Ryno

Good to hear you resolved the issue mate. Since my last posts, I have been continuing to improve the tune but haven’t had it on a dyno. I’ve swapped the front hubs to GK Tech ones, in hindsight it’s a change that has pro’s and cons (in a street car). The improved front roll center has definitely increased the grip at the front of the car, so much so that I’ve stiffened the front sway bar fully and removed the rear sway bar to fix the balance and stop mid corner oversteer. The drawback is the tyres scrubbing at high lock angles due to the change in Ackerman, this is particularly frustrating when parking the car at low speeds.

It’s very normal. It was a straight swap from my previous head unit.

It just fits, the top right corner just touch’s. However I like that it does as it further prevents any vibration from the display.

My exhaust is similar (I also have a Venom Cat) but I only have a 3” dump. I doubt the exhaust is the issue, as if the wastegate is doing it’s job it should always be the path of less resistance, rather than going through the turbine. It’ll be loud, but I’d be tempted to give it a run with the wastegate removed to see what boost is produced. Just limit it to one pull to make sure the hot exhaust gases don’t damage the engine bay. Then you’ll know for sure whether it is the wastegate or something else.

I haven’t hit the dyno with it yet. I tuned it myself with the Power FC hand controller as I have a wide band sensor permanently wired in. I should get it on there, just haven’t found the time. I’ve made a few more changes to the car over the last few years... Some suspension arms upgrades, rear cradle mods and GKTECH front hubs. I ditched the standard Radiator clutch fan to an electric fan (this improved my fuel economy by around 0.5 to 1 liter per 100kms). i upgraded the alternator (again!)... this time to an new LS1 140 Amp unit. I also swapped out the head unit (for the 4th time since I’ve had the car) to a Alpine HALO 9 head unit (which I can’t recommend highly enough!). Externally the car looks the same.

Yeah unfortunately my HKS GT-RS expired last year after I got some head work done. I think the extra flow was too much for the old girl. At the time the best value option For replacement was a Arashi GTX3071R. It goes well, but is definitely not quite as responsive as the old GT-RS.

I’m fine with the discussion mate, hope you can workout what’s going on.

Yeah my manifold is the same and I certainly haven’t experienced the same issues you have described. I changed turbos last year to a GTX3071R (from the HKS GT-RS) but didn’t change the manifold or wastegate setup, and have had no boost control issues with either turbo.

I have purchase a replacement head but I’m still keen to get four replacement intel valves if anyone has some available

I’m chasing four stock RB25DET inlet valves or a complete S2 RB25DET Head if it’s at the right price. PM me if you have what I’m after, cheers

Are you trying to squeeze that into the R32 headlight body? If so, I'm bloody impressed and will look awesome if you can make it work.

Yeah the idle and light cruise wasn't too far off, the on boost part of the map required the largest change

I had the same issue when I swapped out a Walbro pump for a Nismo. Even though both pumps are quoted as a similar flow rate, the Walbro flowed significantly less - I had to take around 10% of fuel out of the tune to correct the Air/Fuel ratio change.

The manufacturer of my plenum now operates under the name "Sydney Motorsports Engineering", the best way to check them out is on Facebook. I had a quick look and there's a post on 12 Feb 2015 which shows the plenum, or you can check out my build thread (for more pictures) in the projects section on here.

I used to have that style of manifold, but after several years swapped back to the standard lower runners with a MX Performance/SME plenum top (similar to plazmaman). The shorter runners really kill the torque and also increase the spooling time of the turbo - unless it's a dedicated race car there's no way I'd consider a short runner manifold (like the Otaku Garage one) again.