Jump to content
SAU Community

Recommended Posts

With a Electronic Boost control can you alter boost pressure at different rpms. Im getting 17psi at 4500rpm and then it drops off too 12psi and peak revs. This is using a HKS actuator and no bleed valve so its not the actuator spring. So i thought with a EBC could i dial in more boost pressure at say 6000rpm.

Can i do this?

  • Replies 46
  • Created
  • Last Reply

Top Posters In This Topic

Some EBC's are not intelligent.

Some operate in a closed loop mode that monitors boost and adjusts the duty cycle to suit. The cheaper EBC's tend to have a fixed duty cycle which is why you get boost dropping at higher rpm's.

I used to own a Blitz SBC-ID EBC that had a manual function and auto function.

The manual function was like the regular ebc where you set it to a duty cycle.. Say 43. then you set the gain which controls how fast boost reaches that duty cycle peak if that makes sense. It would make 15psi then tapper off to 12.5psi by 7000rpm.

Then there was the auto function that would require you to dial in the boost you want (say 15psi) it would then slowly learn the boost curve and adjust the duty cycle to suit. This would require multiple 7000rpm runs.

Once learnt it knows that it has to reduce the duty cycle in order to hold that 15psi a certian RPM. It would then hold 15psi to redline.

Wait until you get the PowerFC & get the boost controller to suit that. :mad:

The PowerFC boost controller is essentially the same as the AVCR which is a very good boost controller. Some do not like the AVCR due to its complexity and thoughts that a bigger solanoid is better. Which is untrue. :mad:

EDIT: Stock turbo or not.. It has nothing to do with it. A good EBC will hold boost. i.e the rb20t turbo was able to push 16psi at 7000rpm on the rb20det when with a crappy bleeder it would tapper off to 12.5psi. You need an intelligent EBC. AVCR, Blitz SBC-id or the Greedy E0-1 (Expensive) I think it is.

How good of a boost controller do you consider something like a GReddy Profec B-Spec II, or even a Spec-S?

Some EBC's are not intelligent.

 

Some operate in a closed loop mode that monitors boost and adjusts the duty cycle to suit. The cheaper EBC's tend to have a fixed duty cycle which is why you get boost dropping at higher rpm's.

 

 I used to own a Blitz SBC-ID EBC that had a manual function and auto function.

The manual function was like the regular ebc where you set it to a duty cycle.. Say 43. then you set the gain which controls how fast boost reaches that duty cycle peak if that makes sense. It would make 15psi then tapper off to 12.5psi by 7000rpm.

 

Then there was the auto function that would require you to dial in the boost you want (say 15psi) it would then slowly learn the boost curve and adjust the duty cycle to suit. This would require multiple 7000rpm runs.

Once learnt it knows that it has to reduce the duty cycle in order to hold that 15psi a certian RPM. It would then hold 15psi to redline.

 

 Wait until you get the PowerFC & get the boost controller to suit that. :cheers:

The PowerFC boost controller is essentially the same as the AVCR which is a very good boost controller. Some do not like the AVCR due to its complexity and thoughts that a bigger solanoid is better. Which is untrue. ;)

 

EDIT: Stock turbo or not.. It has nothing to do with it. A good EBC will hold boost. i.e the rb20t turbo was able to push 16psi at 7000rpm on the rb20det when with a crappy bleeder it would tapper off to 12.5psi. You need an intelligent EBC. AVCR, Blitz SBC-id or the Greedy E0-1 (Expensive) I think it is.

AVCR lets you do everything. :cheers:

fuzzy logic, rpm & gear based boost. everything.

GReddy Profec B-Spec II, or even a Spec-S...

I don't know I would have to read up if it has a boost curve learning mode.

If you simply dial in a number say 42 or 45 that has no correlation to the boost figure

its self then it is based on a percentage of maximum boost hence duty cycle.

That is when you will run in to trouble as you cannot get the boost controller to increase or reduce the duty cycle when needed to hold a certian boost.

you will never be able to sustain 17psi throughout the entire on-boost rev range with a 2530 on an rb25. 2 different tuners in here in SA explained from their experience that apparently there is too much exhaust flow from the rb25 at the top end, where the compressor is "spun out of its efficiency" and starts to "chop" the intake air rather than compress it. we were also running 17psi and it always dropped off to 13psi at the top end. in this case, its the turbo, not the EBC that is responsible for the pressure drop. Before we we're told this we had tried 2 different wastegate actuators and 2 reputatable EBC's, all to no avail.

just be happy with the mid-range :D

a HKS EVC 3 or 4 will give the best control out of all of em...

