Hi guys.

Bazaa and I were recently discussing the Revo Technik stage 2 remap for the 225 & 240 PS Audi 1.8T engine variants so I suggested I post up my VAG-COM logs during WOT runs in 3rd and 4th gear for general interest/discussion. I included a sub-set of these results in my 'beginner's guide to ECU remapping' document.

The background to these logging runs was my general disbelief of the rolling road dynamometer results obtained before and after the remap. The agent estimates transmission losses during a run down from peak engine speed and adds this on to the wheel output which gave peak outputs of 256 bhp & 350+ lbft. I felt the bhp was maybe 8-10% too low and the torque far too high, so I sought some alternative ways of estimating or calculating this from engine parameters.

BHP is estimated from the tried and tested expression BHP = MAF/0.8 for 1.8T motors, but I have also logged block 120 which has some measurement of torque and then back-calculated BHP from this. I don't know how this figure is measured/calculated and would be grateful for advice on that. Suffice to say that it is much lower than the dyno figures. The data in blue type are all calculated from the logged parameters.

Bazaa commented that there was some general dissatisfaction with Revo remaps on forums relating to rich running, etc., but the view on the forum I was previously a member of was that the outputs were highly optimised and very satisfactory with little evidence of undesirable side effects. However, you can see some rather high IDCs (up to 148%) on the 4th gear run compared to maximum of 98% on the 3rd gear run. I would like to credit Morgan Evans of Vagcheck in Staines, U.K. for his advice on this.

There was also a great deal of discussion about the supposed benefits/advantages of higher octane super or premium unleaded fuels in terms of peak outputs and greater fuel economy, but nobody ever investigated it or obtained any objective data so all arguments were based on hearsay, opinion and the good ol' butt dyno only. Most TT owners, whether remapped or not slavishly stuck to the premium or super unleaded products with Shell V-Power 99 RON being the most popular. I grew rather tired of this and sought to find out whether the standard supermarket 95 RON fuels were significantly worse in terms of fuel economy and require greater individual cylinder timing corrections during WOT runs to cope with more knock events from fuel of higher calorific value.

I have not repeated the WOT runs with supermarket 95 RON fuel yet, but am currently nearing the end of my second tankful of the cheaper fuel during which I have deployed 'hypermiling' techniques including gentle acceleration and cruising at 60 mph on the highway. All my mileage nowadays consists of 36 mile round trips, of which, 95%+ is cruising in relatively light traffic two lane highway (dual carriageway in the UK) giving a consistent baseline for comparison. So far, I have been able to EASILY add 50 miles to my range and 3-4 mpg by driving carefully.

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Hi Doug
Thanks for posting your logs
Those IDC's are extremely high are they standard injectors and fuel pump your running,
As an injector can only really be 100% max/open all the time i guess that's got to be a commanded value opposed to real injector value,but i notice they are only exceeding this at very high revs so probably exceeding the IPW .Might be time for some larger injectors with those figures .lol

Doug,
As a 1.8t owner your approach is exactly what I wanted to hear. Forums are usually breeding grounds for nonsense so an evidence based approach is so refreshing.

I agree 148.1%
where in the uk can you really sustain full load and drive at high rpm for any time and the expence upgrading would as you say will be uneconomical for minimal gain .I know i couldn't jusify it.
Bazaa

Hi Julex. A good contribution, thanks.

Although I failed to mention it, I think I realised intuitively that for economical cruising and hardly any/no full load acceleration, knock events will be limited so there is no advantage yo using the premium fuel as you say.

I had also rationalized >100% IDC as pre-injection based on the odd fuelling regimes I read about in the lean burn type strategies deployed in the FSi engines. I'd rather it was <100% but EGT seems to be under control so I don't worry.

Doug

Doug

Reminder: a FULL cycle is two rotations!

So yea, rick, I agree. 100% is static, as in, fully open for two full crank rotations.

Incidentally, the 'hypermiling' experiments extend to my wife's car, a MY2005 E12 model Toyota Corolla 2.0 D4-D 5-door hatchback with a 55 litre (12.1 imperial gallon) fuel tank. Specs here:

http://www.toyota.co.uk/vs2/oldpdf/05/CO6_63_spec.pdf

My previous best range was 508 miles from a brimmed tank to the low fuel warning light illuminating but my wife typically gets maybe 400-420 miles before she is near the bottom of the fuel gauge and has to refill (not to LFW though).

We recently took a week long break with the car carrying two adults and a full load of stuff which involved 160 miles of motorway driving. I drove economically at all times and stuck to 60 mph on the motorway. The low fuel warning light came on at 549 miles. I think 575 is possible but my wife had driven the first 74 miles at an indicated average 47 mpg so I was on the back foot from the start.

It's not much use talking about indicated fuel consumption because the offset appears to be large (maybe 25%) and highly variable, but indicated fuel consumption when I refuelled was 63.2 mpg. When I refuelled and drove the remaining 17 miles home, the displayed mpg was showing 76 mpg and was as high as 84 mpg at one point. So irrespective of the actual numbers, there are big gains to be had by driving sensibly.

Doug

But that's only typical of stupid (yes I mean it) US drivers who have exactly ZERO driving education and even less courtesy ending in asshole(s)/(lettes) (yes I mean it again) driving in left lane at or below speed limit.

When I see priuses I just shiver and basically absolutely rudely cut in front of them once I manage to pass one after that ass blocking fast lane for the last 5 minutes.

Every european driver is told and enforced by law to sit in right lane unless he/she is passing which implies going far above speed limit.

I central europe/east europe you're guaranteed to have somebody riding your ass/flashing lights/etc if you anything below 2x speed limit on the left lane. Cops will give you a ticket for violating law b/c you drove left lane constantly without intent to pass.

In US I noticed that having 3k HIDs in fog lights and having them on 24/7 (by re-wiring the harness) gets peoples' attention to GTFO of your way. . I get lots of "V"s from audi/VW folks too.

Sorry for rude post but the post above just struck some nerves there.