jjandros

iTrader: (7)

Ok So I'm right in the middle of my build and my goal is to squeeze 200 HP from a S4 13B N/a.

First off I know all of you guys have mass amounts of knowledge on modifying N/a engines so I'm starting here. I want pure n/a power instead of going to a hybrid turbo.

First question is If I run a large street port or a bridge port can I run the OEM ECU? Will it find idle and just be a little lean at higher RPMs until I run a standalone? If I was to build the engine the exact way I want it should peak at 230- 250 HP and Redline between 8K -9K RPM. Obviously with a larger port I won't see power until higher RPM which is Exactly how I want it. Recommendations or links to previous builds on how others achieved this is greatly appreciated. Thanks to all that actually take the time to read this.

-Jay

diabolical1

iTrader: (3)

are you planning to keep it 6-port or are you going to change to 4-port? also, just for clarity, are your desired numbers at the wheels or flywheel?

at the wheels, breaking 200 is not an easy task, but it has been done by quite a few people over the years. just know you will probably have to ditch the stock ECU and likely the intake manifold as well. streetport or bridgeport is your choice. you'll have to weigh the pros and cons with what you plan to do with the car.

running a streetport on the stock is ECU isn't really a big deal, but you may need something else (piggyback) to optimize it. for bridges on the stock ECU, you'll want to search for Judge Ito (either here or on youtube - i can't remember) and there was a gentleman from Montana (i can't remember his screen name off the top of my head) that did one recently as well. if i recall, he posted some youtube videos as well.

for the 200 HP stuff, do an advanced search with Kahren in the subject and my name in the "user" box. i remember doing a thread a few years ago where i posted a few links to some 200 HP cars.

jjandros

iTrader: (7)

I have 5 full sets of s4 n/a irons... so I'll definitely be sticking to 6 port and port widening, I'd like to just do a large street port while utilizing solid corner seals just in case there's even a HINT of overlap. I want to try and use the stock ECU for a while until I can afford a standalone.

Goal is 200-250 HP *225 at fly wheel is my goal, a little above or below is fine for this build. Trying to retain streetability while upping peak power output to 4500-7500 RPM with an 8000-9000 RPM redline. The exhaust will be all built be me except for the headers and mufflers. Emission will be deleted and cats will ne... gutted to say the least. As for intake, fuel, injectors, and standalone I have no idea what i need to do to reach my power goal.

diabolical1

iTrader: (3)

Tougemonster was the other member's name i couldn't think of.

that power at the flywheel is not unreasonable. it can be achieved, but as i said, you have to decide if you want streetport or bridge. my guess (and that's all it is) is the streetport will net you up to the 220s. i think i remember seeing one or two people around 240 (give or take) on streetports, but neither of them we 6-ports if i recall correctly. anyway, as i was about to say, i think anything over the 220s will have to be bridge. again though, keep in mind you'll probably have to ditch the stock intake manifold at some point to get there.

i see that you have another thread going and you said that you intend to keep this as a street car. you will have some decisions to make once it's built and running. i'll stop posting here and let others share now.

jjandros

iTrader: (7)

Definitely will be keeping it as a streetcar. And as for those thinking that it won't pass emissions and sound I have that covered. All I have to worry about is to keep it Looking legal. I'll be using solid corner seals so I Could go bridge but would rather keep a little bit of power in the lower band. The intake manifold will probably end up being corksport or racing beat ( I'll have to call them both and ask what kind of port job they used during flow testing). 220 at the flywheel would be perfect.

j9fd3s

iTrader: (3)

well you need to address the following stuff, not presented in any order

exhaust: the engine header port match is important, RB headers don't match up very well, but there is enough meat to port em. the exhaust ports are about 48mm, and the header is 44mm... the stock manifold is 50mm inlets. i like the stock manifold on a street car but 200hp is a lot to ask...

the stock piping is 50mm ID, which seems to be a good size, going to 60mm ID is probably a good idea for big hp. Mandrel bends are probably a great idea. the mufflers should be straight thru, or dynomax makes pretty high flowing turbo style ones.

header primary length might be important, the RB is 32", the old school setup is like 90" or 24-26" and then 50 is popular now, if you're really looking for big hp, you may have to cut and try.

ignition: CDI on the leading is a good idea, or if you change the ecu running 2 leading coils, the waste spark is a waste... i like the stock Rx8 spark plugs, but there are a few choices here, and stock plugs do work fine as well. the trailing ignition seems totally fine.

ECU: getting rid of the AFM is good, being able to tune the thing is good, and being able to run a better ignition is good, so its worth the $$$

intakes: i do not think a stock intake manifold flows enough for 200hp. if you insist, at least port match it.

engine: the more new parts you use the better it will run, it makes a difference. since the 6 ports close so late, the advantage seems to be to open the primaries earlier. i'd be tempted to port it to the stock Rx8 opening. the pineapple/atkins 6 port sleeves are good too. the exhaust ports are fine, but turbo sleeves are a good idea (or just buy new turbo rotor housings, its $$ but new housings make more power than crappy old ones.

the S4 rotors are ok, but the 9.7's are a little better.

for running @8500rpm, you should look at the Rx8/FD stationary gears and bearings, along with the turbo oil pump, and FD oil pressure regulator. balancing is a good idea. even if its the low $ version, of cleaning all of your rotors and picking the two that are closest to the same weight.

