What ignition advance do you run?

[Sydneykid]

hi SK,

i have a question regarding your response above given that you've had experience with engines like mine, what are your thoughts on the YBD Sierra Cosworth engines?

the reason i ask is b/c i am looking installing different spec cams in my engine in the near future, as to gain more power/torque in the mid-high rpm range with less/same boost.

also, i would like to know what your recommendations are regarding cam specs for my engine (street & soon circuit/track car).

thanks in advance.

As I have mentioned in the past I don't have a very high opinion of Sierra Cosworth engines, I had to rebuild far too many of them, far too often. Like the FJ, good design for their day, but time marches on. Standard engine improvement techniques apply of course. Cosworth have some good camshafts designed for that engine, at least 10 combinations of timing and lift were available when we were racing them. Larger valves were also available as were titanium followers, collets, steel guides, titanium spring steel valves springs etc etc. I don't know how much is still around, but there used to heaps.

[180bfj20det]

hey there dude,

regarding your engine, CR, timing etc, running higher compression is obviously better as it brings better turbo & engine response which makes the car feel better to drive down low.

why don't u keep the engine as it is, and run higher octane fuel (i.e., elf turbo max). this will allow you to have the best of both worlds, a high compression engine, running high boost and more ignition timing advance.

if i ever rebuild my engine again, i'll definitely go this way, but then again i have forgies  ;-)

Also, how do u find the GT30R with A/R .82 exhaust housing, does it feel laggy/doughy?

Only want to run pump...

The GT30R isnt that laggy surprisingly. It makes full boost at 4000rpm.

[180bfj20det]

Thanks for the reply. What I should really say it what Im aiming for and why.

Aim: I want 350rwhp on pump.

Why: Because I know of at least 10 FJ20ETs making this power with the stock engine on 18 psi on pump (To4s, GT30s etc).

I have a friend who makes just 30rwhp less than me and runs a t28 of the early 200sx so there is a problem somewhere.

The differences bt the engines are that mine is the FJ20E and theirs are the FJ20ET. Also, there is no difference in power delivery bt mine and theirs up to about 285rwhp where I stop the steep rise of power (then make flatten off to make my peak power) and they continue a good 35-40hp before they flatten off to make peak power... so they have more average power plus more peak power....

I think there must be a difference in the head as well as compression bt the NA and turbo engines (although this is contrary to dogma). I will just get an FJ20ET and bolt everything on and hope for 350rwhp. This is trialled and proven and I want to be part of it. What are your thoughts on the differences bt the NA and turbo engines in terms of my 307 vs 350hp and do you think this will make the difference? Also, I have driven the 350rwhp FJ20ETs and they are as tractable as mine (well so it seems....so drivability isnt hugely comprimised cause I cant feel it).

I just wanna make the trialled proven 350rwhp. If you think compression is not the problem...then what keeping my ignition timing so retarded? Please say you dont think its compression if you really think so cause I need to know.

Cheers

Thanks SK

[Cubes]

First.. Have a look at your exhaust. Make sure its flowing well.

The RB30DET on 12psi with peak torque at ~2000rpm was only able to take 17degree's.

Apparently the motor has an 8.2-8.3:1 comp ratio, my calcs give higher comp but who knows.

Through the mid it drops down to 16degree's then picks back up to 17degree's by 5000rpm. It was really only a rough tune with a small restrictive hotside with N/A cams that have a little more overlap than T cams.

The rb20's stock map runs around 19-20degree's through the WOT load points.

What interests me is the low/mid load ignition curve, how a longer stroke affects the ign. timing. I'm still running around with the rb20's low/mid load ignition curve.

How does one determine how to set this up on a dyno?

I would think its impossible to get it right. Or does the EGT tell a story with low/mid loads?

If only I could grab hold of a VG30DET's low/mid load ign. curve as they run an almost identical bore, stroke & comp combo. or possibly an early SR20det ign curve.. Would be interestering to compare.

[Sydneykid]

How does one determine how to set this up on a dyno?

