Mazda Rotary Club

Cars by Model Type => RX-8's => Topic started by: B.Martin on March 23, 2011, 10:07:38 AM

Title: Tuning an RX8?
Post by: B.Martin on March 23, 2011, 10:07:38 AM
I\'m sure I\'m getting annoying now, If I am just say please. I\'m just trying to gather as much information as possible before I purchase a car.

how does the FE respond to tuning i.e. Breathing mods, manifolds, de cat, full exhaust system, filters and induction (not forced) and does this push BHP up at all? Or is it mainly sound increase?

Can you get the FE upto 250bhp as a benchmark for my questions without spending big £££\'s? (ie not turbo/supercharging)

I\'m not going to aka about handout upgrades because all cars benefit from coilovers and big brake upgrades.

Is there anything I\'ve missed about RX8 performance tuning? I can\'t buy a car and not mess with it, jut not me!

Ben
Title: Tuning an RX8?
Post by: neil_jdmr on March 23, 2011, 01:56:57 PM
All NA cars struggle to improve on factory power figures with bolt-ons imo, I tried tuning honda b series engines for years and without chuckin a lot of money in then gains were minimal.

imo 250 genuine hp would be pricey
Title: Tuning an RX8?
Post by: dthebuk on March 23, 2011, 05:51:05 PM
FE\'s are fairly tuned from factory if you think about it. Before the renesis engine you\'d only see 230bhp on an N/A rotary if you had done some serious porting on it and spent a fair bit on fueling set up and tuning etc. Even then it\'d have naff all torque!

Brakes I don\'t think are needed unless you plan to track the car, they\'re pretty impressive in standard form.

By all means put a propper exhuast and stuff on it (wont be cheap) as it will sound nuts. specially when screaming along at 9.5k rpms.

Powerwise, you\'re better off stripping the thing out tbh
Title: Tuning an RX8?
Post by: B.Martin on March 23, 2011, 06:18:52 PM
Well DtheBuk after all these discussions I\'m coming tithe conclusion I\'m going to be better off with an FD. I\'d love to try going sideways and I love to mess about tuning and modifying. Just seemed that the FE would be the \'sensible\' option. What do you think?
Title: Tuning an RX8?
Post by: Arnie_O on March 23, 2011, 06:41:27 PM
your not going to see serious gains without FI in the FE i am afraid... though there are NA options out there to get gains once you have spend the cash... one remap option is the Cobb Access Port from Mazda Maniac in the USA, He has mapped thousands of cars all over the world.
though to get descent gains then you are going to have to spend to cash wherever you can. Breathing mods will help...
but the biggest way to get power out the Renny is FI. though its not cheap and unless you get it right then its not reliable from what i am told.
Title: Tuning an RX8?
Post by: dthebuk on March 23, 2011, 07:06:29 PM
If you can find a tidy fd, go for it! The only thing I\'d worry about is rats nest as they are hard to deal with if something goes wrong. Other than that, its pretty similar to the 8. Engine may die slightly quicker but thats about it!. If its got good compression and what not when you buy it theres no reason for it to die prematurely as long as you keep it serviced well.
Title: Tuning an RX8?
Post by: Will66 on March 23, 2011, 07:31:10 PM
The RX8 will cost a lot to make 250bhp from N/A.  Haywards have ported one and it is an improvement but I\'m not aware if they\'ve stuck it on a dyno to see what it makes yet.  F/I will net 300 bhp on the standard fuel system but you\'re looking at £5k to get it all set up and running.  

An aftermarket exhaust is practically essential for your RX8 but doesn\'t net you much power.

Intake kits can be tricky, the AEM/Mazdaspeed (it\'s the same kit) and the RB REVi are proven to be good.  Other kits can upset the airflow over the MAF resulting in poor idle and sometimes less power.  The AEM kit sounds awesome and the RB is quieter.
Title: Tuning an RX8?
Post by: B.Martin on March 23, 2011, 07:50:20 PM
Thanks a lot for all the info and opinions, you truly are all good forum members. I hope to find a nice rotary powered car soon and really appreciate all the advice I\'ve been given. Watch this space an I will keep
It updated!
Title: Tuning an RX8?
Post by: m1tch on March 27, 2011, 03:39:39 PM
Looks like even with a bolt on supercharger its only making 300 if you are lucky:

http://shop.pettitracing.com/pettit_racing/pettit_racing_supercharger_kit/g-62947.aspx
Title: Tuning an RX8?
Post by: B.Martin on March 30, 2011, 10:32:03 PM
Quote from: m1tch;751949Looks like even with a bolt on supercharger its only making 300 if you are lucky:

http://shop.pettitracing.com/pettit_racing/pettit_racing_supercharger_kit/g-62947.aspx

Surely for the price that is you may as well drop in a 13b no?
Title: Tuning an RX8?
Post by: Will66 on March 30, 2011, 10:55:59 PM
You\'ll spend as much again getting it set up and working.  

