twilightprotege
Member
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- 2001 323 Astina SP20 (P5)
yes.
NA Tech Race to 100whp per 1000cc's
- Thread starter LordWorm
- Start date
twilightprotege
Member
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- 2001 323 Astina SP20 (P5)
the kl - if the valve train can handle it (which is cant), there's no reason why a KL cant go to 10000 easily
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
Also the oiling system is trash.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
So a question, When looking for longer rods obviously something will have to be modified so each will work with piston and crankshaft.
What is OK if a candidate is found, does it matter. I'm new to this kinda stuff.
1. Rod has smaller wrist pin and crank bores so it can be bored to a larger diameter to accommodate stock crank bearings and wrist pin sizes.
2. Rods has larger crank bore and make larger OD and same size ID bearing.
3. Rod has larger wrist pin bore and make bore in Piston match rod.
4. Both 2 and 3
What is OK if a candidate is found, does it matter. I'm new to this kinda stuff.
1. Rod has smaller wrist pin and crank bores so it can be bored to a larger diameter to accommodate stock crank bearings and wrist pin sizes.
2. Rods has larger crank bore and make larger OD and same size ID bearing.
3. Rod has larger wrist pin bore and make bore in Piston match rod.
4. Both 2 and 3
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You don't need to modify the crank
You find a rod with the right big end and small end width, and you're set. Custom pistons are then used to deal with the bigger wrist pins (bigger wrist pins are not a bad thing by the way...but too big and you'll limit how far you can push the centre of the wrist pin up, which needs to be done otherwise the piston is going to fly out the top of the deck)
on the subject of fuel burn - work out max piston speed (which is a function of stroke) - then work out how fast the flame front of regular unleaded fuel travels at. If piston speed within 30 degrees after top dead centre is faster than the speed of the flame front, then you need to find yourself some better fuel
that 30 degrees of crank rotation after the combustion event appears to be the time when most if not all of the force of the combustion is exerted on the piston. From memory the burn speed of regular unleaded fuel is somewhere around 4000 to 4400 feet per second (but i'm just pulling that number from my memory, which is a bit flakey of late!)
So....in summary - some limitations on getting an engine to rev, and how to get around those limitations:
limitation 1: piston acceleration
this is what will make your engine "fly apart" and why twiggy and I bang on about how a stock length rod that is proven to hold 500hp at 7000rpm is not necessarilly up to the task of holding 200hp at 9000rpm. Given that the force exerted on the wrist pin, block and rod are going to be a function of acceleration, mass, and angularity, the faster you spin the engine, which will increase the piston acceleration, the more force you will apply to the rotating assembly and the block.
You get around this problem by improving your rod ratio
limitation 2: mass
as above, mass is part of that force applied problem - you can get more revs by dropping the mass of the rotating assembly - acceleration will remain high, but force will be lowered because mass drops.
You get around this problem by using light weight, strong rods (probably made out of exotic materials, such as titanium, or aluminium)
limitation 3: rod angularity
You get around this problem by improving your rod ratio
limitation 4: piston speed/fuel
you can drop piston speed by dropping your stroke. if you can't drop your stroke, you may have to use some sort of jungle juice fuel (either race gas, or methanol, or some sort of additive that improves burn speed)
limitation 5: head and manifold flow
theres no point in building an engine that is mechanically capable of revving its balls off if you can't get enough air and fuel in, and exhaust gas out. When i was quoted on my engine build, over 70% of the price was going to be head work and manifolds. I was striving for 9200rpm in full race trim, so the head work was quoted based on that goal. Getting the FS head to flow the way it needs to will be a mission.
at high RPM coupled with high compression you also run into ignition problems so some sort of suitably beefcake ignition system is going to be par for the course.
my advice is to bore the engine as far as you can go, drop the stroke as far as budget allows (FPDE crankshaft with custom rods and pistons should do the trick), then work out what kind of RPM is required to achieve reasonable VE for the power goal, and then start working out what needs to be done to the engine to get it to support that kind of RPM.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
ok I understand about the wrist pins but what about thicker crank bearing. Such as bearings with the stock the ID but larger ODs to fit a larger bore rod.
