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X20Xev Inlet Manifold

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#1 Mk3vr6/24v



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Posted 13 November 2017 - 08:33 PM

Hi just a quick question for the z20let folk
Has any one of you lot messed about with a xev inlet with the flaps inside?
Im after some more low end torque off boost
Little back ground
The engine is Standard as far as I know,I totally forgot to check under the pistons but from above look same as leh pistons. I did the head gasket and used the head of the leh engine Ive got to save time waiting for machine shop
Multi angle valve seats and cleaned up exhaust ports, standard turbo
Ive deglazed the bores,not burning hardly any oil now if any as the dip stick reading not changed and using shell 5w30
At the min Im doing all the brake pipes and bushes and suspension so the Zafira is off road and got a little time to mess with the manifold


Omg its been a right ball ache to get this far

#2 Nev


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Posted 14 November 2017 - 07:37 AM

My bet is that the XEV inlet manifold is already tuned for good low end torque. Maybe you could narrow the tubes or some such, but I think you'd be likely to cause more problems than cure them. You probably know this already, but to increase low end torque the general principle is to narrow the tubes to increase flow speed, however doing this in practice is hard to do.


BTW, the Z20LET inlet port form factor is very similar (maybe identical) to the XEV, so you could try installing/looking at a Z20LET inlet manifold instead as the Z20LET "might" be tuned for more pre-turbo spool torque.


GL, sounds interesting.

Edited by Nev, 14 November 2017 - 07:38 AM.

#3 ayresyy



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Posted 14 November 2017 - 07:57 AM

 I guess the 'theory' of the XEV inlet is correct. Long runners for low RPM then the flap opens at higher RPM and shortens the runners. It is vacuum operated though so that could be an issue for a boosted engine. You would also need a way of operating the control valve at the correct RPM. I do suspect the XEV manifold is tuned more for N/A induction rather than forced induction, but as far as I know it's not been tried. The inlet ports do match so who knows?

Edited by ayresyy, 14 November 2017 - 07:57 AM.

#4 Mk3vr6/24v



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Posted 14 November 2017 - 05:50 PM

Cheers for the replies chaps
Thats the top half of the manifold Ive not got round to the other bit yet
Ive got two well will try 2 options
1, is use two one way valves, first one on the inlet vacuum so with engine started the vac will
Close the butterflies making the inlet trac length long and keep them closed with part throttle and the second one way valve from the turbo and maybe a adjustable restrictor
So the boost will open the butterflies in the manifold
If that makes sense to you all
2 is to use the solenoid on the inlet, activated with the pressure switch from the water injection
I can only see it causing a drop in power on the top end but I dont really go up there unless I break traction in the rain

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