Sam's build thread

[Sydneykid]

In Dunlops they have 4 compounds - S (wet for very light cars), M (wet) , R (sprint races & light cars) and H (long distance races & heavy cars). I think the 205/50/15 D03G in the R compound would suite your car very well, they are similar to Medium compound in the A050's.

On the Sprinter (you've seen it) we run 215/50/15's on 7" rims. Some of the guys run 225/50/15 on 7's but I think they are too baggy. Can you fit 215/50/15's on the Polo? I might be able to find a 2nd hand pair/set of A050 Mediums.


Cheers
Gary

[sambb]

Yeah it appears that 215/50/15 will fit. I run 15mm front spacers so that can be paired back to 10mm if the guard becomes an issue. I've got my taller 200mm springs now too (to sort that coil bind - lack of bump travel issue) and when they go in i'll raise the front even more, so 215's should be ok. If you happen to find second hand 215's that would be absolutely brilliant as I've been trying for ages to source some second hand and can only ever find ones that are 4 years old etc.

Was IPRA on the weekend?

[metalhead]

MY MATES AR-1 TEST: So my mate was out at the Eastern Ck south circuit today with the Renault car club testing a new set of Nankang AR-1's. He has two sets of Rega's and so had a very fresh set of same size 195/50/15 Yoko A050 mediums on hand to compare them to. The Yokos had been oven baked by Gordon Leven and had done only two 7-9 lap sessions at Wakefield when we were there in January (22-25 degree day though). The Nankangs were bought new 2 weeks ago (late 2017 build) and he'd done a street scrub on them a day and a half before the event. He said based on finger nail duro test they were softer than his Yoko mediums. Today was about 26 degrees on the coast so could have been nudging 30 degrees at the track I'm guessing.
His car is a W172 renault Clio 2 litre atmo. Standard 4 into 1, W182 inlet manifold, W182 cams with some cam timing changes and a plug and play aftermarket ECU. It has nearly 160hp at the wheels but wouldnt have our low rpm torque. Car is road registered engineered 2 seater with 4 point cage. 6kg front and rear springs. Stock front bar, big rear bar. Toe out everywhere, 3 degree front neg, 2 degree rear neg and roll centre/steer correction kits. weighs 1050kg with 1/4 tank, no driver. Rear beam, mac strut setup just like ours and close in weight.
He said his first session was taken easy so that he could sight the track and get the tyres up to temp and see how they were going with pressures etc. He said he then did the next three sessions and really struggled with the car. He said he was fighting the car struggling to get it turned in, despite the quaife he was getting straight linepower on wheelspin out of the slower corners and found that the car was sliding laterally a lot. He said he actually wasnt enjoying himself and was wondering whether it was because he was on a new track and was getting the lines wrong, or if it was the stiffer 6kg/mm springs that we'd put in the back. He said he could feel them go off a bit to in the later sessions. Not sure if that was pressure related - forgot to ask. He said he tried 32psi hot, 34 psi hot, 30psi hot and came in on one session and set them to 29 psi front 31psi rear to see if that would help get the thing turned in. Throughout all this he said his times were all within 5/10th of 1:09.50's.
So in the last session he thought he'd go out on the Yokos. They were stone cold so he set the fronts at 24 psi cold and rears at 27psi and he said immediately it was like they were an old friend. The car was balanced sharp and doing what he told it. He said his laps for that last session considering also that he was coming up from stone cold low pressures were same deal all within 5/10ths of one another but 2 SECONDS quicker - all around 1:07.5's.
Glad he was the guinea pig because I was going to do it myself, so its a bummer that a nice cheap semi that had had good reports on small cars doesnt seem to hold a candle to the Yokos', and a double bummer that it seems to be that once again you get what you pay for and pay for Yokos you surely do! Whether any of this holds true for bigger cars I dont know but as a good basis for comparison against our car. He said they are still better than his 'street semi' Yoko AD08R's would have been, but markedly off the Yoko's. They'll be on gumtree if you want em cheap!

Wow... That's a bummer for me! In examining my in car videos of my performance at Canberra the other weekend, I was fairly confident that the Nankangs were quite a bit quicker than my street Continental ExtremeContact Sports (which are an excellent street tyre, quicker than Michelin Pilot Supersports), but again it was hard to tell in poor weather on an unfamiliar track. My brother has also recently run them on his mx5 in some supersprints and gone a decent amount quicker than he has previously on Dunlop StarSpecs - again a great street/track tyre but not an R spec. Definitely didn't notice any issues with turn in on my car, but my car tends to be very good there anyway. Very interesting!