Just on a side note. I love this s***.
Just on a side note. I love this s***.
but if one wanted to get more torque... wouldnt you have to get a bigger crank if u can? i noticed with Mazda, not trying to diss them, their older motors seems to be more workable than the FSDE... maybe because the FSDE wasnt meant to be an all out race motor unlike the KL and the Rotaries could be...
for a mid-range torque power gain, the lighter pistons and stronger rod would be really still be effective, right? and would monster cams still be drivable in the street? what makes it a monster cam? just bigger lobes? just trying to gather my information before going to a shop... what material would you suggest for the Pistons?
for a mid-range torque power gain, the lighter pistons and stronger rod would be really still be effective, right? and would monster cams still be drivable in the street? what makes it a monster cam? just bigger lobes? just trying to gather my information before going to a shop... what material would you suggest for the Pistons?
ok for starters, the KL isn't meant to be an all out race motors.... hell toyota's 2JZ isn't meant to be a race motor. Some engines are more adaptable than others - designed for higher end street performance/sports car applications. The KLZE, and BPT etc fall into these brackets, but they are not without their own problems.
The FSDE is more or less an economy engine - why they slapped it into the P5 when they could have used the FE-DOHC (which is a far better 2L engine, probably the best 2L 4cyl engine mazda ever developed) we will never know.
Now torque....why is everyone so hung up on masses of low end/mid range torque? the FASTEST circuit cars in the world are high RPM, top end power monsters. if you do the maths, you will find that the LATER your torque curve occurs (that is, the less "low end" you've got in relation to top end), the faster you will accelerate, due to gearing.
To boot, engine torque is only a small part of the equation - gearing is what matters. Higher RPM = better gearing advantage for any given gear. Also the thing that makes your wheels spin is ROAD FORCE - that is engine torque multiplied by total gearing. Without touching the engine, you can increase the amount of effective force at the wheels by simply changing the rotating diameter of your wheels (with smaller rims, and smaller tires).
NA builds on small capacity atmo 4 bangers is always ALWAYS going to be a question of compromise. they do not build masses of torque like large 6 cyl and 8 cyl engines, so all you can really do is make them spin faster, build more top end power, and use the gearbox for what it was designed to do.
Going to a bigger stroke will SLIGHTLY increase the pumping capacity of the engine (nowhere near like what increasing bore will do), but the trade off is going to be a lack of RPM to take full advantage of it. The best performance motors in the world are either "square" (that is, bore and stroke are equal), or "over square" (that is, bore exceeds stroke). Our motors are badly "under square", and stroking the engine further is only going to make matters worse. Your already sh!t rod ratio becomes even more sh!t, your piston speeds and piston acceleration goes through the roof, and you'd be lucky to spin the thing to stock redline let alone anything further.
Sure, a bigger stroke will mean you'll be able to ingest more fuel and air at lower RPM when compared to the stock stroke, but you'll brick wall at around 6000 to 6500 rpm because the rods just wont be able to take the abuse. Now, for a turbo build where 6500rpm is probably all you are going to need, a stroker kit would probably be something to consider - personally I still wouldn't do it, but its at least a legitimate mod on a FSDE that is boosted. For NA, stay well away.
It is totally false to think that a high revving, top end heavy NA motor will not have "lots" of torque - torque and power are related. Relative to power, the torque may not be as high, and the point in the rev range where the torque "comes on" might be higher - but because power and torque are related, you'll still make it.....and you'll make it in a more useful rev range for almost any form of motorsport you can imagine. Sure it might not be so nice for quiet sunday drives, or trips to pick up the shopping, but lets be honest - if you are out to build an Atmo rocket, its not going to be something you drive your mother/wife/sister to the shops in, is it?
Rods, and high comp pistons are still highly recommended for any "serious" NA build, regardless of where you are going with it - Rods because the additional strength, plus the extra rod length means you can get more revs out of the engine if you want to (as long as you meet all the other criteria i posted previously), and pistons because you can push your compression up - which in turn means you can run bigger cams with more overlap, with little or no ill effect.
