Anthony Rodrigues

You guys are spot on with cylinder pressures and detonation. I mostly find that vehicleproblems with fuel supply and injector duty issues relating to lean running conditions apply in the very top end with customers cars. Inadequate intercooling issues also apply. It is probably more of a professional courtesy decision that we make, that the power returns given by the last 3-5 degrees of timing are relatively less than the reduction in reliability that they can result in.
I believe that the purist may add into the top end of an ignition map and I do on my race car, but I have made that decision for myself and am prepared to pay the consequences if required. I also use a complex alcohol enrichment which helps guard against detonation in the top end where I run extreme EGT's)
Earlier today I tuned a 13b Turbo at over 500rwhp and found a mere 8rwhp loss by lowering the total timing by 4 deg. Given this was an 8" tyre RX3, this ammount of power was never to be realised or noticed, so I left the timing out. I can assure you that the insurance level added into the combination was far greater than 1 or so % of total power.(the car went 9.6@148mph, big traction problems,toyota box, full street car) I hope you understand what I am saying.
Regards-Anthony

pluto

You advance the timing as much as you can until the motor blows, you rebuild the motor and back off the timing by 3 degrees should be sufficient!....

Seriously, I wouldn't mess with timing too much on pump gas. octane rating plays a major role in timing and a/f ratio. no matter how conservative your timing is or how rich your a/f is, if you have a bad tank of gas. Your motor will detonate. Generally, I wouldn't go anything higher than 17 degrees (max) on anything below 17psi of boost. So based on gordon's proposal, you can have a timing of 10 degrees at 4000rpm and increase it by 1 degree on every 500rpm......

Anthony Rodrigues

Pluto is the man.
There is a saying we have in Australia that you never get to hear a performance rotary detonate. It just stops BBBRRRRRRRRR. The more of them you tune the easier it is to find the point and pitch that tells you to stop. I know it is not what people want to hear but it is the truth. Thus adding more weight to listening to experienced tuners that know your set up.
Re gards-Anthony

j9fd3s

iTrader: (3)

ive noticed that when you set the mixtures (lower rpm) you know its right because it makes that sound. the factory uses pressure sensors installed in the housing to directly measure the "cylinder" pressure. they actually put several in, that way they can "see" the shape of the flame front.

mike

Anthony Rodrigues

Gordon,
Under 20psi boost I have used an amplifier that you attatch to the block and you can hear detonation earlier than normal (chassis ears), and you will usually see a lean scatter in the wideband. However, some time soon I will try to document dyno info I have on timing changes, timing changes seem to be a black art.
Re gards-Anthony

a777

Great thread everyone!

Out of interest, have any of you used a 5-gas analyser as well as a wideband while dyno tuning? You can gain some very useful information watching the 5 gas as well

There seems to be two schools of thought that I hear for tuning on C16, one which is quite conservative in timing, and the other which is fairly aggressive. Both having different Air Fuel Ratios...

Boostn7

>Generally, I wouldn't go anything higher than 17 degrees (max) on anything below 17psi of boost. <
Hi Pluto, so you don't run more timing at lower boost levels?

Based on my own experience there is not much gain in hp when adding timing after peak torque.......unless timing is low at peak torque.

Ported/big turbo rotaries make peak torque later and broader in the rpm.
On the street I leave the timing flat after peak torque(same load). On race gas I do add another 2-3 degrees after peak torque...feels like it revs faster:-)

Whever on the dyno(4th gear) I add timing 'till the engine is producing the most power while EGTs remain in a safe zone...if I add 1-2degrees more and only produce 1% or less then I back off the timing.
Reagarding trailing split:
Since I run the Wold3D my split is locked. On the dyno I tryed going from a 15degree split to a 10degrees split all around and notived a 6-8hp gain all around 'till it hit ~5.5krpm @ full boost(18psi) where it took 25+hp loss 'till 8krpm. I raised the split back up to 15 degrees and the hp was back again. Same thing happenned to my friends 13B-REW (62-1 turbo) also with the Wolf3D.
Anyone else noticed gains when adding split at higher boost levels??

On my 94 FD with PowerFC(base map) they run "0" split 'till it starts boosting where(I believe) goes up to 12 degree split at max boost....which I have been told those maps resemble the factory maps.

Ignition timing will vary a bit between porting and engine set-ups.....
I agree with GMonsen...as far as the greatest risk of too much timing to be from the point where you hit full boost to where the engine hits peak torque(most stress).

It's nice to see some experienced "rotary tuners" throw in some of their input such as Hitman, Anthony, Rice, Pluto and so on........threads like this make me take notes and give those notes a try on the dyno.

