Z20let/lel/ler Engine info

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Z20let/lel/ler Engine info

Postby 116 Steve B » 26 Jan 2011, 15:54

Some info on the Z20 series of engines ,may or may not be usefull

Z20LET/LEL/LER is rated good for 320hp!

Block is from the X20XEV engine, the pistons are Mahle Versions

Concerning difference from standard X20XEV, compared to ZLET, from what I've found out here are other engine parts and from what engine:

Cylinder head and ignition are from the Y22XE.
Piston rods are from the C20LET.
Exhaust valves are from the X30XE.
Intake manifold is from the X22XE.

Zlet piston:
Piston is cast from an Al-Si alloy. The compression reduction to 8.8 :1 has been achieved completely by recess (1) in the piston. This recess is arranged in the centre and ensures a compact combustion chamber shape.
The piston inner shape is optimised in terms of strength and adapted material cross-sections for the heat dissipation from the area of the piston head. The top land (2) is 6mm high, the first piston land is 5mm high and adapted to the increased mechanical and thermal load of the charged engine.
To improve the noise of the piston, the piston pin has been set off axis by 0.8mm towards the pressure side. The piston pin has a floating bearing and con-rod

Zlet piston rings
The first piston ring is designed as a ball type square ring from nitriding steel, with a height of 1.2mm. The second piston ring is selected to be a tapered groove compession ring, with a height of 1.5mm. The three-part oil scraper ring with a height of 2.5mm

Stock Turbocharger is a KKK K04 good for up to 250HP-260HP which equates to arround 190KW with PH2 supporting mods...
(Common high Boost failures on these turbo's are cracking of the wategate seat and exhaust manifold)

Cars with PH3 and PH4 KKK K04 Turbos have managed to break the 300HP / 220KW barrier...

To reach the 350HP mark you will need a PH5 conversion with a Garrett Ball Bearing GT series Turbo like the GT28RS.

The Ecotec head is of a very narrow design due to the steeper valve angles used. The Exhaust valve has the steepest angle of 23 degrees and the inlet is 13 degrees. Those angles have a huge effect on the engine chacteristics giving it huge torque at the expense of top end power. The 29mm inlet valves are slightly smaler than the XE's with the 32mm exhaust valves being the same size. The engine is designed to rev till 7000rpm but with a set of decent conrod bolts it can safely be revved to 7750rpm...

Common engine failures:

Melted Piston no. 1 or 2 due to running lean.

Cracked ringlands on pistons due to detonation which eventually leads to the piston disintergrating will result in destroyed bottom end with a hole in the block.

Conrod failure also due to detonation will result in destroyed bottom end with a hole in the block.

For making over 300HP a decent set of Forged Pistons and Steel Conrods are recomended such as Wiseco Pistons and Eagle Rods
116 Steve B
Posts: 31
Joined: 10 Jul 2009, 16:50
Location: Waiuku, North Island

Re: Z20let/lel/ler Engine info

Postby 127 Gordo » 26 Jan 2011, 20:54

If the outlet to the turbo' is similar to the OEM LET mounting flange position, melted pistons may also be due to it running hotter than the other cylinders due to heat soak.
127 Gordo
Posts: 547
Joined: 05 Sep 2009, 18:35
Location: Waitakere, Auckland

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