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Hi everyone,

Took my car in for a full re-tune on Friday 01/09/06 after installing a new batch of goodies... spent all day at it once again (literally) and came out a very happy man; yet not so happy (you know what I mean).

Tuner spent most of the day mapping the fuel maps and the ignition maps making sure they're all perfect and smooth - I kid you not; they're SMOOTH!!!

Came out of the room with 225.31rwkw @ 10psi - we had hit a boost "leak" problem.

EDIT: Dyno Graph Uploaded 060906

bd4s0109060001rc5.th.jpg

PROBLEM: With the EBC (cheapy hybrid one) set at 18psi; it built up boost quickly (1bar by 3,500rpm and full by 4,500rpm) but at 5,500rpm onwards it dropped/leaked back down to 10psi. This resulted in my lower than expected max power figure. Had the boost held 18psi all the way to 7,200rpm redline; we're certain we'd be up around the 250-265 area.

Anyways; what I'm wondering is what the cause of this is... there are a few theories:

1) The Boost Controller

2) The Wastegate Actuator (still stock)

Want to get the right answer so when I get sick of this 225rwkw feeling; I'll fix it up and get it tuned once more. Just want to know what the cause is so I can get the right parts to fix it up. At the moment the car is awesome; very smooth!

Big round of applause to the guys at BD4s for spending all day on it and getting it perfect to what it's capable of. Many thanks to Mitch and Trent from NBP for also taking the time to be there and work on the car when solving the problems.

Will post up a dyno graph tomorrow; left it at home~

Stan

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I recomend doing both. For wastegate actuator HKS one can be beaten, cheap and adjustable :)

boost controller I can't fault the greddy profec B. Cheap and good. I'll post up my latest graph tonight and you can see the boost curve. it boost up hard to 14.5 psi by 3500 rpm and holds perfectly flat to redline.

good work on the 225kw though, it must feel pretty quick now.

Well done, will be interesting to see the result after you get the boost issue sorted. Perhaps you could try to get a actuator a bit closer to your desired boost setting stock is only 5psi, RB20DET one is 10psi, and HKS make an adjutable one 12psi to 1 bar I think but dont quote me on that.

cheers

Yeah thanks; already looking into a HKS one Beer Baron :) and you are correct; feels damn quick in the mid range as it's got 18psi pushing it along - just wish it held boost :)

Munna1; thanks for that information - didn't know that :)

Would be keen to find if its the controller (I too use the Hybrid - holds boost perfect;y up to 12psi so far, lol!), however my money is on your actuator. Id be looking into the HKS adj. actuator from Nengun.

Yeah; bets are being placed on those 2 items; there's nothing else that could be wrong.

We did find that there was a small leak at the air temp sensor used by the F-CON but that equated to 0.01bar at 7,200rpm so we weren't too concerned (still this will be welded up and sealed)

If anyone has any different suggestions/opinions please feel free to shout out!

Stan,

What AFM are you running? you aren't running the stock RB25 AFM still are you? Because i didn't notice a Z32/Q45 AFm on your modlist.

Doesn't the stock RB25 AFM max out around 220-230rwkw mark?

anyways worth a try.

the r34 afm has a bit higher resolution (not sure how).

have seen a few 240rwkw-250rwkw on stock afm still.

and even when it does max, it still works it just runs map sensor style and you get a few less load points

Actually this is a bit easier:

http://satan.p5.org.uk/modification.html

Everything on that list is in there... except the HKS Actuator which I didn't get enough time to order/install.

have you tried borrowing a boost controler like that Ebay one, I know you might say WHAT!!!! but I find they hold boost really well worth a try to see if it stops the spike, otherwise for something this extreeme I would be looking at a external wastegate they are heaps better then internal and can give you better control over boost

be very careful and run unlimited boost on the dyno and see how it alters the results. obviously back off when u see it peak past 1.3 bar or see it lean out.

that will indicate if its the controller and actuator playing funny buggers

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