You say higher compression than before, how much higher? 9.0:, 9.4:1, 9.7:1? If you were running only 14.0 psi, and hitting 315rwtq, that seems like good torque for the psi. However, your peak torque occurs very early, and falls off early too. Most streetport engines I've built/ seen hold peak torque to at least 6500 rpms. Who did the porting? Are you 100% sure its ported? The graph looks more like a stock port engine. Give us all the details of the setup, and maybe somebody will shed more light on the problem.

 

Mate can I just say thank you for post some proven technical date, congrats for sharing it with us.

 

Notice, Dyno Dynamics dyno...
They don't look like DynoJet graphs.
It's typically of a DD graph to look like that.


-Ted

 

Great side by side comparison. This should be stickied.

 

I'd also like to see a dyno test with the cosmo UIM/tb.
aren't they bigger than FD?

 

The FC manifold was a series 5

Not sure about the compression but i'm using series 5 rotors in this engine and i used series 4 in my old engine

The engine had done 500 miles after rebuild which i why i only went to 1 bar. I'm going to the Nurburg Ring in 2 weeks, when i get back it should have nearly 2000 miles i will swap the i/c and go back, i will let you know how i get on

FYI, i checked the pressure drop on my i/c and i had 3 - 4 psi more on the turbo side that at the plenum. too much>???????

The engine is most definately ported, i built it, i will attach some pictures of the ports.


Here is the i/c i use, XS power


Ported LIM which the old engine didnt have as the port runners were stock.



2ndaries



exhaust


the primaries are also huge with much bugger runners

 

would a bigger TB only make a difference if you hit the max on the current one, i mean i have seen over 500 bhp at the wheels on the stock FD LIM/UIM, TB and elbow, so if i only wanted 400 atw's the existing one should be ok, does it work like that?

 

i am using the school of thought that, larger runners (intake) means more air flow. more air means more power.

 

but what if your set up can already outflow another componant in your set up. For instance, if you took a completely stock set up, FD or FC, and ported and polished the throttle body as your only Modification, would you make any more power???

 

i think all areas of the motor must be considered. If you increase the exhaust, you should increase the intake. Otherwise your motor will choke on the intake and over heat on the exhaust.

Ideally, you'd do this all together, but that takes $$.

So increase your ports, get the motor together, then find a nice tubular exhaust mani w/ single turbo, eventually, go FD/Cosmo UIM (or even better, custom intake with ITB).

 

There is obviously more to it than bigger is better, but I am not really qualified to get into any complex engineering discussion where that is concerned.

However, usually longer intake manifold runners lend to better low end air flow, and shorter runners are better for top end. That is what I have learned in the past, and the dyno results seem to suggest that, since it seemed to improve your numbers in a lower rpm range.

 

how much more in total hp/tq do you think it will raise with a FD LIM,TB,IC elbow and counting the UIM too ???


because a friend of mine is doing me a setup with my S4 engine, with LIM,UIM,TB,IC elbow. (ill probably go with 4x720cc injectors too).

 

Archive material. Thanks for sharing! Now I can say my FD UIM isn't totally for looks if I ever get it installed.

 

the FD LIM isnt very good, its very small at the bottom to allow the twin turbo pack to fit. I would stick with the FC, its got much larger runners.

 

I wonder how much of a difference the spacer makes? Is it just for ease of installation of the FD uim or does it make even more torque by lengthening the runners?

 

Umm, there is a dyno graph on the 1st page that completely negates what you just said....

 

No, Antnicuk just changed the Upper Intake Manifolds (UIM) the FD Lower Intake Manifold (LIM) is cramped and uneven due to the low hood lines and twin turbos in narrow engine bay due to double wishbone suspension.

I am seeing over 20ft lbs of torque gained with the FD UIM and around 20hp gains as well. The big torque then hp gains are over a good spread as well from 4,500rpm to 6,500rpm and there was a "little" ~9hp max bump from 3,800 to 4,500rpm.

There is only a few hp LOSS in power with the FD UIM in 3 sections from the beginning of the pull to 3,500rpm.

Am I the only one reading the chart wrong or the only one that thinks more than 20hp/ torque is a bit much to expect from swapping just STOCK upper intake manifolds?

 

timely resurrection

re-evaluate the data

 

I've been revisiting this issue (made a thread in the single turbo forum).

What I'm most concerned about in this dyno sheet in terms of how "scientific" it may be is that there is no log of rpm vs boost. Changing the UIM could have changed the boost curve without careful adjustment of the EBC. Maybe with the same boost control adjustments, boost peaked earlier with the FD UIM and then fell off, which could exaggerate changes in the powerband. And eyeballing an in-cabin boost gauge doesn't tell you much about the boost curve at a specific rpm, the analog ones usually have a damper to reduce oscillations and the digital ones read too slow.

Even a change of 1-1.5 psi in some part of the rpm range can make the whole "scientific back-to-back dyno run" premise murky. It's like when people say that an exhaust system on a T2 gives you 50-60whp but part of that change in power/powerband comes from a different boost curve.

Also, we know that relatively large plenums (s5 UIM, 13B-RE) are better for topend but not so much for mid range. Honda acknowledged this by designing a variable volume intake plenum for the NSX:

 

I believe the power difference between the FC and FD intakes definitely has to do with 1 or 2 psi more boost as you indicate, but it isn't from the turbo.

It is the pressure increase at the port at those rpms from the dynamic effect pressure waves that the FD UIM is designed to increase with its opposed facing 2ndary port runners and small plenum.

With the very quick spooling sequential turbos on the FD Mazda was free to redesign and shrink the plenum in an effort to maximize dynamic effect supercharging without sacrificing too much low end power.

This dynamic supercharging is more efficient than a turbo compressor so you gain more power per psi boost.

The S4 NA RX-7 made nearly 2psi boost at the port stock and required a plenum for low end power/driveability.

When I ran my set up with the S5 TII LIM and 3rd gen UIM naturally aspirated I originally had the MAP sensor line off of one of the nipples on the runners and data logs would show several psi at WOT from the dynamic effect waves.

When I put the turbo on I switched the MAP line to the plenum to help damp the boost fluctuations.

 

I would love to see more info and debate on this topic as i am considering this kind of setup on my car... seems like there is alot of theorizing but not alot of experience and dyno proof lol.. I hate when that happens

 

I too have seen this happen. I have seen spikes up too 3 psi, on my S4 N/A. I thought I was crazy!!!


Thank you

 

the debate will never end... to many variables.

But I noticed a huge difference when i swapped the FC UIM for the FD one. never compared it on the dyno. But i damn sure felt the difference.

 

As i see too many people did the fd uim swap...can somebody inform me the steps to do it?i know that you need,the fd uim,adapter,flanges etc.my question is what did you do with the oil filler neck?can i use one from fd?and what did you do with the tps?how did you connect the wires?is there any diagram?i'm going to use apexi power fc...thank you!

 

gia sou nikos, you also need an S5 lower intake manifold.

the power FC should be fine with the tps.