Hi Anthony...remember a white Turbo II(10th Ann Ed) which was on the dyno @ Mothers in NJ (near MVA's previous shop). We spoke quite a bit that day.
Same day I experimented with trailing split....car made 508rwh @ 23-24psi 'til the clutch let go in 4th !!!!!!
Do you remember?? Pleasure meeting you.

Later, and lets keep this thread alive.

SPOautos

WOW, I was out of town over the weekend and didnt expect to find much here.....BOY was I wrong!!!!!

This is a great thread, I'm taking notes so you guys just keep thinking out loud haha

This is a tremendous help to me!!!!!!

You guys should see the Power FC base map!!!! I'm going off memory but I believe it has around 21 degrees of timing at 8000rpms and around 12-14psi of boost. That sounds way to high to me, according to what I'm reading here.

I'm going to totally change my timing map, all this info is great guys!!!
STEPHEN

Maxthe7man

Looking at the anti lag timing, which seems to retard the hell out of the timing, would there be any benefit to holding the timing back till say 4 or 5 psi in order to help turbo spool, or is that just gonna pull the rug out from the motor, I was thinking that holding the timing back would create a little more heat in that range.
There seems to be so many schools of thought when it comes to pre-boost timing, I have seen maps with 8 degrees advance up to zero psi, then I have seen some with 35 degrees.. Any thoughts on this? Max

Marcel Burkett

Anyone have any info on timing ( maps and split ) for a half bridge ported motor running a T 66 and (soon to come ) a pair of MSD 6A ' s and a pair of blaster coils ( for lead plugs only ) ? , also what plugs should I use ? , I am also running water injection .

Kurgan

I'm going to be getting my 20B to run this weekend (with any luck) and I'll have to come up with a map. Right now, the map in it may work, but it will be a bit lean which is no problem to fix with my FJO. The problem I see is that I have no clue where to start the timing out. Gordon says to start out (in vacuum) at around 30 degrees, then creep it up from there. I want to be VERY conservative on my freshly built and ported 20B and was thinking of locking the timing at a certain degree, say 14 across the board. I know this will kill power almost throughout the entire power band, but this is just for break in... anyone have any better suggestions?

And yes, I will be firing the leading and trailing on each rotor at the same time.

I was just checking out MSDs webpage and they have a box designed for the viper that allows each cylinder to change timing based on boost pressure. I have been considering picking one of these up for the trailing and have a closer spark at lower manifold pressure and a larger gap at higher boost (It only goes up to 9 degrees, but thats better than nothing). Any thoughts on this or any other modules that MSD or anyone esle sells. I would consider running 3 seperate boxes to do the same, but I can't find those modules any more... I could have sworn they had a boost x rpm ignition adjusting module....

Marcel Burkett

Any one ? , there must be someone with a map/maps I can use .

pluto

[QUOTE]Originally posted by Boostn7
[B]>Generally, I wouldn't go anything higher than 17 degrees (max) on anything below 17psi of boost. <
Hi Pluto, so you don't run more timing at lower boost levels?

I guess I meant to say that I don't run more than 17 degrees on anything above 17psi....Must be sleepy at the time of writing it.



Whever on the dyno(4th gear) I add timing 'till the engine is producing the most power while EGTs remain in a safe zone...if I add 1-2degrees more and only produce 1% or less then I back off the timing.
Reagarding trailing split:
Since I run the Wold3D my split is locked. On the dyno I tryed going from a 15degree split to a 10degrees split all around and notived a 6-8hp gain all around 'till it hit ~5.5krpm @ full boost(18psi) where it took 25+hp loss 'till 8krpm. I raised the split back up to 15 degrees and the hp was back again. Same thing happenned to my friends 13B-REW (62-1 turbo) also with the Wolf3D.
Anyone else noticed gains when adding split at higher boost levels??

Split timing doesn't do anything on my car...maybe 5hp at most by closing my split to 8 degrees. I kept mine at 12 degrees split on the safe side.
I have been playing with half Bridge recently so my setup is a little different than what it used to be. So far, what I found is that if the car runs leaner than 12.1:1 a/f ratio, the car would want to die and starts breaking up(sounds like running too lean from listening to it). My timing is also very conservative since I'm running 25-26psi of boost. Everywhere else on the map kept the same so far. The only changes I really made compared to my old SP map is that I added about 8% more fuel compared to my SP map in all RPM range, lean out certain areas of the map to keep the car idle (idles at 1700rpm) and retarded my timing a little to keep things safe until I figure out what my limits are. From driving it on the street in 4th gear, it seems like the car likes to run at around 11.7-11.8a/f ratio.

