Remap not making expected bhp !! Advice please

[ant schof]

Hi All ,
I've owned my S3 02 plate BAM for just over two years now and more than happy with it even with the ups and downs . I'm an avid forum reader but don't often post . So this last week i decided it was time to up the power , i fitted a greddy's medium size FMIC , also have a catch can fitted and autobahn tip . And took it to a reputable tuner here in the southwest . They did a scan on the car before the first dyno , no fault codes stored , bar a G85 clockspring issue which i was aware of although there fault reader was'nt a full vagcom version on that day . Results came in as follows , BHP 217 and Torque 214 lbft . slightly under standard but not too bad i thought . So they proceeeded to map it , however the power graph was decidedly wavy and after four dyno runs , they took the map back off and put back to standard . Suggested i replaced the N75 and Boost valve . So off i went , bought and fitted a new N75 and brand new 007P . Then returned two days later to Map again , and scanned with full VAGCOM still no codes stored , this time they found standard BHP had gone up slightly and decided to Map again , however on completion again a very wavy power graph i've now got 235 BHP and 259lbft . I was hoping to acheive 268 BHP . So my question is how can i make the expected torque but not the BHP !? also i'm wondering if i may have a turbo issue as the car is a hell of a lot faster but on boost around 3000 to 3500 rpm i can hear a high pitched squeal which goes again after this RPM , any input much appreciated


Ant

 

[Broken Byzan]

did they smoke test it or log it on the dyno to test for faults?

Squeal could be a boost leak or cavitation from asking for boost at incorrect times, sigh.

 

[hughjass]

For me torque is what you want as bhp should be calculated from it. IMHO

I blatantly copy and pasted this while doin a google (maybe heavy reading);

The following examples illustrate several different values of TORQUE which produce 300 HP.
Example 1: How much TORQUE is required to produce 300 HP at 2700 RPM?
since HP = TORQUE x RPM ÷ 5252
then by rearranging the equation:
TORQUE = HP x 5252 ÷ RPM
Answer: TORQUE = 300 x 5252 ÷ 2700 = 584 lb-ft.
Example 2: How much TORQUE is required to produce 300 HP at 4600 RPM?
Answer: TORQUE = 300 x 5252 ÷ 4600 = 343 lb-ft.
Example 3: How much TORQUE is required to produce 300 HP at 8000 RPM?
Answer: TORQUE = 300 x 5252 ÷ 8000 = 197 lb-ft.
Example 4: How much TORQUE does the 41,000 RPM turbine section of a 300 HP gas turbine engine produce?
Answer: TORQUE = 300 x 5252 ÷ 41,000 = 38.4 lb-ft.
Example 5: The output shaft of the gearbox of the engine in Example 4 above turns at 1591 RPM. How much TORQUE is available on that shaft?
Answer: TORQUE = 300 x 5252 ÷ 1591 = 991 lb-ft.
(ignoring losses in the gearbox, of course).

 

[phil miller]

could it be torque intervention kicking in, that would give wavey graph i would of thought, who was it that mapped it in the southwest?

 

[Yohan87]

Did they dyno it with all 4 wheels spinning or in 2wd mode? If the former that would explain your wavey graph.

 

[beachbuggy]

could it be torque intervention kicking in, that would give wavey graph i would of thought, who was it that mapped it in the southwest?

Phil, you are almost certainly correct, wild timing oscillations will be the proof but you really need a high speed logger to do that. This assuming there isn't a hardware issue with something like the actuator allowing the wastegate to flap open

 

[ant schof]

Thanks everyone for replies so far . The dyno run was done in 2 wheel drive mode with the haldex fuse pulled , by celtic tuning , to be fair to them they have spent a number of hours mapping , even thouigh things are'nt quite right yet . On my second visit the car was scanned with Vagcom but no faults stored at all . Also to add i have replaced the air mass meter too , no change . I'm going to carry out a boost leak test today , what is cavitation ? and is there anyway i can test wastegate function in situ , many thanks ,

Ant

 

[badger5]

high initial boost in the rpm range you say it squeals is where the turbos intake is cavitating... 80mm TIP for the win

Your torque is boost driven and low in the rev range I would guess

Are you able to log anything with vcds?

blind poke and hoep resonces without data to look at

and you cant ignore the map may not be "optimised" from the equation

 

[ant schof]

Thanks for the reply Bill , whilst driving today aswell as the pitched squeal on boost after letting off the throttle i can hear a short feint scraping noise , possible turbine contact in the housing , i'm coming to the conclusion that my turbo's goosed . Now looking at replacing
with either a new or refurbed K04 . Think i'll take it back to be remapped once this is sorted and may well go for 80mm TIP in time