1.7 tuning question

[laney1812]

few questions to ask

1. know its unusual to ask but can a 1.6 zetec-se head be fitted onto a 1.7 block ?? just curious

2. do you recommend skimming 1.7 head to raise compression if so how how much is safe due to valve and piston clearence..

3. thinking of fitting throttle bodies .. so im thinking of running a unichip piggyback ecu .. anyone done this or know if run vct ok ..

4. is it better to tune a 1.7 with vct or remove it and if removing it whats best way to do it

 

[laney1812]

anyone answers to above

 

[Ginger Tom]

1. No there is an extra leak off gallery on the 1.7 block and head that the other sigma engines don't have

2. Yes you can do that but it is safer to change the pistons for high compression items

3. If your using a piggyback ecu the standard one is retained on the car and this will drive the vct and the piggyback will adjust the fuelling

4. It depends on what you want from the engine, a lot of engine builders, that I know, like to remove the vct as it makes them easier to map

 

[laney1812]

thanks for that info tom...

what safe compression for standard pistons as im talking only a mild skim...
also if i change my cams there wont be any valve piston contact problems will there??

hmmm its a tuffy decision.

im tempted by 4-2-1 manifold + sport cat back system..
cams maybe from lightening motorsport
head skim and port and polish maybe better angle seats aswell...
either lightening motorsport inlet or fabricate own to similar style.. mondeo throttle body ported and matched to inlet..


but regards to mapping would it be better to just go ie puma speed or somewhere and get one of their maps orr get a piggyback ecu and remap especially for car??

 

[PumaNoob]

A mild skim is about 0.2mm, so really wouldn't significantly adjust compression ratio, I'd guess it would toke it from 10.3:1 up to 10.5:1, you wouldn't really notice any power increase there. You'd have to take at least 0.5mm off for any significant difference, but then you are reducing the amount of lift available on cams, or the amount of advance you can run on the VCT.

I think the VCT should always be retained, it will always give a broader power range & better drivability, but I'm not sure at what RPM it might become unstable.

 

[laney1812]

hmmm ok cheers for the input