OK i have read all over this and other sites that swapping s4 and s5 manifolds shows an increase in power. However when I asked my engine builder what he thought of my plan to swap them he told me its all the same **** and i shouldnt waste my time. Has anyone ever dynoed an increase from this swap without porting playing a role? I know the vdi is a plus but then I see alot of people wiring it open so.... Just wondering if there is any documented proof of this gain? I am planning on porting the s5's and installing them anyway sinc ei cannot fidn a buyer for them. I usually dont let one persons word bother me without being backed up but these guys are known for both their work and their own cars so i trust them. i tried searching for a dyno without a port but couldnt find one.

 

Here's a dyno graph from Mazda's development of the VDI system, taken from the SAE paper on the S5. It shows the torque curve of the S4 13B compared to manifolds with different "communicating" lengths, which is the length the pressure pulses travel from port to port. The chosen lengths for the S5 manifold were "d" (400mm longer) when the VDI valve is closed at low rpm and "a" (200mm shorter) when the valve is opened high rpm. The two curves cross at 5200rpm, which is when the ECU opens the valve. The resulting torque curve is higher than the S4's at nearly all points in the rev range.



Dunno if that's really what you were after, but I think it's pretty interesting. It certainly proves it works in stock form.

 

Theres a guy on here who has done the swap, it made a noticable difference in power. Mainly the manifold is excellent for low end torque becuase of the VDI.

 

complete s5 intake should improve things over complete s4 intake.

But if you go modifying things and discard the upper for something else, like a carb adapter or what not, don't be fooled the S4 and S5 LIM are essentially identical except for minor differences that do not affect performance but do affect engine compatibility (acv&cv exhaust port for example).

 

Back in my NA days I ran a hose from the VDI to the cab & attached the pressure side of a mity-vac.
Crusing in 3rd at 5500 I pumped open the VDI. - Wow a nice push.

 

Hey! Its not the same stuff, not even remotely! Has your engine biulder ever seen an S5 intake before? The shape is entirely different.

I've ported out and removed and installed tons of both manifolds and the S5 manifold is definitely nothing like the S4 manifold. It's a great mod for an N/A S4 to put on the S5 manifold.

From my reaserch, I cannot reccomend wiring the VDI open.

 

No that has been dyno proven over and over to be wrong.n The S4 LIM is considerably larger, and the S5 VDI sectioon must be port matched for the two to even work together.

I am sure what the guy means is that a complete S5 intake bolted onto a S4 engine is a waste of time, and there are only looses assoctiated with that swap.

However, a S5 intake on a S5 engine, or a S5 VDI and dynamic chamber bolted and port matched onto a S4 LIM and then onto a S4 block has been shown to produce increases with dyno testing.

See the S5 intake has smaller runners than the S4 versions leading to increased intake volocity, at a loss of intake volumn. Using the hybrid S4 LIM and S5 VDI/UIM is a good compromise for the increased size of the S4 intake and intake volocity.

Also remember that the chart that NZ posted up the torque in in Nm, not foot/lbs. In ft/lbs the S5 engine at peak torque only make 4 more ft/lbs than a S4 engine peak torque.

 

The S4 and S5 LIM are practically IDENTICAL as far as the intake ports go, the manifold inlet and outlet port configurations are identical, there are minor differences in the runners that actually lean towards S5 flowing better.

How much are you willing to bet?

 

it does make a difference. i have done it and dynoed. . the only thing is when i added the s5 upper i also added a header. but we all know that if you have a nice catback that a header doesn't do that much. i have a decent catback. i dynoed the car beofre these mods and came up with 126hp and 120lbs of torque. I then added the vdi and the header and came up with 135hp and 128 pounds of torque. I know that's weak. The engine has just got done being rebuilt by kevin landers. when he took it apart he said that i had a craked apex seal. . which is probably why i had such low power. but yea the engine will be back tomorrow all ported with s5 internals. should be fun. . lol In the end i would definetly recomend using the s5 upper intake manifold, mated to the s4 lower. you wont be disapointed.
Dom

 

Icemark has done considerable research in this area. I'm sure he'd be willing to take that bet....

 

http://www.pengaru.com/forums/index....wtopic=52&st=0

really?

 

i am with pengaru on this one, the lims are pretty much identical, the only diffrence being the actuation type for the 6 port sleeves

 

I'll take that bet. I have seen the dyno tests. I have done the dyno tests myself to back up what others have posted online.

Even the follow up to the infamous and often sighted Carls S4 to S5 intake swap, (http://homepage.mac.com/carldavis/intake.html) showed that when the swap has been done on a good condition S4 motor, using all S5 parts, that Torque was actually lower than using a S4 intake on a S4 motor.

You can claim that the S5 flows better all you want. I know better.

Now you post up that BS about the port size being identical. Anyone that has laid out a middle intake gasket, can easily see that the S5 center runners are considerably smaller as it enters the LIM (almost 3/16 inch dia smaller), and while the Aux ports are slightly larger EXITING the LIM into the block on the S5 design this actually is the opposite of what you want (remember again we are talking about this on a S4 block). The larger ports exiting the LIM, but near same size entering the LIM actually slows the intake velocity.

Now this would be a good thing at 7500 RPM.... but Gee the S4 engines are all designed to top out at around 6500.

Then you claim the port sizes are the same... heck your own picture of the two manifolds with rulers on them clearly shows that the S5 end plate runners are only 1 1/2 inches, not 1 5/8s. Next time try mm... it is much more accurate.

But the third thing that you miss entirely is what happens inside the runners (not just at each end).

Now, don't get me wrong... I am not in any way shape or form advocating the use of a S4 manifold on a S5 engine. I am simply saying that for each series based on the engine ports that LIM should be matched to the engine. And that using a entire S5 intake on a S4 block will result in lost HP and Torque, much like using an entire S4 manifold on a S5 block would.

And your linked post on carb runners has about as much input in this as using a Turbo manifold on a non turbo engine. I don't have any idea why you would think that a set up for a carb would have intake runners anything even close to what a multi injector and multi port fuel injected system would use.

But lets get back to the subject... If you still claim the entire S5 flows better, then put up dyno tests showing it. Same engine, use the entire S5 intake on one set of runs, and the S4 LIM and S5 VDI/UIM a second set of runs on any non turbo S4 motor and show the dyno tests.

 

I dont know why anyone would want those ugly manifolds anyways... From what Ive heard, the s5 manifold is good for stock ports, and the s4 is good for ported motors(s4). But I dont know how true that is.

So like I said before, just get rid of the Na stock manifold, its been proven how aftermarket and custom manifolds work better.(ie. ITBs)

 

he did not mean they look alike or anything so trivial, he meant that i would not see an imporvement that would warrant the time spent on it.

 

i thought was for better boost control and not power gain.

 

ah NICE POST! even bigger of a reason for me to keep the S4 LIM on my S4 block when i swap the stuff over to my s5!

 

Ok so as a final sum it all up questions"

WOuld it be advisable for me to do this and what would be the right way, port matching ect...?

Also I asked this in its own post and icemark made me feel like a tard cause I didnt know my own engine but im educated now and would like an answer. My engine consists of a s5 core with s4 front cover and s4 manifolds. WIll i need to do any fab work to make the s5 UIM fit, besides wiring the vdi to an rpm switch?

 

if you have a s5 core
s5 lim would botl right up

i have a s4 core... too bad we couldnt just trade cores... im putting a s4 bottom with s5 front cover, s4 uim, s5 everythign else :/

 

Ok, let me get this straight... I think Icemark is intelligent person and he knows what's he saying... So is it better have this setup (by the order of airflow):
* s4 throttle body
* s5 VDI system
* s5 UIM
* s4 LIM

Right? And what if i have S5 rotors installed in my s4? Will it make any difference?

 

Way to revive a post good buddy

Anyway I dunno about the TB but from the 10 times ive posted something like this, its only adviseable to use the s4 LIM on the s4 block, not the s5. I think the tb's flow the same and you just use the one made for your series car since they have different TPS's.

 

Yep, that's it exactly

 

Sorry to revive this thread again, but it covers what I'm looking for.

I just have a question on the subject. Someone in this thread had mentioned that the s4 intake works better on a ported motor and the s5 better with stock ports.

I have an s4 that has been street ported and was wondering if it would be worth it for me to put an s5 dynamic and UIM onto the s4 LIM. Port matched of course. I also have almost all the emisions equipment removed. Still have the air pump on there because I was going to use it to activate the 6 ports.

Thanks for any input.

 

air pump doesn't activate the aux ports on an s4 engine

 

You can use it to open them electronically. Like a pop-off valve for aux ports.