Tuning with Wideband

[SHGWAG]

Ok so in the interest of keeping my costs down for getting the RX7 on the road, I have been contemplating road tuning it.

So I have one of these:

http://www.nzperformance.co.nz/store/in ... d_508.html

And I have a base knowledge of where my AFRs should be, and due to this being a run in tune I would run factory timing with low boost 6psi. One of my main concerns is that my ECU doesn't run Knock sensors, but based on: Normal timing + Low boost + running rich + no heavy load situations = should be alright. Your thoughts callers?

I'm not interested in the "Don't do it yourself" comments, I am after advice from people who have tuned before. (Looks at Vvega / maybe even that fred fella)

[barf]

just have a good coolant temp gauge and be prepared to shutdown and tow it home, trust the seat of your pants

we found that spark timing has a greater effect over temperature than adjustments in mixture, this was on a 6cyl 4-stroke tho

get any excessive heat out of the system first, and be smooth on the throttle

[SHGWAG]

The coolant temp gauge would be on the laptop - digital readout which is a bit more accurate than the factory dash gauge. And with factory ignition timing I cant see it having any problems, correct me if I am wrong.

[mjrstar]

I have done a bit of home tuning, suggest things should be fine (so long as you are not pulling massive rpm or high load) it's unlikely you can do any damage tweaking on such a low boost setting. Make sure you have the o2 sensor well powered for the heating, i'd say give it 5-10 min and possibly run it off a second battery.

Leave it heating whilst you have the car stopped to fiddle. Save your tune files as a new file then if the car gets worse revert back to the old file rather than re-doing the new file.

A good battery for the laptop,

make the fan capable of running with the engine off to dissipate extra heat.

Once you get a decent idle and the ability to free rev the engine, the cruise tuning and acceleration will come pretty easily. My starlet has the power tune done at the dyno but the cruise and cold start etc I all did myself.

Also my evo has had the a/f's tweaked via a road tune with a mate.

Take my info with a grain of salt as my experience has also only been on uppy downy engines not roundy roundy.

most of all keep it safe and have a bit of fun..

i might edit this post if i think of some other useful shit.

[kpr]

what ecu do you have?

first thing id do is back the timing off. then get afr correct. best to start rich then lean it out slowly. then you can wind some timing back into it. generally the afr wont change when you alter the timing. you really need some form of knock detection when you start putting the timing back in. listen for it through a detset or detcans is the best way, dont trust some flashing lights or a number the ecu comes up with.

you can really do much damage if you go about it right. too much timing is the biggest killer esp on rotarys. lean mix at full throttle/boost is all bad too obviously, but not as bad as too much advance.

dont need to leave the sensor heating. if its inovate stuff like in that link. once it does its warm up 20 sec or so, its good to go. will throw errors if anything wrong

[mjrstar]

He's got a G4 I think, as for the heat on the sensor, I didn't explain myself fully, nothing to do with the readings etc, the info I have tells me the sensors will last MUCH longer if the engine is run only when the sensor is hot.

I'm guessing shit sticks to or effects the sensors life in some other means.

Is there audible knock on rotas?

[kpr]

ah yeh. but also remember you should delay the turn on if your starting engine from cold. water(condensation) on a hot sensor all bad.

yeh will still hear knock thru a detset on rotor. same deal. actually easyer to hear, due to lack of valvetrain noise

[Testament]

take heed of the thing about the fan running on manual though!

because when running quite retarded timing to start with you end up putting out more heat than if the timing was more advanced + you are idling a bunch,putting about and generally fucking around and things get HOT

[SHGWAG]

I'm running a Microtech LT10S

I'm running exactly what's in that link to NZP

yes - can make the fans run whenever I want throught the laptop. (2 twelve inch fans on a 3inch thick 3 core radiator)

Have the cold start & Idling sorted.