but doesnt offer the fancy stuff like Gears vs Boost... guess thats why they are $150 cheaper. No flashy shit. Just controls boost you ask for

you will never be able to sustain 17psi throughout the entire on-boost rev range with a 2530 on an rb25. 2 different tuners in here in SA explained from their experience that apparently there is too much exhaust flow from the rb25 at the top end, where the compressor is "spun out of its efficiency" and starts to "chop" the intake air rather than compress it. we were also running 17psi and it always dropped off to 13psi at the top end. in this case, its the turbo, not the EBC that is responsible for the pressure drop. Before we we're told this we had tried 2 different wastegate actuators and 2 reputatable EBC's, all to no avail.  

just be happy with the mid-range :D

But i was thinking i could run 17psi in the midrange and when it starts to drop, somehow try and squeeze more boost into it without trying to boost to more than 17 in the middle.

Mate you can up the boost all you want but with a 2530 all ya gunna do is make hot air. And all that will do is bring you that bit closer to detonation.

and you know this because why?

do you know where a 2530's Efficiency range is?

its certainly not at low boost - 10-15psi. HKS turbos are designed to perform better at higher boost... not just "make hot air"

How good of a boost controller do you consider something like a GReddy Profec B-Spec II, or even a Spec-S?

Greddy Profec Spec S is like the old Profec B just with an upgraded solenoid.

Profec B Spec II is a bit of a pain to set up.

Check the link bellow, its bit old but good info.

http://www.sportcompactcarweb.com/tech/020...boostcontrol05/

Mate you can up the boost all you want but with a 2530 all ya gunna do is make hot air. And all that will do is bring you that bit closer to detonation.

no offense, but i dont think youve had much, if any, experience with 2530's on rb25's, because if you had, youd know that you cant "up the boost all you want".

not trying to shit stir here, but im coming from direct experience in collaboration with 2 reputable SA tuners.

Mate you can up the boost all you want but with a 2530 all ya gunna do is make hot air. And all that will do is bring you that bit closer to detonation.

no offense, but i dont think you've had much, if any, experience with 2530's on rb25's, because if you had, youd know that you cant "up the boost all you want". if you have had experience with this setup, i really want to know how you did it, because it was a real pain in the arse :)

i think if it was capable of sustaining 17psi at the top end, after all the tuning and trying different things, we would have been able to make it happen.

now on a rb20, its a different story, smaller engine, less exhaust gasses. my good friend with a 2530 on his r32, making 240rwkw, can sustain up to and over 17psi across the top end.

not trying to shit stir here, but im coming from direct experience in collaboration with 2 SA tuners.

But i was thinking i could run 17psi in the midrange and when it starts to drop, somehow try and squeeze more boost into it without trying to boost to more than 17 in the middle.

it seems to be all due to excessive exhaust gasses. i've always thought that if you enlarged the wastegate, you would be able to bypass more exhaust, slowing down the exhaust turbine and hence bring the compressor back into its efficiency. does that sound right?

i know its not all about the exhaust turbine and housing that matters, but, we have a 2835proS on the 25 now and both the exhaust turbine and its housing is considerably larger than the 2530, and it sustains 17psi rock steady across the top end, and wants to keep going. its so easy to hit the limiter because there is no letting up in the power delivery. after a rebuild it would be interesting to see if we could find the point, if there is one, where boost drops off at the top end with this turbo. but i dont think id like to push it that hard :)

But i was thinking i could run 17psi in the midrange and when it starts to drop, somehow try and squeeze more boost into it without trying to boost to more than 17 in the middle.

it seems to be all due to excessive exhaust gasses. i've always thought that if you enlarged the wastegate, you would be able to bypass more exhaust, slowing down the exhaust turbine and hence bring the compressor back into its efficiency. does that sound right?

it seems to be all due to excessive exhaust gasses. i've always thought that if you enlarged the wastegate, you would be able to bypass more exhaust, slowing down the exhaust turbine and hence bring the compressor back into its efficiency. does that sound right?

The wastegate on a HKS 2530 is bigger than the stock R33 turbo, i guess its still not big enough.

Does the 2535 have a bigger exhaust wheel than the 2530?

