rs32 Posted September 22, 2006 Report Share Posted September 22, 2006 those who read this forum regularly will have seen me posting various details of efforts to tune my MkV R32 using the widely accepted route of exhaust part upgrades and ECU remapping. Recent weeks have been a real eye-opener for me and I've been fortunate enough to learn a huge amount. Now I'm not going to encourage a debate about rolling road accuracy, opinions on certain tuners or specific horsepower figures. However I believe I have some interesting info to report from recent efforts. I originally ran the car with a Milltek cat-back exhaust and no remap. At 6k miles the car was dyno'd and it produced figures that I was happy with for the mileage and exhaust upgrade. We'll call these figures the "baseline". At 9k miles I had an initial remap applied to the car. The car was not dyno'd at this point, but felt very strong and this gave me confidence to consider further options. At 12k miles I had Milltek Manifolds, Sports Cats and a suitable remap added, then the car was dyno'd again after a few hundred miles. At this point the readings were a 4% power loss and a 13% torque loss when compared to the baseline. This was confusing to say the least. Further investigations led me to the discussion about back-pressure and we established evidence suggesting that reduced back-pressure means less torque. The conclusion was that this was caused by the upgraded manifolds. So the manifolds came off, leaving the Milltek manifold-back system and the appropriate remap. At 14k miles the car was dyno'd again, showing a negligible power increase (1 bhp) and a torque loss of 8% when compared to the baseline. So at least I have my original horsepower figure back again, however there is still a loss of peak torque. I also have a flat-spot at around 2k revs that definitely did not exist at 9k miles (this was only apparent after the manifolds/cats were added so I am happy this is not down to having a remap). All the dyno runs were done at the same place, on what seems to be regarded as good quality equipment, there were slight variations in temperature and humidity between the runs for info. Would appreciate your thoughts on these details. I am considering removing the cats to see if the flat-spot goes, putting the car back to "the baseline" situation. Link to comment Share on other sites More sharing options...
goodboy1451 Posted September 22, 2006 Report Share Posted September 22, 2006 I really enjoyed reading your postings about your experiments. Thank you so much for sharing your explorations. I am sorry to hear that the SChrick manifold didn't perform up to par. I must say my hopes that this could be the next potential upgrade were dashed. Regarding your present torque performance, could it be due to your car engine ECU need some time to relearn with the new setup ?? Link to comment Share on other sites More sharing options...
AGK512 Posted September 22, 2006 Report Share Posted September 22, 2006 Nothing ventured nothing gained eh Rich. Sounds like your getting things back on track again which is good to hear Very interestng and balanced post. Hope it hasn't dented the wallet too much ! Would you venture an estimate on the miltek back box increase over standard is I assume a nominal 5-10hp ? Wich by the sounds of it is what you will end up running in the short term ? Cheers Link to comment Share on other sites More sharing options...
rs32 Posted September 22, 2006 Author Report Share Posted September 22, 2006 based on these limited findings I would venture that the cat-back exhaust (and possibly ECU remap) is the 'best' option unless internal engine mods are planned. because nothing has been bench tested this is of course only relevant to my car/results so far. Link to comment Share on other sites More sharing options...
vindaloo Posted September 22, 2006 Report Share Posted September 22, 2006 Rich... your well informed comments and observations are absolutely invaluable to all of us MKV owners who are seriously contemplating upgrading our babies. My conclusions at the moment due very largely to you help point me in the direction of no engine/remap or exhaust changes but a Haldex upgrade & hopefully a Koni FSD install (if they ever produce a kit for our cars). Thank you once gain for sharing this incredibly useful info with us all Link to comment Share on other sites More sharing options...
ChrisBuer Posted September 22, 2006 Report Share Posted September 22, 2006 Yeah good work Rich! I was originally tempted with the manifold and sports cats but at a quoted £1400, I decided against it. Keep us up to date with any more developments and hopefully we'll all get to meet at the "Biggest R Meet Ever" Cheers! Link to comment Share on other sites More sharing options...
UKLooney Posted September 23, 2006 Report Share Posted September 23, 2006 Cheers Rich, Your an invaluable member of the community Link to comment Share on other sites More sharing options...
khutula Posted September 24, 2006 Report Share Posted September 24, 2006 [ QUOTE ] I am considering removing the cats to see if the flat-spot goes, putting the car back to "the baseline" situation. [/ QUOTE ] Have you spoken to Milltek about this at all? I really want the cats fitted to my MKIV but your detailed reports are making me think twice. Very comprehensive posts Link to comment Share on other sites More sharing options...
rs32 Posted September 25, 2006 Author Report Share Posted September 25, 2006 [ QUOTE ] [ QUOTE ] I am considering removing the cats to see if the flat-spot goes, putting the car back to "the baseline" situation. [/ QUOTE ] Have you spoken to Milltek about this at all? I really want the cats fitted to my MKIV but your detailed reports are making me think twice. [/ QUOTE ] As I have said elsewhere these findings cannot necessarily apply to the MkIV - there are many owners on here who have this mod and who have established gains from the cats according to their dyno results. Also worth pointing out that I'm not working with the tuners based on dyno numbers alone - the driveability of the car is also taken into account at each stage. The problem I've been suffering from is that the initial behaviour of the car when the mods were done seemed very impressive (esp at higher revs). It's only after driving around 1k miles since the mods that the full behaviour became clear. When you road-test a car after having a tuning-related mod done, the tendency is to bury the accelerator pedal rather than drive in the normal way - so any issues have taken a while to become apparent. Note that the tuners are being very responsive to any feedback I'm giving them, and I'm confident we'll get things running smoothly with a bit more effort. I thought it important to differentiate between the feeling of improvements and the actual behaviour by using my dyno results as a guide. khutula - try the cats and see what they do for your car. Link to comment Share on other sites More sharing options...
Dan32 Posted September 25, 2006 Report Share Posted September 25, 2006 Speaking from the MKIV point of view, my car with cats now seems to run very well, with no loss of torque or top end pull. As Rich has been keen to point out, the dyno figures are just one aspect of what he has done to test the new parts, buts its the feel of the car which is the most important. In his case, the loss of torque was evident when driving which takes away from the driveability whereas my car (and I should think most other similarly modded MKIVs) feels stronger due to the cats. Maybe the MKIV is not so dependant on back pressure to create torque as the MKV seems to be, although I have heard that the MKIV will suffer as a result of putting on any sort of sports manifold. Link to comment Share on other sites More sharing options...
khutula Posted September 26, 2006 Report Share Posted September 26, 2006 [ QUOTE ] khutula - try the cats and see what they do for your car. [/ QUOTE ] I will get them done in the next month or so, and then I will get the Revo Stage 2 remap I haven't had my car dyno'd ever so I can't use science to judge my car, all I know that at the moment it drives brilliantly and I am very very happy with it. Adding the CAI recently made it over smoother allround and seems to pull more. Adding the newly launched V-Power has made it even better. I can only imagine the cats will improve it even more. I just need to find a way of getting it done without the other half finding out Link to comment Share on other sites More sharing options...
RedRobin Posted September 26, 2006 Report Share Posted September 26, 2006 Dyno's aren't an exact science anyway. Apparently they can fluctuate according to all sorts of factors and they can also vary from one dyno to another. However, they can be a guide. Link to comment Share on other sites More sharing options...
Oatz Posted September 26, 2006 Report Share Posted September 26, 2006 from my experience you should take dyno readings with a huge pinch of salt Link to comment Share on other sites More sharing options...
rs32 Posted September 26, 2006 Author Report Share Posted September 26, 2006 agree completely that dyno results cannot be the only measure of performance. What they have done for me in this case is to back up the objective appraisal of how the car feels. This is the key point - until I had chance to assess the performance without the excitement of a new mod being fitted I did not realise the extent of the apparent losses. The dyno runs have given very linear results - and I'm happy that they show the true picture of how the car has driven at each stage - although I feel slightly stupid that I didn't detect the losses straight away. The mind plays tricks it would seem, especially when that sweet Milltek music is bellowing away Link to comment Share on other sites More sharing options...
rs32 Posted September 26, 2006 Author Report Share Posted September 26, 2006 also worth pointing out that I'm getting good support from the companies involved more to follow hopefully in the next few days.... Link to comment Share on other sites More sharing options...
rs32 Posted September 28, 2006 Author Report Share Posted September 28, 2006 can I ask a favour from MkIV owners - have any of you with the stage 2 upgrade (cats + cat back + stage 2 remap) encountered a flat spot at around 2k rpm and found this to be caused by a failing MAF sensor ? The MAF on the MkV is made by Siemens rather than Bosch but I am suspicious of its behaviour as there are also other signs of mine not being quite right. The plan is to 1. swap MAF to see if cats + stage 2 map then behave themselves 2. revert to stage 1 map to prove that the software is not at fault 3. revert to standard cats - hoping this is isn't needed as the cats reduce the exhaust boominess at around 2.5k rpm Link to comment Share on other sites More sharing options...
chiller Posted October 1, 2006 Report Share Posted October 1, 2006 Great discussion,but could someone tell me what a remap alone did in upping the bhp. Link to comment Share on other sites More sharing options...
petsy Posted October 1, 2006 Report Share Posted October 1, 2006 very little I suspect as the R32 has a N/A engine. Link to comment Share on other sites More sharing options...
Mook Posted October 2, 2006 Report Share Posted October 2, 2006 [ QUOTE ] Great discussion,but could someone tell me what a remap alone did in upping the bhp. [/ QUOTE ] On the original (i.e. when they first came out) Mk4 R32, a remap would take the car from 237 bhp to 247 bhp. When VW released the #6463 ECU update, this gave the car 247 bhp (250PS), because they readjusted the fuelling and timing with the ECU update. If you apply a remap to a post #6463 update Mk4 R32, you should expect to get up to 252 bhp. If you're running a Mk5 R32 with 250PS (247bhp), you would expect to gain about 10 bhp, taking it up to around 257 bhp. Details on the AmD site at http://www.amdtechnik.com/products.variant.cfm?variantid=351 AutoPS site at http://www.autops.co.uk/news.php or you can dig some on the REVO site at www.revotechnik.com HTH Link to comment Share on other sites More sharing options...
rs32 Posted October 2, 2006 Author Report Share Posted October 2, 2006 ... bear in mind that some of the earlier Mk5's were showing around 230 bhp when new - only rising to the 250 mark at around 10k miles. should have some more comparison results later this week if all goes well. Link to comment Share on other sites More sharing options...
rs32 Posted October 6, 2006 Author Report Share Posted October 6, 2006 right then, some good news and some bad news. the good news first. I have spent another day at APS and we followed our plan for isolating the loss of torque. Firstly a revised remap was applied to the car to see whether retarding the ignition timing slightly at lower revs sorted out the flat spot, and very minor adjustments to fuelling. This made the car slightly stronger for mid/top end but did not cure the flat spot. So the cats came off and the original remap was applied. RESULT As soon as I started the test drive I knew things were good. This time around I tried really hard to test the whole rev range in different circumstances - the flat spot had definitely gone and the torque-surge was very strong. So what I have now is my setup from 12k miles but with an extra 2.5k on the clock. After 80 miles of my journey home the road opened up and it feels even better than before - purely the benefits of an extra few miles, no doubt the previous lack of torque also makes it feel much better now. Am very happy with the car and yet another superb effort by the APS team - they are also happy that the car is back to normal and our development efforts have been worthwhile, if only to prove a point. So on to the bad news. These findings potentially mean there is no point fitting the sports cats to the MkV unless you are prepared to live with the trade-off between a boomy exhaust (when very hot) and a loss of torque. We seem to have proved that on this model of .:R the cats degrade the performance even though they help the sound. I would expect the behaviour of the full exhaust system to be different if the Shrick cam upgrade is done, but I cannot recommend (based on my car and the documented experiences) the Milltek Manifolds/Cats combination on a MkV R32 with a remap. The car will be dyno'd again soon to close off the experiment - I trust this is useful to those who may be thinking about upgrades. It's great having my car 'back' again Link to comment Share on other sites More sharing options...
RedRobin Posted October 6, 2006 Report Share Posted October 6, 2006 to rs32. I think that an awful lot of people owe you a drink for both your work and your articulate reporting. Link to comment Share on other sites More sharing options...
vindaloo Posted October 6, 2006 Report Share Posted October 6, 2006 [ QUOTE ] to rs32. I think that an awful lot of people owe you a drink for both your work and your articulate reporting. [/ QUOTE ] I couldn't agree more Link to comment Share on other sites More sharing options...
jimmyp Posted October 7, 2006 Report Share Posted October 7, 2006 Good effort rs32... Link to comment Share on other sites More sharing options...
ChrisBuer Posted October 7, 2006 Report Share Posted October 7, 2006 Ah so you were the chap out on test drive when I phoned Ed Good news your car is back to her old self now Rich! I'll also echo the sentiments of others on the board and say thanks for all of your posts. They are not only interesting but very useful for us "budding modders" Link to comment Share on other sites More sharing options...
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