Large improvement over 1 3/4" vs 1 7/8" headers?

[pbguy357]

I'm planning on redoing my entire exhaust system but do not want to drop Hp because of back pressure, a lot of people get the 7/8" because they plan on doing a lot to their engine, however, I plan on just redoing the exhaust and a few other bolt on's and not really planning on going over 500 hp, this being said, will i see a big difference between 3/4" over 7/8" headers?

[Knight]

Nope.

[pbguy357]

Ok. Will Lt's come with the extra length harness for the o2 sensors?

[TA98]

Some offer the option of plug and play o2 extensions, these are good. when i bought my pacesetters they came with wire to cut and manually extend my o2 sensor wiring, this = bad connection and will eventually lead to problems

[Knight]

Ok. Will Lt's come with the extra length harness for the o2 sensors?

None that I know of do. I would suggest getting Bosch 13111s instead, though. Some have had issues with the extensions. The Boschs come with long enough wiring to reach the factory plugs.

[TA98]

^^^^ also this is good. i knew there was a part number for those but can never remember the number

[pbguy357]

I was looking at kooks, would this be a good brand for 1 3/4"?

[Mr. Luos]

Yes.


I have seen cars have issues with the Bosch O2's though. Throw the code for them even with brand new O2's. I imagine it depends on the header manufacturer and distance to the O2.

[Z28_Driver]

BBK headers come with extra wire to splice into the harness for the O2 sensors. Its only a couple dollars worth of wire so dont let that make your descision for you.

[35th-ANV-SS]

Just get 1-7/8. It will not hurt you at all and Kook's are one of the best, if not the best. I have a set of 1-7/8 Kooks and the fitment was great. They tuck up real nice. It may take a little finessing though. Plus, stainless steel looks pretty

[bpopham22]

^^^^^ 35th is right, I have 1 7/8 stainless American racing headers. They fit great and are on the same level as kooks,can't go wrong with either one,might wanna get your motor mounts swayed put to polyurethane cuz f bodies have a problem with the y pipe banging on the body. I had mine swapped and the mang wad gone. Plus headers just look badass under the car too!

[pajeff02]

I run the Kooks 1-7/8" LTs and the 13111 senders on our car. Great setup, but if I was not planning on increasing the engine's "huff factor" in the future, I would have purchased the 1-3/4" LTs. They say that the trade off running the larger headers on a stock setup is a slight loss of low end torque. Whether or not this is true, I have no idea.

[Mike0202]

If your not doing interals its not going to matter. I doubt there would be any difference in track times between the two. I know there was a guy on ls1 tech comparing dyno sheets from different days but thats really not worth anything.

[Firebirdjones]

1 3/4" vs 1 7/8" is somewhat old news. They had interesting comparisons on a stock LS1 many years ago, on the same dyno, same day.

The 1 7/8" headers outperformed through the entire rpm range and didn't kill any bottom end. The difference on this stock engine wasn't much however, single digit HP and TQ. The 1 7/8" would really start to shine even more on a modifed engine, heads, cam, compression etc...

I also use the Bosch sensors #13111 on both cars and have absolutely no problems what so ever. Works excellent.

[az gt eater]

^^^^^ 35th is right, I have 1 7/8 stainless American racing headers. They fit great and are on the same level as kooks,can't go wrong with either one,might wanna get your motor mounts swayed put to polyurethane cuz f bodies have a problem with the y pipe banging on the body. I had mine swapped and the mang wad gone. Plus headers just look badass under the car too!

Should have done pacesetters, i did mine myself. (I'm a roofer) and had no problems with banging. Real nice and tight.

[TransAmX2]

if your o2 sensonrs are fine (and if you now have 2 extra of them assuming you are deleting out the rears) you can just get the o2 plug in extenders. I got mine from TSP for $40 for the pair and they work great. A lot cheeper than new o2's and I have 2 spares I can plug right in if I ever have a question or problem with one on the car.

[35th-ANV-SS]

Should have done pacesetters, i did mine myself. (I'm a roofer) and had no problems with banging. Real nice and tight.

Pacesetters are not stainless steel so I really don't consider them comparable to either Kooks or ARH's.

I had no issues with fitment with mine and my 3" ORY. I have a little over 4" of clearance at the collector from the ground and I am lowered on Strano springs.

[jiveass]

if you arent goin to to much mods, then might as well go the cheap route with the stainless 1 3/4" ebay headers...they cost me $160....with the flowmaster merge and custom made y-pipe, o2 extensions, and egr block off plates, total project cost around $450.....

[35th-ANV-SS]

A lot of people on here have had good success with the e-bay headers. There are a couple extensive threads about them if you use the search function and type in "e-bay & headers".

There are several different brands though so you may want to find out which seller people were going with if you decide to go that route.

[ntimid8r]

There's a sticky made from the research Hi-Po made. Great info!!
Link

Here's a cliff note referencing the OP's question;

"The 1 3/4 vs 1 7/8 battle - This will probably never stop being discussed. Personally, I would always go 1 7/8's on 346CI (LS1 5.7) The day I see back to back Dyno/Track runs where it proves that 1 3/4 gained power, I will edit this. Until then, buy 1 7/8's, they will make more power."

Here's how I take this "debate". Stock or mild motors will flow great with 1 3/4" headers. If you've done major motor mods (i.e. heads, big cam, etc) basically a race setup, then you'll need to step up to 1 7/8" headers. It's all about flow and getting the right exhaust pull from your motor. Too big won't suck the exhaust out as efficiently. Oh and if you're FI...you'll want more flow so bigger is better.