IMO, a great street combo would just be a stock exhaust manifold into a 50-60mm exhaust into free flow mufflers, port match the intake, and then tune it with an AFC/rtek

jjandros

iTrader: (7)

j9fd3s: Thank you for your response. I'll be loooking through all of your info and taking notes (literally). Do you recommend just building the headers myself since I'm alredy doing the rest. Also, do you recommend merging both pipes to one exhaust or to build a full length free flow dual pipe sytem? As for the intake the filter is no problem and I'll end up port matching the intake manifold.

j9fd3s

iTrader: (3)

i've never seen anyone do a back to back with a dual vs a header, so i'm not sure how that would go. i've seen both work well.

the RB header is fine, it just needs a port match, and if you get experimental you can play with different lengths.

my street car is just a stock FC manifold, into some port matched cats into an HKS catback, its not fancy, but its quiet, and actually passes smog.

the track car has a port matched RB header, and when i get around to redoing it, i'm just going to buy some pipe from RB, and some clamps JEGS Performance Products 30850 JEGS Stainless Steel Lap Band Exhaust Clamps and just try a few different lengths, and see what the engine likes.

you certainly can make your own header, the bend coming out of the engine on the RB headers is a little sharp, but i think just matching it to the engine, and finding the right length gets you 90% there.

jjandros

iTrader: (7)

My worry is is to make sure that flow is equal through both exhaust ports. I have a spare stock exhaust manifold and think I may try cutting off just the gasket side and bend equal pipe lengths just bigger than the exhaust ports all the way to the rear. My worry is the weight and sound that it'll make. My mufflers right now are some cheap ebay freeflows that don't muffle worth anything. If I decide to merge to a single pipe then length/ volume/ flow become really important especially with every face of the rotor possibly make slightly different compression (Wish I had the tools and money to go titanium ha). My last option would be to use the stock exhaust manifold with a straight pipe, presilencer, and freeflow exhaust. Do you think that the performance of a dual pipe would be worth the extra weight over a header to straight pipe combo? The flow numbers should be better and more predictable with a well matched/setup dual pipe in theory but the added powere would be hindered by the extra 5 feet of piping and muffler.

As for the port matching of the intake manifold I've found plenty of details in searching on that as well as porting in general. However, I've heard mention of throttle body modification; what does this entail and is it beneficial on an n/a build.

Lastly, please don't flame this lol I can already see it. I've been think of building a cheap sort of air ram sytem to route fresh air from outside of the engine bay directly to the engine. I know... if it was some magical system everyone would have one but is there actually any proof to whether it does or doesn't have any effect?

Troclo

I had a streetported FC n/a 1988 the produced 200 hp but the exhaust was so loud that the car was almost undriveble! It also had a lightened flywheel which resulted in the clutch going out several times as torque is an issue on n/a 13B's. Go on a diet and strip the car swell!

Pettersen

iTrader: (1)

It's hard to prove, since the hp increase won't show on a dyno run.

When the car is moving it does two things:
1: it supplys the engine with cold air
2: It increases pressure in the intake if done properly


Speedhunters featured an N/A car from Top Secret, and it had a properly buildt intake wich at high speeds actually created positive pressure in the intake manifold.


CAR FEATURE>> TOP SECRET VQ32 SKYLINE GT-R - Speedhunters

diabolical1

iTrader: (3)

well, i can't say how much it would cost you, but i think i remember Yaw building one for a Gen II race car many years ago. there were photos on his site, but i haven't been on there recently. if they're still there, it may give you some ideas. however take heed to what Pettersen said. wouldbe hard to "prove" (or rather quantify) effectiveness.

j9fd3s

iTrader: (3)

you're over thinking it. the S5 rotors vary compression by .03, its close enough. the weight difference between a single or dual system is probably under 5lbs, which isn't enough to matter.

besides length, the only improvement you're making on the RB header is the bend out of the engine. so either make it modular so you can make changes, or pick something simple, and it'll be good enough that something else will be the restriction.

the throttle body is already plenty big, you should make sure the double throttle plates open, or just remove em, and then really you're done. you can polish it, but its not the restriction, so its not doing much.

the ram air will work, its just not simple in the FC chassis

jorx7

iTrader: (11)

anything is possible but it will cost money. look up my name for my build thread. I'm at 220=230 and it cost about 6 grand for the motor and edu plus running. add 1,500 on top of that for defined auto custom exhaust. so it is possible but will cost you!

jorx7

iTrader: (11)

and i still need a paint job! lol

Tanj!

iTrader: (5)

Last I checked paint doesn't make you go faster. Unless your playing Grand Turismo and then you better be washing that car.