Boost on the rotary

[BinoX]

One of my more mechanicly minded friends was talking to me about my RX7 and my future plans for it. We got talking about turbos and such and he asked me how much boost pressure the rotary could take.
 
He was under the impression that it could take more pressure than a normal piston engine due to it\'s design. So I said I wasn\'t sure and would ask here.
 
So I have a couple of questions on this...
 
Assuiming a standard, non-ported 13b S5 Turbo II engine.. If you had good enough injectors, rails and other related stuff (and obviously an aftermarket ecu) how much boost pressure could the engine take?
 
The second question is.. Assuming that the engine was to be modified. What\'s the maximum theoretical boost it could take and what mods to the engine would have to be made? (including specialised seals etc if required)
 
(If either of those questions are too hard to ask, could someone tell me what the maximum boost that has been used on a 13b that we know about)
 
Thanks in advance

[Prof]

I know of a few 13B\'s in the US running upto 21 psi (1.5 Bar ?) but I think most of those engines are ported.  I am not sure how much difference the porting would make to the engine\'s ability to take the boost - most of the work that needs doing is strengthing the engine (dowellng, etc.) and you are going to have to be very careful with detonation and the extra heat when you run that much boost.
 
Not sure how much higher you could go...

[BinoX]

Thanks prof
 
I personally am not planning on going anywhere near that, it was just a theoretical conversation. I\'d say the most I would aim for is 1.2 bar.. but even that is unlikely. Most likely going to be around 1 bar eventually.

[m1tch]

Thanks prof
 
I personally am not planning on going anywhere near that, it was just a theoretical conversation. I\'d say the most I would aim for is 1.2 bar.. but even that is unlikely. Most likely going to be around 1 bar eventually.

Stock injectors = 0.9 bar = engine ok and about 300bhp
uprated and supporting mods = 1.2 bar = engine ok = lots more power lol

Basically a rotary can run 1 bar all day every day if its set up and is looked after, another above 1.2 bar is where the engine life reduces quite a bit, but 1.2 bar is a good place to be at as with the common turbo upgrades like the T04z or simular you are looking at near enough 500bhp

[BinoX]

Yeah, not really had a serious look into modding yet. I do have a basic list of the kind of thing I\'m after though, so I\'ll play with the actual specs later.
 
Not too concerned about engine life, I\'m probably not gunna do more than 3000 miles a year in it, so if it needs a rebuild after 15000 miles or so I\'m not too bothered so I can go nuts, lol
 
More concerned about getting the rebuild done on currently limited funds. Looking to get it going by August (ready for time off work) and then from August (when cash flows more freely again) will be looking at fuel system, turbo, intercooler... etc etc lol

[m1tch]

Just make sure you have all the supporting systems in place like fueling etc etc and make sure you have gauges to check what values are where for any trouble and you should be fine

[BinoX]

Yeah Will do
 
I\'ll probably spec something up once the rebuild is done and post it on here and ask for opinions if you guys don\'t mind
 
But I\'ll probably do it in stages anyway... Starting with a new ECU one month, then fuel system the next and so-on until it\'s all done
 
Thanks for your help

[papercutout]

As implied by mitch, it\'ll be much better for you and the car/engine if you hoard bits and do it in big stages. E.g. turbo upgrade - do injectors, fuel pump, management etc all at once, rather than an item at a time.


And have lots of gauges to stay safe :p

[Furb]

my S5 non ported engine has handled 1.3bar without breaking...
BUT i have bigger injectors and it is mapped properly!
 
it is really been mapped for 1bar, but due to really low intake temps lately i had issues with creep. luckaly, everything above 1.1 bar it is set so rediculously rich, it just kills the spark so it skips a beat instead of exploding.