Jump to content
SAU Community

Recommended Posts

hey guys !!!!

got a hi-flowed turbo and all supporting mods on my r33 s-II (coil packs, fmic,z32 afm, pod etc.).

the turbo can't flow enough air at high rpm so it drops from 18psi to 15psi and making only 301rwhp.

any ideas/ suggestions on what my options are to get to 350hp mark ?????

Will I have to get a new turbo altogether or are there any other options???

If new bigger turbo is the only answer, what turbo? are there any bolt on solutions?

here's the dyno graph ..

post-58092-1229821581_thumb.jpg

Cheers !!

Link to comment
https://www.sau.com.au/forums/topic/249701-im-after-350rwhp/
Share on other sites

How big is the front, if the front is big enough maybe its just the rear housing that is not flowing enough, in that case the simple option is a vg30 rear housing which is .8 not .6 like and rb25 turbo, i have a high flow with one, only have fmic, k&n panel filter, 3" exhaust, hi flow cat and one piece split dump and it makes 299 rwhp, once i put in bigger injectors, z32, fule pump and management i will be maxing it out at around 350 rwhp.

My dyno graph is much the same as yours but i am making the same power as you at the same rpm but with less boost, my 299hp was at 6000rpm @ 14psi.

post-27276-1229835901_thumb.jpg

what wastegate actuator are you using? if you have a rb25 one then they are weak as piss and can cause this.

get a upgraded wastegate actuator with a 15psi spring and then re-tune it to 20psi and you should get close to the power your after

How big is the front, if the front is big enough maybe its just the rear housing that is not flowing enough, in that case the simple option is a vg30 rear housing which is .8 not .6 like and rb25 turbo, i have a high flow with one, only have fmic, k&n panel filter, 3" exhaust, hi flow cat and one piece split dump and it makes 299 rwhp, once i put in bigger injectors, z32, fule pump and management i will be maxing it out at around 350 rwhp.

My dyno graph is much the same as yours but i am making the same power as you at the same rpm but with less boost, my 299hp was at 6000rpm @ 14psi.

post-27276-1229835901_thumb.jpg

what wastegate actuator are you using? if you have a rb25 one then they are weak as piss and can cause this.

get a upgraded wastegate actuator with a 15psi spring and then re-tune it to 20psi and you should get close to the power your after

Thanks for the replies guys, I'll check with the guy who hi-flod the turbo, what housing .6 or .8 and what wastegate actuator were used. At this stageall I know is the wastegate is internal...

checked with the workshop and it was the stock rb25 wastegate actuator used (3 psi or something). will change this to a better one in Jan... he said this will be a 13.8psi... will this do the trick??? I guess only one way to find out !!!

  • 3 weeks later...
checked with the workshop and it was the stock rb25 wastegate actuator used (3 psi or something). will change this to a better one in Jan... he said this will be a 13.8psi... will this do the trick??? I guess only one way to find out !!!

Just wondering if setting the higher boost duty circle will help holding the boost?? :D

checked with the workshop and it was the stock rb25 wastegate actuator used (3 psi or something). will change this to a better one in Jan... he said this will be a 13.8psi... will this do the trick??? I guess only one way to find out !!!

Can anyone confirm the size of the stock wastegate actuator? I thought it was 7psi?? Cause i think they did the same with my gt3076r upgrade. Its a lag fest. I got a 18psi spring going on next tuesday.

In your case there is no way you will make 350rwhp with a high flow. I bet Andrew told you that you wouldnt see those figures too. Thats why i went the gt3076r and not a highflow.

However i reckon you might get 325rwhp at most on his dyno with a 1 bar actuator. The boost will come on heaps early and should hold all the way.

um, rb25 actuators are 7psi, rb20 actuators are 10psi, HKS actuators are adjustable but from memory the minimum is 14psi? correct me if im wrong,

thats why people say using the rb20 actuator on the 25 turbo ends up working better,

HKS actuators cost mmm well with our crap exchange rate now probably $200, was $130 delivered when i checked last before the crap dollar

Can anyone confirm the size of the stock wastegate actuator? I thought it was 7psi?? Cause i think they did the same with my gt3076r upgrade. Its a lag fest. I got a 18psi spring going on next tuesday.

In your case there is no way you will make 350rwhp with a high flow. I bet Andrew told you that you wouldnt see those figures too. Thats why i went the gt3076r and not a highflow.

However i reckon you might get 325rwhp at most on his dyno with a 1 bar actuator. The boost will come on heaps early and should hold all the way.

