8 replies to this topic

[hulsmeier]

Hi All,

I would like to tune my engine. I'm setting my sights on modifying the head; ported and 1.5 rockers. I also want to go with the lcb, a better cam and timing gear, and a lightened flywheel.
I've got the Vizards yellow bible, and read a lot of this forum the last few months. I was hoping people could point me in the right direction. 
Its a 94 spi, and I'd like to keep the cylinder bores standard. 

What would be the best cam to go for?
With the cylinder head modifications, how much would it cost to have some one do the 3 angle valve modification?

Would the results from doing the porting myself be worthwhile?

Would it be worth having larger valves if I am keeping the cylinder bores the same volume?

What lcb should I go for given all of the above modifications?

Thank you in advance.

 

[mikespicooper]

use the mdm274 kent cams cam with the s12 timing gears to set to the correct timing.

port the head lightly and if on badget use rimflo valves.

the maniflow exhaust lcb manifold for the injected mini is the best option.

use solid 1.5-1 rockers not the roller tip ones changing the valve lift gear may result in loss of power tha increasing it.....

arp studs and bolts all round the engine and convert the engine to coilpack ignition and fit the crankshaft position sensor to the front of the engine to be able to fit a pre-verto clutch which has better grip!

DO buy a k&n in standard air filter element or an inductio kit!!!!

[Badboytunes]

Our SPI has big balve head, SW5 cam, ported and polished head and returned 70bhp on the dyno.

 

Its drives nice and feels quite nippy.

[iMurray]

Bad boy is that with the standard injection system?

[felixy69]

What computer computer are you you thinking of running?

[felixy69]

What computer computer are you you thinking of running?

[welshdan]

Do not fit a pre verto clutch setup. It is not required. This will add a lot of cost and complicate things.

Do you plan on removing the engine for these mods? Some very worthwhile mods can be done with the engine insitu.

I f on a budget i would look at getting a decent second hand worked head to refurb, or a used big valve head such as the mg metro item. I would clean up the chambers, romove the guide boss and clean up the ports. I would consider using rimflow valves but they are a lot of money for little gain.
I would change guides, have the valve seats recut, and have the head skimmed to raise the compression ratio

I would fit some 1.5 roller rockers

A decent injection lcb abd exhaust system.

If you were to remove the engine i would also consider uprating the cam to one of the aforementioned. Re newing the diff pin would also be benifitial, to an uprated item. Also a new ap racing fast road clutch plate would do the trick. I would also consider new bottom.ebd bearings, obviously everything would need to be checked over

I believe that a certain metro k series ecu can be used on the spi, though my spi k.owelage is limited

The insitu mods mentioned can yield a very good cost/ performance upgrade over standard. These mods could be retained if you decide to change the cam/ overbore etc at a later date

[Badboytunes]

Bad boy is that with the standard injection system?

 

 

Yup, and it breathes through a K&N filter.

[hulsmeier]

Sorry I haven't replied sooner. Thank you all for the replies. 

The idea was to stick to a budget, to remove the engine over the winter and upgrade the cam, rockers, modify the cylinder head, lighten the flywheel and add the vernier timing gear. Also, add a lcb.

How much of power gain would I see from the above tuning? I think I'd like to try the head work myself, but I want to make sure the gains are gonna be worthwhile.
Where could I find a decent second hand spi head thats been ported and modified?
I'd also be keeping the same ECU. 

Thanks again.