BigJae46,
First I would like to apologize for the long post because there so much to
consider. Easy to add 300rpm but not so easy to consider the actual facts.
If I were you I would do the following based on the data you have provided.
I put together some numbers for you perhaps you will like my suggestion
something that works well from my end.
On the rev limiter: Do not raise your rev limiter pass 8100rpm-(8200rpm pushing it)....
on a std S54 is darn drought to the limit from the factory at 7900rpm.
On a production line engines as S54 is the Balancing on the parts is
not "Race-Balanced" The pistons from factory I have measure are very
close between each other but the piston is not so light for you to increase
the revs by 600rpm, rods are also not exactly light for its length at 139mm.
One should understand that every 100rpm pass 7900rpm as the factory
rev limiter the ware of the engine at 8500 increases by almost 20-30%
the 1.52rod ratio wants to rape the side wall and cog it.
Those who have tune and share "Bro on my daily I rev to 8500rpm bro and
no problem"... sure you are doing it ones twice and for very short time...track
engine do stay a lot of time in hi Harmonics...window....and the stress of the
parts are quadruple compared to the "Bro" cruising in NY City at 2am from idle to
8500 and next light slow down because cop is behind us....
So the 600rpm does not sound by much but you will
ware out the engine more than if keeping at around std rev limiter.
The abused S54s I have seen apart which were revved pass 7900rpm, most have
shredded damper aligning pin which is pressed inside at the nose of the frank.
This is because the Second Order Harmonics are going so violent back and
forth that the 4 torx bolts can not hold the damper in place and the damper
slip so little that holds on the pin and then the pin brakes till the damper rests
on the 4 bolts.
The damper itself from heat cycles the Elastomer dries out and its changing
the wide Frequency which has been tune from the factory and no longer support
that.
BMW MS and PTG Team never ever revved more than 8400 on a soft cut and
hard is at max 8500rpm.
When you push anything pass 7900rpm- 8500rpm-9000rpm Dynamics balancing
is absolute critical,pistons, rods, small end big end etc...must be as light as possible
and balanced.
There is a single downside of having oil squirters is that they spray so much oil
under the piston crown to cool it down that the oil gets stuck there as a film on the
rods pours because they are cast...that this makes the parts little off balance. Part
reason why Dry-Sump system is very helpful on this part and pulling the oil from the
parts via suction and also the vacuum and sucking the oil which is splashing all over
the crank, rods, pistons..etc...
Every New Sachs Kits I install on engines I always sent for balancing and always comes
somewhere between 10-18grams off that is a lot...18here, 4 there, 1 elsewhere.....and
when you combine it becomes one rattle box of parts.
When we had the track E46M3 I installed solid (delrin) engine mounts and tranny
and pass 7900rpm to 8300rpm the engine vibrations were so loud in the tranny tunnel
it felt like the guts are all falling on pieces....then had to back up the revs 8000rpm
I would not pass 8100rpm on std S54 max if you want to have long lasting engine.
Gearing: I know exactly what are you asking from the engine at the track when you
want say need the rev higher so that you will hold on one gear and avoid shifting.
Note, the charts I made for you and take this numbers and compare it to your telemetry
track info.
By rising the rev limiter as you aim so that you don't shift you are going to gain very
little...1mph here 1mph there....
If I were you I would put 4.27 ring and pinion. Why ? sounds absurd but in real world
your car will be faster because the 4 and 5th gap is very nice and close. 3rd gear will
be used in low speed corners which is great because it will act like tall 1st gear as on
all race gear boxes and ones you accelerate 4th gear rpm drop will be small and then
on 5th gear the rpm drop will be right closer to Pick-HP and then at the end of the straight
you will reach your top speed right bro the rev limiter.
Hi speed like 100mph-120mhp+ one needs power to fight the air drag. Look at Dodge Viper
ACR at the curb weight as the E46M3 std can't reach 300km/h-180mph due to its massive
aero, an engine that is almost 2.5 times the size of an S54 and massive 650hp or so.
Our BMW engines are hi revving and one need relatively short gearing and very little rpm
drop so that to fight the drag.
Don't forget in race gear box all the gears are used at the track. Not sure if you have driven
Laguna Seca but the GTRs were filling up 5th gear at this given short straight....
So in your case you will same as now 3rd 4th and 5th I assume is why you are asking to rev higher
so that you don't up-shift to stay on 4th gear ? or you upshift in 5th before. I assume your engine is
tuned and your power has been shifted to the right aka up top.
With 4.27 even at low speed off a corner you will be right "In-Cam" 4500-5000rpm so your window
range will be all out usable and the S54 will be always in easy to pull hard on the revs.
Take look the charts and lets look at it together, share more info from the track telemetry.
such as what is the slowest corner at Cota let say.
Note in Blue the RPM drop between gears. 4.27 is "Win-Win"
Regards,
Anri
3,62
3.91
4.27
First I would like to apologize for the long post because there so much to
consider. Easy to add 300rpm but not so easy to consider the actual facts.
