Tubular manifolds?

[RedZMonte]

So i was thinking about how i can make a little more power and maybe increase my spool up time on my turbo. I have 2 stock log manifolds on the car now connected to my turbo X-over. I was thinking about a few different designs. I looks like the stock manifolds are not very well flowing... Tell me what you think..

Design 1 (Custom Log - Kuntzie's manifolds):


Design 2 (Custom shorty Tubular style):


I know the tubular will flow better... My thoughts are will it flow enough to make it worth while building over a log style.. and tipically the log is a little sturdier, so i think the log will have less potential problems..

S

[timg]

I like design 2. To me, design 1 isn't really worth the extra hassle over stock manifolds. What I would love to see is design 2 going into a divided turbine housing.

Tim

[RedZMonte]

What I would love to see is design 2 going into a divided turbine housing.

Tim

HAHA great minds think alike .. Turbonetics builds a Divided (twin Scroll) housing for our turbos iirc that was an option when we ordered them wasnt it?

i think im gunna get some flanges made and start accumulation the parts for the new manifold/x-over setup. once i get it all done then eventually order a new divided housing for my turbo.. It should drasticly help spool up.

Do you think it a shorty style tubular manifold would make power on a NA motor? if i can build it right i will try to make it fit in stock locations. that front mani is pretty narrow at points, ZZP makes a different style one for the 3800's that makes power because the stocker is so restrictive it looks like this, but i like the full tubular one better...:



this is more what im thinking, but only more compact..



S

[loner666]

Mine before being wrapped



Flows quite well it seems and the car spools like a bat out of hell with a .63 AR exhaust housing

[RedZMonte]

here is one i like.. Looks simple and looks like it will flow well also..


S

[RedZMonte]

i like this collector 3-into-1 and it uses a V-band flange

[grandprixgtp_91]

If im not mistaken, doesnt zzp recomend log style manifolds over tubular? i think they say it lowers KR and is more compact, if thats the case, wouldnt you be better off with stock manifolds? i think they only recomend that with boosted applications. But if u want a faster spool couldnt you just uprage your turbo? ceramic ball bearing with a smaller exhast housing?

Im not sure, just some things i thought.

Jake

[RedZMonte]

Log manifolds are stronger but don't flow as well as tubular... Same consept as Headers on a NA car, need to make them flow more efficently..

The stock log manifolds are pretty narrow inside, they have to be pretty restrictive.. I could upgrade the turbo but if i have restriction before the turbo it would only help so much... My turbo should spool a bit faster with just a new exhaust setup and a Twin scroll housing... I shouldnt need to upgrade the turbo to get the results im looking for.

S

[jmgtp]

Shane,

I took some pics of the front manifold like I said I would.... then I also managed to leave the camera at the garage! My bad, I should be back there tomorrow and will pick it up.

From what I remember you are correct, the stock logs have 'narrowings' on the inside that aren't so visible from the ouside.

It seems like they don't have any length of pipe to blend the exhaust into the the log but rather just dump it right against the backwall - can't flow that great. Some newer cars have manifolds that look almost like a 3 to 1 header, seems like that would at least be an improvement.

[IsaacHayes]

Yes if you are going to a "log" style manifold, it's best to at least angle the ports at the direction of flow towards the main log, instead of a 90* angle where it hits the side of the log. You can still have a compact log style with short "runners" that angle and direct the flow in the right direction.

[RedZMonte]

If im not mistaken, doesnt zzp recomend log style manifolds over tubular?

Jake

Here is the inside of the DOHC log manifold. (thanks jmgtp)... Not very flowy..


I would think a tubular manifold will have a higher velocity of exhaust gas... faster spool up and more efficent in high RPM.... (Like a header).. correct me if im wrong.

[timg]

Tubular is definitely worth it from a power standpoint.

http://www.full-race.com/articles/Bseriestest_writeup.pdf

http://www.full-race.com/articles/1.8T_turbo_manifold_test_writeup.pdf

Tim

[z284pwr]

I didn't see it mentioned, the issue Kuntzie has, along with the TGP guy is the dog bones are on both sides of the car, so making a front header is basically impossible with the big dog bone mount on the passenger side of the car.

http://www.edwardsracing.net/off_topic/turbo2.JPG

The log is right behind the mount so a quick 90 is the only thing that available

[RedZMonte]

there is sufficent room under the hood of the DOHC's to make the tubular style. the DOHC's only have the mount on the drivers side and its way up above the manifold.

S

[RedZMonte]

I didn't see it mentioned, the issue Kuntzie has, along with the TGP guy is the dog bones are on both sides of the car, so making a front header is basically impossible with the big dog bone mount on the passenger side of the car.

http://www.edwardsracing.net/off_topic/turbo2.JPG

The log is right behind the mount so a quick 90 is the only thing that available

I saw what your talking about.. it would have to be a tight bend like his existing manifold and then build off tubular from there... its just the 1 cylinder that would have to use a weld bend but still can make it tubular from there..

S