S16 1.8 What Power Is It And Is It Worth Fitting?

[Nathan 0]

I want to build a quick 205 as my 1.6 is in need of a new engine, now I have a 1.8 s16 engine that I believe will fit quite easily however it doesn't seem very powerful for a 1.8 16v engine (112bhp I think, but I'm not sure).

 

Now is it worth tuning this lump and sticking it in my car? Or am I better off spending my cash on different engine (maybe a 2.0)?

[Hilgie 16 2 Cars]

It depends on the price they want for the engine, but if it's cheap it's worth to fit. You'll have more power than the 1.6 and the 1.8-16V has good characteristics.

[Sandy 191]

The inlet manifold and ports are a bit small and restrictive and the cams are mild, they clearly went to alot of trouble to keep the power down! I swapped the cams and exh manifold for gti6 ones and ran TB's on mine and it's a very lively engine, revvier and more responsive than the Mi16. Sort the ports out and raise the CR a bit for an excellent engine. There was a a hillclimb (overbored to 84mm) one that gave 240bhp down here, but not sure where it is now. It's a great sounding engine with the GTi6 cams (compared to the Mi), that's my main reason for loving it.

[James_m 0]

Does an MI16 head bolt straight on? what sort of compression ratio would it make?

[Sandy 191]

Mi16 head would be a backward step, the chambers are larger, the ports are arguably too big and you'll have the oil drainage issue. A GTi6 head or porting the XU7J4 or XU10J4 heads makes more sense.

[James_m 0]

The 10J4 head is the same though isnt it? im just thinking it would make a cheap bottom end for existing Mi16 owners, i.e me(though engine management is always going to be the issue with that). Plus does'nt the Gti6 head have major issues with warpage and the corresponding tapping from the guides?

[Sandy 191]

No, the 10J4 ports are cast differently (less restricted). The Mi16 chambers are about 6cc bigger, so the CR would be far too low for NA. I'm not aware of any problems with the GTi6 head. The valve sizes are slightly different, but not badly and the ports come pretty nicely tidied up as standard, not as good as a proper job of course, but tidier than the Mi comes.

[James_m 0]

Sandy, any idea what the chamber volume is on the XU7JP4 head?

 

Cheers James.

[Mandic 0]

No, the 10J4 ports are cast differently (less restricted). The Mi16 chambers are about 6cc bigger

 

So You are saying XU9J4 and XU10J4 have different head ports?

 

Cheers

 

Ziga

[James_R 3]

GTi-6 chamber's 36cc Mi's are 40ish cc from a search

[Sandy 191]

I measured it at 36.5cc on the one Shillaber did for me a while back, but there was some chamber material removed and a cleaning skim.

 

The 1.9 and early 2.0 16v heads are largely the same, but the later (post 1996 roughly) 1.8 and 2.0 16v heads are much different. The 1.8 head has inlet ports cast very badly and a much smaller lotus flower style cross section, the 2.0 head (except GTi6) has bigger inlet ports but is still pretty roughly cast. The GTi6 is bigger again on the inlet side (arguably too big around the valve guide to throat) and has slightly blended throats and three angle seats. The GTi6 valve sizes are different to the other heads, slightly smaller inlet and slightly larger exhaust.

For a cheap road head to work well without spending, the GTi6 make the most sense, but for extensively modifying (especially for the 1.8) the base 1.8 and 2.0 heads make more sense. There's more material to work with which gives more options on port shape and the cam clearance is much greater. Beware later L4 heads have an EGR port on the end, which needs blocking.