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GTR Dreamer
07-10-2004, 04:13 PM
Does anyone know a way to increase the redline, ive heard it has something to do with the intake plenum and i guess lightweight internals. it seams like a weird topic but surely theres someway to increase the engines red-line.

Matra et Alpine
07-10-2004, 04:56 PM
Does anyone know a way to increase the redline, ive heard it has something to do with the intake plenum and i guess lightweight internals. it seams like a weird topic but surely theres someway to increase the engines red-line.
Intake needs to breath a LOT more air/fuel for higher revs, so porting and polishing are important.
Likewise the exhaust otherwise back-pressure prevents the exhaust stroke priming the intake stroke.

Then the valves may have to be sized larger or opened further to allow the gasses to move in and out of the chambers more quickly to match the higher revs.

Beyond that a faster revving engine needs to address the reciprocating mass. So the bits that change direction need to become as light as possible.

Pistons, conrods, crank. They all also need balanced to ensure they don't vibrate themselves apart at the higher revs.

Reducing the stroke helps - but needs increased compression or bore to make up for lost power.

Then the valves need stronger springs to be able to follow the cam profile during valve closure. Lighter valves are important to improve their velocity and need to be stronger to cope with the higher stresses of stronger springs. The stronger springs also help prevent valve bounce. ( Desmodronic gear drive removes the need for all this but hasnt' been used successfully in street car engines the way the Ducati bikes have managed. Just don't talk service costs :) )

Get any decent engine tuning book from the library and it will go through all the options.
There are tuning books published for the majority of engines suitable for tuning. Each engine has idiosyncracies about what is successful and what leads to failure in all the areas above. Further readoing of those would now be recommended :)

Ferrari Tifosi
07-10-2004, 08:41 PM
Matra covered everything I was going to say.

megotmea7
07-10-2004, 11:38 PM
Matra covered everything I was going to say.
everything but...


to make yor average ROTARY powered car essentially spin faster first you have to address the fuel needs (we'll say an FD for simplicitys sake) the FD's fuel system wouldnt be capable of supporting much of anything above 8000rpm(stock redline) so fuel pump, regulator, and may as well geta new high flow fuel filter while your at it(stock unit is the same used on a miata :() large injuectors may be needed depending on how far your going to take it. now a stand alone engine managment is a must not only for the higher rpm support but for he tuning also(note: powerFC does ot support anything but stock reline, the newest haltec unit(EK6 i belive) would be best). next the engine should be ported to take advantage of the higer level of breathing(not only for higher volumes of air but "opening and "closing" timing of the ports. think cam profiles and timing on a piston engine). after thats all said and done your engine would be perfectly capable of 10krpm BUT you need bigger turbo(s) the stock units would be HIGHLY overworked at any respectable pressure at these rpm's creating higher compressor output temps increasing detonation so new turbo sized for what you want. now that ts capable of anywere from 10-12krpm you have to worry about a whole new set of issues(goes fot the piston engines also) the flywheel/clutch assembly is very capable of coming apart at speed ad ripping your car to shreds from the inside out, at about 9krpm on an FD i would look into a scatter sheild unless your feeling lucky ;) as for your flywheel and clutch see whats been tested, every car is different the FD's flywheel is capable of pretty much anything you can throw at it, th stock clutch a been know to come apart at a touch above 9krpm, so look to the aftermarket for this(again see whats been tested. now your all set the only thing you have to worry about now is tuning (can be a bitch) and your tranny input shaft(ive heard of premature tranny failure on some cars, i dont know what the FD tranny is capable of its pretty stout(exept for the 5th gear syncro... :() but you never know. most of the time a higher redline is used to increase the powerband on cars fitted with larger turbo's that dont spool til almost redline, or on n/a cars as a different way to make horsepower(just carry the torque curve up in the rpm and make more power, lower rpm power is bound to suffer tho. personaly i cant see the point on a street car buy meh, mabe you just want a cool sound... :rolleyes:

Matra et Alpine
07-11-2004, 04:24 AM
Forgot about fuel :)

Everything MM7 said about pump, injectors etc goes.

I'd not bothered about clutch/tranny as it was revs he wnted.
Now raise the POWER or TORQUE curve and there's LOTS more to worry about.

But as they usually go hand-in-hand with any performance increase, everythin MM7 said about clutch/tranny goes too :)

megotmea7
07-24-2004, 02:06 AM
your welcome :)