So in summary, wind the timing back, get the AFRs sweet, then start winding a little timing back into it. And at all times watch the temperature gauge.

mjrstar: I wont be putting it under full load or max boost or ringing it out, engine has only been run up to temp once since it was built, so not keen to thrash it straight away.

Thanks for the advice guys!

[SHGWAG]

This is a chart for the AFRs on a stock 13B-REW (FD3S with the twin turbo set up).

I stumbled upon this this morning. Seems quite rich up in the boost / rev range compared to what I've been told by a few people at tuning workshops. I believe this to be because Mazda played it safe up in the rev range by dumping extra fuel in.

What are your guys opinions?

Keep in mind a rotary is supposed to have richer AFRs compared to a piston engine.

[eke_zetec_RWD]

will you be getting a cert?

cert has a requirment of afr's at idol, cruise and full throttle. and they are a bit too lean for most tuners liking.

so what ends up happening is two tunes, one to pass cert test and one for after its certed. look them up.

[SHGWAG]

I'm thinking of just whipping out the adjusties, putting the standard suspension back in & taking if for a Wof. Will see if I can talk my WOF guy into not noticing the turbo / BOV venting to atmosphere.

But yes will eventually get it certed.

Would not like some cert guy giving it full noise on run in.

[eke_zetec_RWD]

Test pass/fail parameters

2.6(9)

A low volume vehicle, when tested in accordance with 2.6(6), must, in order to achieve a ‘pass’, indicate an air-fuel ratio of:

(a) during the steady-speed test specified in 2.6(6)(a):

(i) in the case of a carbureted engine or mechanically fuel-injected engine, between 12.8:1 and 14.9:1; or

(ii) in the case of an electronically fuel-injected engine, between 13.8:1 and 14.9:1; or

(iii) in the case of a diesel-injected engine, no richer than 18.9:1;

and

( during the loaded-condition test specified in 2.6(6)(:

(i) in the case of a carbureted engine or mechanically-injected engine, between 12.0:1 and 14.9:1; or

(ii) in the case of an electronically fuel-injected engine, between 12.2:1 and 14.9:1; or

(iii) in the case of a diesel-injected engine, no richer than 13.8:1;

and

© during the idle-condition test specified in 2.6(6)©:

(i) in the case of a carbureted engine or mechanically-injected engine, no richer than 12.8:1; or

© Low Volume Vehicle Technical Association (Inc.) 1 May 2008

LVVTA Low Volume Vehicle Standard Standard 90-10(00) (Exhaust Gas Emissions) Page 14 of 17

(ii) in the case of an electronically fuel-injected engine, between 13.3:1 and 15.5:1.

[SHGWAG]

So the answer to that is to wind the timing back, lean the fuel & hope like hell it doesn't go bang.

[kpr]

you'l get away with those afr's on your low boost of 6psi. you'd want to get it down as close to that 12.2 as you can tho. and the ones required at low load cruise. will be fine to run all the time.

yeh take some timing out. but dont go too far as you'l be burning half the fuel in the exhaust manifold.

whats the tune on the ecu at the moment? a rotary base map? someone elses tune? or starting from scratch?

[drftnmaz]

and set you rev limit to 5000rpm

[kpr]

/ leave actuator arm off turbo so no boost. / take spring out of external wastegate

[SHGWAG]

you'l get away with those afr's on your low boost of 6psi. you'd want to get it down as close to that 12.2 as you can tho. and the ones required at low load cruise. will be fine to run all the time.

yeh take some timing out. but dont go too far as you'l be burning half the fuel in the exhaust manifold.

whats the tune on the ecu at the moment? a rotary base map? someone elses tune? or starting from scratch?

Series 6 13b turbo microtech base map.

[SHGWAG]

and set you rev limit to 5000rpm

If i did that id have just over 3000rpm to drive it on.

[cletus]

when the certifier does the loaded- condition test it is supposed to be "moderate" acceleration from 70-100 kph, in the highest gear. so its not full load/big rpm like a power run on a dyno. i usually take the owner with me on a road test so they can see how the car is being driven.....