Tuning manifold port and polish?

[mozart]

i want to port and polish the exhaust and intake manifold as cheap alternative to headers and uno45 intake manifold as it is free with the minidrill .has anybody trye something like this? i have read that the trofeo 900 run with the stock manifolds probably modified

 

[rallycinq]

the standard rules apply.

Polishing is not necessarily the best for inlet, it needs some surface roughness to 'tumble' the mixture.

It is a good idea to port match the inlet, use the gasket as a line. (This doesn't work on 899)

A step for the exhaust is also considered good to encourage scavenging.

Cheers

D

 

[mozart]

thanks for the reply ...so just port match the intake manifold and open the runers or not? and the exhaust manifold i should port match again but do not eat the step or eat it? thanks again

 

[rallycinq]

thanks for the reply ...so just port match the intake manifold and open the runers or not? and the exhaust manifold i should port match again but do not eat the step or eat it? thanks again

Port match the inlet, open the runners (do not go through the water jacket). Not too smooth.

Port match the exhaust but leave a step at the bottom

Cheers

D

 

[mozart]

thanks rallycinque you save my manifold because i thought that the main job was to eat that step ..if i didnt eat it how can i enlarge the ports? the supersprint manifold also have this step?

 

[mozart]

ralycinque it is better to find a used supersprint manifold or a custom than modifie the stock? i hear the hp gains for engine with not so aggresive tuning is litlle for header so what is worth to do?

 

[rallycinq]

Without stripping the engine and doing 'everything', all that you are doing is 'tinkering'

There is no way of knowing the health of the engine that somebody else is working on.

It also depends on what you want/need the car for.

Mine is very highly tuned, but is a pain in the ass to drive slowly. There is no torque to speak of, all the power is the wrong side of 6000 rpm.

Cheers

D

 

[mozart]

the engine is healthy and well servised and peaky for just chiped and panel .
it start pull from 3500 to 5500 ... i feel that it can not breath at over 5000 rpm
.it is my second car i have also a cupra leon r but as my wife is pregnant i will put the back seats and make the leon family car....so the track day car will be the litle sei...every litlle advice help....75 ps , torque and low fuel consumption will be a dream ....

 

[fingers99]

75bhp should be easy enough from a 1.2, but a bit of a stretch for a tinkered 1108.

I'd suggest a ported Uno 45 inlet mani, forty mm TB, superspring exhaust and a chip and a P75 cam.

 

[mozart]

uno45 mani gives any hp? i cant find it cheap is it worth ? it is better but smaller ports

 

[rallycinq]

Its where you want the horsepower thats important.

You get horsepower from revs assuming the engine will flow what you need at those higher revs, and that the engine will take it.

Mine is balanced to 8K, I have the rev limiter set to 7.4K and the bhp is still climbing at 7.4K.

But, and in answer to your other post, if I use all those revs I average 19mpg on a 100 mile event.

Cheers

D

 

[fingers99]

uno45 mani gives any hp? i cant find it cheap is it worth ? it is better but smaller ports

It's a better shape. One German tuning company -- can't remember their name, but a search may throw it up -- was doing them as a go faster part. But it will need some porting to suit the 1108.

Worthwhile rummaging for, or maybe a wanted in the Uno section.

 

[cc1]

It's a better shape. One German tuning company -- can't remember their name, but a search may throw it up -- was doing them as a go faster part. But it will need some porting to suit the 1108.

Worthwhile rummaging for, or maybe a wanted in the Uno section.

This one?
http://www.bielstein.com/FIAT/Cinquecento/cin04motor/cin04motor.html#Ansaugkruemmer

 

[blu73]

looks like it.. You haver to make sure you get one from an uno with injection and not carbs though if you go trawlling for one secondhand..

 

[mozart]

find the time to start the project again i have already find t/b new cam ,new chip
for the cam ,and new intake . rallycinq can you draw or put a pic what you mean step in the exhaust manifold ? i want to open the exhaust manifold as i read that the punto or supersprint gives 1 or 2 hp alone or with not hard tuning ..the stock is more torqy for mild tuning ....also port match the intake ports and port polish the exhaust ports .if i find it esy i will also trye to smooth the edges in head but i will not do anything in valves and valve seats as i am afraid ....please any pic for the header step ..thank you i will post fotos as soon i start

 

[fingers99]

Just about all you need to know is in any decent tuning book. I like the A Graham Bell "Tuning 4 Stroke Engines" one (Haynes).

But flowing really needs a lot of experience and a flow bench. As Rallycing says, restrict yourself yourself to port matching.

 

[mozart]

its ok to just port and polish but what about the step in exhaust manifold ?

 

[fingers99]

Don't polish. It's a complete waste of time and effort and may loose you power.

Simple enough. Either don't fully port match the exhaust ports in the head at the bottom (assuming they're a bad fit) or introduce a lip (brazing, or bolting in a peice of steel between 2 exhaust gaskets). The books will tell you more. All the best engine builders read a lot.

If you look at the Supersprint, it's a damn wierd fit on the exhaust side. My guess (seeing that their 16v ones are a perfect fit) is that it's deliberate.

 

[mozart]

so better let the head alone and buy a punto 75 4-2-1 manifold ?

 

[fingers99]

Better to put the two together. The P75 is a good mani but should be too long for a cento, so it'll need fettling any way. Portmatching good, polishing bad.