I had a chat to James Pearson at Canberra about them too actually, as he had them on his very quick rx7. He said he thought they were ok, not the best he's used but good for the price.

So yeh, maybe not up to some of the reviews we were reading early on. Good for the money perhaps, depending on the car, though sounds like they didn't work well on the Clio.

[Sydneykid]

Yeah it appears that 215/50/15 will fit. I run 15mm front spacers so that can be paired back to 10mm if the guard becomes an issue. I've got my taller 200mm springs now too (to sort that coil bind - lack of bump travel issue) and when they go in i'll raise the front even more, so 215's should be ok. If you happen to find second hand 215's that would be absolutely brilliant as I've been trying for ages to source some second hand and can only ever find ones that are 4 years old etc.

Was IPRA on the weekend?

Round 2, next weekend at Eastern Creek, race engine rebuilt from rocker failure, installed it last Saturday and we'll run it in on Friday. Hopefully not having to come from rear of grid to 4th with a standard engine this Round. Driver is getting a tiny bit disheartened, need to get him on the podium to spray some champagne.

I'll ask around about the 215's and check the workshop, there might be some. The problem with A050's is that they are pretty good until bald, so people don't tend to change them while they have any life left.


Cheers
Gary

[sambb]

Don't worry Andrew. From what he said they'd absolutely kick his street semis (and AD08R's are pretty damn good tyres) and they were better than a second hand set of Toyo R1-RR that he'd run in the early sessions at Wakefield. Just not up to the A050's. It think amongst those tyres for sprints that the yoko's are the kind of tyre that you don't want to try unless you are certain you can afford them in the future because the others just aren't quite as good and there's no going back. The only reason I ever had that set of softs that I've been running at the hillclimbs was because I found a dodgy grey importer who was selling them CHEAP. Wouldn't have run 55 profile if they weren't only 125 bucks each! But there's no such off the back of a truck deals on them that I can see at the moment. Unfortunately my mediums are basically done (should be enough to get me through at DubNats and that's it) and the softs are pretty mutilated. So it'll be mediums from now on. Hopefully provided I'm putting 215 vs 195 width rubber onto the road, the mediums should be ok for the hillclimbs. All up though, you'll be much much quicker on the AR-1's than street tyres.

not R1R's sorry R888RR's which are definitely an R spec

[sambb]

The car is going to get changed over to different hardware and a tune very soon - hopefully sorted by VWNats, so I thought I'd just show how I've been running around lately. Going back a bit I realised I was well and truly out of injector duty cycle. I'd been a bit lazy in looking because the mixtures weren't too bad (0.84-86's) and it wasn't pulling timing really. I'd crunched the numbers by using vcds injector open times(ms) and the rpm I was at and put it all into this little calculator: Stealth 316 - Injector Duty Cycle Calculation
I was up to 95% IDC which meant I had zero room for error eg bad fuel batch, fuel pump starts to struggle etc and I'm in trouble.
First up I thought it could be the pump. Big thanks to Louis who sorted me out with his uprated pump from his previous tune, but the issue was still there so it wasn't a fuel starvation problem. I got my stock 315cc injectors cleaned/flowed to make sure they were in good condition but problem still there. Seb from eurorevolution then sorted me out with a 4 Bar fuel pressure regulator. Basically for a given open time this will force more fuel through. The ECU then adapts and starts to shorten the duty cycles on the injectors until things come under control again. Well this worked a treat. The specified ambda of 0.83 was met almost exactly. Once I got my silly stuff up with not resistoring the SAI solenoid plug sorted, my O2 sensor was able to go into closed loop and I suddenly had long term fuel corrections in VCDS block 032.
TUNING WITH LEMMIWINKS: Basically this block had an idle (secondary/additive) and a partial throttle (primary/multiplicative) fuel trim %. The FPR will determine the wide open throttle fuelling, but next you need to look at the partial trim = all things between WOT and idle from what I could tell. A negative % shows that the ecu is trying to pull fuel out of it (shorter duty cycle) because it is running rich. This is what I had which makes perfect sense because of going from a 3 bar to a 4 bar FPR. So I basically obeyed what it said and would go into Lemmiwinks and subtract/lower the primary /multiplicative fuel trim by the same percent. I'd read that lowering by 80% of what the trim in 032 says is a safer way to sneak up on the right mixture but I found that like for like did the same anyway without any overshoot. So once I got the partial % sorted with Lemmiwinks CH10:primary/multiplicative, the idle % in VCDS block 032 more or less fell into place. It still needed ch08: secondary/additive trim to be decreased from its 100% starting point right down to 60 something %, because it was rich at idle too.


