared a point of view from bmw tuners that it's safety on stock cams but useless unless you go to higher degree cams and I wanna to install them from B30 with instake manifold, DISA and throttle body later.

P.S. I read that something may be wrong with oil pump at high revs? If this so serious problem and can't be solved myself without special parts I'm thinking about VAC - M52tu/M54tu Oil Pump Upgrade Kit.

lejeunebimmer 12-24-2011 12:55 PM

Since you're too lazy to search.

NOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Iceman00 12-24-2011 12:55 PM

Quote:

Originally Posted by e60fan (Post 13919326)
Is it safe, what do you think? Not to rev up to 7500 every day and stay in 7000 RPM for a long time, but for some situations when you must upshift later ;)

I heared a point of view from bmw tuners that it's safety on stock cams but useless unless you go to higher degree cams and I wanna to install them from B30 with instake manifold, DISA and throttle body later.

P.S. I read that something may be wrong with oil pump at high revs? If this so serious problem and can't be solved myself without special parts I'm thinking about VAC - M52tu/M54tu Oil Pump Upgrade Kit.

Buy and install the cams and manifold first. Generally there is such a large drop off at that high, there is no point in being up there. THe best thing to do is shift at 7000rpm. If your set on going that high, I'd consider upgrading the valve springs and retainers, going with the ATI harmonic damper and upgrading your oil pump.

tinkwithanr 12-24-2011 01:53 PM

+1, Unless your going to be doing a lot head work to improve flow there really isn't a point in revving that high. The power drops off pretty quickly.

e60fan 12-24-2011 02:06 PM

Quote:

Originally Posted by Iceman00 (Post 13919334)
Buy and install the cams and manifold first. Generally there is such a large drop off at that high, there is no point in being up there. THe best thing to do is shift at 7000rpm. If your set on going that high, I'd consider upgrading the valve springs and retainers, going with the ATI harmonic damper and upgrading your oil pump.

I need only intake cam with 240 degree and I have it lying on the floor - exhaust cam is 244 degree already, I have e60 with M54B25. Now I'm waiting complete intake manifold so everything will be installed at once. Also I want to buy lighweight JBR flywheel.
When I would like to do a small drag race higher RPMs is preferable because I will be with every upshift in higher power band.

What about compromise - 7200 RPM?
Also with 7000 RPM rev limiter do I need ATI damper & upgrade oil pump? It's important to know at what RPMs oil pump failure happens.

Thank you for the info, you're great guy, I read your posts and dyno graphs are awesome! :)

e60fan 12-24-2011 02:11 PM

Quote:

Originally Posted by tinkwithanr (Post 13919491)
+1, Unless your going to be doing a lot head work to improve flow there really isn't a point in revving that high. The power drops off pretty quickly.

Head porting and polishing will be in future with ESS TS3 :evil:

But what about shricks that installed at stock head and they make 7400-7500 RPM rev limit?

So you guys adviced me to do 7000 RPM, this is the best variant for high power output and high safety of engine?

e60fan 12-24-2011 02:16 PM

Quote:

Originally Posted by lejeunebimmer (Post 13919332)
Since you're too lazy to search.

NOOOOOOOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

research was done but when you asked somebody it better to think:pfft:

e60fan 12-24-2011 02:52 PM

more searching and found that my 2.5L is free from harmonics, so I don't need ATI dampers and probably don't have problem with oil pump failure
http://forum.e46fanatics.com/showpos...4&postcount=15
also it's a question about oil pump failure in my case, I have later production 2004 year of 525i when it may be was fixed

so I'm thinking about 7200 RPM limit now :)

3coupe 12-24-2011 03:26 PM

Quote:

Originally Posted by e60fan (Post 13919576)
more searching and found that my 2.5L is free from harmonics, so I don't need ATI dampers and probably don't have problem with oil pump failure
http://forum.e46fanatics.com/showpos...4&postcount=15
also it's a question about oil pump failure in my case, I have later production 2004 year when it may be was fixed

so I'm thinking about 7200 RPM limit now :)

You need to honestly do a lot more research. The harmonics are because of the cams in the b30. It also mainly effects people that track their car and hold the 6000 rpm range.

You also need different cams for FI. Actually for the TS3 you should get the cams from from ESS.

And upgrading your oil pump is also a smart idea. I would highly recommend it with all the mods you plan to do. Read through this thread. http://forum.e46fanatics.com/showthr...&highlight=opn

Rob43 12-24-2011 03:33 PM

Quote:

Originally Posted by 3coupe (Post 13919631)
You need to honestly do a lot more research. The harmonics are because of the cams in the b30. It also mainly effects people that track their car and hold the 6000 rpm range.

You also need different cams for FI. Actually for the TS3 you should get the cams from from ESS.

And upgrading your oil pump is also a smart idea. I would highly recommend it with all the mods you plan to do. Read through this thread. http://forum.e46fanatics.com/showthr...&highlight=opn


This is not true or accurate, please research things before you post them as factual.

Rob43 12-24-2011 03:42 PM

OP,

If you really want to Rev to 7500 RPM, or at least pretty close you'll need a solid lifter valve train (expensive). Not to mention a "tune" that will allow it.


There's a wealth of excellent resources on the forum concerning your question, please take 3 to 6 hours of your time and read everything you find.



Good luck.

3coupe 12-24-2011 03:43 PM

Quote:

Originally Posted by Rob43 (Post 13919641)
This is not true or accurate, please research things before you post them as factual.