I would think its impossible to get it right.

It's actually very simple, advance it till you can hear pre-ignition (or see it on the PFC knock sensor readings). Then retard it till the power drops off. Once you have 3 or 4 reference points, then join them up on the map. Maximum ignition advance (just prior to pre-igntion) usually makes the most power.

[Cubes]

Maximum ignition advance (just prior to pre-igntion) usually makes the most power.

Thats exactly my line of thought, however, is this method really definitely true when determining low to moderate load levels? After all the goal is still the same, obtain as much power/torque as you can from x air and y fuel?

Please say yes so I can go out for a drive and dial in 40+ degree's ign timing lol.

For example, on idle the car won't knock it will simply run rough as it struggles to spin over. Maybe in this instance slight load would have it detonation, I don't know.

The RB30DET really doesn't have any problems accelerating from 1500rpm in a high gear, to get the ign. timing optimal at this point would obviously improve fuel economy. The RB20 pfc map at these moderate load points are only running 16-25degree's of ign. timing.

The reason I ask is I've played. I admit it, I'm a fiddler.

I jammed the wastegate right open and cranked the ignition timing in to it.

At low engine speeds with full throttle load it is still able to handle 37degree's advance without any knock, well I can't hear knock and the pfc knock sensor is not showing any.

MAYBE?!?!?!? the lowish comp ratio will allow it to take even more than 37degree's.

I don't want to push in to it any more than 37degree's with a high low or moderate load as I fear it may damage something, UNTIL I understand how a motor responds to too much ign timing at low/moderate loads.

Is it possible to not detonate at low engine speeds yet still damage the motor due to it working against its self.

I do change back to the origional map after my fiddlings, I wouldn't want any long term damage caused by driving around hundreds of kays running way to high ign timing.

UNLESS this is the PowerFC's 'conservative' ign. I've heard you speak of previously. I do remember watching the rb20det's stock ecu run 28degree's ign timing as it was on boost, knock was detected and timing pulled to 8 degree's. Would it be correct to assume the stock ecu's run much more low/mid load ign. timing?

The RB20det stock ecu DID feel like the car had more torque off boost and got on to boost a little quicker/easier, the pfc felt noticeably flatter.

I need a rolling road in my shed. I would love to play and fiddle to fully understand 'cause' and 'effect'.

:confused:

EDIT: Any one care to post their Ign map?

Preferably a fully worked over map not just a slightly modifed WOT map.

[gtst25]

Took a photo of the graph we made from the timing map on my PFC.

It doesn't take very long to write down and then transfer onto the computer.

I'd be interested to see anyone else's - good to compare.

I'm thinking about getting a lambia sensor to do some light load tuning. The dyno tuner who did my tune seemed to just try to get power - which he did but I would've liked to see him take it for a drive with the lambia.

Cheers

[Sydneykid]

The above is the default Power FC ignition map for an RB25DET, note the number of load points at 40, 41, 42 and 43 degrees. This is why the standard maps give such a responsive package, but are close to the knock window when run on lower ron fuel.

Experienced tuners set the low load ignition timing by feel, however the starting point is as always "advance it till it pings and then knock it back a little". A/F ratio readings will go off as the best ignition timing points is past, but that is a long drawn out process. Tune it on feel is the quickest way I know off.

[discopotato03]

Yes have to agree , the FJT is a bit dated by todays standards . From the few people I know who got large power numbers from the OX , derestricting the exhaust side was critical as was turbo selection . One I do remember did 700 crank HP on an engine dyno but it was no boulevard cruiser . I think it used oversized valves , a fair bit of porting on the exhaust side , fairly big cams , a TA45 Turbo and 1.5" bore steam pipe exhaust manifold - the external gate was a large HKS ie 50 - 60mm . It had a custom inlet manifold with a huge throttlebody and huge Rochester injectors .

With OEM cams I think you'll find the lobe center lines is slightly more aggressive on one of them I think the NA inlet cam , it wasen't just the phasing that was different . Also you may find the NA compression ratio is higher than you think , I have seen numbers in Nissan manuals mentioning 9.1 and 9.5 at least for the S12 version .

