Is This Common?

[Legumis]

Just had my exhaust completed by adding 3" dump and front pipes to the existing 3" hi-flow cat and 3" cat-back system.

Problem now is that the acceleration *feels* lazy, especially 2nd gear. Even the dodgy stock boost gauge is peaking a bit lower than what it was. Granted, I haven't got any actual data to show for a loss in power, but its a feeling that I'm getting which is enough for me.

Its not a flat-patch at a certain rev-range, it simply feels that the car is slower all the way through.

Anyone else had this sort of experience?

On the plus side, I can hear the turbo spooling up more now, which I like but that doesn't make up for when I'm getting smaller in someone else's rear-view mirror.

[GTR-32U]

just wondering what boost are you running ? I am thinking the computer is retarding the situation. Any problems with the 02 sensor ?

[Legumis]

I don't have a boost controller so I can only assume I'm running stock boost. That being said, the stock gauge reckons its running at about 9psi (needle *was* right on that middle mark between 0 and +7, now its just under it).

I wondered if the ECU wasn't used to the breathing space but I haven't done anything about that (no piggybacker or reset or anything logical) and I'm pretty certain the O2 sensor is ok. It will be old, but ok and I'm basing that on the fact that the car was doing well before the new pipes were put it. Although, I'm now wondering if the mechanic perhaps had a go at cleaning the o2 sensor. Would that have an affect on the ECU at first, particularly if it was really grubby before?

[r33cruiser]

chuck it on a dyno. its about 60 bucks for 3 power runs.

go from there

[Turbo Dave]

I put FMIC, Pod, Full exhaust and my car went worse than before the mods. once I got my turbo Hiflowed and tuned to suit all the mods...Its a Rocket.

Stock ECU is good for the STOCK setup once you change something the tune needs to change with it. do all the mods you wanna do then get a ECU of somesort either stand alone or piggyback and get it tuned properly.

My car has gone from using 13.5 Litres per 100 to 8.8 Lph, not to mention bucket loads more power on the loud pedal.

and still makes full boost by 3000rpm.

Dave

[Legumis]

I was hoping to get an ECU remap with Dr Drift once I got my boost controller and FMIC installed. Unfortunately I probably won't be able to get the FMIC put in for a while.

What would people recommend so far as an interim tuning goes? Is it worth it, or even possible (without any PFC/SAFC etc), to get some sort of tuning done prior to the FMIC?

Maybe I should resolve myself to biting either one of those bullets: "zero-power" or "empty-wallet" until a proper ECU solution is found.

[R338OY]

A retune will probably be the best short-term solution. While the car gets worked on the tuner can also find out if you've got other factors contributing to power loss.

Or maybe you just expected too much

[OZ_Pomy]

If the computer is the problem why dont you just put the stock dump/front pipe back on then save for the computer then get it all done. Have you checked to make sure it was all installed properly? or did u tell your mechanic the situation?

[limpus]

Nothing wrong with a remap...lots of guys here run remaps with great results...and you're in Melbourne too so you can go to Dr Drift...only problem with a remap is that you do not have a wide range of tuners to go to...

[R31Nismoid]

Yeah as others have said.

I'd get it on a dyno.

Check the AFR's, fuel pressure, boost pressure and other basic things while there and get an idea of where the car it at.

Then workout what area it is thats needing the attention

[Dr_Drift]

R33 - More Flow = Retarded mid range and may well feel slower...

Tune ftw!

[R33Turbo]

huh? so adding a dump pipe *could* give power loss without any tune?

[Dr_Drift]

Yes, or at least the perception of loss..

[10MinuteCar]

what? thats impossible, then why go for an extra dump pipe if you ain't going to tune your car?

What you guys are saying goes against the theory a turbo back gives more power than a cat back (with no tune).

Does this power loss theory with an extra dump pipe also apply to GTT R34's??????????????????

Edited May 14, 2008 by 10MinuteCar

[Adriano]

Does this power loss theory with an extra dump pipe also apply to GTT R34's??????????????????

Its even worse on a 34gtt, i dynod one stock, then he came back with a full turbo back 3.5in, and front mount. It gained 5rwkw up top and lost about 30rwkw everywhere else. Put a pfc on it and got it all back and heaps more.

[Dr_Drift]

As above... The R33 and R34 RB25s both have very conservative ignition retard areas when air flow is increase..

Yes you can loose power, sometimes a lot...