Hks 2535 On E85 Power?

[Joshbigt62r]

Hi guys just wondering what you all reckon a hks 2535 could make on juice bolted to a rb25 with supporting mods? I'm thinking of getting a retune for e85 in the very near future and was hoping I could maybe snag 270rwkw out of the little huffer.

Cheers Josh

[R31Nismoid]

Given they are a small turbo and run out of airflow on 98, top end gains won't be as major. You will get midrange gains none the less as you could put more boost into the midrange, but it will still taper off and with it the top end power if the turbo is already falling off.

Where E85 excels is being able to run more boost AND timing than you can on 98 in the top end - which is where the top end power gains are as a combination. You also get midrange as well of course as added boost earlier beefs everything.

[Joshbigt62r]

Thanks for the detailed information r31nismoid. Basically answered everything in one.

[Dose Pipe Sutututu]

I've owned the same turbo, great little unit but aiming for 270kW could be a tad optimistic.. it might be possible I think but that rear exhaust housing would be glowing red enough to roast chooks off. Unless you're game enough and externally gate it to move the heat from the turbo, reduce exhaust restriction (as that rear housing starts choking the motor) and pump some jungle juice through the motor.

[Lithium]

What kind of power are you guys making on pump gas with that turbo? Remember that E85 gives a big gain, even without any more boost or strain on the turbo...

[Dose Pipe Sutututu]

I previously cracked 246kW on Hitman's dyno... but the tune wasn't that great.. knocked on load, I pulled timing back on rows 15~18. Realistically this turbo would be good for around ~235kW without shooting the exhaust temps through the roof.

[Lithium]

There is a pretty good chance that 270rwkw would be doable on E85 then, imho.

[Dose Pipe Sutututu]

Yeah but the little tiny rear housing would choke up the motor...especially since it is internally gated.... probably if it was externally gated I reckon there's a better chance.

Would be good to see if anyone has tried it

[Lithium]

What I mean by that is with the turbo doing EXACTLY what it is doing now, it shouldn't need to move any more air (ie, no more boost) or generate any more heat for that power gain. If anything, I'd have thought it'd be able to do that power and DROP EGT with the use of E85.

[Dose Pipe Sutututu]

fair enough, because you're pumping in more timing so less heat it generated.

[Joshbigt62r]

Well I'm currently making 235rwkw on 14psi on createds dyno in Melbourne. So I was hoping to make 270kw at the wheels on jungle juice. Maybe I should try running a external gate off the housing maybe. Or what suggestions do you guys have?

[Joshbigt62r]

Would it be worth putting a billet wheel from a gtx series turbo in it like a gtx2867 compressor wheel. I really like the hks 2535 on the street. Maybe I should just sell it off and go top mount gtx 3076r

[Lithium]

What ECU and injectors do you have? If you aren't after monster power and mostly happy with what you have but just want to up it a bit and you have the ECU and fuel system to support it this is what I'd do:

a) Tune it on E85 - raise the boost until it is clear you are starting to lean on the turbo, don't let it totally max out or anything - just go to the point it's obviously going past it's best from there. If that is still only 14-15psi at peak power, so be it. A reasonable tuner will be able to see the VE curve at that boost level isn't holding up like it was when the turbo wasn't maxing out imho.

b) Take stock of the injector duty cycle at peak power - this will also give a reasonable idea of how much pumping the turbo is doing.

c) Decide what the most boost you want to run on the engine you have

d) Calculate a new boost curve based off how much head room you have in injector duty cycle - clip it by your maximum boost level, then adjust the boost curve to suit. If you choose 21psi as your max then you may end up with a boost curve which holds 21psi up to 5000rpm then gradually drops down to 14psi at 6400rpm.

e) Tune to suit the new boost curve, profit!

This way you should potentially be able to avoid making the turbo dropping boost of it's own accord so it isn't killing itself to do what you want it to do, you should be able to deliver power like a car making >270kw on an RB25 through much of the rev range, and TBH I reckon there is a reasonable chance you'd be able to make 270kw on E85. I've done this with a car before and driving the car on the initial flat boost curve and comparing it with the "new" boost curve (was avoiding maxing out turbo and injectors in this case) the car felt like a totally different beast - much much quicker and more fun to drive, despite making exactly the same peak power.

If I was given a car previously tuned to 235kw on 14psi and asked to retune on E85 then I'd be thinking to myself that there was a good chance it was about to go over 270kw but there are always variables and you can never know till you've tried it. For what it's worth I've tuned a RB20DET which had a knock limited 240kw @ wheels on BP98 to make 295kw @ wheels on "E33" at the exact same boost level - no other changes at all. Knock limited setups are where ethanol comes into it's own.

If you're thinking about doing an upgrade have a good think about what you are willing to live with next!

[R31Nismoid]

What kind of power are you guys making on pump gas with that turbo? Remember that E85 gives a big gain, even without any more boost or strain on the turbo...

As i said earlier - not always a "big" gain as more results are coming out with smaller turbo setups as generally they are not limited in the top end. Midrange, yes of course - no argument there at all

Look at RB26s with -9s/-7s - to date not one guy that's gone E85 has achieved anything more than a ~15rwkw gain in the top end as the turbos have already fallen off 3-5psi by 8000rpm as they are past efficiency on PULP. I know I could add +5 timing to the top end of my map and not make anymore noticeable power (or knock) in the top end with the smaller turbos on the same boost level as it wasn't knock restricted.

Where a -5 setup will pickup a solid 30-40rwkw almost certainly as you can also jam a few extra pounds of boost into it.

[Lithium]

Haven't tuned such a setup yet, which is why I mentioned all cases aren't equal - but I specifically mentioned that the cases I'd seen those gains were with no more boost.

[R31Nismoid]

I think most would say 45rwkw just with not even 1psi of boost is probably far and above the norm, and E85 is making up for other issues and not necessarily the turbo related.

It's like when I was using Sunoco 104 over 98 with a really bad exhaust. Managed 270rwkw on 18psi and it wouldn't take a ounce more with the exhaust on (drop it more power no worries), put 104 in and 370rwkw on 24psi was the end result with exhaust connected.

[Joshbigt62r]

Well I might just suck it and see. The set up is forged rb25

JE pistons

Eagle rods

King bearings

Plazmaman plenum

Hks intercooler

Sard 850cc injectors

Vipec plugin

Hks pod

Bosch o44 custom drop in

Ect ect ect.

Im extremely happy with the way it performs as it is for now. But e85 will would be nice to try. I think I may go top mount in the near future. And drop some poncams in.

[Joshbigt62r]

I wonder when how boost a 2535 would take before really pushing it to hard. I'd think 16-17psi would be near the limit???

[R31Nismoid]

It'll fall over in the top end as the 2530 always did (And the 2535 isn't massively different).

What you could do though is certainly run more boost through the mid range, 20psi+ wouldn't be out of the question as long as the turbo can flow the air really

[Dose Pipe Sutututu]

I ran 1.4bar into mine, it tapered off to 1 bar.. the housing was red enough to roast some chooks

even at 1.2bar I think you're going past it's sweet spot, remember they're quite a small turbo... and with that motor you have there, why wouldn't you just slap a bigger turbo on?