Leaded or unleaded?

[volvodspec]

earthing that middle pin makes the ignition 3degrees later throughout the whole map.
on models with a "katalysator" (catalyst i suppose?) C-6 and C-7 are earthed to make the ignition 6 degrees later.
C-8 is never used on a volvo 300 and is normally used as in/output for the knock-sensor.

therefore i don't think that your story about the renix with 2 curves just for the type of fuel is correct.

[shimon340]

but earthing the middle pin gives a different control map for 95 octane. No earthing means you have a more advanced timing map which is suitable for 98.

Earthing the pin on the B plug (only for later Renix units) is volvo's conversion for unleaded.

It may not be the case for all Renix units though... It is for all the B14 4Es that I've worked on that were 1985 onwards...

curious that the catalyst vehicles should have a different map. I wonder why that is.

[shimon340]

Hi there

Seems then the Renix has even more capability than the two maps above. Initial info shows that the extra retarded ignition in the catalyser models is probably due to the fact a more retarded ignition decreases NOx and HC. Need to check affect on CO as well. As far as I'm aware the catalyser models are tuned for the same CO as the B14 4E but of course are measured ahead of the oxidising catalyst. The retarded ignition would affect CO levels if it also affects HC and NOx. The catalysers were a voluntry thing by volvo not required by any legislation. Just them being 'nicer' to the environment. I wonder what the affect was on fuel consumption.....

Indeed, the knock sensor function is used on the 400 series who have an ability to adjust themselves to varying octane levels in fuel. This system was also used on the 850. Does the 900 series have such an ability? I guess on later models as he 850 could do this from 1994 operating down to 91 octane.

[shimon340]

PS where did you get the info on the catalyser models have a further 3 degree retarding ignition map from??

[shimon340]

ok...bit of digging via SAE and various other university papers and research publications.....retarded spark reduces NOx and HC and has little effect on CO except when very retarded the CO will increase. These are rules of thumb though of course.

This extra retarded map for the catalyser cars makes sense given the voluntary "green" environmentally kind background to launching these vehicles. I think they were the EEVs (environmentally enhanced vehicles) of their day. EEVs (diesel) offer better than Euro 5 emissions require and therefore customer get a tax discount or grant of some sort.

Also explains why the B172 with catalyser (oxidising cat only) has a different map, presumably also more retarded.

So overall, the catalyser models have modified map to give lower HC, oxidising catalyst to give lower HC and CO and modified map to give lower NOx.

Very interesting and they pre-dated Euro 1 and mandatory catalytic converters.......

[shimon340]

http://www.sae.org/technical/papers/840447 and others maybe of interest to people

[shimon340]

From Mac's article on the Renix

"However - one tip - If you run an 84,85,or 86 year car with a Type 402 Renix and suffer pinking on unleaded fuel you can retard the ignition timing by 4 degrees by earthing terminal 7."

See http://volvoforumsrepairs.org.uk/300Rep ... 0renix.htm

Looks like the catalyser models only have an extra 2 degrees of retardation then based on your 6 degree info above.

[volvodspec]

how i know?

i have a '89 340 K9 (dutch enviromental code, don't know if that's international)
it stands for equipped with catalyst, engine is an original B14.4E.

all v340 renix models have a operational C-plug though, even the few renix equipped B14.3E's have a working c-plug.

info about 6 degrees later with c6+c7 earthed and 3 degrees later with c6 or c7 earthed comes from the technical documentation of renix i have.

all late model b14's (b14.3 and on) are able to run on unleaded RON91 without problems, other than that you can put unleaded 95, 98 or even the real german v-power octane 100 without the need of adjusting the renix ignition curve. if there was a problem with those types of fuel, the exhaust test at mot would instantly notice wrong levels of CO etc.

[shimon340]

hi there

Here's a link to Mac's article

http://volvoforumsrepairs.org.uk/300Rep ... 0renix.htm

Indeed as you say terminal C is the one with pins 6,7 and 8. Given that the 402 was fitted to the B14 3E and the 4E, one can run 3E's on 95 octane by earthing pin 7 and retarding the map by 4 degrees. From your info, pin 6 being earthed is the same as pin 7 being earthed. Volvo only said pin 7 but you've got some Renix data too!

Earthing pins 6 an 7 gives you the map for the catalyser models. Interesting....

Would you be willing to email me a scan of the Renix info you have? Is it in Dutch though?

Interesting that B14 3E and 4E can run down to RON 91.... If the 3 degrees retarded map can cope with 91 octane then it can cope with anything higher therefore ok upto 100 octane as you say. The problem is when you have the advanced map (or the '98' map as I referred to it above ie with no earthing to pin 7) and try to run on 95....then you get pinking. As above, if you run a retarded map you can go up in octane of the fuel ie a 95 map can run 98, 100 etc. Problems are when you take a map advanced for 98 octane and then go down to 95, then you get pinking. Exact affect on emissions would be worth looking into though on a 95 octane map and running higher octane. I've got a friend who's a petroleoum additive researcher who would know the answer to this.....