I kinda realised that I'm not gonna get 350hp with this turbo, but if I can run 17-18psi and hold through out the rev range I'll be more than happy (with what ever the rwhp number I get)

I don't wanna pay for whole new turbo setup just for few hp

Is it straight forward to change the actuator to a 1 bar actuator? which brand is recomended??? are there 18 psi actuators out there?

and yeah !!! Andrew told me that 350 is not gonna happen with this turbo. :D

Just get the HKS actuator. My stock actuator got busted, stuck at 0.4bar all the time. Got the adjustable and wind it up til 0.73bar which was max for the stock turbo (using stock ecu). Winding it up anymore would cause like hitting a wall kinda feeling. lol

BTW the HKS acutator can go over 1 bar easily.

post-48477-1232715076_thumb.jpg

Edited by teng
I kinda realised that I'm not gonna get 350hp with this turbo, but if I can run 17-18psi and hold through out the rev range I'll be more than happy (with what ever the rwhp number I get)

I don't wanna pay for whole new turbo setup just for few hp

Is it straight forward to change the actuator to a 1 bar actuator? which brand is recomended??? are there 18 psi actuators out there?

and yeah !!! Andrew told me that 350 is not gonna happen with this turbo. :P

Well if you hadnt noticed your thread says im after 350rwhp. Your asking the wrong questions.

Get a suitable turbo first!

Do people know how much you can get out of a high flowed r33 turbo? Mines a RB25 and im making 290Hp at 12psi. But they guy that tunes it said he wound the boost up too 20psi but only got about 10 more Hp. Does this sound right?

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

    • GCG is a good company, they're a major distributor for Garrett in Japan as well.
    • Nah, OEM washer bottle and brake fluid reservoirs are fine I don't know what it is with the plastic that Mazda used, some plastics, like the washer bottle and brake fluid res are fine, and still look new after 20 years use, where as the coolant expansion tank, and PS reservoir, that I replaced with new OEM items when I first got the car, turned yellow and started getting brittle a few years later If the dirty yellow stained plastics didn't trigger me there wouldn't be an issue, but they did, much like the battery bracket....... Meh As for going back to work full time to support car stuff, nope, why, because I own a Mazda NC MX5, not a Nissan R series Skyline 🤣
    • I've never heard of CJ-motor, so can't advise you on them. I'd just go straight to GCG for a GCG highflow though. Seems no point to use a middleman. I'm somewhat surprised that the price on the CJ site is lower than the GCG retail price. Even though CJ would get a discount of some sort, you would hardly expect them to give up so much margin. Maybe the price is out of date? Having said that "I'd go to GCG"...when I did my highflow, I went to Hypergear. I did this https://hypergearturbos.com/product/rb25dethighflow/#tab-dyno-results with the R34 OP6 450HP profile. With the BB centre (extra $400) and intially with the standard boost actuator, but I eventually got him to send me the high pressure one when I got to the point of being able to actually use it. Ends up costing the same sort of money as the GCG highflow, but this is, of course, the turbo that I KNOW has a shorter length core and so moves the comp cover rearwards. The GCG apparently doesn't do that. My mechanic also swears by the GCG highflow, given that we have another turbo rebuilder who does something essentialy the same as theirs, using Garrett wheels. He says it stands up at really low revs and makes good power. I haven't pushed my HG highflow past ~240-250rwkW yet (should have a little more in it, but unclear how much) and it does have a fairly gentle boost ramp. OK, it's much better now that I have gotten my boost controller tuned up on it.  A lot of my earlier unhappiness was because I couldn't keep the wastegate flap as closed as it needed to be (including some mechanical issues). I'd still prefer it to boost up nearly as quickly as the stocker, and it certainly a bit slower than that. So maybe the GCG one is worth the first look (for you).
    • Ok thanks 🙂 I will higly consider this. Any "known" company for a good reviews and experience to send that off? Is that CJ-motor good one? Or go straight to GCG site? I need to use VPN to even find some of those "shops" let alone access them 🙂 
    • You can literally put in as much WMI as it takes to quench the combustion totally (and then back it off a little, obviously), and it will keep making more and more power. The power comes from the cooling effect of the water (and the meth) and the extra fuel (the meth, which also has massive octane). It is effectively exactly like running E85. One might be slightly better than the other, but they are damn close. But with either you can lean on the boost or the timing (or both) waaaay more than with just petrol and the results are similar. Here's the first thing I googled for an anecdotal bit of evidence. Can't access the attachment without being a gold member, but it is there for the getting if able to, or searched up elsewise perhaps. https://www.hpacademy.com/forum/general-tuning-discussion/show/wmi-vs-e85/
×
×
  • Create New...