Tuning a 90 hp engine


i have a 97 NA which has both low milage (23k) and is totally stock. I would like to improve the power without going down the turbo or supercharged road. At present the engine output is 90 horse and I am toying with skimming the head by 50k. What other options can I do whilst leaving the car looking as stock as possible. I have a lsd and 6 speed box which I can put on the car 

Any help and advice will be gratefuly received

All the best 


Frankly, if FI is not an option, I’d drop in a 130 bhp 1840cc if you have an LSD & 6 speed at hand.

Your engine ironically used to be the preferred choice for FI back in the day due to it’s low compression ratio.

Clearly, we are talking ECU change and a few other bits.

I’d chat to AK Automotive nr Newcastle…they are a trusted supplier (one of a few) and transplants are a matter of course to them.

And if you do…see if they have a VVT 140 -odd bhp from a Sport etc Mk2.5.

Engines are still dirt cheap…say £150/£250 for a known oil tight runner.

Maybe a bit more for a good VVT mill.

I would not chuck money at an old 5 mill now…despite it’s low miles.


Double post.

The other inexpensive option is to change the cams back to the cams on the more powerful 1.6’s but then you need a new cambelt etc.

Even then it starts to mount up if you are not doing it yourself.

Still a bit of a power loss compared to the original 1.6 as you have the low compression pistons.

Therefore a nice 1.8 lump may be the best bet.

Looks like he’s struggling to get up the drive with90hp Eddie

Get a head from a 89-93 1.6. Get 50 thou skimmed off and fit it with the cams. Should give between 105-110 bhp

Thanks for all the advice guys. Sorry i have been slow coming back to you all but have been without Bband due to some idiot ( me ) digging up the line to the house with his tractor! I am in a rock and a hard place here as the car is in original condition, no rust, 23 k on clock etc   The value in the car will be seriously affected by making alterations such as changing the engine or the induction route. It may well be worth skimming a head from another engine (I have one to caniblise)and change the cams as well.  The benefit will be that the car will ostensibly look original. I have put an 1800 into another car and in fairness it is a worthwhile upgrade. I also took the time to remove the power steering and air con at the same time. It is a pain in the arse trying balance upgrades while attempting to maintain originality ???


Keep this one original, and look around for an already modded play thing???

i am being greedy as I have a turbo’d 250 bhp  Eunos, an 1800 and another 1600! I am just trying to improve the performance of this one to make it a more enjoyable drive. 


I’m not sure how much value there is in keeping the car original but if there is maybe keeping it completely original will bring you joy if you have the other toys to play with? 

To be honest nor do I. The value on low milage rust free NA’s are holding their own I am just trying to improve the overall performanc. The reason Mazda put the uk poverty spec together was to downgrade the car to improve the sales of 1800’s and the imminent arrival of the Mk2’s.

its a shame as they had a winning formula 


Just rev the nuts off it and enjoy the feeling that you are redlining without damaging the engine in any way. You will never feel the benefit of a 240bhp MX5 unless you take it on track, but you can fully enjoy the 90bhp on our roads.

There lies a certain wisdom.

The late great James Hunt’s preferred fun car/thrasher was of all things his Austin A series estate…with no brakes or power.

I feel I need clarify why I am looking to improve the performance of the car. I am lucky to live in rural Wales with fantastic rural roads with superb corners. Not only this, there are no speed cameras, humps or other restrictions apart from the odd tourist on a summers day, tootling around in their often underused soft tops. I don’t want to overboot the cars performance, nor"screw" the arse of it. James Hunt in his latter years not only loved to drive his A40 van but transported his much loved budgies within it, lets face it had no reason to rush.
Having had many such vans over the years I can see the attraction of them, however I enjoy driving my cars and improving the experience and not living in a town or city has its advantages