This might seem a stupid question...but as i am unsure so thought i would ask.
What does porting actually consist of. Reason being is i have the engine stipped down at the moment (FD3S) and i want the engine street ported ready for my single turbo conversion. I was wondering if i could give the job of porting to my mate who is a full qualified timed served engineer. He has done piston engines in the past but never a rotary. This is a long shot.....but is there a description or How Too, on the net anywhere. Or am i best just taking it to pip????
Cheers
Adam
Hi Adam,
If your not sure you would definitely be better off taking it to someone like pip to do. Quite a few rotary engines have suffered premature failure do to bad porting even by specialists.
What turbo you going with ? you want the port and the turbo to compliment each other. What you aiming for as far as power from the car, what will it be used for. All these question + more need to be determined first and then you select a turbo and porting to match your needs. Let us know what your plans are.
rgds
My plan is to port the engine now then but the engine back together close to standard....bar exhaust and air filter. Run the engine in then, once i have the funds go for either a GT35 or one of the apexi RX6 kits (larger turbo). Basically i thought it would be a good idea to run the engine in this way then do all the mods?
Cheers
Adam
Wouldn\'t make any difference bolting everything on now and running it in as long as you not trigger happy with the right foot.
If the turbine housing is too big on the turbo whether a garrett GT series or an apexi rx6 your gonna take ages to build boost and it will get on your nerves, If your only gonna use the car for dragging or something then it doesn\'t matter that\'s why I was saying what you want to use the car for ?
If the turbine housing is too small you\'ll have very minimal lag with good low down punch but run out off puff up top. Depending on the type of porting you have also will have a big say on power band and drivability etc.
rgds
cool.... thanks for your help.. The car is going to be a street car so turbo lag is an issue. I guess this is something i need to discuss with pip so he can do the right kind of porting.
Thanks
Adam
You don\'t want to port the primaries then as you will have no low end. Turbine a/r housing want\'s to be a maximum of 1.00 a/r .84 or .96 would probably be better suited for street and less lag.
Last but not least try and go for a turbo which is rebuildable and not too hard on your pocket to rebuild, as turbo\'s that are canned regulary don\'t last forever and some are a lot more expensive than others to rebuild.
Best of luck with the project.
rgds
QuoteOriginally posted by BNA_ELLIS
You don\'t want to port the primaries then as you will have no low end.
rgds
Bit of a sweeping generalisation there IMHO. The stock primaries are pathetically small and will take considerable cleaning up and enlargement before any losses under 2000RPM are noticed, Especially if a single conversion is on the cards.
Also remember that there are 3 aspects to porting. Runner size, port size and port timing. All of these have an effect on the power band in a different way, and not one that is entirely well documented.
QuoteOriginally posted by bill shurvinton
Bit of a sweeping generalisation there IMHO. The stock primaries are pathetically small and will take considerable cleaning up and enlargement before any losses under 2000RPM are noticed, Especially if a single conversion is on the cards.
Also remember that there are 3 aspects to porting. Runner size, port size and port timing. All of these have an effect on the power band in a different way, and not one that is entirely well documented.
I guess it is a sweeping generalisation!!
If the guy has never played with a rotary engine before and wants to port the engine. Without going into the ins & outs of porting he needs to know what ports he wants to be playing with in his case the secondaries, that what I meant.
rgds
fairynuff
I\'m not sure about this as i didnt port my engine with the twins on it, i put a single on it when it was built, But i think the stock twins will not work well with a ported engine unless it is very mild. The wastegate cannot control the boost and you may end up with boost creep and spikes that cause a lot of grief. The way around the problem is to port the wastegate which is all more work which will be wasted if you then change for a single.
My advice if you could afford it would be to do everything at once, it will be cheaper in the long run, also its a hell of a lot easier putting the engine back in with a single and an apexi as you cut away half or the wiring loom and you can throw away all of the little solanoids and vacume pipes. Also you wont have to have it remapped everytime you change something. As you have probably already gathered you will have a hard job taking the twins while the engine is in the car so you will also save a lot of labour.
As for porting, it was my first rebuild and i matched the primary\'s to the secondary\'s and did a little exhaust porting. A lot of people have said this is strange but car drives really well and with very little lag. My car idles perfectly and pulls really hard all the way up the rev range. It ran 12.5 at the pod last weekend with only 14.5 psi of boost.
In My opinion you can play with the ports quite a bit.
The primaries can definitely be played with.
You will not lose hardly any low down torque if you do this correctly.
As Bill say\'s the area,timing and runners are what matter.
As Antony say\'s he has opened up his primaries to the size of stock secondaries with no problems.
I personally do many variations on porting depending on customers overall build spec and budget.
For a single to breathe really well porting is the way to go,but it is not essential,if you do no porting then you will lose some top end but gain only a little at lower revs what you would have with a ported engine.
You can get considerable power gains from porting and running stock twins,you just need to map correctly.Just look at John Yorkes power figures.
Kind regards
Carl
Bill you have PM.
RGDS
Here\'s an interestinglink on porting types. Probably doesn\'t help you much though!
http://www.autospeed.com.au/cms/A_0389/article.html