BLOODYKNUCKLESRACING

Im working on rebuilding an N/A S5 engine but i got this scrap S4 kicking around and looking at the intake manifold the S4 looks like it has better flow but im hearing some conflicting arguments either way. so im hoping i can put this to rest soon which is better any thoughts?
S5
bridge ported N/A
tubular header w/ 2.5" exhaust

Shainiac

iTrader: (7)

The stock manifolds on a bridgeport? The stock manifolds are not suited for bridge ported motors. Not only will the stock ports not flow enough for a bridge, the runners are too long considering you will be making peak power much higher. Also, are you running the stock ECU? The stocker too is not designed to run a motor so heavily ported. Your best bet is some sort of custom manifold and a stand alone.

MazdaMike02

iTrader: (4)

S5 intake is better...why do you think s5 cars had a significant gain in HP...the intake was one that contributed to that.

Jager

iTrader: (10)

What about exhaust, compression bumper, and everything else? The S5 intake didn't do that much.

farberio

iTrader: (7)

S5 intake on an S4 car will give 12 whp boost. It does quite a bit, mainly due to the VDI.

But for a bridgeport a custom intake manifold and ecu, as stated above, is needed.

Delicious

Do you need an S5 ECU to run the TB on an S4?

Delicious

....or anything else for that matter?

farberio

iTrader: (7)

An S5 ECU is completely rewired from an S4, so you can't use it at all on an S4 car.

Delicious

how hard would a conversion be and would it be worth it??

pengarufoo

The LIM is basically the same S4 vs S5, as far as the flow capabilities go.

UIM obviously differs quite a bit S4 vs S5, VDI present on the S5.

If you use a aftermarket UIM the S4 vs S5 LIM choice comes down to which is more convenient for you (is it a S5 or S4 block).

Also note that the major restriction in the LIM is the aux port actuator shaft guides and the shafts themself. Theres much improvement to be had modifying these.

farberio

iTrader: (7)

It depends, I am selling a kit to do it for $250 shipped. It takes about 30 work hours for one writeup to do it while keeping emissions.

If you know your way around cars, and its worth 12whp for $250 then its worth it. If you are just starting with cars I would probably not recommend it unless you are mechanically inclined.

BLOODYKNUCKLESRACING

thanks for the info guys i was thinking that the switch to the maf did most of the hp gains over the vam setup im running in my svo mustang. But about this bridge port problem is it that it just maxes out the maf as you hit high revs or what is it that holds up the ecu? i also have an N370 computer harness missing injectors boost sensor and maf will that work on an na if i get the rest of the setup? i was working on a pp engine for that setup for later. trying not to go standalone because i have an FD im running at 1 bar with a reprogrammed ecu id rather put a standalone in that one. that said could i run an n/a pp off of the turbo ecu as well and will that stand up to about 10psi with the N370 components if i just do that instead?
thanks for the input

Roen

iTrader: (2)

you need a standalone to properly realize the benefits from a bp/pp setup.

The AFM restricts you. The stock computer doesn't have accurate timing tables for that airflow. There's a lot of things wrong with the stock setup for bridgeports.

MazdaMike02

iTrader: (4)

Theres a write up on doing an s4 to s5 intake swap on here somewhere...i bookmarked it.

PS thanks for backing me up Farberio.

farberio

iTrader: (7)

No problem. In honesty though, the S4 LIM is 'supposed' to flow better then the S5 LIM. Though during my research of the swap I found that its negligible at best and not noticed on the but dyno.

rotarygod

iTrader: (1)

Whether or not the S5 manifold flows more than an S4 in a static test is irrelevant. There's more to power than just static flow. I've had things on the flowbench that boggled the mind but worked so only results matter. The results speak for themselves. The S5 manifold makes more power based on tuning benefits and not flow. When in "long" mode without VDI actuated, the runners are physically longer than the S4 manifold meaning it is tuned lower. With VDI actuated, although the air doesn't travel a physically shorter distance, due to the VDI valve providing a shorter distance for the return pressure pulses to travel back to the other side, the runners appear shorter to the engine which tunes the engine to a higher rpm than the S4 runners. The S5 manifold does increase power over an S5 manifold as a result. It's been proven many times. It's good for up to 15 hp more over stock or so. Maybe a little less, maybe a little more. Power also holds strong to a much higher rpm than the S4 manifold does too. It's a better manifold to use but only IF you are using a stock or streetported engine. A bridegported engine shouldn't be using either and it should only be using a standalone ecu or carb to control things.

NZConvertible

Actually the VDI system is almost entirely responsible for the S5's power increase. The exhaust was unchanged, the tiny increase in CR would give 1-2hp at the most, and the "everything else" you mention was virtually nothing else.

RX7freak08

What I was told about the S5 intake being better like NZConvertible stated was true. The VDI really gives you the 1-2hp more. The VDI is to eliminate the Back Pressure that comes up trough the intake. I was told. The S4 Doesn't do that. http://www.youtube.com/watch?v=-5mM-m23n40 This vid is a S4 intake on a half bridge. I know it doesn't help but you might see the results.

NZConvertible

No, it's responsible for most of the S5's 14hp peak gain, plus a broader spread of power through the whole rev range.

Completely wrong on several levels... How the VDI system works was explained only two post up.

Jager

iTrader: (10)

Ah, my misunderstanding.

I learn something new everyday .

RotaMan99

The VDI is explained in the FSM.

If the VDI only gave a gain of 1-2hp, then why did I and many others spend the countless hours swapping to the S5 intake and making it work?

From experience, 1-2hp is BS. You get a big push in the seat when the VDI kicks in. I say around 10-12HP. I havn't seen a back to back dyno yet though. I know its over 10hp gain.

fcer

ok ok ok.....so around how much gain would u get with s5 manifolds on a ns s4....and is it bolt on to the engine or do u need to do any conversions..?

fcer

sorry typo i ment n/a

farberio

iTrader: (7)

http://homepage.mac.com/carldavis/intake.html
I am selling most of the parts needed for $250.

Jager

iTrader: (10)

Alot of people on this site will do alot of work for little or no gains. Alot of skeptics here, including some misinformed people like myself .

And that's the slight issue, people also are big on "dyno" results, or some kinda track result. Having a butt dyno result from alot of people really won't make alot of people go bonkers over doing alot of work for someones seat of the pants experiences.

For example, on Cavaliers alot of people swap an intake from an older motor, everyone said it felt better then the old one. Some guy went and did before and after dynos and lost 14HP and 10TQ. It shows that the butt dyno is hard to beleive.