But in the end both fuel corrections in block 032 stabilised and WOT fuelling was bang on what the tune wanted but with 80-85% IDC (much much safer) and it was driving great and making some good power. It still needed some start up fuel enrich and cold start fuel enrich fuel removed with Lemmiwinks but given the fact that its about to be all redone I never bothered. Here is a log from a third gear pull. I think I'd only added 5 or so degrees of global timing in Lemmiwinks. You can see there is stuff all timing pull but it was making 185g/s through the MAF at about 6400rpm which was pretty solid - about 235HP I think.

So this little chapter proves a few things. If you are stage 2 and port your stock manifold and run a ported K03s wastegate tunnel in the turbo your boost peak will jump up due to the better breathing being able to spin up the turbo further compared to a stocker. This needed a pneumatic fix to get the boost peak under control but isd proof that there is gains to be had in creating a sort of stg2 ++. But, in doing so the stock 315cc injectors are maxed out. Short of going to 380cc S4/TT injectors on the 3 bar and retuning I went for a 4 bar fuel pressure reg and used Lemmiwinks to adjust the fuelling. Yes Lemmiwinks is ghetto but it does have some capability with fuelling, so what I did above shows that it can work until say you get your other bits together for a proper tune.

edit: each time you read off the fuel trim in block 032 and make a concurrent adjustment in Lemmiwinks, you need to go back into VCDS and clear fault codes. When you open fault codes there will be non there, but click "clear fault codes" and what this does is reset the short and long term fuel trims. So if the LTFT said the partial fuelling was 13% too rich (by showing -13%), you would go into Lemmiwinks and subtract 13% from Ch10 primary/multiplicative fuel trims. Then you would go into vcds and clear fault codes. Straight after you would check block 032 again and the fuel trims should have all reset back to 0.0%. Drive the car again for an extended period and then at the conclusion of that go back in and check your trims to see what they are saying to do. eg they may still be slightly negative meaning you need to continue to pull fuel out or they may be saying its a touch lean now with a + %. All the while the timing is backed fully off. Only once I had WOT fuelling, partial fuelling and idle fuelling sorted, and in that order, did I do some power runs to check that all fuelling was ok and then I started adding timing. Another point is that because ME7.5 is a load based ECU, from what I could see if you up the boost then load goes up and so soes fuelling. I found it best to be doing the fuelling adjustment at spec boost. I found that if I got fuelling correct with the boost turned down, that I would need more later once the boost went up. So right or wrong I had boost at spececified levels, sorted the fuelling with timing way down, and then only had to find the timing thresholds later too. Again right;y or wrongly I'm not into the whole push it till 6-7 degrees of timing pull happens. To me that's insane because the ECU is basically seeing knock. What if then you run in 35 degrees on a heat soaked intercooler up a hill or you're on the track with 130 degree oil temps, I think you're just asking for trouble so I look for the beginnings of 0.8-3 degrees of pull here and there and then come 0.75 degrees back from there.

[simon k]

this is very clever stuff - really really clever - I'm continually impressed with the way you work through problems, and then document it for us to learn from

it's time I started tweaking things in the ECU instead of just reading about what you're doing

[sambb]

thanks mate. Lemmiwinks is totally kosher for timing adjustments or idle speed tweeks etc, but these days pretty ghetto for tuning. In the past it was pretty heavily used for that though. It worked for me luckily because of all things it does give you control over fuelling and that was my particular problem. I've always wanted to have a play with it and finally had the need to and it worked well, but now I'll be getting into the proper tune - next week or so.

[sambb]

added a little edit to the end of the Lemmiwinks post

[simon k]

thanks mate. Lemmiwinks is totally kosher for timing adjustments or idle speed tweeks etc, but these days pretty ghetto for tuning. In the past it was pretty heavily used for that though. It worked for me luckily because of all things it does give you control over fuelling and that was my particular problem. I've always wanted to have a play with it and finally had the need to and it worked well, but now I'll be getting into the proper tune - next week or so.

I figure it's the right thing to use for minor adjustments once you have the ECU tune set up - the way you've been doing it. The more little tweaks you put in through there, the less 'correct' the ECU tune will be, so it'd be a matter of adjusting the ECU tune and zeroing out the adjustments in lemmiwinks.... is that the right way to think about it?

so what's the hardware change? same as Louis?