Sams Polo 3.0

**sambb** · 15-12-2020, 10:52 AM

woop I lied. Must have been looking at one I did in the wet with a soaked intercooler. Just checked again and on a dry run it topped inlet air temps at 29 degrees from a starting point of 21 on a 16-17 degree night. I'd pt the file on here but I cant seem to load/copy excel spreadsheets onto here.

**Sydneykid** · 15-12-2020, 10:56 AM

Originally Posted by sambb

woop I lied. Must have been looking at one I did in the wet with a soaked intercooler. Just checked again and on a dry run it topped inlet air temps at 29 degrees from a starting point of 21 on a 16-17 degree night. I'd pt the file on here but I cant seem to load/copy excel spreadsheets onto here.

That's more like it;

Assuming an intercooler efficiency of around 70% (an OK front mount) that means about 57degrees out of the compressor.
Assuming an intercooler efficiency of around 50% (an OK side mount) that means about 41 degrees out of the compressor.

Cheers
Gary

**h100vw** · 15-12-2020, 06:50 PM

Originally Posted by sambb

ah seems breathing mods a bit too good for the APR generic tune thats in the car. It runs stock injectors but with a 4 bar rather than 3 bar fuel pressure regulator. Right at around 3000-4000rpm which is the boost peak its pulling up to 6.5 degrees of timing and then as is usual for these things is conservative in taking it out again so its really robbing power. It was 17 degrees ambient and iAT stayed rock solid at 20 degrees throughout (same cant be said of the SEAT Sport IC coupled with the K03s). The tune is actually asking for 1.55 bar (22.5psi) and I'm only giving it 1.27 bar (18.4psi) yet the timing pull is happening. It looks like its going lean in that spot, where you least want it to. ie reaching 0.88-0.89 lambda, so I think its a fuelling issue. The duty cycle of the injectors in that spot (calculated online by entering rpm and injection ms into a calculator) came back at well under 70% so the injectors themsleves arent maxed at that point. The fuel pump is a virtually new uprated APS 265lph pump that was coping just fine on 550cc injectors at 3 bar (stock are 318cc) so I doubt I'm lacking fuel pressure behind those open times. Confirming this is that at the top end >6000rpm at 82% injector duty cycle its at 0.78 lambda.
So for some reason its going pretty lean at the top of the boost ramp which may be because it is moving much more air due to much less back pressure due to the mani and 3 inch dump/exhaust. But despite less boost? not sure. The overfuelling at the top end might be APR just covering off big EGT's or the fact that stock fuel pumps were probably struggling to keep up at that point and mine is doing just fine?
So it'll rocket up through the gears aok but when you do dyno style 3rd gear pulls from 2-2500rpm it exposes it. The timing pull can really be felt down low and the richness at the top is robbing it too because its no stronger there than the modded K03s was. So if I wanted to continue in the ghetto vane I could probably get some water meth into that lean spot with a boost trigger but I think not. Instead I'll chuck the EV14 550cc injectors back in with the 3 bar, maybe go from 2.5-2.75in MAF and get Dave Howlett to do some nefmoto magic on the tune.

I think the 4 BAR and stock MAF/injectors with software was a bit of a papering over the cracks exercise to keep the K04 conversion price down. No way it could run as good without bigger injectors and MAF.

I have no doubt it would be better with 3 BAR, 550s and a big MAF.

When a ported manifold can generate 20nm and 10kw everywhere over a stock one. Band aid fuelling must be holding it back

**sambb** · 15-12-2020, 08:23 PM

Yeah its a pretty shonky tune. So much requested boost, eg 1.5 bar, yet its lean as anything and pulling timing from the moment you plant your foot despite me capping the boost at only 18psi. I've gotten in contact with Dave so hopefully after xmas he'll be available to do something with it. I'll compression test it first just to make sure its worth dropping money on but yeah it needs a custom tune for sure.

**sambb** · 20-12-2020, 10:01 PM

some sydney north recommended lockdown viewing. The singular best F1 doco I've ever seen. Its from the 70's so has 'the death years' aspect to it but is like a time warp. Don't let the kids be watching at 33.30 or 1:17 or the credits even, as its pretty gut wrenching in places but its an unreal watch:

Documentary | Champions Forever (One by One) | The Formula One Drivers (1975) - English - YouTube

**seangti** · 23-12-2020, 03:16 PM

Hi Sam (and Gavin),
What turbo and manifold are you planning to run? You know how I always teeter on whether to tinker further or not, but considering a swap of turbo, which justifies removing the factory exhaust manifold for the extra power Gavin has referred to. I want an off the shelf turbo solution and perhaps just port the stock manifold, then retune. The alternative is to seek a retune as is to see where it's at...

