HELP NEEDED Short on Power after Mods

[wannabe]

Hi All,

I have just had a PFC installed in my Skyline and I was a little disappointed with the final power output. The PFC was tuned by a reputable and well regarded tuner and by all accounts I am happy with the job that was done by him. My disappointment stems from the fact that my car is now running less power with a PFC, front mount and cold air induction and 9 pounds of boost then it just had an SAFC and standard boost.

The current mods are:

Apexi PFC + H/C

Trust Front mount intercooler

Turbo back exhaust with standard cat

Pod filter

CAI + Cold air box

Bleed valve set at 9 PSI

Dyno run was recorded at: 227 RWHP (I would like to note that the power curve is fairly fat) I would love to post the graph but I have no access to a scanner or digital camera at the moment. Sorry

Obviously adding a Z32 or better AFM and dropping the cat will add a fair bit but I still reckon that my power output is a little low for the mods I have.

My questions are:

Does anyone else out there have similar mods? If so what numbers are you putting down?

Can anyone think of any issues that my car may have that would be retarding the performance?

Mechanically the car seems a little bit iffy at times. There is a noise coming from the fuel rail that sounds a lot like ticking. This noise has gotten progressively louder over the last few days. I have recently had the injectors flow tested and they are all fine. O2 Sensor is fine. Further strange engine noise is there is air escaping from the PCV valve on top if the rocker cover. Any problems or suggestion about that?

There is no knock as such being detected, the injectors reach 70 or so % duty cycle

But the car is consitently looking like it is 30HP short of its proposed power figure.

Anyone got any ideas…I know there is a difference with the s1 and s2 AFM’s so would also like feedback from someone with a S2 with similar mods. Any ideas there as I suspect something to do with fuelling and AFM maxing out causing problems.

Any help, feedback or suggestions would be greatly appreciated at this stage as I really want to get the car running well.

Thanks for any replies,

Tim

[Roy]

Maknig less pwer with the mods... were the before/efter power figures doen on the same dyno?

[paulr33]

i have a series II 1997 with 96000 on the clock

hmm, the power does seem a little low for a fully tuneable ecu, given you .

your power is 167rwkw. ive got 141rwkw with stock everything just a pod filter and bigger muffler. not sure what you could check really. the bleed valve could be leaking or something? does the power increase much if you go to say 12psi ?

[strutto]

What sort of dyno is the power readout from?

Have you taken it down the 1/4?

[Col-GTSX]

Throw away that bleed valve... Their death to a motor and turbo...

Mine buggered up at full noise and before i could understand to lift of the gas it had boosted to over 30psi.... BANG BANG BANG.... nah not that bad its slipped a ring....

But it could be a bit leaky and causeing the wastegate to open a little early...

Also that standard Cat is a huge problem... Why get the rest of the exhaust done and leave the cat???

You dont need a Z32 AFM to break 200rwkw... lets aim for that first hey....

Chatter in the fuel lines.... Spend a few bucks there... Get a rising rate FPR (Fuel preasure reg) if you have $500 to spare... Go a serge tank (will also help later for those hard launch's) and a Bosch fuel pump (or VL Turbo pump) and the FPR.... Should only be round $500 fitted...

Remember to get kw's u need....

1. AIR

2. FUEL

3. IGNITION

if you upgrade one component then the rest need to be equal too....

[wannabe]

Thanks for the replies.

I am gonna get the cat replaced as soon as i get some more $$$

The boost does not seems to be leaking as that was one of the components measured on the dyno (Dyno Dynamics in Shootout MOde) Again bleed valve will be replaced when $$$ allows.

I will look into the fuel pressure reg and fuel pump for sure.

Thanks for the advice and keep it coming

[lukits01]

I agree 227hp is a little low with a front mount

My seriesII have the following mounts:

RSR front pipe + standard dump

Trust MX cat back

High flow cat

Apexi Pod filter (without CAI)

Trust V-SPL Intercooler

SAFC2

Profec B EBC

Bosch 910 fuel pump (wasnt connected during the run)

HKS 256 Exhaust cam

on a recent run on shoot out mode made 273.3rwHP on 11PSI!!!

oh and its an Automatic!!

dont think you need a fpr, fuel pump is a maybe.

HPI just did a feature on Z32 metre on a R33, they concluded it did nothing unless you're planning on 300+kw so dont think thats the problem

maybe its the cat or the bleed valve, another possibility is your CAI box is too small and its actually limitting airflow

how was the boost curve?

could post dyno graph if you'd like

[paulr33]

you're making 202rwkw. pretty good. the z32 will help in tuning as when you go running a high level of boost the stock air flow meter will max out at 5.0volts and wont give accurate or correct resolution. it wont add any power but will allow you to run a higher boost (providing your turbo can handle of course) and tune your powerfc to map it properly instead of just maxing out at 5volts. the midpark boost to get 250rwkw ish is around 1.0 bar or more and the stock air flow meter i believe maxes out around there or just above

[paulr33]

btw the automatic shouldnt affect the dyno run by much compared to same car as manual as its max power in 4th gear ,which the auto should do fine, its really in 0 to 100km/h and 1/4 where the manual will be in front, whereas on dyno its just max power, which should be the same, maybe 10rwkw loss max from the auto box

[Steve]

If you can get a rising rate fuel pressure reg, surge tank, and fuel pump fitted for $500 I would love to know where. For $500 you would be looking at a fuel pump and maybe a fuel pressure reg - without fitting, not to mention the surge tank.

Realisitically, unless you are closing on 200rwkw, the fuel pump isnt really needed. At around 200 mark it would be worth doing.

the cat is killing power, no doubt about it - back pressure is bad.

