Z18xe/x18xe1 technical.....

[Mxcrazy]

I have done a fair anount of research on the engines. A lot of the info is spread amongst other threads and topics, kind of hard to find.

As the engine is becoming more popular for conversions, and also tuning in thier original cars, can we have a thread that concentates on it specifically?

My prospective build is as follows:

z18xe/x18xe1 engine.

Head:
ported, work on runners, short side radius and combustion chambers.
piper 285 cams purchased (from x14/16xe)
spring kit....i bought a set for the 14/16xe but spring caps are to suit 6mm valves/collets. I am looking in to corsa vxr spring kits to suit 5mm valves....any more info?
sticking with hydraulic lifters.

Intake:
big bang r1 throttle bodies and airbox, utilising variable length intake set up and R1 air filter, to be fed from bonnet vent.
Custom inlet manifold to suit.
toyota 2zz injectors (to suit r1 bodies and fuel rail)

management:
Emerald k3 system, wired to run servo for variable intake tract length based on target rpm, + wideband lambda sensor for initial base mapping before dyno work.

exhaust:
Tony law full system from 16xe nova, 14/16xe manifold, ports line up using top manifold bolt holes, lowers need to be elongated to fit studs on head.

internals:
stock crank
z18xer pistons and rods, pistons use valve cut outs and a domed top for more compression. This set up i have seen mentioned, but no hard cold facts about. Apparently it results in 11.7:1 compression +/-.
arp rod bolts (m9 type)

target red line would be 7.5k rpm, hence only using quite mild cams. The bottom end once balanced should cope here quite well.

lightweight flywheel and h/d clutch, mated to a Quaife f13 sccr gearkit/box with a 3.9:1 final drive.

If anyone else has any useful information. Hints, tips, experience or otherwise, please share.

I Believe people are a bit scared to use/try this engine because of the lack of information. It'd be nice to open it up.

basic limitations seem to be with Cams, ie, clearance with pistons, i am hoping the xer Pistons will be an easy way of removing this limitation. For those wanting to not go too high with compression it would be far easier to remove the dome than make the cut outs i am sure.

as above, lets try and hear everything we can about these motors.

Thanks, Ollie.

[_Tomiboy]

If you remove the dome from the pistons you will have problems. I removed 1mm from the piston top, around the dome, and 0,5mm from the dome. Now the weakest pont is 3,75mm the piston top, it is not so much, but it works with 11,7 CR. If you remove the complete dome, that will be sooner or later bad.
For lightweight flywheel you can use the flat type from c16se.
7500 rpm with ARP rod bolts works fine. I have no experience with higher revs.
I used 4,18 and 4,29 final drive. In the winter i will change for 4,53.

[Mxcrazy]

Your engine is a bit of a hybrid if i remember correctly Tomi? Is that why you removed material?

Can you confirm the z18xer pistons/rods will work in place of the z18xe pistons rods? Or are they different heights?

[_Tomiboy]

Yes you are correct, but i had also z18xe engine, this was standard, i had only 4-2-1 exhaust manifold.
The height between piston top and gudeon pin center is different. 24-26,1mm

[Mxcrazy]

I did some measuring tonight.

z18xe/x18xe1 crown (from squish area) to pin centre 24.1mm
z18xer 25.4mm

so 1.3mm difference.

i backed this up by comparing pistons side by side, ring grooves and pin centres match but crown measured 1.3mm taller too.

I am thinking xer pistons/rods with a 1.3mm decompression type plate. The decomp plate would be cheaper than piston mods for valve clearance and you still gain compression.

[_Tomiboy]

Cometic multy layer gasket? Up to 0.098" 136$, but you can use it more times.

[Mxcrazy]

I am getting a price on a decompression type plate for comparison also.

i'd like to build a few engine in different states of tune, maybe on carbs also, see what works or not and what gains can be made. I dont have the ££ for that though.

