RE: Shed Of The Week: Mazda RX-8

[RobDickinson]

Higher octane fuel made no difference in the 8, it did actually offset the cost of fuel compared to a 350z or subaru sti or whatever.

[otolith]

KuroKeeper said:

Just FYI, and this isn't specific to RX-8s, you will not see any difference in throttle response by running on higher octane fuel as it is calibrated to 95 RON - just like most European cars. Only in cars that are calibrated for higher octane fuel will you see a difference, and then it's more a case that you shouldn't be running regular fuel.

Off topic, but there are cars which are calibrated for super and state that as the minimum, and cars which are calibrated for super but state a lower minimum RON.

For example, our 350Z;



Vs our Saab 9-5 Aero



Back on topic, no point in putting super in the RX-8, which does reduce the fuel costs slightly.

[Fastdruid]

KuroKeeper said:

Fastdruid said:

I remember the salesman telling us we "could run it on super for better throttle response", I didn't dare, it was immediate enough as it was.

Just FYI, and this isn't specific to RX-8s, you will not see any difference in throttle response by running on higher octane fuel as it is calibrated to 95 RON - just like most European cars. Only in cars that are calibrated for higher octane fuel will you see a difference, and then it's more a case that you shouldn't be running regular fuel.

TBH I thought it was salesman boll*cks anyway, if it gave more power or better enough mpg it might have been worth it (allegedly my 2.5T has more power running on super, I can't tell, I do get a couple more mpg better, not enough to justify the cost though).

[ivorbigun]

I've rebuilt my own cheap RX8 - now I have a reliable car with 55k miles on the clock for similar money than what I sold my 155k mile, 1999 Impreza Turbo for. Only slightly worse economy, slightly more tax (older than 2006 is £280) - but ace driving position, RWD, not much difference in pace, and a lot more leather and toys. Already had a lot of fun on back roads. Can't wait to take it on a track day which is when I'm sure the impreza/rx8 battle will be decided.

It is a bit low on torque in the bottom half of the revs, but fortunatly it has gears which can be easily changed. Topping up oil isn't much of a chore or expense. MPG is the biggest issue, but just needs a dose of mtfu - and the money save on purchase price buys a lot of petrol!

For the price I'd totally do it again!

It was my first engine rebuild, and did take a lot of time, but I feel that warm sense of achievement of doing it myself (and warm felling from saving £1200 after parts and tools for doing it myself). Only special tools required were a 54mm socket (with suitably big impact gun or breaker bar), a homemade flywheel lock (bit of steel with four holes in it), and a dial guage to check end float. And obviously an engine hoist and stand. Loads of instructions on interwebs.

I'm in the lucky position of getting to use my engine hoist again (so soon!) to change my wife's RS Megane 175DCi gearbox - so it is a close call whether my french hot hatch or rx8 is the reliable car of the fleet - or even the 73 VW bus!

[Joeguard1990]

ivorbigun said:

I've rebuilt my own cheap RX8 - now I have a reliable car with 55k miles on the clock for similar money than what I sold my 155k mile, 1999 Impreza Turbo for. Only slightly worse economy, slightly more tax (older than 2006 is £280) - but ace driving position, RWD, not much difference in pace, and a lot more leather and toys. Already had a lot of fun on back roads. Can't wait to take it on a track day which is when I'm sure the impreza/rx8 battle will be decided.

It is a bit low on torque in the bottom half of the revs, but fortunatly it has gears which can be easily changed. Topping up oil isn't much of a chore or expense. MPG is the biggest issue, but just needs a dose of mtfu - and the money save on purchase price buys a lot of petrol!

For the price I'd totally do it again!

It was my first engine rebuild, and did take a lot of time, but I feel that warm sense of achievement of doing it myself (and warm felling from saving £1200 after parts and tools for doing it myself). Only special tools required were a 54mm socket (with suitably big impact gun or breaker bar), a homemade flywheel lock (bit of steel with four holes in it), and a dial guage to check end float. And obviously an engine hoist and stand. Loads of instructions on interwebs.

I'm in the lucky position of getting to use my engine hoist again (so soon!) to change my wife's RS Megane 175DCi gearbox - so it is a close call whether my french hot hatch or rx8 is the reliable car of the fleet - or even the 73 VW bus!

Excellent Work! Can you post a link to a guide if one exists?

[mikeyr]

At the risk of starting another RX8 war - why do they seem to have such a love of coil packs? Is it the design of the packs themselves or the strains placed on them by the engine?

[J4CKO]

otolith said:

KuroKeeper said:

Just FYI, and this isn't specific to RX-8s, you will not see any difference in throttle response by running on higher octane fuel as it is calibrated to 95 RON - just like most European cars. Only in cars that are calibrated for higher octane fuel will you see a difference, and then it's more a case that you shouldn't be running regular fuel.

