blue is for skunk 2, red is for stock GSR intake manifold. EDIT I WAS WRONG ABOUT THAT, sorry guys. its actually red for skunk and blue for GSR.

Im confused looking at this dyno graph.

-it appears w/ the skunk 2 piece that the turbo reached full boost and peaked torque at 5200rpms(232ft/lbs).
-With the GSR the turbo spools 300 RPMS slower and doesnt reach full boost and peak torque until 5800rpms(247ft/lbs).
-From 5k-6700 it appears that the GSR manifold is making more usable hp/torque
-From 6.7k-8k the two manifolds make the same power.

Has anyone noticed what Im getting at? I have a hard time believing that the GSR manifold will make 15lbs more peak torque then the skunk2 piece while the skunk2 piece makes no extra torque from 6.7k up.

I also have a hard time believing that c-speed would put up a dyno showing that the GSR manifold makes more usable power and then run/sell the skunk 2 piece.

this leads me to believe that on the skunk2 dyno the car was running less boost. This would explain why full boost is 300rpm's later and peak torque is 15ft/lbs higher. I dont think simply changing the intake manifold would cause a drastic change like that. It must be boost related. But If I am right, and the boost level was lowered, then the skunk2 piece really helps out top end tremendously.

C-speed indicated the GSR IM dyno was at 14psi, but he did not indicate whether both dyno's were at the same boost.


anyone else want to analyze the dyno with me???????

anyone else agree that the boost must have been lowered? or are these normal characteristics of the two manifolds. the car is running a custom kit w/ T04b turbo.

EDIT EVERYTHING I WROTE ABOVE WAS BACKWARDS! sorry people.


[Modified by DIRep972, 5:06 AM 9/11/2002]

 

c'mon guys. dyno plot analyzation is fun for the whole family!

errrr u think i read into things too much? anyone have direct experience with the skunk2 piece that can verify how the dyno should look. ??

 

Maybe skunk2 only makes good cam gears

 

well the a/f on the skunk plot is kinda off compared to the stock gsr plot. that could account for lesser hp

 

i'm confused too, makes you ponder why even change it out?

 

Two of the main things that I would say have already been mentioned, the cam timing and the air/fuel ratio. At the point that the GS-R manifold is achieveing its horsepower, it has the better a/f ratio, and the same goes for the skunk2 manifold. The amount of air induced does noting for the motor if the a/f ratio cannot be achieved. Also, the changes in airflow from manifold to manifold, espicically on a boosted Honda based on what ECU program? That could be a deciding factor in this. The fuel system, size and flow comes into question here as well. Then there is that dyno I saw in some Turbo magazine I got stuffed away at my dads house, where a near stock Si lost power with the ITR manifold, but gained 7 peak horsepower once the cam timing was changes, but I can't remember what the cam timing was changed to. Runner length versus velocity, blah blah blah.

Chris, call me, I have one of the craziest stories to tell you, actually, Big Ron has the story to tell, pert f'in crazed action happened tonight.

 

good point. i wanna hear what other people have to say on this too. BTW has anyone noticed what i/m is on the 10 second ericks racing car?

 

Ok. to avoid further confusion.. the RED graph is the SK2 manifold. It had noticibly power in the midrange even before tuning.

PS: boost levels were the same.


[Modified by G3-TEG, 1:09 AM 9/10/2002]

 

But that looks like the skunk2 manifold only made more power from 5300-6500? anybody have a dyno on how the JE manifold compares to these 2?

 

oh man. now I am really confused!

but thanks for clearing that up cresent!

do u have any insight to to why no peak hp was made with the skunk piece?

 

the turbo he was running, if I remember correctly, simply couldnt breath that well up high.

 

wow you lost 15 torque! ouch.

 

See this is exactly why I still run with my stock GSR IM. There is so much confusion and to many arguments about IM's that I can't make sense of it all.

I will say this though..most of the people that I know that were running the Sk2 IM are now all switching over to the JG Victor X.

