Tuning More compression more power? 1.1spi

[Towsejames]

I don't really know what to expect from this but I'd be interested in seeing what people would have to say. Don't know if it's ridiculous or not?

However, I was talking to one of my dads friends (who's a mechanic) and we was brain storming ideas about getting more power out of my cinq. It currently is a standard 1.1spi with exception of an induction kit, sportex exhaust, and an 866 cam fitted.

I want to see if I can make it faster without having to do anything too drastic like turboing it. In my opinion it's too expensive and hard to find the parts.

I was wondering if taking the head off, and getting around 1mm skimmed off it, smoothing out the inlet and exhaust ports would work and make a definite increase to power? More compression more power?

Also maybe adding a 40mm throttle body? (Don't know if this can be done to the spi?) and would the ecu be a limiting factor?

May sound an idiot but worth a try?

 

[glenn2602]

Nah ... wouldn't have thought so.
If you were going to overbore your engine and skim the head, that may have produced a slight increase. If rallycinq reads your post he'll be able to tell you.

If you raise the compression ratio too much you may get pre-ignition. Way back, Rover V8s were 10.5:1 compression ratio but they were designed to run on 5 star fuel which had a high octane whatsit.. RON .. The engines were later reduced to 9:1 compression and then 7.5:1

There's no substitute for the sheer number of cylinders ...

 

[sparky5]

Also maybe adding a 40mm throttle body? (Don't know if this can be done to the spi?)

The SPI TB can be modded to 40mm, more info. in my gallery.

 

[purf]

Or you could get a factory punto mk1 60 throttle body which is 32mm for a tiny increase ☺.

Removing weight from the car is a good idea if you can live without luxuries and deal with a bit more noise.

Sports springs are a brilliant mod too. Improves handling soo much and can be as little as £70 if your shocks are in good shape.

 

[rallycinq]

If rallycinq reads your post he'll be able to tell you.

I'm here!!!

Yes, and no

It will help a small amount, but, as suggested too much is a very bad thing.

For little money,make sure the head is as good as it can be. Skim 20 thou, open up the ports (carefully), port match the inlet manifold and head to the gasket. Leave a step on the exhaust.

Make sure the valves are lapped in properly. 32 mm TB is a good upgrade, may only be 2 mm but using Pi its a significant increase in area and the standard ECU can cope.

866 cam is handy, providing its fitted using a vernier or offset dowel. Don't assume the standard position is correct.

D

 

[shambolina]

use the 40mm tb and skim and port, consider a chip then

 

[Towsejames]

I'm here!!!



.



866 cam is handy, providing its fitted using a vernier or offset dowel. Don't assume the standard position is correct.



D

Okay so slightly confused about this, what we talking about an offset dowel? May come across slightly uneducated but I aren't sure what you mean?

 

[rallycinq]

Okay so slightly confused about this, what we talking about an offset dowel? May come across slightly uneducated but I aren't sure what you mean?

On the cam end where the sprocket mounts is a locating dowel. On a standard cam this ensures the timing marks on the sprocket line up.

With an 866 using the standard dowel and the standard timing marks may not get the best performance.

Once the cam is fitted using the standard dowel, check the timing to make sure that its right, if not, then buy an offset dowel that will move the timing to optimum.

D

 

[Towsejames]

Ah makes a lot more sense! Thank you for explaining will look into this

 

[blu73]

well rallycinq seems to have covered it mostly... nothing wrong at all there. All I would add is what you do tuning wise really depends on your goals. Is it just a cheap daily you want to pep up a bit, are you planning on keeping it longer term etc etc. There is alot you could do but whether the payoff of the effort is worth it depends on what you want from it etc etc.
Its not such a common swap as back in the day but just sticking a 1242 bottom end on makes a cinq great fun and its super cheap to do and easy as well. Everything stated above about port matching etc still applies, you could do that after to improve the 1242 further.

Possibilities are endless though - just depends on goals, budgets and the one everyone forgets... having the time to do said things. lol

 

[henseyseries3]

Don't get my wrong grant proved 1108s will make over 100hp n/a with the right headwork cam ect on his hillclimb/sprint car

But Ill stand by the most effective "cheap" mod you can do over a weekend is exactly what blu73 said
1242 bottom with your head on

 

[Towsejames]

1242 bottom? I assume you mean an 8v punto block with my head? Whats the difference between heads? The 1.1spi and the 1.2?

Thinking of getting all the little bits done to my 1.1 first. 40mm tb, decat, port and polish?

 

[blu73]

the head is the same, but if you get stuff done to your head then you should keep it. Also means if you stick the 1242 bottom end on it will go in with a fresh headgasket and stuff. If i was to just drop a 1242 in and use the head that came with it i would still recommend putting a new HG on it anyway.

If you get a 1.2 spi from a late P60 there is small chance it will have a 866 cam in it already, towards the end of production it seems fiat had spare 866 cams lying about and they went in the P60's. But you can just get a 866 to fit in yours when you get the stuff done to the head - I pretty sure Lecook has one for sale atm if you are looking for one.

 

[DRSIK]

Sparkys 40mm throttle bodies are brilliant

 

[Lecook]

Yes i do indeed have one left over.. i need to remove it from the engine thats in my shed yet though....

I also have a sparky 42mm p75 throttlebody and cannot reccomend it enough

 

[Towsejames]

I've got an 866 in already, made quite a nice difference. And ah I understand now, the next step will be a bigger block eventually. Doing all the small bits that can be transferred over. Getting the 40mm tb as soon as I get paid! Can't wait

 

[Towsejames]

Anyone know where I can get a 421 manifold?

 

[henseyseries3]

Anyone know where I can get a 421 manifold?

From supersprint if you have lots of money there used to be a cheaper option but I haven't seen them on eBay for a while

 

[henseyseries3]

Okay I lied apparently I wasn't looking hard enough

https://www.ebay.co.uk/itm/121357781875

https://www.ebay.co.uk/itm/220913391610

 

[blu73]

bear in mind them 421 are the length required for a 1242 - they hang very low on a 1108. You can run one but the manifold is the lowest thing on the car then and you risk bending/snapping it.
Supersprint do a 1108 421 which is shorter but then it won't fit if you get a 1242.