[_Tomiboy]

That is the reason why i use c20ne ecu and loom. It is 10 times cheaper than standalone ecu, and many tuners can write it.
For 16v you can use the c20xe M2.8 management, there is also many options, to map it.

[Mxcrazy]

Thats interesting, i didnt know that.

i have gone for the emerald because it was too cheap to turn down and offers extra functions that will be handy to me.

A decompression plate will be about £105 delivered in 1.2mm -1.4mm.

[_Tomiboy]

That is heavy price for a laser cutted piece of plate.

[Mxcrazy]

Yes and no, id rather pay that then try and make one myself. They obviously know what they are doing with them and the right material to use etc.

If someone can do it cheaper i am all ears though. Anything to keep costs down is a bonus.

[jimbob-mcgrew]

just incase you didnt know.
from what ive been told, the trickiest bit of installing an x18xe1 is the fuel side.

the engine has no return line, and in its default setup, the in-tank pump controls its output levels accordingly.

to remedy this issue when fitting into another car ... an adjustable pressure regulator, with a gauge, needs to be fitted into the fuel line, and set up just right, for it to fuel properly.

[Mxcrazy]

Thanks for the info, mine is going on to throttle bodies so i wont have that problem with the stock engine, but its worth noting for sure.

I can 99% confirm that Piper cams spring kit for a Corsa VXR will work in these engines. Its been used up to 8000 rpm in the VXR engines with no problems. It can cope with up to 12mm lift but thats pushing it. I am just going to run pipers 285 cams for the x14/16 engines with 10mm lift and 2000-7000 power band. The next cams 'up' have a powerband of 3000/7800 and 11.5mm lift on the intake, 11mm on exhaust.

Revving this engine to 7800+ with the stroke it has and using stock components will be pushing your luck. I plan to have a soft rev limit at 7500 and 7750 hard cut.

I had thought about de-stroking it, but that takes away from the fact this engine should make good power and torque over a wide rpm range. With my plan of 11.5-12:1 compression, mid spec cams, non over sized throttle bodies and not revving the crap out of it, it should work pretty good. Coupled with the Quaife sscr f13 in a light car it should go suitably well.

[totalnova]

What brand of cams are you going to use Mxcrazy? ive seen catcams are a decent price on LMF website

[Mxcrazy]

Sorry, i should have said. Piper cams, pulleys and spring kits.

[Mxcrazy]

Just an info follow up on here because it may be useful in the future to somebody.

Where I am at with the z18xe is as follows.

Z18xe block, crank and head.
z18xer polished and weight matched rods.
z18xer weight matched and moly coated pistons.
1.5mm decomp plate (only needs to be 1.2mm which is an option from ferriday, i need to deck my block) to suit taller xer pistons. (To give 1-1.1mm quench clearance)
z18xer valves (longer and less recessed on chamber side for more compression) and xer solid lifters (need lash caps, available from Kent auto developments, size depends on cam base circle diameter)
piper bp300m cams from 14/16xe (290 inlet, 280 exhaust) 34mm base circle.
piper corsa vxr valve spring kit

cc-ing the head with the xer valves and a plastercene bung instead of spark plug gave me 40.5cc volume.

With those cams and the xer pistons (with oem cut outs) i got 2.6mm inlet valve to piston clearance minimum and 3.8mm on the exhaust side.

By decking the block 0.3mm (with my 1.5mm decomp plate) to get 1-1.1mm quench (piston to head clearance) I am still left with 0.7mm i can skim the head by to increase compression and still have at least 1.5mm piston to valve clearance on the inlet. (Head gasket will squash from 0.4mm to 0.3mm once torqued down tight if you wondered where the other 0.1mm went from 2.6mm pvc to 1.5mm pvc).


I have to do some more measurements but i am looking in the range of 11.5-11.8:1 compression once block decked and head skimmed with good clearance, with pretty ideal quench clearance.

[gunny]

Did you ever finish this build? I'm interested in the results