how many bhp can i get from a 1.8 zetec engine without turbo?
Is it worth inastalling a turbo system or i will increase my overall weight very much?

for a N/A engine, considering cost and parts availability, 100bhp per litre is a practical limit - so around the 180bhp mark - this could be done by raising CR (skimming the head), increasing airflow (cams, headwork, extractor manifold, exhaust and filter, throttleboddies) , raising the fuelling (again through throttle bodies, better fuel pump) and by reducing overheads (lightening/balancing - which can also help the engine rev higher). Other options are forced induction (turbocharging, supercharging or compound charging), nitrous oxide, cc increase or alternatively if u just want to go faster, you could look at changing gear or diff ratios, lightening the car, improving brakes, suspension or grip, fitting a quick rack, fitting a quick shift etc.

In practical terms, a re-chip, cams, headwork and extractor manifold may well give you an extra 25-35bhp depending on how agressive each mod is - but always remember that power and reliability are inversely proportional - especially once you go past the few-bhp 'safety net' that manufacturers build in to allow for things like poor-quality fuels, emissions, economy etc.

Forced induction is going to cost more, but will probably give you more power (although in the case of turbos will likely give you less usable power lower down in the revs - inless it's a very well designed system). What you will probably have to do is fit lower compression pistons, custom inlet and exhaust manifolds, stand alone engine management, better fuel pump, possibly bigger injectors - then a shedload of rolling road time to develop the fuel map - expecially if the engine management manufacturers don't already have a 1.8 zetec turbo fuel map (some tuning companies may already have one - ask around)- so allow from about £2500 upto £5k) Supercharging will set you back a similar amount.

Nitrous is probably the cheapest way of getting big php gains whilst still retaining fuel economy and driveability whilst off the button. But be warned, you are likely to incur the wrath of many prejudiced people if you dare to think about nitrous....
In all seriousness, if you spend a decent amount of money and buy decent kit, there's no reason why nitrous isn't going to be reliable and safe. Off the top of my head, the Wizards Of NOS have a good reputation, have been around for a while, and use good quality kit.

You're probably best off talking to a ford speciailist tuner - they may already have turbo conversion packages for your engine, or NA tuning packages already put together to get you the best performance increase per £

Try some of the boy racer forums like www.cruisesouth.co.uk/newforum30.3/index.php or the forum on www.cruiseboard.co.uk - or even the RSOC forums - a lot of the boy racer / cruiser forums get dissed as LED washerjet brigade, but some of the ppl on there are quite knowledgeable and some may even have done what you're trying to do. It's worth a few minutes sticking a post up.

130 PS cams, Weber 40DCOEs + tubular exhaust manifold = 155bhp
Use throttle bodies instead of Webers better drivability and 160bhp
Skim head and clean up around valves with throttle bodies = 175bhp
Over 200 bhp available with more head work.

Forget the turbo and NOS

Remember you are building a 600Kg car, bhp / tonne is more important than overall bhp. Most of the sevens I have seen run at between 100 and 180 bhp, beyond this the car becomes a little unusable on the road due to the excess power. Great for drag strip style sprints though

whats a west-field lover doing on this forum?????,there just spend the cash kits and get your spanners out to all look the same kind of looking cars...heh he eh eheh

I agree that forced induction would be a waste of time, but a progressive nitrous kit would be a useful addition imo

for all those against nitrous - check out topgear this coming sunday - the bloke who owns Wizards Of NOS (Trev) is running a £50 jag fitted with nitrous against supercars - I don't get why all small minded people will discount a potentially viable tuning option just because of a few f***ing rumours and some dodgy US film. Do your own research. Make up your own mind.

what fast westie isn't telling you about carbs is that they can only be tuned optimaly for a very narrow power band, independant throttle bodies need a custom fuel map setting up, but nitrous just needs pluggin in (and setting up properly - not rushing) but doesn't need a rolling road, no specialist equipment (although water injection can be a sensible addition) and gives you power straight away whilst retaining economy when off the button. Progressive controllers can be used to adjust the level of nitrous injection at different rpms so as to avoid shocking the tyres and breaking traction. I'm certainly going to be fitting it to my locost when it's built

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whats a west-field lover doing on this forum?????,there just spend the cash kits and get your spanners out to all look the same kind of looking cars...heh he eh eheh

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whats a west-field lover doing on this forum?????,there just spend the cash kits and get your spanners out to all look the same kind of looking cars...heh he eh eheh

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I've got a 2ltr Zetec with throttle bodies, suspect 160-170BHP. Just driven to MOT centre and back and from that suspect that any more power would be of little use on normal roads as it spins wheels easy in 1st and 2nd gears (LSD fitted!) Start with a basic engine, good for 155-160 and see what the car is like on the road. The ECU and throttle bodies route is better option if upgrading head/cams at a later date.

westie - yes I have used nitrous (NOS is a brand name - and a pretty inferior one at that) and from the typicaly prejudiced and ignorant reply you have posted, obviously you never have. Yes a bottle will run out in 1-2 mins of continuous usage, but who the hell would run a bottle continuously????
A progressive controller will further help increase the amount of time your bottle gives you, as it feeds nitrous in gradually as and when you need it, so stops you wasting it.

Budget controllers are a couple of hundred pounds.

Burning pistons? Did you perchance read a badly written article on nitrous from 20 years ago? The only people now who kill pistons/rings are people who use 500bhp jets on a standard 2.0-ish engine. If you never use more than 50-60% of your engine's factory output and don't jump on the button from the moment you turn the key.
Unless of course the engine has an inherent weakness anyway - are you saying the Zetec is a weak engine?
Bottom end uprated? Well, pistons has already been covered so I can only assume you mean the crank. yes it has been known for cranks to snap when on the button, however this has typicaly been at very low rpms in top gear with a lot of nitrous going in (I assume you know about the relationship between bhp and torque?) - again, a budget progressive controller can be set to avoid this occuring.

We obviously have different ideas for 'practical' - if you like, the 'practical' limit for a fiat twincam turbo engine is around 750bhp with stress relieved block, custom oilsprays and many other hardcore modifications - it just won't run for very long.

Any other bolx you care to put down about nitrous?

[Edited on 14/5/03 by RobS]

I often read crap advice given on this forum by people who haven't got a clue. Everyones a "specialist" in the pub on a Friday night or when they have just put their Haynes manual down.

I think it is particularly unfair to give such advice to new builders who may be going to part with their "hard earned" based on either non existent expertise or misguided advice. There is some such advice coming through on this thread, and has been a great deal in the last couple of days in the engine section on this forum.

However, I have always found members of this Forum to be polite, even when correcting others. RobS, I would value your no doubt sound expertise if you could do the same. Billy - do you have anything constructive (or comprehendable) to say?

For what it's worth, and I have 30+ years of professional engine & motorsport experience, I think you are both right - there are pro's & con's for nitrous, both now well explained in the thread.

I suspect the original questioner - Syber - hasn't driven a 170 bhp Se7en. If he had, he may find he was happy with the power. If he has money for cams, throttle bodies, cams, nitrous etc, then he'd be as well to spend some of it on a 2.0 engine to start with.

Go on then, have a go at me now!

david - perhaps I was a little irate, and I'm sure fast westie also has valuable knowledge, it's just a shame when people repeat stuff they know little about. I don't always pretend to know everything, and if I get corrected then I certainly don't keep on saying the wrong things - but david - that was a post worthy of taking note of, so i will do so and refrain from making any more agressive posts (well until the next person start talking rubbish about nitrous anyway.....lol)