**h100vw** · 23-12-2020, 04:54 PM

I'm going to fit a ported stock manifold over Christmas. I'll Dyno it before and after. Might get a tune up after to take advantage of extra flow I am expecting.
I also had a change of turbo back since the last tune which I haven't taken data for. So will grab logs for all runs.

**sambb** · 23-12-2020, 09:37 PM

Sean the current car was BW K04-001 (old stock type), 2.5 inch dump+ cat + back section with standard unported mani. When I say unported it seems to have been gasket matched at the flange but not ported where it counts eg runner cyl 3 and into the collector. The gasket matching of the runner openings I dont think would have achieved much because the exhaust ports in the head were untouched so oversizing the runner openings would only have created a step.
So first I went to my old cars 3 inch dump, 3 inch cat, step down to 2.75inch post cat and then UGP 2.5 inch back section. The boost (indicator of less back pressure) I was seeing went up from 21psi to nearly 23psi.
I then fitted up my old cars properly ported exhaust mani. It wasnt gasket matched but had porting where its needed. The boost basically was going over 25psi and sailing north. It'd have hit 30 psi for sure the speed at which the needle was going up. Didnt see where it got to because the foot came off the accelerator quick smart. I backed off the wastegate pre load from 3mm to a whisker below 2mm and there was no change. Was basically behaving like a turbo with a wastegate hose leak.
So while the bigger bore exhaust no doubt reduced back pressure, the ported mani had the grand daddy effect on back pressure (albeit in conjunction with the bigger dump) reduction and basically made the APR K04 tune unable to control boost. I've had to use a parrallel MBC to clip the boost peak down to sub 20psi and the car is way under fuelled so the extra air flow is undeniable. Basically you'll be able to either get the same power with less boost OR more power at the same boost OR if your turbo was underdone as it was, be able to turn up the boost without running it right off the comp map.

**sambb** · 23-12-2020, 10:21 PM

So credit where credits due, MCA fixed a couple of dramas with my rebuilt MCA's. They came back to me from their rebuild and re-valve with different base adjusters. On MCA's the base section, the spigot that fits into the hub receiver, is actually threaded onto the strut tube allowing for droop adjustment independent of ride height adjustment at the spring collar. So when I'd gotten them back the base adjusters weren't the old ones. They had new ones which turned out to be much shorter which altered the drop link flanges position. So MCA corrected all that and now they have flanges mounted on the tube centre line and positioned higher too. They look the goods, fit up aok and put the drop link right where it needs to be. Now that the Northern beaches are locked down my plan of going to wishbone mounted links will probably have to wait and at any rate I can run this way in the interum and they can be sold/transferred to any one elses car this way. A good redundancy to have.

So because the base adjusters were different lengths all my old measurements for positioning them for correct droop etc were null and void. I spent today fitting them up.
My MCA's have 100mm of shaft travel before bump stop contact. The bump stop itself is 17.5mm thick.
At my guard to ground ride height of 630mm I set the base adjusters up for 38mm shaft droop and 62mm shaft bump travel. That 38mm of shaft droop equated to approx 40mm wheel droop.
But there's a problem i'll need to sort. At ride height and the springs lined up so that the beginning of their free coils are in plain view I was able to measure what the spring travel until coil bind would be. If I measured and added up the air gaps, or measured and added up the coil thicknesses minus the total available length that the spring could travel, I get a measurement of 67mm.
That means the spring will be binding 67-62= only 5mm into the bump stop.
I know this means I need to increase the droop to limit shaft travel in bump but I'm not sure by how much.
What I'm thinking of doing is taking the 17.5mm bump stop and taking a 2/3rd measurement of that assuming that by the time its 2/3rds through its travel it is pretty much arrested anyway. That'd give approx 12mm. If I add this likely max of 12mm of bump stop travel to my 62mm of shaft travel then I could potentially travel 74mm in bump yes?
So if the spring coils will bind at 67mm of travel then I need to add 74-67 = 7mm of additional droop travel on the shaft to make sure that its 2/3rd into the bump stop before coil bind.
That'd give me 45mm shaft droop and 55mm shaft bump before bump stop contact. That seems to be the best compromise between not running excessive droop/limited bump travel, yet still giving a good safety margin RE protecting against coil bind.
I know I need to go to better thin wire springs that sag less at resting height. These ones are 11.68mm di wire and are preloaded to get the desired ride height which hurts things even more. At the moment I just need to get operational until I do that though.
What do you think viewers............Gary!!!....