400Hp Rb26 - Where To From Here?

[djr81]

Where to now?

I have an RB26 in good condition (not long been built), but at only 410rwhp it doesn’t exactly light things up.

Has the following:

Forged internals.

-5 turbros, HKS actuators.

Cast iron exhaust manifold, ported.

Tomei dumps.

Apexi exhaust.

256 degree inlet cam.

252 degree exhaust.

Cam gears.

75mm I/C with a hard pipe kit. Stock inlet manifold.

Power FC off Z32 AFM’s.

Blitz ID III boost controller.

Other stuff than means it wont go bang but that dont relate to output.

It came back from the tuner with 410 horsepower and a note that they could only get the boost controller to run to 16lb. It apparently made 22 with the wastegates shut but no idea what horsepower.

Questions are twofold:
On the assumption (perhaps misguided) that it’s the problem where do I go looking to properly diagnose the boost control fault as the shop couldn’t find it (They blamed the wastegate actuators).

Once the thing has been wound out to whatever boost it is capable of running I assume it would only be good for short of 500rwhp. So, the question is where do I go looking for more horsepower. The following options come to mind.

1. Replace the twin turbo pipe with something aftermarket which may help a little.
2. Go to a larger inlet cam (Poncam A?)
3. Adjust cam gears for days on end.
4. Dunno.

Please note E85 is not a viable option where i am.

[wedge_r34gtr]

Actuators not adjusted correctly????

[djr81]

Were brand new in box. Now brand new in car.

[Chris32R]

Who did the tune for you?

[GTSBoy]

#1 suspect in these threads lately is exhaust restriction (ie funked up cat converter or dodgy Jasma muffler narrow point). Second is usually rag in the intercooler piping for shits'n'giggles.

[djr81]

Who did the tune for you?

Went with your recommendation of Sean. Happy with the tune, just want the rest of the horsepowers.

[YoLoBaCh]

bash out the cat

[Piggaz]

Twin turbo pipe is fine. Maybe put the divider in it but it won't be the cause of the low figure.

Cams won't help here. Stock cams will go much further than that. Something is Definately amiss.

[djr81]

Twin turbo pipe is fine. Maybe put the divider in it but it won't be the cause of the low figure.

Cams won't help here. Stock cams will go much further than that. Something is Definately amiss.

Is there an approximate number that -5's can be made to run to - hp & psi?

Be happy if the cams are not suspect. Once had Poncams B's. They sucked teh balls off a mange ridden dog.

Thing is the power curve is about right when compared to an old, stock motor with much the same specs for bolt on stuff (dyno comparison dodginess aside). Within a few horsepower right along the range.

[Piggaz]

Is there an approximate number that -5's can be made to run to - hp & psi?

Be happy if the cams are not suspect. Once had Poncams B's. They sucked teh balls off a mange ridden dog.

Thing is the power curve is about right when compared to an old, stock motor with much the same specs for bolt on stuff (dyno comparison dodginess aside). Within a few horsepower right along the range.

Depends on setup and supporting parts so impossible to say.

Funny that you say that about type B's .

305 kw at 16 psi isn't toooooo bad on -5's with such a basic setup. Needs more boost. Chuck 22-24 psi at it and see what happens.

[XKLABA]

Find out why you can not dial in boost, sort that then dial boost up to 22-24 psi, that should see you a lot close to the 500rwhp mark

What boost controller have you got, did you check the actuators where set correctly and identically

[djr81]

Find out why you can not dial in boost, sort that then dial boost up to 22-24 psi, that should see you a lot close to the 500rwhp mark

What boost controller have you got, did you check the actuators where set correctly and identically

Dunno why boost cannot be dialed in. To the best of my understanding it was that the wastegates cannot be kept shut due to insufficient flow through the boost controller.

Controller is a blitz dual solenoid type.

What does set correctly look like on the actuators?

[XGTRX]

Not the first time these bcs have caused issues. Buy a turbosmart manual bc and bypass the blitz one all together. This is a good starting point. Just make sure the actuators have been preloaded though..these two thing fix 90% of this type of issue.

[zebra]

excuse me while I wet myself laughing at the idea of removing one of the better jap boost controllers to replace it with the worst boost controller in the history of boost controllers

[Piggaz]

Manual? FFS.

The plumbing could possibly be wrong. Actuators might not be setup correctly.

Check setup.

[KiwiRS4T]

If /when you fix your boost control problem you say what's next after 500hp.

Really depends how much power you really want/are prepared to pay for.

Since you have already forged (and presumably balanced) the bottom end you won't be wanting an RB30 so you could have a look at bigger/ more modern single turbos .

I don't know if the PFC would hold you back in any way but you could consider a Link/Vipec

Have you done much about your brakes and suspension?

[Ben C34]

Not the first time these bcs have caused issues. Buy a turbosmart manual bc and bypass the blitz one all together. This is a good starting point. Just make sure the actuators have been preloaded though..these two thing fix 90% of this type of issue.

Wow.

[XGTRX]

Not saying they are better just saying if the ebc isn't setup right then a manual one is simpler to setup...just for fault finding that's all. This process has work many times in the past. Or don't do it this way and fix it another way...doesn't worry me.

[XKLABA]

It is most likely hoses on the wrong way after rebuild, go back and recheck your work

Has it worked at all in its current state, if so it could be a faulty solenoid, if not then check the hoses are right

To check actuators you have to apply air pressure at different levels and measure how far the arm has moved on both to make sure they have moved the same difference, manual bleed valve will not fix this, this will most likely not limit you to 16psi either

You will also need to check preload on the actuators, done the same way as above, but this time record the movement vs pressure appied, IIRC they should start to open about 2psi under what they should set at and be fully open about 7psi over, this is because they don't have the manifold pressure pushing the gate open internally, I could be a bit off with these as I haven't done it in a long time, and this is most likely the problem

Not enough air flow would result in over boosting as it doesn't have enough air to open the gates and shut gates means no bypass which gives to much boost

What happens if you turn off the boost controller

[djr81]

Not saying they are better just saying if the ebc isn't setup right then a manual one is simpler to setup...just for fault finding that's all. This process has work many times in the past. Or don't do it this way and fix it another way...doesn't worry me.

It will run to 22 psi or similar (without any finessing) but I want a decent controller.

If /when you fix your boost control problem you say what's next after 500hp.

Really depends how much power you really want/are prepared to pay for.

Since you have already forged (and presumably balanced) the bottom end you won't be wanting an RB30 so you could have a look at bigger/ more modern single turbos .

I don't know if the PFC would hold you back in any way but you could consider a Link/Vipec

Have you done much about your brakes and suspension?

On the assumption it will go to 500 I would be looking for small gains, say 30hp at most. Would not bother if it was too hard/expensive. the last thing I need is something with a Hollywood number and no midrange.

Brakes and suspension. Are they important? It is only 500hp after all.

But seriously it has had a huge amount of effort put into the handling and the brakes upgraded.

Manual? FFS.

The plumbing could possibly be wrong. Actuators might not be setup correctly.

Check setup.

Yeah will do. Hoping someone may have had a similar experience and be able to finger, say the solenoids as a common failure mechanism for example.