rx7_dren

Ok I’m not sure if this topic has already been written; just want to bring it up again,



ok this is just my theory,



RE problems,



Bad gas mileage

Burns oil

Low in power





So i figured fix the problem b4 upgrading the engine and maybe you ill be happy with it

These are all est. HP numbers; let me know what u think of if you got the same, if you did it b4

12A

105hp- stock 12A engine (4.5 psi)

5hp- remove fan

10hp- alt and main pulley changed

5hp- performance air filter

10hp- better exhaust

20hp- lighten rotors, e shaft and lap side housing

5hp- lighter seals and higher power ignition



160hp est. with the same psi, add a lighter flywheel and better clutch and this will be a excellent 12A or 13B

now I was told don’t lighten the 12A rotors because you will never hit high rpm with it or only to be used at track, but who says that’s how I’m going to drive on the streets, when I want more rpm I want to know its there, the point of this engine is to eliminate the problems and get some more power, now If I have 55 more HP I don’t have to step on the gas so hard, (less burning gas, less oil burn and more power) again this is just a theory “my theory”



anymore to add?

psyclo

milage - comparedf to what?

burns oil - not a rpoblem if you change your opil every 3k

low power - of course its NA

fan - <1hp there buddy

pullies - <5hp, their man purpose is to slow the water pump so it not damaged with consitant high RPM use

rotors - lighting the rotors and e-shaft will not net you more power, it will just rev margianly quicker and possibly rev higher

lighter seals - ??? I dont even know how think this would help

high power ignition - 5hp may be faciful on a NA engine but it will give you better gas milage



you can increase the potential redline by lighting the rotors and e-shaft but it would be much less expensive to just create more power in other areas, not to mention the stock intake manifolds are the bigger restriciton at that kinda of RPM. When you add hp you are not adding hp on the entire rpm range. because you ahve 55 more peak hp does not mean you will have 55 more hp while doing city driving.

rx7_dren

so ur telling me its a waste of time? im not looking for power.........most of these power is what i got of reading sites, 1 site clamed 22hp using the renisis rotors in a 13B, and another says 5hp for an eshaft, some says 10hp for main and alt pully, on top of all that i wanted to put an electrict water pump wouldent that help?

mazdaspeed7

Noone has seen any consistent gains from renesis rotors in a 13b to my knowledge. And lightening everything doesnt make hp, it makes the engien rev faster.



All your hp estimates are grossly inflated.

banzaitoyota

Simple answer to a complicated issue: HP GAINS ARE NOT ADDITIVE!



Every time you optimize one component, it is a dominoe effect to keep going to reap the benefits of the previous mod.

Feds

Actually, lightening rotors, etc does add power. Less of the force of combustion goes to accelerating the rotating assembly, and therefore more of it goes to accelerating the wheels.



You're on the right track Dren. The way to make an engine more efficient (therefore use less gas) is to optimize the engine's components, and the vehicle as a system.



The major killer to RX fuel efficiency is the low compression and the peripheral exhaust port. If you could find high compression 12a rotors, that would help your mileage a tonne. If you lighten the rest of the car up, improve the aerodynamics, put on low rolling resistance tires, it would help too.

banzaitoyota

Lighten Rotors and balance =$1200 (conservative)





90%(my number) of Rotary owners cringe and go into shock when confronted with the cost of overhaul software and hardware, let alone an additional $1200 for L&B

mazdaspeed7

[quote name='Feds' date='Apr 20 2005, 04:43 PM']Actually, lightening rotors, etc does add power. Less of the force of combustion goes to accelerating the rotating assembly, and therefore more of it goes to accelerating the wheels.



You're on the right track Dren. The way to make an engine more efficient (therefore use less gas) is to optimize the engine's components, and the vehicle as a system.



The major killer to RX fuel efficiency is the low compression and the peripheral exhaust port. If you could find high compression 12a rotors, that would help your mileage a tonne. If you lighten the rest of the car up, improve the aerodynamics, put on low rolling resistance tires, it would help too.


[/quote]





Raising the compression compromises the combustion chamber shape even more that the already poor shape it is at the stock compression ratios. Gains from the higher compression are likely to be offset by the less efficient combustion.



Why do you think the renesis stuck to a 10:1 in a world of 11.5:1 high performance motors?



And I agree that ligntening parts makes power in theory, but in reality, its not going to be measurable unless you do a significant change. You would notice it in lower gears, but in the form of the engine revving faster, not more peak hp. The gains from light flywheels are rarely more than a couple of hp at the wheels. You could easily have that much variance from slightly different barometric conditions.



If you want a noticable effect from lightening things, taking half a pound off the rotors isnt goign to do **** compared to taking a few lbs off the wheels, which also have a much much higher moment of inertia because of the significantly larger diameter diameter.







To rx7dren: youre focusing in so closely on the minute details youre missing the bigger picture. The major inefficiencies of the stock system are all in the peripherals of the engine. The block really is not bad at all from an efficiency standpoint, and the improvements that can realisticaly be made are minimal.

89 Rag

The money to balance is well spent, imo, and I agree, only a collective effort with all the worthwhile mods will allow you to reap the benifits. It would seem that ppl do three or four mods and think of the hp gains as compounding interest.

Dramon_Killer

spend like 3 grand to get a little bit better mileage?



I dont get it.