Tuning for better mpg

Hi all,

I haven't posted on here for a very long time. I decided to take a change in direction last year career wise which has meant less £££ to spend on the coupe for a while at least.
I toyed with the idea of selling and buying something more fuel efficient which needs less maintenance, doesn't rattle and can drive around London without making me cringe every time I see a large speed bump, but its hard to let go.

I decided to take the coupe of the road for a year and put the money I save towards upgrading the suspension, getting the body work up to scratch (no pun intended) and perhaps get some head work done and a remap to help with fuel economy.
Maybe I'm getting old but this change in jobs has made me realise how much money I used to waste, before I would have looked at head work and a remap purely for more torque!

At the moment I have a stage 3 hybrid turbo on there with an evo fmic, 2.75" downpipe, walbro fuel pump with wiring mod, gtec2, apexi avc-r and a wideband afr gauge to keep an eye on fuelling.

I just want to know if you guys think head work and a remap would make much difference to mpg? Would be great to hear from people who have had head work and a remap with a pretty basic 20vt set up like mine.

Thanks for your help.

John

Not enough to warrant the four figure sum, unless you're doing 50k a year!

Headwork and a remap pushed down my fuel consumption from 250 miles per tank to 300 - every tank lasted 50 miles, or about two gallon longer, saving me about £12 per tank.

At the rate of about six tanks per month, I recovered the cost of the head within a year and the remap costs a couple of months later.

I had the head for five years, so it paid for itself about four times over

IMO the biggest reason for mpg is the driver. If you can change your driving style it will cost nothing and save your more than anything else. Do some googling there are even apps for your phone.

I can also say hands down, head work makes a very noticable difference to economy.

However rather than spending a 4 figure sum, you could spend a 3 figure sum, buy and have yourself a 6 speed box fitted. (If you don't have one already). Just another fuel saving option.

Apologies for a potential thread hijack; but would head work improve economy for a standard motor/turbo?

Yes agree with most of above!
I think a better tuned car such as a Flea map would be more economical if driven "economically" than an untuned one.... I think
Definitely would recommend Flea I'm sure he could accommodate your requirements!! highly recommended by me!!!

To quantify the mpg improvements, I have seen as much as 43mpg over a distance of 375 miles when trying REALLY hard and easy mid to high 30s when cruising at the speed limits

Im no expert, but I beleive it would.

From my experience, the extra partial throttle torque you gain from a re-worked head, allows you to make the same, if not more power using considerably less throttle, saving you fuel.

I get asked this a LOT, especially from some of the gas guzzler engines out there. You have to be totally realistic, the returns are based on an average according to the number of miles and owner driving style. If you do very few miles, or drive short distances, or experience slow/heavy traffic then there is really nothing that can be done. Think about manufacturer claimed figures, and then try matching them! Making an engine more efficient without significant changes is very hard, especially where emission compliance is required. The 20vt engine is very efficient, for a 90s engine it is frankly fantastic and will happily compete with many modern engines of the same capacity in this regard.

The key to efficiency is torque and gearing, something that diesels do very well. So emissions aside, we need to maintain or increase torque for the same injected quantity and gearing available. For a petrol engine this is very hard to do, but it is possible to lean the engine away from stoich, especially when cruising, in order to allow maximum torque and fuel efficiency. The gains are based on driving under these conditions, and yes over time they will certainly mount up.

Thanks a lot guys. Nigel I know you have said before that the work you had done improved mpg and is something that stuck in my head.

If it is going to be mapped with headwork or otherwise I did have you in mind Flea and appreciate the information. Part of the reason I haven't been able to sell the coupe is because I know the engine is pretty efficient considering it's age, performance and cost. When I look at cars for sale online whilst comparing figures and dreaming I often come to the conclusion that my money would be better spent on improving the pretty looking beast I already have sitting on my drive. I must admit I do sometimes find myself looking at the mpg of some of the hybrid cars!
I guess i'm not sure where the coupe fits in at the moment, I couldn't imagine taking it of the road only a year or two ago.

Thanks everybody for the info and advice.


Cheers
John

Got 417 miles before filling up yesterday. Tank not even empty... but not far off.

Did my usual mpg calcs, and only averaged 29mpg.

Using Tesco Momemtum cost me £87 to fill up.

OUCH !