I would look into the GT30's exhaust housing , I sincerely hope you'r using a propper GT30 housing not some machined out substitute . If so you could look at the largest 1.06 ARR housing which may help but as SK mentioned head and cam upgrades do pay off . There is a golden rule with efficient turbocharging - keep the exhaust manifold pressure down to somewhere near boost pressure . You should take a line off your exhaust manifold before the turbo and run two pressure gauges to compare exhaust and inlet manifold manifold pressure . If you have major restrictions they'll show up .

Cheers A .

[Cubes]

The before after of my tune.

Modifications marked in red with the rb20 base map on a different sheet so comparing is easy.

Sorry for being slightly off topic.

[Cubes]

Here are the R33 RB26DETT & R33 Rb25DET PowerFC Base Ignition Maps.

I grabbed them from the Apexi PowerFC Software, They appear to be spot on as the RB20DET base map in it is exactly the same as the one in my PFC.

Note the 2000rpm Highload ignition in the rb26 map. 26degree's lol.

[gtst25]

The before after of my tune.

 

Modifications marked in red with the rb20 base map on a different sheet so comparing is easy.

 

Sorry for being slightly off topic.

Great to get some ignition maps up to compare.

So does your car go right up to load point 20 Cubes?

Mine only gets to 15 or 16 under full load - from looking at your graph it looks like your tuner has done a lot of work in the points marked in red 17 to 20, and a few changes earlier.

[Cubes]

Yep thats right mine has always used the complete map.

On a cool night it will hit load point 20 from as low as 2400rpm with 12psi and the stock rb20det turbo.

Generally it sits around load point 19 on WOT.

Light general traffic driving (only touching the accelerator off boost) see's load point 13-15.

Cruise at 100km/h seels load 7.

I've moved to a Z32 AFM and found the map not to show any difference with regards to load points at all.

The only difference is now instead of hitting just under 5v it now only just hits 4v.

I'm not completely sure what is going on as I've heard a few others stating they too only hit 15 or 16, some even only 11 at WOT.

I assume it has some thing to do with the stock 'BASE' RB20DET, After all in the PFC manual for major cam mods etc it states you will have to use the software to modify the real map.

I think that is refering to the fuel map though. i.e 100 = 14.7afr apparently.

Suprisingly the RB20DET PFC base maps fueling was almost perfect, no lean spots however it was slightly rich through the low and mid, it then goes lean over ~6000rpm, max duty cycle is seen at around 5300rpm.

---------

I kept the WOT modified part of the map and integrated the RB25 ign. map. It actually appears smoother at low rev's when initially letting out the clutch and idling around car parks.

[180bfj20det]

Yes have to agree , the FJT is a bit dated by todays standards . From the few people I know who got large power numbers from the OX , derestricting the exhaust side was critical as was turbo selection . One I do remember did 700 crank HP on an engine dyno but it was no boulevard cruiser . I think it used oversized valves , a fair bit of porting on the exhaust side , fairly big cams , a TA45 Turbo and 1.5" bore steam pipe exhaust manifold - the external gate was a large HKS ie 50 - 60mm . It had a custom inlet manifold with a huge throttlebody and huge Rochester injectors .  

With OEM cams I think you'll find the lobe center lines is slightly more aggressive on one of them I think the NA inlet cam , it wasen't just the phasing that was different . Also you may find the NA compression ratio is higher than you think , I have seen numbers in Nissan manuals mentioning 9.1 and 9.5 at least for the S12 version .  

I would look into the GT30's exhaust housing , I sincerely hope you'r using a propper GT30 housing not some machined out substitute . If so you could look at the largest 1.06 ARR housing which may help but as SK mentioned head and cam upgrades do pay off . There is a golden rule with efficient turbocharging - keep the exhaust manifold pressure down to somewhere near boost pressure . You should take a line off your exhaust manifold before the turbo and run two pressure gauges to compare exhaust and inlet manifold manifold pressure . If you have major restrictions they'll show up .