What makes "monster" cams? well....a few things. Its not just "bigger lobes"...there are 4 things that come to mind:
1) Lift - how much the cam lobes physically open the valves
2) Duration - how many degrees the valves stay open
3) Ramp Rate - how fast the cams open and shut the valves
4) Overlap - how many degrees both the intake and exhaust valves are open simultaniously
Overlap plays a part in dynamic compression (which is why higher compression pistons allow for more overlap - the additional "loss" in compression due to overlap is counteracted by the fact that you are producing more compression to begin with).
Cams are essentially the "brains" of an engine. They control when, and by how much, the valves open. Playing with cams can have massive effects on drivability. Big monster cams sound cool, but can lead to a rough ride at low speed where the engine is essentially running in a state outside of where the cams are useful.
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yes, it would have been far better.
thanks...glad someone finds my drivel interestingi love ur posts lordworm. its very interesting and i learn something everyday
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
In all honesty I've learned more about our engine and engine building in general in this thread than any other place.
Plus all the research I've done because of this thread
Plus all the research I've done because of this thread
awesome!
Thats more the point than anything. I don't think anyone REALLY expects a whole crew of 200hp NA P5's rolling around as a result of this thread (though we might see a couple yet!), but my greatest hope was that it would stimulate discussion, get some of the myths dispelled, and get people thinking about some of the more exotic things you can do with an NA piston motor....
jimmysuite
Member
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- 2003 Mazda Protege5
I've line up a spare fsde for myself to experiment with. I feel the 200hp mark is possible without destroking the fsde (although it would still be very tough to be the winner of this competition with the constraint of 100whp/L)
The setup I am thinking about looks to be feasible based on LW engine calc spreadsheet and the fact that my car once tuned correctly (inc high rpm afrs and add timing) should be able to put down ~160whp (mustang dyno) all on heavy stock internals with crappy rod ratio, stock(ish) redline and low compression (relatively).
In all reality a 50% improvement over stock hp is huge with off the shelf parts, which were not designed to go together.
The setup I am thinking about looks to be feasible based on LW engine calc spreadsheet and the fact that my car once tuned correctly (inc high rpm afrs and add timing) should be able to put down ~160whp (mustang dyno) all on heavy stock internals with crappy rod ratio, stock(ish) redline and low compression (relatively).
In all reality a 50% improvement over stock hp is huge with off the shelf parts, which were not designed to go together.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
Do you want me to overnight a camera to you so I can hear your car.
jimmysuite
Member
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- 2003 Mazda Protege5
I actually took some video with a friend's camera but couldn't figure out how to upload it. I'll work on getting the instruction manual or find someone who has a DVR.
We took two drivebys and one inside the cockpit. Even with the stereo microphone on the camera the sound on the playback doesnt do the car justice. (it still sounds sweet though) I roughly guesstimate that the 0-60mph time is 7-8 seconds from the inside shot of the dash (really crappy launch at no extra charge
).
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
USB cable? plug that in,then usually the computer will recognize that a device has been hooked in.
then use photobucket or youtube to upload to interwebz
then use photobucket or youtube to upload to interwebz
jimmysuite
Member
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- 2003 Mazda Protege5
It's got a usb cable but the only thing the computer recognizes is the SD card (photos only) the video is still recorded on tape (small one but its still a tape)
unless im missing something....
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- 03.5 YLW MSP
Whats the make and model of the camera? I'll look up a manual for you and tell you how to pull the pics! However like stated earlier just plug it into the computer normally USB cable and goto "My Computer" and you will see that theirs an extra drive and thats the camera. Then just drag and drop to your desktop and upload it to the web usign youtube or something.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
Uggh. You would need a USB video capture cable. They are pricey and not really worth it just to put a video up. Basically you would plug in the A/V cable from the Video Recorder to this.
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- 02' Protege ES (Gone)
16' Mazda 6 sport manual
