4 replies to this topic

[coople]

Hi, Just wondering how much power the standard z20let engine can take before you start running into internal problems. I have a gt28rsr turbo on my other car and have been thinking about fitting it to the vx. Anyone know of common problems and at what level of tune i.e. I know the fiat coupe 20vt engine can have problems with ring lands cracking above 300bhp. Yes I realise you would have to go to MMG stage 4 IC or charge cooler.

[SteveA]

Courtenay Sports web site has some good info on limits http://www.courtenay...s/info_162.html Basically going over 300bhp for LET needs pistons, over 320 steel rods are required. Should be good for 500bhp from there.

[danger7]

Hi, Standard Z20LET with a GT2871RS should make 320 bhp, BUT all things considered 280-285 bhp would be the limit, the restrictions are a standard piston heavy and outdated in comparison to the squeeze cast and much lighter skirted design of the Z20LEH - there is no cooling of the valve stems on inlet and there is no oil spray bar for cooling the underside of the pistons. The rods are good for upto 400 bhp (as tested already in a german speedster turbo with 40,000 kms) and the crank is very strong capable of 450-500 bhp. High engine temperatues are what kills the Z20LET and pushing the limits reduces engine life and I've seen many Z20LET's with burnt & holed pistons - Vmax has boxes full where maps have been created without sufficient piston cooling (fuel dumping) which has caused failures on track. I run a Z20LEH motor (standard) except I fitted all internals to a C20LET block with a GT2871RS which is Owen Developments modified and a Vmax manifold the boost is wound up to 1.4 bar (302 bhp) but 1.6 bar is possible (363 bhp) exhaust is a 79mm right through with a 100 cell cat. Charge cooled (Proalloy) and water injected (Aquamist). Pushing the Z20LET over 300 bhp will cause potential problems. Cheers Ian

[siztenboots]

iirc tms did a stage 5 , same turbo, on std internals , guys name was Iram. if you can get the air in without stupid boost levels and no det from heat then good

thread here

the LET based engines frequently run 350-400bhp with largely std internals (bar modded cams and head work to make more power for less boost, or less boost for the same power.... ie run cooler)

Its just the fact the engine is rammed in the back that causes heat issues lol

Mind you a set of Steel rods can be had for £300ish from the bay..... ok they are Chineese copies but still better than std robs, and aslong as you aren revving it to 9K or something silly they will be fine.


The Vauxsport forum covers some very comprehensive info for tuning the LET based engines

[Nev]

Give me a ring if you like Coople, my contact details are on my website in my footer.