Reading Dyno Graphs

[Klymax]

Hey guys.

I took my 34gtt in for a tune to sort out the richness as its a daily driver. Sorry for the quality of these pics but i took a few to make reading easier. The power is low compared to (probably all hehe) but thats not what its about. I'll get to the point. as you can see theres a red line (run 1 from when the car landed at my door) a green line from the 7th run of my tuner playing. and a purpley line for teh 8th run. im wondering why there was a huge spike in it at around 120klm/h I actually havent seen another dyno look like this and Im not even sure what conclusions can be made from viewing the graph.

theres a manual boost contoller @ 10psi

3" blitz catback

Neo AFC

Impul ECU

panel filter

[666DAN]

VCT turning off probably

[R31Nismoid]

Looks like the stock ECU having a fit due to too much boost.

Every ECU cracks it at a different level.

Back off the boost and then see what happens... surely your tuner did that at least?

[paulr33]

yep ash is spot on, its the stock ecu doing its usual protection

recommedn action - look and read up on

- piggyback devices to work around

- remapping standard ecu

- stand alone ecu

- dropping boost until you get a normal curve

then decide which path you want to go down

[some_cs_student]

yep ash is spot on, its the stock ecu doing its usual protection

The first post mentions and "Impul ECU". Whats an Impul ECU?

[paulr33]

ah yeah its a remap of the std ecu

and you have an safc as well

what did you ask for-

a tune?

just a dyno run/health check?

its could just a case of a few points arent setup properly

what was it like before they 'tuned' it

[Klymax]

Hey guys, thanks for teh feedback.

paulr33 - Yeah mate, jsut a general "see where its at" tune. it was running extremely rich when i bought it and heres some pics of the ECU

R31Nismoid - From what i see with power increase, i guess the tuner was upping the boost until it "cracked" that point? its apparantly at 10psi so it shouldnt be too high for the ecu should it?

666DAN - What VCT mate? sorry im still not very knowledgeable on alot of FI things.

I just assumed (heeh assumption is the mother of all....) that with only 10psi, decent flow in an out of the motor and a AFC i would have a not high power but a nice steady delivery.

Where should i go from here? get rid of the impul and neo and replace with a powerfc, add a fmic and dump/front, poosibly a pod with CAI before returning for a retune?

[GeeTR]

The 8th run, the pink one, looks like AFR's go v.close to 12.8 just before the dip in power... in fact it looks dead on.

From what i understand about NEO's with their compression, thats pretty lean. Could the ECU have pulled ignition due to knock?....assuming the IMPUL ECU keeps that functionally.

My 2 cents

EDIT:

666DAN - What VCT mate? sorry im still not very knowledgeable on alot of FI things.

Lol, VCT is more of a NA, Vtac thang! It refers to the varying inlet camshaft timing.

Edited May 25, 2008 by GeeTR

[666DAN]

Everyone seems to think the R34 ECU is a clever bit of gear, it really isn't. the R&R is more like "R" as that's where the R34's drop the power through aggressive retarding (see attached stock fuel and timing maps) at 10 psi you'd still have 3 cells to go on the load scale, you'd be sitting about 176 & 128 respectively. Especially as the SAFC Neo is fudging the AFM signal.

I still think it's the VCT shift point (variable inlet cam timing) as that's exactly where my one came into play, then got ironed out with some timing advance to make the overlap less noticable.

[666DAN]

Could the ECU have pulled ignition due to knock?....assuming the IMPUL ECU keeps that functionally

The R34 only swaps between 2 timing MAPs, nothing fancy...I think it is pushing it at that AFR ~4000rpm the R34's are pretty sensitive to ignition timing around there.

Lol, VCT is more of a NA, Vtac thang! It refers to the varying inlet camshaft timing

R34's have VCT? How's that NA?

[siddr20]

Perhaps try and borrow a stock r34 ecu and see how the car feels.

Maybe the impul ecu has had a crap tune.. Dc the afc as well..

I think this might be the cheapest option.

Then start from the start i guess..

But speak to your mechanic/tuner first and see what he thinks.

Also 162kw seems about right with just an catback exhaust as mods. and bit more boost. However not to sure about the neo engines. For non-neo rb25s seems about right..

Edited May 25, 2008 by siddr20

[DECIM8]

Its a GTT with 160rwkw with those mods? Seems your missing alot of power id expect at least 20 more rwkw as im only running a FMIC, Highflow cat and a dump pipe with about 220rwkw. So really its only flow difference between us?

Also I believe Dan is right that is deff VCT turning off.. Does so at 5000 rpm or somthing does it not?