If I were you I would do the following based on the data you have provided.
I put together some numbers for you perhaps you will like my suggestion
something that works well from my end.
On the rev limiter: Do not raise your rev limiter pass 8100rpm-(8200rpm pushing it)....
on a std S54 is darn drought to the limit from the factory at 7900rpm.
On a production line engines as S54 is the Balancing on the parts is
not "Race-Balanced" The pistons from factory I have measure are very
close between each other but the piston is not so light for you to increase
the revs by 600rpm, rods are also not exactly light for its length at 139mm.
One should understand that every 100rpm pass 7900rpm as the factory
rev limiter the ware of the engine at 8500 increases by almost 20-30%
the 1.52rod ratio wants to rape the side wall and cog it.
Those who have tune and share "Bro on my daily I rev to 8500rpm bro and
no problem"... sure you are doing it ones twice and for very short time...track
engine do stay a lot of time in hi Harmonics...window....and the stress of the
parts are quadruple compared to the "Bro" cruising in NY City at 2am from idle to
8500 and next light slow down because cop is behind us....
So the 600rpm does not sound by much but you will
ware out the engine more than if keeping at around std rev limiter.
The abused S54s I have seen apart which were revved pass 7900rpm, most have
shredded damper aligning pin which is pressed inside at the nose of the frank.
This is because the Second Order Harmonics are going so violent back and
forth that the 4 torx bolts can not hold the damper in place and the damper
slip so little that holds on the pin and then the pin brakes till the damper rests
on the 4 bolts.
The damper itself from heat cycles the Elastomer dries out and its changing
the wide Frequency which has been tune from the factory and no longer support
that.
BMW MS and PTG Team never ever revved more than 8400 on a soft cut and
hard is at max 8500rpm.
When you push anything pass 7900rpm- 8500rpm-9000rpm Dynamics balancing
is absolute critical,pistons, rods, small end big end etc...must be as light as possible
and balanced.
There is a single downside of having oil squirters is that they spray so much oil
under the piston crown to cool it down that the oil gets stuck there as a film on the
rods pours because they are cast...that this makes the parts little off balance. Part
reason why Dry-Sump system is very helpful on this part and pulling the oil from the
parts via suction and also the vacuum and sucking the oil which is splashing all over
the crank, rods, pistons..etc...
Every New Sachs Kits I install on engines I always sent for balancing and always comes
somewhere between 10-18grams off that is a lot...18here, 4 there, 1 elsewhere.....and
when you combine it becomes one rattle box of parts.
When we had the track E46M3 I installed solid (delrin) engine mounts and tranny
and pass 7900rpm to 8300rpm the engine vibrations were so loud in the tranny tunnel
it felt like the guts are all falling on pieces....then had to back up the revs 8000rpm
I would not pass 8100rpm on std S54 max if you want to have long lasting engine.
Gearing: I know exactly what are you asking from the engine at the track when you
want say need the rev higher so that you will hold on one gear and avoid shifting.
Note, the charts I made for you and take this numbers and compare it to your telemetry
track info.
By rising the rev limiter as you aim so that you don't shift you are going to gain very
little...1mph here 1mph there....
If I were you I would put 4.27 ring and pinion. Why ? sounds absurd but in real world
your car will be faster because the 4 and 5th gap is very nice and close. 3rd gear will
be used in low speed corners which is great because it will act like tall 1st gear as on
all race gear boxes and ones you accelerate 4th gear rpm drop will be small and then
on 5th gear the rpm drop will be right closer to Pick-HP and then at the end of the straight
you will reach your top speed right bro the rev limiter.
Hi speed like 100mph-120mhp+ one needs power to fight the air drag. Look at Dodge Viper
ACR at the curb weight as the E46M3 std can't reach 300km/h-180mph due to its massive
aero, an engine that is almost 2.5 times the size of an S54 and massive 650hp or so.
Our BMW engines are hi revving and one need relatively short gearing and very little rpm
drop so that to fight the drag.
Don't forget in race gear box all the gears are used at the track. Not sure if you have driven
Laguna Seca but the GTRs were filling up 5th gear at this given short straight....
So in your case you will same as now 3rd 4th and 5th I assume is why you are asking to rev higher
so that you don't up-shift to stay on 4th gear ? or you upshift in 5th before. I assume your engine is
tuned and your power has been shifted to the right aka up top.
With 4.27 even at low speed off a corner you will be right "In-Cam" 4500-5000rpm so your window
range will be all out usable and the S54 will be always in easy to pull hard on the revs.
Take look the charts and lets look at it together, share more info from the track telemetry.
such as what is the slowest corner at Cota let say.
Note in Blue the RPM drop between gears. 4.27 is "Win-Win"
Regards,
Anri
3,62
3.91
4.27
Comment