Pinball

Ive been considering getting a RX-8 for a while but the lack of mods to produce more power/torque without adding f/i kinda turns me off to it. Im not talking a major increase just somethin that will show gains of 15-20 ft-lbs of torque. The problems with computer tuning is that it will void the warranty. So i was thinking, rotaries run very hot so wouldnt it help to produce more power if you could cool it down? Bigger radiator and better oil cooler are what i was thinking, maybe even a hood with functional vents. Just cooling the engine bay alone would make intake temps slightly cooler. Is it possible to say that a full exhaust (header back), light weight flywheel and upgraded air filter could see gains of 15-20 ft-lbs on the dyno?

thanks in advance.....

dmp

Couple of things:

Flywheels don't make HP - any gains they offer would be un-measurable, or so tiny as not not make a difference on a dyno pull in 4th or 5th gear. 3rd gear? maybe a couple HP difference...perhaps.

Computer tuning voids warranties? How? Unplug it, and take it out before you take the car to the dealer.

Intake(not just the filter)/Header/Exhaust + Canzoomer = 20-40hp increase.

What ppl don't understand, or won't understand is, ANY 1.3L engine won't have HUGE gains w/ bolt ons.

Headers for a 5.7l Chev engine? 40hp.
Header for 1.6L Miata engine? 5hp.

Fanman

I have not heard of any viable headers for this car yet. There are a few outt here but they are ridiculously expensive and have been dyno proven to show little gain. Even with the air intake, exhaust & Canzzomer unit you are looking at probably closer to the 20 than 40 side of the hp gain, and the tq. gains have been minimal. A few posters have dynoed with this coombination and have gotten about 18 to 22 whp but the tq gain was around 4-5 lb.-ft.

Pinball

you guys are kinda gettin off the topic i was trying to hit. Basically im trying to find out if upgrading the cooling system could show considerable or measureable gains. I've done my research, i know that these engines dont gain much from bolt-ons. I also know these engines run very hot, so i would think that cooling them down would show some good gains.....

thoughts?

socalightning

I'm thinking you might not ADD horsepower by increasing the cooling capacity. If anything, I think when the engine compartment gets hot and thus the intake heats up and air temp increases, our cars may lose some HP (heatsoak perhaps ), so counteracting the engine compartment heat build-up may prevent the loss of HP. I'm no powertrain engineer though. :o

I for one, would love to have some hood vents and also find a way to isolate the air cleaner box and tubing from heat a little better.

A lighter flywheel will feel like you have more power, even if it doesn't add power - it's a good mod.

As far as increasing torque with new exhaust, I've read somewhere that if you increase the speed or velocity of the exhaust stream that it should give you more torque - maybe smoother bends (as in a header) could do this. ...And that some people increase the diameter of the tubing (maybe too much) and slow the actual velocity of exhaust gas and this can reduce torque down low and maybe increase up high - guess it has to be tuned like everything else on the 8. :p

Pinball

Basically, im trying to think of a new way to free up some power. Im sure u guys have heard of intake spacers, could those be made for the 8? They do a very good job of cooling the intake manifold. If you were to use those with some air vents, and better oil cooler the entire engine bay temps along with your entire engine and intake temps could drop considerably. resulting in a increase in power. Not to mention the fact that if you were to buy a hood with vents chances are it would be made of a lighter material too.

The reason i thought of this is because i dont want to risk reliability by installing f/i. Infact lower engine temps could in the long run increase reliability......

opinions?

Relentless

The answer is no. You're not going to actually gain 20hp by cooling.

The flywheel, however, will improve throttle response and driving feel such that it will gain 10-20 hp in drivability, but your car won't actually be making more hp. I have a big radiator, too, and that's working out fine. Better cooling can't hurt, but you're probably going to need some kind of engine management if you're looking for that kind of power.

shelleys_man_06

Right. You cannot create more power from simply cooling the engine. There is very little to gain in thermal efficiency, even with a high-flow, high-capacity radiator. I'm sure you must've had the idea from the fact that cooler air has the ability to create more power, since the charge is dense. This is especially more important with forced induction.

Sputnik

I agree. There is a point where if your engine gets too hot, then it will lose power. But as long as your within the engine's operating temperatures, there is nothing to be gained by adding more radiator or oil cooling capacity. If you find yourself on a racetrack (not a dragstrip, your car really doesn't have enough time to overheat on a dragstrip unless something is wrong), and the coolant or oil temperatures do get too high, then you need to do something about it. But if your engine runs fine as it is, upgrading your cooling system won't do anything. First, engines need to be up at a certain amount of temperature to work well. Second, once the coolant gets down to a certain temperature, the thermostat will simply bypass the radiator anyway.

---jps

Shamblerock

I agree with Sputnik. Also in Toronto Canada, its below freezing every day. It take my car more than 10 minutes to hit operating temperature (near the middle of the dial) whereas a v6 would take half that time max. So it seems to me that the heat produced from the engine is marginally greater than the outside temperature. Put the heater on full blast at idle and the temp will go down below operating temperature. As this would seem to be the best case scenario for cooling the engine and consuming cold air intake, I personally haven't noticed and increase in power whatsoever compared to a hot summer day.