Peripheral ports

[kiwimazda]

Hi Ray, long time no speak. Yes you are correct. Might be able to change his shafts but I am sure Grant has that all under control. And I just remembered I got the diff from you I think??? At a bit more than £50.

[Will66]

Emissions make no difference to whether or not a car is safe to be run on the street, it\'s just enviro-bunkum!  I like seeing in-date tax discs on the cars in the JDS Street Series.  Particularly when someone says "Not his best run" on an 11 second pass which you\'d need a Mclaren F1 to match!

I look forward to seeing an RX4 on the strip, that will look very cool.  A 10 second run from it will look even cooler!

[Grant Monkhouse]

Emissions make no difference to whether or not a car is safe to be run on the street, it\'s just enviro-bunkum!  I like seeing in-date tax discs on the cars in the JDS Street Series.  Particularly when someone says "Not his best run" on an 11 second pass which you\'d need a Mclaren F1 to match!

I look forward to seeing an RX4 on the strip, that will look very cool.  A 10 second run from it will look even cooler!

Well I do hope to please. Will you need to get yourself to the fia European dragsters main event or finals. 10 seconds is nothing, even for the street legal classes. If I remember next year I will remind you when the event is on so you can get your ass down there with me.

[Will66]

I am going to try and get to Flame and Thunder and I will book my time so I can get away for the FIA meets next year.  I fancy smelling that Nitromethane and then mentally spending money I don\'t have on some drag beast!

[Grant Monkhouse]

There was a drag bike for sale there. £8,000! 7 second passes.

[- Fezcat -]

Just out of interest - Whats the usual cost for a set of P/P housings?

Ive seen figures of about £1000 per housing thrown about? I guess you\'ve got to have the other ports filled in in the front/centre/endplates too?

[Mir]

I m not an expert!! But 1000 pounds looks too unrealistic, thou I may be wrong!

Cheers
Mir

[Will66]

I\'ve heard of £2500 for pukka Mazdaspeed PP housings.  I could be smoking something funny though.

[- Fezcat -]

Is that for a pair or for a single housing

[Grant Monkhouse]

There are Mazda "race" housings which have more material which can be removed from the housing to give even bigger holes.

Don\'t know prices though.

[rx7boy]

There is a company in Canada that will do ceramix coating and porting for less than that for both housings. They did the coatings for the 787b so think they have earned their reputation.

[HaywardRotary]

There is a company in Canada that will do ceramix coating and porting for less than that for both housings. They did the coatings for the 787b so think they have earned their reputation.

That is not true about doing the ceramic coating for the 787b I am afraid, just someone trying to capitalise.

If I am supplied with the housings I can do them.
If I supply good used rotor housings then it\'s more of course.

Regards
Carl

[Grant Monkhouse]

Mazda race housing on the right

Can anyone explain the reason to the shape of the port?

[Miki]

Mazda race housing on the right

Can anyone explain the reason to the shape of the port?

If you mean exhaust port its pretty simple. this shape gives most flow from least area. If someone think that bringing edges of bottom of the port to the same opening height will give more flow, is wrong, it actually hurts flow. Same applies to port roof but not with such magnitude.

Answer why this isn´t applied to stock engine lies in fact, that manufacture is concerned with low load fuel economy, so they cannot port for big overlap. Only way to make sufficient port area was to make ports wide on bottom.

Point is that anytime you make port bigger, even without affecting timing, you will make engine less flexible and more picky with big chance that you will gain nothing, but loose quite much.

Just imagine how long is exhaust port opened in rotary engine and take into account that big holes also like to flow backwards:Nono!

[Grant Monkhouse]

i did actually mean the shape of the inlet port, not the exhaust port.
 
it is god to see the difference in the 2 housing exhaust ports here too though, lhs housing you can clearly see the exhaust sleeve. rhs housing it looks as if the actual exhaust sleev is made of th same stuff as the housing and is actually part of the housing, aluminium straight through.