Hi all
Can anyone tell me how much air the rotary engine flows at given RPM\'s
Say, 2000, 4000, 5000, 6000, 7000 etc
This needs to take into account air temps as well.
I have found a few websites for other makes of cars and some that cover the 4 stroke engine but nothing giving info on the rotary.
Any help much appreciated.
Ta
I could be wrong (it\'s been known to happen frequently) but I think this will depend on the map and should be visible on the PFC commander in the settings menu.
no idea what stock is tho.
Do you mean as in CFM\'s???
Fish
Yeah CFM coming from the Exhaust ports.
Its in relation to my other post about turbo specs, I am just trying to decide which one will give the performance I want (not too laggy and still quite capable of breathing a fair bit)
I already have a T70 BB turbo left over from my previous car that never got fitted so I might give that a whirl??
Also, could do with knowing the VE of the rotary too?
Cheers
hi im new here, no rx7 or real tuneing experience, but if you are after lots of technical stuff like that, best to talk to a reputable tuner
Hi Wiggy,
Why do you want to know?
If you explain that I will be able to give you some input.
Kind regards
Carl
Hi Carl
I am basically wanting to know this for the purposes of single turbo installation.
Many people have recommended turbos but me being a nosy git ;) and the type of guy that has to know everything before going ahead with it. Not because I\'m a git or anything, I just love to learn new stuff and finding out about the rotary is key at the moment. Having worked on and tuned 4 strokes for yonks, the rotary represents a new challenge for me :D
So, learning what exactly is going on and then making an educated selection is my aim.
To do this however, I need more info about the way the rotary works and what differs to the average 4 stroke jobby in terms of Exhaust gas flow to the turbo.
Any help mucho appreciated
:D :D
Well,
I have only so far met 1 person on car lists and forums who can read a turbine map. So you may be stuck with the old fashioned empirical approach.
OK,Here goes.......
1. The 13b rotary has a chamber volume of 654cc per rotor chamber.
The power pulses are the same as for a 4 cylinder piston engine.
So that means effectively that on the inlet side of things you need a compressor that can handle the equivalent of a 2600cc piston engine.(654cc X 4 =2616cc)
BUT and it is a BIG but,here is where the rotary is a little different to a piston engine.....
The rotaries ability to breathe is very good,it can and does go over 100% in Adiabetic volumetric efficiency in N/A form,so as a rough guide,consider the 13b rotary to be able in an extend side ported mode to be able to breathe the equivalent of around a 3 litre piston engine.
2. The exhaust side of the engine is also displacing the equivalent volumes of burnt gas that a piston engine of the higher cc region is producing,from the above rough,and I mean rough amounts I have suggested.
There is one important difference though with the rotary engine that must be taken into account for turbine sizing,that is that the exhaust gas is much hotter than a piston engine,this means that the gas is at a much more expanded volume than it would be for the equivalent piston engine and so travels faster too.
The turbine GENERALY for a rotary has to be around 20% bigger than an equivalent piston engine in order to acommadate this phenomenon.
It is also vital not to strangle the exhaust gas with to small a turbine or it will mean that the inlet charge becomes contaminated with exhaust gas under certain conditions.
I hope that this is helpful.
Kind regards
Carl
Fandabbydozzy :D
So in general terms:
A: Large turbo required (Similar to Skyline and Supra specs for optimum flow?)
B: Roller bearing to aid spool up and cooler running at higher RPM
C: Highly efficient exhaust and intake to promote optimum flow from said turbo
D: Large wastegate (50mm?) will this cause surge?
These are the basics I had in my head before starting out on this quest :D After that explanation from Carl I am hopefully on the right track?
So, theres no perfect setup, but we can get dam close. I suppose I will just have to stick this turbo on I have and see how it goes :eek:
I always like to over do it on the specs so you have a nice safety margin. The way I see it is a turbo overworking it bad no matter what. Stay well within the turbos capabilities and things tend to work better for longer. I\'ve seen it many times before in the past. People over working std turbos seems to be at epidemic levels at the moment in most clubs :rolleyes:
Cheers all, keep up the debate :D
A.Correct,compressor slightly larger than the cars mentioned
B.Roller bearing is best route to take ,it aids the large turbo to spool up quicker.
C.Correct,especially the exhaust,although it is hard to keep the noise down with good flow,it can be done though.
D.Correct,larger even if possible.Depends on power really though.
You should be ok with surge.
Send me the measurements of the turbine outlet on the turbo you have.
Also are the blades cut back?
Kind regards
Carl
Hi Carl
This is what I have
Wet floating ball bearing
Turbine SHAFT & WHEEL TRIM 64.5mm
COMPRESSOR WHEEL SUPER 70 60.5mm
TURBINE HOUSING A/R .84
COMPRESSOR HOUSING A/R .70
Not sure about the blades, will have to check :D
QuoteOriginally posted by Carl
C.Correct,especially the exhaust,although it is hard to keep the noise down with good flow,it can be done though.
D.Correct,larger even if possible.Depends on power really though.
You should be ok with surge.
Geff\'s 10-second car is now 4" stainless front to back and makes lots of power :) and is fine to drive even without an interior - compared to the previous exhaust of circa 3-3.5" which was the usual head splitting droner even with a full interior that FDs usual come with! As Carl says, u can make a big power FD reasonably quiet, you just have to try.
Get a wastegate that is a reasonable size and proven to work on rotors; the big HKS gates 50mm+ are well reputed. The smaller Turbosmart Progate is used on a lot of very high power aussie drag cars with goood results. Get the 48mm version that they do now over the 45mm...