Porting options for rebuild?

[suba]

As mentioned in another thread it\'s rebuild time.....

I\'m considering going for a large Streetport - or should I go half / full bridge?

The car is not used on the road much, though it is a road legal car - and i would like to be able to take it out at weekends.

Is a bridge port going to make it too much of a pain on the road?

Another thing to consider is the choice of turbo - I\'m hopeing that I can get away with running my BNR stage 3 turbos non-sequentially, and stick with my HKS / Racing beat exhaust - which is plenty loud enough for me, and also most track day noise limits.

If a bit of a tip has nuked the turbos then I\'ll go to a GT35R or GT40.

With either option I want the car to have good response, and come on boost nice and early rather than a big peak bhp figure.  So what do we think would be the porting to go for?

The rest of the setup is taken care of as far as cooling and fueling is concerned, and clutch is an exedy hyper single plate.
:Thumbs-up

[m1tch]

If its for the road then go for a large streetport, its what im going for and I will be running a T88, anything above a large streetport will obviously mean the idle suffers and you lose the power low down.

I would suggest a large streetport so that it give you the extra air and exhaust flow you need and still keep it drivable

[lee mills]

I run a full bridge and have no problems on the road with it but i would say with the info youve put up to go for a large streetport should be more than sufficient for your needs

[m1tch]

I run a full bridge and have no problems on the road with it but i would say with the info youve put up to go for a large streetport should be more than sufficient for your needs

Much brappage

[Kash_]

Go J Port

[arrouk]

after running a half bridge for the last few years there are good arguments for and against.  They can behave quite well on the road and if driven with a little practice can be smooth enough but when you put your foot down OMG. The main 2 draw backs are they are thirsty, very thirsty and the noise which can be controlled but isn\'t as easy as you would think.

I would speak to your chosen engine builder as I\'m sure they will be able to get you a test ride in various cars, or go to one of the meets in your area and ask the members there for a ride.

Matt

[suba]

Another thing to consider is that I would like to keep my HKS downpipe and racing beat exhaust to keep the noise down for trackdays.

Would that be too restrictive for a bridge port?

J-port is out from the research I have been doing.  If you would recommend one could you explain why, and what the pitfalls are?

[BlitzBoy]

dont go bridge if you keeping the Twins it will outflow the manifold and you will find it hard to maintain a steady boost level as the wastegate would be too small even when its ported.

If you are driving on the road and using it for trackdays (not competition) go for a large streetport. Bridge ported motors take a lot of effort in keeping them quiet enough to be allowed on most circuits.

Dont listen to Kash he is only joking. A J port is an extreme form of Bridge porting where by the seconday hole eyebrow is made very large port goes into the water jacket and devcon is used.

[suba]

Thanks Mark - you have PM by the way....:Talking1

[m1tch]

Also if you keep it with a large street port there is still some plate to actually let the corner seals on :rollin

[rx7boy]

Suba sent you a PM response, My recommendation is go with large street port.

http://www.mazdarotary.net/porting.htm

[Kash_]

Mark shut up man you\'re a killjoy

SuBa sounds like a large large streeport is your best bet for what you would like... maybe stretch to a half bridge but not past that

[batman]

i have a large street port and use it every day mate its fine i wouldnt go bridge unless its tracked just to much effort to stay in the red line on the queens highway lol

[suba]

Thanks for all the replies - does anyone have an idea of what kind of power increase I could expect from a large streetport, and moving the BNR\'s to non-sequential?  I was running 330 at the wheels on stock engine at a bar sequentially.

Bryan at BNR says 400 at the wheels is achieved regularly - which is quite a jump in power!:xconfused

[mx1311]

i have a 3" holesaw