Hello tuners,
Last days I have read this forum a lot! As You may guess its all about compound turbo! I know it's been spoke out here many times, but still I have my questions and will have.

I drive a Honda Civic Shuttle Beagle, it has 1.6l sohc vtec engine for my build. It's a small engine and I really don't like turbo lag, so I decided to try this setup. Really weak information about this setup on honda engines in the internet. If I do this, I will be one of a kind with such a setup like my car is very rare.

For the start I am hoping to get around 300 whp and very fast spool. Engine will be build to hold up high boost pressure, so it won't be a problem.

I am now at the very beginning and I am searching for proper turbochargers.
So my first question is about the sizes of both turbos: my thoughts are, that they should be perfectly balaced togeather, but how it would work if one would be very small and the second much bigger?

Till now I have found that the small turbo could be Mitsubishi TD03, it would make 18 psi on 1.5k rpm and is capable to hold the efficiency till 4.5k rpm, so that's the point where the second turbo should start working. Here is a compressor map with my points:



As I read in forum, than I should copy these points to the second turbo map. One guy is selling Garrett t04e-04 40 trim compressor A/R .50, turbine A/R 1.0 (twinscroll). Here are the points on garrett's map:


To get my HP goal I decided that I need 22 psi on the garrett and this how the map looks from 4.5k-8.0k rpm
(But this one is calculated on 1.6l engine)



It would be nice if someone could explain me how to correct calculate second turbo map, because I read, that the engine volume changes because of small turbo.. If I change engine volume in my calculations to 2.0l engine, than the flow changes about 5-10 lb/min and than this t04e gets too small..

I have another chance to buy Holset HE351, but it's twice expensive than Garrett, but if it's worth it, I can wait one more salary and buy it

And one more question about wastegates, I was planning to buy 2x 38mm tial.. But now after reading, I start thinking to get 2x 44m???

Oh, and is ported shroud obligatory for the small turbo or it would be necessary for both turbo's?

That's it for now! Hope for Your support, because this is the best forum where to ask this stuff!

Maybe someone could move this topic, where it belongs, because it looks like here it doesn't belong

Really no one can help?

I am guessing that no one is going to help you set up your honda because this is a DSM site, try posting this on a honda site. They will know your setup better than DSM guys.

I already said, that there isn't any info in honda forums, I have checked out a LOT!
If I would know that You guys don't help other car enthusiasts, I wouldn't mention that I am driving with Honda! I am just honest person.
I am one of local honda club member, and we don't regret to help other people, also if it's not a question about honda!

Maybe someone could just tell if this is true:
If my engine exhaust flows aprox. 170 cfm, the small turbo should be capable of 340 cfm and the big one 680 cfm ?
Just YES or NO?
ps. got this info in "turbochargers" book