Progress

It is done except for the WG and O2 sensor. I am considering putting the O2 in the DP..Thoughts??
I may have it on my 86 uncoated tomorrow night .

Here a couple of pics

 

I had mine (WBO2) in the DP, some 15 cm from the flange. No problems.

 

Yeah Mike I've heard that internal w/gs are not as good yet as Adam points out, perhaps with E85 there may be more margin and there are some guys using these things and pushing out some pretty decent psi/power.

 

You dont want to have wideband sensors installed preturbo anyway.

 

G-lad to be of service mon ami. Occasionally even an idiot like me can come up with something.
I like the pics too. As a really rough guess what do you twin scroll guys think will be the results in the amount of earlier spool? I mean it's not going to be 500rpm better is it? Surely not. Is earlier spool really the only reason to do the split pipes / turbo? I will be interested in your findings.

 

it might be more torque produced per psi during spool up as there is less cross pressuring of the cylinders from each other . Also perhaps more top end from the bigger size of the new cross over pipes .

 

Ok, well that's worth the effort then. I guess it's going to be hard to determine the advantage unless you do a proper back to back comparison?

 

wide band will stay where it is, after DP. I am just talking about the O2 sensor

 

I was told, when I bought my Holset ( which is twin scroll ), that using divided exhaust will drop spool at least 300 rpm. That reason alone is enough for me to use it. Unfortunately I didn't get that far... But, after seeing Sid's results later, I might be able to speak the guy that bought my running gear into getting an exhaust like that.

 

Patrick,

I "think" it will make huge difference. One thing is the size of the turbine housing is smaller that will reduce it for sure. AS mentioned upthread thetwin scroll housings should be bigger to get the same flow as open, again I am going smaller and twin scroll, which may be too much. I am tempted to go ahead and just move the flange on my current crossover. I may still.

From what I have been reading the twin scroll reduces spoolup between 200-500rpms.

Right now with this head it is hitting 15psi at ~ 4k

I am hoping the twin scroll will get it down to ~3300 and then I can put the other head back on and maybe it will be below 3k...wishful thinking probably.

My other dilema is that I have 4 of these Holsets ranging from a H1c (supposedly 450 hp) to a HX 40 pro wheel (supposedly flows 72+ # per minute, very nice ). I have an H1E on right now that is supposed to flow 60+ per minute.

Can't decide which to use, I am leaning towards the Hx 35 (500hp) b/c it has been proven to spool quicker and will support over 500 hp on twin cammers so it will probably be fine for my DD. It also uses the anti surge flute that supposedly helps make power earlier (my current H1e also has it and it does make some noise).

OTOH, to get and absolute comparison I should stick with the H1E.

I am looking to run it at ~ 450 or so, but with spool coming on ~ 3k.

 

Well I'll stay tuned for the results. I do like some push in the back type turbo thrust, but 450-550whp coming on in a semi linear shove should be pretty compelling no matter what. I know it makes more sense to have a smoother delivery and moreso on the track, but I love seeing a break in between cars up ahead and timing the boost kick to slice through them....yup there's just something about that which gets me everytime

 

Yeah, I can't tell you the amount of internal gates I've ported out to try and get rid of cracks causing them to leak. Followed by them receiving major stress fractures in the housing down the road (there's a surprise). Granted I've seen canyons on totally stock ones as well.

 

it's not like its impossible to mount an external wg to it later though.

love the idea, I was originally going for it before I bought my tialsport GT30R, and then kinda bought a v8

the holsets are awesome, used in a lot of stuff "up north"

my buddy with a miata 1.85liter with ported head +++ work etc has BOOST at 1800rpm with a GT30R 0.63..... our engines really are crap compared to thoose 16v things.

 

Thinking out load once again .

Does anyone here think it would be worth it to dyno both open and TS crossovers same hotside?

I am thinking about it.

I have decided to use the current turbo since I am very familiar with it right now

 

Well it would definitely be worth it but whether you can be bothered. In terms of research and reference it's good to know what difference you're going to be making.