Off topic, but there are cars which are calibrated for super and state that as the minimum, and cars which are calibrated for super but state a lower minimum RON.

For example, our 350Z;



Vs our Saab 9-5 Aero



Back on topic, no point in putting super in the RX-8, which does reduce the fuel costs slightly.

Though with the 350Z you brim it, do a handful of miles, then it does a massive burp and flings the flap open and shouts "BERK, FEEEEED MEEEEE".

[otolith]

J4CKO said:

Though with the 350Z you brim it, do a handful of miles, then it does a massive burp and flings the flap open and shouts "BERK, FEEEEED MEEEEE".

[ivorbigun]

Joeguard1990 said:

Excellent Work! Can you post a link to a guide if one exists?

http://www.rx8club.com/series-i-tech-garage-22/diy-rx8-engine-removal-how-w-pics-178937/

http://www.rx8club.com/series-i-tech-garage-22/com...

And there is a Mazda workshop manual for the actual engine rebuild

[KuroKeeper]

Fastdruid said:

TBH I thought it was salesman boll*cks anyway, if it gave more power or better enough mpg it might have been worth it (allegedly my 2.5T has more power running on super, I can't tell, I do get a couple more mpg better, not enough to justify the cost though).

You may well be getting more mpg on super but that is more likely to be a result of the additives in the fuel cleaning some components (mostly the inlet valves) than the octane. Most premium fuels are as much about the additives as they are the octane.

J4CKO said:

Off topic, but there are cars which are calibrated for super and state that as the minimum, and cars which are calibrated for super but state a lower minimum RON.

Very true!

...definitely got distracted. As you said, J4CKO, don't waste your money putting super into an RX-8. In addition to no octane benefit, there are no valves for the additives to clean so you won't see the same benefits as in a piston engine!

Edited by KuroKeeper on Tuesday 4th November 12:17

Edited by KuroKeeper on Tuesday 4th November 12:50

[otolith]

With NA engines it's a matter of retarding the timing. With turbocharged engines there is also the boost to control.

[KuroKeeper]

otolith said:

With NA engines it's a matter of retarding the timing. With turbocharged engines there is also the boost to control.

Absolutely right - sentence removed. I was just living in NA land for some reason.

[yellowstreak]

I think it would be an interesting project to do a self rebuild on, but isn't the RX7 missing the all important tubo charger from the RX7? Would it be easy to turbo?

[TREMAiNE]

yellowstreak said:

I think it would be an interesting project to do a self rebuild on, but isn't the RX8 missing the all important tubo charger from the RX7? Would it be easy to turbo?

EFA

Erm, yes and no. Owners that do go down the forced induction route tend to opt for a Supercharger over a Turbo charger, as it gives you more low down grunt which the car is missing. Petit Racing made a great one but its not for sale anymore.

Taking the twin turbo's from the 7 and sticking them in the 8 would be awesome though.

[Gypsum Fantastic]

I bought an RX-8 R3 a few months back to replace an Evo IX FQ-340. Haven't regretted it for a moment. I love how unique the engine feels, and while it has its drawbacks relative to the torque and overall power compared top the Evo, you appreciate the car a lot more when you accept that everything is focused towards the handling. It is an absolute joy to drive on even a small stretch of twisty road. While the Evo threw you around with its diff, and you always felt like it was reacting to the situation, the RX8 is so finely balanced that the smooth power delivery and small, centrally positioned engine all makes sense. It's a triumph of a car, and it's a shame it seems to be so easily dismissed by a lot of car enthusiasts.

[masermartin]

KimJongHealthy said:

otolith said:

They are particularly uneconomical on short journeys. It's about the worst choice I could imagine for a two mile commute.

Anything other than walk is rather silly for a two mile commute..

All very well saying that, but in a similar scenario (mine) at a walking speed of 3mph that's an extra 60 minutes of my day I'd quite like to use for stuff other than walking to and from work.

[cib24]

Then buy a bike. Driving any car for two miles is retarded.

[masermartin]

Aside from being able to go places straight from work, disappear out at lunchtime to somewhere other than the local shops and generally get stuff done during the day, sure.

[J4CKO]

masermartin said:

Aside from being able to go places straight from work, disappear out at lunchtime to somewhere other than the local shops and generally get stuff done during the day, sure.

I just plan my week based on what I need to do and whether it needs a car.

[Warnie]

cib24 said:

Then buy a bike. Driving any car for two miles is retarded.

st! my wife's retarded? I knew it!

I've just told her and she says your a tt! She also added that you must be a great laugh to go out with (not sure weather she was being sarcastic though). Anyway like most full time working moms who also do the school run and probably 80% of the household chores (I'm a bit lazy) she hasn't the time to be a perfect human being like yourself and must be indeed, retarded.....!