I'm pretty sure I have read that in multiple places on here, but maybe I'm wrong.

Your answer on the other hand is so very helpful to the OP. Maybe instead of just bashing me for trying to help someone you can actually give the OP the correct answer.

Hermes 12-24-2011 04:04 PM

S54 swap and call it a day

lejeunebimmer 12-24-2011 07:15 PM

Quote:

Originally Posted by 3coupe (Post 13919661)
I'm pretty sure I have read that in multiple places on here, but maybe I'm wrong.

Your answer on the other hand is so very helpful to the OP. Maybe instead of just bashing me for trying to help someone you can actually give the OP the correct answer.

Where you went wrong was the cams. Its not the cams that cause it.

Its a combination of the s52 crank used in the b30 and a couple of other things.

To the op. If you want to rev that high you're going to need more than 240 244 cams start looking at about 264 252 or even 272 264. They will put more power up top of rpm band and make the 7500 rpm redline more beneficial to you. As it is right now your motor will pretty much fall flat on its face at about 6k rpm although a 7k rpm redline will put you into the meatier part of your powerband when you shift. Hence why it is common to see 7k on slightly modded motors.

Also it is important to know that your hydralic lifter cannot safely handle 7500rpm as valve float begins around 7300 to 7500 on these motors hence my original answer of no.

You will need to rebuild your top to handle and make power at this increased rpm range, and although the b25 doesn't suffer the harmonics of the b30 it is still very advisable to put an ati super damper on if you will be revving to 7.5k your motor will thank you for it.

Sent from my SPH-M900 using Bimmer

lejeunebimmer 12-24-2011 07:18 PM

Quote:

Originally Posted by lejeunebimmer (Post 13920048)
Where you went wrong was the cams. Its not the cams that cause it.

Its a combination of the s52 crank used in the b30 and a couple of other things.

To the op. If you want to rev that high you're going to need more than 240 244 cams start looking at about 264 252 or even 272 264. They will put more power up top of rpm band and make the 7500 rpm redline more beneficial to you. As it is right now your motor will pretty much fall flat on its face at about 6k rpm although a 7k rpm redline will put you into the meatier part of your powerband. Hence why it is common to see 7k on slightly modded motors.

Also it is important to know that your hydralic lifter cannot safely handle 7500rpm as valve float begins around 7300 to 7500 on these motors hence my original answer of no.

You will need to rebuild your top to handle and make power at this increased rpm range, and although the b25 doesn't suffer the harmonics of the b30 it is still very advisable to put an ati super damper on if you will be revving to 7.5k your motor will thank you for it.

Sent from my SPH-M900 using Bimmer



Sent from my SPH-M900 using Bimmer

Iceman00 12-24-2011 07:52 PM

It's a combination of the crank and probably the aluminum block the M series motor is made out of. This is unlike the S54 which is iron AND reinforced. (The S52 is iron as well, and can see more revs before it sees the same failures.) Of course, that is MY hypothesis.

The major issue on this car is the head, which really doesn't flow that well, (The N series motors are worse, and fall flat on their face after 5500rpm) and then there are dinky cams which don't help matters. If you really want to be a high rev hero, you need to address those weakness first and then look at ways to make the car reliable. I've heard of OPN failures on the M52 block with the smaller displacement motors (rare) and also have heard of valvespring/retainer issues. Hydraulic lifters aren't really a problem from what I've seen.

Rob43 12-24-2011 10:35 PM

Quote:

Originally Posted by Iceman00 (Post 13920091)
It's a combination of the CRANK and probably the ALUMINUM BLOCK the non (fixed) M series motor is made out of. This is unlike the S54 which is iron AND reinforced. (The S52 is iron as well, and can see more revs before it sees the same failures.) Of course, that is MY hypothesis.......


Spot on.

MSportBMW 12-25-2011 12:43 AM

I think if you want more revs with the M54 you should just get some Shrick 264/248 with a custom tune. Else you will spend quite a bit of money trying to get high revs reliably out of the M54 platform. You should just swap in a S54 motor if you want high rev and reliability

e60fan 12-25-2011 01:16 AM

Thanks to all for answers! I decided to go with 7200 RPM limit as I read **** happens at 7300-7400 and higher.

About 240 intake cam - if I can find somebody in EU or Eastern Asia who can regrind it to 260 degree (so my combo will be 260/244) it would make me happy, but as I understand it will be not compatible with FI for example ESS TS2.

P.S. VAC - M52tu/M54tu Oil Pump Upgrade Kit seems not working as I noticed at forum

lejeunebimmer 12-25-2011 11:17 AM

Quote:

Originally Posted by e60fan (Post 13920593)
Thanks to all for answers! I decided to go with 7200 RPM limit as I read **** happens at 7300-7400 and higher.

About 240 intake cam - if I can find somebody in EU or Eastern Asia who can regrind it to 260 degree (so my combo will be 260/244) it would make me happy, but as I understand it will be not compatible with FI for example ESS TS2.

P.S. VAC - M52tu/M54tu Oil Pump Upgrade Kit seems not working as I noticed at forum

VAC Kit doesnt really keep it from backing off, but in a b25 application with an ati damper it should be suffiecent.

260/244 is not great for f/i you'e going to want more exhaust than intake, but fi tuning is another game entirely from what I know.

260 intake with only 248 exhaust would make power but you'd be better off going with the schricks (or regrind a copy of them) so 264/248 or even better 264/252.

Glad to see you did a little bit more homework about it.


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