Cheers  A .

Thanks for the info. The FJ maybe dated...but it certainly is a more robust engine than say the SR20 and has more similarities to the GTR engine than the latter too!

Anways my GT30 is a genuine Garrett GT30R. I will test the exhuast pressure tho I hope this is fine because a 0.82 housing is quite large for a 2L. I will first get a FJ20ET and try and get the 350 this way. This will work and then I will do further mods from there which is better starting off with the better engine.

Cheers

[gtst25]

Yep thats right mine has always used the complete map.

 

On a cool night it will hit load point 20 from as low as 2400rpm with 12psi and the stock rb20det turbo.

 

Generally it sits around load point 19 on WOT.

 

Light general traffic driving (only touching the accelerator off boost) see's load point 13-15.

Cruise at 100km/h seels load 7.

 

I've moved to a Z32 AFM and found the map not to show any difference with regards to load points at all.

The only difference is now instead of hitting just under 5v it now only just hits 4v.

 

I'm not completely sure what is going on as I've heard a few others stating they too only hit 15 or 16, some even only 11 at WOT.

I assume it has some thing to do with the stock 'BASE' RB20DET, After all in the PFC manual for major cam mods etc it states you will have to use the software to modify the real map.

I think that is refering to the fuel map though. i.e 100 = 14.7afr apparently.

 

Suprisingly the RB20DET PFC base maps fueling was almost perfect, no lean spots however it was slightly rich through the low and mid, it then goes lean over ~6000rpm, max duty cycle is seen at around 5300rpm.

 

---------

 

I kept the WOT modified part of the map and integrated the RB25 ign. map. It actually appears smoother at low rev's when initially letting out the clutch and idling around car parks.

Which rb25 ignition map did you integrate? Sydney Kid's base map or mine?

I'd say the reason why you goto load point 20 is the extra capacity of the engine - it just breathes more.

I'd like to know what the numbers on the fuel map stand for.

On my map they start on 99 and go up to 149 at the highest.

When I plugged in the pfc and drove it around for awhile I also found it ran a bit rich.

When the bloke dynoed mine he first got the boost right (after checking afr's weren't too lean - it was running quite rich ) then the AFR's, then the timing. This took quite awhile - at the end he mucked around with all three a bit.

I'd still like to go for a drive with a lambia sensor to see what the afr's are - it'd be interesting to see what's going on.

What's the highest AFR you can safely run when just say cruising at 100km/hr?

It'd be interesting to see how good fuel economy you could get - although from what I can gather the pfc's have that set 14.5:1 afr when running in closed loop?

[Cubes]

I had a VS V8 commodore previously that was remapped and leaned out close to 17:1.

The problem with this is if EGT's arn't monitored and you can't get enough ign. timing in to it the EGT's will kill the cat really quick.

The VS 5ltrs are fine with 17:1. But thats no good to us!

SK's base map appears to be a modified map, I used the Apexi Software's base map. Yours UNFORTUNATELY I couldn't read too well

Can you possibly email me a good copy that I can read the numbers?

I'm going to have a chat to my tuner that has the PFC software.

I did have a cheap tune done by a local bloke which is good for now. Until I stick the bigger turbo on.

[180bfj20det]

Hey disco potato....that 700hp fj, do you have any other infomation on it, websites or would you have the contact of the person who owns (owned) it?

Do you have an MSN address so we could chat sometime? PM it to me if you wish... if not, its cool

Cheers

[RedDrifter]

Heres a pic of a stock R32 GTR ignition map(eccs)

[180bfj20det]

Heres a pic of a stock R32 GTR ignition map(eccs)

Shite GTRs love their timing!!!!!!!!

[RedDrifter]

Shite GTRs love their timing!!!!!!!!

Yeah they sure do.

Thats the base map I'm using at the moment for my RB20DET.

The timing is fine untill just after the 64 load point. Neads to be backed off a little as it pings slightly if I run any higher than that.