More to the point at that point without regapped spark plugs to 0.8mm your would be hitting the standard skyline flat spot which is very clear once you turn up the boost on the r34. REgap your plugs (buy new ones regapped) to 0.8 and you should see a performance increase. get a front pipe and cat and it will minimise flow restriction so will drop "drop" down

[Klymax]

It goes in shortly for a 80 thou service in teh next week, so ill try a get a front/dump, cat and plugs asap an have them on the same time. Maybe ill see some improvement on this drop.

Cheers guys

[Adriano]

Its a GTT with 160rwkw with those mods? Seems your missing alot of power id expect at least 20 more rwkw as im only running a FMIC, Highflow cat and a dump pipe with about 220rwkw. So really its only flow difference between us?

Also I believe Dan is right that is deff VCT turning off.. Does so at 5000 rpm or somthing does it not?

More to the point at that point without regapped spark plugs to 0.8mm your would be hitting the standard skyline flat spot which is very clear once you turn up the boost on the r34. REgap your plugs (buy new ones regapped) to 0.8 and you should see a performance increase. get a front pipe and cat and it will minimise flow restriction so will drop "drop" down

Your making 220rwkw with a stock ECU?

[DECIM8]

Ive seen Mr R34 runs 240rwkw with stock turbo too (14 psi)

So yeah its like 219.2rwkw or something, most people run 215rwkw or close on the neo with stock pc .. Oh wait ive got safc too. my bad

Oh I run 11psi - 13psi depending if its day or night.

Edited May 25, 2008 by DECIM8

[Klymax]

Alrighty, Decim8,

Checked my plugs out. found out they are already gapped at 0.8 and are ngk irid's in there. the coilpacks also look rather new and have a rubbery wrap around them ( thought i'd check as i've read about the r33's having cracks in them) so that area looks all good. I guess ill wait for the front/dump and hi-flow cat to see what happens then. I put on a pod but dont know of how i can get some cai happening for now but ill tend to that later i suppose.

Also i hear the stock boost gauges arent accurate. if i click my manual boost controller down for say 5 clicks. and tromp it. i feel a definate loss of power, but my gauge still hits near top 1 bar. and if i up the boost back by 5 clicks. same thing. so i cant really tell if im getting a boost drop or something.

cheers

[GeeTR]

Could the ECU have pulled ignition due to knock?....assuming the IMPUL ECU keeps that functionally

The R34 only swaps between 2 timing MAPs, nothing fancy...I think it is pushing it at that AFR ~4000rpm the R34's are pretty sensitive to ignition timing around there.

Lol, VCT is more of a NA, Vtac thang! It refers to the varying inlet camshaft timing

R34's have VCT? How's that NA?

Oh, R34's switch? I thought they might gradually pull (like water temp correction)

VCT - I meant to imply, variable cam timing (or any sort) was developed and used primarily by NA cars as a power adder (or to lower emissions, as i believe RB's are) before FI

[stolen_s15]

Ive seen Mr R34 runs 240rwkw with stock turbo too (14 psi)

So yeah its like 219.2rwkw or something, most people run 215rwkw or close on the neo with stock pc .. Oh wait ive got safc too. my bad

Oh I run 11psi - 13psi depending if its day or night.

240kw on a stock tubo is pure uncut colombian fantasy land! Remeber dyno figures are only as good as their operators.

[R31Nismoid]

Every 12 months the dyno results get higher and higher, first it was 200rwkw in '06, then 220 in '07, now 240 '08 on a stock turbo?

Please... 240rwkw on a stock turbo is a load of rubbish. Get out there and run a 112mph (minimum) pass and i'll believe 240rwkw.

IMPUL ECU doesnt mean a lot, just a chip etc really, with an unknown map it almost makes it more of an issue than the stock ECU.

Also - didnt the Tuner tell you how much boost you were running?

Honestly i think the place your choose for the work is being fairly lazy with all of it. If possible i'd head somewhere else... although being Darwin your probably restricted in that matter.

Also 1bar on a stock turbo, is silly.

[nizmonut]

Every 12 months the dyno results get higher and higher, first it was 200rwkw in '06, then 220 in '07, now 240 '08 on a stock turbo?

Please... 240rwkw on a stock turbo is a load of rubbish. Get out there and run a 112mph (minimum) pass and i'll believe 240rwkw.

Also 1bar on a stock turbo, is silly.

yeah i tried telling some one else here that...

the rb's VVL is variable valve lift.... not variable cam advancement/retardment, it is not

like a honda vtec.

under each cam lobe is a hydraulic lifter that acts like a mini hydraulic ram expanding and contracting depending on the oil pressure and how much oil the ecu lets flow via the solenoid controlling it.

on a normal non vvl rb these hydraulic lifters are replaced by normal solid buckets.

when this occours it creates more lift increasing the airflow around the valves as it enters the

combustion chamber.