meanEG

i have a nicely built turbo project coming down home stretch, and i was thinking of purchasing a obx or sk2 manifold.

i have removed the butterflies, and cut the runners down to as short as possible. the manifold looks pretty effective, but i did a search and found no results of proven power. any insight.

josh

meanEG

no one knows?

meanEG

...

bubbahatch92

I removed mine when I did my build. Can't really tell you if i gained power or not because my whole setup changed, but it doesn't seem to have hurt the car any. I removed the butterflies and opened up the center piece to increase plenium volume, and shorten the runners.

Darkness

RudeLude

what would shortening the runner do as opposed to leaving them the original length and porting them out?

meanEG

short runner usually means more hp. esp under pressure. shortened the runners by removing the butterflies and cutting out the dividers in the bottom half of the manifold. basicly making the plenum twice as thick.
i am glad to see i am not the onlyone that has tried it.

DxTrix

Anyone have any results on this?

TGrant

Short runners will give you high end horsepower but, you will sacrafice low end torque. Long runners will give you low end torque but, you will sacrafice high end power.

meanEG

does this really matter on a turbo application?

RudeLude

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by meanEG &raquo;</TD></TR><TR><TD CLASS="quote">does this really matter on a turbo application?</TD></TR></TABLE>

happyb16xrc

does anyone have any pics of this being done. the butterflys are the carb looking things inside the manifold?

b16hybridsol

This is something i've been playing around with in my head because of my build and i think it will work out very well. Anyone remember erik aguliar's gsr coupe went 9's with a stock casted manifold (obviously internally modified). The gsrs use a similar internal setup to ours and although erik's car was NA i think that there is a lot of power to be found in modifing the stock manifold because of the restrictive multiple ports, like making them into just one massive plenum

meanEG

exactly

Specail Ed

I asked this same question a few months back. One of the NA guys posted dyno results, I searched but can't find it. He did loose some bottom end torque, but gained top end HP. I currently have mine completely gutted. I can tell I lost a little torque, but it pulls really hard top end. I'm waiting from my manifold to show up, then I'll give you some results after it's turbo'd.

TGrant

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RudeLude &raquo;</TD></TR><TR><TD CLASS="quote">does this really matter on a turbo application</TD></TR></TABLE>

Yes

meanEG

so i am going to lose torque at low before spool up or whole rpm band? a turbo wil produce enough torque as it is so losing abroad, if so, hopefully wont matter if i gain more hp.

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TGrant &raquo;</TD></TR><TR><TD CLASS="quote">

Yes</TD></TR></TABLE>

how do you figure. Turbos already sacrafice some bottom end torque unless you size it not to... but the majority of the time a turbo that maintains/multiplys bottom end torque is not going to keep pulling through the upper rpm range.

I barely noticed a difference when i took my butterflys out and everyone jocks on those about low range torque loss. And the rpm range you lose that very slight amount in, you don't need anyways.

Whens the last time you drove a car and said man i wish this car had 9 more ft lbs from 1500 till 3k? because its not goign to be a very drastic loss at all

plus while racing, you are never going to get that low in the rpms

happyb16xrc

is there any pics of any of this?

meanEG

yea rea my mind, i just wanna see some dyno time

TGrant

Chad have you had High Po fuels yet? You will see what manifold runner lengths do on the dyno.

b16hybridsol

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TGrant &raquo;</TD></TR><TR><TD CLASS="quote">Chad have you had High Po fuels yet? You will see what manifold runner lengths do on the dyno. </TD></TR></TABLE>

nah, haven't had the class yet. From what I understand you basically move your power band around with runner lengths (right to left, left to right).

I know that prostock car teams specifically make 1/8 to 1/4" changes in runner lengths to move their power bands around 100ish rpms give or take.

I'm pretty sure these guys aren't talking about modifying the lengths very drastically maybe choping an inch off.

Plus you have to remember we are talking about an h-series here. They have down low torque and it is a very very rediculous difference to a b or d series. I don't know the exact number difference but you need to drive an h-series car to understand what i'm talking about. The power/throttle responce is always there and very strong. In my integra you can stab the gas in any gear and it will pick up and go, and i'm talking pre spool up. But nine times out of 10 in my delsol if i need power i need to drop to a different gear.

Point of all of that is that yes it will affect power no doubt, but to 95% of the people that turbocharge their cars for more power are not going to be dissapointed by this minimal loss for a more ultimate gain, where the power can be of better use

meanEG

that is axactly wjat i wanted to hear. i nned to dyno back to back. thats hard to find.