originally posted here:

http://www.rx7club.com/showthread.php?t=442934



but i know this forum has a lot of people that know stuff about engine building. i always read, never post. anyways:



ok, so i am planning to do an engine build, and right now i am just trying to finalize what i want to do.

this will be my first rebuild, done over the winter (6 months or so). i am not going to be using the engine that is currently in my car (i don't drive my car anyways in the winter), so i can make this a slow and meticulous process.



this discussion is about the 6-port non-turbo route, using a S5 13b.

my PRIMARY goal for this project will be to get a solid 200 whp



i don't see any way of getting this number without porting, which brings me to a major issue.

i had originally thought that an aggressive street port could yield this output. and yes, i have HEARD of people getting these numbers, and there are some that will argue it's possible. however now i personally don't think a streetport will cut it. so this is the main thing i'm trying to figure out.

so that leaves bridgeport i guess, but this opens up a whole can of worms, lol.

i'm still learning a lot, and have been playing around with a lot of ideas. one method that interests me is doing an agressive steetport on the primary and secondary ports, and then doing a bridge on the auxilary ports (is this what some people call a 1/3 bridge?). i'm not quite sure though if there's anyway to to retain the stock aux port system so that they still remain closed under a certain rpm? this would certainly help with the idle and also maintain the a good low end powerband.

what about those Euro-spec 6-ports? i heard they don't use sleeves...hmmm...



i have also been playing with the idea of using RX-8 or beveled rotors to get slightly more intake opening. maybe this would help get 200whp just on a streetport?



thinking of TII housings, since the exhaust port will be much easier to work with, and i can port it nicely...



there wouldn't happen to be templates for an aux port bridge, would there?



other issues:



engine management - i need SOMETHING for timing control...originally thinking of standalone (Haltech), but could i possibly use the e-manage with full fuel and ignition control? (i can get the e-manage for cheap...).



intake manifold - does the 1/3 bridgeport require a custom intake manifold? or even rather will it only run well with one?



AFM - i'm thinking this becomes an issue at this point? or maybe not, there are TIIs running 200whp+ with stock AFM...this is of course dependent on choice for engine management, but could influence whether a standalone is REALLY needed



drivetrain - will the stock NA transmission and rear end need to be replaced with something stronger? i want try to keep the weight down as much as possible, i don't feel like putting in the heavier TII components...



fuel - can the stock injectors and fuel pump handle this power level?





so anyways, i'm just looking for some advice and comments. the porting is definetly the most confusing and intimidating aspect of the build. hopefully i can get some junk irons also for practice...i'm interested to hear how others would go about getting the stated power goal from a 6-port.



thanks

- Aaron

 

look in the 2nd gen timeslip and dyno section on the evil forum

 

[quote name='kahren' date='Jul 13 2005, 07:55 PM']look in the 2nd gen timeslip and dyno section on the evil forum


[/quote]



yeah, i know that YOU were able to get close to 200 whp, and again, great job . but it's not exactly easy.

one part of me just wants to go streetport and settle for that, and hopefully get it to run as well as you have. do you have a thread that goes into the porting you did in more detail?



but the other part of me says what the hell, just do a bridge on the damn thing. that way there may be 200 whp, and THEN SOME



oh well...i think the biggest issue for me is the whole custom intake manifold thing, i really don't know too much about that. anyone care to explain?



- Aaron

 

MY goals are about the same with the same questions. My car doesn't need to be legal. I also plan on a stand alone. Are there any after market intakes that would work well with a bridge port (efi). I'm still trying to figure out the whole port timing thing. If you keep the bridge short so you don't change the timing much just increase flow will this add to power with out moving the power band up?

I'm still searching but would welcome input on custom intakes.

Has anyone tuned their headers I'm still not sure about a few of the variables but it seems like most headers were desighned to match up to the cat and not to match the power band.

thanks

Dave

 

unless the bridge is WELL made and is large it just doesnt work well. you get what you pay for?

 

there's really no way to do a bridge without drastically changing the port timing.



the bridge makes power through timing, the streetport makes power through flow (and a little timing)

 

if the bridge doesnt flow its not gonna change ****

 

too true

 

sorry guys I'll get this figured out some day. SO if I want to make peak power at around 8k what would be better extended port or bridge port 1/2 1/3 ? I don't want to make all of the mods to build an engine that will survive 9-10k. At what point do I need to make a new intake? If I pull the exhaust sleeves will it hurt my power in the 5-8k range?

Dave

 

Kahren just looked at your dyno sheet nice job. Do you mind sharing runner dia. and length. I can't argue with the results, but did you do the math the runners seem short.Is there a reason you didn't use a plenum ? After seeing your numbers I'm making an intake. For basics on intake construction check this out http://www.turbonation.com/intake.htm

Thanks

Dave