A guy over on d-series.org posted a comparison of his setup after he swapped out his normal single collector manifold for a twin scroll manifold (done properly with 1-4 and 2-3 joined).
Same engine, same twin-scroll Holset turbo (HX35) and on the same dyno. The only other difference besides the manifold was an increase in boost, he went from 25 psi to 30 psi.

I overlaid the 2 dynos so the difference was easier to see.



One thing to consider is that the divided inlet of the turbo probably didnt flow very well when used with a single collector, which may have had some impact on spool, but regardless, the gains are impressive.

 

I've seen many twin scroll plots on other platforms, much less drastic than this one, but solid gains nonetheless. looks like either the turbo or the setup is out of breath already, but yeah this is a shockingly drastic improvement.

 

Yeah, its either running out of turbo, or hes pulling excessive timing with the added boost.

Pretty impressive for a 1.6L with just rods and pistons. Especially considering most people think theyre pointless to modify, haha

 

The HX-35 came in quite a few different trims ranging from billet comp. to many different turbine housings. The rule-of-thumb for a 9 blade HX35 with the 12cm^2 turbine is 550-600whp at full tilt. Depending on application, of course.

That dyno is pretty damn cool. I'd love to get a powerband like that from my HY-35, just a 1000rpm to the left.

 

Take note that you can also achieve spool gains like this by actually tuning your boost control. This generally is unimportant if you're running a tiny turbo that spools at 600rpm but for any medium or big turbo it is very important.

 

Comparing the slopes of the curves I'm pretty sure both instances the boost was tuned. but yeah, wg spring vs mbc or ebc the difference is insane

 

Go ahead, boost your 1.6L and try to get those results. I'll pay you $1000 if you can make your Mazda B6 output like that with just rods and pistons.

 

I think hope he was talking only about the hawnduh 1.6L

 

That 2.5k long powerband is most excellent.

 

oh yeah, I talk about modding honda motors on the miata websites all the time.

 

Yup. Because all 1.6's are basically the same..duhh

 

wanna race...



until 4.5K?

 

Look at that crazy torque before 4.5k

the blue line car would obviously win at autox...ask techsalvager

 

I still laugh at the fact the dyno run starts at 4k and ends at 7.5k. I bet on the highway from a roll that setup is a blast, but for general driving around town I would probably hate it.

 

Dudes, this is a civic.
Moving that torque to the left would be seriously pointless unless you drive around on full on drag slicks. Even then, I have personally been in a EG civic with 500whp that spun huge slicks aired down to 12psi past 70mph on the street. Its stupid.

That's all those cars are used for: freeway pulls*

*unless fully built slicked out and prepped for traction which is extremely rare.

 

Give a B6 8:1 CR and 30 psi and it would probably lay down some big numbers too.
Im not sure how far of it would be, but this is a D series not a B series. People dont think these engines can make any power either.
But yeah, I put this in the BS section for a reason.

 

still doubt it. I've seen plently of built, low CR, B6s struggle to breach 300rwhp.

 

I don't think ANYONE doubts the honda D series anymore. After Bisimoto and others started slapping giant turbos to them and making nasty numbers thats basically a thing of the past.

The Mazda B6, on the other hand, still has yet to prove its not a total POS

 

wtf, my B6 is awesome

 

Don't hate it until you drive it. It looks like it's fully spooled about 1000rpm later than where yours would hit 30psi. My GT3071 hit 30psi at around 4500rpm. Speaking of which, your mani should support the VE (unlike my log which choked above 19psi) so 30psi could provide beneficial gains. Only one way to find out.

I have 9:1 pistons. Why do I suck. Gotta send my turbine to Abe today for my turbo crane.