300hp at the wheels makes the RX8 quite a quick machine, California Style has a Pettit Racing Supercharger on his and it\'s a rapid machine.  But it\'s a lot of money and if you want big power you\'d be better off elsewhere.

Actually the Pettit Racing install is quite impressive, it\'s very smooth and linear.  It really compliments the car.
Title: Tuning an RX8?
Post by: B.Martin on March 31, 2011, 10:16:14 AM
It\'s a fair point to be making, but if your spendIng money on a supercharger 9/10 people want \'big power\' I\'d had thought. But I\'m not in anyway disagreeing with your precious statement!
Title: Tuning an RX8?
Post by: dthebuk on March 31, 2011, 10:39:06 AM
you\'ve also gotta consider the cost of bringing a 13b up spec which isn\'t cheap.

The super chargers looks like a great option imo. You get to keep the characteristics of the high revving N/A rotary but with more torque and power. Down on paper it won\'t look that good, but i can imagine it\'d be lovely to drive. Would suck for fuel though!
Title: Tuning an RX8?
Post by: Will66 on March 31, 2011, 12:58:20 PM
It\'s not much worse than stock according to California Style.  Tony\'s got one on his RX8, and with his HKS ECU he\'s got 32 mpg out of it, that\'s unheard of for a stock RX8!
Title: Tuning an RX8?
Post by: B.Martin on March 31, 2011, 01:55:40 PM
Quote from: Will66;752868It\'s not much worse than stock according to California Style.  Tony\'s got one on his RX8, and with his HKS ECU he\'s got 32 mpg out of it, that\'s unheard of for a stock RX8!

Awesome - more power better economy!
Title: Tuning an RX8?
Post by: dthebuk on March 31, 2011, 02:06:44 PM
Quote from: Will66;752868It\'s not much worse than stock according to California Style.  Tony\'s got one on his RX8, and with his HKS ECU he\'s got 32 mpg out of it, that\'s unheard of for a stock RX8!

damn! I stand corrected.

I was always under the impression that SC\'s were rubbish with fuel.

Actually come to think about it, they\'re a great idea, lol

would be interesting to see how the turbo\'s fair also as rotaries look to be making a comeback in the hybrid world
Title: Tuning an RX8?
Post by: B.Martin on April 04, 2011, 03:44:26 PM
Was driving through Limassol today and a black RX8 pulled out behind me, must have had a full system and decat exhaust because it was loud as f***, best description of sound would be to liken it to a motorbike. So much so that my mate I was with (without seeing it) commented that he hated loud motorbikes! I responded "it\'s an RX8 mate, sounds awesome!"

Slightly off topic, but great the share non the less!
Title: Tuning an RX8?
Post by: m1tch on April 05, 2011, 09:47:55 PM
Quote from: dthebuk;752888damn! I stand corrected.

I was always under the impression that SC\'s were rubbish with fuel.

Actually come to think about it, they\'re a great idea, lol

would be interesting to see how the turbo\'s fair also as rotaries look to be making a comeback in the hybrid world

I have found that if you get a slightly more powerful car or indeed more power at lower revs it will increase fuel economy as you don\'t have to rev it as much to accelerate. My daily drive is a Pug 306 Dturbo - turbocharged 1.9 litre, it does better mpg than the straight non turbo 1.9 as the powerband is further down the rev range, so a supercharger will give more torque and power low down, so should give a better economy than if it was just NA, plus the tuning can be done to get the fueling spot on for that engine, rather than a generic map on the OEM ECU.
Title: Tuning an RX8?
Post by: dthebuk on April 06, 2011, 09:55:27 AM
Yea well it\'s all about driving the car where it produces maximum torque in the rev range as you\'ll need the least amount of fuel to create said torque. What I assumed to be the problem with an sc is that it\'s more resistive than a turbo charger which would inhibit fuel efficiency. It should give you better efficiency at most revs but at the sweet spot the turbo should come out on top. Realistically though it\'s going to be an effort to keep the revs in the right place so maybe an sc is good.
Title: Tuning an RX8?
Post by: Will66 on April 06, 2011, 11:27:32 AM
The supercharger is producing more torque per rev than stock throughout the rev range.  I think the economy comes from getting the same performance for less rpm than stock so you\'re in a higher gear.  However in Tony\'s (Tango Tony, T200CAD or Exiled Viking, whichever he is on here, I can\'t remember) I reckon the economy is improved by his ECU being precise with the fuelling.  The normal pettit conversion uses a re-mapped stock ECU.