side by side header comparison
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
Very nice 
. The EM longtubes appear to have a 'd' shape port on the pipes. Are the LT4 heads 'D' shaped on the exhaust? ALso the angles look different on the collector looks like you'll have a little fun mating it up to your current exhaust. Im real curious to know how they fit in there. please keep us posted !!
. The EM longtubes appear to have a 'd' shape port on the pipes. Are the LT4 heads 'D' shaped on the exhaust? ALso the angles look different on the collector looks like you'll have a little fun mating it up to your current exhaust. Im real curious to know how they fit in there. please keep us posted !!
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
One thing i would like to add is about all the talk of 1 7/8s being too big. I notice on the LG (c5/6) headers they claim the most power. At the ends of their primaries they neck down a bit (the primaries merge into a 2 1/2 or 2 3/4 collector then it flares to a 3") to maintain velocity to help scavenging and low speed torque. No c4 header has ever had that setup like theirs. I wish they would make longtubes for us.
From looking at your headers Im picturing the exhaust flow in a 1 7/8th pipe will be a bit slower. Wether or not it will add power will depends on how much of a restriction if any the 1 3/4s were causing. Then the flow would dump into a 3" collector where it would slow even further.
My guess is you will lose low end torque but pick up in the high-mid and high end range of your powerband. Please get it dyno'd without any other changes and post your results !! This is great info and would put to rest alot of BS rumors about header size etc.
Last but not least it looks that the primaries are different lengths on the Ems. This might possibly mean they were measured and produced with the optimal lengths to provide the best scavenging effect possible. ??
From looking at your headers Im picturing the exhaust flow in a 1 7/8th pipe will be a bit slower. Wether or not it will add power will depends on how much of a restriction if any the 1 3/4s were causing. Then the flow would dump into a 3" collector where it would slow even further.
My guess is you will lose low end torque but pick up in the high-mid and high end range of your powerband. Please get it dyno'd without any other changes and post your results !! This is great info and would put to rest alot of BS rumors about header size etc.
Last but not least it looks that the primaries are different lengths on the Ems. This might possibly mean they were measured and produced with the optimal lengths to provide the best scavenging effect possible. ??
Last edited by 5abivt; Dec 23, 2006 at 02:52 PM.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
The LG C5 and C6 headers (except for their budget version) use merge collectors, which is the neck-down that you see. If you look at the 1-7/8 EM headers you'll also see merge collectors, this is to keep the exhaust gasses flowing as fast as possible to help woth scavenging. These headers are best matched to high-revving motors. They also have a version that are 1 3/4" stepped to 1 7/8" which also helps with low RPM flow.
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
You are making me so want to buy the EM headers. My TPIS LTs look nearly identical to yours even with the requisite "hole" in the outside of the #2 cylinder and the chafe marks on the inside of the same tube.
The EM look so much better than the old TPIS. I will await final word on install.
As an aside, did they offer 1 7/8" stepped to 2" as an option for the C4 chassis?
Aaron
The EM look so much better than the old TPIS. I will await final word on install.
As an aside, did they offer 1 7/8" stepped to 2" as an option for the C4 chassis?
Aaron
Melting Slicks
Joined: Oct 2001
Posts: 2,315
Likes: 110
From: Brandon Fl
My TPIS LTs look nearly identical to yours even with the requisite "hole" in the outside of the #2 cylinder and the chafe marks on the inside of the same tube.
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Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Do not get me wrong, I like my TPIS LTs, it is just that I would like to step up to a larger, nicer header if I were to go to the expense of another header install on my '87.
Aaron
Drifting
Joined: Oct 2006
Posts: 1,554
Likes: 13
From: Romeoville IL
Melting Slicks
Joined: Jul 1999
Posts: 2,875
Likes: 0
From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Racer
Joined: Mar 2005
Posts: 399
Likes: 2
From: Newtown PA
Seems like a lot of money and effort for a single digit rear-wheel horsepower gain. I assume that GS977 has other plans for the motor in that car (a great looking car BTW) which will benefit from that upgrade, e.g., 300+cfm intake ports, bigger cam, etc.
Thread Starter
Drifting
Joined: May 2005
Posts: 1,258
Likes: 38
From: springtown Texas
hey guys, i thought you might wanna see the TPIS collector. i posted a pic of the EM merge collector already, now look at this.
and also the diff in pipe size.
and also the diff in pipe size.
Last edited by GS977; Dec 24, 2006 at 08:00 PM.
Melting Slicks
Joined: Dec 1999
Posts: 2,816
Likes: 2
From: Austin, TX
Just to clarify for the guys thinking about the EM 1-3/4" headers. They don't have the merge collector like GS977's. His headers are a significant step up from their standard model. I have EM 1-3/4 headers and they're very nice, but the collector is a standard 4-to-1 collector like the TPIS one shone above.
GS977, those are definitely sweet headers! If it wouldn't cost me a marraige, I'd upgrade
GS977, those are definitely sweet headers! If it wouldn't cost me a marraige, I'd upgrade
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
FWIW, A couple of guys running big cubic inch small block's in C4's, actually still ran 1 5/8" headers and didn't lose any power verses running a 1 3/4" header....just food for thought... (and both cars ran deep in the 10's)