Sams Polo 3.0

[sambb]

[sambb]

MIA engines built bottom end:

- forged X-beam rods ( 20mm wrist pin, forced pin oiled), rods weighed in exactly the same and balanced. Crank balanced, ARP 2000 conrod bolts, Audi S3 pistons ceramic coated skirts and dome, Special Piston Services ring set, factory mains bolts, factory main/conrod bearings. Came from MIA with my modified door-baffled sump fitted.

- head AEB large port bought brand new from Brian at GTI imports. Converted to run VVT with addition of BJX tensioner (new sliders) and cam angle sensor. Supertech stainless steel exhaust valves, inc brand new cams, hydraulic buckets etc etc. ARP 2000 head bolts. Factory MLS head gasket. Head assembly, fitting, timing done by me.

- cam timing: Cat Cams adjsutable timing pulley, manual belt tensioner SKF off 1.8 KR engines (same as IE kit) , IE dampener/tensioner delete plate with idler. Adjustable cam pulley may or may not be warranted from a timing standpoint as this engine will be running active VVT like Audi S3's. If cam timing not at 0 degrees in VagCom in its VVT retarded position then the pulley can be adjusted to create that condition. Also much stronger than the std sintered pulley.

[sambb]

These were some previous pics of the bottom ends fun bits

[pogopins]

looking great! what kind of power/torque figures are you aiming at now?

[sambb]

No idea to be honest. It'll most likely go back in with the current TFSI turbo out of the Golf MK6 Gti in it. On the current motor that turbo isn't maxxed and is also running fixed cam timing as more torque down low from VVT might have been a little risky. On this new motor with allegedly slightly less compression from the S3 pistons (9.25 vs 9.5:1), large port head and active VVT and not really any consideration paid to rod preservation - it'll be a bit rowdier I'd say. In terms of numbers, it'll just be what it is when the tuning is finished. Because it doesn't get tuned on one, there's no reason to put it on a dyno other than to get a figure. I'll only be able to get a guesstimate of power from the airflow numbers through the MAF in the logs but they relate to a crank figure and only give you a ball park anyway. The top end might be a little better due to the large port breathing easier but at the end of the day its still built around the same cams. I didn't want to rev higher because then I was going to have to do valve springs, retainers, inlet valves. So top end power will probably improve a bit, but where I expect (and dearly hope for) legit gains will be in the 3800-5800rpm range. I reckon the current motor could be 265hp peak at the crank. I just want more torque higher up even if it barely cracks 280, that'd be unreal.

[Trubs]

so there's been a bit of action on the blue Polo latel. Some of it welcome and long overdue, others far from welcome.

FULL REAR BEAM SWAP

A few things prompted this. The blue car came with Audi TT vented rear discs and calipers. I've been pretty unconvinced of their necessity to be honest. For the extra pretty significant weight they add to the unsprung mass I'm just not sure they are even required. I had reshimmed the bean so that it was running similar geometry to the beam on my silver car, so suspension setup was more or less equivalent. Despite that it just felt heavy and lumbersome, didnt ride bumps well causing the ESP and ABS to jump in at bad bad times eg over rumble strips where it never did that on the other car. While they may have operated cooler due to the venting, the calipers were a fair bit bigger/heavier, yet the pad size was identical between the stock rear brakes and these.

I was looking at getting a full set of 8L S3 Quattro brakes (with the vented rears like yours) but didn’t realise there would be issues like you are having. Would you just recommend changing the fronts out? Also wonder if there would be an imbalance with the bigger fronts and stock rears.

[h100vw]

I was looking at getting a full set of 8L S3 Quattro brakes (with the vented rears like yours) but didn’t realise there would be issues like you are having. Would you just recommend changing the fronts out? Also wonder if there would be an imbalance with the bigger fronts and stock rears.

You can run bigger fronts on their own if you want. An upgrade to the master cylinder makes the best of them. There's not a massive imbalance for the street.

[Trubs]

You can run bigger fronts on their own if you want. An upgrade to the master cylinder makes the best of them. There's not a massive imbalance for the street.

Be mostly used for the street, wanting to do an occasional track day.
What upgrades to the master cylinder need to be done to get the most from it?

[sambb]

Hi mate. sorry, just saw your post. If you are just running on the street with occasional track days I wouldn't bother doing the bigger vented rears. They are simply not needed. When I mentioned what I didn't like about them, we are talking driving it on its limit on semi slicks going for every last tenth of lap or hillclimb time. Not issues you are ever going to get even 20% towards on the street. On the street they just simply add weight. The pad is the same size so you are just carrying around venting that isn't necessary, extra disc weight and more caliper weight. Yeah they may clamp slightly further outward on a bigger diameter disc, but you won't feel that as the braking is so heavily biased towards the front anyway. If you are doing supersprints going full send for 8 laps you may notice more lingevity but to me I felt the weight penalty more than any braking advantage. Do the fronts yes, but only do the rears if you have your heart set on it.
A bigger master cylinder definitely gives you a shorter pedal throw. I did that mod to get away from the long sinky pedal you get on the stock master cylinder. To be honest I'm not sold on it though. The stock booster is just so huge that in my opinion the new combination is now overboosted. In nippy street driving its too grabby to heel and toe and even when you are really going for it its made it significantly harder to heel and toe smoothly because you need hardly any leg pressure to brake.
For street and sometime track day stuff I'd say just do the fronts, leave the rest as is (you can get DBA T2 slotted rears) and spend your coin on pads and good fluid. Have a track set of pads (bedded in and ready to go - even just fronts would be ok) that you instal for track days, and standard sort of pad for street duties. If I had my Polo time again that'd have covered 95% of everything I ever needed for street, track day and comp.

[Trubs]

Hi mate. sorry, just saw your post. If you are just running on the street with occasional track days I wouldn't bother doing the bigger vented rears. They are simply not needed. When I mentioned what I didn't like about them, we are talking driving it on its limit on semi slicks going for every last tenth of lap or hillclimb time. Not issues you are ever going to get even 20% towards on the street. On the street they just simply add weight. The pad is the same size so you are just carrying around venting that isn't necessary, extra disc weight and more caliper weight. Yeah they may clamp slightly further outward on a bigger diameter disc, but you won't feel that as the braking is so heavily biased towards the front anyway. If you are doing supersprints going full send for 8 laps you may notice more lingevity but to me I felt the weight penalty more than any braking advantage. Do the fronts yes, but only do the rears if you have your heart set on it.
A bigger master cylinder definitely gives you a shorter pedal throw. I did that mod to get away from the long sinky pedal you get on the stock master cylinder. To be honest I'm not sold on it though. The stock booster is just so huge that in my opinion the new combination is now overboosted. In nippy street driving its too grabby to heel and toe and even when you are really going for it its made it significantly harder to heel and toe smoothly because you need hardly any leg pressure to brake.
For street and sometime track day stuff I'd say just do the fronts, leave the rest as is (you can get DBA T2 slotted rears) and spend your coin on pads and good fluid. Have a track set of pads (bedded in and ready to go - even just fronts would be ok) that you instal for track days, and standard sort of pad for street duties. If I had my Polo time again that'd have covered 95% of everything I ever needed for street, track day and comp.

Cheers for explaining. What exactly is the brake booster mod?

Will probably end up just doing the fronts but I’m kinda torn between doing the rears, I’ve got a cup edition with the 17” wheels and I feel like it would be aesthetically pleasing having the bigger rear brakes filling up the wheel.
Here in NZ I have only found 1 8L S3 Quattro getting wrecked and the guy wanted over a grand just for set of 4 calipers and carries. So just doing the fronts will end up easier on the wallet.