I have a standard 1991 manual TT import. Since fitting 18" rims MPG has dropped from around 19mpg to 15mpg under normal driving conditions. Fitted 235/40/18 front, 265/35/18 at the rear. I understand they are bigger than standard and will throw the speedo out slightly. but not to loose 4mpg? did calc, should only be 3%, anyone else had similar probs? Any Ideas? Also want a superchip. Does this affect mpg under normal driving conditions?

hmmmmmm,Superchips,do search on here,supposedly crap for the zed

I also have an imported '91 manual tt. I get around 25 m.p.g.

It came with standard 225-50-16s all round. However I changed the tyres to 225-55-16s. It helps the ride, raises the gear ratios, reduces the revs for the same speed, and I have not noticed any change in acceleration or cornering. Mind you I am a lazy driver in that I hardly ever go over 4000 revs and the torque is so good that the car will drop below 1500 revs in top and still pull away stongly. Perhaps not the way it should be driven, but it will go when I want it to move.

 

Stuart S

Hi Andy,

I have a 1990 ZXTT import with 18inch wheels and never get more than 15mpg out of it. I have got a heavy right foot though:D

 

 

Glenn

Hiya mate.

 

£10 of OPTIMAX gets me 25-30 miles with my lead foot.

15mpg probably isn't too bad if you have heavy feet, driving lots of short journeys in the winter etc. However, if that is throughout the year then you should be looking closely at your MOT emissions test results and considering whether you have a subtle problem like a sticky O2 sensor.

 

I monitor my fuel consumption very closely (to the point of being anal about it!) and when it dropped from 20-21mpg to 17mpg I started looking for problems and found that my LH O2 sensor was heading south. Fixing that (and replacing the PCV's) immediately put the consumption back to about 20.5mpg.

i put £30 of optimax in at a time & get 140-160 miles out of it. including driving hard every now & then ;)

At best thats still 50 miles different Paul, oh, am running higher boost, cats out and induction. You modded at all? I ran o2 test and they were fine.

around 400 bhp ;) . induction, exhaust, lightweight flywheel, chip, 1 bar boost

your not having high idle speed problems by any chance? my mpg started to drop when my idle speed increased, traced it to dodgy connectors on the engine temp sensor. (even though they looked ok in the connector) just a thought.

No, idle's spot on. Fancy sharing those extra 50 miles you got on me? come on, chuck 20 my way!!

 

I do alot of short journeys so this is probably it! too many short journeys-will get 2nd car, 8v golf mk2 I think. Then put Z on classic car ins, had quote already for £348 from Lifesure.

i was thinking of keeping my golf when i got my zed, but once you work out the cost of running another car, insurance, petrol, servicing etc it actually ended up costing me more - & id rather drive my zed! ;)

Don't get me wrong, I'd much rather drive the Z around. But all thru the week it does a stupid little journey to and from where I work (but too far to walk) and I need my car sometimes at work. Don't think its doing it any good really. I can insure the golf AND the Z for just the price of the Z if not on classic insurance. I'd be at work happy with the thought my Z is all tucked up and dry in the garage! come the weekend or evenings it would come out to play and all shiny and lovely! :D

 

.....and a roof-rack on a Z would look really silly for mine and my mates surf-boards!!!!