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

    • The average previous owner for these cars were basically S-chassis owners in the US. Teenagers or teenager-adjacent. I often tell people that neglect is easier to fix than something that was actively "repaired" by previous owners.
    • Update 3: Hi all It's been a while. Quite a lot of things happened in the meantime, among other things the car is (almost) back together and ready to be started again. Things that I fixed or changed: Full turbo removal, fitting back the OEM turbo oil hardlines. Had to do quite a bit of research and parts shopping to get every last piece that I need and make it work with the GT2860 turbos, but it does work and is not hard to do. Proves that the previous owner(s) just did not want to. While I was there I set the preload for the wastegates to 0,9bar to hopefully make it easier for the tuner to hit the 370hp I need for the legal inspections that will follow later on. Boost can always go up if necessary. Fitted a AN10 line from the catch can to the intake hose to make the catchcan and hopefully the cam covers a slight vacuum to have less restrictive oil returns from the head and not have mud build up as harshly in the lines and catch can. Removed the entire front interior just shy of the dashboard itself to clean up some of the absolutely horrendous wiring, (hopefully) fix the bumpy tacho and put in LED bulbs while I was there. Also put in bulbs where there was none before, like the airbag one. I also used that chance to remove the LED rpm gauge on the steering column, which was also wired in absolute horror show fashion. Moved the 4in1 Prosport gauge from sitting in front of the OEM oil pressure gauge to the center console vents, I used a 3D printed vent piece to hold that gauge there. The HKB steering wheel boss was likely on incorrectly as I sometimes noticed the indicator reset being uneven for left vs. right. In the meantime also installed an airbag delete resistor, as one should. Installed Cube Speed premium short shifter. Feels pretty nice, hope it'll work great too when I actually get to drive. Also put on a fancy Dragon Ball shift knob, cause why not. My buddy was kind enough to weld the rust hole in the back, it was basically rusted through in the lowermost corner of the passenger side trunk area where the wheel arch, trunk panel and rear quarter all meet. Obviously there is still a lot of crustiness in various areas but as long as it's not rusted out I'll just treat and isolate the corrosion and pretend it's not there. Also had to put down a new ground wire for the rear subframe as the original one was BARELY there. Probably a bit controversial depending on who you ask about this... but I ended up just covering the crack in the side of the engine block, the one above the oil feed, with JB Weld. I used a generous amount and roughed up the whole area with a Dremel before, so I hope this will hold the coolant where it should be for the foreseeable future. Did a cam cover gasket job as the half moons were a bit leaky, and there too one could see the people who worked on this car before me were absolute tools. The same half moons were probably used like 3 times without even cleaning the old RTV off. Dremeled out the inside of the flange where the turbine housing mates onto the exhaust manifolds so the diameter matches, as the OEM exhaust manifolds are even narrower than the turbine housings as we all know. Even if this doesn't do much, I had them out anyways, so can't harm. Ideally one would port-match both the turbo and the manifold to the gasket size but I really didn't feel up to disassembling the turbine housings. Wrapped turbo outlet dumps in heat wrap band. Will do the frontpipe again as well as now the oil leak which promted me to tear apart half the engine in the first place is hopefully fixed. Fitted an ATI super damper to get rid of the worn old harmonic balancer. Surely one of the easiest and most worth to do mods. But torquing that ARP bolt to spec was a bitch without being able to lock the flywheel. Did some minor adjustments in the ECU tables to change some things I didn't like, like the launch control that was ALWAYS active. Treated rusty spots and surface corrosion on places I could get to and on many spots under the car, not pretty or ideal but good enough for now. Removed the N1 rear spats and the carbon surrounding for the tailpipe to put them back on with new adhesive as the old one was lifting in many spots, not pretty. Took out the passenger rear lamp housing... what do you know. Amateur work screwed me again here as they were glued in hard and removing it took a lot of force, so I broke one of the housing bolts off. And when removing the adhesive from the chassis the paint came right off too. Thankfully all the damaged area won't be visible later, but whoever did the very limited bodywork on this car needs to have their limbs chopped off piece by piece.   Quite a list if I do say so myself, but a lot of time was spent just discovering new shit that is wrong with the car and finding a solution or parts to fix it. My last problem that I now have the headache of dealing with is that the exhaust studs on the turbo outlets are M10x1.25 threaded, but the previous owner already put on regular M10 nuts so the threads are... weird. I only found this out the hard way. So now I will just try if I can in any way fit the front pipe regardless, if not I'll have to redo the studs with the turbos installed. Lesson learned for the future: Redo ALL studs you put your hands on, especially if they are old and the previous owners were inept maniacs. Thanks for reading if you did, will update when the engine runs again. Hope nothing breaks or leaks and I can do a test drive.
    • No those pads are DBA too  but they have colors too. I look at the and imo the green "street" are the best.
    • I’m not sure what happened I told them about sonic tunes free OTS tune and the next the I know .. I was booted..   To funny 
×
×
  • Create New...