211Ratsbud

iTrader: (1)

All the more reason to investigate. Please share your results.

boostedup

Ok so I just had a thought, the throttle body is a drive by wire unit off an ls1 given this engine and throttle body was not designed for boost, could the boost be starting to push it closed?

211Ratsbud

iTrader: (1)

those are boosted regularly. It wouldn't be my first suspect. What unit is it? An OEM part or aftermarket? Your BOV would start to vent if you closed throttle enough to lower boost and it will even open with less differential in other circumstances. Is that something you can detect? (Leaking at wot) Actually this is why I suggest the BOV test above.

edited as I was making no bake cookies .. apparently making no sense either lol

boostedup

Yeh you have a point there but if the throttle was closing rather than limiting boost by way of an intake blockage which would cause the differential and hence the BOV to open, it could be just reducing engine load and exhaust gases being produced and have equal pressure across the throttle plate? ( I am probably clutching at straws here)
its an oem TB.
The only parts i have supplied is the intercooler and the throttle body. The throttle body was never used before and the intercooler has been used on the previous set up.
Point to mention here, the previous set up had a similar issue only ran to 40psi on an fp3794, made 790hp on a hub Dyno. Completely different set up tho, different manifold, turbo, gate, intake, TB. Has had engine build since then too. Had a full exhaust then, @35psi boost was seeing 54psi in header and 15psi in the exhaust so I put it down to the exhaust being to small. Does seem a little odd to have such a similar problem the only thing common is the intercooler but with a 2psi pressure drop across it thats unlikely??

hutch959

iTrader: (18)

thats a itty bitty I/C for that turbo

boostedup

Yeh true but 2psi is 2psi or am I missing something?

LetsGetThisDone

iTrader: (1)

It could still be limiting power and is far less than ideal. You're dealing with an odd issue, and the mix match of parts certainly isn't helping things.

boostedup

So I have some more data for this issue.
exhaust map max is 44-51psi when max boost is 43-44psi, variation is due to altering cam timing. Point to note max power was 579kw with exhaust map @51. Altering cam timing did not affect the boost it would make.
A bolt was put in the gate to stop it opening so this boost is the max the turbo will make at present, definitely nothing coming out of the gate.
Air temp in the Dyno room would have been around 100f and max intake temp got up to 131f.
max pressure drop across intercooler is 2-3psi.
Throttle body is definitely opening 100% and ecu is only using 40% of the a available output current to hold it open. Everything has been pulled off and pressure tested.
So, any ideas??

240Z TwinTurbo

iTrader: (25)

Ideally you could use a turbo speed sensor and that would tell you everything assuming FP has compressor maps available. Your EGBP:Boost is low so that would indicate you don't have a restriction pre turbo. Have you pulled the compressor housing to physically verify you have a Super 99? What fuel are you using, what AFR are you targeting and what timing are you running?

boostedup

the turbo is actually the new 105.68 its brand new, I am not doing the tuning so I don't know the exact timing he is using but the tuner is one of the best in Australia for tuning Evos and has built some mega power evos, his is making 1300whp, so I assume the issue isn't with the tune, its on E85.
they have an old gt42 set up lying arounf the workshop they are going to throw on there to see what it does, the other thought was to just throw some NOS at it and see what happens.
funny thing is,, all the numbers and testing seems perfect, it just cant make more boost and power seems to be low although tuner thinks its making good power on his dyno for that boost level, from what I see on youtube it seems to be low compared to what you guys in the US re getting but im not sure if that's a dyno calibration thing or not.
something is preventing it from making more boost, that same thing could also be limiting power.

Evo8cy

Ι see that by changing the dialing combo, you have achieved a bit higher boost, from 40 to 43 psi. The cam dialing combo, affects greatly the dynamic compression of an engine, which in turn affects power curve and peak tq/hp. It does not affect the amount of peak boost a setup can reach but it does affect the wgdc of it. Observe to see if there is any fluctuation in boost.



Since you have checked and re-checked everything and everything does seem in order including engine being built right and it is the healthiest and most efficient it could be, I have a couple of suggestions. Remove the boost control system completely including the gate, block off things, and allow the gasses to exit through a short exhaust pipe without any restriction on it.


Next would be to borrow and change the turbo to something of similar size, which is on another similar setup that already makes say 55psi.




Also bear in mind that 580kw is around 780whp, and if this happens on a low reader dyno, then the power matches the boost level and setup, although you could make some more power on that boost level. Mapping has all to do with how much power you make. From the power levels you posted here in relation to boost and setup, I conclude that the fuel that you use is up to the job, and since your tuner wants to make more power by increasing boost, and there is no problem knockwise, that means that the fuel has a good calorific value and can take even further compression with added boost.







Marios

boostedup

Hi there note that it's to boost we got out of it was by putting a bolt in the wastegate can completely rocking it off it's not opening at all you can put a piece of paper in front of a screamer pipe and it doesn't move. moving the cam timing around changes the exhaust manifold pressure and the power level but doesn't affect the boost.
Wewe are going to check on an old gt42 that the tuna has around the workshop and see what happens, that's not a 5 second job though as it is a different manifold housing and doesn't line up with the intercooler like the turbo that's on there now

4G63Rules

iTrader: (10)

Has a leak down test been done? It seems a lot of things have been checked, but you might want to think about having them perform a leak down test to see if the motor is in perfect health. It could be leaking passed the valvetrain.

boostedup

The engine is brand new, not breathing heavy either, extremely unlikely to be the issue

Evo8cy

Changing the cam dial combo, changes the dynamic compression of an engine and thus it affects the way the boost behaves, especially the wgdc. Using the optimum dialing combo in other words increases the V.E of a setup and thus one will need to use more wgdc on the same lbs/in spring to achieve the desired boost level. The reason you see higher exhaust gas velocity and pressure is due to the exhaust gas higher cfm which in turn is due to the increase V.E which happens as I said when you change the dynamic compression of an engine. Also the optimum cam dialing allows you to add more timing to the map. There cannot be added exhaust gas pressure and velocity without added exhaust cfm, and in order to have more exhaust gas cfm means the engine draws in more air. I do not believe your brand new turbosmart wastegate was leaking in the first place and the screw in it was not needed, neither does a single 27psi 45mm wastegate need more than 60%( even with light backpressure issues ,as you say you have none) of duty cycle to be able to hold 43psi of boost. If the wgdc was at 100% and the problem was the leaking wastegate, with the screw in and 100% duty cycle you should be able to hold 53+ psi at least of boost, not just 3psi more. The reason you achieved the extra 3 psi is the cam dialing due to the increased V.E and the alteration of the maps which slightly raised the flow of the turbo. The super 99 on a well prepared setup is at its optimum efficiency range , flow wise between 45-55psi. It can definitely flow above that, but as the pressure ratio goes up, flow goes down.



Eliminate both gates, bov and external, block off everything, and run the setup without any boost control system.

Post up screeshots of fuel and timing maps.







Marios