[CEDS 2]

Originally Posted by aerobod

The R isn’t tuned at the moment, stock clutch is too weak, it really is the shopping car - I call it the proper SUV, as it does have sport as well as utility.

What I’ve found from tuning my Caterham is that it is very difficult to accurately monitor tune and safety limits without a wideband lambda system installed, the tuners will be using one when building the maps, but the problem is that you may be running different parameters from a fuel and environment perspective than they have tested with. I currently use the Innovate 2 system with a Busch wideband sensor.

Alright, you lost me on the second paragraph...LOL. Also, you should join the FB group "Club Wolfsburg" - enthusiast group in GTA for VW made up mostly of Mk7/7.5 Golf R's/GTI's. Think a couple members there have stage 3 R's.

[Pray for Mojo]

Originally Posted by aerobod

What wide band lambda values with a given timing, IAT and boost pressure at a given engine load have your tunes been using? E10 will produce a 0.025 lower lambda at MBT than straight gasoline without appropriate injector pulse width adjustment, leading to increased risk of knock, Petro 94 is generally tested at over 100 RON (101.5 is what they quote), so is quite knock resistant, if the right fuel flow is used.

It's really low MON, 87 MON nets 94 AKI if it's 101.5 RON. AKI is a pretty awful octane rating system, you can juice the RON which will run great on a simple single cylinder test engine but like crap in a modern 6 cylinder. The AFR difference on 10% ethanol isn't enough to make a huge difference. Even if you run V Power which is pure gas in Canada on the 91 tune it still pulls timing and knocks.

There are very distinct geographic areas where this is an issue. Arizona, California, Nevada, Pacific NW, and Canada. It must be the gasoline formulation.

[aerobod]

Originally Posted by Pray for Mojo

It's really low MON, 87 MON nets 94 AKI if it's 101.5 RON. AKI is a pretty awful octane rating system, you can juice the RON which will run great on a simple single cylinder test engine but like crap in a modern 6 cylinder. The AFR difference on 10% ethanol isn't enough to make a huge difference. Even if you run V Power which is pure gas in Canada on the 91 tune it still pulls timing and knocks.

There are very distinct geographic areas where this is an issue. Arizona, California, Nevada, Pacific NW, and Canada. It must be the gasoline formulation.

The issue is the the highest octane ratings only being available from ethanol enriched fuels, which is certainly the case in these areas.

Going from 0.86 lambda (typical MBT lambda on an efficient NA engine) to 0.89 in a highly tuned NA engine at max power can mean the difference between full power and melted pistons when you are pushing over 30 degrees of advance, potentially up to 40 degrees at 7500RPM. With a medium boost turbo engine 0.75 to 0.78 lambda can make a major difference at max power. This is the sort of difference E10 can make if not properly accounted for in fuel flow.

[Pray for Mojo]

Oddly enough on these cars quite a few people have cleaned up their timing by running E15-20 on the 91/93 maps. The knock resistance of the ethanol seems to help sort out the issue. I was skeptical that this was wise given the differing AFR, but the tunes run so rich (12:1) at high RPM that it doesn't lean out.

I ended up running boostane with Husky 94 to get clean timing and no knock on the 91 OTS map. On the GTR forums guys compare our 94 to Cali 91, for whatever that's worth.

[kivyee]

Seems to me that the reasonable thing to do is to ask for a tune for "Canadian" fuel formulation from the tuners - i.e. something with richer AFRs? Part of the problem here is that your typical modder expects a plug and play system, and don't understand that the manufacturer specs the 99.99% safe scenario, while most tunes are probably more around the 95% safe scenario. There's no free lunch - the extra power comes at the cost of decreased safety margin.