Concerning the dyno charts...I would assume that both runs were charted on a dyno with a wideband O2 sensor...right?....if not then I bet that is the problem...A/F ratio may have been all screwed up.

 

All dynos that graph AFR are wideband.

 

Ran 155.92 mph in qtr mile with stock gsr mani (at 24 lbs boost). It has to be doing something right. In my brilliant wisdom, I am switching to the JG but not gonna give away the gsr just yet. BTW, we did remove the secondary butterflys.

 

man thats why ive been stockpiling GSR manifolds lately, i am so set upon the idea of machining out the butterflies... think about it, a HUGE plenum and those runners that change shape and are essentially giant velocity stacks... hmmm i need a cnc

 

Theoretical rant after a few :

The GSR manifold has some pretty good flowrate, but it's got SO much surface area. You are going to be experiencing major drag on any column of air you accelerate down TWO runners at the same time. That said, it looks like you get some nifty vortices where the two runners meet. Looks like flow mixing will be prime right here. Just right for the injector to blow its load and let the sweet atomization carry it's seed right into the cylinder.

The Skunk manifold seems to be more suited for a NA engine due to its more willingness to create a favorable harmonic resonance at various RPM(2 runners of different lengths muddles this effect). Flowrate is good for a single runner manifold, but not as good as dual runners.

Turbo engines are mainly dictated by the characteristics of the hairdrier hanging off of its exhaust manifold(as you can see by the falling off torque up top). Basically, you want to let that **** breathe the best it can, then let its efficiency curve dictate your powerband. The GSR manifold with alot of flowrate wins here. Also, boring out the plenum of the GSR manifold might yield some impressive benefits.

BTW, working in an Aeronautics research facility by day makes you a damn geek.


[Modified by Def, 8:27 PM 9/10/2002]

 

all i know is i like my modded gsr intake on my prepped ls head. obviously made more power than a stock b16 head and type r manifold. i did the vtec conversion then converted it right back to how i had it. people always ask me why the f'ck did i put the gsr intake manifold on? anyway...

 

so should i put my gsr intake maniflod back on. i still got my engine out cause im waitin on my lsd. I pan to just ge all the bolt ons and maybe in a year or two boost it. so what im askin is if the skunk 2 is a better manifold to have. I want the better of the 2 i can prolly exchange it for cam gears and some misc. stuff. please let me know what u would do. thanks

 

damn my bad. I think this post got screwed up. Because in the original post I stated that the blue is for skunk and red is for GSR but that was wrong. C-speed, the guy who made this dyno, verified that it was the opposite. which would change the integrity of the whole post. U need to reverse things now. and SKUNK IS RED! GSR IS BLUE! sorry guys.

 

Well that would probably make more sense with those charts. Would probably mean that a JG Edelbrock manifold, with turbo, would improve over both those graphs. Nothing is for certain until it goes on the dyno. But you have to hand it to Honda, their 10 year old technology really holds up.

 

I bet there is alot of car companies that wish people said that about them.

 

I see your points, sort of, although they arent really based on much solid info even if you work at an aeronautics research facility by day. i dont think you read my post correctly. Also i dont see how a horizontal plane can cause swirl? Its just a sort of 2 plane merge collector. You are obviously somewhat familiar with a standard GSR manifold, but not the modified ones like the erick's racing unit that joe alaniz built.

I am talking about machining out the plenum, the runners, the mating surface, everything. Then look at the manifold, its just a huge plenum with giant velocity stacks for ports.

so why are dual runners good for flow numbers, and why does a GSR manifold have better flow rate? Mass flow rate of air should not be affected by the number of runners...

are you an ME or AERO-E??

 

I got a feeling the going rate for GS-R IM is going from 50 shipped to 200 shipped very shortly......

thanks chris
hehehhee

I tell you what, when I get back, we'll do the comparison, we'll dyno my car with the skunk 2 then switch it back to the GS-R IM without the secondary...


we'll settle it then....

stan

 

I have a lot of gsr IM. Maybe I should play with them more..