I´m thinking about chipping my 325ic
Do you recommend chips that put the revlimiter over 6000 rpm?
What things do i need to think about when I rev the engine harder
Higer revs on m20b25
Moderator: martauto
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Fushion_Julz
- E30 Zone Camper
- Posts: 1295
- Joined: Tue Jun 07, 2005 11:00 pm
- Location: Blackwater
Rev limiter is set to 6500, IIRC, on the 325i.
How high do you want it to go?
Using standard AFM and TB, std cam, ports, exhaust, etc, the maximum power is produced under the max revs (at around 5750rpm). So increasing the rev limit MAY allow it to rev higher, but to no real benefit as you are just moving further out of the power band.
If you modify the breathing, then the power may well go up as the revs go up...Only you then need to consider the strength of the bottom end. I have mine set to 6750rpm, on the advice of Jayson...However, I hardly ever hit the rev limiter as the rest of the motor is in good nick, but standard.
I would not want to take a standard bottom end past 7000rpm, in any case...You will need to balance all moving parts, at the very least, and check the condition of the bearings, to be safe past that...Much over 7500-8000 and you'll need a very strong crank and rods!
A better mod is to lighten the flywheel a sensible amount as this will improve response...
How high do you want it to go?
Using standard AFM and TB, std cam, ports, exhaust, etc, the maximum power is produced under the max revs (at around 5750rpm). So increasing the rev limit MAY allow it to rev higher, but to no real benefit as you are just moving further out of the power band.
If you modify the breathing, then the power may well go up as the revs go up...Only you then need to consider the strength of the bottom end. I have mine set to 6750rpm, on the advice of Jayson...However, I hardly ever hit the rev limiter as the rest of the motor is in good nick, but standard.
I would not want to take a standard bottom end past 7000rpm, in any case...You will need to balance all moving parts, at the very least, and check the condition of the bearings, to be safe past that...Much over 7500-8000 and you'll need a very strong crank and rods!
A better mod is to lighten the flywheel a sensible amount as this will improve response...
1987 Henna Rot M3 (was 195bhp CAT..now more and no cat)
2001 E46 330i SE Touring (manual)
2001 E46 330i SE Touring (manual)
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Brianmoooore
- E30 Zone Team Member
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- Joined: Mon Jan 10, 2005 11:00 pm
My 250,000 mile LPG powered touring doesn't have a rev limiter, since the limiter cuts the injectors, which I don't use.
Often gets buzzed way past 7000 in second and third gears when I'm overtaking and not concentrating on the tacho.
Hasn't gone bang yet!
Often gets buzzed way past 7000 in second and third gears when I'm overtaking and not concentrating on the tacho.
Hasn't gone bang yet!
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g57yle
- Boost Junkie
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- Joined: Wed Jan 19, 2005 11:00 pm
- Location: East London
i revved my 325i to over 8000rpm but like Fushion_Julz says theres no real point as it doesnt really make any more power and doesnt do any good for engine. i would keep 6750 as a limiter. and that would be fine.
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Turbo-Brown
- Boost Junkie
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- Location: Aldershot, Hants
Mmmmm, interesting stuff!
Seems that the recommended 6400rpm absolute max from the hand book can be stretched a little bit.
Zis is goot! I need some more revs!
Don't suppose anyone's got the hand book from a facelift car which might say what the max revs for the later 2.5 engine are have they?
Apparently the early pistons are heavier so it could well be that the earlier engines really shouldn't rev any higher!
Cheers!
Alex
Seems that the recommended 6400rpm absolute max from the hand book can be stretched a little bit.
Zis is goot! I need some more revs!
Don't suppose anyone's got the hand book from a facelift car which might say what the max revs for the later 2.5 engine are have they?
Apparently the early pistons are heavier so it could well be that the earlier engines really shouldn't rev any higher!
Cheers!
Alex
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