T5 tuning problems

[arjenvaalburg]

Hi guys,

I'm in trouble... I bought a V70 T5, 2003, manual gear. Nice car to drive. Wanted some extra power so went for a chip tune at a respected tuner (they have done an number of T5's). Results before/after: see graph. No improvement. Zero. So my trouble is stated.

before_after

Explanation tuner: spark plugs and/or MAF/airflow sensor. The MAFsensor was cleaned, the car ran marginal better, higher torque/power low RPM. Nett max. result: +4HP. The car seemed to doubt/hesitate around 2.500 rpm.

I replaced the plugs, ordered the MAF (and Turbo Control Valve). In the mean time went for another down pipe / exhaust. 3,5 (elbow) > 3 (incl. hat) inch (see attachment).

3,5 inch Fat down pipe

So a pretty fat one. Before installation of the new down pipe/exhaust system, i made a picture of the turbo (see picture). My T5 runs on blue injectors by the way (395cc, which I figured to be okay.

Turbo in shape?

Installation of the new exhaust give a bit more smooth and some extra power, but I would call it marginal. The 2.500 rpm issue stayed.

Today installed the TCV and brand new sensor. No improvement, hesitation at 2.500 rpm still there. I pulled real hard up and down the road a couple of times. Opened the hood, down pipe starting to glow. So drove home real easy.

Questions:
1. Any idea on the 2.500 rpm issue?
2. Do you think the turbo looks alright?
3. Is the glowing of the down pipe normal after some hard pushes?
4. What could cause the curve pattern (seems to die at 5.000 RPM)?

Hope you have an idea that could help me further.

Thanks, Arjen

[RobTarD]

It's possible that your engine is running lean due to the new exhaust. Check your lambda sensors.

It's normal for torque to drop off at high RPM.

[ChiNorm]

I question the tune you purchased. I popped and IPD stage 1 chip into my 96 854t5 and recieved a large imdediate increase in performance without any other changes. Pray tell, whose tune did you use?

Good luck.

[mercuric]

1) You should be logging ignition advance, boost pressure and A/F ratio along with your dyno plots. Ignition advance can be had via OBD-II info, boost pressure obviously from a simple pressure sensor and A/F ratio from a wideband sensor. These are the key things that make power, so..

2) Not all T5's are created equal. The first T5s (850s) used Motronic 4.3, then Motrontic 4.4, 7 and later followed. Each one is quite unique and a different animal to tune.

3) Failure of ECU tuning to change output is generally a problem with the tuning done, not the mechanical hardware, especially when the car runs to within stock specification before tuning. More often than not, the tuner fails to change all the necessary maps -- For rough example, upping a boost map without also raising a MAF limiting map, or something similar. There's a lot of variables to a modern engine control computer, but I'm honestly not familiar with MY2003 T5 ECUs.

4) Your glowing exhaust probably indicates whatever ignition and fuel map values you are using are not correct. Go back to the stock program and go from there.

Personally, with high EGT and more gain in torque than HP, I'd think they added boost without properly massaging the A/F ratio, andpulled timing to compensate.. or the ECU is pulling timing to avoid knock. Timing retard under boost greatly elevates EGT. Too much advance will too, but retard generally has a more pronounced effect.

If they're doing dyno runs, why aren't they working on the ECU program? Isn't that the whole idea of doing dyno runs?

[mercuric]

I question the tune you purchased. I popped and IPD stage 1 chip into my 96 854t5 and recieved a large imdediate increase in performance without any other changes. Pray tell, whose tune did you use?

Good luck.

Yup. The factory boost map on the 850T5's is really conservative, especially on the automatics... It's unreal the difference just fleshing out the curve from 3500-5500 RPM does...

[matthew1]

arjenvaalburg, no CE light / codes before the tune? How about now?