Welcome to www.JeepStrokers.com!!
Not yet a registered user? You are required to Register before you can post within this topic.

Intake manifold and header project

Performance mods and Advanced Stroker discussion.
Post Reply
BcurpKodiak
Making Progress
Making Progress
Posts: 77
Joined: November 2nd, 2015, 8:12 pm
Vehicle Year: 1997
Vehicle Make: Jeep
Vehicle Model: XJ

Intake manifold and header project

Post by BcurpKodiak » May 17th, 2018, 4:46 pm

My stroker is going in soon. It's hanging from the hoist, just finishing a few last things.

Once the summer is over and I'm done fishing I plan to start a custom intake manifold and header to pick up a little more power. The cylinder head I'm running is the eddy head ported by Russ showcased in these 2 threads https://www.naxja.org/forum/showthread.php?t=1120948
viewtopic.php?t=4899

That thing flows better than some aftermarket SBC heads. Here's the solid cam I'm running from Lunati (they made it just for little ol' me)
Image

We're all very familiar with the older "log style" intake. I want to cut off the "plenum" about where the red line is. It should to me, run a lot like a single plane intake and that's what I'm shooting for
Image

I've done a lot of reading about custom sheet metal intakes. It seems that you want a plenum with the same volume as your engine's displacement. Mine is about 284 CI. It would be fairly easy for me to cut this intake apart, build a square/rectangular plenum that is 284 ish CI and weld it to it. I would cut the TB mount from the old intake and weld it to the new manifold plenum (and port it out to 70mm). Plan is to port the crap out of the runners where they meet the plenum and attempt to make them like velocity stacks. The cylinder head side of the runners/ports would be ported in the same way Russ port matches them.

I would then like to build or have built a custom header with 1.75" primaries based off data from this article http://www.superchevy.com/how-to/148-04 ... -shootout/

I compare my stroker to a SBC 383 a lot. Each engine has a displacement of about 47 CI. The 383 in that article has 440 hp, which if broken down per cyl is 55 hp per cylinder X 6 = 330 hp (to compare to a Jeep I6 stroker). This is why I believe 1.75" primaries will work well for me. I hope to possibly make 380 HP at least with a custom intake and header.

The high flowing head, big cam, big intake and header should work well together and work in about the same RPM range hopefully. I'm running 33's and 5.13's. At the same time I do this I might change to 5.38's as well. I have a 2800 stall converter

So, what do you guys think??

User avatar
SkylinesSuck
Donator
Donator
Posts: 442
Joined: February 14th, 2009, 11:11 pm
Stroker Displacement: 4.6L
Vehicle Year: 1998
Vehicle Make: Jeep
Vehicle Model: Wrangler
Location: Northern VA

Re: Intake manifold and header project

Post by SkylinesSuck » May 17th, 2018, 7:39 pm

Very interested to see how it turns out!

McSyd
Posts: 2
Joined: February 17th, 2019, 4:55 pm
Stroker Displacement: 4.6
Vehicle Year: 1985
Vehicle Make: Jeep
Vehicle Model: Cj7

Re: Intake manifold and header project

Post by McSyd » February 18th, 2019, 6:02 am

Any updates on this?

Cummins90
Making Progress
Making Progress
Posts: 54
Joined: May 14th, 2016, 10:29 am
Vehicle Year: 1996
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: Intake manifold and header project

Post by Cummins90 » February 19th, 2019, 4:40 am

McSyd wrote:
February 18th, 2019, 6:02 am
Any updates on this?
I wouldn't invest that much time in something that would produce so little, if any, gains. If you want a bigger plenum go with the late model intake. If you are doing it to mount a supercharger I would still discourage it because of the moderate power gains per dollar invested. A turbocharger is easier to fabricate a mount for and will provide gains up to and beyond what a stoker can achieve.

User avatar
The Beast
Learning to use the board
Learning to use the board
Posts: 35
Joined: October 12th, 2011, 2:00 pm
Stroker Displacement: 4.7
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Guelph ON Canada

Re: Intake manifold and header project

Post by The Beast » March 4th, 2019, 8:31 am

I actually did this and the gains are extremely noticeable especially the top end. Data logs show that you can actually run out of injector
and find that you'll start seeing a limit to a 70mm TB. I got a twin 58mm and I'm starting to max it. My 24lbs injectors go 100%duty at 90%
throttle. That shouldn't happen on a NA stroker but that's because the stock Int/Ex. manifolds are so F'ing pinched off it laughable.
That's why I didn't waste time with that stupid horseshoe intake and crap aftermarket headers and fabbed my own.
My Jeep is like having a conversation with two lions, in both my ears, inside my head, from the outside.... I hear good things from them!

User avatar
Cheromaniac
Senior Member
Senior Member
Posts: 2653
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Intake manifold and header project

Post by Cheromaniac » March 4th, 2019, 10:55 pm

BcurpKodiak wrote:
May 17th, 2018, 4:46 pm
My stroker is going in soon. It's hanging from the hoist, just finishing a few last things.

Once the summer is over and I'm done fishing I plan to start a custom intake manifold and header to pick up a little more power. The cylinder head I'm running is the eddy head ported by Russ showcased in these 2 threads https://www.naxja.org/forum/showthread.php?t=1120948
viewtopic.php?t=4899

That thing flows better than some aftermarket SBC heads. Here's the solid cam I'm running from Lunati (they made it just for little ol' me)
Image

We're all very familiar with the older "log style" intake. I want to cut off the "plenum" about where the red line is. It should to me, run a lot like a single plane intake and that's what I'm shooting for
Image

I've done a lot of reading about custom sheet metal intakes. It seems that you want a plenum with the same volume as your engine's displacement. Mine is about 284 CI. It would be fairly easy for me to cut this intake apart, build a square/rectangular plenum that is 284 ish CI and weld it to it. I would cut the TB mount from the old intake and weld it to the new manifold plenum (and port it out to 70mm). Plan is to port the crap out of the runners where they meet the plenum and attempt to make them like velocity stacks. The cylinder head side of the runners/ports would be ported in the same way Russ port matches them.

I would then like to build or have built a custom header with 1.75" primaries based off data from this article http://www.superchevy.com/how-to/148-04 ... -shootout/

I compare my stroker to a SBC 383 a lot. Each engine has a displacement of about 47 CI. The 383 in that article has 440 hp, which if broken down per cyl is 55 hp per cylinder X 6 = 330 hp (to compare to a Jeep I6 stroker). This is why I believe 1.75" primaries will work well for me. I hope to possibly make 380 HP at least with a custom intake and header.

The high flowing head, big cam, big intake and header should work well together and work in about the same RPM range hopefully. I'm running 33's and 5.13's. At the same time I do this I might change to 5.38's as well. I have a 2800 stall converter

So, what do you guys think??
I'm also interested to see how this project turns out. I like the ideas going into it.
When building a larger plenum for the intake manifold, keep in mind that you'll need to clear the brake booster and leave enough clearance for the hood with the throttle body mounted and the airpipe attached (unless you mount the TB sideways on the driver's side and modify the linkage).
1992 XJ 4.6 Stroker - 5MT - 202rwhp/258rwtq - Sold 13/12/2016 :cry:
Stroker build-up, Stroker "recipes"
2006 Mustang 4.6 GT - 5MT
- 311rwhp/328rwtq - Midlife crisis car :D
Basic bolt-ons

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests