Bardman

I'm writing this post as I have recently come full circle, taking the car back to stock from initially having a tune and Cargraphic sports headers. Apologies for length, but I think its important to share the full story so people don’t jump to incorrect conclusions.

Firstly some background. I have had my car now for just over a year. It was purchased for street usage (its my daily driver) and has done a fair bit of that but still only around 8000km (approx. 5000 miles). Where I am currently living, there are a lot of 50km/hr (30 m/hr) zones on the daily commute and I was noticing a lot the 3.6krpm flat spot rowing the gears between 1,2,3. Driving through Winter also I had to keep my windows shut more often and felt the exhaust was a bit quiet with them closed.

So I figured the perfect solution was Sports Headers and a tune. Looking at what dyno charts were available, it seemed that headers were a great way to address the torque dip, and when combined with a tune you could achieve a really flat torque curve. Great! As my car is a street car I wasn’t really keen on catless headers, so I looked at the various catted (sports) headers that were available.

- Fabspeed
- Cargraphics
- FVD
- Dundon (although these were only a discussion at this point and potentially no catted option)

I wasn’t really happy with the Fabspeed dyno charts (it just seemed to push the dips higher up the range), and I couldn’t find any data on FVD. Dundon were discussing race headers only at that point, so I discounted them. So I ended up with Cargraphic sports headers and a tune from PP performance.

Initially I was really pleased, I had achieved exactly what I set out to do, flatter torque curve and a louder sound (I did have a problem with exhaust ‘burping’ due to too much gas pressure building up in the exhaust before the valves opened, but this was fixed with a revised tune). After a week or so of living with the car, however, I begun to fall out of love with the tune. Whilst the car pulled much stronger from very low in the rev range, it had lost some of its character and OEM feel. One of the real joys of the GT4 is the feeling when it lifts up “on its toes” at around 4.5k rpm, the transition is beautiful and was obviously the focus of quite some attention by the GT team. Whilst it still lifted at 4.5k, it didn’t all feel to synchronise in harmony (torque, power, induction, exhaust), leaving me a little dissatisfied. So I decided to remove the tune.

So with the catted headers and no tune, the car definitely had a better overall feel to it, but with time I started wondering about the sound of the car. Whilst at WOT it sounded great, at varying loads it just lacked a certain something, almost sounding pedestrian. There is a certain ‘serrated’ edge to the stock exhaust that is removed with the sports headers, which give a more constant note. Then I read this article, which talks about the work of Dr Bernhard Pfäfflin whose job it is to tune the exhaust note of Porsche cars. You can read it for yourselves, but this guy painstakingly builds up the desired sound of the car by tweaking header and exhaust properties until he gets exactly what he is after. He then has to play this sound back to the Porsche Board for them to approve it for production.

Here is the article: https://www.total911.com/perfecting-...w-911-carrera/

I guess I asked myself the question – who am I to mess with Bernhards work? A few weeks later I had refitted the stock headers and I am back in love with the car again. The rough feeling flat spot at 3.6k rpms is back again, but on balance I prefer the car like this, its an absolute gem.

tl;dr – the stock car is pretty close to perfect and that’s the way I’m keeping it!

golfnutintib

wait - u wanted midrange torque bump, w header/tune, you got it, and you're not happy cuz car didn't feel oem

well oem has sh*t happening 3.5-5k... i don't get what will actually make you happy... what am i missing????

Bardman

By not feeling OEM, I mean feeling OEM quality. The tune just felt like "max power" and was not sympathetic to the character of the car. There is a certain joy in wandering up and down the torque curve which I didn't fully appreciate until I took it away.

In short, modifying the car made me realise how much I like the stock car. I am happy now.

drwuss

Thanks for sharing your experience.

sho-one

are you selling your headers and/or tune?

Snowman.

He's in Australia so probably not your best option

If only I didn't have a set coming Brad I'd offer to take them off your hands. As a funny little side point which is kinda related to this principle - I've started running the Trofeo R's. They are amazing on track - but the grip level is so much higher than OEM that I find it's not as much fun on the road as it doesn't move around like it did on the OEM rubber. It just grips up everywhere (once the tyres are warm). It's making me consider a second set of wheels so I can go back to the OEM fun feel on the road - but still keep the Trofeo's for the track.

Buteo

Somewhat of an odd post, it seems to read as though you like the dip in power around 4.5krpm or so? You don't prefer a smoother and more broad power band?

GAZZ

Its a personal thing I suppose. Like buying a painting, you either like it or not.
At the end of the day, so long as YOU are happy...

For the GT4s character, you may want either street car or race car persona. Me, I prefer the dual nature of the beast and to be more race car like. Press this button or that and have the best of both worlds.

My GT4 has CG headers only and I think the upgrade is really nice and sounds less pedestrian now.
Then take my Cayman S which has more mods, its not excessive, but its so much better than stock in power, handling, sound, dynamics and many things are better than the GT4. But then GT4 does other things better like the gearbox and clutch, the power surge, the looks and liftoff soundtrack. I'm also glad they are not both the same.
Too bad the GT4 is a lot slower around the track (Dunlop Race Maxx) than the Cayman S (Yoko R specs).

Yellowbyrd

GAZZ, can you share with us what mods you have on your Cayman S that led to these improvements?

Mech33

Thanks for sharing! I've done similar 360's from stock to tuned back to stock on previous (non-Porsche) cars.

Regarding the tune, you can imagine that it's hard to get stock-like character and drivability when some 3rd party tuner is just hacking data tables or reverse engineered routines in such a complex engine control system. Sure, some peak numbers on a dyno chart might look better, but my opinion is that it is always in trade for something.

I'll be keeping my engine management stock on my car going forward.

GAZZ

Capristo headers + exhaust.
RSS LCAs, tie rods, drop links.
Spacers rear, Advan 18 wheels + Yoko A050 soft (30 profile rear for lower gearing).
Softronic kit: 82mm TB + Plenum etc.
Hi flo Air filter.
Semi solid transmission mounts.
Track alignment.
Factory options PCCB, PASM, LSD.

I still drive the car every few weeks and is mostly a track car now, its so good to drive . Still holds several track records too .
GT4 is the DD.

Bardman

Tune I had on a try before you buy basis but headers I may end of selling. As Snowman mentioned, however, I am in Australia so would really only make sense for a local buyer.

Yes, pity about timing, I thought about you guys doing the group buy, but I wanted to be 100% sure before I pulled the plug. Someone else may want them however, let me know if you are aware of anyone.

I guess it comes down to character. There is a certain pleasure in the slow build until you "pop the cork" at around 5k rpms when the car comes completely on song, blood quickening as this jagged / serrated exhaust plays in your ears. Some of this feeling went away with the headers (in particular the exhaust note didn't push my buttons in the same way) so on the whole I prefer stock to the car with headers. With regards to the tune, I remember when the Audi RS5 was launched at it was widely described as having no 'soul'. This is what the car felt like to me with the tune.

Agree - different things will please different people. I really wanted to like the headers, but ultimately I prefer the car without them.

Pretty much my thinking. Manufacturers have constraints such as fuel economy/emissions targets as well as marketing considerations (keeping the pecking order), but they have the massive advantage over tuning houses of being able to tweak the car from end to end until they have a combination that feels right. The costs for a tuning house to do the same when amortised over a small percentage of customers who have purchased a small number of units that a GT car gets produced in makes it very difficult for them to do likewise.

mrd_spy

how can one like the massive torque dip at 4.5k revs !!

very odd

yes you get a surgue at about 4.5k because the torque dipped so low so you get a feeling of the car picking up but the stock tune runs out of puff again at 6.5k so it not that fun to drive imo.

the Fabspeed dyno looks pants any way, they loose bhp higher up the range to get midrange torque you never see !! so a poor tune on a GT car.

but any tune which cleans up the dip at 4.5k and helps the car past 6.5k has to be a good thing.

Peter_GT4

Strange case here.

Maybe your tune wasn´t the best or it is only the combination with
IPD Plenum and 82mm TB that really makes the package work?

In my case with the above mentioned mods, I can only report the absolute opposite on
every issue you mentioned. And by no means the character of the engine is spoiled,
I find it a lot more charismatic and thrilling to drive now.

No matter what, good to hear you are happy now!

Peter

Leuz

I wonder if Dr Bernhard Pfäfflin has ever heard the sound of an STI idling....