Thank you for the link to the cams
I’m aware the boost controller won’t give me any extra power, but I need the possibility to lower the boost
You might get ECU errors for underboost.
it’s true the limit for hx221w is about 250 for diesel, but should deliver flow up to 300 on petrol.. also, don’t wanna go too big due to spool up time.. was recommended this particular one by a serious and experienced tuner, that’s why I chose it
you don’t think it’s a good choice?
As a rule of thumb diesels use much smaller turbos that petrol engine. A loose approximation a turbo off a 3 liter diesel can be used on a 1.5 liter petrol (it's because petrol engine have a lot more rev range (extra 2k rpm), and also work under vacuum.
Power will be related to mass of air flowed though the engine.
If you don't already have it.. or can get it really cheap i would try something already tested and proven (and cheap) like the TD04.
Also i think that Holset, only has oil cooling?... i would avoid that at all costs. the T-jet only has 3 liters of oil, and at those temperatures and forces, the oil will degrade really fast.
If money isn't an issue, you could also get a increased oil capacity oil pan
TCM has them.
Will provide some buffer to oil degrading really fast.
If it’s possible to achieve 340hp with a stock head, wouldn’t it be possible for me to get 250 from a stock head?
But agree, but be preferable with cams.. you think those you linked would be plug and play?
The head itself isn't the problem... the cams and cam timing will improve things; max power...maybe low rpm pick-up.
The NA cams will provide some more lift and some more duration(some overlap as well).
The result of the NA cams, compared to the stock 120t-jet will be the turbo will have to produce less boost for the same amount of power. If the turbo works in the more efficient zone of it's flow map, the air will be heated less, colder air => more power.
The net result will be more power with less stress on the turbo (also less chances of hoses popping off or splitting)
I think the cams i posted will work,
BUT make sure it comes with the cams (it states they are from a NA 1.4 Bravo, and the pictures look right to me). bonus comes with another cylinder head (but without valves)... you could clean and port it a bit and just have it at hand for when/if you need to go into the engine.
I mean if i was going for big power, and was willing to spend like 2k for doing that... i would stay away from going into the engine for the rods and pistons, at least until it blows up
); but seriously the t-jet can take a lot with the stock internals...
when it blows up, i'd search for the cause... at that point you can actually see what the problem was... i'd say a piston will melt even if it was forged, and a rod will probably bend from detonation. The stock and the forget aftermarket ones will do the same.
Also are you sure the t-jets can easily take H rods?
i saw some post where they needed to grind quite a lot from the cylinder base in order to make them fit
The problems will be heat, oil degradation, correct tuning, stable fuel pressure and flow. Also there are no colder spark plugs available. As far as i know there are some racing spark plugs that are colder (really expensive for a maintenance item), and i think
BRISK also has some "Silver" that might work, but some people say they get clocged up if not driven hard enough
BTW with the 380 cc injectors you don't want to go over 250hp, at that power they should be around 90-95% duty cycle. Maybe you should get something bigger; 450cc will take you to 280hp at 90% duty..
