How do I build a high revving motor?
08-20-04, 12:39 AM
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How do I build a high revving motor?
If its a possible feat I would like to build a high revving (10,000 - 11,000 rpm) N/A motor. And not to mention a drivetrain to back it up. I'm not to interested in turbocharging or getting the most speed. It would be very pleasing to rap a motor up to 11,000 rpm and widen its powerband quite a bit. What kind of work am I looking at doing and how pricy will it be. I want the motor to make power all the way up to 10,000 rpm and max at 11,000 rpm with a drivetrain that will hold up to it and not have to worry about **** breaking. I didn't think this subject had ben covered so I didn't search. Just today I found it very pleasing to push the car up towards 9000rpm and would like to squeeze out a few more and maybe make a little more power.
08-20-04, 12:56 AM
#2
Porting.
http://home.iprimus.com.au/bluey3/portsPage/ports.htm
The Peripheral port! These engines were even banned in racing
"In June 1971 the Japan Automobile Federation, the sanctioning body of all competition activities in the country, decreed the ban of the peripheral intake port rotary" Rx7 the new Mazda rx-7 and Mazda rotary engine sports cars page 240
The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular – peripheral – intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 350hp but as it is developed for racing, exhibits very poor drivability, fuel consumption and requires an exhaust system deigned to produce excessive noise. Like the J port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components.
"In June 1971 the Japan Automobile Federation, the sanctioning body of all competition activities in the country, decreed the ban of the peripheral intake port rotary" Rx7 the new Mazda rx-7 and Mazda rotary engine sports cars page 240
The peripheral port is the ultimate form of porting for a rotary engine without turning to forced induction. Instead of conventional metal shaping with a grinder, the side ports are actually filled and completely new circular – peripheral – intake ports are fitted directly through the rotor housing and is easily identified on an engine by its tubular intake manifold. This modification has potential for over 350hp but as it is developed for racing, exhibits very poor drivability, fuel consumption and requires an exhaust system deigned to produce excessive noise. Like the J port, the PP produces its maximum power past 8,000rpm creating increased stress and wear on components.
08-20-04, 01:01 AM
#3
Look into a Peripheral or Bridge-Port. Also look into all the supporting mods from vibrations heat and rotating mass all associated with a high revving engine. You are going to need a different flywheel, clutch, etc. Everything is going to need to be able to sustain twice the amount of abuse it is seeing now. Also remember you are going to need a scatter-shield so if you grenade your flywheel it doesn't take your legs with it! Remember as well, by pushing the powerband back into the 11,000 range you are going to also push your usable low end up as well. You won't have usable power until like 3k rpm. There are certainly pros and cons to consider before such an undertaking.
--Fritz
--Fritz
08-20-04, 01:04 AM
#4
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gonna take a little more that porting,... think guru eshaft and a buncha other goodies. It can be done but eshaft flex becomes a real problem beyond ~8.5-9k, hence the shaft. dont forget your modified stat gears, snap ringed rotor gears, higher oil pressure, larger bearing clearences.... theres other stuff i cant think of rite now,.. 9k is a much cheaper goal. The guys at ausrotary.com have pretty good info on high revving NA's if you need more, or search this forum,.. lotsa threads on it.
08-20-04, 01:08 AM
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PP is out of the question. I want it to be very driveable and reliable. I have a ACT prolite flywheel (something like 13.5lbs) and a TII transmission. I've noticed my car stops making power at about 7500rpm. So if I beef up the drivetrain and get a good clutch along with a new fuel mangement system and reasonable port (half bridge?) Could the stock motor be tuned to handle these rpms?
08-20-04, 01:53 AM
#6
Rotary Freak
Originally Posted by flamin-roids
PP is out of the question. I want it to be very driveable and reliable. I have a ACT prolite flywheel (something like 13.5lbs) and a TII transmission. I've noticed my car stops making power at about 7500rpm. So if I beef up the drivetrain and get a good clutch along with a new fuel mangement system and reasonable port (half bridge?) Could the stock motor be tuned to handle these rpms?
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08-20-04, 08:24 AM
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A bridgeport with all the above plus side clearanced rotors.
Pull the FI a go with a carb setup.
The driveline should be OK. Your torque won't go up that much - it stays flat while power goes up with revs.
Pull the FI a go with a carb setup.
The driveline should be OK. Your torque won't go up that much - it stays flat while power goes up with revs.
08-20-04, 08:32 AM
#10
Banned. I got OWNED!!!
Originally Posted by SureShot
A bridgeport with all the above plus side clearanced rotors.
Pull the FI a go with a carb setup.
The driveline should be OK. Your torque won't go up that much - it stays flat while power goes up with revs.
Pull the FI a go with a carb setup.
The driveline should be OK. Your torque won't go up that much - it stays flat while power goes up with revs.
08-20-04, 10:09 AM
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Originally Posted by 91mazdarx7
also what gear were you in when you took it to 9000 rpm how fast were you going did you just wot it until you hit 9000
08-20-04, 10:51 AM
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What does a scatter shield consist of? Do they make them universal or custom? Is it just some welded thick steel that wraps the top of the tranny tunnel?
08-20-04, 03:53 PM
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I know that most of the high reving 7 usually have apex seal modifications. Like they're made out of ceramic. The stocks engine's design might be able to accomodate revs to even 13000 with porting and exhaust work, BUT the other internal components like the stock seals won't.
There's also a way to port the rotor itself to give a deeper surface that effects it's weight and combustion volume. I think some 7's are modded this way when they're going to go above 10,000 regularly.
There's also a way to port the rotor itself to give a deeper surface that effects it's weight and combustion volume. I think some 7's are modded this way when they're going to go above 10,000 regularly.
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