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What can be causing High EMP

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Im interested to learn what could be causing my 2jzge vvti setup to create high exhaust manifold pressures.

current setup is as follows

2jzge vvti, 10:1 comp CP pistons, Spool ibeam rods, pocket ported head with Kelford 272/278 cams, kelford springs and retainers. GSC valves stock size.

601kw (dynopack) @22psi on E85 . more boost = less power emp= 1.5x boost generally from the logs i can find

manifold is something I made and is 32NB Sch40 pipe, twin scroll.

turbo is a MSE 6367 with 16cm housing.

We recently went from a 14cm housing to a 16cm housing to try and alleviate the hi EMP but it made pretty much no difference.

what im wanting to try and understand is, are there tune related things that can cause this situation like cam timing or anything else i can look at??

emp is measured at turbine housing as close to the flange as possible.

If this is just a limitation of the setup then so be it but turbo provider says its weird that changing the housing did nothing.



Surprised no-one's commented who has experience of the engine.

You don't mention the exhaust system - diameter, ruouting, and the mufflers/silencers used. We have quite strict sound limits to work around in NZ, and that will also be contributing to the EMP, as that's measuring the total pressure.

It would probably help if you could provide some pressure values after the turbine housing, as that's also a significant factor, and pic's of the exhaust, etc, may be helpful.

I'm not sure how I missed this post, sorry about that.

First off, while you've posed a question related to a concern about what you feel are high exhaust pressures, it sounds like the setup is generally working really well. You've stated power is not lacking, so it sounds like you've met your goal there. It likely spools great with that compression and drive pressure.

I'm a fan of compression so I like the 10:1 choice for use with E85. Higher compression will result in higher exhaust temps and pressures all else equal at a given boost level, but you'll get more power too. Are you feeling the exhaust pressure level seems high for the boost level, high for the power level, just high for your liking in general?

Do you have a turbine flow chart you can post? I've not heard of this turbo.

To answer your specific other question, yes cam design and phasing, degreeing are big factors in exhaust heat and pressure. Ignition timing will also impact exhaust temp and pressure.

Lambda of course as well. I've found some folks going over rich on E85 have generated more exhaust mass flow without making more power, so I'd be curious to hear if you tinkered with it on the dyno.

Again, it really doesn't sound like anything has not been done well based on the info you've provided, but I like the curiosity and interest in further optimization!

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