Silverboost

I figured I might be able to find some info on this by searching for it but came up with very little results. I have found plenty of threads saying what brand headers members have used at 600 + rwhp but it does not always say what size they are. I am at 709 rwhp with stock manifolds running a A&A kit and it is mainly a street car with a once or twice a year drag strip run. I am wondering if there is any reason not to go with 2" headers or are they over kill.

robert miller

If you get a good buy on the set that the guy in here has get them. But on no more power than that it would be a little over kill. I had 2 inch on the c5 set up RHS 427 ci with a F1X.

But it is a good price for the set he has for sell in here. He has mid pipe and all. Robert

Cordes Performance Racing

We tested making our headers in a 1 3/4, 1 7/8, and 2'' on bone stock vehicles and the 2'' made more tq and hp everywhere so that is all we produce.

Silverboost

Thanks for the replies. Looks like we have one for yes 2" is good and one for no. I will say I have never seen a dyno that shows a loss with 2". Anyone else have real world experience?

Higgs Boson

that's because dynos only measure full throttle power. are you planning to drive full throttle 100% of the time or do you think it will be full throttle about 1-2% of the time and somewhere between 0-65% throttle the other times.... I guarantee you will know the effects of a 2" primary on a mild build driving around normally.

imxz28

Sorry to go slightly off topic but I have been looking for info on A&A "actual examples". Please tell me which head unit you are running, which pulley and if you have other mods like heads/cam/intake.

My 2 cents on your original question.... I did lots of research and asked many tuners. An overwhelming response was 2" is best suited for 900+hp only. Hot Rod mag did an extremely comprehensive shoot out with various length and diameter headers on a 650hp range chev.
the general results found moderate gains at various RPM with the wide range of LT. I chose 1 7/8 and my target whp is 700ish. See Higgs post above, there's lots of truth in that which ties into RPM and throttle % as I hint above in the testing shootout. Get 1 7/8 like 99% of the rest of us... Unless you're going for 1000hp range. Let us know if you find anything different

Silverboost

I am definitely not here to argue the point that 1 7/8 are a great choice and seem to be chosen by most due to conventional wisdom that bigger is not always better and that the 2" might not have as good scavenger effect. What is interesting to me is that some believe and have proven ( such as a vendor commenting on this post) that a 2" header seems to have gains across the entire curve on a fairly stock set up.There was also a post yesterday on a diy header install with a fairly stock car that had great gains with a 2" header. With my car even if I am not running it full throttle the majority of the time it is producing substantially more power at part throttle than a non boosted application which is why I was looking for real world results.

FYREANT

I am interested to know this as well..

c6switchblade

I wish we could get some overlays for the 2" vs 1 7/8"... only because i do not think on a blown C7 application you lose any in the low rpms at all by going up to a 2" and only see gains at all rpms. Here is my graph with 2" ARH headers, I have more torque/hp than most, at lower rpms than most. Yes my setup is slightly more aggressive, but it only should be in the upper rpms. I feel like 2" is the way to go on a blown C7, the heads flow incredible from the factory and there the variable cam timing keeps power/tq up down low. Take a look at my graph and see for yourself. Stock cam stock heads stock displacement stock non npp.

imxz28

So this begs the question: Are you running a cam or different pulley? Maybe at Novi 2200 instead of 1500? Maybe the 2" agree with your set up? But let us know what that is. Thx in advance

c6switchblade

Yes I am on a 2200sl, it is not a 2200r and very similar to a 1500 in terms of flow in the midrange. The point is that this engine likes as much flow as you can get on the exhaust side due to the efficient heads and cam it has from the factory. Especially at the 700hp level. There are people using 2" headers with no blower at all and still making great gains with minimal to no torque loss down low.

C7-Beast

I'm running the ECS 1500 with Methanol injection and ARH 1 7/8 headers and put down 693 on 9.8 psi on a very hot day.

Jason 98 TA

I fully expect at 700rwhp you'll see 5hp gains from going to 2".

The good news is we are finalizing the TSP 2" headers and should offer them in the next 4-6 weeks! How can you beat a 2" header & x pipe system for about a grand???

thrilled

What I have been hearing is go with 1+7/8 for headers,SC,meth kit etc.That if you go for heads and A cam then go with 2".I'm just A messenger.

Higgs Boson

heads and cam is for sure 1 7/8, IMO.

big stroker 416 with supercharger, etc 2" makes more sense.

0Cajun @ Edgyvette

Just cant beat TSP quality at OBX price:th umbs: