Sam's build thread

[Sydneykid]

So if the whole super high EGT thing is really a function of restrictive exhaust manifolds and tiny turbos being pushed way too far out of their efficiency ranges, then hopefully it'll be a sweet thing with the better TFSI exhaust runners and a freer inlet. Even if it made just makes a conservative increase in grunt with the Golf 6 turbo but does it on a chunk less boost I'd be very happy.

High EGT is a result of a number of factors (not in any particular order);
1. High restriction on the exhaust side of the engine, too small an exhaust turbine/housing, too small exhaust valves/ports and/or manifold.
2. Too much boost for the compressor to produce efficiently (ie; out of its efficiency range).
3. This results in too high compressor outlet air temps.
4. Too small an intercooler to control the compressor outlet air temps.
5. High restriction on the inlet side of the engine, too small inlet valves/ports and/or manifold, pipework, throttle body etc.
6. Excessively retarded ignition timing made necessary by too high combustion pressures and/or too low an octane fuel.
7. It's a spiral effect, # 1 means you need more of #2, #5 means you need more of #2, more of #2 means you need more of #6 etc.

Without changing anything else you could lower the EGT dramatically by switching to E85, as it reduces the inlet air temps, lowers the combustion temperature and facilitates more ignition advance.


Cheers
Gary

[Sydneykid]

Alright I went down to check out the Escort again (which is now idling and revving like a motorbike) and spoke to my mate who's an SR20 tragic and showed him those flow numbers. He said if that is the case then yeah the small port flow figures definitely look choked on the inlet side relative to the exhaust. His suggestion since I already have a spare head was to take my good small port head off and get it flowed to get my own data. If the inlets are in fact the same as the exhaust and the numbers match that sheet, then he thought we could just bring out the small port to get it to flow the same ratio to exhaust as the large port head does. Not necessarily match large port flows but just get the inlet:exhaust flows making more sense. Then at least I'm left with a head that I know the history of too and is low kay.

What's his reasoning in going for the small port head? On a turbo engine I just haven't seen the logic in maintaining inlet airspeed with smaller ports. Whilst it's definitely beneficial in an N/A engine, it's next to irrelevant on a turbo engine with a compressor stuffing the ports full of air. All it does is increase the boost (via restrictions) required to make the same power.

FWIW, Nissan RB engines have exactly the reverse problem, too small exhaust valves and ports. Increase the exhaust valves by 1 mm and port to match and they make up to 50 hp more at the same boost.

Cheers
Gary

[metalhead]

Sam/Gary/anyone else - any recommendations for street usable track brake pads that will have reasonable rotor life (and preferably ok pad life)? I fitted Wilwood H pads with my new Wilwood front brakes earlier this year, and while I've been very happy with the performance (yes they dust a lot and squeel a bit, but I can live with that), they have chewed out the disks like crazy, I think I'll have to replace them after heading to Wakefield next week (they've done ~20 laps at Tamworth, ~20 laps at Wakefield, half a dozen hillclimbs and maybe 10,000 street km). Pads look barely worn! I really don't want to mess around with swapping pads every time I head to the track at this point if I can avoid it.

[Sydneykid]

Sam/Gary/anyone else - any recommendations for street usable track brake pads that will have reasonable rotor life (and preferably ok pad life)? I fitted Wilwood H pads with my new Wilwood front brakes earlier this year, and while I've been very happy with the performance (yes they dust a lot and squeel a bit, but I can live with that), they have chewed out the disks like crazy, I think I'll have to replace them after heading to Wakefield next week (they've done ~20 laps at Tamworth, ~20 laps at Wakefield, half a dozen hillclimbs and maybe 10,000 street km). Pads look barely worn! I really don't want to mess around with swapping pads every time I head to the track at this point if I can avoid it.

Are you using Wilwood rotors? I ask as there are dramatic differences in the metallurgy. In the Sprinter & the Civic we use their Spec37 curved vain rotors which last a couple of seasons, that's using Polymatrix A pads, a personal preference for the driver.

Polymatrix H is a pretty aggressive but long wearing compound, it's what we call an "endurance race" compound. It is supposed to last for a long time at high temperatures, so it's not surprising that they are hardly worn. If you prefer to stick with Wilwood I'd maybe give their BP10 or BP20 compounds a try. BP20 doesn't work at really low temperatures, so BP10 is probably the better choice for a road & track car and they will wear out faster than than Polymatix H's. But if you are doing long (track day) sessions then the BP20 is better at the sustained higher temperatures. Based on our experience I'd probably choose the Polymatrix A's over the BP20's.

Warning, not all Wilwood compounds are available to suite all Wilwood calipers, so do some homework first.

My personal preference is Hawk pads, we used the HP compound (used to be called High Performance Street) in my son's Evo which aside from their squeal (rather loud) were a pretty good combo pad, road and track. They now have a HP+ which is an improvement in all areas, but I have no experience with them. For myself (being far from the greatest braker), I like the Black's, it's a pretty forgiving compound with progressive bight and they are the lowest cost decent race pad (scrooge friendly). The next step up is HT10 which has a little more initial bight and as such requires a bit more sophistication from the driver in pedal control. A step up again is the DTC70, that's the pad I use in open wheelers (F3 etc) with down force, they have amazing bight, but need a pretty well controlled braking technique to avoid lock up. So maybe have a look at the HP+ or the Black compounds.

Plenty of choices, hopefully not too confusing.

Cheers
Gary

[metalhead]

Are you using Wilwood rotors? I ask as there are dramatic differences in the metallurgy. In the Sprinter & the Civic we use their Spec37 curved vain rotors which last a couple of seasons, that's using Polymatrix A pads, a personal preference for the driver.

Yes, Wilwood rotors. They are a "GT 72 Curved Vane Rotor", part numbers 160-8398 and 160-8399. Are they good or is there something better that I should be looking at? They're not exactly cheap. I'm not sure how to cross-reference them to look for other options.

Polymatrix H is a pretty aggressive but long wearing compound, it's what we call an "endurance race" compound. It is supposed to last for a long time at high temperatures, so it's not surprising that they are hardly worn. If you prefer to stick with Wilwood I'd maybe give their BP10 or BP20 compounds a try. BP20 doesn't work at really low temperatures, so BP10 is probably the better choice for a road & track car and they will wear out faster than than Polymatix H's. But if you are doing long (track day) sessions then the BP20 is better at the sustained higher temperatures. Based on our experience I'd probably choose the Polymatrix A's over the BP20's.

Warning, not all Wilwood compounds are available to suite all Wilwood calipers, so do some homework first.

My personal preference is Hawk pads, we used the HP compound (used to be called High Performance Street) in my son's Evo which aside from their squeal (rather loud) were a pretty good combo pad, road and track. They now have a HP+ which is an improvement in all areas, but I have no experience with them. For myself (being far from the greatest braker), I like the Black's, it's a pretty forgiving compound with progressive bight and they are the lowest cost decent race pad (scrooge friendly). The next step up is HT10 which has a little more initial bight and as such requires a bit more sophistication from the driver in pedal control. A step up again is the DTC70, that's the pad I use in open wheelers (F3 etc) with down force, they have amazing bight, but need a pretty well controlled braking technique to avoid lock up. So maybe have a look at the HP+ or the Black compounds.

Plenty of choices, hopefully not too confusing.

Cheers
Gary

OK, thanks. The rotors are pretty expensive so I'd prefer to chew pads if I'm going to go through one or the other quickly! I don't mind noise, dust, and a bit of extra effort required when cold, if it still works ok and will hold up better on the track. I actually have a set of BP10 pads that came with the kit, but the seller told me they were no good for track use so I didn't even bother fitting them. Would they be worth trying or am I just going to cook them after a couple of laps? I don't really care about staying with the same brand, I have Carbotech xp8s in the factory rear calipers, and had their xp10s in the factory front calipers. I find it hard to cross reference pads between brands, the pads are backing plate 7416 which have all the Wilwood compounds you mentioned available and a couple of others. Where can I find which Hawk pads will fit/suit?

Thanks heaps for your detailed response!

[metalhead]

The rotors say they are the Spec37 metallurgy.

Are these the appropriate Hawk pads?: Hawk Brake Pad, Wilwood Superlite Bridge Bolt - Pegasus Auto Racing Supplies

[sambb]

No he wanted me to port what I've got (the spare small port head) simply because I have one rather than tracking down a second hand large port that might be shagged. We were going to look into CNC programmes to do the bulk of the work and then he'd finish it off but...…..
Well its all a moot point now because I just got my hands on a brand new large port fully assembled head. It was bought by Brian at Gti Imports from a wollongong VW dealership where it had been on their shelf. They were clearing old stock so he bought two of them. Its complete with valve train, cams etc etc still in its blue plastic. And I got it for a song so super happy.
There will be still money to spend because
1. I'm not sure about stem seals. Do they dry up when sat on a shelf for a long period of time? Also the hydraulic lifters - what happens to them when they've never sucked oil and sit there under pressure dry for so long?
2. The Golf 4 Gti large port head didnt have VCT. So it has a fixed chain bewteen the exhaust and inlet camshaft. Now I can definitely run it like that as based on those logs I'd done before, the Polo runs (other than at cold start) as a fixed timing head. So the choice is do I just run it as is or go to the effort of fitting the VCT tensioner from later cars so that I have the capability to tune the inlet cam if large port does turn out to be a bit doughy with the bigger turbo down low. I'm sure I read somewhere that the fixed timing heads had the inlet cam set 4 degrees advanced compared to where its set in the VCT cars ie the VCT cars can run the cam 10 degrees advanced through the torque hump and when they set back to their retarded 'zero' position, that position is not the same as the non VCT inlet cam position. Now I don't know if this is true of any 20V head fitted with VCT or if its only true of VCT heads that actually use the VCT on the fly (not just at start up) eg Audi's, so i'll have to do a bit more research on that. But if I run it fixed with no VCT then I still have the capability with my adjustable cam shaft pulley to advance and retard both cams to find a relative/compromise sweet spot. Maybe that'll be all I need.
either way. Fat port head in my garage, already built, could just be bolted down. I think I shall go and get a beer and ogle it!

[metalhead]

Score!

[simon k]

score indeed!

[sambb]

lining up rods and pistons as we speak. Defo no money left over for tyres now..... maybe a pair of secondies at best

I want to sort a baffled sump for this engine so I might pull the sump off the spare 90,000km motor and take the main caps off and have a look at the main bearings. If they look totally schmick I'll start to weigh up if it'll be a more in depth build or just a hone, re ring/rod/piston, , put the mains back on with ARP's and then get the head on. Last thing I want is a drawn out build. Lifes to short