The '2 ton bugswatter' - back for a gentle stroke

[Jonnybravo]

Nice results, the car must fly now !

[Jamo]

Ban posts like these, who else is now going to investigate head porting

[repo]

Was cam timing the same in both dyno runs?

What about compression ratio?

You mention You could not get more boost from stock head? What does it mean? You had 1,95 bar with stock head, how much with ported head?

[A80Avant]

i see.
tell us the boost on both setups, cause i have a non ported cyl head on mine with adu cams and just serviced(well about 60K kms ago) and i can get more power than the 450hp you got. That looks almost the same as my 3d gear pull but i do get more torque than 560Nm, and my boost starts at 2.0-2.1bar and holds until 6500+rpm then drops but i believe it has to do with the boost control rather than anything else.(hoping with vems new firmware to sort that out)

[shellah]

I see your project and I'm very impressed .You're living example of audimaniac
I'm waiting for the end of this

[AndyP]

Ban posts like these, who else is now going to investigate head porting

Why do you think I got mine done:mischeif: I dropped a new 7A head off with JP yesterday to replace the one that got destroyed. It's not going to be as radical as the head on his S6 but should still give good results.

[JP]

In answer to differences.

Both setups where identical in cam timing, intercooler, boost control, exhaust and intake manifold etc.

Other than the change in hotsides and cylinderheads everything on the car remained the same.

The cams themselves are of 7a origin that have been tweaked in their timing to each other which is shown in an earlier before and after on page 5. My decision on the cams was to optimize the 4500-7500rpm band for track day use without creating an undriveable daily. They do come in later than stock cams and definitely later than ADU cams.

The nature of the cam profile also means the turbo has to work harder to achieve boost so it becomes more difficult to sustain high boost pressures at high rpm. The .63 run was done at 2.15 bar holding to redline as opposed to the stock head with .82 housing that peaked at 1.95 dropping to 1.92bar at redline.

I'm using an apexi avcr and even maxing out the duty cycle and upping the boost Target we could not force it to exceed 1.95 on the dyno.

Again we tried to make the dyno runs similar by doing them both in 5th gear from around 1250-1300rpm with identical brake loading.

Now maybe the stock head produces more or less power than made and the same would apply to the ported version. Ultimately I don't really care what the real figures are as every dyno measures differently I'm more concerned with the comparison of before and after using the same means of measurement where possible to eliminate as many variables as possible.

Obviously more boost is going to make more power within reason. Which is why when the revised head is done it will be run at 1.95 to give direct comparison to the stock head. At the same boost pressures. Despite the fact the headwork allowed it to run more boost than stock is a separate issue. Hence it will also be run at 2.15 to see if any further gains are had with the new design and larger .82 hotside. Compared to the earlier .63 setup.

I may out of curiosity swap to a set of stock intake and 7a exhaust configuration to see how the curve changes and if no surge is experienced in higher gears (one reason for the greater overlap choice of 7a cams) I'll also try stock AAN cams. But I'll get to that at a later date.

Hopefully I've covered everything

[A80Avant]

so both runs are done on 5th gear pull? and it brings on the 0.82AR at 4000rpm? that is quite late! I suppose down to the 7A cams even tweaked.

very interesting results though!

what were the EGTs equally and what the AFR on both situations?

[JP]

AFR's where both in the same ball park. EGT's I don't know as I don't have a working probe at the moment .

[A80Avant]

since you have used the non ported head with the 0.82AR and had this result on 5th gear spool/highest torque, i must say that it should be all down to cams for it to be that different. Which means that ADU cams on a ported head should make things possibly closer to my liking as well!

[JP]

^^^ as a rule of thumb from personal experience the following rules apply.

Spool is affected by

a/r size of hotside
Weight of compressor wheel
Cam profile

Boost response aka lag is affected by

Internal volume of boost run/intercooler
Exhaust manifold design


Not to be confused by what headwork does.
Which is improve the actual efficiency of an engine. Which results in more torque/HP at a given rpm vs a given boost pressure. The end result being that in the lower rpm band the engine makes more power pulling it through the lower rev range quicker. When full boost is achieved it is delivering more of a punch. Then once in the higher rpm band it will carry on pulling as you can maintain a flat boost curve till redline assuming the compressor is capable of supplying the required airflow.

[A80Avant]

yes, indeed.

did a short run yesterday on 5th gear and i had 1.95bar @ 3600rpm and about 2.05bar at 3800rpm. That was though because on my current VEMS settings i dont bring boost too aggresively from 3000rpm as it spikes on 3d gear. I only have datalogs and not perfomance box data on that run, but i can say that the kick comes along with the amount of boost, so i presume the highest torque is somewhere near there. Surely though, specific headwork would be my next step (far future though as there is no more £££ atm). I would wait to see how much the whole picture is improved once you do the runs with the ported head and the 0.82AR

[Bram]

What else did you do on the cyl head? Must be more than porting-only, right? If not I would like you to port my 7A head

Boost profile and max output look very nice. Must be a dream to drive

[G60Rallye]

Nice to see you still developing this JP. It was seriously fast when you took me out in it!

[urS6Tom]

Sort of been really busy and sidetracked because of trying to juggle kids with work, but I've just pulled some pics of the camera.

Intercooler is a £60 job from ebay.





It required hacking out the back of the bumper to fit whilst retaining the aircon





The spec of the intercooler is a 300x450x75 ccore bar and plate with 63mm in and out.

Boost run consists of SFS hoses and their billet couplers for simplicity and is as follows

straight hose of turbo to 60mm dia with DV take of, billet coupler, 90 degree 60mm, billet coupler, 135 degree 60mm, intercooler, 45 degree 60mm, billet coupler, 90 degree 60mm.

This then brings it exactly to where the original sidemount intercooler exit was. From where I then fitted my MAF relocation contraption from earlier in the thread.

Hi - I'd like to do this mod to my S6 but can't find an intercooler on eBay in that size Don't suppose you can remember who you bought it from or have a link?

Also how would you recommend connecting the boost run to an RS2 turbo setup?

Cheers,
Tom