Tuning highly tuning the 1242 8v

[Lecook]

Hiya guys just having a think about how highly you can tune a 1242 before there's nothing left to do, I know that there is endless little things you can do but I was focusing on the mods that will see good gains

So far I've come up with

Gsr induction with bmc cda
40mm throttle body
Triple angled valve seats
Uno 45 inlet
Heavy head skim
Port match on the exhaust and inlet
866 cam
lighter flywheel
4-2-1 exhaust mani


Is there anything that I've missed that'll give me any more noticeable gains??

Also does anyone know what sort of power output/torque would I be looking at with all of the above??

Cheers in advance

Lee

 

[woj]

Is there anything that I've missed that'll give me any more noticeable gains??

A turbo?

 

[Lecook]

Yea, that sure would give bigger gains but I was thinking just N/A engine mods rather then having to change management wiring/loom ect, how far have they been taken without loosing too much reliability

Cheers
Lee

 

[Brooky]

Going mpi should be your first priority on any tuned engine!!

The three mods i would concentrate on is:

MPI
ECU (a good remap after all mods complete of aftermarket)
Cam (something better that a punto cam) and dont forget an adjustable pulley

Then stuff like custom inlet if you can as arc found the p75 mani is poop, get someone to port the head properly with a flow bench and get some bigger valves in there

 

[woj]

Well, the thing is, reliability depends on the quliaty of your tuning work. I am about to close 40kkm with my turbo, the most recent (today ) semi serious thing I had to do was exhaust mounting rubbers that were on the edge of giving their life away.

Re. management, if you want serious gains, even n/a, you have to at remap your ECU after any more serious mechanical mods, no way around it I am afraid

 

[Lecook]

I know with mpi you just splice the inj wires giving you 4 firing injectors without having to do too much modding of the loom but surely there's a better way around it?? Could you use the 1242 mpi head from a mk2 punto?? Or is it really a p75 head you would recommend??

Also is there a bigger inj u could use in the spi set up that would give you any noticeable gain??

 

[Brooky]

A better way round splicing...... aftermarket and loom time

Dont think there are any bigger injectors for the spi.
I sure a 'highly' tuned spi car will end up the same way as fingers' tub, a big hole in the piston due to crappy spi fuel distribution

Nitranes race car is mpi....you know it makes sence

 

[Lecook]

As far as a remap goes obviously with the spi ecu u have to have the eprom made up with a suitable map and I assume u cannot map a eprom more than once?? Is that why u say go for the mpi set up?? I've also read that the mpi ecus aren't the best aswell

Lee

 

[Brooky]

I dont know anything about remapping sorry.

I used to have an Avanti eprom chip and a C&B 280 cam. They came out of the written off rally car i bought, moved on to megasquirt now

 

[Lecook]

Although it makes sense to go the aftermarket ecu route I was thinking of how to do it without making a meal of the loom lol, if I were to go down that route surely it would be better to go 16v, the problem I have is this, I have a 1242 8v sat in my seicento that just needs the 866cam re-shimming it has that along with a lightened flywheel, totally rebuilt head with heavy skim, brand new cambelt and clutch, I have a gsr and bmc sat on my current 1108 that I can use, I just have the dilema of whether to carry on with the 8v or sell it all and get myself a 16v engine to play with/learn on I was going to send the spi tb away to be bored out to 40mm and see what sort of gains I would get over the setup I have now(standard 1108 with gsr+bmc and janspeed) to put on the 1242 without having to spend silly amounts of cash

Lee

EDIT: my knowlage of ecu building/mapping is limited and I don't really know anyone round my area that could help me out to build/map a ecu, I wouldn't want to spend the money on aftermarket and it end up being nothing more than a expensive coaster in my shed

 

[Brooky]

Well make your mind up weather your going 8v or 16v

I was going to go 16v, but i like tuning, and the 8v is abit more tune-able and i had aload of 8v bits kicking about like the vernier pulley and exhaust manifold

 

[woj]

I think, a tiny bit, is that you are asking yourself the wrong questions. They should be:

- are you after power or reliability?

- every day drive or track days?

- moderate or high budget?

