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Opel Key Master
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5,288 Posts
If this is coming up in the near, and I do mean near future, I will take one as well. If not, I would have to get the car done and have it mocked up down the road, which I do not want to do. I have a flange like I had made for Gordon, but don't have to use it
 

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Super Moderator
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13,933 Posts
Keith, I will have it two ways for a GT with a 2.4 exhaust manifold:

1.75" secondary tubes into 2.25" main tube

2" secondary tubes into 2.5" main tube

It depends on the level of prep of the rest of the engine.
Hope to get my parts next week, then I need to dig out a GT and put it on the lift. Maybe 3-4 weeks until the prototype and jig are built?
 

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Just Some Dude in Jersey
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15,454 Posts
Discussion Starter · #23 ·
I'm in no hurry, so if Keith needs the size that you're making for me, it's fine by me if you send it to him to expedite the job he's on. I really can't see myself getting to my 2.4 project until Winter.
 

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Opeler
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474 Posts
I need some help here regarding this thread. Has any one out there put a 2.25 or 2.50'' exhaust on a GT? I did on mine and it was alot louder than my radio. Has anyone done this? I need mental help.
 

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Just Some Dude in Jersey
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15,454 Posts
Discussion Starter · #26 ·
put a 2.25 or 2.50'' exhaust on a GT? I did on mine and it was alot louder than my radio.
Is there a problem here? Isn't that the whole point? There's no sense in having a fast powerful car if it doesn't sound fast and powerful.


Sounds like mission accomplished to me!


:yup:
 

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Part of the deal with Gordon was I would build his headpipe custom, but would use it as a template in order to build a jig fixture so more could be built down the road.

I contracted to have a bunch of 3/8" thick steel flanges water-jet cut for future head pipe builds, and just got them last week.

Note the difference between the 1.9 flange size with 1.625" tubes, and the 2.4 flange with 2" tubes!

I ordered the tubing bends last week so pretty soon we'll have some of these built up.
Hey Bob, do you still have any of these?

I just found 8 new 52mm sprint type manifolds in my lower storage area.
 

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Super Moderator
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Hey Bob, do you still have any of these?

I just found 8 new 52mm sprint type manifolds in my lower storage area.
Juan, I have the 2.4 headpipe flanges. But they are not the same as the Euro 2.0 liter 'sprint' flange. They are larger still.
 

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GT Owner
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394 Posts
I'm going to be fabricating a custom headpipe to fit a 2.4 CIH exhaust manifold to a GT. The prototype will be a 2.25" main tube diameter, but I will be building a jig that enables me to make them in either 2.25" or 2.5". I'll be posting up pics here when the prototype is done then I'll be listing them in the ad forums, on a one-off build basis.
Did this project get done ? If so ; can I purchase one ? 😎
 

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Did this project get done ? If so ; can I purchase one ? 😎
I did build a bunch of them. All the headpipes got sold except for one, and that one was going to be part of a full system from headpipe to rear muffler. I didn’t build the front muffler/over-axle section before closing my old shop though.
 

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Just Some Dude in Jersey
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15,454 Posts
Discussion Starter · #33 ·
This is the headpipe Bob made for me. My manifold was used and cracked(The 2.4 manifolds are supposedly prone to cracking), so he welded up the crack and had the headpipe and manifold jet coated. 2.25" system for my stock cammed 2.4/2.5 engine. I had a muffler shop make the rest in stainless. Flowmaster muff and really excellent tips.

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Opeler
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1,298 Posts
So, with talk about head pipes, what’s the trade off for a stock manifold with head pipe vs a shorty header with headpipe vs a header? This thread was geared for torque producing headpipe, and most of us on here are street driving out cars and torque is where it’s at on the street or stoplight to stoplight.
 

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GT Owner
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394 Posts
I did build a bunch of them. All the headpipes got sold except for one, and that one was going to be part of a full system from headpipe to rear muffler. I didn’t build the front muffler/over-axle section before closing my old shop though.
If anyone bought one and now doesn’t need it ; I would be interested in purchasing it.😎
 

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Just Some Dude in Jersey
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Discussion Starter · #36 ·
For me, it was basically the issue of getting that difficult to make headpipe made and the inconvenience of getting my car to a muffler shop without anything attached to my manifold. The 2.4 manifold exit is actually cocked towards the engine, so the pipes have to be angled straight down when attached to the angled manifold flange. The 2.4 flanges were hard to get at the time. Bob basically came forward and said he had the flanges and would make a headpipe for me, using his Dad's GT to mock it up. Some other guys came forward who had the stock manifolds, but more jacked up engines, so he had the incentive to make a batch of a few in 2.25" for me and 2.5" for the jacked up guys. Almost nobody has the stock manifolds, they just don't come with the 2.4's we get from Europe. That's why I was drooling and darning when Cruiser offered up that one that you bought.

In my opinion, you're going to get the torque from your 2.4 engine regardless of your exhaust size. That part is inherent to the "over-square" stroker aspect of your engine and mine. Exhaust size comes into play at higher rpms, like most engine mods. But strokers make their best power at lower rpms than most engines and aren't regarded as high rev'ing engines. They're truck/SUV engines. If your whole thing is to drag race from red light to red light, in my opinion, any difference in torque due to your exhaust size, will be minimal at the relatively low rpms you'll be at.

Since I can't get another 2.4 manifold for my new project car, which will be getting my repaired 2.5 engine, I'm just going to get an OGTS shorty header, their 2" stainless headpipe, and then have my muffler shop make me a 2.25" exhaust system like my present car has for the rest of the way back. I've heard it said that a progressive expansion of the exhaust system in this fashion is pretty effective. Regardless, I have no other option anyway. I don't have a 2.4 manifold and Bob's not making stuff at the moment. I'll let you know if I notice any difference.

Bob and I have an arrangement to have him make me a wider front suspension for my present car when he does resume manufacturing operations. I need that front suspension asap, so that I can swap my present suspension over to my new car. Even if I could get a 2.4 manifold and then a Bob manifold, I need that suspension first. I can easily buy the Shorty and stainless headpipe right now and be done with it. If I notice that I've got less power, which I doubt I'll notice, then maybe I'll go for custom headers/2.4 manifold and a custom headpipe at a later date.
 

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Super Moderator
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My manifold was used and cracked (The 2.4 manifolds are supposedly prone to cracking), so he welded up the crack and had the headpipe and manifold jet coated.
I have had a bunch of the 2.4 manifolds that were cracked and that I threw away. Gordon’s wasn’t too bad, maybe only cracked 1/3rd as much as most of them. So I drilled out the ends of the cracks, beveled the crack, and silicon-bronze welded it.

I actually got a couple manifolds from Gil that were already cracked just for my headpipe mock-up work. He said he had had a pile of cracked ones.

They all seem to crack in the same place, FWIW.
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