Jump to content
SAU Community

Recommended Posts

Im in the process of getting my R34 GTT highflowed ( GCG). Since the exhaust housing is larger then the R33, I should be able to gain 30 odd extra rwkw . I have a 38mm tial wastegate laying around which i was going to use on a different setup but changed my mind. Im thinking of welding the internal shut and change to the external instead. Im assuming that this will allow for better boost control and maybe even push the turbo to around 280-290 rwkw. Could i still use the standard exhaust manifold and get it modifyied with the wastegate or get a custom one fabricated up? What cost are involed?

Link to comment
https://www.sau.com.au/forums/topic/128870-r34-gtt-gcg-high-flow/
Share on other sites

An external wastegate does not increase turbo power.

A wastegate int or ext is there to regulate boost pressure. One does not make more power than the other in a correctly working situation.

If the turbo suffers from a int gate hole that is too small, boost control problems can arise.

Seeing as though no-one to date has reported issues, there is no need.

You can convert it to external if you want, people do weird things all the time.

However, you are mistaken if you think it will make anymore power.

Its that simple. How better boost control equals more power i dont understand. 20psi is 20psi. Doesnt matter what regulates it.

IMO, why butcher what is proven to be a superb turbo?

Ext gate with a screamer pipe will make more hp... however otherwise there is no point in it. A good new elc boost controller will be able to regulate ur boost settings fine, if you cant a actuator with a stronger spring then the elc boost controller onto that will do the job. I found abit more lag with the external gate so i wouldn't go down that route unless you REALLY love the noise and want around 10-15 more rwhp at most

and nothing else was changed?

was this peak power? average power? power lower in the rev range???

just when you think of what a wastegate does.... it controls boost

so unless it wasn't doing its job in the first place and the boost was dropping, there is nothing to explain the increase

To be honest... external gate brought power on later (around 300-500rpm) but controlled it MUCH better. I have 20psi from about 4500rpm to 8000rpm.

The increase was from having no restrictions in the exhaust, it went from a split 3' dump/front to a single 3' dump/front and the screamer comes off the ext wastegate, there is no mixing of the exhaust cause turbulance which is wat makes the exhaust wheel spin easier! Or so logic should go... lol

Edited by jazza08
I made 12rwhp from it...

If only i kept the old fkn dyno sheet damn it!! I was so proud of my new one i didnt keep the rest lol

12rwhp would suggest to me dynoing difference rather than an actual power increase.

Being you can go to the same dyno, a week apart, and the reading wont neccesarily be the same.

To be honest... external gate brought power on later (around 300-500rpm) but controlled it MUCH better. I have 20psi from about 4500rpm to 8000rpm.

The increase was from having no restrictions in the exhaust, it went from a split 3' dump/front to a single 3' dump/front and the screamer comes off the ext wastegate, there is no mixing of the exhaust cause turbulance which is wat makes the exhaust wheel spin easier! Or so logic should go... lol

Damn posting while im typing.

If you had a restrictive exhaust, then thats where the gain came from.

It has absolutely nothing to do with the wastegate itself.

I bet you if you changed to a 3.5-4" exhaust keeping the internally gated turbo... you would see the same increase in power... all beit a poofteenth in your case.

As for boost coming on later, thats poor wastegate spring selection. im guessing, so your getting a bit of gate creep as it cant keep the thing shut long enough

oh well

back to the original issue ..

280-290 kw - sell the tial gate, spend a little extra on poncams.. and have a more streetable car that would have close to your power targets.. be very hard to defect and less fabrication costs ..

fabrication costs and first defect would pay for the rest of the cams anyway

see abo bob's r34 GTT 4 door Auto for comparison ..

Damn posting while im typing.

If you had a restrictive exhaust, then thats where the gain came from.

It has absolutely nothing to do with the wastegate itself.

I bet you if you changed to a 3.5-4" exhaust keeping the internally gated turbo... you would see the same increase in power... all beit a poofteenth in your case.

As for boost coming on later, thats poor wastegate spring selection. im guessing, so your getting a bit of gate creep as it cant keep the thing shut long enough

Thinkin about that.. it may not be true because i never ran 20psi when it was internally gated... full boost was more around 15psi and made that abit earlier as you'd expect. Ah well im happy with the result for now, on the issue id also say cams are a better option than spendin money on gate etc if hp/driveability is ur main goal

Each post you make you give more information... :sorcerer:

Next time put it all into one post next time, makes it easier to make a comment on it all rather than posting little snippets each time you reply until we get the full story a half a dozen posts later :rofl:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Yeah i found that alot of parts can be wrong or "very" hard to get the real right one. I already bought some brakes years ago on me "old" GT calipers and they were wrong too 😄  I told them too. Even send them pictures...but they said "EBC catalogue has them on my car... So i dont know what their answer will be. I call monday them and let them know that they are really not on my car. If they were they would be already on a car...
    • Welcome to Skyline ownership. Yes, it is entirely possible parts websites get things wrong. There's a whole world of inaccuracies out there when it comes to R34 stuff (and probably 33 and 32). Lots of things that are 'just bolt on, entirely interchangable' aren't. Even between S1 and S2 R34's. Yes they have a GTT item supposedly being 296mm. This is incorrect. I would call whoever you got them from and return them and let them know the GTT actually uses 310mm rotors. Depending on where you got them from your experience and success will obviously vary.
    • Hi...a bit a "development" on the brakes. I spoke to the guys where i get brakes from...and they are saying that 296mm EBC are for R34 GT-T. I then went to their site: https://www.ebcbrakes.com/vehicle/uk-row/NISSAN/Skyline (R34)/ and search for my car(R34 GT 1998 - it has GTT brakes) and it show me this USR1229 number and they are rly 296mm rotors... So now iam rly confused... The rotors i have now on the car are 310mm asi shown... So where is the problem? Does the whole EBC got it wrong or my calipers are just...idk know what?  
    • Oh What the hell, I used to get a "are you sure you want to reply, this thread is XX months old" message. Maybe a software update remove that. My bad.
    • This is a recipe for disaster* Note: Disaster is relative. The thing that often gets lost in threads like this is what is considered acceptable poke and compromise between what one person considers 'good' looks and what someone else does. The quoted specs would sit absurdly outside the guards with the spacers mentioned and need  REALLY thin tyres and a LOT of camber AND rolling the guards to fit. Some people love this. Some people consider this a ruined car. One thing is for certain though, rolling the guards is pretty much mandatory for any 'good' fitment (of either variety). It is often the difference between any fitment remotely close to the guards. "Not to mention the rears were like a mm from hitting the coilovers." I have a question though - This spec is VERY close to what I was planning to buy relative to the inboard suspension - I have an offset measuring tool on the way to confirm it. When you say "like a mm" do you mean literally 1mm? Or 2mm? Cause that's enough clearance for me in the rear :p I actually found the more limiting factor ISNT the coilover but the actual suspension arms. Did you take a look at how close those were?
×
×
  • Create New...