Porting questions...
 

Ok i know i'm gunna get bitched out for not searching the forum for the answers i need, but i have for the last half hour, and had most of my questions answered, but i still have a few.

Half bridge vs full bridge, how often would i need to rebuild?
If i'm building on a S4 turbo and am shooting for 500 to 550hp reliable daily driver engine, is a full bridge really necessary?
Also would like a 9k redline for track weekends, besides necessary balancing and bearing changes, which port job is best for this ?

Thanx for the help guys, is nice to have a place like this where i can have these type of questions answered by the experts.

an aggressive street port is best for what you want....

Wow only one reply

i'm sort of a newb but i'm not sure you can have a 500-550hp RELIABLE daily driver 7. i could be wrong tho, wouldnt be the first time.

i would also assume that an aggressive street port would work for that power range depending on your other modification plans.

we need a little more detail to let you know what kind of power you will be able to make. its a combination of parts, etc. that will allow you to speculate the required porting in order to achieve your power goals.

unelss there is something I am missing, 550 hp DD (using 93 octane) is going to be almost impossible. I don't consider a daily driver to have meth injection.

Good luck.

Its going to take some money but i would like to send my engine to racing beat (or another place, recommended by forum members) to have super lightweight rotor assembly, type 2 modified stationary gears, or 3 window bearing (do i need both ?) Race exhaust porting, full aluminium housings, race clearencing of rotors, engine balancing, flywheel balancing and pressure plate balancing. And either half or full bridge. RtekV2 Stock turbo, with modified housing and wheel.

I don't mean to make 550 daily, thru the use of multiple fuel and ignition maps and a good boost controller, i would like to street it at around 300 to 350, with option of going all the way up to 550

550hp as a daily is possible on pump and meht injection. there are people who do daily drive full bridges. The more hp the make the more its going to cost you. If you are trying to get 550-600hp you might want to look into an engine swap to a 13bre or a 20b, the s4 block has been known to fail.

Ohh, i may just have to lower my expectations. i could settle for 450, i'm only 21 now, so its gunna take alot of saving. tho i will own a 20B FC before i die

Any recomendations on places to have engine work done that may be cheaper than racing beat ?

I'd do aggressive street port plus water injection if you're worried about daily drivablility and engine longevity. Bridge ports are perfectly drivable but not "daily drivable" (practically speaking). They lack low end power and fuel economy. Even off the road and onto twisty tracks the low end power is supposed to be a problem. A half bridge is halfway daily drivable. Alcohol injection will give more power than water injection but it corrodes the engine. Lower the compression ratio if you can to help you boost safely. Also tune extra rich, plenty beyond what you need to stop detonation. Sure, it doesn't knock now, but later your engine goes pop in an instant. Likewise keep up on fuel system maintenance and upgrades to prevent a lean condition and keep up on turbo system maintenance.

For 9k redline: RB mentions different items u need and so will a forum search. I saw a 12k rpm pport with balanced rotors, raised oil pressure (100-120psi), carbon apex seals, race (er/ing?) bearings and maybe more. The RX-8 uses balanced rotors, those same bearings, and an improved lubrication system (maybe it's the extra OMP injector?). It's all about improving the rotating parts.

Racing Beat and Mazdatrix are the big names people like. If you go elsewhere you might risk poor quality. Not saying it can't be done both well and cheaper, I'm just saying be careful. Sorry I dunno where to go though.

i don't know his prices, but shoot BDC a PM if you're serious. i don't know him, but i am a big fan of his work. also, i believe he's pretty much next door to you (in Texas). he will be able to sort you out in terms of setting goals - what's realistic and what's not.

good
 

I have a S5 N/A GTU, if I just want to change the stock port to street port, how much would it cost me?, am I able to do that and keep all the orignal stuff? how much hp will be producing? anyway please help out. I like rotary engine especially porting them.

i agree with some of the things you said and disagree with others. anyway, i just want to comment on one.

although i don't really believe in the "daily-driver-bridge", i just want to offer that if he's running normal aspiration, then low end issues would be true to an extent, but if he's turbocharged, it shouldn't be an issue. if someone has a REALLY soft low end with a turbo bridge, they probably didn't match the right turbo to the engine or the tuning is not optimal, or both. in this day and age of engine management systems and turbo choices, low end shouldn't be an issue.

the gas mileage-thing is right on the money though ... :)

the s4 breaks at 350-400hp at the flywheel. Found this out on the track over a year ago. rear side housing cracked in 3 spots on the dowel landing, and the last 3/3" broke off of the dowel. Yes, it broke. And oil sprayed everywhere. Had it towed home. series 4 rear irons suck

Go the Extended port. Its as reliable as a streetport, but makes more power cos of the larger intake and exhaust ports.

I'd get a larger turbo, large FMIC, full exhaust, programmable ECU, decent transmission, bigger injectors and a high capacity fuel pump.

To do a street port you will need to tear the block down, if there are no major problems you can re-use everything but the seals and springs. As far as cost goes, its cheaper to do it yourself but you need a die grinder. To have it done it would probably be 1.5 - 2k for a rebuild with street porting.