Dyno Fright!

[TommO]

If it was running so lean that it's dangerous, wouldn't the PFC knock sensor detect knock and have an extremely high knock count?

[GeeTR]

AFR tuning is different from car to car - you can run some engines leaner than others it depends upon many factors - fuel density, chamber shape, piston dwell at TDC, piston diameter, spark plug postion, intake and exhuast design, exhaust backpressure - the list is endless.

Well thank goodness 99.99% of people are running RB's on this forum, with a large number of them running the same comparable setups

Edited February 9, 2008 by GeeTR

[The Mafia]

im talking low to mid (75-108k's) to be exact... you could lean on yours at least a ratio in those initial dips safely.... as im guessing the a/fs are taken from the tailpipe and not the dump..

^^^

that there is gospel...

Yes, that is the plan. I noticed this when you see the little bumb in power increase at 75kmph. I've done mostly road tuning so I am not able to see these nice AFR curves to adjust, and also, I only tuned the top end on this one to be a show off at the dyno day. And it worked

If it was running so lean that it's dangerous, wouldn't the PFC knock sensor detect knock and have an extremely high knock count?

12.5:1 and higher I consider dangerous but you don't have room for bad batches of fuel, a idiot driver, or hot days. And there aren't a lot of people looking at the high knock count. They are too busy showing off to their mates.

But in saying all of this, the original AFR plot should be flatter not all over the place.

[rob82]

Well thank goodness 99.99% of people are running RB's on this forum, with a large number of them running the same comparable setups

ohhh I'm sorry all rb produce maximum torque at 12.35467:1 AFR with 22degrees of timing at 6500rpm and 15psi of boost.

Wake up clown, no two cars are similar with even the same mods - that was the point I was trying to make. Its no good saying that there is a certain AFR or timing advance that to achieve X amount of horsepower in all situations.

[futurewa]

Found the original dyno result for the car dating back to late 2005 - click to read, scroll down page

Scale on my dyno - 1AFR= 2 big blocks, or 10 small blocks.

Scale on original dyno below - 1AFR = .4 of a big block

therefore zoom/magnification is 5 times on my graph compared with the graph below. Perhaps that is the reason that Mafia commented that the AFR was all over the show. His AFR probably looks the same at a higher level of magnification.

Edited February 10, 2008 by futurewa

[Edge]

You are looking good for a power run now!

post your dyno sheet after your power run, it would be interesting to see if it has changed much over time.

don't worry about the power numbers, they vary wildly from dyno to dyno, more interested in the power curve shape and the afr.

[Beer Baron]

that is what shits me about CRDs sheets. they always use such a wide AFR scale that everything just looks flat. I mean seriously is there any reason they need to have 2.5:1 to 22.5:1 AFR on there? I would love to see the same graph but with a more sensible scale for the AFR. maybe 8:1 to 18:1 or similar.

[Granthem]

that is what shits me about CRDs sheets. they always use such a wide AFR scale that everything just looks flat. I mean seriously is there any reason they need to have 2.5:1 to 22.5:1 AFR on there? I would love to see the same graph but with a more sensible scale for the AFR. maybe 8:1 to 18:1 or similar.

Great point!

They are probably showing everyone how "flat" they have tuned their a/f ratios. Meanwhile when zoomed in its probably all over the shop

[Guilt-Toy]

I was thinking the same thing, why the hell would they want to read 3:1 AFR ? the sensor wont even read that low !!!

Anyways i like to run the engine rich, 11.6:1 has kept my engine alive on 25psi so thats where its going to stay. Just seems like the guys in sydney like to run em really lean or something, maybe they get paid more money and can afford a couple of rebuilds a year ?? or they want their customers to come back in for engine rebuilds soon after ??

More blown up engines = more engine work needed LOL

*shrug*

that is what shits me about CRDs sheets. they always use such a wide AFR scale that everything just looks flat. I mean seriously is there any reason they need to have 2.5:1 to 22.5:1 AFR on there? I would love to see the same graph but with a more sensible scale for the AFR. maybe 8:1 to 18:1 or similar.

[Beer Baron]

well here is a perfect example. the graph is one of mine. 32 GTR. scale is 10-18:1. Plenty of scope. on scaling like the above my AFR would probably look ruler flat too... but that is not what I wanted anyway.

[Guilt-Toy]

thats a good AFR too! nice tune there

well here is a perfect example. the graph is one of mine. 32 GTR. scale is 10-18:1. Plenty of scope. on scaling like the above my AFR would probably look ruler flat too... but that is not what I wanted anyway.

[Beer Baron]

yeah it's pretty much what I asked for. 11.8:1 for most of the rev range and richening up to 11.5:1 closer to readline to give it a little insurance up top. in reality it's probably a little rich overall, but it's still very punchy, not doughy at all as the extra fuel seems to allow a little extra timing.

[Butters]

Had a quick read through and one thing I think everyone is missing , correct me if i am wrong ?

The tuner said there was too much TIMING !

no matter how much you look at a dyno graph is never going to show that ! You need your dirty paws on the hand controller to see the numbers.

That original graph is pretty wavery up top. Also as beer baron pointed out the scale is 2.5 afr points, so will be VERY up down on a different scale.

Yes you should be seeing knock levels, assuming your knock sensors are working and not disabled.

What knock numbers were you getting on the street ?

I think you will find a good portion of WA tuners will tune on the cautious side of AFR's. There have been a couple of breaker tuners that given WA bad rep, so most tuners very careful now days.

Your car is at what I understand to be a good tuner.

Also Beer barons tune would be the sort of AFR"s i would be aiming at !

Edited February 12, 2008 by Butters

[futurewa]

Knock count on the road, viewed on the Apexi FC Hand controller, 3rd gear, full load all through the rev range - 12

[R31Nismoid]

It says 12.4:1 to 12.6:1 in the mid range.... why do you think that is "way to rich"? If you thank that is way to rich, then you need to re-think your idea of tuning..

Seriously, a safe tune is 11.7:1 to about 12:1 afrs..

12.5:1 and above is considered very dangerous, but I can get away with it due to a fairly obvious reason - WMI

If circuit GTR's can run around with 400rwkw and 13:1

12.5:1 obviously isnt as 'dangerous' as you make it out to be now is it?

[Guilt-Toy]

those gtr's probly get rebuilt after every race.

If circuit GTR's can run around with 400rwkw and 13:1

12.5:1 obviously isnt as 'dangerous' as you make it out to be now is it?

[R31Nismoid]

lol... ah yeah

No.

Most have been together for a number of years now without major issue.

Thats what happens when the build is decent and tune is equally as good

[The Mafia]

yeah but think about:

1. The fuel they use - more stability

2. Engine is built properly to prevent knock

3. They have some of the best tuners in the world doing them

[futurewa]

Finally had a chance to scan my dyno runs -

11LBS AFR Taken at each exhaust (Twin System) (Possibly injectors need cleaning, as the run was terminated due to the knock count going up to 50)

15Lbs Boost 336HP - No knock issue

20Lbs AFR (Not sure which exhaust?) - Run cut...too much knock, up to 50

11Lbs Boost 300HP

12Lbs Boost 308HP

14Lbs Boost 325HP

By my calculations, the 20Lbs run reached 169km/hr in 4th, generating 380HP. The run shown earlier in the post but in 2005, looked like it would have had 10-20hp more at the same speed in the same gear. Possibly the dyno? Possibly my calc?

[monga]

some quick advice mate would be to find a work shop in perth that tunes rb26's often and get them to check out then possibly retune to your needs and wants ( xspeed, top racing ect ), then you know whats safe and whats not.

Edited February 21, 2008 by monga