huee

iTrader: (2)

Hey guys, im new to the rotary scene, back in the days, i used to have a 86 gxl, loved it. After my turbo honda days, im getting back into rotarys. I have a chance to pick up a non running turbo 2.

Now to my question. Coming from working on turbo honda's street/strip etc(heck we got my friends civic into 10's on a stock block, ) im curious about turbo sizing. I have been reading up here and there and it seems like the t4 size is the the basic starting point for a turbo upgrade. Why arent the t3/t4 hybrid turbo's used? do they top out too soon? I mean, i would thing it would spool up faster, reason being, i have a practically brand new precision sc61e turbo, and that thing is good over 400 hp, which i think is pretty good for a street set up. Now i dont claim to be an expert, im far from it, that said, im pretty familiar with what makes power for what with the 4 bangers. But any info on this matter would be greatly apreciated.

RacerXtreme7

iTrader: (2)

The rotary has more dissplacement then you think (1.3 ltr or 80cid). Basically double the dissplacement and get close to what it inhales and exhales compaired to a piston engine (2.6 ltr or 160cid). That being said, its exhaust is close to a 2.6 liter v6, but more. Sinse the port is a gaping unrestricted hole its exhaust pulses are like Mike Tyson upper cuts. That being said it needs to breath freely also due to the port overlap to keep too much exhaust reversion going back into the intake cycle. Now you have an engine with hellafied exhaust engergy and needing to be reletively free flowing. A T3 sized turbine just is too restictive for any respectivly large horse power numbers. it'll spool hella fast, but it will fall on its nose in the mid/top ranges. Also, running a ultra quick spooling turbo isn't as great sounding as everyone thinks. Boost while cruising is just a plain waste of gas and more uneeded strain on an engine. If you search more, you'll find that a typical turbine trim used is P and Q trims with turbine A/R's in the .81,.96 open valute ranges and .84, 1.00, 1.15 A/R values for divided valutes (turbine housings). These sizes are absolute "No NO's" for 4 bangers unless strickly drag, even then I don't think you'll see such large turbine trims matched with those turbine housing A/R's. Which trim turbine and A/R values are based on the compressor size and the cars' owner's expected boost response. Just another note....... because the rotary has such a strong exhaust pulse, there able to swing and spool up LARGE turbo's compaired to piston engines.

And for those just dieing to chime in with such misinformation as "but the GT35/40 {aka: GT35R} has a T3 hot side", or "But the Apexi RX6 has a T3 hotside" do your home work. They have larger then T3 sized turbines (actually P-trim sized or a tad smaller/larger) and have pretter big A/R values and ONLY uses a T3 inlet/ bolt pattern.

~Mike..........


~Mike................

RacerXtreme7

iTrader: (2)

FWIW, "hybrid" in the rotary world generally means a stock turbo with an upgraded comp and or turbine, not the well known in other communities T3/T4 "hybrid".

~Mike............