No worries- I apologize if I offended you for having that info on there-

I will ring you tomorrow- on dyno testing some turbos-

Subaru motors get killed from many things unfortunately- they arent robust at all unless thoroughly built!

As with anything its a balance of everything-

cb

 

If someone here wants to say that the twin scroll doesn't improve threshold boost over a single scroll setup, they're either lying or incompetent. I've tested this back to back with the 6758 and the 7163. It's a huge difference.

 

Interestingly in simple regards to turbo sizing-

we just tested the 6758 back to back with a 7163 for Borg Warner- on an evo X-

they spooled almost identical- the 7163 just makes more power-

Transient response and so forth is improved to some regard on most twin scrolls- but again in regards to packaging- overall power output, cost, etc- the open scroll stuff has suited us well for years

Hey eric- werent you the one that ported out the twin scroll volute into an open scroll on an FP stock housing?

cb

 

Not an Evo, but at least one person has done back-to-back testing on a 7163 SS vs TS on an STI: http://forums.nasioc.com/forums/show...2640508&page=3

I'd gladly take that extra 25% torque at 3000RPMs and the additional transient response over the extra top-end of the SS setup.

From the link:
The guy later rebuilt the motor and did some more tweaking, then pulled an incredible 544HP and 625TQ out of the motor. Insanity.

The single scroll makes a lot of sense for top-end applications that don't need transient response, but I'd still take the twin scroll any day for autocross or even DD.

 

are the results posted somewhere?

 

While I know that response is important, the disparity b/w 2.5-3.5k and the slight differences b/w 3.5-5k do not outweigh what happens after 5k-redline. If you're looking at the graph, its pretty much a wash b/w 3.5-5k anyway so, on the average, from 3.5-7.5k (which is a 4k powerband), you'd trade the extra 30whp and superior torque up high for 1k of powerband? I dont understand...

 

I have to compile dyno charts- off of the transient respont, mpg and shift testing (2nd through 4th at a set start stop speed on both)

We were a little disappointed that the 6758 didnt shift the curve at all- just lost power- because we wanted to run two of them on our GTR- now we are pretty set on two 7163's-

however- to satisfy the questions/masses- we are building a 7163 TWIN SCROLL IWG setup for the EVO X that will bolt up to our current downpipe and other bits- so it will be an option if people want it- however we will- like almost always- choose the open scroll vband setups for our clients/builds-

cb

 

you are also dealing with a motor that has more displacement (another half liter) over a typical evo setup-

again-

TS versus open have their benefits and drawbacks!

our evo 8/9 RBX kit is a 7163 Vband EWG setup with new tubular manifold and recirc'd watercooled tial wastegate- but we can also bolt a tial or garrett vband too it- however we are LOVING the EFR stuff- plus we havent seen surge issues like the all primary blade GTX turbos in these flow ranges-

cb

 

Thanks appreciate it - at the end of the day, I will say that my interactions and experiences with Chad and CBRD have always been very professional and that his 7163 kits does makes excellent power.

 

Thank you sir! sorry for any issue!

cb

 

Dyno graphs will show the general powerband but never show the transient response of the turbo. If anything, if you play enough with dyno loading, you can get very laggy turbos to show impressively wide powerbands that are just not attainable on the street.
One thing that builders never show, is the real life boost response when you step on the throttle suddenly. I did some tests on the HKS 7460 kai and will compare it to 7163 T4 TS when I build up that one, as I am more interested in the response than 20 Whp on top..

 

Oh I know. I own a mustang md-250. They do show a bit of transient response on my dyno as I can simulate a run going through the gearing. If you keep the same parameters on everything you strap down, you can make comparisons on the same dyno. I dont think you can adjust this on a dynojet... If you ask me, if response/powerband is within 10-20% of each other pre-3k, I'd much rather have the hp up top. When you're racing, its not often you'll be at sub 3k rpm's anyway...

 

well, that depends on what kind of racing you like to do. For straight line it is simpler.. with no lift to shift you get great boost recovery on any turbo.. hell it is instant..
What I like to know is how is how quickly boost gets back when I go off the throttle before the corner.. lets say at 5500 RPM and then floor it back on after a couple of seconds at 4500 or 5000... this is a realistic case I have on the road or roadcourse..
A nice comparison here is the stock turbo vs. something like the HKS... which is signifficantly faster on boost than the stock turbo in such cases, although their dyno plots are very similar on paper (not on the max numbers of course, but in the points where it goes on boost)

regarding the dyno games by some tuners I was shocked to hear that some well regarded ones like to hold the engines at fixed RPM for a few sec at the begining of the run, at full throttle, and then release them for the run... this is an easy way of moving the begining of the graph a couple hundred RPM to the left... MAke no mistake, big manufacturers do the same thing.. official dyno plots are done at very slow ramp rates..

 

I agree with you but for a road car, or a road + some track, I like to have a car that works properly low down.. i.e. starts boosting somewhere like stock.

This means that for 2.0 litre I am limited to smallish turbos like hks 7460, and I am secretly hoping that 7163 in TS version, with a nice tune will work like 7460 low down, have same transient response, at least, and give 30 or more hp up top... Tough list I know..

 

The Evo 8/9 needs some loving in TS as well! We need more info on the Evo 8/9 kit especially in this section of the forum.