I would remove the bleed valve and plumb it back up the way the factory did. 9 psi is stock boost with a cat back, so it isnt helping at all. Better still wind in a bit more boost, try around 11-12psi. Seeing as you have a decent front mount, it will be fine.

The rattling from the fuel rail? did you know that the injectors make a rattling noise, all do it. If you know someone with a skyline, check to see what theirs sounds like.

Noise from the PCV valve. This will happen when their is vacuum in the plenum - its supposed to. It is sucking out the crank case gasses. If air lleaks under boost you have a problem. Try removing the valve, and checking that it only allow air to pass in one direction, from the rocker cover to the plenum. If it does all is good. If it allows air to pass both ways you have two options. 1. buy a new valve, which you should be able to pick up from somewhere like autobarn, or 2. block the valve off. This will have no detrimental effect other than maybe causing the idle to change a little, as it isnt sucking air in from the rockers anymore.

A common thing to check, every intercooler pipe, vacuum line and anything else you can find - to make sure you have no vacuum leaks. Most skylines are a few years old, and leaks do happen. Also make sure you check your boost guage if you have fitted one.

good luck.

[The Mafia]

I am having the exact same problem. I have a Series II 96 with 77,000kms on it. It was in absolute immaculate condition when I got it, and it still is.

I have a FULL exhaust (custom dump and front in one which my best mate made from stainless, high flow cat, and 4 inches after the cat), a Front mount 600x300x76, boost running at 7psi until it hits 5,000 rpm, then goes to 10psi. If I open up the Apexi AVC-R the car boost cuts, and the dyno reads 30kw's less at the wheels.

Its pissing me off seeing this little power. At 9PSI, the car only did 142rwkws.

[paulr33]

ive got 141rwkw with stock everything in a series II, just a pod filter and 4" muffler

[GTR32]

Hi All,

The PFC was tuned by a reputable and well regarded tuner

Hi Tim;

What does the tuner say about the lack of power?

Regards

[rev210]

the power figure looks ok to me. The engine is probably not 'new' , I'm guessing the better part of 100,000kms?

The standard cat if very old can easily strangle power.

Whack some camshafts in, it will do wonders for the power curve even on a factory turbo.

[wannabe]

Hey all,

Thanks for all the responses and apologies for not getting back online sooner. I have limted net access:(

Right to answer all your various queries & theories:

Lukits01: The CAI box is quite large and has direct air feed from front bar, as a result i would say that there is AT LEAST as much air available to the engine as with standard set up. The boost also seems very stable as it was one of the things measured on the Dyno. Stays at 9psi with a 0.2ish spike over 6500 rpm. Nice dyno reading for your car BTW.

Paul R33: By my calculations i am making about 160ish rwkw. So i think that i have a bit more power to expect but i may be wrong?

Steve: When i had my stcok boost (2 weeks ago) with my full turbo back exhaust, apart from cat, the boost was reading about 6.8 PSI flat out in 2nd and 3rd gears on my PFC and after market boost gauge. So the bleed valve has upped the boost a bit. As for the current boost levels, i did have it set to 10PSI (i wanted a little more but am have the series II turbo and wanted to be safe-ish with the spike) the tuner reduced it to 9psi and told me he did that because there is only so much air that the standard turbo can push and any more is a waste. The rattling from the fuel rail may well be the injectors BUT they have gotten much louder of late (in the past 2 weeks or so) even the tuner remarked that my engine was making some funny noises. I changed the PCV valve it was PERISHED to the point of being totally worthless. The leak has stopped as a result of this. I checked all hoses and pipes and ther were no other leaks that i could find.

THE Mafia: I feel your pain of not having the power that you expect

GTR32: Good question. The tuner says that he thinks that the power is right and if i want any more i have to get a new AFM and take it back and he can get a little more for me. He also advised me to get a better cat.

Rev210: Thanks for your feedback and advice. I am hoping not to spend too much more on my car for a while but a jap spec cat is on the cards. Cams, fuel system and flywheel will be the next mods but a little further down the track. BTW the car has 60k kms on the clock.

Thanks again for all the advice folks. I am not too sure what to do but i will post any developments on this thread.

Cheers Tim

[EnricoPalazzo]

if ur tuner turned down the boost to 9psi to be on the safe side, i would say he has no idea about tuning skylines. Its not boost that will kill the engine, it would be a bad tune in which u would run lean. too much boost would blow turbo. i would try and find a new tuner, get it tuned to 13-14psi, and get rid of the cat.

[Steve]

If you were only making 6.8psi with cat back, I would say you still have some pretty serious back pressure issues.

You gotta let the car breathe, more so on the exhaust side, as back pressure absolutely kills power! Get rid of the stock cat, and take a good hard critical look at your cat back system. I went from an N1, which I replaced with a Nismo system, as the N1 was too loud, and lost power everywhere - it was quite dramatic. I have since upgraded to a HKS super dragger.

What I am getting at is not all cat back systems are equal. If its quiet, it will be killing power.

Best way to test, if you are sceptical (and probably good to try either way) is to get the car on the dyno for a power run with the exhaust dropped - takes about 10 minutes to remove. It is a pretty cheap way to find out for sure.

[Robo]

Have to agree....

Stock turbo can certainly handle more than 9 psi..

I would say you can expect:

-> 5-10 rwkw's with high flow cat

- > 5-10 rwkw's from boost increase (I would say 11-12 is good and safe)

With your current set up you have about 170 rwkw's (roughly) and with the above SIMPLE mods you can expect to achieve around 190 rwkw's.

What are your air fuel ratios set to at peak power?

The above mods are cheap and simple..

You may have to get your computer re-tuned tho..

Have fun.

Rob

[wannabe]

Steve thanks for the continued replies & Robo thanks for your input...

The cat is going to be exchanged for a high flow unit this weekend. I will play around with the boost also.

As for AFR's i will have to get back to you on that...