Intake Question - Removing the hump

[FWD turbo]

I was thinking about pulling my intake and removing the infamous EGR "hump" in the middle. My question is for the guys that have already done this. How much of a benefit did you get from this? Also, did you notice any difference in the amount of boost you were making? Does removing that restiction in the intake make the boost go up, down, or have no effect? I'm guess I am just wondering if you guys saw enough benefit to make it worth pulling the intake and spending the $30 for the gasket just to do this. What do you guys that have done this think?
Thanks for your input.

 

[TurboRegal84]

I would not totally remove the hump. The 'hump' as they call it is kind of flat on the top. What I did when I had my 84' was take the 'hump' and make it into a point. This will split the air flow coming down from the Turbo and provide a steady air path for the incoming air.

I feel that if you remove that whole EGR 'Hump' the Air will not evenly divide. True the intake is a pressurized air box, but I feel gains are minimal when you compare romoving it all to just making it a point.

Hope this helps some!

 

[FWD turbo]

Thanks for your reply!
My buddy was looking at doing his and said the exact same thing you did. How much did you actually remove? Did you notice any real improvements? I am still trying to decide if I should pull the intake for the sole purpose of doing just this. I do have a rather large roller cam and front wheel drive heads with a little bit of bowl work. So I think they flow a little bit better than plain stock 8445's would. The intake is also port-matched to the heads. I'm just wondering how much power an untouched hump may be costing me. Wondering if I may get more of benefit from doing this than I would if my engine were bone stock. Any ideas?

 

[racemybuick]

this site is getting retarded. I tried posting the pics of what herb was talking about, but a page comes up telling me I cant, and to refer to a thread that already has the pics on it (avoid duplicating pics...what B.S.!) ....So..... Search for the thread "Intake Question" in the hot air forum, and you can see my intake pics, as I cannot post them here to make it easier for people.

If you dont wanna do the search, just go here:

http://www.t6p.com/forums/showthread.php?t=6063

I posted the pics freely there!

Enjoy!

John

 

[FWD turbo]

Thanks alot for the pics John. A road map always helps. Did you notice a real performance gain from that?

 

[racemybuick]

My car has not driven since the motor was pulled. I have had otehr financial woes that kinda superceeded the the GN, but I am sure Turboregal84 can answer that question!

John

 

[TurboRegal84]

To be honest I do not know on the gains...

I did several things at once! (Ported heads, Turbo, Intake, Different Chip, Exc)

Everything helps!

 

[Turbo Riviera]

I could be wrong here, but...

Taking the EGR hump down all the way would be like going from a dual plane carbureted manifold to a single plane. It will likely flow more.

For all intents and purposes, your engine only takes air in one cylinder at a time. For the moment we'll not get in to cam overlap. So theoretically why would we care if it divides evenly. The cylinder with the open valve is the "low pressure" area and the air will be drawn to that. The idea behind taking down the EGR hump is to increase the diameter of the passage to increase air flow. And let's face it, the hot air manifold's passage between the turbo and the intake's plenum leaves alot to be desired. Once in the plenum however, it's a decent manifold.

Just thinking out loud...

 

[Jerryl]

Refreshing!

 

[FWD turbo]

Very Interesting train of thought, Mr. Turbo Riviera. Perhaps someone that removed the whole hump from their manifold could chime in with their results?

I really appreciate all of the input you guys are giving me on this.
Thank you!

 

[racemybuick]

Originally posted by Turbo Riviera
I could be wrong here, but...

Taking the EGR hump down all the way would be like going from a dual plane carbureted manifold to a single plane. It will likely flow more.

For all intents and purposes, your engine only takes air in one cylinder at a time. For the moment we'll not get in to cam overlap. So theoretically why would we care if it divides evenly. The cylinder with the open valve is the "low pressure" area and the air will be drawn to that. The idea behind taking down the EGR hump is to increase the diameter of the passage to increase air flow. And let's face it, the hot air manifold's passage between the turbo and the intake's plenum leaves alot to be desired. Once in the plenum however, it's a decent manifold.

Just thinking out loud...

I wish I could answer this! I am not sure about flow numbers, but I will pose this question my my machinist and get his input. Very good point!

John

 

[FWD turbo]

I have decided that I am going to port my manifold. I am planning on pulling it off next week, so I still have some time to decide exactly what to do with it. I am also going to have the EGR port welded shut, since right now I just have a block-off plate.

Also, if I can sell my winter beater, I will be shipping my stock turbo to Limit for some "improvements."

 

[FWD turbo]

A little update

For those of you that are curious, here is what I ended up doing.

I removed the top and sides of the EGR passage down to where the straight sides start to curve. The actual EGR passage is very large. Removing the top and sides of the passage left a "trench" in the bottom about 1/4" deep and about a 1/2" wide. I then took the manifold to a really good welder that I know. He filled in the trench and gave me a "peak" in the middle. I then went back in with the tool, removed more material and gave it a nice sharp point. This seemed to me like the best of both worlds. The Hump itself, and its square sides and top are completely gone. Yet there is still a nice curve at the bottom to roll the air, so it is not hitting a flat surface at the bottom and creating any turbulence. This really opened it up inside and I think it will flow alot more air than before. There is a huge difference in the amount of open area now. I hope my explanation makes sense to you guys, I don't have any place to host a pic or would show you what I am talking about.

 

[afresh]

What else did you do to the intake? Got any pics of what you have done?

I have an intake sitting at home waiting for porting. I'm just trying to decide what is going to be the best way to proceed.


Andrew

 

[Turbo Riviera]

Hey andy,

change your sig to show the new time!

He'll need someone to host the pics... I'm sure you know someone who can do that.

 

[afresh]

FWD Turbo,

I didn't even notice you said you don't have anywhere to host them. Email them to me, and I can put them up on a site.

Scott,

Signature updated!

 

[racemybuick]

why do you need to host them? Just post the pic on here!!! downlaod it to your comp and there is an "attach file" section just below the text box when you reply to every post....find the pic you want, select it and post it!!!!

I cant wait to see it....I am sure it looks good!

John

 

[Jerryl]

Anyone know?

What is the real restriction in the intake after you "remove or chamfer" the hump?
Runners leading to the plenum, or ports, or ........... ?

Hot Air Intake Cross section (Text added for future searches)

 

[ShaunKris]

Frik.. I wish there was a bloody back up for pictures..

 

[ShaunKris]

Well.. this is an old thread. I'm going to attempt removing the hump. I have shitty tools, but I'm going to try anyway. I'll post pictures of what I'm using, and how I'm progressing along the way. Please ALL you experienced hotair guys help me. All you other guys if you don't have experience (no offence) please just observe until I'm completed. Then you can have at er' and tell me what you would've done lol.. thanks in advance. I HAVE NEVER DONE ANY PORTING EVER. This is a first for me. Here we go, one day at a time.