Hartech ECO-POWER Engines

[bazhart]

On this subject it would really help us with our R & D if any readers with any of the models mentioned above in std capacity and trim form that keep mpg records for road use would kindly post them on here so we can create a statistical comparison.

Many thanks,

Baz

 

[Hugh_]

I'm sad and have a spreadsheet of the last 14months/7k miles fuel, let meknow how you want it!
3.4 c2 standard except Cargraphic silencers.

24.13mpg average, low of 19.08 over 101miles, and high of 27.39 over 307miles.

 

[911munKy]

In the first year of my 996 C2 I kept fuel records (standard except for Top Gear sports exhaust & Helmholz bypass) and got 26mpg average if I used the car for work (100m round trip & 85% motorway [80-85mph] & 15% booting it around country lanes). If I used it to drive into the nearest town/school run and got stuck in traffic it dropped to about 21mpg or less.

Approx 300m per tank with motorway driving and free flowing roads, best was about 350m zooming down to Le Mans @ 100+mph.
I get better mileage out of 98/99 RON which offsets the higher cost.

 

[Alex]

From a trip I did down St Trop (car fully loaded with 2 adults and dog child + plenty of wife's luggage):

Just thought I'd do a quick post about my drive down here. Set off on Tuesday afternoon around 3.40pm down to folkstone. Brimmed it with 95 ron to see how it ran and how I'd go on with the dodgy tickover I've had.

Motorways in the UK were pretty decent for once and only saw heavy traffic around Oxford and M25 near Heathrow. Mostly on 70mph on the sat nav and averaged 34mpg. Arrived mega early at the chunnel (9.00pm for 10.50pm crossing) so they slipped us on the next train at 9.30pm. Train was nearly empty, we were the last car and all alone in the 3rd carriage back.
Turned the gas up in France as I wanted to cover distance whilst it was quiet so 85 on the speedo (80mph on the sat nav). Borrowed my Dad's zapper thingy for the tolls so drove through around 20mph - deffo want one of these, no toll ball ache whatsoever.
Didn't fill up till just north of CDG airport in Paris (465ish miles) and ran out of fuel on the slip road into the services so just managed to free wheel up to pump.
Next stop about 70 miles south of Paris to let the other half take the wheel as my eyes were throbbing. She got the worst part as it was proper pea soup with fog. Had a quick hour power nap and took over driving duties just south of Dijon.
Didn't fancy hitting Lyon at 7.30am so turned off down to Grenoble to hit the scenic route from there to Sisteron - very nice drive and loads of good roads and overtaking stuff.
Stopped for a picnic brekkie just North of Sisteron, then the last blast down to St Trollop.
Final mpg came in at 32.3mpg and the car never missed a beat.

Clocking off now, my Rose's getting warm

Wish you were here & a bientot! :bye:

 

[SidewaysSi]

I have a Hartech 3.9 in my 996 and haven't done a proper brim to brim test but the computer is showing 23mpg average. Managed to get 31 mpg on a slowish motorway run which is the best I have seen.

 

[maldren]

I've logged mine since I got the car, 28MPG over 20.5k miles. That includes a mix of spirited driving with motorway and in town use (I live in Greater London).

I always 'brim' the tank and the mileage is obviously dependent on the accuracy of the speedo, let's say 3% over so you could argue that it's really 27mpg.

I usually use Tesco Momentum but sometimes I have to use 95 octane. Not sure I've seen a consistent, fuel dependent difference in tank mileage which varies between 20 and 30 mpg.

 

[bazhart]

Thanks guys and gals, more please to set an average.

It does seem that the 3.6 and 3.8 (or 3.9's or 4.1's) achieve a better improvement than the 3.4's probably because the variable valve lift addition improved lower down torque (where we all drive most of the time).

Baz

 

[Poker2009]

There must be something wrong with my 997, as I am always at around 13mpg. If I hit the motorway, it is about 15mpg. I think I need to go for this 4.1L upgrade, which will also hopefully will fix any hidden issues I have.

I am convinced my problems started when I fitted a LTT, perhaps it needs a re-map?

 

[Alex]

That's horrendous......do you leave a trail of fire behind you like back to the future?

 

[Poker2009]

I don't, but this thread has prompted me to check out chipwizards website!

 

[sp1ke]

mine is a 3.6 which had a Harlech rebuild back in 2013, prior to my ownership. If I drive sedately, the OBC can show 30mpg on a long motorway run, but it's averaged 23mpg over around 10k miles of mixed London/motorway/spirited backroads.

 

[Ghianightmare]

In the absence of actual data, my sense is that my MPG is about 10% better since the 3.9 went in based on the on board computer. it could be 15% but I couldn't support it.

It still hates the school run.. stop start... about 10mpg over 4 miles...

The other day on a motorway section I reset the trip computer and with a steady foot I achieved 36mpg at a steady 65-70 mph (possibly a tail wind). Noting again that is based on the on-board computer. I think that is about 2600 RPM. I have a sense that the MPG is better at about 2,900 RPM. I didn't get a change to check.

I dont think mine would ever achieve 40mpg average.

Aside from the improved MPG - Hartech is supporting the circular economy part of the sustainability initiative. Re-use, recycle, etc.

 

[Wurzel]

There must be something wrong with my 997, as I am always at around 13mpg. If I hit the motorway, it is about 15mpg. I think I need to go for this 4.1L upgrade, which will also hopefully will fix any hidden issues I have.

I am convinced my problems started when I fitted a LTT, perhaps it needs a re-map?

Does the LTT take longer to warm up the engine ? Does it get up to operating temp ? Does dropping the engine a few degrees prevent Bore scoring ?

 

[Alex]

Does the LTT take longer to warm up the engine ? Does it get up to operating temp ? Does dropping the engine a few degrees prevent Bore scoring ?

All you answers here: http://911uk.com/viewtopic.php?t=89494

 

[Wurzel]

Thanks, :thumb:

Off to educate myself on this, It's too late for me now at 180k miles but I'm curious as to whether my Indies comments will be contained within the thread.