Harey

Funny how you guys look for any chance to get at Tao even if it doesnt make any sense (above) but dont comment on him possibly solving the issue the OP is having, low compression and incorrect turbo selection.

You think its a boost pressure limit and not a power limit? Its probably a combination but I dont think you would get valve float at such low power. Tao's car cops constant abuse at mostly over 300rwkw, surely the high power has a major factor as well.

Aha, that could be it Tao! It makes a lot of sense. With a lower comp engine you need more boost and a larger turbo to make some good numbers.

I just know if it was me spending 4k on one then I would be demanding the Pro S until I see a lot of good results on an RB25 from the KAI.

If you liked the HKS GTRS on the RB25 then you are a response man, its good to work this out before you start purchasing. People can have very different opinions on the same turbo. Get some -7 or -9 turbos and you will have very close to the same response you do now, but with more mid and top end. Then add E85 as said above to make even more power!

Depends what your getting charged with and how guilty you are

GCG Also sell a complete kit with the lines, dump pipe etc. I believe the price was around $3k for the GT3071/76 so I wonder if its gone up for the GTX series?

The thing that concerns me is the HKS GTRS has only a slightly less power rating and yet in real world terms the 2835 Pro S is well ahead in terms of peak power.

Count me in

what are you chicken...

how about smallest turbo that is running efficiently for the power application = win?

This rings alarm bells for me as you know how much this can affect the Garrett equivalents when they bolt straight up to the standard dump pipe. If you are going to spend the money on a HKS, then I would be demanding the Pro S. How many successful results do you need. Also its not hard to buy a 3" front pipe and simply boly up the HKS dump to it, then sell your 1 piece.

What R31Nismoid is trying to tell you is have a look at the RB25 dyno thread there are 30+ pages of peoples results! Not to mention just running a search in this section. You are going to get much better results doing this than simply sitting here and waiting for everyone to hand you every bit of info.

Interesting, I could understand that it did not improve the boost control as the wastegate was overcoming the actuator spring but I cant understand how it could make the boost control worse?? I dont think it was setup correctly.

I think shocking is a slight exaggeration. Yes it could be improved but take a look at joeyjoeys boost curve with the same turbo, it hits boost faster but still drops off about 2psi. It could be the turbo and engine combination that means it cant hold 20psi till redline. Turbos that have a strong midrange can often do this. A lot of the 3076s and hypergear turbos seem to exhibit this behaviour. I think someone said its to do with the amount of air flowing through the wastegate pushing the wastegate open (overcoming the actuator spring). In this case I dont think a boost controller can help you. But by all means I would be winding the gain up to get it as close to joeyjoeys result as possible.

Yeah after some quick googling, looks like the early 2000 model ones the C5 and has a V8TT and newer 2008 onwards C6 has a V10TT.

Its the same format as joeyjoeys dyno so 'Dyno Dynamics'

$300 isnt too bad, depends how long they spent I suppose. Excellent response/midrange there, 130rwkw at 3,500rpm, 195rwkw at 4,000rpm. Yup strange dip from 4800-5400, but then a nice top end especially considering the boost is dropping. Joeyjoeys drops about 2psi but yours is about 4. So not too bad but I agree the gain should be wound up a bit more to improve it. Still great result and I would prob leave it as is until you come back with E85

My understanding is the op is running a 0.68 exhaust housing. joeyjoey runs the 0.68 rear and makes 280kw on 98 and 320kw on E85. I would definitely recommend the 0.68 for a good combination between response, mid range and peak power. I think the 0.68 is the default option in the rb25 kit anyway.

The link to the 400rwkw thread is not really applicable, they are all built motors.

Thats strange I thought the Pro S had either a 0.68 or 0.87 exhaust housing??

Guys the 2835 Pro S kit for the RB25 definitely comes with the 0.68 exhaust housing by default: http://cgi.ebay.com.au/HKS-Turbo-Kit-GT283...=item20b4f48ef8 The 0.68 is how they get the awesome response and mid range, but it still seems to be big enough to flow 280-290rwkw on 98, which is enough for most people on stock rb25s. If someone can repair turbos this could be a great buy: http://cgi.ebay.com.au/R33-R34-RB20-RB25-G...=item19c1223b3b

Lots of info here: http://www.skylinesaustralia.com/forums/Ti...amp;hl=tirerack

Thats fantastic news mate! Well done. Awesome peak power figure and knowing the turbo it will have a very strong mid range. Just concretes my opinion that these are the best turbo for a stockish RB25 engine.

General consensus is to keep checking the fuel filter when you first change to run E85, and change it if its dirty of course. Or buy a washable fuel filter like NYTSKY.