- what is your knowledge and skill you can put into the project, what do you have to delegate?

- do you want to learn, or just to have the thing done?

I can go on like this till the sun gets up again, but I eventually need to sleep

 

[Brooky]

:yeahthat:

'highly tuning' to me would be a race spec engine......very expensive, i know, im doing it

 

[Lecook]

I would rather stay 8v if I was honest as I've got the base for it already and I've already spent a a bit on it

As far as power or reliability goes I'm after a happy medium I don't want to go tub as yet(I have toyed with the idea) as the car is my daily, as far as budget goes I want to spend as little as possible lol, I'm happy to spend money to get the job done properly

As far as what I can put in goes, I am happy to do anything mechanical, I don't have access or know how to por/mill/or turn anything but I have some friends that are engineers/fabricators/welders ect

My brain is a sponge as far as learning goes, I love learning how to do things and I enjoy doing things to a high standard (hence why I sometimes seem to ask silly questions) I'd like to do as much as I can myself to keep costs down and to learn new things but obviously some things ill have to pay to have done

Lee

 

[Brooky]

Go down to your nearest custom exhaust place, get some scrap 2" pipe and get your welder/fabby friends to make you a bigger bob and chop your gsr hose down abit.

No point enlarging the throttle to 40mm but having the induction system with a smaller diameter. I carnt remember the inlet of the bob bu it's deffinately less than 40mm
Look a nitranes/rallycinq/jatkinson(used to be mine) induction systems for examples, I like rallycinqs

 

[Lecook]

Ok cool I'll see what I can sort on the inlet side of things I've just started to learn to
Weld so I suppose it'll be a good place to start

I'll get a quote on the b enlarging as I've nOt had any luck with anyone in the classifieds I think I'll nEed to find a 40mm butterfly though and I might see if I can borrow a die grinder to have a go myself

 

[Lecook]

Ok so I've been looking at options and I'm swaying towards the mpi turbo route

Just off the top of my head these are the basic parts I'm thinking ill need

I have a mk2punto 1242 mpi bottom end with 1108 spi head (am I right in thinking its the same block as the p75)

As a start this is the rough list I have compiled

1242 16v pistons and rods (to lower compression for the turbo also I understand the they are lighter than the 8v items)

Decomp plate, is this a necessity or will the lower comp of the 16v pistons be enough?? I'd like to avoid if possible without having to get forged pistons

Turbo, I understand they are found on the older astra 1.7 diesels and some of the saab 2.0 engines (more reading to be done)

Aftermarket or piggyback ecu ?? I've read lots on megasquirt but still have no clue (this is going to be something I will have to learn whilst building the engine)from what I understand I'd like to go piggyback rather then the full aftermarket ecu

Obviously mpi head, ecu, loom ect ( posible candidates??? I know p75 head and loom are an option but can I use a mk2 punto mpi unit?? Maybe issues with stud patterns on inlet/exhaust when it comes to turbo mani as I know the pmk2 had a manicat)

I've defiantly forgotten a fair few things oil cooler, intercooler, fuel pump, will I need a fpr??.

I know this info is all over the forum in dribs and drabs but I'm trying to get as much info in one place as possible

Cheers

Lee

 

[Brooky]

200mm clutch assembly, decent rubber(you were on about tempra wheels wernt you) and a LSD to get the power down.
Custom exhaust.....2" or bigger
3bar pump

 

[Lecook]

Clutch and flywheel from a 1.4 16v iirc I am toying with the tempra wheels but I have a set of abarths if all else fails exhaust aint too much of a problem as ill make one up when the conversion is under way, I'm just looking at engine at the moment as there is still lots to learn currently reading the turboing burple thread mucho help and now looking at the mf2?? Is that still available or is there an newer similar designed one on the market at the moment ?? Any more advice on who makes them to aid tracking one down

Cheers again

Lee

 

[ycming]

highly tune and spending as little as possible don't go well together.

I think what you done is "good" if you want to make any more vast improvement it will start to cost! Even a C&B cam is not cheap, easily double what you have spent already.

Just spend time on building up your engine and make sure everything is right, that be your best bet!

Ming