Hks2835 Pros, .63 Or .86 On E85?

[75coupe]

currently i have a hks 2835 pros .63 turbo getting 290rwkw and great response on pump98, what kinda difference in response and top end would i be looking at if i went to the hks pros .86 rear housing but on E85.

Will the E85 help cover the slightly less response of the larger housing?

How much more top end would could i see with the .86 housing and E85 over my current setup?

Any help appreciated

[ARTZ]

I'd try .63 housing and just e85 tune first..might pick up an extra 30kws...more power and more response...it will keep your housing cooler than petrol too and will have heaps of torque...however a .63 housing can only flow so much...

As for bigger housing I dont think you will pick up alot extra from it as your compressor will max out, e85 might help your response a little bit and what you do lose in response you will gain in midrange torque..

290 is good numbers...alot of guys with 3037s still are barely getting that

[discopotato03]

The Pro S housing sizes are 0.68 and 0.87 , I think the hot side of many GT based turbos is the limiting factor in units designed to have good "response" .

My preference would be flow over ethanol in that sized turbo , not cheap going down the road of bigger injectors pumps and thirstier consumption . I don't recall people saying 0.87AR 2835 Pro S were super laggy things and for a long time they were hard to beat power and response wise . IMO changing the housing and tuning it is easier and cheaper long term .

Ethanol may get you another 30 wasps but restriction is restriction and keeping the timing up longer doesn't alter that . By restriction I mean at higher power levels for that housing on that turbo . If you keep up with the Hypergear thread Taos found that std manifolds and IWGs tend to be the limiting factors with bolt on turbos and I don't think it's any secret that gas speed is usually higher through a smaller AR housing and at a certain velocity it isn't real keen on doing a 90 degree exit out the IWG . Total flow in an IWG housing includes the waste gates share and if you have a smallish one with a high rate actuator/controller forcing the flap shut then restriction and manifold pressure tends to be a power limiter .

The GTRS on my 25 was a PITA till I worked out that the boost control wouldn't let the valve open and was choking the engine under load at 21-2300 revs . Having a bit of extra flow here obviously reduced the manifold pressure and allowed the engine to breathe and rev past this point .

Your calls but I reckon the roads to "response" don't necessarily start with smallish IWG housings and don't let the gate open boost control strategies .

Now the cold side of a 2835 Pro S is not exactly wimpy for what it tries to do , the hot side was expressly designed to be an easy bolt on that gave good response and quite reasonable power output . Having alternate turbine housings gave you the ability to lean towards power or response for that size turbo .

[ARTZ]

I kinda got the feeling he was running EWG..

[75coupe]

Reading discopotatoes response confused me a little i had to read it three times to kinda understand it..

Im just thinking that at 21psi and 290rwkw if i can get a bit more top end with the larger exhaust housing with e85 it should keep the heat down whilst gaining a bit more...?

So possibly 40kw us increase and lower exhaust temp???

Does that sound right, i have the larger injectors and rail ready for e85 tune, just thought while im at it go the larger hot side if im getting a tune? IWG for sure at this stage until i go a different turbo altogether

[ARTZ]

you also have to consider how much more boost you want to put in it...I mean 21psi is already pretty much in its efficiency zone...and yes while e85 can gain more power this is often because it allows you to run more boost with things detonating.....there will be small gains from the fuel itself no doubt but how much extra boost are you really willing to run and is it worth pushing it past its efficiency...

I'm sure a few more pounds wont hurt it but Just something to consider

I'd want to try a e85 tune first then if still not happy upgrade the housing...but i guess that depends how your tuner is charging you too, if hes charging for a full retune everytime you change something well its not that attractive to keep making changes to your setup...

Also believe .87 housings are near impossible to find...

[wolverine]

there is one for sale atm (at least there was the other day)

[75coupe]

Having one for sale on the forums is what made me ask the question...

And upgrading the housing when i go to e85 is also to save tuning cash hence why i ask that question.

Thanks for the replies, but i must admit im still kinda confused, more boost isnt an issue if the tune is good, but less choking on the exhaust housing has to be good as long as minimal lag increase, e85 mid increase may cover that...

Yep still confused... Thanks for the input though.

[AngryRB]

looks like its been done before:

http://www.skylinesaustralia.com/forums/topic/389417-300kw-unopened-25-club/

not sure what size rear housing though, I think you'll notice the extra lag with the larger housing, I never had any decreased lag

converting to E85.

nice 33 by the way.

Edited February 19, 2014 by AngryRB

[Dale FZ1]

290rwkW from a 2835 Pro S 0.68A/R running on pump 98 is a very strong result if it's an unopened motor with no internal airflow mods.

Upsized housing will change the character of the engine with not so much flattening out after 6000ish rpm, and a little bit longer to gather its skirts down lower. On pump 98 I'd think you will effectively move the torque band upwards 500rpm with the power number bumped 10-15kw tops but only if everything is optimal.

A GTX based compressor would allow higher and more efficient flow than would the GT unit you have, so I'd have to suggest the existing unit might sneak another 10kW top end (6500rpm plus) and maybe 15-20kW across the mid range (4000-5500rpm) by going E85 with the existing compressor.

Go search and I think you'll find Mick_o hit around 340rwkW on E85 with a GTX3071 0.82 A/R setup with 25ish psi boost. By way of comparison that unit has a higher flowing compressor that is also more efficient at high boost. You might get near that result but don't be shocked if it doesn't/can't.

The improvement from E85 isn't just a bigger top end number, it livens things up substantially in the mid range.

[ARTZ]

you will also find Hamish was running 325kw @ 21psi on a pro s with e85 ...so theres def alot more than 10kws to be had in it

with e85 and an extra 2-3 psi I picked up 40kws and 80-100nm everywhere from 4000-6500.....admittedly there may have been more in my pulp tune but its still impressive..

if your turbo is all bolted up and working well, why unbolt it...just fill tank with Ethanol and tune..if you're still not happy get a bigger turbo alltogether..

[Dale FZ1]

Hamish had a good result. My sums from changing housing and fuel suggest somewhere around 320-330kW. But I'll stick with the notion that it's a stretch to get there. The 2835 Pro S is smaller in what I consider the critical dimensions vs the GTX3071 Mick-o ran. Stands to reason it will work harder to get to the same mark - smaller compressor inducer, smaller dimensions for the turbine so it can't flow quite as well.

If OP wants more, yes I'd agree a complete turbo spec change could be warranted. A Pro S housing won't be easily found. Running E85 might just put the whole shebang in a happier place and give him the desired result.

[GTScotT]

IMHO the entire outcome will benefit from E85, so I do not think the results will disappoint without the housing swap. If anything they will be even better.

It should be noted that Simon runs a 3076 .63 on his RB30. A 50mm gate and E85 keeps it happy, along with a sensible rev limit.