Another interesting thing I found is that when I spray N2O, the a/f goes down to about 10.5:1 which wasn't what I would expected since I had the jets tuned so that it doesn't change the a/f too much when I sprayed.

Maybe someone can tell me why my a/f is so rich with N2O???? Should I change my jets to make it run leaner??

My power is kinda down since I haven't made it to dyno tune yet (the only time I put it on the dyno after the b-port, my motor seized up after 3 pulls). I pulled the motor apart saturday and found nothing that could cause the motor to seized up....bearings, housings, rotors, E-shaft were all fine.....I'm so puzzled on this.


I did ran 10.7@125mph on drag radials with a 1.55s 60'. The track was prep too well because I broke my diff casing in half on the semi-final against Titanmotorsports.
I was actually expecting to run a 10.4 on that pass but I would have never thought I would break anything since I don't break much during the elimination.

Kurgan

Steve, you still using an E6K with your setup? Was your 10.7 on Nitrous?

(also, as I mentioned above, I was planning getting the car running this weekend, but it didn't happen, hopefully sometime between tonight and Friday)

pluto

Yep, I'm still using Haltech but hopefully I'll be getting the AEM soon. The 10.70 run was with n2o in the first 3 gears. I turned it off in forth.

SPOautos

Ok, I have a question. If I were to run 15 degree split how would that work or affect the trailing timing when the leading is under 15 degrees. In other words lets say I'm running 12 degrees leading timing, in order to have a 15 degree split I would have to run -3 trailing.....Is that ok???? Do i need to run less split in those areas so that the trailing doesnt go negative???

Also what degree is TDC??? Is that 0

Thanks,
STEPHEN

es

Zero is TDC since that is what the # represents. Degree of advance, or - #'s = degree of retard.

Retarded trailing is fine. I've seen portions of some PFC maps that had retarded leading at low RPM/high boost...

Silver93T

Does anyone know how to read timing with the power fc? I'm seeing#'s in the high 20's. I think I remeber somthing about that value not being on top of 0?

es

It was my understanding that what you read on the Commander/datalogit was actual Deg of advance/retard. There is no ign base like the fuel map.

There are however quite a few correction settings for RPM, boost, air temp, coolant temp...

phlanigan

Back from the dead...

Looking over the stock leading ignition map that comes on the PFC, I see timing advance values up to 25 degrees at high boost/high rpm, while this thread indicates that most tuners use total advance in the teens or lower at this point. I assumed the PFC maps would be more conservative, or am I misreading the map?

I'm still working on getting my A/F values where I want them, but I'd like to implement the information in this thread at some point.

es

Your best bet is to setup your fuel maps to the desired A/F ratio, then start screwing with ignition to get to your desired EGT. If you do one thing at a time it makes troubleshooting problems easier when they pop up...

phlanigan

I understand, and I am just working on the A/F at the moment.

I'm trying to figure out why the stock PFC maps have a more aggressive timing profile at high boost/rpm than tuners have recommended in this post. I know timing advance at high rpm is less of an issue than it is closer to the torque peak, but I'm wondering whether I should immediately retard the high boost/rpm cells on the stock PFC map for safety...

es

Well, I know of nobody that runs the APEX'i maps at boost levels over 12PSI. Maybe that's why?

Sorry I can't offer anything more helpful then that.
Eric.

RX794

The reasoning behind everyone seeing that the PFC runs a little bit more of advanced timing than most tuners reccomend is basically for 2 reasons. #1- The ignition map that the PFC comes with is based on the motor being stock and has no porting, which allows more advanced timing than a ported motor because a stock motor is less efficient and can tolerate more advanced timing due to this.(I hope that came out right) #2- The PFC ignition timing is dead accurate(I've found this to be also true with Electromotive units) and therefore you can advance the timing more than other ECU's because the timing doesn't move, other ECU's have to run lower timing to compensate for the inaccurate safe limits of their ecu's.(I don't wanna start a ECU war here, just stating what I know) This also is the same reasoning behind being able to run no split at basically any level with the PFC or the Electromotive units with no problems.

machinehead

Actually if you look at a stock PFC map the timing is not really that agressive. Yes, you may see timing up to say 24 deg, but that is at 8000 rpm at .6 bar (P16, N20), hardly agressive. Look in the peak torque areas (N 9-12, P16-20) and you will see the timing drops from 16 down to 5. I run more that that on my single turbo map. P20 is 1.4 bar. So at 1.4 bar in the 4500 rpm range that stock map is at 5 deg, nothing crazy about that at all.