Pinking, knock and detonation are all different but get lost in translation and also American's use different terminology making even reseach papers confused.

With regards CO levels with a retarded map (as per your example of running down to 91 octane on the 3 degrees retarded map) I believe that within limits (general rule of thumb and every engine is different) the CO wont be affected unless the timing is so far retarded that the CO rises due to too short combustion time. Also, if too far retarded the flame front exits out the exhaust valve overheating it rather than just hot gas. I wasnt able to find today a more detailed thesis or paper on CO and ignition retardation but did find quite a lot on HC reduction with retarded ignition. Still a recent topic as this paper was from GM's labs in the USA and was from 2005. They were looking at HC reduction and the mechanism of it but didnt mention a detrimental affect on CO. One might expect a mechanism which allows for more oxidation of HC would also reduce CO. But, in the world of chemical kinetics things arent always so clear. Petrol is varying from season to season and oil field to oil field even though the resulting blended mixture behaves within certain tests to be called "RON 95 unleaded". In terms of chemical kinetics petrol and diesel are a bit of a nightmare given the 1000s of components and the variabilty of the fuel itself. Engineers will specify retarding ignition as not affecting CO but really from a chemist's point of view changing fuel sample will really affect CO given the different reaction pathways which occur with differently composed fuels.

anyway....thanks for the Renix info!

[shimon340]

hi again,

as you're in Holland dya have any info on the factory fitted 340s that ran on LPG? If they were B14 3Es and onwards I'm thinking the Renix has "built in" LPG map. LPG needs ignition retardation and I'm wondering if the 6 degree map was what volvo used for the LPG cars.....it just so happened the same map was also used for the catalyser models to lower HC and NOx.

[volvodspec]

6+7 are originally grounded on my red car; this should retard the ignition by 6 degrees. could be that one pin makes 4 degrees retarding instead of the 3 i thought of

reading trough mac's info:

B14.4E = 412 (1987ish on) Retarded by 4 deg. to run on unleaded.

i think he is wrong with able to run on unleaded, i believe 412 units are used on b14.4e engines with a catalyser wich i can check tomorrow on my own car so don't make what i've just said a fact, i could be wrong just as easy too

interesting article though, i learned about renix the hard way... very good to see that basic testing is well documented. as for info, i can't scan the info in my head or do you have a solution to that ?

very funny mac mentions the insolation material on the back of the renix, i fucked up a unit a while ago trying to remove the stuff:D tried heating, chemicals and my bare hands but none of them worked

i don't think that you can call it a special map when grounding C6, C7 or both, that way you can switch the wires on the TDC sensor and call that 3 degrees advance a special map too...

i could check in my documentation about the factory equipped lpg models, but i'm afraid that's gonna be a big search.. will try to look it up though:)

[shimon340]

hi there

The LPG info would be great if you can find it!

I'll try to check a B14 4E with catalyser and a B14 4E from 1986 (no cat) as well to see which units are in each. Indeed, the catalyser has extra wiring on the pins 6 and 7.

What's the flywheel sensor mod you refer to?

Overall is still seems te Renix has more than one map in its memory for the 402 then....

[shimon340]

potentially but subject to us both checking some more maybe then the 402 has map A and then by earthing pin 7 you get a 4 degrees retarded map. (4 degrees retarded is good for 95 octane. Map A is the original 98 octane map).

From 1987 onwards the B14 4E gets the 412 controller, with 4 degrees retarded map from original map A).

If catalyser models use 412 with pins 6 and 7 earthed, one gets 6 degrees retarded map from original map A.

all interesting stuff,

nice discussing it with you!

[Chris_C]

I'll try to check a B14 4E with catalyser and a B14 4E from 1986 (no cat) as well to see which units are in each. Indeed, the catalyser has extra wiring on the pins 6 and 7.

I'm pretty certain mine had no extra wiring, just the standard 2 plugs.

[volvodspec]

well seems i was right;

my '89 340 with catalyser has the b14.4e engine and the renix 412 unit!

so in that way, the info in mac's article isn't correct it's not because it's for running on unleaded but because it has to be retarded to minimise emissions adding up to the catalyser ; all b14.4 can even run on garbage petrol ron 91 unleaded!! i allways fill mine up with unleaded ron 95, good enough for the b14 if you have a completely healthy engine.

my '86 340 with b14.4e and no catalyser originally had a 402 unit, and no c-plug present. things have changed now